نشریه نوآوری در علوم و فناوری غذایی
پیاپی 15 (بهار 1392)

In this study, the effect of low fat and low salt formulation by replacing with calcium chloride, magnesium chloride, potassium chloride and low acyl gellan gum on texture of sausage were simultaneously investigated. The results suggested that after reducing salt and fat content through replacing with the gellan gum and dicationic salts led to an improvement in the texture and moisture of the samples. By adding magnesium chloride, texture of the samples improved. On the other hand, by adding calcium chloride the texture of the samples was deteriorated. It seems the dicationic salts level in formula led to a decrease in water holding capacity of the low acyl gellan gum. It can be assumed that textural properties differences between the samples were due to the effect of the dicationic salt level on extracted myofibrillar protein and its solubility, and low acyl gellan gum gelation properties. By adding magnesium chloride and the gellan gum in low salt and fat meat product, negative effect of reducing salt level would be compensated.

Nowadays, increasing demand for developing natural component in food products besides the potential risks of artificial antioxidant for human health has cause many researchers to substitute natural antioxidant in food stuffs. Turmeric is one of those plants which owns unique functional properties and has several applications in traditional food and drug industries. In this study, in order to introduce a natural antioxidant for food industry, the active substance in turmeric rhizome (curcumin) was extracted by maceration method and identified with thin layer chromatography (TLC) and nuclear magnetic resonance (NMR).To evaluate the antioxidant efficiency of curcumin, the soybean oil with no antioxidant was used as a food model and its fatty acids profile was determined by gas chromatography (GC). Then the effect of various concentration of curcumin (0.012,0.016,0.02%) was compared with TBHQ (0.012%), α- tocopherol (0.02%) and blank (oil without antioxidant) in two temperatures (25 and 55 ºC) under dark and light conditions, during 90 days. The result of TLC analysis showed that the extracted curcumin contained bisdemethoxycurcumin, demethoxycurcumin. In addition, NMR spectra corroborated the chemical structure of curcumin. GC analysis showed that linoleic acid was the major fatty acid of soy bean oil and the other fatty acids were in the standard range. The results showed that increasing curcumin concentration significantly leads to decreasing oxidation rate. Peroxide value in treatment with 0/02% curcumin was the same as treatments contain 0/02% α- tocopherol and 0.012% TBHQ in 25 ºC. Data obtained from study of light effect in oil samples showed that in oil contain 0/02% curcumin, Oxidation rate in dark were the same as Oxidation rate in0/02% α-tocopherol and 0.012% TBHQ. Also in all samples, peroxide values increased in light and high temperature but light did not show any effect on acidity of samples (p 0/05) and iodide value of all samples were constant.

The aim of this study was to investigate the effects of adding orange fiber on physicochemical, rheological and sensory properties of strawberry yogurt using response surface method (RSM). The amount of fiber was in the range of 0-1.2% with the storage time of 3-29 days. The results showed that by increasing fiber amount, the viscosity and dry matter increased and the final product syneresis decreased significantly (P<0.05) but acidity and pH was not significantly affected (P>0.05). The amount of syneresis and acidity significantly increased during storage, but pH and viscosity decreased (P<0.05). Also, increasing the amount of fiber content increased yellowish spectrum (+b* parameter) while the rate of Lightness (L*) of the samples (P 0.05) decreased. Sensory evaluation results showed that by increasing of fiber amount, the score of color, odor, taste and overall acceptance decreased but the gained scores were at the good range and acceptable. According to the empirical models obtained by response surface methodology the relation between different variables were suitable. Finally, the optimum conditions for production of strawberry yogurt containing orange fiber were obtained using 1.2% fiber in a storage period of 16 days. The final product viscosity was 3519 cp, syneresis 28.49%, dry mater 25.24% and overall acceptability score was rated 4.75 counts out of 7.

