فهرست مطالب arash koocheki

Sorghum is a valuable source of starch for human use, being a drought-tolerant cereal grain that contains a large amount of starch (approximately 70%). However, native sorghum starch has limited application in the food industry due to its poor functional properties. Modification of sorghum starch would overcome its shortcomings and tailor it to the targeted application. Among physical methods, non-thermal plasma is a novel method for starch modifications. Plasma is an ionized gas including electrons, atoms, ions, radicals, and quanta of electromagnetic radiation that affects the functional properties of starch. The effect of plasma on starch is influenced by apparatus type, treatment conditions (feed gas, time, and power), and the source of starch. Two main mechanisms of starch modification are known as  cross-linking and oxidation together with depolymerization. Although the effect of plasma on many types of starch has been investigated, no research has yet been found on sorghum starch modification by non-thermal plasma. So, this investigation determines the effects of non-thermal plasma on sorghum starch to overcome the deficiency of the native form and to explore wider applications for sorghum starch.
 

 Sorghum starch was extracted by alkaline steeping and purified using toluene-salt-water treatment. Dielectric Barrier Discharge (DBD) plasma was performed to modify sorghum starch. The applied DBD plasma setup consisted of two flat rectangular aluminum electrodes with the dimension of 6.5×45 cm and 7×18 cm and an electrode distance of 3 and 6 mm for air and argon plasma, respectively. Each of the electrodes was covered with a mica sheet as a dielectric barrier. DBD reactor was supplied with alternating current (AC). The frequency was adjusted to 375 Hz. Starch samples were treated for 1, 10, and 20 min at 23 kV at atmospheric pressure. The amylose content of sorghum starch was determined by iodine binding colorimetry. Evaluation of other chemical parameters including protein, lipid, ash, and moisture was carried out according to AAC methods. The clarity was determined using a spectrophotometer at 650 nm. The swelling and solubility of 1.5% sorghum starch suspension (at 55, 65, 75, and 85 °C) were measured using the centrifuge method. The centrifuge-filtration method was performed to evaluate freeze-thaw stability of sorghum starches up to 4 cycles.
 

 Chemical parameters showed that the extracted sorghum starch was purified. The amount of protein, lipid, ash, and amylose was 0.39, 0.15, 0.59, and 29.23%, respectively. Plasma caused significant altering in sorghum starch properties. Compared to the argon plasma, the air plasma was more effective at increasing the clarity, solubility, and freeze-thaw stability. Increasing the time of treatment also improved the above-mentioned functional properties. The clarity of native starch (14.02%) was increased to 56.10% for the sample treated with air plasma for 20 min, probably due to intense oxidation and depolymerization of starch molecules. While the lowest clarity (13.07%) belonged to the 1-min argon plasma treated sample, this value was improved with increasing time of treatment. Probably cross-linked bonds were predominantly formed during the first minute of argon plasma treatment, resulting in a reduction of paste clarity, while a competitive depolymerization and oxidation reaction could be a reason for the increase of paste clarity. Solubility was increased for all treatments (except for argon-1 min). The highest solubility in each of the temperatures was found for 20 min air plasma treated sample. Depolymerization of starch molecules under plasma treatment produces low molecular weight fragments which leach out easily and increase solubility. The swelling power of 20 min air plasma treated starch was lower than that of native starch, probably due to the structural disintegration. Other samples had higher swelling power. The lower freeze-thaw stability of 1 and 10 min argon plasma treated samples may be due to cross-linking which increase retrogradation. The 20 min air-plasma treated sample had higher stability than other samples in 3 and 4th cycles of freeze-thawing. The freeze-thawing stability of other samples was similar to that of the native starch.
 

 Non-thermal plasma treatment improved the functional properties of sorghum starch. The best results were detected for the sample treated with air plasma for 20 min. Cross-linking may be the main reaction in the first minute of argon-plasma treatment. However, this mechanism was suppressed in a longer treatment time. It may also be stated that the effect of oxidation along with depolymerization was predominant in air-plasma treatment.

Breakfast cereal products are considered as an important meal for athletes and children. By changing eating habits and increasing the consumption of these products, choosing healthy and nutritious raw materials such as whole grains to produce breakfast cereals with great impact on people's health. Rice grain as a technologically important source of starch causes the expansion of extruded products. Since in the production of breakfast cereal and baby food products, exclusively starch with low amylose is used, this indicates the suitability of this source for productionof such products. During the dehusking process, about 14% of the rice is broken to smaller grains, which is commercially classified as a low-value product. The broken rice can be converted to rice flour and used as a raw material in various types of food products. To maintain consumer demand for healthy diets, it is necessary to use high-fiber flours because these types of products will be able to modify the process of decomposition of starch. Although the integration of fiber in products has technological challenges, but by using rice grain as an important source of starch, the technological properties, expansion index, volumetric density and texture (texture hardness and brittleness) can be accepted. At present, modified starch derivatives are widely used in the food industry due to the increase in the quality of the final product. In the production of ready-to-use products for flaking, puffing, a process called extrusion is used. In this process, the product suddenly loses its moisture and leads to the creation of a dense structure containing pores. In this study, the effect of extrusion cooking process parameters on the desired characteristics of flax and rice meal breakfast cereal product with desirable physicochemical and sensory properties was investigated. 

Extrusion: In this study, a parallel twin-screw extruder (Jinan Saxin, China) was applied, die diameter of 3 mm, and extrusion temperature of 140 ℃. Central composite statistical design was used to study the effect of feed moisture (12, 15 and 18%), screw speed (140, 170 and 200 rpm) and Flaxseed oil cake addition (10, 20 and 30%) on technological and functional properties expanded extrudates. The chemical composition of flax meal and rice flour was measured by standard AACC (2000) methods. The expansion ratio was calculated by dividing the mean diameter (mm) by the diameter of the extruder die (4 mm) (Brennan et al, 2008). Textural measurement: The hardness of the extruded breakfast cereals was measured using Texture Analyzer (TA plus Ametek, UK). The cylinder steel probe (2 mm diameter) was set to move at a speed of 1 mm/s The samples were punctured by the probe to a distance of 10 mm. Bowl life hardness: Breakfast cereal samples were immersed in whole milk (3% fat) at 5 ° C for 3 minutes, Then rinsing was performed for 10 seconds and finally the samples were tested similar to the tissue hardness test procedure before immersion by a tissue analyzer (Oliveira et al, 2017). The color parameters L* (lightness), a*(redness), b*(yellowness) values of the samples were determined by the Hunterlab machine (Reston VA, US) (Rhee et al, 2004). Water absorption index in terms of grams of bonded water was calculated. The WSI of the dry solids regained through the evaporation of the supernatant obtained from the water absorption test was calculated (Alam et al, 2019). Sensory evaluation was performed using a 9-point hedonic test. Response surface methodology was applied for experimental data using a commercial statistical package, Design Expert (version 7.0) for the generation of response surface plot and statistical analysis of the experimental data. 

