Effect of Enzymatic Extraction Treatment on Physicochemical Properties, Microstructure and Nutrient Composition of Tartary Buckwheat Bran: A New Source of Antioxidant Dietary Fiber

Abstract

The effect of enzymatic treatment with amylase and cellulase on Tartary Buckwheat (F. tataricum Gaertn) bran dietary fiber was evaluated by studying its chemical composition, physicochemical property and microstructure. Tartary buckwheat bran flour, obtained from residues of tartary buckwheat processing exhibited high contents of dietary fiber (44.2±0.3%), starch (31.94±0.27%), lipid (5.18±0.14%) and total ash (2.91±0.04%), and a low level of crude protein (3.12±0.11%). The contents of hemicellulose, cellulose and klason lignin were 23.80±0.21%, 17.48±0.25% and 4.06±0.21%, respectively. Total polyphenols and total flavonoids contents were 13.32mg GAE/g and 37.43mg RE/g, respectively. The water holding capacity (WHC) and swelling capacity (SC) were 2.22±0.07 g/g and 2.33±0.10 mL/g. After the extraction process with amylase, the dietary fiber, total polyphenols, total flavonoids contents of crude enzymatic extract were increased to 83.5±0.27%, 27.61 mg GAE/g, 52.14 mg RE/g, respectively. Its WHC and SC also grew up to 2.38±0.12 g/g and 4.67±0.09 mL/g, while the starch content was decreased significantly. The crude enzymatic extract from tartary buckwheat bran was modified by cellulase. After the modification treatment, the increasing proportion of soluble dietary fiber (SDF) against total dietary fiber (TDF) was detected, and its WHC and SC also grew up to 2.58±0.11 g/g and 5.13±0.12 mL/g respectively. By Small angle X-ray scattering (SAXS) analysis, it was also learned that the size of DF particles were decreased, which had a positive correlation with WHC and SC. The SEM photos showed that the modification processing increased the surface area of DF.

Modification of barley dietary fiber through thermal treatments

“…Among all treatments, the highest results were shown by cooking without soaking. Therefore, it was concluded that thermal processes can also change the ratio of soluble and insoluble fibers and physicochemical properties of dietary fiber (Zhou et al, ). These modify the composition and availability of nutrients.…”

“…For the purpose, thermal processes are considered as most important approach for the modification of soluble and insoluble fibers ratio and physicochemical properties of dietary fiber (Zhou, Qian, Zhou, & Zhang, ). Different methods are used for thermal modification such as sterilization, sun drying, steam processing, boiling, frying mainly deep fat frying, microwave drying, vacuum‐belt drying, roasting, and pressure cooking.…”

Effect of food processing on the physicochemical properties of dietary fibre.

“…Zhou et al (2012) reported that the water-holding capacity and swelling capacity of Tartary buckwheat (Fagopyrum tataricum Gaertn.) bran dietary fi ber were improved after enzymatic treatment, due to the increase in SDF/IDF and the decreased size of dietary fi ber particles.…”

Alterations in physicochemical and functional properties of buckwheat straw insoluble dietary fiber by alkaline hydrogen peroxide treatment

“…3(a) shows that the WHC of O-IDF and M-IDF was 7.10 g/g and 16.15 g/g, respectively. Both O-IDF and M-IDF also exhibited higher WHC values than the wheat IDF reference ( p < 0.05) and agricultural by-products from other fibers, e.g., 2.58 g/g from tartary buckwheat bran fiber (Zhou, Qian, Zhou, & Zhang, 2011), 3.6 g/g from rice bran DF (Wen et al, 2017), 6.1 g/g from wheat bran, 2.32 g/g from maize hulls, 2.48 g/g from wheat hulls and 4.9 g/g from soybean fiber (Alfredo, Gabriel, Luis, & David, 2009). The increase in the WHC of M-IDF according to the increase in the hydrogen peroxide process might be mainly attributable to the destruction of lignocellulose biomass structure.…”