مجله تحقیقات مهندسی صنایع غذایی
سال نوزدهم شماره 1 (پیاپی 68، بهار و تابستان 1399)

Medlar (Mespilus germanica) is widely cultivated in northern Iran and used as an edible fruit as well as home remedies. Short storage life of medlar fruit and its high susceptibility to weight loss and browning are the main limiting factors for its marketability. The aim of current work is to study geometrical (extracted from image), physical (texture and color) and chemical (titratable acidity) properties of medlar to determine the maturity and ripening stages. These parameters are of high importance due to their relation with sensorial quality and their effects on ripening level of medlar. The results revealed that none of the factors mensioned above were stable during the experiment. Result indicated that the lightness (L*), titratable acidity, firmness, h* and ripening index (RPI) decreased during medlar cold storage; while redness (a*), yellowness (b*), and C* values, total soluble solids and pH of medlar increased during this period. The use of the RPI made it possible to characterize three ripening stages (Fresh Medlar (FM), Ripe Medlar (RM), and OverRipe Medlar (ORM)) during the storage period of medlar. The results also showed that there was a significant relationship between ripeness stage and geometrical properties of medlar.

The study of physicochemical and mechanical characteristics of sunflower seeds are important when the designing of control equipment’s, transportation, processing, and product storage are concerned. In this study, physicochemical and mechanical characteristics of four varieties of confectionary sunflower seeds were evaluated. Some of the assessed physicochemical and mechanical properties include: the content of total ash, fat, and minerals and also the mean length, width, thickness, diameter, sphericity, surface area, volume, 1000-grain weight, angle of repose, porosity, particle density and bulk density, hull and kernel percentage, coefficient of friction surface and axial compression test. The results showed that the highest amount of fat content (48%) and potassium content (76.639 mg per kg) were found in  sample number 3; and highest amount of  ash content (3.83%) and sodium content (25.318 mg per kg) were found in sample number 4. Physical properties of sunflower seeds were studied in five moisture content levels of 4% to 32% (based on dry basis weight). The results reaealed increasing trend in length, width, thickness, sphericity, geometric and arithmetic mean diameter, surface area, volume, 1000-grain weight, angle of repose, porosity and density upon increasing moisture content; while, bulk density decreased. The coefficient of static friction of all seeds at glass, chipboard, galvanized, and aluminum surfaces increased with the increase in moisture content. When the moisture content increased from 4 to 32 percent, the highest increase in the coefficient of static friction was observed in sample number 3 with aluminum surface and the lowest increase in the coefficient of static friction was observed in sample number 1 with glass surface. Based on results obtained from the axial compression test, the vertical loading force was found to be more than that the horizontal loading force and in all samples, the total vertical and horizontal loading forces were decreased by increasing the moisture content.

Protein nanofibers are obtained through heating the globular proteins above their denaturation temperatures at acidic pH. These structures have a length of about 1 μm and a diameter of about 1 to 10 nm and are very anisotropic. The main objective of this study was to produce nanofibrils from whey protein isolates, evaluate their appearance and functional properties in order to use them as ingredients in food. The protein nanofibrils were prepared at 90 °C at the concentration of 20 mg mL-1 then their appearance and functional properties were evaluated at pH 2, 4, and 6. The results obtained by atomic force microscopy showed that by increasing pH, the stability and the content of the produced nanofibrils decreased. Moreover, stable nanofibrils at higher pH values showed higher emulsion capacity and stability and higher solubility percentages. Also by increasing pH, samples opacity and turbidity and color parameters were increased. Nanofibrils also showed better functional properties compared to the control sample (P <0.05). In this way, protein nanofibrils can be commercially suggested as an additive to improve functional properties of food products. Desirable functional characteristics of WPI nanofibrils compared to the unprocessed native whey protein isolate, provides the possibility of their application to improve the qualitative properties of food products and as ingredients in foods for patients and elderly people and dietary and low-calorie foods.

Ice cream is a dairy dessert which has high nutritional value. The aim of this study was to enrich ice cream with phytosterol and to produce functional product. For enrichment of ice cream, different concentrations of phytosterol (1, 2, 3 and 4 percent) were added. The ice cream samples were kept at -18°C for two months. The physicochemical characteristics (acidity, total solids, over run, viscosity, and melting resistance) and sensory quality (flavor, odor, overall acceptance) of the samples were studied. The results showed that as the phytosterol content increased, acidity, fat, total solids, viscosity and melting resistance increased significantly (p < 0.05). Adding phytosterol decreased overall acceptance score of test samples, compared to control sample. During storage, acidity, viscosity, melting resistance increased significantly and overall acceptance decreased significantly (p < 0.05). The ice cream sample containing 4% phytosterol was selected as the best treatment regarding fat content, melting resistance, over run and viscosity. However, use of flavors can improve sensory quality of this functional sample.

