EXTRACTABILITY OF COCONUT PROTEINS

Abstract

SUMMARY —Studies were made on nitrogen (protein) solubility of coconut meal in aqueous media over a range of pH's. The point of minimum solubility was found at pH 3.9 and nitrogen solubility increased toward the acidic and basic sides. Coconut proteins displayed a markedly different pH‐nitrogen solubility profile in salt solutions, showing minimal solubility at acidic pH's (pH 3), a sharp rise of solubility and a maximum at neutrality. Coconut meal prepared from fresh coconuts with and without testa removed, from parings and from a sample of sun‐dried copra showed comparable solubility characteristics. However, meal prepared from commercial desiccated coconut showed low solubility, even under acid and alkaline conditions (pH 2 and 10). The most efficient solvent‐to‐meal ratio was found at 20:1 (v:w) for a single extraction, and a two‐step 15:1 process for multiple extractions. Extractions using salt solutions show that the efficiency of extraction is greatly dependent upon pH; concentrations 0.25M effect maximum extraction. Osborne classification studies of coconut meal indicate that 90% of the proteins would be classified as albumins and globulins.