مجله علوم و صنایع غذایی ایران
سال بیستم شماره 1 (پیاپی 134، فروردین 1402)

The aim of this research was to investigate the effect of basil, sage and chitosan edible coatings on the physicochemical properties of microwave-dried apple slices. In this study, apple fruit slices were coated with basil, sage and chitosan in three concentrations (0, 0.5 and 1%) and dried at different microwave powers (90, 180 and 360 W). The drying kinetics, color, texture and antioxidant activity of apple slices were investigated. The analysis of the data indicated that the drying of the apple slices happened only in the range of the descending speed period. These data were fitted with 7 different experimental models, among the models, the most suitable models for basil, sage and chitosan coatings were Midili, Approximation of diffusion and Verma, respectively. Midili was able to predict moisture content more accurately than other models. Also, the amount of brightness, adhesivenes, cohesiveness and antioxidant activity increased with the increase of coating concentration and microwave power, but the amount of redness, yellowness, browning, general color change and hardness decreased. In general, edible coating is one of the new methods that increases the shelf life and quality of the final product. Therefore, it is recommended to treat fruits using edible coatings to increase the appearance quality and improve the color at the end of the drying process.

The present study aims to extract cellulose fibers from the walnut shell using dielectric barrier discharge (DBD) plasma pretreatment and to evaluate its properties. For this purpose, powdered walnut shells were exposed to 18 and 20 kV DBD plasma for 10 min in three stages. First, before sodium hydroxide alkaline treatment, next, before sodium chlorite bleaching treatment, and then, before both alkaline and bleaching treatments. The extraction efficiency, FTIR, XRD, thermal properties, FESEM and diameters of the cellulose fiber were evaluated. Based on the results, the extraction efficiency was significantly affected by applied voltage (p<0.05) and due to plasma destruction of glycosidic, the efficiency was reduced. The removal of peaks related to impurities from the walnut shell and the purity of all extracted cellulose was confirmed with FTIR. The results showed that applying DBD plasma during cellulose extraction did not affect its crystal structure, but the reduction of crystallization index was observed. Furthermore, the effect of plasma on the thermal-gravimetry of the samples was observed at temperatures below 100 ° C, and after the onset temperature of degradation, the behavior of the treated and untreated fibers until the final thermal decomposition was not significantly different. The microstructure of plasma-treated samples showed an increase in cellulose fiber's roughness and swelling, followed by the transformation of microfibrils to nanofibrils with a diameter of 80 nm at the higher voltage. In general, the results showed that applying 20 kV DBD plasma in both stages before the alkaline and delignification process is a more suitable treatment for extracting cellulose and producing cellulose nanofibers.

The aim of this research was to prepare a nanocomposite film based on Barhang (Plantago major L) seed gum. Zinc oxide (ZnO) and cellulose nanofiber (CNF) nanoparticles at the concentrations of 4 and 8% w/w were incorporated for improving the morphological, structural, thermal, water vapor permeability and mechanical properties of films. The FT-IR results confirmed the occurring of new interactions between nanoparticles and mucilage polysaccharides. XRD results indicated that the effect of ZnO on semi-crystalline structure of Barhang film is higher than the effect of CNF. The neat film has a smoth surface, but the roughness increased by addition of nanoparticles. According to TGA results, the thermal stability of films was affected by incorporation of nanoparticles, but the effect of CNF on improving the thermal stability of film was more than ZnO. The addition of nanoparticles at the concentration of 4% had no effect on the thickness of films but by increasing to 8%, the thickness increased. Moisture content and moisture absorption of films was also decreased significantly by incorporation of nanoparticles. The water vapor permeability of films was dependent on the concentration of nanoparticles and at 4%, it decreased significantly but at 8% concentration, the permeability increased again due to the aggregation of nanoparticles and their hydrophilic nature. The water contact angle of films’ surface increased by addition of ZnO but the CNF caused to decrease this value due to its hydrophilicity. The effect of CNF on improving the mechanical properties of films was better than ZnO. The CNF had the most effect on increasing tensile strength, elastic modulus and elongation to break. In general, this research indicated that by using organic and inorganic nanoreinforcements, the improving of the properties of Barhang seed gum based films is possible and the effect of CNF is more than ZnO.

In this research, physicochemical properties, texture and microstructure of traditional Kope cheese prepared in two different types of packaging (jar and plastic) and at two different ripening temperatures including soil (8-12 oC) and refrigerator (5-8 oC) During the ripening period (60 days) was examined by factorial experiment in a completely randomized design. The results showed that the amount of acidity, moisture, ratio of total nitrogen to dry matter and water-soluble nitrogen to total nitrogen in ripened cheeses in plastic packaging was significantly higher (P<0.05). Regardless of the type of packaging, samples ripened at soil temperature had higher acidity, total nitrogen to dry matter ratio, and water-soluble nitrogen to total nitrogen. Investigation of rheological properties and microstructure of Kope cheese showed that the packaged treatments in jar at both soil and refrigerator temperatures have less moisture and therefore a firmer texture. While plastic-packed treatments at both soil and refrigerator temperatures have more and smaller pores and as a result have a spongy structure and softer texture compared to the other two treatments.

