Properties of Potato Resistant Starch and Its Effect on the Growth of Probiotics

This study uses potato starch as raw material to prepare potato resistant starch (PRS3) using a pressure heating dual enzyme method and purifies it. The physicochemical indicators such as swelling power, solubility, freeze-thaw stability, transparency, oil absorption, milk absorption, and water holding capacity of purified PRS3 are measured. The growth and proliferation of probiotics (Lactobacillus acidophilus, Lactobacillus bulgaricus, Bifidobacterium, Streptococcus thermophilus, and Lactobacillus paracasei) under different carbon source concentrations of PRS3 medium, soluble starch medium, and glucose medium, as well as their effects on the growth process are studied. The authors also discusses the effects of glucose medium and PRS3 medium on salt and acid tolerance of probiotics. The results show that the freeze-thaw stability, solubility, and milk absorption capacity of PRS3 are stronger than those of original potato starch, but its oil absorption, water holding capacity, swelling capacity, and transparency are weaker than those of original potato starch. When the carbon source concentration is 2.0%, the proliferative effect of PRS3 on five bacteria is in descending order: Lactobacillus acidophilus, Lactobacillus bulgaricus, Bifidobacterium, Streptococcus thermophilus, and Lactobacillus paracasei. The ability of PRS3 medium to promote the proliferation of probiotics is stronger than that of glucose medium and soluble starch medium. It has a protective effect on probiotics in low pH environments and can improve their resistance to bile salts.