Optimization of ultrasonic‐assisted extraction of insoluble dietary fiber from wheat bran and its characterization

Ultrasonic-assisted extraction technique by means of response surface methodology was used to study optimized conditions for extraction of insoluble dietary fiber (IDF) from wheat bran varieties, namely Zincol-2016 (ZL), Borlaug-2016 (BG), NARC (NC), and Pakistan-2013 (PN). Optimized parameters for time, temperature, and amplitude ranged from 10 to 11 min for 30–40°C, and 64%–65% for all varieties with extracted IDF (39%–41%). FTIR spectra confirmed the presence of IDF in extracted material. DSC showed endothermic behavior near 100°C during the melting process. TGA showed stability at 99°C and complete degradation at 372°C. Chemical characterization of IDF extract showed a reduction in protein and fat, thus improving purity and IDF content. Tested technique also improved functional properties like cation exchange capacity (meq/kg) 16.30–17.66, emulsifying capacity (%) 32.1–32.98, and swelling capacity (ml/g) 4.43–5.98 to a high level. Briefly, under-tested extraction parameters, the IDF has improved chemical and functional characteristics. Practical applications The study concludes that ultrasonic extraction, under-explored moderate, and optimized conditions will prove an efficient extraction technique yielding considerable quantity and quality of IDF from wheat bran. The above results show the possibility for the application of all tested samples of IDFs in the food industry, especially to expand the thermal stability of food for various purposes. The ultrasonically extracted IDFs have better structural integrity and functional characteristics which play an important part in preparation and quality maintenance of food products, especially cereal food products.