مجله علوم و صنایع غذایی ایران
سال شانزدهم شماره 9 (پیاپی 94، آذر 1398)

Drying foods, such as freezing methods and hot air, are not ideal and reduces the nutritional value and is also expensive and is used only for high value food. In this research, drying with supercritical fluid of carbon dioxide was investigated to remove moisture from the figs. In the drying process with supercritical fluid, the structure of food products is maintained during drying. The design of the experiment was carried out in a factorial arrangement using Design Expert software and analysis variance table to determine the effect of three pressure parameters, temperature, and time to measure the removal rate of moisture. The calculated factorial model was meaningful and able to select the best drying parameters. In optimum conditions, the highest yield (78.109%) with the desirability of 0.992 at 20 MPa, 60 °C and 120 minutes duration. The results showed that the drying of figs during the whole drying period is carried out at the downstream stage, which indicates that the drying of these materials, the internal moisture control, controls the rate of drying and mass transfer. In this study, by solving the second Fick's law and in the range of pressure and temperature tested, with the assumption of the spherical of the fig using the Crank equation, the amount of moisture diffusion coefficient between 4.51× 10-10 and 0.18 × 10 -10 m2/s were obtained. The fig's drying rate was also calculated. Increasing temperature and pressure caused to increase the drying rate.

Some plants have antioxidant compounds and antimicrobial properties and can be used as fractional compositions in the industry. This study aimed to investigate the radical scavenging and antimicrobial properties as well as the determination of the compounds in the seed extract of Securigera securidaca. The plant seeds were extracted by maceration method using ultrasound (50 Hz) and dried extract in this study. Then, the compounds were identified by GC/MS device and the radical scavenging capacity was determined by DPPH. The antimicrobial properties of the extract were determined by disc-diffusion method against Escherichia coli, Listeria monocytogenes and Candida albicans strains. Fourteen (14) compounds were identified, containing 98.58% of total extract compositions, and the highest percentage was related to Mome Inositol (30.55%) and cis-9-Octadecenoic acid (20.44%). The highest radical scavenging capacity was observed at the concentration of 600 ppm of extract (91.6%). Different concentrations of the extract rather than the concentration of 0.25 mg/ml inhibited L. monocytogenes and all concentrations of extract had inhibitory effect on E. coli and the most effect was related to the concentration of 0.5 mg/ml (12.98 mm). None of the concentrations had an inhibitory effect on C. albicans. The results showed that the extract inhibitory effect increased on the strains effectively by increasing the concentration of extract. The plant extract can be used in the nutraceutical industries due to its appropriate antioxidant activity and antimicrobial properties.

In this project, low-fat composite (wheat-millet) cup cake was produced. Fenugreek seed gum (0.25, 0.50, 0.75 and 1%)  was used as a fat  replacer in levels of  0, 25, 50, 75 and 100 %. specific gravity and  consistency of batter and moisture, specific volume, porosity, firmness (2 hours and 1 week after baking), crust color and sensory properties of chiffon cake were measured. The sample containing 0.25%  Fenugreek seed gum had the lowest specific gravity and firmness and the highest  specific volume, porosity, L* value and overall acceptability score. Also, the result showed the technological and sensory properties of sample containing 0.25% Fenugreek seed gum was similar to control. Moisture and a* value were increased and b* value was decreased by increasing Fenugreek seed gum. Finally, the removal of 50% of oil in chiffon cake formulation was performed successfully.

Celiac disease is an autoimmune gastrointestinal disorder that occurs in sensitive individuals upon the consumption of gluten. It is one of the most common genetic abnormalities in the world, which is triggered during the process of digestion of gluten protein and the only way to treat it is to go on a gluten-free diet. The purpose of this research was to apply methods of Response Surface Methodology (RSM) and Central Composite Design (CCD), and to study the effect of independent variables including various concentrations of xanthan gum, guar and carboxymethyl cellulose gum (0, 0.3, and 0.6%) on physicochemical, rheological and organoleptic properties of gluten-free biscuits based on rice flour. The equations achieved through the examinations revealed that independent variables had significant effect (P < 0.05) on the parameters. Among the studied parameters, the effect of xanthan gum concentration was found as the most efficient variable. The results also showed that increasing the concentration of the gum would increase the moisture content, total ash, color changes, and overall acceptability of gluten-free biscuits, while decreasing their hardness and Spread Ratio. In general, the optimization of the researched variables showed that using 0.6% xanthan gum, 0.3% guar gum and 0.13% carboxymethyl cellulose gum would result in production of desirable sample products that would be similar in qualitative characteristics and overall acceptability to the wheat flour biscuits, and could be used for celiac patients’ diet programs.

