The gelation mechanism of mung bean starch as affected by edible alum

Abstract

Abstract To understand the gelation mechanism of mung bean starch (MBS) as affected by addition of edible alum, the physicochemical properties of MBS gels and their gelation process under 0–0.25 % of alum addition were studied. The results showed that alum incorporation enhanced the gel texture and starch-water interaction in a concentration-dependent manner. With increasing amount of alum addition, the pH value and ζ-potential of MBS decreased, while the swelling power, pasting viscosity, the leached amylose content, gelation temperature, short-range ordered structure and the crystallinity of MBS gels increased. It is believed that alum addition improved the texture of MBS gels by promoting amylose leaching, starch aggregation and recrystallization. The increase in starch-water interaction might be due to the destruction of MBS structure by polar ions and the formation of clathrates by leached amylose and Al3+ ions.