Märkäkuumennus tärkkelyksen entsymaattisen hajoamisen tehostajana I. Tärkkelyspreparaateilla ja jauhetulla viljalla tehdyt kokeet

Authors

• Maija-Liisa Salo Helsingin yliopiston kotieläintieteen laitos
• Irmeli Korhonen Helsingin yliopiston kotieläintieteen laitos
• Ulla-Riitta Lehtonen Helsingin yliopiston kotieläintieteen laitos

DOI: https://doi.org/10.23986/afsci.71766

Abstract

Factors affecting the enzymatic hydrolysis of starch have been investigated, the main object being the hydro-thermal processing of cereal meals. The following results were noted: – The amyloglucosidase method is well suited to the evaluation of the cooking-degree of meals and the mechanical damage of starch granules. The optical birefringence method and the Congo-red staining method can be applied in rough estimation alone. – Without gelatinization, amyloglucosidase is able to hydrolyse only 11—13 % of pure cereal starch, and even less of pea and potato starch. Complete hydrolysis is effected by gelatinization. The fermentability of raw starch is somewhat increased also by mechanical damage of the starch granules. A pepsin-hydrochloric treatment, simulating the digestive stomach-conditions, does not increase the fermentability of wheat and potato starch. – Addition of 20 % of water and heating at a temperature of 120°C in an autoclave causes almost complete susceptibility of the starch to enzyme attack in wheat, barley and oat meal, although the small amount of water does not induce perceptible swelling of the starch granules. In general the conditions of the hydro-thermal processing should be so adjusted that the entire cereal lot attains the gelatinization temperature, and that its moisture content remains stable.