Properties of some citrus seeds. Part 2. Functional properties of seed flours

Abstract

Water and fat absorption, gelation, protein solubility, emulsification and foam capacities of flours from citron, orange and mandarin seeds were determined. The protein solubility of the flours was increased as sodium chloride concentration increased up to 0.8 M for citron, mandarin and mixture seed flours and 1 M for orange seed flour, then decreased at higher concentrations. The minimum solubility was sharp for mandarin and orange seed flours, while, it was broader for mixture and citron seed flours. The least concentration for forming gel was 6%, 6.5% and 7% for mandarin, orange and both citron and mixture seed samples, respectively. The flours of orange and mandarin seeds were the highest and lowest in water absorption capacity. Also, the highest value of fat absorption capacity was noticed for citron and lastly for mandarin on flour basis. The emulsification and foam capacity-pH patterns were similar to protein solubility-pH profiles for all citrus seed flours. Foam capacity of mandarin and mixture seed flour were lower than that of citron and orange seed flours. The emulsification and foam capacities patterns in sodium chloride solution showed an increase up to 0.6 M and then decreased in all citrus seed flours. Foam stability of citrus seed flours was increased with sodium chloride concentration up to about 0.6 M and then decreased. The foam stability of all citrus seed flours at pH 4.5 was very poor but at pH 2, it was comparable to that at pH 8.