Effect of soaking time in sodium metabisulfite solution on the physicochemical and functional properties of durian seed flour

Abstract

With regard to its high carbohydrate and gum contents, durian seed flour has been used as a substitute to wheat flour in butter cake and cookies manufactures. Unfortunately, processing of fruit seeds into flour may be hampered by discoloration, which may affect the nutrition and sensory quality of the food products. The objective of this study is to investigate the effect of soaking time on the physicochemical and functional properties of durian seed flour. Durian seed chips were soaked in 0.6% w/v sodium metabisulfite solution as anti-browning agent at 30°C for desired periods (40, 60, 80, 100, 120 minutes), followed by drying at 50°C for 17 hours, milling and sieving to obtain flour. The flour was analyzed for its moisture, ash, protein, fat and carbohydrate contents, sulfite residue, yield, gelatinization temperature, and water and oil absorption capacities (WAC and OAC). The results showed that longer soaking time reduced the moisture and ash content of durian seed flour, but increased most of the other studied parameters. The WAC, OAC and fat content were less affected by soaking time. It can be concluded that soaking of durian seed chips in sodium metabisulfite solution can improve the nutrition and functional properties of flour. Based on the residual sulfite content, durian seed flour obtained in this work is safe for consumption.