Thermal behaviour of wheat starch and flour at different water levels: Effect of pectins, modified celluloses and NaCl

Abstract

Rapid viscoanalyser (RVA) and differential scanning calorimetry (DSC) can beappliedto studythermal transitions in starch based systems at different water levels. The effect of different hydrocolloids on wheat starch thermal transitions in the presence and absence of NaCl (2%) was evaluated in flour– hydrocolloid suspensions, starch–hydrocolloid mixtures and dough. These hydrocolloids include microcrystalline cellulose (MCC), carboxymethyl cellulose (CMC), two types of hydroxypropylmethylcellulose (HPMC F 4M and F50), a lowmethoxyl pectin (LMP) and a highmethoxyl pectin (HMP). The suspensions were submitted to a heating/cooling cycle in an RVA and a DSCwas used to evaluate gelatinization and ALC transition in dough and mixtures. All of the suspensions containing NaCl exhibited higher hot paste stability. Furthermore, CMC and pectins showed an inhibitory effect on amylose retrogradation. Results also showed that starch thermal transitions in limited and excess water can be highly affected by hydrocolloids, particularly when NaCl is present.