Effects of the beta-glucan, curdlan, on the fermentation performance, microstructure, rheological and textural properties of set yogurt

摘要

Phase separation becomes a hindrance to application of beta-glucans in set yogurt production. In this study the effect of a gel-forming beta-glucan, curdlan, on set yogurt fortification was investigated in the level of 0.1%, 0.2%, and 0.5% (w/w). The cell viability in curdlan-fortified yogurt ranged from 88.3 +/- 7.3% to 93.1 +/- 3.8%, suggesting well compatibility of curdlan with the yogurt starter cells. Curdlan increased the water holding capacity of yogurt and reduced the release of fat granules. Moreover, curdlan improved the resistance of yogurt against high shear stress (5-50 s(-1)) and oscillation deformation (strain < 50%). Rheological results combining with the SEM images implied that the fortification mechanism of curdlan on set yogurt was mainly attributed to the physical support of an additional gel structure embedded in the network of casein coagula. The texture profile analysis proved that the hardness at the first compression was significantly enhanced after curdlan addition regardless of the dose while the cohesiveness and gumminess increased at 0.5% curdlan level. Besides, application of curdlan in yogurt didn't significantly affect the sensory acceptance according to the scores obtained from 81 participants. In conclusion, curdlan is a competent substitute for application in set yogurt production in lieu of other beta-glucans.