One of the most important parameters in the evaluation of breakfast cereal products is the amount of bowl-life hardness, which in this study, the highest amount was obtained at the level of 30% of flaxseed meal, 18% moisture and the lowest amount of screw rotation speed. After immersing breakfast cereal in milk, by increasing the percentage of flax meal due to the harder flow path, moisture absorption decreases and thus prevents the expansion of the product and increases the density of the mass and the hardness of the tissue. Due to the formation of a layer of lipids and micelles on the surface of the product prevents moisture transfer and absorption, so tissue hardness decreases and bowl-life hardness time increases. In fact, the amount of moisture absorption is a good model that shows the potential of bowl hardness-life of the samples. It is also compact and dense, which increases the retention time of breakfast cereal texture. Moisture can also reduce the shear force as a plasticizer and increase the amount of moisture absorption of the product. While increasing the speed of screw rotation, the effect of shear force on starch dextrinization increases and reduces moisture absorption. Another important feature of breakfast cereals is the lightness index, the highest value of which was obtained at the speed of screw rotation, humidity and low flax meal level. In the study of sensory properties of products produced at meal levels less than 20%, moisture content less than 15% and screw speed of 200 rpm showed the highest overall acceptance.

Extrusion cooking studies were carried out with a view to develop an instant ready to eat porridge from composite flour based on whole oat meal and broken rice. Full factorial design was carried out to investigate the influence of variables, feed moisture content (23, 27 %), cooking temperature (120, 145, 170 c°) and ratio of whole oat meal: broken rice 25:75, 50:50 and 75:25 % on physicochemical and functional properties contain, final humidity, water solubility index, color and porosity of extrudates. Results showed that increasing feed moisture content and whole oat meal simultaneously, showed an increase in humidity. Water solubility index (WSI) decreased with increase in feed moisture content, however with increase in level of whole oat meal, redness and WSI increased and porosity decreased. Increase in cooking temperature resulted in the decrease in lightness, humidity and increase in porosity of the extrudates. These findings suggest that fortified instant porridge have the potential to be adopted and can be used as a vehicle to deliver micronutrients to these populations and that extrusion with high yield, somewhat enhances the levels of soluble fiber fractions.

Bread has a major role in the diet of people in Iran. One of the important factors affecting the quality of bread is the quality of wheat flour protein called gluten. Gluten is the principal structure forming elements of most baked products, contributing to the elasticity, cohesiveness and viscosity characteristics of the dough. Thus, gluten substantially control the quality of wheat flour based products. Due to the importance of the role of gluten and the requirement for improving the flour quality, providing a simple, economical, and efficient method to improve the technical quality of wheat and bread is also an important and controversial challenge. Oxidizing agents are generally added to the wheat flour to accelerate the natural maturing and the flour becomes paler and yields dough with improved baking properties. However, increasing concern about their adverse effects has highlighted the need for the development of alternative oxidants. Atmospheric cold plasma (ACP) is an emerging advanced oxidation process which has recently drawn considerable interest from food scientists. Therefore, the objective of this study was to investigate the effect of non-thermal plasma treatments on the properties of wheat flour.

For this purpose, medium wheat flour was prepared from local silages and treated with ACP at 25V for 0, 2, 4, 6, 8 and 10 min. Chemical composition of flour samples (moisture content, protein and ash) were determined using standard methods (AACC, 2002). Color properties, damaged starch water soluble index, wet gluten, gluten index, zeleny and falling number values, water and oil absorption capacities, swelling power and solubility of wheat flour samples were also measured.

The results obtained from the measurement of properties for the treated and untreated flour showed that the water and oil absorptions, swelling power, and solubility, wet gluten, gluten index, Zeleny number and whiteness increased significantly with increasing time, while the pH, moisture content, b * and a * indices, were decreased by plasma treatment. In addition, the results showed that ACP conditions have a significant effect on functional properties that can be created floursand products with various characteristics. The results showed that plasma treatment affected the gluten index and wet gluten and techno functional properties of wheat flour. Overall, this study demonstrated that non-thermal plasma is a quick, efficient way to improve the technological properties of wheat flour, as an alternative to chemical oxidants

