Effects of highland barley protein and β‐glucan addition on the flour structure, bread quality and starch digestibility of whole wheat bread

Abstract

SummaryWhole wheat bread is rich in nutrition, but its starch digestibility is unsatisfactory. Thus, how to reduce its digestibility has attracted much attention. This study investigated the effects of highland barley protein and β‐glucan on the pasting properties, and thermal properties of whole wheat flour to reveal the mechanism of highland barley protein and β‐glucan regulating the in vitro digestibility. The digestibility results showed that β‐glucan and protein could slow down starch digestion to some degree. The cross‐section structure determination results indicated that β‐glucan and protein decreased the porosity. The differential scanning calorimetry and thermogravimetric analysis results showed that β‐glucan and protein increased the onset of pasting, decreased the peak temperature and enthalpy of pasting and decreased the thermal stability. The Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy results revealed a blue‐shift in the ‐OH position of the bread added with protein and β‐glucan (from 995.59 to 996.07 cm−1), indicating that the hydrogen bonding might form intramolecularly. In this study, the addition of highland barley protein and β‐glucan was proved to be helpful in decreasing the in vitro digestibility and showed modification in the texture quality of bread, which might be suitable for diabetic patients.

Effects of dietary fibres, polyphenols and proteins on the estimated glycaemic index, physicochemical, textural and microstructural properties of steamed bread

“…Pan et al (2021) found that the hardness and springiness of catechinadded steamed bread were reduced and the chewiness increased. Zhang et al (2023) also showed that the addition of barley protein increased the hardness and chewiness and decreased the cohesiveness of bread. Dietary fibre thickened the walls around the air chambers in the bread crumbs, which strengthened the gluten backbone thereof.…”

“…protein-starch gel formed by the protein and starch chains could give the sample a higher hardness value and the addition of protein led to the disruption of the gluten structure and the formation of a denser pore structure (Ni et al, 2020;Pan et al, 2021;Meng et al, 2022;Zhang et al, 2023).…”