The aim of this study was determining the concentration of heavy metals as Lead, Cadmium and Tin in canned peas, with pre-treatment by 5 and 10-minute blanching and using citric acid, acetic acid and phosphoric acid at concentrations of 0, 0.25 and 0.5%. The samples were manufactured and sealed commercially. The evaluation of mentioned heavy metals was carried out using by flame photometric method. The response surface method was carried out in central composite design, and data analysis was done using Design Expert software. The effect of the dependent variables in quadratic model is evaluated. According to the results, the highest levels of Lead, Cadmium and Tin were 0.43, 0.61 and 87 parts per million respectively and the lowest was zero, 0.14 and 10.43 parts per million, respectively. The results showed that increasing the blanching time reduced the lead, cadmium and tin amounts at 1% level. On the other hand, increasing the concentration of acetic acid, citric acid and phosphoric acid to its highest level would yield the best results to achieving the lowest amount of these elements during blanching.

Packaging films are one of the common ways to maintain the quality of food and agricultural products. The effect of PVC and HDPE packaging films, storage and temperature on some mechanical properties, including: the firmness force, yield strain, energy of rupture and modulus of elasticity and also, the viscoelastic behavior of the strawberry fruit was investigated. The mechanical test and relaxation test were done using a texture analyzer. In this study, the stress versus time graph was plotted and three-component Maxwell model coefficients were obtained. According to the results of this study, the use of these films had a positive impact on the yield strain. On the other hand, products in the packaging films were able to store products until the 40th day. In this study, the firmness force of HDPE packaging fruits in 4℃ and 20℃ from 2.17 to 1.10 N, 2.16 to 1.85 N, decrease respectively, during storage. The results show that Maxwell model (RMSE<0.6818 and R2 >0.9158) fits the experimental data. Also, with a retention time, the elastic component of the model is relatively reduced and the application of the packaging prevents the decrease in relaxation time.

The use of sourdough in bread formulation affects the physicochemical properties of the final product leading to enhancement of the nutritional value and reduction of waste. Therefore, in this research, flours obtained from two different varieties of wheat including Mehregan as a hard and strong variety with high protein content and Sardari as a soft and weaker wheat with lower protein content, both with different extraction rates (whole flour, 88 and 77%) were used to prepare sourdough. After preparing the baguette sample, the physicochemical and sensory properties of the products were evaluated using a completely randomized factorial design (P≤0.05). The results indicated that higher amounts of organic acids, i.e. lactic acid and acetic acid were produced in the sourdoughs obtained from Mehregan compared to those made from Sardari which in turn led to their higher acidity and lower pH. Moreover, the breads made from Mehregan flour possessed higher moisture content, greater specific volume and porosity and lower hardness than the samples produced from Sardari variety. The increase in extraction rate for both flour types affected the aforementioned attributes the same way as did increase in protein content. The findings showed that increase in protein content (Mehregan vs. Sardari) and/or extraction rate of the flour enhanced the color parameters of L* and a* but the b* was not significantly influenced by either factors. Having softer and more porous texture, more desirable appearance and more delicious flavor, the sample made from Mehregan flour received higher total sensory scores than Sardari samples. Likewise, the increase in extraction rates for both flour varieties were accompanied by higher sensory acceptability. Hence, the baguette bread obtained from Mehregam with 100% extraction rate was introduced as the best sample.