Increasing diet-linked diseases and following that the consumers ongoing desire for healthier foods makes reduced-fat products of outstanding importance in the food industry. This study aims to reduce the fat content of sauces as a traditional condiment through the incorporation of air bubbles in the oil phase. Response surface methodology (RSM) was used for identifying the effect of aeration process variables on foam properties. However, the main challenge of reduced-fat foods is to ensure their acceptability. Recently fat taste has been introduced as a sixth basic taste. Fatty acids have been considered as the stimulus for this taste. So, linoleic acid as the stimulus for fat perception was added to the formulation to develop a product that tastes almost like full-fat versions but contains less fat. The advantages of aerated foods over conventional products are clear. Nonetheless, the determination of quality and sensory parameters during storage, marketing, and consuming is necessary. For this purpose, produced aerated sauces, along with commercial full- and reduced-fat sauces, were compared by measuring the acidity, pH, oxidative stability, and sensory properties.  Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were generated by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentrations (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) was analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For the purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero, low, and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties.  According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3400 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference (p>0.05) between the pH of the control and the linoleic acid containing aerated, as well as low-fat sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making the products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the full-fat one (p<0.05). Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance.   In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to develop reduced-fat alternative foods, which could also be meet the consumers' and marketing requirements. Required amounts of mono- and diglyceride (MDG) and oil were mixed. Then nonaqueous foams were obtained by whipping the MDG-oil mixtures. In the optimization study, the effect of MDG concentration (2, 6, and 10 wt. %), whipping speed (1100, 3250, and 5400 rpm) and time (5, 15, and 25 min) on foam properties (overrun and drainage) were analyzed using RSM. The foam obtained from the optimum process condition was used to produce an aerated reduced-fat sauce. Sauce preparation was performed according to a usual recipe with the difference that the fat content was replaced by nonaqueous foam. Furthermore, 3.00 mM of linoleic acid as a fat taste stimulus was added to the formulation. First, an aqueous phase containing ingredients was prepared. Then nonaqueous foam was progressively incorporated in the aqueous phase. For purposes of comparison, aerated sauces (0 and 3.00 mM stimulus), along with commercial sauces (zero and full-fat), were analyzed by measuring the pH, acidity, oxidative stability, and sensory properties. According to the results of the optimization study, the desired foam (overrun ≥ 60 %) achieved by oil containing 10 wt. % MDG at 3200 rpm for 10 min. Overrun increased progressively with MDG concentration but decreased slightly above 10 wt. % due to the difficulty of dispersing air bubbles in such a viscous gel. Considering the effect of whipping speed, and time, it was observed that mixtures reached their maximum volumes within 25 min. With a further increase in the whipping rate, the time required to achieve the maximum amount of foam was decreased. However, at high whipping speed (5400 rpm), foam volume decreased rapidly with time, and almost a lot of foam collapsed. The lowest and highest pH was related to zero and full-fat commercial sauces, respectively. There was no difference between the pH of the control and the linoleic acid containing aerated sauces. Over time, as the pH decreases, the acidity of the aerated sauces increased and making them products with appropriate microbial stability. Due to the significant reduction of fat amount, oxidation of the aerated sauces was much slower than the commercial ones. Appearance, taste, and texture characteristics of aerated sauces provided a sensory profile similar to the full-fat sauce. The aerated sauce containing linoleic acid had higher sensory scores, indicating its general acceptance. In this study, nonaqueous foam as a new approach for fat replacement in emulsion-based foods such as sauces was practically applied. The optimum aeration process conditions were determined by the help of experimental design. Two types of aerated sauces were prepared based on the linoleic acid concentration, and their physicochemical and sensory characteristics were compared with commercial sauces. The acidity and pH of the sauces were in the standard range, and also their oxidative stability was acceptable during storage time. Generally, the aerated sauce containing linoleic acid had relatively similar sensory profiles to the full-fat sauce. Therefore, it seems that nonaqueous foam could be used successfully to create reduced-fat alternative foods, which could also be meet consumers' and marketing requirements.

Kichi is a local sweet bread that is cooked in the west of Iran, especially in Chaharmahal and Bakhtiari Province. This product is traditionally produced and has a low shelf life and hard texture. Therefore, the aim of this study was to investigate the effect of xanthan gum (0, 0.1, 0.3 and 0.5%) to improve the quality of Kichi sweet bread. Also mean size area, porosity, fractal dimension, and color parameters of Kichi bread were evaluated. The results showed that addition of xanthan led to improving WHC. The results of the texture analysis showed that softer samples were obtained in the low concentrations of xanthan gum (0.1% based on flour) and gumminess in this sample was significantly less than other samples (p < /em><0.050). Also, the porosity of the product in the low concentrations of xanthan (0.1%) was similar to the control, but in the high concentration of xanthan gum, the porosity of the product reduced. On the other hand, the results showed that the addition of xanthan gum did not affect the fractal dimension of the product texture. In the case of product color, the xanthan had a significant effect on the L* and b* values of the texture. Finally, it can be stated that using 0.1% of xanthan gum in the formulation of this local bread led to the production of a quality product regarding color and texture. The sensory evaluation results of the samples showed that the addition of xanthan improves the sensory properties of the samples. In general, samples containing 0.1% xanthan had better texture and sensory properties.

Wheat is one of the most important food products around the world. That's why there is a need to produce it all year round. The process of reaching the new wheat during the storage period will bring about changes that will improve its characteristics. The effect of time storage wheat for 90 days (0, 45 and 90) at the Temperature 30 ° C and relative humidity 45% on the chemical and rheological properties flour by farinograph test were analyzed. A completely randomized design was used to perform the tests. The comparison of the averages was done by Duncan’s multiple-range test at a probability level of 95%. The results of this study showed that wheat dormancy for 90 days increased wheat quality indices such as gluten index and Zeleny sedimentation volume, but pH decreased and acidity increased (p <0.05) . Percentage of gluten, moisture and ash did not change significantly during storage. storage time was effective on enzymatic activity, so that the activity of α-amylase decreased significantly (p <0.05) . Wheat also held significant improvement in the farinograph dough properties such as Water Absorption, Dough Stability, Degree of Softening and Farinograph Quality Number (FQN).
According To improve properties quality and rheological flour, freshly harvested grain storage for 90 days is suggested.

Rice and corn flours are appropriate alternatives for developing gluten free products and modification of some of their properties such as water absorption index of flour due to extrusion process could be effective for improvement of gluten-free products quality. In this research, addition effect of extruded flour in 110 °C with 18% feed moisture, in four levels ( 0, 10, 20 and 30%) and hydrocolloids of xanthan and hydroxypropylmethylcellulose in two levels ( 0.5 and 1%) of each were studied in gluten-free bread formulation. The results were proved significant effect of extruded flour and hydrocolloids addition on evaluated characteristics so that specific volume and porosity were promoted with increasing level of extruded flour till 10%, but higher levels were caused reduction of these properties. Also, increasing of extruded flour  level was decreased crust L* and hydroxypropylmethylcellulose had more effect on crumb hardness reduction of gluten free bread in compared to xanthan. Finally with regard to features such as specific volume, porosity, softness, color and scores of sensorial test, gluten free bread formulation including 10% extruded flour and 1% HPMC was determined as appropriate formulation which had specific volume of 3.01 cm3/g, porosity of 65% and overall acceptance score of 4.1 in sensorial test.

In this study alyssum homolocarpum seed gum (AHSG) nanocapsules containing D-limonene were fabricated by electrospraying process. For this purpose, D-limonene emulsions with constant AHSG (0.5% w/w) and two different flavor concentrations (10 or 20% based on gum weight) were prepared. The effects of physical properties of emulsions (rheological properties, droplet size, surface tension and electrical conductivity) on the morphology of capsules were studied. The results indicated that the droplet size and electrical conductivity of emulsions was mainly affected by concentration of D-limonene. Consequently, morphology and particle size of nanocapsules obtained from two emulsions, were somewhat different due to their difference in flavor content. FE-SEM images confirmed the success of electrospraying process for production of round and smooth AHSG nanocapsules with narrow size distribution. AHSG nanocapsules showed high encapsulation efficiency (more than 87%). Stability assay revealed a relatively good storage stability of encapsulated D-limonene and the maximum loss in 90 days was 11.67%. The release of D-limonene from AHSG nanocapsules was performed quickly, completely and fairly uniform due to the small and uniform size of particles. The kinetic modeling indicated that the data of D-limonene release in both artificial saliva and deionized water media were well fitted to the Korsmeyer-Peppas models.

