فصلنامه پژوهش های صنایع غذایی
سال بیست و پنجم شماره 2 (تابستان 1394)

Honey is a highly nutritious foodstuff with medicinal properties. Due to the high price of natural honey and its high nutritional value, producing similar high sugar concentration syrups has become a common act of making adulterated honey. Increasing awareness of food safety and producing a healthy food and free from external substances for consumers, has shown the growing importance recently. In order to assess the quality of bulk and packaged nectar honeys, 11 samples gathered from different sources. Physicochemical properties of the samples including moisture content, diastase, pH, free acidity, hydroxyl methyl furfural (HMF), total ash content, total sugar content, fructose to glucose ratio, sucrose, insoluble solids and electrical conductivity were measured according to Institute of Standards and Industrial Research of IRAN (No. 92, Honey, properties and experimental methods. 6th Revision). Statistical analysis, t-test, showed that the applied thermal process in packaging of honey had no effect on the physicochemical properties of two groups of bulk and packaged natural poly-floral honey. Also there was no significant difference between diastase and HMF for two groups of honey.

The object of this study was to investigate the effect of microencapsulation by means of rennet, gelatin and locust bean gum (LGB) concentration, on the survival of probiotics and also physico-chemical properties of doogh like water phase volume, the apparent viscosity and acidity, during 29 days of storage. Due to this purpose, on the base of study experimental design, gelatin (0, 0.15 and 0.3%), LBG (0, 0.2 and 0.4%) and Bifidobacterium. animalis Subsp. Lactis in two forms of free and microencapsulated were used. 1unit /gr milk protein of transglutaminase was added in all treatments and results were compared to the samples without transglutaminase (blank doogh samples). Statistical analysis revealed, the colonies of the microencapsulated probiotics didn’t show significant decrease in comparison with the treatments containing free types, during the time of storage. LBG had a significant positive effect on the probiotics’ viability in addition of it's effect on the reduction of serum separation. Transglutaminase and gelatin also were effective on the prevention of serum separation; and simultaneous application of these compounds was more effective.

Hydrocolloids are defined as high weight macromolecules which could dissolve in water and give solutions with highviscosity or gels. In this study, the effect of sucrose, fructose, glucose and lactose at concentrations of 0, 1, 2, 3 and 4% w/w on the rheological properties of Balangu seed gum solution (1%) were investigated. Rheological properties of solutions were measured by a Brookfield rotational viscometer. Results showed that at all solutions, with increasing shear rate, the apparent viscosity decreased, indicating the pseudoplastic behavior of Balangu seed gum. Synergistic interactions between gum and sugars improved the viscosity of solutions and the amount of viscosity change depends on type of sugar. Apparent viscosity clearly increased from 23.1 to 35.1 mPa.s with increasing glucose concentration from 0 to 4 % (shear rate=61.2 s-1). Power law model well described non-Newtonian behavior of Balangu seed gum in the presence of sugars. Fitting with power law model showed that the consistency coefficient (k) and flow behavior index (n) were influenced by the type and sugars content. Addition of sucrose, fructose and lactose led to decreases in flow behavior index and increases in pseudoplastic properties of solutions. Interaction between Balangu seed gum and glucose was maximum and this solution showed the highest apparent viscosity.

Honey is a natural food with the high nutritional value and the most useful medicinal properties. The chief components of honey are simple carbohydrates and water, leading to the fraud in honey using cheaper commercially available sugar syrups. This is an important anxiety in quality control of honey. In this study, detection of pure natural honey from the honey adulterated by adding concentrations of 7, 15 and 30 percent of both beet invert sugar and date invert sugar was separately examined. For this purpose, multivariate analysis of physicochemical properties of honey samples were used. Applying principal component analysis (PCA), among 12 physicochemical properties measured, nine parameters were identified as principal components. Then the linear discriminant analysis (LDA) was utilized to discriminate the pure and adulterated honeys in three different batches according to these nine parameters. An optimum classification of 91.15% was reached using three physicochemical factors including pH, free acidity and ash. Correct classification of 85.84% were achieved by three others physicochemical properties, i.e. moisture content, electrical conductivity and reducing sugar, and of 82.30% by HMF, total sugar and Fructose/Glucose ratio. Results demonstrated that multivariate analysis in combination of the routine analysis of honey could be applied to rapid and easy detect of adulteration in honey.

