Nitrogen extractability of sesame (Sesamum indicum L.) seed and the preparation of two protein isolates
Abstract
Nitrogen extractability from sesame flour in water is greatest using a flour: solvent ratio of 1:40 and an extraction time of 15 min. At pH 4.0-6.5, <10% nitrogen is extracted, whilst >90% is extracted at pH 11.0. In the presence of NaCl (0.5-1.0M) nitrogen extractability is greatest at pH values > pH 4.0. The two sesame protein isolates produced were bland-tasting, light-coloured and contained approximately 95% protein. The alkali isolate (extracted in water at pH 10.0 and precipitated at pH 4.0) was readily solubilised and showed a good protein recovery (60%). The salt isolate (extracted in 1M NaCl at pH 6.0 and precipitated at pH 4.0) was less soluble and showed a lower protein recovery (50%). The sesame products were extracted sequentially using various solvents. Sesame flour proteins were mainly salt-soluble (67%), alkali isolate proteins mainly water-soluble (41%) and alkali-soluble (41%), and salt isolate proteins mainly alkali-soluble (35%). The amino acid composition of the sesame products is described. Oil-expelled cake showed poor nitrogen extractability (53% at pH 11.0 in water) and was, therefore, a poor source for protein isolate production.
- Publication:
-
Journal of the Science of Food and Agriculture
- Pub Date:
- June 1981
- DOI:
- 10.1002/jsfa.2740320607
- Bibcode:
- 1981JSFA...32..565R