Considerable amounts of essential fatty acids in fish oil makes it possible to use in the production of functional foods to meet nutritional needs and beneficial effects on health. One of the major problems is their high susceptibility to oxidative deterioration and consequent production of undesirable flavor. At present, some synthetic compounds are used as antioxidants in food and biological systems, but the use of synthetic antioxidants is of concern due to their potential health hazards. Therefore, the use of natural antioxidants in foods is the first choice. Enzymatic protein hydrolysis has been applied to food industry by-products to produce foods with enhanced functional properties. Antioxidant and antiradical activity of protein hydrolysates from meat, skin, bone, viscera and roes of various aquatic species has been reported. Silver carp (Hypophthalmichthys molitrix) skin (SCS), as low price by-product from minced products processing plants is available in I.R. Iran. Amino acids composition and sequencing determines the functional properties of peptides, which depends on the source of protein, the method and conditions of preparation and molecular weight distribution of resulting hydrolysate. The enzyme type and hydrolysis conditions, including enzyme/substrate ratio, temperature, time and pH, can affect the peptides length and functional properties of protein hydrolysates. The effects of hydrolysate from SCS hydrolyzed by alcalase on some quality features and oxidative stability of microencapsulated Kilka (Clupeonella spp.) oil at pH 6.8 and 3.4 were investigated.

SCS was pre-treated with NaOH and acetic acid, washed and freeze dried. Proteolysis with alcalase (1% w/w) at 50 ºC, without pH adjustment, was performed for 4 hours with gentle stirring. Enzyme inactivated by placing the sample in a boiling water bath for 15 minutes. After centrifugation at 13000 g for 20 minutes, supernatant was removed as silver carp skin hydrolysate (SCSH) and freez dried. Emulsions were prepared with 31.25% dry material. 25% of wall materials (equal proportions of maltodextrin and Hi-Cap®100), fish oil 25% and SCSH (for preparing 1, 2, 3, 4 and 5 mg/mL treatments) in two adjusted pH 3.4 and 6.8, was used. Fish oil was refined using multi-layered column chromatography (alumina-silica gel), and fatty acid composition was determined. The emulsion pre-homogenized by the IKA Ultra-turrax at 15,000 rpm for 2 minutes and finally by a HSTO homogenizer at 350 bar for 5 circle, to produce microemulsion. Effects of treatments on the characteristics and oxidative stability of microencapsulated Kilka oil for 28 days in the dark at 45 ºC were compared by determination of surface oil, microencapsulation efficiency, free oil, emulsion stability (%separation), droplet size, optical microscopic observation of morphology and peroxidation stability.

Results showed significant differences between proximate composition of silver carp skin, before and after pre-treatment and revealed that applied method and conditions reduced the amounts of oil and ash to an acceptable level. No aggregation and cluster formation was observed in optical microscopic images of prepared emulsions. The effects of pH on the droplet size and microencapsulation efficiency were insignificant (p> 0.05), but the amount of free oil and emulsion stability were significant at ≥2 mg/mL concentrations of hydrolysate (p<0.05). Peptides effectively retarded the preoxidation of Kilka oil in the model system. Hydrolysate antioxidant power was dose dependent. Peroxidation trends were nonlinear for control and 1-4 mg/mL treatments. These trends continued linearly, with mild slope for 5 mg/mL, and was similar for 2 pH during 28 days. Hydrolysate of SCS may be used as a natural antioxidant for the production of stable microencapsulated fish oil for the enrichment of various kinds of beverages with a wide range of pH.

In this research, the gelation and interaction between Lepidium perfoliatum seed gum (LPSG) and Lathyrus sativa protein isolate (LSPI) were determined using dynamic rheology. Sequence of experimental sweeps of time-temperature, frequency, and strain were applied for LSPI-LPSG mixtures in the ratio of 20:1, 10:1, 5:1, 2:1 & 1:2. Rheological behavior of protein isolate was found to be different from that of LPSG and gelling point was raised during the heating period. By increasing LSPI concentration, storage and loss moduli were increased and gel point was determined at about 80 °C, which was dependent of concentration and occurred during cooling period. Upon heating-cooling process, mixed gels showed a biphasic profile: the first phase, characterized by a sharp increase in the storage modulus where protein gelling occurred and the second phase showing an increase in the storage modulus, corresponded to the build-up of a LPSG network. The results of the strain sweep test for mixing gels at the end of the temperature sweep test supported the above hypothesis. In addition, FTIR of mixed gel showed a bicontinuous network in which LPSG dispersed in LSPI continuous phase.

Saffron is the most expensive agricultural product in the world and Iran is the largest saffron producer in the world. Saffron contamination in different stages of the production process, in addition to quality loss leads to reducing credit in the global market and exporting. Therefore, it is necessary to select an appropriate method for inactivation the microbial flora of saffron. Among the common methods that used to inactivation the microorganisms, cold plasma is due to the potential benefits such as non-toxic nature, low operational costs, and a significant reduction in water consumption during decontamination, and the possibility of its use for a variety of food products has attracted much attention. Plasma is a state of ionizing gas, including ions, electrons, ultraviolet rays, and reactive species such as radicals, atoms and molecules that can ignite, which can inactivate microorganisms. in this research, cold plasma was produced using two types of gas including nitrogen and air, and the effect of plasma radiation at 0, 3, 6, 9 and 12 minutes on the chemical and microbial (Escherichia coli, Enterococcus faecalis, Mold and Yeast) properties of saffron were investigated. The results of this study showed that germicidal effect of nitrogen plasma was lower than air plasma and the plasma exposure time had a significant effect on reduction of microbial load and by increasing the time of plasma exposure, the inactivation of microorganisms increased. The maximum microbial reduction was observed in 12 minutes. Maximum reduction in microbial load was observed at 12 minutes and 18 kilovolt voltage, which reduced the population of Escherichia coli, Enterococcus faecalis, mold and yeast by 2/69, 2/48, 1/95 log cycle respectively, However, with increasing radiation time, the amount of crocin, picocrocin and safranal decreased (p˂0.05). Reduction of crocin, safranal and picocrocin in 12 minutes was 6/01, 4/04, 5/44%, respectively.

