فصلنامه پژوهش های صنایع غذایی
سال بیست و هشتم شماره 4 (زمستان 1397)

The objective of the present study was to investigation the effects of the emulsifier diacetyl tartaric acid ester of monoglycerides (DATEM, 0.5 and 1%) and of the enzyme maltogenic α-amylase (MALTO, 0.01 and 0.1%) separately and combined on the quality and organoleptic properties of pan bread. A sample without the addition of emulsifier or enzyme was considered as control bread. The results showed that, compared to control, emulsifier DATEM and α-amylase were effective in reducing density (p<0.05). In this regard, combined effects (emulsifier + enzyme) had better result than individual effect of them. Also, water activities of the different samples were not affected significantly by enzyme and/or emulsifier (p>0.05). Moreover, color results revealed that, compared to control, breads containing enzyme were slightly darker, while emulsifier-containing breads were slightly lighter. Addition of enzyme and/or emulsifier improved the organoleptic quality of pan bread through reducing firmness and increasing flavor, chewiness, and porosity as compared to control samples.

The aim of this work is to investigate the inlet air temperature (140, 160 and 180 °C) and carrier type (maltodextrin vs. Arabic gum) as well as carrier concentration (10, 20 and 30% W/V) on the physicochemical and antioxidant properties of spray dried sweet Marjoram extract. Samples were evaluated for moisture content, water activity, bulk and tapped density, solubility, wettability, hygroscopicity, flowability behavior (Hausner ratio and angle of repose), color indices, microstructure, total phenolic content and DPPH free radical scavenging activity. Powder production yield in the spray drier was also determined. The results showed that powder production yield (21.47-44.62%), moisture content (1.18-2.22%) and water activity (0.106 to 0.206) of powders were significantly affected by the carrier type, concentration and the inlet air temperature. Bulk and tapped density and flowability indices (higher flowability) of powders decreased with an increase in carrier ratio and inlet air temperature. Hygroscopicity and solubility was positively affected by inlet air temperature and negatively affected by increasing carrier concentration. Increasing inlet air temperature and carrier concentration led to deterioration of powder color. Total phenolic content and radical scavenging capacity of spray dried powders were decreased by increasing in air temperature. Increasing in carrier concentration led to an increase in total phenolic content. Microstructure of samples showed that the powders produced with Arabic gum had similar size and higher shrinkage than those produced with maltodextrin. However, the latter had smoother surface.

Gums are polysaccharides that are capable of producing products with high viscosity at low concentrations. In this study, the okra plant gum was extracted with two solvents, water and sodium hydroxide. Extraction efficiency, viscosity, FTIR spectroum and chemical parameters were evaluated to select the optimum extraction. Okra gum extracted with sodium hydroxide compared with okra gum extracted with water, according to the hydrogen bonds between its molecules, had higher viscosity and showed upper stress against flow behavior. This extracted gum had a pseudoplastic or shear thinning behavior with shear rate of 44s-1 and the viscosity value of 11.1mPa.s. The FTIR pattern showed the dominance of oxygen-hydrogen bonds in the compound that represents a lot of parts of galactronic acid in the structure of this gum. Besides, extracting by alkali increased galactronic acid in gum and consequently increased the amount of Hydrogen-Oxygen bonds and the viscosity of the gum. The extracted gum with sodium hydroxide contained alkaline pH (9.75), >10% humidity and high dry matter (90%). Water absorption capacity was 7.9 g water/g material and total ash, protein and carbohydrates were 17.39, 22.80 and 50.464 percent, respectively. Extraction efficiency of gum depending okra pods was 2.39% for water extractingand 5.62% for sodium hydroxide extracting methods.

In this study, the effect of pectin and date syrup on the color indexes, textural and sensory properties of banana pastille were investigated. The variables were including the amount of pectin gum in 3 levels, 0.1, 0.3 and 0.4 % and date syrup in 4 levels, 0, 10, 20 and 30 %. The results showed that with increasing the amount of pectin, b* index increased. With increasing of date syrup also a* and b* indexes increased and L* index decreased. In all samples containing pectin, with increasing date syrup, hardness decreased. Alas hardness decreased with increasing pectin up to 3.0 % but increasing pectin amount till 0.5 % increased. Also pectin led to increase of elasticity, chewiness, cohesiveness and gumminess but decreased adhesiveness. Date syrup also led to increase elasticity, chewiness, adhesiveness and cohesiveness of treatments. The results of sensory evaluation showed that the sensory properties of pastille, the pectin leading to decreased overall acceptance score but date syrup, leading to increased acceptance score of pastille samples. According of the results obtained in this study, using 0.3 % pectin and 20% date syrup for production of banana pastille is recommended.