The use of germinated cereals and grains on food industry is growing. Germination can have different effects on seed compounds. In this study, lentils and mung bean, two products that are used in the food industry were germinated and their effects on flavonoid content, total phenolic content and antioxidant properties were investigated. This experiment was arranged factorial experimental design in a completely randomized design with three replications. The germinated seeds were harvested after two, four, six and eight days. Total phenols, flavonoids, flavonol and antioxidant capacity were determinated by Folin-ciocalleu method aluminum chloride clorimetric method and DPPH method. The raw lentil seeds had the greatest rates flavonoids compare to raw mung bean seeds. But all the other days of testing, compared to mung bean, lentil sprouts had higher levels of flavonoids. The raw lentil seeds flavonol the greater than raw mung bean seeds. Germination modified the flavonol contents. On four days of germination, mung bean sprouts and eight days of germination, lentil sprouts had the highest levels of flavonols. And was also observed that after six days, germinated lentil seeds and after eight days, germinated mung bean seeds had the highest total phenols. The results indicated that eight days mung bean sprouts had the highest antioxidant capacity that in this period corresponded to the amount of total phenols. Antioxidant capacity on lentil sprouts were the greater than raw seeds and four days sprouts had the highest antioxidant capacity. In this condition, a great antioxidant capacity related to other antioxidant compounds in addition to phenolic compounds. The similar results were observed on mung bean.

A new gum was isolated from the roots of Acanthophyllum glandulosum. The incorporation of hydrocolloids is a suitable alternative to stabilize o/w emulsions against creaming. The effect of gum concentration and substitution on rheological properties and stability of o/w emulsions formulated using Chubak gum was studied in mayonnaise. In mayonnaise preparation, egg yolk was partially replaced by Chubak gum at the levels of 25, 50, 75 and 100% of total egg yolk. All samples exhibited shear-thinning flow behavior, which indicated a decrease in viscosity with increased shear rate and the detected from Herschel-Bulkley's model parameters: yield stress (τ0), consistency coefficient (K), and flow behavior index (n) were highly affected by gum addition. The addition of gum has increased the yield stress and consistency. Excellent emulsion stability was maintained. Hence, the results indicated that regarding to the desirable level of chubak gum, creation of low cholesterol mayonnaise with properties closely matching those of commercial ones was possible.

Now days disease which related to high fat diets increased and so trends to produce low or free fat products which have the high quality increased. Lots of compounds and additives are being used to improve and reduce fat (oil) in fried foods, of these Hydrocolloids are the main groups of these substances. In this research we try to investigate the effect of hydrocolloids Guar and xanthan on oil uptake and quality of eggplants. For this purpose, the amount of oil absorbed, product moisture content, dry matter, percentage of coverage and efficiency were determined frying. Results of coating the cover rings of eggplant with hydrocolloids, showed decreased absorption of oil in the final product. The maximum amount of fat loss related to sample coating with xanthan 1 and 0.5 % and the lowest amount of fat reduction were observed in guar 0.5 %. Xanthane gum at all concentrations showed a high rate of fat loss. The results showed that due to the nature of the barrier properties of the coating gums they have higher moisture levels in comparison with control samples.

In this method, image processing (fractal dimension) to predict the amount of wrinkles persimmon mixture osmosis-microwave drying process was used. Image processing software used for image j. Drying combination osmos- microwave persimmon was solutions of sucrose at a concentration of 40, 50 and 60%(w/w),10,20 and 30 minutes and at 30,45 and 60 ° C and the 300and 450 watt microwave. For prediction of wrinkles feedforward artificial neural network MLP with 4 inputs (the process) by neuro solution 6 was used. 9 neurons in the hidden layer network with the lowest mean square error, mean square error and mean absolute error for the predicted normalized fractal dimension of the intersection between the line and the background was dried persimmon (respectively 1/33, 0/49 and 0/002). Also, this model is able to predict the percentage of wrinkles with a correlation coefficient of 0/85 percent.