Grape juice concentrate is the local product of grape growing regions in Iran and is mainly extracted from the rotten grape of the late days of the year. In order to study the effects of clarifying agents on the quality of prepared grape juice concentrate, an experiment was conducted using the complete randomized factorial experimental design. The first factor was types of clarifying agents in 6 levels including syrup soil, bentonit, silicasol, gelatin bentonit, gelatin-silicasol, gelatin-bentonit-silicasol and the second factor was the amount of clarifying agents in 3 levels and 3 replicates. Statistical analysis of the results showed that the increase of the amount of syrup soil decreases the level of acidity of grape juice concentrate and increases its pH. But the addition of other filter-aid like bentonit, silicasol and gelatin didn’t have any significant effect on the level of acidity and pH. Using bentonit and silicasol comparison with syrup soil increase of transparency and decrease of turbidity significantly. The addition of gelatin to bentonit and silicasol in comparison to bentonit and silicasol alone decreased turbidity and increased transparency of samples significantly. Treatment of gelatin-bentonit-silicasol has the highest amount of transparency (89.467%). The lowest amount of turbidity (8.483%) was considered as the brightest and clearest treatment among all of samples. The resulting grape juice concentrate had no adverse changes of pH, acidity, protein, sugar, ash, brix, total solid as the most important quality indices. Finally, 2%gelatin-4%bentonit-7%silicasol treatment was chosen as effective treatment for clarification of grape juice concentrate.

This study was conducted to investigate the combined effect of applying herbal cysteine protease and solutions of sodium tripolyphosphate (STPP) to beef. 3×3×3 cm chunks of beefs were marinated in two stages. In the first step, they were marinated in 20ml pineapple extract, kiwifruit, ginger and the second step had been done with 20ml of 0.25% and 0.5% of STPP. In both stages, the chunks of beef were stored in refrigerator at 4±1 °C for 24 hours. After 48 hours chilling, meat chunks were immersed and cooked in water bath at 90±4 °C and their shear force values, pH and cooking loss were studied. A significant decrease in shear force were observed in all enzyme-treated samples compared to control. The effect of phosphates on shear forces values were not significant compared with control. The results showed that cooking loss increased significantly by increasing in percentage of phosphates and decreased significantly (p≤ 0.05) compared with controlled sample. The rate of pH of samples (pH rate of samples) depends on inherent pH of extracts and increasing in percent of sodium tripolyphosphate led to a significant increase in pH of the treated samples. The results obtained in this experiments clearly indicate that best results were achieved by applying kiwi fruit extract with 0.25% sodium tripolyphosphate.

Tuna canning processing generates solid by-products, constituting 50- 70% of the original raw material. The main aim behind the hydrolysis of fish byproduct is to achieve a valuable material with high efficiency and quality. The objectives of this study were to optimize process conditions of fish proteins hydrolysate (due to its various application in food industries).Enzymatic hydrolysis of Yellow fin tuna head has been conducted by Alcalase with three replications using an experimental design. The hydrolysis conditions were (temperature: 55ºC, pH= 8.5, enzymatic activity 35Au ⁄ Kg and three consecutive time of 10, 20 and 30 minutes). The efficiency of protein production, degree of hydrolysis, the peptide chain length and electrophoresis pattern were evaluated. The results showed that increasing in time of protein hydrolysis causes an increase in efficiency of protein production and degree of hydrolysis and decreasing of peptide chain length. Among the above three mentioned times, 30 minute, with highest degree of hydrolysis is considered the best time for Alcalase enzyme. The most recovery of protein and degree of hydrolysis is related to first stage of hydrolysis (p˂0.01). In a study pertained to Electrophoresis pattern by SDS- PAGE, molecular weight of the most proteins hydrolysate had been about 12 KD.

In this research, the effects of Ultraviolet radiation (UV-R) and Monochromatic lights (red and blue) on the growth rate, protein content and fruit body formation in Pleurotus florida are analyzed in a period of 60 days. SPSS and Excel software were used to analyze the results and the Duncan test was used to compare the data average. The research has shown that there are vegetative growth and morphogenesis rates difference in various treatments where maximum rate is seen in red light treatment (5. 58mm per day) and minimum (3. 03mm per day) in Ultraviolet treatment (UV=8h). The fruit body productive pins that show the morphogenesis rate of of Pleurotus florida are also observed in the treatment of blue, red and UV light. The blue light has a significant impact on the fruiting period where the first pinhead was seen 26 days after cultivation in this treatment. The results of protein measurement also depicted the difference of quantity in various treatments in a way that the minimum amount of protein was observed in the UV treatment and control one and the maximum was seen in the blue light treatment. The amount of protein the enhanced significantly in the blue light treatment and reached from 59. 50 mg. g-1 dw in the control treatment to 142. 08 mg. g-1 dw. One of the other observed changes was an increase of mycelium pigmentation in some treatments. This phenomenon was also seen more in the UV treatment and less in the blue light one.