Medlar (Mespilus germanica L) grows wildly in East Azerbaijan province (Arasbaran). Unfortunately, a few studies have been done on medlar in this area, except in limited cases. This research was conducted based on factorial experiment in completely randomized design with three replications. In this research, the phenolic compounds,antioxidant activity of the peel,pulp of medlar fruit were measured. Also, the extraction solvents were methanol (85%),acetone (80%). The results showed that the methanolic extracts had the highest total flavonoid (415.00,327.83 mg CE.100g FW),total tannin (1132.67,1575.33 mg CE.100g FW) in the both of peel,pulp, respectively. Also, the peel antioxidant activity using FRAP method in methanol,acetone solvents was 1.17,1.13 mg Fe2(SO4)g FW, respectively, which showed no significant difference at 5% probability level. The highest total phenol (762.51,526.12 mg GAE.100g FW) total non-flavonoid (427.01,365.46 mg CE.100g FW) in the both of peel,pulp,antioxidant activity based on DPPH,Fe2+chelating methods (94.87%,52.31%),antioxidant composite index in the peel of fruit (98.86) was obtained in acetonic extracts. In general, the results indicated that medlar fruit are a potential source of natural antioxidants in the part of peel,pulp,acetone is the best solvent for the extraction of compounds containing antioxidant activity.

The genus Rheum L. is one of the most important members of the Polygonaceae family. Rhubarb stems are as rich sources phenolic compounds and antioxidants that have beneficial effects on human health. The aim of this study was to investigate the phytochemical characteristics and antioxidant activity of sixteen genotypes of Rheum collected from different places in Iran. The results showed that location has significant effect (P<0.01) on phytochemical characteristics (including total phenol content, flavonoid content, vitamin C, total tannin, soluble carbohydrate, carotenoid, chlorophyll a and b, TA, pH and TSS). The highest total phenolic content (16.33 mg GAE/g DW) and total flavonoid content (0.37 mg QUE/g DW) were in G3 and G13 genotypes, respectively. Vitamin C was in its highest values in the stems of G13 genotype (28.18mg/g DW). The results showed that location has significant effect (P<0.01) on antioxidant activity of Rhubarb genotypes. Antioxidant capacity (by DPPH) was in its highest values in G13 (91.24%), whereas the lowest capacity was found in G10 (10.80%). In the FRAP method, antioxidant capacity was in its highest values in G8 (15.98 μmol Fe2+/g DW), whereas the lowest capacity was found in G10 (0.14 μmol Fe2+/g DW). Multivariate analysis and clustering revealed three distinct categories of genotypes based on their antioxidant activity and phytochemical traits. These results showed that different genotypes of Rheume specially G1 (Oshnavieh), G8 (Lavasan) and G13 (Saqqez) are promising sources of natural antioxidants and other bioactive compounds beneficial to be used in the food or the pharmaceutical industries.

Powder production from agricultural products that cultivated in large area is important to prevent losses in harvesting time and changing harvested material to valuable product with longer shelf life. The aim of this study was to optimize the drying of watermelon juice in a radiant spray dryer using response surface methodology (RSM). Experiments were conducted in three levels of air temperatures (60, 75 and 90 °C) and three levels of maltodextrin concentration (5, 7.5 and 10% w/v) as an additive material. Dependent parameters were lycopene value, color change, pH, solubility, moisture content, bulk density and antioxidant capacity. Coefficient of determination for prediction of lycopene value, color change, solubility, moisture content and antioxidant capacity were derived 98.70, 94.19, 96.27, 98.50 and 98.71, respectively. With respect to the desired conditions in this research (the lowest change in color and the highest value for lycopene, solubility and antioxidant capacity), the optimized condition with RSM for air temperature, maltodextrin concentration, lycopene value, color change, solubility, moisture content and antioxidant capacity were 79.67 °C, 5% (w/v), 24.84 mg/100g, 37.86, 35.12%, 26.58% (d.b.) and 25.05%, respectively.

