Changes in the level of vitamin C, beta-carotene, thiamine, and riboflavin during preservation of immature grass pea ( Lathyrus sativus L .) seeds

Abstract

The aim of the work was to evaluate the content of vitamin C, beta-carotene, thiamine, and riboflavin in raw and preserved physiologically immature grass pea seeds. The seeds of the cultivar Krab, differing in their morphology, phytometric traits, and specific gravity were divided into four stages of maturity, which corresponded to the following levels of their dry matter content: I – 25.9, II – 30.1, III – 36.4, and IV 40.6 g/100 g. The evaluation was conducted at the stage of the raw material, the material after blanching, frozen seeds after 6-month storage before and after cooking to the consumption consistency, and canned seeds 6 months after production. With the maturity degree of grass pea seeds the content of vitamin C was reduced by 19%, beta-carotene by 29%, riboflavin by 20%, while that of thiamine increased by 97%. The blanching of seeds led to a statistically significant decrease only in the content of vitamin C. Freezing and frozen storage did not significantly affect the level of the analysed components. The cooking of frozen seeds, the preservation of canned products, and their storage significantly reduced the content of all the analysed components in all the samples. No dependence was found between the magnitude of decreases in the investigated compounds and the degree of seed maturity. After cooking frozen seeds prepared from the raw material at the same maturity degree as the canned product contained 32%–51% more vitamin C, 0%–8% more beta-carotene, 40%–97% more thiamine, and 20%–25% more riboflavin, depending on the degree of seed maturity.