Functional and thermal properties of flour obtained from submerged fermentation of durian (Durio zibethinus Murr.) Seed chips using Lactobacillus plantarum

Durian (Durio zibethinus Murr.) is one of the most popular seasonal fruits in South East Asia, mainly Thailand, Indonesia, Malaysia and the Philippines. After consuming of the fruit pulp, the abundant durian seeds are usually disposed. However, they can be eaten after being boiled, roasted, baked, fried or cooked. Unfortunately, there is no sufficient information on the innovative utilizations of the durian seeds as raw materials in the preparation of modern foods. This study aims to characterize the functional and thermal properties of native and fermented durian seed flour obtained from submerged fermentation of durian seed chips using Lactobacillus plantarum, so that this information can be used as the basis in the development of functional foods. The effect of solid consistency (5 – 25% w/v), inoculum size (2.5 – 15% w/v) and time (0 – 40 h) on the swelling power, water solubility, water absorption capacity, oil absorption capacity, carbonyl and carboxyl content, degree of substitution and gelatinization temperature of the flour were investigated. Fermentation was found to alter all of the functional and thermal properties of durian seed flour. Although fermentation increased the gelatinization temperature and oil absorption capacity of durian seed flour, their value were still lower than that of wheat flour. Based on the carboxyl group content and degree of substitution, the fermented durian seed flour obtained from fermentation of durian seed chips at 15% w/v solid consistency and 5% v/v inoculums size for 24 h is safe for consumption. Fermented durian seed flour exhibits similar functional properties to that of wheat flour and offers its superiority and high potential applications in the food industry over wheat flour due to its high fiber content (8.50 ±0.26%), but low fat content (0.63 ±0.03%). However, rigorous research should be conducted to ensure the acceptability and practical implementation of fermented durian seed flour as raw material for the manufacture of bread, cookies, cake and noodle.