The purpose of this study was to investigate the possibility of producing Barbari bread enriched with quinoa whole flour .For this purpose, wheat flour was replaced with 0, 10, 15 and 20% of quinoa whole flour and dough farinograph characteristics including water absorption, dough development time, stability time and degree of softening were evaluated. In addition, porosity, texture, color and sensory properties of bread were also investigated. The results showed that the water absorption and development time significantly (P<0.05) increased in the dough samples containing 10% quinoa whole flour but, stability time significantly decreased (P<0.05) following that degree of softening increased significantly (P<0.05) compared with control. Results of porosity and hardness of breads showed that the control and 10% quinoa whole flour breads had the highest porosity and the lowest hardness among other samples. Investigation the color of bread showed that the bread crust a* in breads containing quinoa flour significantly increased and b* and L* decreased. The bread sample containing 10% of quinoa whole flour and the control samples gained the highest scores of sensory evaluations. So, it is possible to enrichment up to 10% of wheat flour by quinoa whole flour without undesirable changes in the qualitative properties of the Barbari bread.

This study investigated the antimicrobial and antioxidant properties of Citrus aurantium L. essential oil on increasing the shelf life of rainbow trout fillet (Oncorhynchus mykiss) at 0 ° C. Sampling of trout fillets with 0, 0.4, 0.8 and 1.2% of orange essential oil on days 0, 3, 6, 9, 12 and 15, and antioxidant properties, chemical tests (TVN, TBA), PV, FFA, pH) and microbial were investigated. In evaluating the antioxidant property, the concentration of orange (mg/ ml) was 67.6 and 32.71 mg/ml for BHT. The results showed that the pH in the fillet increased from zero to fifteenth day. The volatile nitrogen volumes (except for treatment 2 and 3 on days 6 and 9), free fatty acids and thiobarbituric acid, were significantly different between treatments at different days (P <0.05). The highest and lowest levels of peroxide value were observed in the control treatment at 12.16 ± 0.014 (mg/ kg body weight) on day 12 and treatment at day zero was 0. 862 ± 0.006 (mg/ kg) Fat) was obtained. The total bacterial count in the fillet in the control treatment was higher than the standard level from the 9th to the 15th day and exceeded the limit in treatment 1on the fifteenth day but in other treatments it did not exceed the permitted limit until the fifteenth day (7 log cfu/ g). According to the results, the best shelf-life of rainbow trout fillets was influenced by 1.2% of essential oil of orange leaves on day 9.

Maintaining fruit quality by using physical treatments instead of chemical is the goal of some researchers and is desirable to consumers. In this study, effect of heat treatments on fruit bioactive compounds and antioxidant capacity of two blood orange varieties (‘Sanguinello’ and ‘Moro’) were evaluated at postharvest stage. The fruits were pre-treated in an incubator at 12°C (1 week), 20°C (3 days) and 30°C (2 days) and then were stored in cold storage with 5°C and 85% RH for 60 days. One group of un-treated fruits was also placed in cold storage as control and other group was kept in common storage. Then, their bioactive compounds and antioxidant capacity were evaluated at 0, 30 and 60 days. Result showed that, the total phenol content of treated fruits plup increased up to 30 days of storage as compared with control, but at the end of storage its amount was lower than the control. Total flavonoids also increased in response to heat treatments compared to control. Heat treatments had no significant effect on ascorbic acid and carotenoid contents. While, the anthocyanin and antioxidant capacity were significantly increased compared to the control by heat treatments. The maximum amount of anthocyanin was observed in Moro and Sanginlo varieties with the amount of 3.23 and 1.57 mg / L at 30 °C, respectively. In general, it is possible to use heat treatment (30 °C for two days) to maintain or increase the bioactive compounds of blood oranges during storage.

Kefir ice cream is a fermented dairy dessert made using kefir in the formulation of ice cream. The objective of this study was to produce kefir ice cream by use of low- calorie sweeteners including Rebaudioside A and isomalt in place of sucrose. Treatments A (control, only sugar), B (4 % isomalt and 10 % Rebaudioside A), C (6% isomalt and 20% Rebaudioside A), D (8% isomalt and 30% Rebaudioside A) and E (10% isomalt and 40% Rebaudioside A) were evaluated for physicochemical and sensory properties as well as probiotic bacteria count on 1, 30, 60 and 90 d. The results showed that by adding stevia and isomalt, acidity, viscosity and probiotic bacteria count significantly increased while pH and over run significantly decreased (P< 0.05). During storage, the viability of probiotic bacteria, pH and over run significantly decreased while acidity and viscosity significantly increased (P<0.05). Scores of flavor and total acceptance for treatments D and E were lower than those of other samples. Treatment C (6% isomalt and 20% Rebaudioside A) was selected as the superior one because in addition to having more desirable physicochemical characteristics compared to control sample, it showed no significant difference from control in sensory total acceptance and its probiotic bacteria count was higher than the limit recommended by International Dariy Federation (106 CFU/g).