Rice and corn flours are appropriate alternatives for developing gluten free products and modification of some of their properties by different processes could be effective for improvement of gluten-free products quality. This study was conducted to study the effect of extrusion process on physic-chemical properties of free-gluten blend flour of rice and corn (1:1 ratio). For this purpose, extrusion treatments with variables of die temperature (110, 145 and 180 °C) and feed moisture (12, 15 and 18 %) were applied and features of water absorption and solubility index, damaged starch, color parameters, bulk density and thermal properties by DSC were investigated. The results showed that applying the extrusion process lead to significant changes in all measured features so that the water absorption, solubility index and damaged starch were increased from 1.88 g/g, 4.5% and 8 UCD in control sample to 4.4-7.1 g/g, 11.4-28.5% and 20.2-28.8 UCD in treated samples respectively, whereas bulk density and lightness were reduced. Study of thermal properties showed that gelatinization temperatures including onset (To), peak (Tp) and conclusion (Tc) temperatures were raised significantly but gelatinization enthalpy (∆E) was decreased. Finally due to occurred changes in flour samples during extrusion process, it could be concluded that this process can be suitable pretreatment for production of flours with different functional properties that may be useful for preparation of various gluten-free products.

The food industry generate large amount of wastes annually around the world Food wastes are excellent source of nutritional compounds such as proteins, dietary fibers, antioxidants, and several types of micronutrients Therefore management of recycling food by-products is more valuable with maximum efficiency, in order to manufacture added value and low cost food products. Recently the processing of various types of by- products by extrusion cooking technology has been considered as a high- efficiency process. In this project, the rotatable central composite design was used to investigate the effects of formulation variables containing tomato pomace : rice bran ratio (25: 75-75: 25% w/w), feed moisture content (12-18%) and extrusion conditions including screw speed (120-160rpm) on functional and physicochemical properties of extruded fiber supplement from (tomato pomace- rice bran) including (oil absorption index, bulk density, color indexes (L،* a*,b*) , antioxidant activity and water activity (aW)). The results showed that properties of extrudates were affected by formulation and extrusion conditions. Enhancement of screw speed increased oil absorption index The addition of fiber supplement increased the color indexes(a*,b*) whereas lightness (L*) and bulk density decreased. Increasing screw speed and moisture content caused a decrease in the antioxidant activity. By increasing moisture content and tomato pomace increased water activity (aW) of extruded products. According to optimization results, to provide a modified fiber supplement for application in dietary foods optimum condition was found to be the tomato pomace : rice bran ratio of (25: 75% w/w), screw speed of (137/63 rpm) and moisture content of (13/26%) that required to obtain oil absorption index (2/60g/g) , bulk density (0/6g/cm3) , lightness (L*)(57/18) , antioxidant activity (35/14) and water activity (aW)(0/17).

The main objective of the current study was to optimize gluten free doughnuts formula for which the effect of xanthan, guar and Transglutaminase (TGase) enzyme were investigated. Xanthan, Guar and TGase were added from 0 to 2% of flour basis to the basic formula. Treatments were designed based on the mixture design of the Minitab software. The optimum conditions were selected based on the oil absorption, hardness, color, porosity and specific volume. The results showed that the high oil absorption occurred at the high level of TGase in absence of gums and the minimum oil absorption happened at the triple point. TGase caused cross linkage between rice flour protein, potato flour protein, and soy protein concentrate, which led to making protein network, xanthan gum,creating viscoelastic properties and guar gum,generating inter-surface properties, finally resulting in the increase of porosity and specific volume of doughnuts respectively. The interaction between the components showed that increasing the amount of guar gum improved the lightness of doughnuts. Texture parameters showed that samples with just gums without TGase showed the highest hardness. The synergistic effects of these gums increased viscosity. Hardness was decreased by protein network induced by TGase. The results of this study showed that the formula containing all three components could simulate the protein network in the gluten-free doughnut. The optimum point was 0.98% of xanthan, 0.44% of guar and 0.58% TGase which showed the best responds.

Snack foods have become an important part of the people’s diets. During last decade demands for utilization of fruit and vegetable waste in order to their dietary fibers in value added food products has been increased. Carrot pomace is rich in dietary fiber that contains important functional and nutritional properties. Barley contains a high amount of dietary fiber, especially soluble fiber, which has essential role in reducing blood cholesterol level. In this project based on Central Composite Design, the effect of independent variables containing extrusion temperature (120-170 °C), moisture content (14-20%) and carrot pomace level (10-25%) were evaluated on expansion ratio, bulk density, WAI, WSI, hardness, color snacks were evaluated by panelists in terms of acceptance or non-acceptance. Results expressed that expansion ratio, lightness, total acceptability and WAI decreased by increasing the amount of carrot pomace. Reduction of expansion ratio and WSI and improvement of lightness and WAI were shown as increased in moisture levels. The hardness and bulk density decreased with an increase in temperature. When temperature increased up to 145°C, expansion ratio, lightness, WAI and WSI increased and decreased thereafter. The optimum conditions for barley flour-carrot pomace snack were determined at the maximum expansion ratio, L*, WAI and overall acceptability with minimum bulk density and hardness in a snack. The optimum condition provides the highest value of expansion ratio 296.1 (%), L* 65.087, WAI 4.931 (g/g) and overall acceptability 4.502 with lowest bulk density 1.22 (g/cm3) and hardness 6.756 (N). Accordingly, the optimum conditions for the snack are 10% carrot pomace, 148°C die temperature and 15.49% moisture. The approximate composition of the snack extruded and unextruded obtained under the optimal conditions. Extrusion did not affect the protein and ash contents but it decreased the fat content of snack. During the extrusion, the SDF increased from 7.63 to 9.27 g/100g while the IDF decreased from 5.24 to 3.71 g/100g. Extrusion cooking did not affect the TBG content in barley flour-carrot pomace snack. Extrusion cooking resulted in the conversion of insoluble to soluble fiber and well balance of both types of the fiber

