Abstract
A study was conducted on the effects of several kinds of commercial processed foods, which were brown-colored due mainly to enzymatic or non-enzymatic browning, on the activity of α-amylase from human saliva. The investigated foods included 4 types of soy paste, 5 types of soy sauce, 5 types of sauce, 5 types of tea and 5 miscellaneous other products. Starch Azure, which is chemically modified and insoluble potato starch, was used as a probe substrate for digestion in the presence of food components. The enzymatic reaction medium was 0.1M NaCl-0.04M sodium/potassium phosphate buffer (pH 7.0) containing 1mM CaCl2. The reaction solution was incubated at 37°C. The blue pigment solubilized from the solid substrate into the supernatant on digestion by α-amylase was determined by differential spectrometry using its absorption at 595nm. Some foods below the concentration normally eaten were found to exert an adverse effect on the activity of α-amylase with the following relationship: log (A/100) =-α·F.F: conc. of food component, A: relative activity, α: coefficient corresponding to inhibitory efficiency. In this experiment, a correlation between inhibitory effect and coloredness of food components was not confirmed, and the involvement of complex factors in the inhibition was suggested.