The mechanical properties of fruit are one of the most important determinants of standards for designing, transforming, processing, and packaging systems. One of the methods for changesdemonstraction in the internal structure of fruits during storage is to perform stress relaxation tests in different predetermined strains. Therefore, the purpose of this study was to investigate the orange compression behavior in quasi-static mechanical loadings by performing stress-relaxation tests of samples at predetermined levels of strain and modeling the Maxwell and Peleg method and comparing it with image processing method. In addition, in this study, cross-sectional area changes were measured during loading by image processing. The modulus of elasticity in the image processing method, the Maxwell model and the Peleg model on days 0 to 9 increased from 3.91 to 4.5, 3.6 to 4.53 and 2.7 to 3.45, respectively. which in spite of increasing trend there was no significant difference between them Since, no significant difference in the output of these two models (Maxwell and Peleg) was observed Peleg with the less number of elements (only two constants) was preferred compared to Maxwell method

In this study, the electrostatic interaction between quince seed mucilage with whey protein isolate was investigated. For this purpose, turbidity analysis, zeta potential and yield of coacervation were used to determine the optimum complex coacervation conditions. Then, the properties of the coacervates were evaluated by appearance, SEM and light microscopy. The turbidity reached its maximum value of 2200 NTU at 70:30 ratio of protein:mucilage. The highest yield of coacervates (80.67%) was obtained at pH 4. The results showed that the best coacervation conditions were obtained at 70:30 ratio and pH 4. Surface morphology and light microscopic images showed that the coacervate particles are a collection of smaller particles. The SEM image also showed that these particles had a heterogeneous appearance after drying. These types of coacervates can be used as texturizer, carriers of bioactive agents and fat substitutes in food and pharmaceutical products.

Nowadays, consumption of non-dairy-based desserts with a variety of flavors compounds is growing, that are consumed by different age groups due to nutritional value and organoleptic properties. The objective of this study was to investigate the optimization of non-dairy dessert formulations based on almond milk. Additives in three levels of sugar (2, 3, and 4%), pectin (0.5, 0.6 and 0.7%) and gelatin (0.4, 0.5 and 0.6%) were used to produce desserts. Then, the physicochemical properties of the produced dessert including pH, syneresis, viscosity, texture and colorimetric parameters of the produced dessert were measured. The results showed that by increasing the percentage of pectin and sugar, the index L* decreased, by increasing the percentage of gelatin and pectin, a* decreases and by increasing pectin percentage, b* decreased and the effect of gelatin increase was not significant. Increasing the percentage of gelatin and pectin in all levels of sugar has increased the stiffness of dessert samples. By comparing the average values of the stiffness of the dessert texture produced at the fixed levels of gelatin and pectin, it can be concluded that sugar content has a significant effect on the stiffness of the dessert texture after production, and increasing the sugar content, pectin and gelatin increases the stiffness of the texture. In all levels of sugar, the viscosity of desserts increased with increasing gelatin and pectin percentages. By increasing the percentage of gelatin and pectin, the pH decreased. The addition of gelatin and pectin, especially in high concentrations, significantly reduced syneresis.

Yogurt is a fermented dairy product, which is a popular product throughout the world and has positive effects on public health, due to its nutritional properties. Aloe vera extract is a kind of vegetable derivative, which has high nutritional value and antibacterial properties. In this research the effects of Aloe vera extract (0.5, 1, 1.5, 2% w/w) addition on the textural (syneresis), chemical (pH, acidity), viability of yoghurt probiotic microorganisms, yeast and mold, antioxidant properties and sensorial attributes of stirred probiotic yogurts were investigated during the shelf life (1st, 7th, 14th and 21thday of production). The results showed addition of Aloe vera extract decreased the pH value and increased acidity but decreased syneresis. Bifidobacterium and Lactobacillus viability increased with Aloe Vera extract addition but yeast and mold counts decreased. The addition of Aloe vera extract increased antioxidant properties of yoghurt. Sensorial analysis indicated that panelists preferred yogurt samples with low Aloe vera extract rates. However, higher rates of Aloe vera extract affected the flavor and overall acceptability and lowered their panelist scores. During time, pH decreased and acidity and syneresis increased. Overall, it was concluded that the best treatment from all aspects, was 0.5% Aloe vera extract.

