Changes in the structural and physicochemical characterization of pea starch modified by Bacillus-produced α-amylase

In this study, changes in structural and physicochemical properties of pea starch treated with Bacillus-produced a-amylase were determined. The results showed that enzymatically modified pea starch had lower amylose content and granule size but higher branching degree and relative crystallinity. After enzyme hydrolysis, the distribution of A and B1 chains slightly decreased, while the distribution of B2 and B3 chains increased lightly. Enzymatic hydrolysis preferentially occurred in the amorphous region and cannot change the crystalline structure of pea starch. Moreover, pea starch showed lower light transmittance, peak viscosity, breakdown viscosity, pasting temperature, shear viscosity, storage modulus and loss modulus, while the oil adsorption ca-pacity and gelatinization enthalpy significantly increased with increasing a-amylase hydrolysis time. Correlation analysis indicated that a-amylase hydrolysis had different effects on different pea varieties. This research could provide ideas for exploring new applications for enzymatically modified pea starch in food industry. Industrial relevance: This study found that Bacillus-produced a-amylase significantly changed the amylose con-tent, granule size and viscosity of pea starch, which was helpful to further investigate the modified starch. This technology is expected to widen the applications of pea starch modified by Bacillus-produced a-amylase in food industry, for example as thickener, stabilizer and beverage, to improve the texture, stability and shelf-life of various food products.