Physicochemical and functional properties of protein extracts from Torreya grandis seeds

Proteins extracted from Torreya grandis seeds were investigated for their physicochemical and functional properties. The results showed protein extracts from two cultivars of T. grandis, Shengzhou I (SZPI) and Dazinaiyou (DNPI), had similar protein contents and appropriate amino acid balances with about 41% of the essential amino acid. The molecular weights of seed protein fractions were mostly about 31-37kDa and 20-21kDa. SZPI and DNPI had similar denaturation temperature of around 93.7°C while free sulfhydryl group and disulfide bond contents were found to differ slightly. The surface hydrophobicity of DNPI was 982, significantly (p<0.05) greater than that of SZPI (649). Both proteins exhibited high solubilities and favourable emulsifying abilities, foaming and fat absorption capacities, although their in-vitro digestibilities were rather low. Therefore, T. grandis seed proteins have potential as valuable nutrition sources and functional ingredients in food industry.