Waxy corn

Abstract: The effect of sodium hypochlorite on the physicochemical and functional properties of normal and waxy corn starches was investigated in this study. It was found that both carboxyl and carbonyl contents of oxidized starches from normal corn were higher than those of waxy corn. The introduction of carboxyl and carbonyl groups resulted in lower amylose content and swelling power. Both amylose and amylopectin were oxidized and degraded during oxidation but amylose was more susceptible to oxidation. Studies conducted on paste clarity revealed that the percentage transmittance increased after oxidation. The morphology of the starches was not altered after oxidation. Thermal properties measured by differential scanning calorimeter, showed that oxidation reduced transition temperatures (onset temperature, T o ; peak temperature, T p ; and conclusion temperature, T c ), gelatinization and retrogradation enthalpies of both normal and waxy corn starches. The retrogradation tendency was reduced after oxidation both in normal and waxy corn starches. Oxidation produced waxy starch with significantly higher peak ( P V ), trough ( T V ), breakdown ( B V ), final ( F V ), and setback viscosity ( S V ) as demonstrated by using a rapid visco analyzer. Oxidation reduced the pasting temperature of both normal and waxy corn starches. Also, the principal component analysis (PCA) study was conducted to find the overall variations among the oxidized starches studied. Together, the first two components represent 88.7 g/100 g of the total variability.

Abstract: Resistant starches (RS) were prepared by phosphorylation of wheat, waxy wheat, corn, waxy corn, high-amylose corn, oat, rice, tapioca, mung bean, banana, and potato starches in aqueous slurry (≈33% starch solids, w/w) with 1–19% (starch basis) of a 99:1 (w/w) mixture of sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) at pH 10.5–12.3 and 25–70°C for 0.5–24 hr with sodium sulfate or sodium chloride at 0–20% (starch basis). The RS4 products contain ≤100% dietary fiber when assayed with the total dietary fiber method of the Association of Official Analytical Chemists (AOAC). In vitro digestion of four RS4 wheat starches showed they contained 13–22% slowly digestible starch (SDS) and 36–66% RS. However after gelatinization, RS levels fell by 7–25% of ungelatinized levels, while SDS levels remained nearly the same. The cross-linked RS4 starches were distinguished from native starches by elevated phosphorus levels, low swelling powers (≈3g/g) at 95°C, insolubilities (<1%) in 1M potassi...

Abstract: Japonica (Tainung 67 [TNu67]) and waxy (Taichung 70 [TCW70]) rice, normal and waxy corn, and cross-linked waxy rice and corn starches were used in an investigation of the influence of the granular structure on the pasting behavior of starch, using small amplitude oscillatory rheometry. Both normal corn and normal rice (TNu67) starches had the highest storage moduli (G′), followed by their cross-linked versions; native waxy corn and rice starches had the lowest. Native waxy starches showed paste characteristics (G′ 0.2) at concentrations of up to 35%. However, cross-linked waxy starches exhibited gel behavior at 10% concentration (cross-linked TCW70) or higher (cross-linked waxy corn starch). The degrees of swelling power were in the order: TCW70 > native waxy corn > TNu67 ≅ cross-linked TCW70 ≅ normal corn ≅ cross-linked waxy corn starches. Solubilities were in the order: normal corn > TNu67 > native waxy > cross-linked waxy starches. The addition of 2% purified amylose from ind...