This study investigated the effects of resistant starch (RS) 2 (a high-amylose corn starch) and RS3 (physically modified corn starch) on yogurt quality. Yogurt containing Bifidobacterium BB-12 was treated with RS2 or RS3 to a final concentration of 1.5%, with the control group receiving 1.5% (wt/wt) of sucrose. Multispeckle diffusing wave spectroscopy and scanning electron microscopy were used to investigate the effect of the resistant starches on the gelation process and microstructure of yogurt. The quality of the yogurt treatments was evaluated using viable counts of Bifidobacterium BB-12 and all viable cells, titratable acidity, amount of whey separation, and viscosity during storage. The resistant starches affected the progress of gelation and microstructure and decreased the decline of viable counts of Lactobacillus. Notably, RS3 effectively protected the Bifidobacterium BB-12, increased the viscosity, and decreased titratable acidity. Our results suggested that RS could improve the quality of yogurt and have a more probiotic effect. Further studies could lead to optimization in yogurt processing by mixing these 2 types of RS to determine their best usage and explore their interactions with proteins.
Keywords: quality; resistant starch; yogurt.
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