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THE INFLUENCE of HEAT TREATMENT ON the ACTIVITY of LIPO‐AND HYDROPHILIC COMPONENTS of OAT GRAIN
Author(s) -
ZADERNOWSKL RYSZARD,
NOWAKPOLAKOWSKA HALINA,
RASHED ABDUL ALEEM
Publication year - 1999
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.1999.tb00378.x
Subject(s) - chemistry , antioxidant , polyphenol , food science , flavonols , ascorbic acid , organic chemistry , phenols , roasting , lipid oxidation , lipase , phenol , phenolic acid , enzyme
Lipids in oat grains are protected against oxidation by various chemical compounds with antioxidant properties. Biologically active compounds such as tocopherols, L‐ascorbic acid, thiol, phenolic amino acids and phenol comnpounds feature such properties. Phenolic compounds inhibit lipase activity, protect lipids against oxidation and, as a consequence, protect plant cells against the destructive activity of free radicals. the disadvantage of natural antioxidants is their low resistance to high temperatures since heating over 80C destroys their antioxidant properties. Operation such as drying, blanching, roasting or extrusion destroy the protective system of plant lipids. The paper is an attempt to explain to what degree extrusion conditions influence activity of natural antioxidants. Oat flour possessing the largest amnount of lipids and biologicaly active compounds compared to other cereal flour was used in the model system. It has been found that oat phenolic compounds are a mixture of free phenolic acids, esters and phenolic acid glycosides as well as flavonols and polyphenols. It has been established that alcoholic extracts produced from oat groat and flour had strong antioxidant properties, whereas the extracts from extruded substances did not reveal such properties. During extrusion, about 50% degradation of phenolic compounds was observed. Phenolic compounds were the main group of organic compounds enabling enzyme activity and playing an antioxidant role.