فصلنامه پژوهش های صنایع غذایی
سال بیست و پنجم شماره 1 (بهار 1394)

Due to importance of legumes proteins on human health, in this study the effect of red lentil flour and red grape concentrate on Bifidobacterium bifidum viability, physicochemical and sensorial properties in set yoghurt was examined during storage, using response surface method (RSM). Amounts of red lentil flour, red grape concentrate and storage time were in the range of 0-5%, 0-20.2% and 1-25 days, respectively. The results of statistical analysis showed that with increasing of red lentil flour up to 2.5% level and red grape concentrate to 10.1% level, Bifidobacterium bifidum viability increased significantly (P<0.05). As well, with increasing of lentil flour and grape concentrate, the amount of moisture content of samples reduced significantly (P<0.05). Acidity increased by addition of lentil flour up to 2.5% level; whereas higher amounts of flour caused a reduction of acidity. The higher the concentrate, the lower was the acidity (P<0.05). Results of colorimetric assessment showed that, red grape concentrate decreased L* and b* values and increased a* value significantly (P<0.05). Furthermore, increasing in red lentil flour to 2.5% level resulted significantly enhancement of b* value, but in more amounts, caused b* value to decrease. With respect to the results of sensorial evaluation of samples, addition of lentil flour caused an improvement effect on consistency and grape concentrate caused also better flavor in yoghurt samples, significantly (P<0.05). In conclusion, using of 2.439% of lentil flour and 15.34% of grape concentrate with storage period of 13 days was determined as optimum conditions.

Fishes are a good source of dietary protein supply with the higher nutritional value than other foods and are considered a healthy food. In this research, two species of tuna fishes (Euthynnus affinis and Katsuwonus pelamis) were selected for evaluation of nutritional and some of physicochemical properties before and after processing for checking of nutrients in processing time and after it. In this study, some chemical properties such as fat, protein, ash, moisture, pH, grass energy, peroxide value, acid value, iodine value, and refractive index were evaluated. Results showed that fat levels were increased after processing for all samples but ash and protein levels were decreased (P<0.05). Moisture level was decreased for Euthynnus affinis after processing and during storage time but it was not changed in Katsuwonus pelamis. The obtained results showed that grass energy level after 3 months ofstorage after processing was higher particularly in canned Euthynnus affinis than in canned Katsuwonus pelamis. Total energy in Katsuwonus pelamis after 3 months of conservation was 293.4 kcal/100g whereas energy level in Euthynnus affinis after 3 months of conservation was 376.58 kcal/100g. Euthynnus affinis oil had significantly (P<0.05) higher amounts of peroxide and acid value and lower iodine value compared to Katsuwonus pelamis oil. In conclusion, the obtained results showed that canned Euthynnus affinis (after 3 months conservasion) had significantly (P<0.05) the highest amounts of peroxide and acid values and the lowest level of iodine value compared to canned Katsuwonus pelamis (after 1 month conservasion).

The objective of this work was to investigate the effects of sonication on turbidity, viscosity, particle size distribution and total phenol of carrot juice. Carrot juice samples were sonicated according to a D-optimal design response surface with three factors of sonication temperature (25, 37.5 and 500C), sonication time (10, 20 and 30 min) and sonication power (350, 400w) at a constant frequency of 24 kHz. The results showed that ultrasound temperature (P<0.01) and time (P<0.01) significantly increased the turbidity of carrot juice samples. Also a significant change in particle size distribution was observed in sonicated juice due to cavitation effects. These resultes indicated that the cloud stability of sonicated carrot juice depends not only on pectin methylesteras inactivation but also on particle siz reduction. The highest particle size was observed in heat-treated juices due to heat coagulation of the colloidal materials. Sonication could not make significant alteration in the apparent viscosity of juice at different shear rates ranging between 0.1 and 100s-1, which indicated that the ultrasound or heat treatment juice followed the Newtonian flow behavior. However, the viscosity of heat-treated juice was significantly higher than untreated and sonicated samples. Ultrasound time significantly decreased the total phenolic contents of sonicated samples (P<0.01) but, significant difference was not observed between sonicated and heat-treated or untreated samples. These results suggest that, sonication with mild heat could used to obtain carrot juice with low Particle size and high turbidity, high viscosity and good retention of phenolic component.