Hydrocolloids, playing different roles including thickening, stabilizing, gelling and improving texture of foods, are among additives widely used for improvement of quality in food industry. Recently, demand for hydrocolloids with special functional properties has grown, so finding new sources of gums with proper attributes is of enormous importance. In this work, the effects of microwave and ultrasound power, time and temperature on the yield and quality of extracted mucilage from trehala manna were studied. The highest total amount of mucilage yield for microwave was found to be 54.99 % for 10.5 min of extraction at 90 W and 45◦C. It was observed that yield increased with an increase in microwave power and temperature. The highest yield (54%) for sonication was 150 W, time of 20 min in 60◦C.As a result, microwave extraction was selected as the optimal extraction method of trehala manna mucilage. The quality and quantity of sugary compound analyzed by high-performance anion exchange chromatography with pulsed amperometric detection.

This study was conducted to increase onion storage life in Hormozgan province. For curing onions, the Primavera and Texas Early Grano cultivar were placed in sunshine for two days. The bulbs were packed in a plastic net for three months in three traditional storages: optimized storage with a temperature of 33 ± 2°C and a relative humidity of 49 ± 4%, controlled storage with a temperature of 9 ± 1°C and a relative humidity of 65± 5%, and storage at a temperature of 5 ± 1°C and relative humidity of 70 ± 5%. Every 15 days, qualitative characteristics of the onions were measured, including: weight loss, germination percentage, total soluble solids, dry matter, and firmness. The results showed that during storage, significant changes were observed in qualitative traits of both onion cultivars. The percentage of soluble solids, firmness and dry matter of onions during storage were nonlinear. Total soluble solids of Primavera cultivar increased after 15 days and then decreased. After two months of storage, Texas Early Grano, comparing Primavera, showed higher storage life due to its higher solid soluble matter and higher dry matter content. At ambient temperature, after three months, the weight losses of both onion cultivars were one and a half times higher than that the initial maximum (11.51%), and in cold storages, after three months, the weight losses of both varieties were less than 2%. Both cultivars faced no decay after 45 days of storage in traditional aeration, with a weight loss of less than 3%.

In this article, the influence of temperature and roasting time on the oxidation and Color of pistachio oil was investigated. Roasting is one of the most important steps in pistachio processing, so optimization and modification of this process and also improvement of product quality are of high priority. In this study the process of pistachio roasting by hot air was investigated. The effects of different temperatures (120, 140, and 160°C) and times (20, 30, and 50 minutes) on the color and oxidation variation of roasted pistachio were evaluated. Qualitative tests relating to changes of color indexes include measurement of L, a, b, the general changes in color, the angle of the hue, the browning index and the peroxide index. The outcome of analysis of variance (ANOVA) showed that for all responses, there was a significant statistical difference between experiments. With increasing temperature and roasting time, all color indices changed; significant changes in the color of the final product is not desirable from the consumer's point of view. As temperature increased, the process of changing the color, including browning, became faster which indicated browning during roasting. Increasing time and temperature also increased the pistachio peroxide index which indicated fat oxidation in higher temperatures.

Obesity, diabetes, and cardiovascular disease are the most common diseases in industrial societies, and for this reason, the design and production of low-calorie, reduced or sugar-free foods has been highly regarded as a strategy. Masghati is a traditional Iranian confection with about 25% sugar content and therefore reduction of sugar causes some challenges in the texture and sensory properties of product. In this study, the sugar content of Masghati was replaced using different percentage of isomalt, stevioside and sucralose. Physico-chemical properties (pH, acidity, ash, moisture content, brix and total sugar), texture and sensory evaluation (taste, odor, color, texture, sweetness, overall acceptance) of different treatments were tested immediately after production and during storage time. The results showed no significant difference in pH, acidity and ash content of different treatments (p≤0.05). The addition of isomalt more than 50% w/w reduced the moisture content of the product while the firmness and brix increased the moisture content of the product. Addition of different amounts of stevioside and sucralose did not affect the overall acceptability of the evaluators but adding high amounts of isomalt reduced the overall acceptability and score. The use of sugar substitutes reduced the total sugar content in the Masghati and the lowest total sugar content (11.98%) was measured in the sample containing 50% (w/w) isomalt + 50% (by sweetness) stevioside + 25%(by sweetness) sucrose. In general, the results of this study showed that the combination of isomalt and stevioside is a good alternative to sugar in the production of dietary Masghati with reduced sugar.

