Preparation and properties of a white protein fraction in high yield from sugar beet (Beta vulgaris L) leaves
Abstract
Chlorophyll-free protein has been recovered at a yield in excess of 50 % from sugar beet (Beta vulgaris L) leaf juice after two successive pH treatments. This corresponds to about 60 kg of white protein per hectare. The main component of the final preparation is ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39). Compared with the unfractionated protein from leaf extracts, the white protein preparation has higher contents of tyrosine, threonine, glutamic acid and proline and lower ones of isoleucine, lysine (although still high: 76mg g−1) and glycine. The content of methionine is high (24mg g−1) probably as a result of the addition of sulphite during protein extraction. The white protein preparation has a low level of ether extractives (17mg g−1) and a moderate ash (52mg g−1) content. The white protein is rapidly degraded by pepsin, trypsin and pancreatic juice.
- Publication:
-
Journal of the Science of Food and Agriculture
- Pub Date:
- January 1988
- DOI:
- 10.1002/jsfa.2740440305
- Bibcode:
- 1988JSFA...44..237M