Encapsulation of hydrophobic nutraceutical compounds such as essential fatty acids in nanocarriers is an effective method for enrichment of low fat products and target delivery of them .In this research production of nano-liposome containing conjugated linoleic acid (CLA ) by thin layer hydration – sonication method and then adding it to low-fat pasteurized milk, have been discussed. Nano liposome containing CLA were prepared by using 50-10 mg lecithin- cholestrol and the size of the particles was 76 nm with a distribution of 0.77. The produced nanoliposome was stable over storage time (30 days) and particles were in nanoscale size. Zeta potential values of particles were negative of nanoliposomes and increasing the time had significant effect on reducing the zeta potential of the samples. Nanoliposome was not opacity, but the increase in the percentage of cholesterol increased the sample turbidity. With the encapsulation of CLA in the nanoliposome, it was protected against oxidation and secondary oxidation products (malondialdehyde). The use of nanoliposomes was effective in maintaining the CLA against the heat treatment (pasteurization) in low-fat milk during storage. With the inference of the results, it can be used to enrich low-fat products by nanoliposome system in the further protection of CLA against environmental conditions.

Barberry fruit is rich in terms of nutritional principles such as antioxidants and phenolic compounds, and its powder could also be considered as an important source of these components. Spray drying is widely used to produce beverage powders. The carrier type and inlet temperature of spray dryer are the most important factors affecting the properties of resulted powder. In this study, the physicochemical properties of obtained barberry juice powder (Brixº 12) using 12% (w/v) maltodextrin with dextrose equivalents of 4-7 and 16.5-19.5 were investigated under two input air temperatures of 130 and 150 °C. Results indicated that at the temperature of 130 °C, with an increase in dextrose equivalent, moisture content decreased and bulk density and higroscopisity increased (P<0.05). Glass transition temperature of produced powders, at inlet temperature of 130 °C increased with enhancement of dextrose equivalent. Scanning electron microscopy presented that the bulk density raised with addition of dextrose equivalent. X-ray diffraction verified the presence of amorphous surfaces about obtained powders. Applying of maltodextrin with higher dextrose equivalent caused reduction in total anthocyanin content. The results of colorimetric assessment revealed that with an increase in dextrose equivalent, a* index decreased (P<0.05). Generally, the produced powder using fewer dextrose equivalent, under inlet temperature of 130 °C had better physicochemical characteristics.

Historically bread has been a popular food for many generations. Bread is the most consumed food around the world, therefore the regulatory offices must be held accountable for ensuring the safety and quality of bread production. The addition of blankit (sodium dithionite) and baking soda to bread is a form of fraud and irresponsible manipulation that has found its way into bread production methods, whether deliberate or not. The addition of the raising agents such as blankit (sodium hydrosulfite) and baking soda, even in very small quantities, has been known to have negative impacts on the health of people. Therefore, there have been attempts for detection of these types of raising agents in bread using qualitative methods which have not been successful for detection of the small amount of blankit (sodium dithionite) and baking soda in bread dough. Therefore, the development of sensitive and accurate methods for detection and quantification of these types of raising agents in bread is an unmet need. Here we purpose to develop a suitable and valid method for quantification of trace amount of blankit in bread dough. We used standard # 2628 method of The Institute of Standards and Industrial Research of Iran for quantification of these raising agents and made slight modifications (A freshly prepared rosaniline solution was used and the quantification was done on bread dough samples instead of the baked bread). The bread dough samples were spiked with blankit standard solutions and then the samples were quantified at 560nm by spectrophotometry. The R² for the calibration curve was 0.999 indicating the linearity of the developed method. The recovery percent in accuracy factor for two spiked samples were found to be 89.805 and 103.3, respectively. The sensitivity of the method for 3 selected samples were 0.329, 0.242, and 0.203 ppm. The LOQ was calculated to be 0.05 ppm for the developed method. These data indicate that the developed method is a valid and sensitive method for quantification of blankit in bread dough.