Oil and eggs are essential ingredients in the cupcake formulation. But complete removal of oil and eggs is not possible due to their numerous functional properties. The aim of this study was to investigate the possibility of producing cupcake by removing half of the oil and half of the eggs in formulation and replacing wheat flour with pea flour (at 0, 15 and 30%) and addition of whey protein concentrate (WPC) and soy protein isolate (SPI) in amount of 10%. Based on the results, it was found that by increasing the amount of pea flour replacement and adding WPC and SPI in cake formulation, the moisture content of the final product was increased. The findings of this study showed that replacing the amount of pea flour to 15% had no significant effects on specific volume and porosity, while replacing up to 30% reduced the amount of these parameters. Also the results showed that the specific volume and porosity were increased by addition the protein sources to cake formulations. Also the samples containing 15% pea flour and WPC had the lowest firmness. On the other hand, the results indicated that by addition of pea flour and protein sources, L* and a* values of crust color decreased and increased respectively. Finally, the panelists introduced the sample containing 15% of pea flour and 10% WPC as the best sample in the sensory evaluation. Also, by comparing the best sample with the control, it was found that the best sample had the less firmness and oil (45% decreased), and higher protein content (18% increased) and overall acceptance than the control sample.

The main objective of this research was to compare of accuracy of three widely used simulation methods including mathematical thin0layer models, artificial neural networks (ANN), and adaptive neuro-fuzzy inference system (ANFIS) in estimation of instantaneous moisture ratio of microwave power dried potato slices. To predict the moisture ratio, seven mathematical models were used. Furthermore, based on the experimental data, microwave power, samples thickness and process time, and the moisture ratio were considered as inputs and output of artificial neural networks and adaptive neuro-fuzzy inference system, respectively. Designing of neural networks was performed based on multi-layer feed-forward back-propagation (MFFBP) and cascade forward back-propagation (CFBP) structures, linear (Lin), sigmoid hyperbolic tangent (Tan) and logarithmic (Log) threshold functions, and Levenberg-Marquardt (LM) and Bayesian Regularization (BR) training algorithms. For simulation by adaptive neuro-fuzzy inference system, Takagi-Sugeno fuzzy system was selected, structure of the fuzzy inference system (FIS) created by grid partitioning method, and the membership functions in fuzzy logic toolbar of MATLAB software used. Among the studied modeling methods, Midilli model, CFBP network with 3-10-10-1 topology, LM training algorithm and Tan-Tan-Lin function, and ANFIS model with sigmoid membership function in input and 3×3×4 fuzzy rules were found as the best models. Based on the obtained results, all the three modeling methods were capable t estimate the instantaneous moisture ratio with desirable accuracy. However, showing the coefficient of determination of 0.9997 and mean square error of 4.53×10-5, ANFIS model had the better performance in estimation of the experimental data.

Angutifolia contains a lot of protein, minerals, phenolic compounds and dietary fiber, and flour can be used as a primitive raw material for the production of bakery products. In this study, the effects of replacing wheat flour with angustifolia powder on bread viscosity, physicochemical and sensory properties of bread was investigated. For this purpose, the angustifolia powder was added to wheat flour at five levels of 0, 4, 8, 12 and 16 percent and the bread was prepared. As a result of increasing the amount of angustifolia powder, the fiber percentage, bread moisture and a * color component significantly increased and the percentage of bread protein and color components L * and b * had a significant decrease compared to the control. Specific volumes and porosity of breads containing angustifolia powder at a level of 8% had no significant difference with the control, but at higher levels the specific volume and porosity of the breads decreased. The tissue of breads, when 8% of the angustifolia powder was added, was softer than that the control but was tightened at the higher levels. In terms of general acceptance, the breads containing 8% of angustifolia powder had the highest score. According to the results, the samples containing 8% of angustifolia powder, due to its texture and sensory properties, were better than the control, they contain more fibers and less energy.

The encapsulation of essential oils in nanoliposomes is an effective method for protecting them from light, oxygen and chemical degradation. In this study, nanoliposomes containing kakuti essential oil were prepared from different concentrations of lecithin-cholesterol (60:0, 50:10, 40:20 and 30:30 mg) by thin-layer hydration-sonication method. The GC-Mass spectroscopy method was used to study essential oil composition and the results showed that Pulegone (49.05%) was the main component of essential oil. Particle size, poly dispersity index (PdI), zeta potential, and the encapsulation efficiency were evaluated to determine the physical properties. Antibacterial activity of nanoliposomes against E. coli O157H:7 were investigated using a disk diffusion agar method, the minimum inhibitory concentration (MIC) and minimum bactricidal concentration (MBC). The size of particles and PdI were in the range of 88.60-121.97 nm and 0.114-0.169, respectively. The results showed that using the highest concentration of cholesterol for preparing of nanoliposomes containing essential oil increased the size and PdI, but reduced the encapsulation efficiency. Cholesterol concentration did not have a significant effect on zeta potential, and only the sample containing 30 mg of cholesterol had a higher zeta potential. MIC and MBC of cholesterol-free nanoliposomes containing essential oils were 14 and 14 μg/ml and for the control sample (free essential oil) were 15 and 30 μg/ml, respectively. The antimicrobial activity of nanoliposomes decreased with increasing cholesterol levels in the samples. The results of this study showed that nanoliposomes could be a suitable carrier for kakuti essential oil to control the growth of E. coli.