Recently, Using natural coatings have been replaced with chemical coatings by most consumers all over the world. In this research, some qualitative properties of Thomson orange were evaluated using Chitosan edible coating (at 0.5, 1 and 2 % concentrations) and chemical coating of fungicide (Ortho Phenyl Phenol) was compared to uncoated samples during three months of storage. Orange samples were kept in cold storage at temperature of 6°C with 85-90% relative humidity. Also pH, titrable acidity of orange juice and weight loss percentage were measured during storage. The results showed that chitosan coating with 2% concentration has reduced weight loss of orange juice compared to other coatings; furthermore, having higher pH than the rest of samples, it has enhanced fruit resistance against fungal attacks. Overall, it has also preserved the fruit quality during storage time.

Dairy products contain lactic acid bacteria. Preparation of traditional foods with dairy products have a long history. The aim of this study was to investigate the antagonistic properties of lactobacillus isolated from Iranian traditional food samples. In this study, after calculating the presence of lactobacillus in traditional foods, the antibacterial properties of isolated strains against Staphylococcus aureus and Escherichia coli were studied by dot culture and disc diffusion methods. The isolates tested (70%) were capable to inhibit the growth of bacteria indicators. Lactobacillus casei and Lactobacillus plantarum showed the biggest zone of inhibition against the indicator strains by disc diffusion method. The antibacterial activity observed can be attributed to bacteriocin production by lactobacilli. Considering the source of the isolated lactobacilli strains, purification of bacteriocin from these strains can be used as probiotic or biological preservatives in food industry.

Inulin is a fat – replacer added in bakery products to increase the fiber and decrease the calorie content. In this research, effect of the replacement with Inulin was studied. Physical properties of batter such as specific volume, density and rheological properties of batter such as viscosity were evaluated. Results showed no significant differences in the density and specific volume between control batter and batter prepared with 20% fat-replacer level. Increasing Inulin level in the batter showed there were significant differences in the physical and rheological properties. Batter prepared with 20% fat-replacer level showed lower viscosity than that of control. Evaluating the effect of inulin on the textural attributes showed cake prepared with 20% fat – replacer level was as firm as the control sample. Increasing the level of replacer showed the hardest texture. The hardest texture was observed in the cake prepared with 60% fatreplacer.

In this study the researchers, compared physicochemical properties and juice clarification processes of two native varieties of Iranian White mulberry name Bukharaei (seedless) and Mikhce. Two varieties of berries, about the same age were selected from two trees in the garden adjacent to each other. Therefore, the same climatic conditions, irrigation and soil fertilization were considered. The results of this study showed that Bukharaei varieties of mulberries had higher moisture, sugar, pH and Brix but less acidity and minerals compared with others while the taste of Bukharaei varieties was better. Comparison of some clarifiers such as Silicasol, Bentonit, Tannic acid, Pectinase and  -amylase, showed that tannic acid could remove haze and turbidity of white mulberry juice significantly. Combination of enzymes - clarifier aid and correcting acidity can be an effective optimization method to clarifying of white mulberry berries juice.

Achieving optimum drying conditions can affect the processing time and improvement of raisin quality. In this research, drying quality of Black currant grape in two-step temperature and different pretreatments was studied. Drying Was accomplished in two steps: The first step involved temperature at four levels of 50,60,70, and 80 ºC and Then followed the second step in which step which samples were placed at two temperatures. In this step, samples were placed at 80 ºC and while moisture content was reduced to 50, temperature was reduced to 70, 60 and 50 ºC. Four pretreatments including hot water, %5 potassium carbonate, %0.4 olive oil, %0.5 sodium hydroxide(caustic soda) and without pretreatment were performed. The results showed that some factors such as temperature and pretreatment have significant effects on browning index, dehydration ratio and shrinkage and only temperature factor was significant on acidity. Raisins dried at two-step temperature by changing the second step’s temperature to 60ºC in pretreated of %5 potassium carbonate, %0.4 olive oil and %0.5 sodium hydracids have better quality. Also raisins dried at 70ºC and pretreated in %0.5 sodium hydracids have better quality.