Nowadays, frozen dough technology is used to produce bakery, pastry & cakes products. On the other hand, extrusion plays a role as a high-performance process in the food industry, which, given its unique characteristics, can replace many common methods of food processing. This study was carried out aimed to investigate the effect of freezing methods (slow and rapid) and the storage time of frozen dough under freezing conditions on physicochemical and sensory properties of extruded and non-extruded sorghum flour for producing a gluten-free product suitable for Coeliac patients. In this study, extruded sorghum flour (an extruder with a temperature of 150-160°C, a moisture content of 14%, a speed of 150 rpm, feeding of 40 grams per minute and circular matrix with a diameter of 5 mm and, in the last step, using a grinding mill and 0.599 mm mesh, flouring is done), non-extruded sorghum flour (100%), Xanthan gum (1% w/w) were used in cookie dough formulation. Two types of slow and fast freezing were used to freeze the dough of cookie. Slow freezing according to the method provided by X.u et al. (2009) and Ke et al. (2013). In a fast freezing method, rapid cooling rooms were used at -40°C for 30 minutes. After freezing, the samples were placed in polyethylene bags and stored for 0, 2, 4, 6 and 8 weeks in a refrigerator at -18°C (X.u et al., 2009). For the thaw process, dough pieces were placed in a refrigerator at + 4°C for 16 hours (Maizani et al., 2012). Baking was performed in a microwave oven at 180°C for 14 minutes. The properties of the final product, such as the ratio of expandability (AACC 10-52), textural properties (cookie texture were carried out using a TA.XTplus Texture Analyzer (Walker et al, 2012)), total gelatinization and enthalpy temperature(Using the DSC device and temperature range 7-157°C and heating temperature 10°C/min), color, percentage of porosity, shell thickness (Image processing technique and ImageJ software) and sensory evaluation were investigated in a completely randomized factorial. Statistical analysis of the results was done using a factorial arrangement of completely randomized design and comparison of the meanings using Duncan's multiple range tests at 5% level. Data analysis was performed with three replications using SPSS 18 software. The gelatinization temperature decreased with increasing times of storage; however, the total enthalpy of the process was increased. The results showed that with increasing freezing rate, the gelatinization temperature increased significantly (P≤0.05), and the total enthalpy of the process decreased and the cookie from frozen dough containing extruded sorghum flour has the highest gelatinization temperature and the minimum total enthalpy value. With increasing times of storage, the dough chewiness decreased significantly (P≤0.05) and the adhesion and stiffness of the dough texture increased. The dough chewiness increased with the increase in the freezing rate, however, the adhesion and stiffness of the dough texture decreased and cookie dough containing extruded sorghum flour resulted in a significantly higher chewiness and lower adhesion and stiffness (P≤0.05) of the texture compared to the non-extruded sorghum cookie flour in both methods of freezing. The extensibility ratio has significantly decreased (P≤0.05) with increasing the times of storage. The extensibility ratio of cookie was significantly increased with the increase in freezing rate (P≤0.05) and non-extruded sorghum flour samples showed a lower extensibility ratio relative to the extruded sorghum flour cookies. The dough freezing method also had a significant effect on the final cookie quality (P≤0.05). The stiffness of the cookie texture from the frozen dough decreased by increasing the dough freezing rate and its tissue was softer and cookie samples containing extruded sorghum flour have a significantly lower tissue stiffness compared to other samples. The stiffness of the cookie tissue increased significantly (P≤0.05) with increasing times of storage. L* parameter (lightness) significantly decreased (P≤0.05) with increasing the times of storage and decreased the yellowness factor (b*) and increased the redness factor (a*) significantly (P≤0.05) for the cookie made from frozen dough. The freezing rate had a significant effect (P≤0.05) on the lightness of the cookies. The parameters L* and b* decreased by increasing the freezing rate and the colors of these cookies were darker. Cookies containing extruded sorghum flour had the lowest level of L* and b* and highest level of a*. The porosity% and thickness of crust of cookie decreased significantly (P≤0.05) with increasing times of storage. These parameters increased significantly with increasing freezing rate (P≤0.05) and tissue porosity and thickness of crust of cookies obtained from the frozen dough containing extruded sorghum flour was significantly higher (P≤0.05). The results of the kinetics of cookie mass transfer from frozen dough showed that the effective moisture diffusivity of cookie was reduced by increasing times of storage. Overall, the results showed that the process of extruding sorghum flour has improved the physicochemical properties of the cookie, and the fast freezing process improves the quality of the cookie made from frozen dough, and in this condition extruded flour sorghum can be used as a suitable alternative to wheat. Also, the use of frozen dough for cookie production can be a good way to supply this product.

In this study, the use of extrusion technology in the production of functional fiber supplement from by-products of tomato and rice processing industries (tomato pomace and rice bran) was investigated. A rotatable central composite design was used to investigate the processing and formulation variables including screw speed (120-160 rpm), moisture content (12-18%) and tomato pomace to rice bran ratio (25-75%). The functional and physicochemical properties of texturized products including water absorption index (WAI), swelling (SW), hardness, and soluble dietary fiber content were evaluated. The results showed that WAI of product increased with the increasing of screw speed and tomato pomace to rice bran ratio. Increasing tomato pomace to rice bran ratio and moisture content caused an increase in swelling. The hardness of fiber supplement also increased with increasing tomato pomace to rice bran ratio. Increasing screw speed increased the content of soluble dietary fiber. According to the results, the optimized processing conditions for the production of fiber supplement with desirable properties including WAI (4.64 g/g), SW (4.61 ml/g), hardness (89.08 N) and soluble dietary fiber (11.09%) were as following, moisture content of 14.06%, tomato pomace to rice bran ratio of 26.43% and screw speed of 120 rpm.

Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ingredients can be incorporated in such films. Among edible films, protein-based films such as whey protein concentrate (WPC)-based films are more attractive because they also supply valuable nutrients and introduce acceptable mechanical resistance. On the other hand, these films present moderate barriers to moisture due to the hydrophilic nature of whey proteins. Essential oils (Eos) can be incorporated in to edible films in order to compensate (overcome) this defect. Since no published research has been found on integrating mastic tree sap (Pistacia atlantica sub sp. kurdica) essential oil into whey protein edible films, this essential oil was applied for WPC-based film in this research. Some species belong to Penicillium have been known as contaminants of dairy and fruit products. Among Penicillium sp., P. expansum is more popular for causing post-harvest damage of apples. In this study, our objective was focused on mechanical and anti-fungal properties of WPC-based films incorporated with mastic gum essential oil.
WPC, mastic tree sap and P. expansum were obtained from Multi Milk Company, Kurdistan mastic Gum Company and Persian Type Collection Culture, respectively. Extraction of EO from mastic gum was accomplished using water distillation or hydro distillation with the help of Clevenger-type apparatus for 5 hours to obtain a pale yellow oil. Solution (10%w/w) of WPC in distilled water was prepared. Glycerol (as plasticizer) was added to WPC solution at a ratio of 1:1 WPC: Glycerol. Then concentrations of EO (1000, 2000, 3000 and 4000 ppm) was added to solution and mixed for 2 min. In the next step, some characteristics of film were measured including: thickness and density, water solubility, stability in acidic and alkaline solutions, water vapor permeability and light transmission / film transparency. Some mechanical properties of films such as tensile strength (TS) and elongation at break (%E) of films were also determined.
Regarding microbial assays, following the activation and preparation of fungi spore, MIC was determined using Agar Dilution Method. Determination of antimicrobial activity of film was performed according to film disk agar diffusion assay
With increasing essential oil concentration, film thickness exhibited increasing trend which was due to entrapment of micro-droplets of essential oil in film. Along with increasing EO concentration in film samples, WVP declined significantly (P-value

Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ingredients can be incorporated in such films. Among edible films, protein-based films such as whey protein concentrate (WPC)-based films are more attractive because they also supply valuable nutrients and introduce acceptable mechanical resistance. On the other hand, these films present moderate barriers to moisture due to the hydrophilic nature of whey proteins. Essential oils (Eos) can be incorporated in to edible films in order to compensate (overcome) this defect. Since no published research has been found on integrating mastic tree sap (Pistacia atlantica sub sp. kurdica) essential oil into whey protein edible films, this essential oil was applied for WPC-based film in this research. Some species belong to Penicillium have been known as contaminants of dairy and fruit products. Among Penicillium sp., P. expansum is more popular for causing post-harvest damage of apples. In this study, our objective was focused on mechanical and anti-fungal properties of WPC-based films incorporated with mastic gum essential oil.
WPC, mastic tree sap and P. expansum were obtained from Multi Milk Company, Kurdistan mastic Gum Company and Persian Type Collection Culture, respectively. Extraction of EO from mastic gum was accomplished using water distillation or hydro distillation with the help of Clevenger-type apparatus for 5 hours to obtain a pale yellow oil. Solution (10%w/w) of WPC in distilled water was prepared. Glycerol (as plasticizer) was added to WPC solution at a ratio of 1:1 WPC: Glycerol. Then concentrations of EO (1000, 2000, 3000 and 4000 ppm) was added to solution and mixed for 2 min. In the next step, some characteristics of film were measured including: thickness and density, water solubility, stability in acidic and alkaline solutions, water vapor permeability and light transmission / film transparency. Some mechanical properties of films such as tensile strength (TS) and elongation at break (%E) of films were also determined.
Regarding microbial assays, following the activation and preparation of fungi spore, MIC was determined using Agar Dilution Method. Determination of antimicrobial activity of film was performed according to film disk agar diffusion assay
With increasing essential oil concentration, film thickness exhibited increasing trend which was due to entrapment of micro-droplets of essential oil in film. Along with increasing EO concentration in film samples, WVP declined significantly (P-value

In the present study, optimization of fenugreek gum extraction for maximum values of yield, viscosity, total carbohydrate and minimum value of protein was done using response surface methodology. A central composite design with three independent variables including extraction temperature (25-75 ℃), extraction time (1-4 hr), and water to seed ratio (20-60 ml/g) was used to study the behaviour of variables. ANOVA results showed that second-order polynomial model was the best for interpretation of responses' behaviour. Statistical analysis revealed that all the variables significantly (p0.05). Applying numerical optimization method, optimum extraction conditions were found to be extraction temperature of 60.71 °C, extraction time of 3.33 hr, and water to seed ratio of 44.6 ml/g. At the optimum point, extraction yield, viscosity, total carbohydrate and protein content were evaluated to be 21.18 %, 29.06 m Pa.s, 70.98%, and 4.19%, respectively. Furthermore, the antioxidant activity of the extracted gum at optimum point was evaluated by determining DPPH radical scavenging activity, Ferric reducing antioxidant power (FRAP) and hydroxyl radical scavenging activity. All the above antioxidant evaluation indicated that fenugreek gum exhibited reasonable antioxidant activity in a concentration dependent manner. The fenugreek gum showed 43.23% DPPH radical scavenging activity, 650.76 μΜ FRAP and 46.95 hydroxyl radical scavenging activity at concentration of 1 mg/ml which were 50, 67 and 53.50% of ascorbic acid, respectively.

In this research, the chemical and microbiological characteristics of white brined cheeses produced with five different starter cultures, namely: traditional kefir grain, commercial kefir, commercial yogurt, traditional yogurt and commercial cheese starter culture, were examined during 60-day ripening period. Results of statistical analysis showed that the type of starter culture had a significant effect on pH, acidity, fat, protein, moisture, enterobacteria, total counts, mold and yeast as well as on lactococcus (p < 0.01), and lactobacillus level (p < 0.05). pH, acidity, fat, protein, total count, mold and yeast, and lactobacillus level (p < 0.01) were significantly affected by starter culture type during ripening period. However, moisture, enterobacteria and lactococcus level in all cheese samples were not affected by ripening period. Whereas other parameters including pH, fat and protein content showed decreasing trend during ripening. Among chemical analyses, cheese produced with traditional kefir had highest pH and cheese produced using commercial kefir showed highest acidity and moisture. Among microbial parameters cheese produced with commercial kefir starter had the lowest total microbial count and after that cheese using traditional kefir starter. It is concluded that traditional kefir grain can be used as a starter culture in production of functional white brined cheese.

Celiac disease is a digestive autoimmune disorder caused by the digestion of gluten. As of current, the only known treatment for this disease is to get a gluten-free diet. In this study, sorghum flour (extruded and non-extruded), xanthan and Lepidium perfoliatum seed gum were applied at three concentrations, namely 0, 0.3, 0.6 and 1.0%, to improve physical and chemical characteristics of gluten-free cookies. The cookies were subjected to physical and chemical characterization (spread factor, textural properties, gelatinization temperature, enthalpy, color, percent porosity, and crust thickness) and sensory evaluations. The results showed that, the cookies made from extruded sorghum flour (100%) containing Lepidium perfoliatum seed gum at 0.3% had the lowest L* and the highest a* and b* contents. Moreover, the samples composed of non-extruded sorghum flour had the highest adhesiveness and stiffness, while post-baking stiffness of the cookies composed of extruded sorghum flour was lower than those of other cookies; i.e. the cookies made from extruded sorghum flour were of softer texture. These cookies had also the highest spread factor, percent porosity, and crust thickness, and these properties were observed to increase with increasing the gum concentration. Overall acceptability of the cookies made from extruded sorghum flour was significantly higher than those composed of non-extruded sorghum flour, indicating extruded sorghum flour as an appropriate ingredient for producing gluten-free cookies.

