JWSS - Journal of Water and Soil Science

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Carotenoids are one of the most important and widely distributed pigments in nature and have essential biological functions in organisms. They also impart distinctive and attractive coloration to the breeding animals. Over the past two decades, application of microbial carotenoids has attracted the attention of researchers due to their natural and economic advantages. However, carotenoid producing yeasts with lactose assimilating capacity have rarely been studied and there are few references on the use of lactose as a carbon substrate, such as whey, for the biosynthesis of yeast carotenoids. In this study, a red carotenoid-producing yeast, Rhodotorula acheniorum, was isolated from the sap of birch trees at Masseh Chal in the Taleghan village. The yeast thus isolated was identified through microscopic, macroscopic and biochemical tests.

The yeast has both the abilities of lactose assimilation and carotenoid production. The optimal conditions of culture were determined and maximum biomass and carotenoid production were 9.9 g/lit, 290 µg/g, respectively. Chemical analyses of extracted carotenoids have shown that the major portion of the yeast consists of β-carotene, torulene and torularhodin. With regard to the fact that whey is one of the by-products of cheese industries and that its proper disposal has long been a major problem, the most desirable way of handling this waste is to utilize it as a substrate in the production of useful products such as carotenoids.

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Whey powder, due to its lactose and protein contents, can be used as an important flour improver to decrease the rate of staling. In the present investigation, whey powder was added at 5 levels (zero to 5%, W/W) to the flour of Sangak bread. Bread was baked according to the formula and procedure used by traditional Sangak bakeries. Bread samples were kept at room temperature or under refrigeration for 36 hours. They were then evaluated for staling by a taste panel. They were also subjected to proximate analysis. The dough was examined for farinographic, amylographic, extensographic and fermentographic properties. The data of staling tests including color, texture, flavor and also proximate analysis data were analyzed by ANOVA. Finally, differences among treatments were examined by Ducan’s multiple range procedure. The results indicated that the best treatment was the use of 3% whey powder, as far as staling and texture of bread are concerned. However, the best color of bread was achieved with 5% whey powder so was true of the protein, ash and fat contents. Viscosity, as tested by amylography, and also parameters of farinography reached their highest levels in the dough prepared from flour having 5% whey powder in the formula. The best extensibility was observed with the flours containing 4% whey powder and the highest dough energy was associated with the dough prepared from flour having 5% whey powder. As for the loaf volume, best results were obtained with the dough prepared from flour having 3% whey powder. Overall, it is concluded that the use of 3% whey powder is the best treatment with regard to the delay in the rate of staling, increase in loaf volume, and color appeal of Sangak bread, and rheological properties of the dough.

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This experiment was conducted to investigate the effect of whey via drinking water on broiler chicken performance. In a completely randomized design, whey at levels of zero, 10, 20, 40, 80, and 100% of drinking water was used for 47 days. 720 day-old broilers (Ross) were divided into 24 groups, 30 chicks per group and each experimental treatment was given to four replicates from 7-54 days of age. The whey was supplied freshly. The chicks had free access to feed and water during the experimental period. All chicks were fed with starter, grower, and finisher diets. Chicks in all pens were weighed and their feed consumption was calculated at 21, 42 and, 54 days of age. At the end of the experiment, two males and two females from each pen were selected, killed and their carcass, abdominal fat, pancreas, liver and ileum were weighed. Ileal contents of each pen were collected and pooled and kept at -20^oC for bacterial count. The litter moisture content of each pen was determined at days 21 and 42. Body weight, daily body weight gain, feed conversion, and litter moisture were significantly (P<0.01) affected by whey levels. These indices decreased as a result of consuming whey by more than 40% feed conversion, however, increased. Percentage of carcass decreased significantly (P<0.01) due to consumption of 80 and 100% whey. Percentages of abdominal fat, liver, and pancrease were not significantly affected by the amount of whey. Percentage of ileum increased and showed significant (P<0.05) difference with control group. The regression equations for body weight and daily body weight gain, feed conversion and litter moisture in all ages, were significant (P<0.05) and polynomial. This indicated that consumption of whey by more than 40% caused reduction in broiler performance. No significant differences were observed in ileal contents of Lactobacillus and Entrobacteria due to different levels of whey, but total bacteria in ileum contents increased significantly (P<0.01) as whey content in drinking water increased.

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A dairy chocolate-flavored beverage was prepared using 55 % whey permeate and 45% whole milk. The beverage was sweetened by 3% date extract and 3% sugar. The blend was mixed with 0.7% cacao powder, 0.2 % caraginan, 0.15% vanilla , 3% skim milk powder, and 3% pasteurized cream(30%fat). Control sample was prepared by 100% whole milk without skim milk powder and cream. Both samples were heated up to 50 ⁰C , blended by a mixer for 2 minutes, then pasteurized at 85⁰C for 30 seconds and immediately cooled down to room temperature. Stability, pH, protein, total solids, fat and acceptability of the beverage and control samples were then evaluated. The new beverage had high acceptability.

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This experiment was conducted in a completely randomized design with five treatments and four replications. There were 15 chicks in each replication during the first 30 days and 10 chicks from day 30 to the end of experiment. Diets were control (without probiotic and dry whey) and levels 500 and 750 gm/ton probiotic, and each level contained two diets with and without %2 dry whey. Daily weight gain, feed intake, feed conversion rate at the end of each experiment and carcass characteristics including weights of neck, Liver, wing, heart, and abdominal fat on the 49th day of experiment were measured. Chicks which received diets with 500 and 750 mg/ton probiotic +%2 dry whey were significantly heavier than other chicks (p<0/05) between 0-21 days. Feed intake significantly increased during 3 periods including 0-21, 21-42, and 42-49 days of experiment, when chicks used diets with dry whey, especially diets containing 750 gm/ton probiotic (P<0/05). Blood plasma cholesterol significantly decreased when chicks used diets with dry whey. Also an increase in white cells was observed in days 21 and 35. Treatments did not have any significant effect on feed conversion rate, mortality and carcass characteristics (P>0/05).