Comparative Influence of Dehulling on the Composition, Antioxidative and Functional Properties of Sorrel (<i>Hibiscus sabdariffa</i> L.) Seed

Abstract

Although animal proteins provide indispensable amino acids that the body requires for normal growth, maintenance and function, their expensiveness makes them unaffordable especially for most families in the developing countries. This has given impetus to extensive research into under-utilized protein-rich oilseeds such as sorrel as possible alternate sources of good quality protein for tackling the challenge of protein-energy malnutrition which is fast becoming a global challenge. Sorrel seed may hold great potentials as a source of good quality protein, however the presence of hard seed coat, bitter after-taste and associated antinutritional factors have limited its use as protein supplement for humans and food ingredient. This study therefore compared the effect of dehulling sorrel seed to boiling, germination and roasting. This was with the aim of enhancing its utilization as protein source for human nutrition and functional ingredient in food product development. Flours obtained were analyzed for their proximate, mineral, antinutrient, amino and fatty acids composition; in vitro starch and protein digestibility, and functional and antioxidative properties. Protein content (ranged from 24.93%-32.91%) significantly increased due to processing; dehulling alone accounted for a percentage increase of 32.01%. Similarly, dehulling increased all essential amino acids (except isoleucine and valine) at percentage which ranged from 3.63%-61.17% whereas other processing methods caused significant reductions. Lysine, leucine, valine, arginine and phenylalanine were the most abundant essential amino acids, while methionine and cystine were the first and second limiting amino acids. Palmitic, linoleic, oleic and stearic acids were the most abundant fatty acids. Mineral composition was K > Ca > Mg > Na > Fe > Zn > Mn. Dehulled seed flour had highest in vitro protein digestibility

Determining the influence of fava bean pre-processing on extractability and functional quality of protein isolates

“…This trend could be linked to their protein contents ( Table 1 ), where a higher level of protein allows greater entrapment of oil molecules. Similar trends were found in OAC of sorrel seed ( Ayo-Omogie & Osanbikan, 2019 ) and boiled Mucuna bean ( Mang et al, 2015 ) where dehulling increased the protein contents in the seed flours. The value obtained for OAC of FP-D is consistent with the value previously reported by Eckert et al (2019) , but higher than those reported by other studies ( Keivaninahr et al, 2021 , De Paiva Gouvêa et al, 2023 , Martinez et al, 2016 ).…”

Effect of dehulling, roasting, and cooking on the nutritional composition of Himalayan barnyard millet (Echinochloa frumentacea)

“…The increase in the protein value of the processed fractions may be due to the breakdown of crude protein into amino acids during processing. It has been reported earlier that when food is subjected to roasting, the activity of proteolytic enzymes is increased, which hydrolyzes inherent proteins to their constituent amino acids and peptides, hence improving the availability of nutrients 15,31 . Similarly, a significant increase in protein content was observed after dehulling, which might be due to the removal of polysaccharides (cellulose, pectin) and leads to a reduction of tannin and phytate, which bind protein and the enzyme required for protein digestion, thus further result in higher protein digestibility 32 .…”

“…Protein content was estimated using a CHNS analyzer (Vario EL, Elementar). Carbohydrate was calculated by difference method, 15 that is Total free amino acid was determined following Sadasivam and Manickam (1996) 16 . A total of 500 mg of the dried sample were extracted in 10 mL of 80% ethanol and centrifuged.…”

“…14 Protein content was estimated using a CHNS analyzer (Vario EL, Elementar). Carbohydrate was calculated by difference method, 15 that is…”

“…It has been reported earlier that when food is subjected to roasting, the activity of proteolytic enzymes is increased, which hydrolyzes inherent proteins to their constituent amino acids and peptides, hence improving the availability of nutrients. 15,31 Similarly, a significant increase in protein content was observed after dehulling, which might be due to the removal of polysaccharides (cellulose, pectin) and leads to a reduction of tannin and phytate, which bind protein and the enzyme required for protein digestion, thus further result in higher protein digestibility. 32 The protein results were quite similar to the earlier reports presented by Saleh et al, that is, 11% 33 and Ugare et al, that is, 10.5% 29 for barnyard millet samples.…”