DIGESTION OF COOKED STARCHES FROM DIFFERENT FOOD SOURCES BY PORCINE ALPHA-AMYLASE

The rate, limit and products of porcine α-amylase (EC.3.2.1.1) hydrolysis of cooked starches differ with starch source. The major controlling factors appear to be the amylose:amylopectin ratio and the gel age. The limit of hydrolysis of freshly prepared gels after 4 h treatment ranged from 70·5% for wrinkled pea (Pisum sativum) Cv. Scout to 92·2% for potato (Solanum tuberosum) starches. Ageing the gels before enzyme treatment reduced the limit of hydrolysis of the legume starches but not the cereal starches. The rate of hydrolysis of the α-amylase-susceptible fraction of the starches was unaffected. The maltose:maltotriose ratio in the hydrolysis products for the cereals was 1:0·90 whereas that for the legumes ranged from 1:0·84 to 1:0·60. The differing ratios appear to be related to the amylose:amylopectin ratio. © 1990.