Digestibility and Pasting Properties of Rice Starch Heat-Moisture Treated at the Melting Temperature (Tm )

Abstract

Non-waxy and waxy rice starches adjusted to 20% moisture (wet based, w.b.) were heated in a differential scanning calorimeter to determine the optimum parameters for producing slowly digestible starch (SDS). Starches heated to the temperature of melting (T m ) and held for 60 min in the calorimeter showed a slow digestibility compared to unheated samples. Digestibility decreased by 25 and 10%, respectively, for non-waxy and waxy rice starches relative to non-treated starches. Heat-moisture treatment of waxy corn, non-waxy corn and wheat starches at the T m determined for non-waxy rice starch did not result in significant decreases in digestibility. For waxy rice starches heat-treated in microwave or conventional ovens at the T m , there were slight but significant increases in digestibility of the treated starches compared to non-treated starches at all incubation times. Digestibility was higher for starches heated for 30 min than for 60 min. Non-waxy rice starches did not show any significant changes in digestibility. Heat-moisture treatment at the T m and the holding time of sample at that temperature in a differential scanning calorimeter were found to be significant to the formation of slowly digestible heat-moisture treated starch.

Impact of annealing and heat-moisture treatment on rapidly digestible, slowly digestible and resistant starch levels in native and gelatinized corn, pea and lentil starches

“…starch crystallites. Decreased enzyme hydrolysis on HMT (due to interaction between starch chains) has been reported for wheat, lentil (Hoover & Vasanthan, 1994b), corn, waxy corn (Franco, Ciacco, & Tavares 1995), and rice starches (Anderson, Guraya, James, & Salvaggio, 2002). The increase in RDS and decrease in SDS on HMT may have been due to disruption of double helices forming the starch crystallites at the granule surface and/or to crystallite reorientation, which was evidenced by a decrease in gelatinization enthalpy (Table 2), loss of birefringence (Fig.…”

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

“…These decreases were higher in normal maize (1.6%) and amylomaize (1.8%) starches than in waxy maize (0.2%) and dull waxy maize (0.8%) starches. There were slight but significant increases in the digestibility of the HMT waxy rice starches, whereas normal rice starches did not show any significant changes in digestibility compared to nontreated starches (Anderson et al, 2002). The discrepancy in these data lead to the realization that a more pronounced increase in enzyme digestibility of the normal rice and potato starches by HMT compared to that of the waxy type starches might be cultivar specific (interplay of several changes of starch granules), rather than direct correlation to the presence or absence of amylose in the samples.…”

“…HMT affected the a-amylase digestibility of both normal and waxy corn starches (decreased or increased depending on the moisture content of starches during treatment) (Franco et al, 1995;Kweon et al, 2000). On the other hand, a slight increase or no change in digestibility was found for waxy and normal rice starches, respectively (Anderson et al, 2002). These data indicated inconsistent results of the influence of HMT on waxy and normal starch properties, even from the same botanical source.…”

“…The maximum viscosity decreased with increases in the moisture content of starches (18%, 21%, 24% and 27%) but variations were more evident for normal corn starch. Significant decrease in paste viscosities of normal and waxy rice starches after heat treatment of starches with a moisture content of 20% at 140°C for 60 min was reported by Anderson et al (2002). Kweon et al (2000) have shown that the water-retention capacity of normal corn starch was noticeably increased (magnitude of the increase depended on the moisture content of starch during treatment), whereas that of the waxy corn starch was unchanged after heat treatment at 110°C for 16 h. A similar finding was reported by Franco et al (1995).…”

Structural characteristics of low-glycemic response rice starch produced by citric acid treatment

“…SDS content in starch was increased by treatment with debranching enzymes (Guraya, James, & Champagne, 2001;Shi, Cui, Birkett, & Thatcher, 2003;Shin et al, 2004a). Also, physical modifications have been used to increase the amount of SDS in starch (Anderson, Guraya, James, & Salvaggio, 2002;Shin, Kim, Ha, Lee, & Moon, 2005;Shin, Woo, & Seib, 2003).…”