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The effect of varying autoclaving conditions and added sodium hydroxide on amino acid content and nitrogen characteristics of feather meal
Author(s) -
Papadopoulos Manthos C.,
ElBoushy Adel R.,
Roodbeen Albertus E.
Publication year - 1985
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740361204
Subject(s) - food science , chemistry , methionine , sodium hydroxide , cystine , nitrogen , amino acid , solubility , essential amino acid , meal , lysine , feather meal , sodium , biochemistry , fish meal , organic chemistry , biology , cysteine , enzyme , fishery , fish <actinopterygii>
The effects upon amino acid content and nitrogen characteristics of feather meal subjected to varying lengths of processing time (30 to 70 min) moisture content (50 to 70%) and added NaOH (0.2 to 0.6%) were studied by multiple regression techniques. All test products were autoclaved at constant pressure of 345 kPa. The results obtained showed that prolonged processing periods and increased concentrations of NaOH had a substantial effect on the amino acid contents and in particular on the essential ones. There was a marked degradation of cystine, and smaller losses of lysine and methionine. Most of the amino acid contents were lower in the meals with a higher moisture content. In vitro protein digestibility and solubility in alkali and acid, were generally increased by prolonged processing conditions. It was concluded that the inverse relationship between amino acid content and nitrogen characteristics should be taken into account for feather meal evaluation. Higher values for in vitro protein digestibility and solubility were considered to be favourable unless other structural modifications to the protein affect its nutritional value.