Extraction, characterization, nutritional and functional properties of Roselle (Hibiscus sabdariffa Linn) seed proteins

Physicochemical, nutritional and functional properties of protein fractions and protein isolate (RSPI) from Roselle seed were investigated. The protein content was 91.50, 93.77, 81.55, 71.30 and 40.83% for RSPI, globulin, albumin, glutelin and prolamin, respectively. The functional properties were variable among samples. Glutelin possessed the highest water holding capacity and albumin the lowest. The oil holding capacity ranged from 3.47 to 7.23 mL/g and the emulsifying capacity from 95 to 18 mL/g. Glutelin had the higher foam capacity, while RSPI showed the more stable foam. The molecular weight of all samples ranged from 55,000 Da to below 14,300 Da. All the estimated nutritional parameters based on amino acids composition suggested that Roselle protein fractions and its isolates have good nutritional quality and could be a good source of protein fortification for a variety of food products for protein deficient consumers as well as a potential food ingredient.