Novel development and characterisation of dietary fibre from yellow soybean hulls

Dietary fibres (DFs) from yellow soybean hulls (Glycine max) were developed by mimicking pH in the human digestive system. Using both traditional AOAC991.43 and newly developed AOAC2011.25 methods, DFs were quantified, and their physicochemical properties were characterised by determining colour, particle size, water absorption and solubility capacity. Viscoelastic properties of the fibres with whole wheat flours were evaluated using dynamic rheological measurements. The results showed that colour of lightness (L value) was significantly improved (p<0.05). The levels of soluble, insoluble, and total dietary fibres determined by 2011.25 were 2.6±0.7%, 85.9±0.4%, and 88.5±0.8% (as is), respectively. There was an approximately 50% increase of total dietary fibre in the treatment, which reached 98.6±0.8% (dry basis). The results clearly indicated that acid-base hydrolysis and autoclaving processes in yellow soybean hulls could significantly boost total dietary fibre content, which has potential application in snacks.