Microencapsulation is a common method to improve the viability of probiotic bacteria against environmental stresses. In this research, by using double emulsion with Persian gum, emulsion stability, physicochemical properties, microcoating efficiency and microcoating viability were investigated during storage and in a simulated gastrointestinal conditions of the digestive system. Encapsulation of Lactobacillus acidophilus in double emulsion (W/O/W) with Persian gum improved the survival under storage conditions at 4 °C for 28 days, and only 0.58 log decreased and free bacteria after passage 7 days reached zero. The microcoating efficiency was 88% and the emulsion stability was between 85% and 95.43%. The optical microscope image showed a distinct double emulsion. In the simulating conditions of the stomach, the number of bacteria decreased by 1.97 log for the micro-coated treatment and by 3.9 log for the treatment containing free bacteria, and in the simulating conditions of the intestine, it decreased by 0.45 log for the micro-coated treatment and for the treatment containing free bacteria. 1.3 decreased. The particle size was (525 nm), zeta potential (-44.68 mv) and dispersion index (0.33). The results showed that the use of Persian gum double emulsion improves the survival of Lactobacillus acidophilus against storage conditions and the simulated environment of the digestive system.

In this study, the effect of turmeric extract and omega-3 encapsulated with soy lecithin on the characteristics of hamburger during the 12-day storage period was investigated. The results showed that during storage for 12 days, the highest pH and water holding capacity were related to the control sample. The initial moisture content of hamburgers was about 52%, which decreased significantly after the storage period (p<0.05). The lowest shrinkage was compared to the control sample, and the highest cooking loss was observed on the first day of storage. In all the investigated days, the highest volatile nitrogenous compounds was related to the control sample. Free fatty acids increased significantly during storage (P<0.05). The samples containing the extracts were not significantly different from the control samples in terms of texture characteristics. Encapsulated treatments had lower bacterial counts than free extracts. The control sample significantly received the lowest score in all sensory characteristics. In general, the quality of hamburgers containing fine-coated turmeric extract and omega-3 improved compared to the control sample.

In this study, water absorption characteristics of white rice during soaking at 25-65 oC was investigated. In the next step, the efficiency of fundamental and empirical models to predict the moisture content of grain during soaking were evaluated and compared. The fundamental models were developed by using analytical and numerical solutions of Fick’s second law of diffusion based on regular shapes (cube and cylinder) and the real geometry of the white rice, respectively. Five empirical models (Henderson and Pabis model, exponential model, Page model, modified Page model and two-term exponential model) for explaining the soaking behavior of rice were also studied. The results of the studied models indicate that the numerical model were substantially more accurate than analytical model in describing the water absorption curves. The higher accuracy of numerical model can be attributed to the fact that this model selected appropriate shape to represent rice grains in the mathematical model. The average value of the effective water diffusivity at 25-65 oC was estimated to be in the order of 8.83×10-11 m2/s, by minimizing the error between experimental and numerically predicted results. Among the empirical models, the two-term exponential model was better than others in predicting changes in sample moisture during soaking. Overall, although both modeling approaches were able to predict the changes in moisture content of the sample during soaking, the numerical model was found to be more appropriate because it provided a more comprehensive understanding of the underlying physics of the process and the model parameters were directly related to measurable physical quantities.

Nowadays, natural pigments are widely used in the food, cosmetics and sanitation industries. In recent years, numerous researches have been done on the methods of extraction and evaluation of the properties of natural pigments. The purpose of this study is comparison of enzymatic and ultrasonic extraction methods for the antioxidant properties of chlorophyll extracted from alfalfa (Medicago sativa L.). Antioxidant activity was performed by three methods including DPPH and ABTS free radicals scavenging and ferric reducing antioxidant power (FRAP). The results show that the concentration of chlorophyll a in alfalfa is higher than that of chlorophyll b and also the enzymatic method demonstrates higher yield in chlorophyll extraction. In addition, higher concentrations of alfalfa extract showed higher antioxidant activity in inhibiting DPPH free radicals and ferric reducing antioxidant power (p <0.05). Also, with increasing the extract concentration, total phenolic compounds and flavonoid compounds increase (p <0.05). Due to the better performance, the enzymatic extracted chlorophyll was used to evaluate the antioxidant properties, inhibition of free radicals DPPH and ATBS and ferric reducing antioxidant power and the result shows the higher chlorophyll concentration, the higher antioxidant properties. Due to the appropriate antioxidant effect of alfalfa chlorophyll extracted by enzymatic method, its application in food, pharmaceutical and health industries can be evaluated and industrial scale extraction systems can be designed using this technique.