Microencapsulation has become an important technique in the food industry. One of the methods of producing microcapsules is to use layer-by-layer adsorption, in which oppositely charged polyelectrolytes are adsorbed consecutively onto a colloidal template. Creating multilayer films based on electrostatic interactions between oppositely charged components was introduced in 1991 by Decher et al. Layer-by-layer (LbL) polyelectrolyte deposition has become a popular technique for preparing polyelectrolyte capsules because of its ability to create highly tailored capsule shells through a simple, inexpensive and easily controllable adsorption process. It has been applied to produce capsules of various sizes, ranging from the nanometer to micrometer scale, with well-defined barrier properties. In this technique, assembly is driven by the electrostatic attraction of oppositely charged materials to form polyelectrolyte shells. The structure of the polyion layered capsule shell is determined mainly by the electrostatic interactions between the polyions used. The mechanical strength and permeability of the capsules can be controlled by varying the number of layers or by changing the characteristics of the encapsulating materials. The purpose of this study was to produce microcapsules using supramolecular assemblies consisting of common food ingredients such as soy protein isolate (SPI) and high methoxyl (HM) pectin. Moreover, some features of the developed microcapsulation were studied.
SPI fibrils were prepared based on the method developed by Akkermans et al., (2008) and its morphology was studied using transmission electron microscopy (TEM) and atomic force microscopy (AFM). 0.5% (w/w) SPI fibril and pectin solutions were prepared by mixing at pH 3.5 were left stirring overnight. The LbL process for the production of microcapsules with protein fibril-reinforced nanocomposite shells has been described in Humblet-Hua et al., 2012. It starts with the production of A 2% w/w emulsion of (0.05 gr diacetyl in 1.95gr sun flower oil) in fibril SPI solution is produced using a homogenizer with a rotor-stator dispersion tool using a setting of 13500 rpm for 90 S. Because the proteins are below their isoelectic point, the emulsion droplets have a positive charge. To avoid interactions between the nonadsorbed SPI and the biopolymer of the next layer, the droplets are separated from the serum by means of centrifugation. After the isolation, the droplets are dispersed into a solution of HMP. The HMP is negatively charged at the chosen pH of 3.5. The bilayered droplets can be isolated again and dispersed in a fibril solution to deposit a third layer of a positively charged mixture of SPI fibrils. Subsequently, additional layers of HMP and SPI fibrils can be deposited by repeating the same procedures. Some features of the microcapsulation, including size, zeta potential, and morphology and release kinetics were studied.
TEM and AFM micrographs showed that SPI fibrils obtained had a contour length of a few hundred nanometers, thickness of between 1 and 10 nm and its structure is highly branched. One of the most common problems reported in previous studies using the LbL technique to produce multilayer particles, is the tendency for flocculation. In the present system, this problem was not observed. The size distribution of isolated emulsion droplets (templates) did not change significantly from 1-layer droplets to 5-layer droplets. In other words, the emulsion droplets were stable against flocculation after applying more layers of polyelectrolytes. The Sauter mean diameters D (3, 2) of these droplets fluctuated between 5 and 7 µm and slightly increased as the number of layers increased; noting that the emulsion droplets were poly-dispersed. Another possible problem that may occur using the LbL technique is the complex formation between non-adsorbed protein and the pectin molecules. These complexes with a typical diameter smaller than 1 mm were not detected here. Result showed that the zeta potential distribution of emulsion droplets reverses from about plus () 30 mV (odd number of layers with SPI fibrils as outer layers) to about negative (-) 20 mV (even number of layers with HMP as outer layers) confirming the layer-by-layer adsorption based on electrostatic attraction. Comparing SEM of microcapsules with various numbers of layers, an improvement in shell strength can be seen. Indentation is observed on 1-layer microcapsules showing that there are defects on the shell. They could be formed during the drying process or they are shell defects due to incomplete coverage of materials, meaning more layers are needed to fully cover the microcapsule shell. These defects are seen less on 5-layer microcapsules. These observations indicate that the more layers the more consistent the shells and the more resistant. It is against the physical drying process. Results showed that the time of the maximum in release shifts to higher values as the number of layers of the capsules increased. We clearly see that increasing the number of layers in the shell of the capsules leads to a delay of the release of diacetyl and maximum release time as a function of the number of layers is increasing steadily which show the release can be delayed even more by adding additional layers. These results prove that the release properties of the multilayer capsules can be tuned by controlling the number of layers in the shell of the capsules. The modeling results of four different kinetic models are indicated that the Rigter–Peppas was an appropriate model for diacetyl release prediction from multilayer microcapsulation. It could be attributed that the release mechanism is mostly governed by the Swelling–Fickian mechanism.
In this study, the microcapsules were produced using the LbL technique and food-grade SPI fibrils and HMP. The microcapsules had a poly-disperse size distribution. No flocculation of microcapsules during applying of additional layers was observed. It was found that increasing the number of layers, decreases the release rate of diacetyl. The diacetyl release data were kinetically evaluated by zero-order, first-order, Higuchi, and Rigter–Peppas models and the results showed that the release phenomena is mostly governed by the Fickian mechanism. Since the materials are food-grade, the applications of these microcapsules can include food products or pharmaceutical purposes.

Effects of Lepidium perfoliatum seed gum (LPSG) concentration (0, 0.3 and 0.6 wt%) and different processing treatments (freezing, pasteurization and sterilization) on physical and stability of oil-in- water emulsion prepared by whey protein (6 wt%) was investigated. For this purpose, particle size distribution, creaming index, microscopic characteristics, viscosity and flow behavior of emulsions were studied. Results showed that thermal processing increased the particle size of dispersed phase. Results also showed that the damage of membrane surface at high temperature such as sterilization was higher than other temperatures. At low Lepidium perfoliatum seed gum concentration, the emulsions were somewhat more resistant to thermal processes. However, at higher gum concentrations (0.3 and 0.6%), thermal processing did not have a negative effect on the emulsion stability. The viscosity and consistency coefficients also increased with increasing gum concentration. Shear thinning behavior for emulsions at all thermal treatments were also observed. Therefore, adding LPSG to the emulsion could increase its stability to the thermal processing.