Content of nitrogen compounds in raw and preserved seeds of grass pea (Lathyrus sativus L.)

Abstract

The content of nitrogen compounds in seeds of two grass pea cultivars harvested at a 33% level of dry matter content, and also in their cooked frozen and canned products was determined. Raw seeds of the analysed cultivars – Derek and Krab – contained 4.8% and 4.6% of total nitrogen in dry weight respectively, the protein nitrogen constituting 71% and 63% of the above values. The level of amino acids was also similar in the two cultivars, particularly if calculated per 16 g of nitrogen. Cooked frozen and canned products were characterized by a smaller content of total nitrogen than in the raw material. The content of protein nitrogen on a dry matter basis was 6–7% less in cooked frozen seeds and 11–12% greater in canned seeds than in raw seeds. The content of amino acids expressed per 16 g of nitrogen in the final products varied from 87% to 112% compared to the raw material, hence the index of the limiting amino acid and the integrated index of essential amino acids for these products were similar to those found in protein of the raw material. In all the analysed samples, the limiting amino acids were methionine and cysteine. The raw and preserved seeds of grass pea contained negligible amounts of nitrates and nitrites.