Effect of packing in nano composite-based packaging prepared via blending polypropylene (PP) with nano-Ag on quality attributes and postharvest life of fresh-cut nectarine (cv. Red Gold) during storage at 0-1 0C with 90-95% RH for 21 days was studied. Decay incidence, weight loss, total soluble solids content, total acidity, vitamin C content, malondialdehyde, polyphenol oxidase activity and browning index were evaluated during and at the end of storage. Nano-packaging significantly reduced decay extension, polyphenol oxidase activity, browning index, malondialdehyde accumulation and weight loss and also retained fruit total acidity, total soluble solids and vitamin C content. Total soluble solids content of control fruit was significantly higher than that of nano-Ag packed fruits. The results indicated that the use of nano-AG active packaging may be introduced as an effective technology in order to maintain the quality and increase the postharvest life of “Red Gold” fresh cut nectarines.

Effect of, citric acid, sodium potassium tartrate or calcium chloride addition on water vapour permeability, oxygen transmission rate, and mechanical properties of hydroxypropyl cellulose films at different relative humidities were studied. Water vapor permeability, oxygen transmission rate, and mechanical properties of hydroxyethyl cellulose films were determined. Analysis of film surfaces and thermal properties of the films were also performed. Hydroxypropyl cellulose films containing 15% citric acid resulted in smaller water vapor permeability and oxygen transmission rate in comparison with hydroxypropyl cellulose films at the three relative humidities. The films containing citric acid were more flexible than that of the films containing calcium chloride or sodium potassium tartrate.

Thermal treatments were effective on rheological and textural properties of hydrocolloid solution and can change functional and color properties. In this study, under optimum conditions, Basil seed gum were extracted and dried. Then, concentration of 0.2 % (w/w) of gum were prepared to determine rheological and color characteristics and concentrations of 3, 4% (w/w) for of textural properties, and then subjected to freezing treatments. Apparent viscosity and flow behavior were measured at 25 °C by Brookfield rotational viscometer and fitted with power law, casson and bingham models. Compression tests were conducted by using a Texture Analyzer and characteristics such as hardness, consistency and adhesiveness were measured. Power law model well described non-newtonian pseudoplastic behavior of Basil seed gums in all conditions. Results showed the resistency of Basil seed gum to freezing and defrosting and in the some cases, conversion of water to ice leads to an increscent in molecular association and improved their rheological and textural characteristics and with decreasing in temperature from 25 ºC to -18 ºC, viscosity increased from 0.00512 to 0.00524 pa.s (shear rate 245 s-1). The highest hardness, adhesiveness and consistency value of Basil seed gum gels (3%) were observed in sample treated at -25ºC for 24 h, 22.1 gr 22.87 gr/s and 72.74 gr/s, respectively. Therefore, Basil seed gums can be suggested as a textural and rheological modifier in formulation of foods exposed to freezing treatments.

In this paper after the preparation of polyethersulfone (PES) membrane by immersion precipitation method, the treatment of wastewater of milk powder production has been investigated by using this membrane. The investigation of influence of membrane morphology on the flux of obtained membranes and removal of COD and TDS of this wastewater is main purpose of present research. Scanning electron microscope has been used to study the structure of obtained membranes. In order to evaluate the performance of prepared membranes in the wastewater treatment, the values of flux and rejection of COD and TDS have been determined. A surfactant as additive has been used to improve the hydrophilicity and permeation of membrane. The effect of concentration of this additive on the structure and performance of membranes in the treatment of mentioned wastewater has been investigated. The results indicate that by increasing additive concentration, the porosity, thickness and flux are first increased and then decreased. Also this trend for the performance of membrane in pollution indices removal from the wastewater is reverse.

Cheese ripening is one of the most impotant stages during cheese production. After milk coagulation, in order to achieve the appropriate organoleptic properties, it should be exposure to the suitable environmental conditions. Proteolysis is the most substantial stage during cheese ripening. Several parameters are effected the proteolysis in cheese production process such as temperature, salt concentration, water activity and the amount of retentate coagulant enzymes in curd. The goal of present study was to investigate effect of temperature (4, 8, 12ºC) and salt concentration (8, 10, 12%) on kinetic of proteolysis during two monthes. Samples were exposed to physicochemical experiments each two weeks. In order to investigate kinetic reactions, the amounts of soluble nitrogen in pH= 4/6, non protein nitrogen, color intensity of α-casein and β-casein taint in Urea poly acryl-amide gel electrophoresis were measured. By increasing the temperature, degradiation of α-casein and β-casein and production of soluble nitrogen in pH= 4/6, and non protein nitrogen were intensified. Results are also showed that, rising the temperature in constant salt concentration, leads to increase the kinetic constant, whilst the calculated amounts of kinetic constant at 12ºC for all of parameters were the highest. By investigation of proteolysis kinetic in cheese and reciprocal effects of temperature and time, optimum ripening conditions were detrmined at 8 ºC and 10% salt concentration for 6 weeks to obtainig the product with suitable organoleptic properties and high quality.

