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Passion fruit is now grown worldwide as a delicious edible fruit for the food industry. In order to analyse the influence of the addition of passion fruit pulp on the quality of goats' milk yogurt, the physico-chemical, sensory and antioxidant properties of the yogurt during refrigerated storage were investigated by measuring pH value, titratable acidity, susceptibility to syneresis, viscosity, hardness and antioxidant capacity. The results showed that supplementation with passion fruit pulp improved some of the physico-chemical and sensory characteristics. During 2 weeks of storage, viscosity and susceptibility to syneresis continuously increased and hardness was higher compared to that of the control group. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and OH radical-scavenging rate as well as Fe3+ reducing capacity increased, goats' milk yogurt with 20 g·kg-1 passion fruit pulp showed a higher antioxidant activity. However, pH of the yogurt decreased. Overall, the results support the hypothesis that passion fruit pulp is a promising option as a dietary supplement to produce novel dairy products that have high nutritional value and high antioxidant activity. [ABSTRACT FROM AUTHOR]

novel high-throughput method was established for rapid screening of large numbers of Aspergillus niger mutants with high transglucosylation activity by exploiting that yeast can hardly hydrolyze isomaltooligosaccharides (IMO). Supernatants of A. niger fermentation were incubated with Saccharomyces cerevisiae to remove glucose and maltose, and the remaining non-reducing sugars, which is positively correlated with the amount of IMO, the products of transglucosylation reaction, were used as indicator of transglucosidase activity of A. niger and examined by dinitrosalicylic acid assay. Using this method, 15 stains that could convert liquefied cassava starch to IMO more efficiently were selected from 8721 A. niger mutants. Among them, mutant C-6181 strain had transglycosidase activity of 4.61 U/ml (increased by 122% compared to its parental strain) and IMO yield of 83.7%. Taking together, the method is easy, simple, efficient and cheap, and has great application potential in selection of transglucosidase-producing strains used in industrial IMO fermentation. [ABSTRACT FROM AUTHOR]