Bread is the main source of a large part of the energy, protein, minerals and vitamins required by humans. Aloe Vera is one of the oldest medicinal plants that beside of fiber, minerals, vitamins, amino acids and natural sugars, have antimicrobial agents, anti-inflammatory and antioxidant Therefore, its use helpful for the prevention and treatment of Alzheimers, heart disease, digestive problems. This study examined the effect of addition of aloe vera powder in quantities of 1, 3, 6 and 9% (w / w based on flour) on the quality of bagette bread, as well as changes in microbial, texture, color and water absorption properties of bread within 72 hours in order to produce the functional bread. The results showed that the adding of aloe vera powder, causing controlling the activity of microorganisms and mold and yeast, increase swelling power and reduce staling the bread. However, volume, brightness, Points smell, taste and the ability to chewing has declined. In general, investigation of breads characteristics in this study showed that the adding powder of aloe vera until 1%, causing improve the quality of shelf life and increase the healthly value of bagette breads that is produced.

Meat products are one of the most consumed food in the world. In response to consumer demand for natural products and their willingness to pay more for natural foods, meat industry try to find solutions to the consumption of foods with lower levels of fat, cholesterol and nitrite. For this purpose, in this research five concentrations (0, 1 %, 2%, 3%, 4% and 5%) of dry red grape marc powder as fat replacer were added to sausage and chemical analysis (moisture, ash, protein, fat, carbohydrate) and some of physicochemical were done. The results showed that fat content of low-fat treatments significantly decreased (P>0.05). Moisture, protein and carbohydrate content in treatments significantly increased but the pH of the control sample from 6/17 to range 5/54-5/87 in the other treatments reduced and ash was not affected (P>0.05).Sausages with dry red grape marc powder showed lower L*(lightness) and a*(redness) than control but b*(yellowness) was not affected. Cooking loss in all treatments was significantly higher than control. Also, reduction of fat and addition of dry red grape marc powder reduced lipid oxidation. Using dry red grape marc powder led to significant reduction in residual nitrite of the control sample from (55/37 mg/kg) to 23/5 mg/kg in sample 5.

Effect of dry and moist heat treatment of flour with low and high gluten contents on dough rheological properties such as water absorption, stability, degree of softening, development time and Farinograph Quality Number (FQN) was evaluated. The results showed that in high and low gluten flours, increasing the temperature and dry heating time led to an increase in dough water absorptions. With increasing thermal treatment temperature and time, dough development time increased as well. In both high and low gluten flours, the longest development time was belong to treated flours at a temperature of 120 °C for 120 min. The longest stability time was obtained for high gluten flours steamed for 15 min. Significant differences were not observed in other samples. In low gluten flours, with increasing thermal processing temperature and time, dough stability time was increased. In both low and high gluten flours, increasing dry thermal processing time led to a decrease in dough degree of softening values. Dry thermal treatment at a temperature of 120 °C for 120 min and steaming treatment for 15 min gave zero values for degree of softening. FQN was higher in high gluten flours compared to those of low gluten samples. The highest FQN was obtained for steaming for 5 and 15 min and dry heating at 120 °C for 120 min. In high gluten flours, increasing temperature and dry thermal processing time led to increase in FQN. In low gluten samples, there was not significant differences between samples in terms of FQN.

The purpose of this study was production of functional colored yoghurt using plant components for increasing the dairy product variety and improvement of their quality, nutritional properties and shelf life. In this study, 2, 4 and 6% of extract concentration were evaluated for producing the functional colored yoghurt based on sensory properties by panelists. The concentration of 4% (Brix 70) was selected for producing yoghurt samples using beetroot, spinach and tomato extracts. Then, colored yoghurts were evaluated on physicochemical, phenolic compounds, microbiological and texture properties every 7 days during 21 days storage. The results showed that spinach and control yoghurts had higher protein and fat content, respectively. pH, S. thermophiles and L. bulgaricus count decreased whereas acidity, syneresis mold and yeast count increased during storage period. In all yoghurt samples were not detected S. aureus and E. coli bacteria and coliform count was less than 10 CFU/gr which reflects the safety of the manufacturing process. Finally, results revealed that beetroot yoghurt not only had high sensory and nutritional quality (phenolic compounds) and acceptable texture (high viscosity) but also showed microbiological quality and high shelf life.