In this research, the effect of ultrasound treatment at different powers and temperatures on the drying process of cornelian cherry by infrared dryer was investigated and modeled. The effect of the applied power by the ultrasonic device at three levels of 0, 75 and 150 W and the effect of the ultrasonic treatment temperature at three levels of 20, 40 and 60 °C on the mass transfer rate and the effective moisture diffusivity coefficient during the drying process of cornelian cherry were investigated. The results of this research showed that ultrasonic pretreatment before drying cornelian cherry by the infrared dryer, by creating microscopic channels on the product surface due to the cavitation phenomenon, makes it easier for moisture to exit from the product and thus reduces the drying time. By increasing the ultrasonic power from 0 to 150 W, the average drying time of cornelian cherry decreased from 73.2 minutes to 51.4 minutes. By increasing the treatment temperature from 20 to 60 °C, the average drying time of cornelian cherry decreased from 69.7 minutes to 55.7 minutes. The effect of power and time of ultrasound treatment on the effective moisture diffusivity coefficient changes of cornelian cherry was investigated and the results showed that with the increase in the power and temperature of the ultrasonic device, the values of this coefficient increase. By increasing the sonication power from 0 to 150 W, it was observed that the effective moisture diffusivity coefficient increased from 6.63×10-9 m2s-1 to 10.11×10-9 m2s-1. The average effective moisture diffusivity coefficient of cornelian cherry treated at temperatures of 20, 40 and 60 °C were 7.26×10-9 m2s-1, 8.10×10-9 m2s-1, and 9.45×10-9 m2s-1, respectively. In order to investigate the drying kinetics of cornelian cherry, mathematical models were fitted to the experimental data.

Wheat germ is a high-nutrient byproduct of wheat milling, however it has a short shelf life and extremely restricted ideal intake due to the intensive activities of lipase and lipoxygenase. In order to increase the storage life of probiotic wheat germ containing Bacillus badius, the freeze drying method was used in this study, and the effect of using xanthan gum: maltoxtrin in different ratios of 0.3:1, 0.1:1, and 0.03:1 as the capsule wall on antioxidant properties and physicochemical characteristics of probiotic wheat germ during 360 days of storage was investigated. Three control treatments were also produced without probiotic bacteria and had the same quantities of gums as the treatments. A pure wheat germ sample was also analyzed on the first day, 180 and 360, along with the encapsulated samples, for better comparisons and the influence of applied treatments. The experiments used a completely random design, and the treatments were analyzed using SPSS software and comparing the averages using Duncan's multi-range test at the 99% confidence level. The use of xanthan gum and maltodextrin as wall materials increased the antioxidant qualities in encapsulated wheat germ, according to the findings of this study. The introduction of Bacillus badius bacteria as a probiotic resulted in a substantial decrease in oxidation indices in wheat germ (P<0.01). In general, it can be stated that Bacillus badius bacteria, as a powerful probiotic, can extend the storage time of encapsulated wheat germ. Furthermore, xanthan gum is proposed as a good material for wheat germ encapsulation to enhance shelf life.

According to the increasing demand of advanced societies for the consumption of functional foods, especially in dairy products, the use of natural-based materials such as plant essences in the field of enriching food products with their antimicrobial and antioxidant compounds, as well as the use of wheat germ powder as a rich source of dietary fibers and vitamins and minerals and their effects on the viability of starter bacteria (due to their prominent role in improving human health) are seem to be necessary. Investigating the effects of using processed essential oils and wheat germ powder simultaneously in yogurt is considered in this research. Sensory, physicochemical characteristics and bacterial conting of set yogurt including Streptococcus thermophilus and Lactobacillus bulgaricus, were tested during the storage period to study the simultaneous effect of plant essential oils and sprouted wheat powder. The essential oils used included tarragon and thyme with different proportions and at three levels (400, 1200, 2000 microliters per liter of yogurt). Yogurt physicochemical tests such as acidity and water holding capacity, hedonic sensory test, rheology test (apparent viscosity) and microbial count tests were conducted to check the viability of starter bacteria in yogurt during the 14-day storage period. Based on the results obtained from the analysis of variance of the tested samples, the concentration of essential oil significantly (p<0.05) reduced the acidity and viability of starter bacteria of the product, but it had not a significant effect on the viscosity the sensory characteristics. In this regard, thyme and wheat germ powder showed a negative and unfavorable effect, especially in high concentrations.