Production of food products with low fat content is increasing because of high demand for low caloric foods and also nutritionally safer. Food coatings can be a good alternative to solve this problem and to reduce oil absorption during frying. Bamieh is one of the confectioneries produced by frying and during the frying process; the oil uptake is high. In this research, solution with 0 (control sample), 0.25, 0.5 and 0.75 % tragacanth gum were used as coating agent. Produced samples were stored at refrigerator for 30 days and effects of coating were evaluated on some qualitative properties at first day and each 10 day. Results showed that coating could reduce oil uptake from 18% for 0.25% coating to 68% for 0.75% coating. Also coating could reduce moisture content of the samples. Coating had no significant effect on peroxide value, but caused an increase in acidity in last days of storage, however, the increase in acidity was at acceptable level. Organoleptic evaluation showed that coating can increase acceptability of the Bamieh samples. According to the obtained results coating can be suggested as a suitable method to produce Bamieh with low oil content, higher acceptability and comparable stability with control sample.

Effect of heat treatment of soft wheat flour (with low and high gluten contents) was investigated on batter characteristics and cake quality. Physical properties of cake batter such as specific gravity and consistency, cake properties (volume, specific volume, apparent density, solid density, apparent porosity, moisture, symmetry and uniformity, color and firmness and the final score of sensory evaluation were evaluated. Results showed that increasing time and temperature of dry heat led to a decrease in specific gravity of cake batter, cake moisture content and an increase in the batter consistency, cake volume, specific volume and cake apparent porosity. However, moist heat (steaming) application on the flours decreased the latter parameter. Control and heat treated samples had similar solid densities. The best cake symmetry and uniformity were obtained for product obtained from heat treated flours at temperatures of 110 and 120 °C for 120 min. Higher crust color values were obtained for cakes prepared from steamed flours. Crumb color for all treatments was almost similar. At 7th and 14th day of evaluation, control cakes showed the firmest crumbs, while cakes prepared from steamed flours and heat treated flours (at temperatures of 110 °C and 120 °C for 120 min) showed the softest crumbs. Overall, sponge cakes prepared from dry heat treated flours presented better acceptability for the sensory judges. All the results in high and low gluten treatments had similar trends.

Effects of ferulic acid for preventing black spots forming or melanosis in whiteleg shrimps (Litopenaeus vannamei), and its replacement by synthetic compounds and determining the shelf life of shrimp in cold storage were evaluated. Four treatments were immersed shrimp in ferulic acid at two concentration of 2 % and 4% in sodium metabisulfite at a concentration of 3 % without ferulic acid. Peroxide value, thiobarbituric acid, free fatty acids and trimethylamine factors showed significant differences in 4% and 2% ferulic acid and sodium metabisulfite treatments compared to without ferulic acid (P<0.05). However, pH, protease and TVB-N showed no significant differences in experimental samples compared samples including of sodium metabisulfite and without ferulic acid (P>0.05). Sensory factors including color of 4% and 2% ferulic acid treatment showed significant difference compared to without antioxidant treatment (P<0.05). Sensory quality showed no significant difference in 4% ferulic acid treatment compared to sodium metabisulfite treatment (P>0.05). Color factor showed significant difference in 4% and 2% ferulic acid and sodium metabisulfite treatments compared to without ferulic acid control samples (P<0.05). Despite 4% ferulic acid and sodium metabisulfite treatments, black spot was formed in 2% ferulic acid treatments during 3 months storage. It was formed in without ferulic acid treatment in less than a month. According to the results, ferulic acid at a concentration of 4 % could be a proper substitute for sodium metabisulfite for preventing black spots forming in whiteleg shrimp during 6 months storage.