In this study, the influence of various parameters such as inlet air temperature and maltodextrin concentration on physicochemical and functional properties as well as production efficiency of spray dried malt extract powder was investigated. A pilot-scale spray dryer used for drying. Process variables were inlet air temperature and maltodextrin concentration (DE=18-20). Maltodextrin as drying aid in concentrations of 20, 30 and 40% (w/w wet weight of malt extract) was used. Inlet air temperature of 140, 160 and 180 ˚C in a co-current stream was used. In all experiments, atomizer rotational speed, feed flow rate, feed temperature and atomizer air pressure were kept constant at 1800 rpm, 10 ml/min, 30±1˚C and 4±0.1 bar, respectively. The least significant difference between means at p< 0.05 was calculated using on Minitab software. The results indicated by increasing inlet air temperature and maltodextrin concentration, powder production yield, particle size and porosity were increased, while moisture content, water activity, bulk density, tapped density, particle density, hygroscopicity, and color values were decreased. Moreover, powders solubility was positively affected by inlet air temperature and negatively influenced by maltodextrin concentration.

The effect of adding walnut powder in UF-white probiotic cheese at 3 level (2.5, 5, and 7.5%) was investigated. Cheese samples were ripened at 6ºC for 60 days and chemical composition such as pH, fat, dry matter, soluble nitrogen/total nitrogen, non-protein nitrogen/total nitrogen, sensory and textural properties of cheese samples were investigated. The results showed that pH of all samples were decreased. In contrast, fat and moisture of the samples were increased. During ripening, the percentage of SN/TN and NPN/TN significantly increased in samples with walnut powder (P<0.05) compared to control samples. Softer texture in control cheese were observed. Cheese with walnut powder had better odour compared to control samples. Samples with walnut powder had maximum flavor desirability until 45 days. After this time period, control samples acquired maximum score due to appearing bitter taste in cheese with walnut powder. Due to appearance feature, control samples acquired maximum score and samples with walnut powder acquired minimum score due to dark color that resulted from addition of walnut powder.

Recently, due to healthier and nutritional problems of synthetic antioxidants in food processing, using of herbal medicine and its effective components as a natural resources with antioxidant properties have beenevaluated. Different organs of Hawthorn have more important in food and medicinal science due to high antioxidant properties and various flavonoids and proanthocyanin content. This study was accomplished in order to examine the total phenolic content and antioxidant capacity of hawthorn different organs (fruit, leaves and flower) in 56 accessions. Antioxidant capacity and total phenolic content were determined using ferric-reducing antioxidant power (FRAP) and Folin–Ciocalteu assays. The amount of total phenolics was significantly (P<0.05) different in the both amongst species and different plant organs ranging from 7.21 to 87.73 mg GAE/g dry weight. Total phenolic content was in its highest value in the flowers of G7 (87.73 mg GAE/g DW), whereas the lowest level was found in the flowers of G4 (7.21 mg GAE/g DW). The Antioxidant capacity was widely different in the both species and different organs of the individuals ranging from 0.22 to 1.84 mmol Fe ++/g DW. Antioxidant capacity was in its highest values in the fruits of G1 (1.84 mmol Fe 2+/g DW), whereas the lowest capacity was found in the leaves of G18 (0.22 mmol Fe 2+/g DW). However, differentorgans and species of the genus Crataegus showed a high level of total phenolic content as well as antioxidant capacity.These results showed that different species of Crataegusespecially C. pseudomelanocarpa and C. pentagynaare promising sources of natural antioxidants and other bioactive compounds beneficial without any harmful effects to be used in the food or the pharmaceutical industries.