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Whole stillage--a co-product of grain-based ethanol--is used as an animal feed in the form of dried distiller's grain with solubles (DDGS). Since animals cannot synthesize carotenoids and animal feed is generally poor in carotenoids, about 30-120 ppm of total carotenoids are added to animal feed to improve animal health, enhance meat color and quality, and increase vitamin A levels in milk and meat. The main objective of this study was to produce carotenoid (astaxanthin and β-carotene)-enriched DDGS by submerged fermentation of whole stillage. Mono- and mixed cultures of red yeasts, Phaffia rhodozyma (ATCC 24202) and Sporobolomyces roseus (ATCC 28988), were used to produce astaxanthin and β-carotene. Media optimization was carried out in shake flasks using response surface methodology (RSM). Macro ingredients, namely whole stillage, corn steep liquor and glycerol, were fitted to a second-degree polynomial in RSM. Under optimized conditions, astaxanthin and β-carotene yields in mixed culture and P. rhodozyma monoculture were 5 and 278, 97, and 275 μg/g, respectively, while S. roseus produced 278 μg/g of β-carotene. Since the carotenoid yields are almost twice the quantity used in animal feed, the carotenoid-enriched DDGS has potential application as "value-added animal feed or feed blends."

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Microbial cellulases and pectinases from various sources exhibited different degrees of activity when employed to reduce the viscosity of mango pulp. Ultrazym 100 rapidly reduced mango pulp viscosity up to 82% (unfiltered) and yielded pulp juices which could be filtered or centrifuged easily. Enzymatic liquefaction of mango pulp was influenced by temperature, enzyme concentration, and time of reaction.

No abstract