EFFECT OF STORAGE AND LIPID EXTRACTION ON PROPERTIES OF LEAF PROTEIN

At 4° and 28° extensive oxidation of leaf protein occurred, but there was little change in the digestibility of the protein, or in the N and P contents of the lipid. After heating at 60° the amount of extracted lipid decreased: a small decrease in digestibility was attributed to heat damage rather than oxidation of the lipid. Losses in digestibility after heatingat 100° wereattributable to two different reactions: (a)a lipid complexing reaction which depends on moisture content, but not on the presence of oxygen and (b) modification of the protein. The latter reaction occurred more slowly and depended mainly on the period of heating at 100°; it did not occur in completely dry protein, was not influenced by the presence of leaf lipid, and was not affected by lipid solvent extraction after heating. The possibility that lipid‐protein complexing during preparation of leaf protein causes losses in digestibility is discussed. Similarities between the behaviour of leaf proteins and fishmeal on storage and heating are also discussed. Copyright © 1969 John Wiley & Sons, Ltd