In this research, physicochemical and antioxidant properties of two varieties of lemon (Cook Eureka and Khoushehi) were evaluated during two years by sampling from October 17 to November 16, every 10 days (four times) from trees and at the end of shelf life period. The results showed, generally, the size and volume of fruit of Cook Eureka was large and Khoushehi lemon was small. The fruit weight and juice percentage in Cook Eureka did not change significantly (p<0.05) during harvesting time and shelf life. The TSS/TA ratio also increased during ripening and shelf life, with the exception of the Khoushehi fruits which harvested on November 16. Although the technology index in Cook Eureka was not significantly change during harvesting times, but the peel thickness of Khoushehi fruits decreased during shelf life. In general, the values of L*, a* and b* color indices in both varieties and experiment were high from first to last harvest times. Also, amount of Chroma and CCI showed an increase pattern during shelf life. Fruits picked at the last harvest (Nov. 16), which had the highest amount of vitamin C (28.31 mg/100gFW), also had the highest vitamin C levels at the end of shelf life (42.64 mg/100gFW). Totally, the total phenol and antioxidant content of fruit were increased during shelf life period in both varieties.

Today, with the increasing population of celiac patients worldwide, producing and improving the quality of gluten-free products for celiac patients is one of the major challenges in the food industry. Celiac disease is a type of autoimmune gastrointestinal disease caused by intolerance to gluten protein and currently, the only way to treat it is to use a gluten-free diet. Gluten removal results in major problems including poor quality of mouth feel and poor taste of the product. Finding a suitable alternative to gluten is one of the biggest technological challenges in the production of gluten free products because of the importance of this protein in creating a suitable texture and appearance in the product. As a result, researchers and manufacturers are trying to promote gluten-free products by finding the right way and produce products of similar quality to wheat flour products. The aim of this study was to review different process technologies to improve the quality of gluten-free products. These process technologies include the use of conventional methods such as gums and proteins, biotechnological methods such as the use of enzymes and sourdough and modern methods including thermal and non-thermal treatments in producing gluten-free products.

Fried foods are favored by consumers because of the crispy crust, desired flavor and color, but these properties are accompanied by some undesirable effects to the consumers due to the considerable amount of oil absorption during frying process. Therefore using methods for decreasing oil uptake, while retaining the desirable features seem necessary. In this research, the effects of edible coating of locast bean, Avicennia marina seed gums and mixture both on percentage of coating, moisture content, oil uptake and organoleptic properties of potato strips were evaluated. The results showed that coating percentage and moisture content increase whereas oil content of potatoes decrease with increasing in gum concentration. Coated samples had higher transparence and yellowness than control samples. Highest percentage of fat content was in control samples. Samples these coated with Avicennia marina seed gum 1.5% and mixture coating 1% respectively were best samples in organoleptic properties. The use of coating in fried potato strip can improve the nutritional value and organoleptic properties of final product.

In this research, carrots were first cut into equal pieces and then subjected to different treatments at different levels. The voltage levels were at 40, 60 and 80 volt in ohmic pretreatment and at 3, 5, and 7 minutes. The parameters studied in the blanching pretreatment included time, with different levels of 5, 10, and 15 minutes. Immediately after pretreatment, samples were dried in microwaves at 360, 600 and 900 watts. Finally, for each case of microwave dried and pretreated samples and their different levels, the energy efficiency values and their lost energy were calculated. According to the results, in the majority of cases, we see that increasing the amount of microwave power increases the energy efficiency, and subsequently, the lost energy decreases, so that the maximum value was 15.8797%. In the study of the effect of voltage in the ohmic pretreatment, a similar result was obtained, with the highest energy efficiency of 15.7061%. Also, in evaluating the effect of time parameter in ohmic pretreatments, it was observed that with increasing pretreatment time, the amount of energy efficiency was also increased and the energy lost was reduced, so that the highest amount of energy efficiency and the lowest amount of energy lost were respectively 15.7409% and 8.2358 MJ were measured.