Today, pasta is one of the most popular foods, and the addition of bran into its formulation provides the possibility of producing a healthy, high-fiber food product. As some micronutrients may become unavailable due to complex formation by phytic acid, which is present in bran, reducing the amount of this ingredient may eliminate this limiting factor and improve its applications in foods. The raw bran used in this study was first ground into two mesh sizes, 90 and 120 micrometers and then, processed by two stages of dry/humid thermal processes, accomplished in an autoclave and oven, at temperatures of 121°C and 150°C for 90 and 20 minutes, respectively. The bran sample mixed with the pasta flour in proportions of 2.5, 5, and 7.5(gr/100gr flour).  The rheological characteristics of the mixed- flour pastes were analyzed by Mixolab test to determine the best formulation for the Sedani-type bran-enriched pasta. Van Soest and the high-performance liquid chromatography methods were used to evaluate the insoluble portion of fiber in acidic detergent and phytic acid, respectively. According to the results, two paste formulations containing 5 and 7.5% of the bran exhibited the best rheological properties. In conclusion, the pasta sample formulated with 5% of the processed bran showed the lowest cooking loss and the highest sensory scores compared to control and may be recommended as the best treatment.

The aim of the present study was to optimization of enriched yogurt with chia seed oil and mucilage. This purpose was done with the aim of maximizing omega-3 level and minimizing changes in physical and chemical properties (pH, titrate acidity, syneresis, dry matter, peroxide values and color changes) compared to the control sample. First, in order to increase the oxidative stability, chia seed oil was encapsulated with sodium alginate and chia seed mucilage using emulsification/ internal gelation method. The physical characteristics results showed that the enrichment caused a decrease in the syneresis, an increase in the water holding capacity and viscosity. Then, yogurt was enriched and optimized with free and encapsulated chia seed oil (0 to 4%) and chia seed mucilage (0 to 0.25%). The sample without chia seed mucilage and oil used as a control sample. The results of scanning electron microscopy images showed that the successful alginate-sodium-mucilage microfiber coating of chia seeds has been made with a uniform structure. Yogurt contained 3.41% encapsulated chia seed oil and 0.213% chia seed mucilage was selected as an optimum treatment. The results showed that the number of starter bacteria of optimum sample were not significantly different from the control (p˃0.05). The texture of the yogurts was found to be viscoelastic. The flow behavior index in all samples was less than one, which indicates the non-Newtonian (pseudoplastic) behavior of the samples. Herschel Balky model had R2 and lowest RMSE in both samples, which indicates the suitability of this model to investigate the shear flow behavior in terms of shear velocity of samples.

Hamburger is products of meat that has a lot of consumer due to high nutritional value, in addition to good flavor and its easy to use, also due to lack of chemical additives in its production process. Hawthorn medicinal fruit, with the scientific name of Crataegus elbursensis has gained wide fame in herbal medicine. In this research hamburger is mixed with hawthorn extract (at different concentration of 0, 0/5, 1, 1/5). The antimicrobial effect of hawthorn extract (Crataegus elbursensis) on Salmonella enteric and  Staphylococcus aureus bacteria growth, TBA,PV, TVBN and phenolic compounds  is investigated for a period of 45 days periodically at 0,15,30 and 45days. The resulats of microbial assey showed that mixed Hamburger significantly decreased Salmonella enteric and  Staphylococcus aureus bacteria growth during 45 days storage. Samples that mixed with hawthorn extract showed lower TBA, PV and TVBN values compared to control during the storage time. According to the obtained results, Hawthorn extract was able to Antioxidant and antibacterial effect in hamburger.

The aim of study was estimated and compared intra-laboratory quantification deviation (SIR) or measurement uncertainty (MU) as a performance Charateristics  in verification of  the implementation  step of quantitative test methods in food microbiology laboratories. The aerobic mesophilic colony counts of   microorganisms (ACC) and Enterobacteriaceae colony count (ECC), as two important and common tests in the microbial evaluation of all type of food was selected and interlaboratoary standard deviation estimation of selected food items: minced meat, hamburger, soy powder, pasteurized liquid eggs, pasteurized and UHT milk, ice cream, Fruit  juice, flour, cake and spice (PEPER) were calculated based on ISO-19036 standard method (2019). In this comparison, technical, matrix, distribution, confirmation and combined  Uncertinity were calculated and reported. Calculation of the technical uncertainty of the ECC test in (pasteurized and ultra-heated milk, ice cream, fruit juice and pasteurized liquid eggs) by created the artificial contamination on three levels with the target organism (Shigella felxseneri) and in other food items it was natural contamination, in the ACC test was only natural contamination was calculated. The technical uncertainty results of the ECC test ranged from 0.487 to 0.07 and in the ACC test, from 0.390 to 0.105 log10 cfu/g. The highest values of technical and matrix uncertainty were observed in meat, cake, hamburger and cheese samples, which showed the heterogeneous foods (solid and semi-solid) and the lowest values were observed in liquid (homogeneous) samples. Evaluation of variability and followed the uncertainty is proposed as a way to standardize the expression of variability associated with data obtained in microbiological methods to highlight the causes and extent of several influencing factors.