Physicochemical, crystalline characterization and digestibility of wheat starch under superheated steam treatment.

This paper explored the impact of superheated steam (SS) treatment on the physicochemical, crystalline characteristics and in vitro digestibility of wheat starch. Upon SS treatment, treated samples showed lower swelling power, solubility, and viscosities, but had higher gelatinization temperature, which might be due to the partial gelatinization of starch granules. This agreed with micromorphology characterization, indicating the degradation of Maltese cross. In addition, SS treatment decreased the long-range crystalline and short-range order of starch, compared to native starch sample. This change of physicochemical and structural properties was responsible for the decrease of starch hydrolysis rate. Meanwhile, SS treatment obviously increased the slowly digestible starch (SDS) and resistant starch (RS) content from 10.6% to 7.9% (native starch) to 17.2% and 13.6% (150 °C, 1 min), respectively. This knowledge indicates that superheat steam technology possibly is a promising strategy in starch modification. [Display omitted] • Superheated steam (SS) treatment induced partial gelatinization of wheat starch. • SS treatment destroyed the long-range crystalline structure of wheat starch. • SS treatment increased resistant starch contents of wheat starch. [ABSTRACT FROM AUTHOR]