Antistaling of rice starch in a gel model system and Korean rice cake: the role of wheat flour in retrogradation-retardation technology

Modifying the internal structures of steamed rice cakes by emulsifiers for promoted textural and sensory properties

Steamed rice cakes (SRCs) are traditional Chinese snacks with a wide territorial acceptability. However, traditional cuisine is challenged by insufficient expansion of the spongy network favoring tasting experience. In this study, the effects of different emulsifiers on the physical, pasting, and textural properties of SRCs were investigated. The results showed that the emulsifiers, especially sodium stearoyl lactylate, interacted with starch molecules to form starch-lipid complexes, which created gels with enlarged spacing between junction zones. The electrostatic repulsion prevented aggregation of starch chains, yielding loosely packed microstructures of rice batter. As a result, the SRCs with 0.5% addition (relative to the weight of rice flour) of emulsifiers had increased specific volume, decreased apparent porosity and hardness, and preferable springiness, contributing to desired overall acceptability when receiving sensory evaluation by a group of trained panel. The results demonstrated the feasibility of modifying the textural properties of starch-based foods.

Characteristics of wheat starch-pectin hydrolysate complexes by dry heat treatment

The objective of this study was to characterize dry heat-induced wheat starch-pectin hydrolysate (WST/PH) complexes to develop the retrogradation-retarded starch. Native (N-) and protease-treated (P-) WST were used as starch sources. Pectin hydrolysates were mixed independently with N-WST and P-WST to a mixing ratio of 49:1 (based on total solid contents), followed by drying below 10% moisture and dry heat treatment at 130 °C for 4 h. The molar degrees of substitution (MS) was higher for WST/PH complexes than its mixtures, and apparent amylose contents decreased with their MS. Relative to WST/PH mixtures, solubilities were higher for WST/PH complexes, while swelling powers didn't differ. WST/PH complexes showed the lower degree of retrogradation, setback viscosities, slowly gelling tendency, and syneresis. These phenomena were more pronounced in WST/PH mixtures and complexes prepared with P-WST. Overall results suggest that dry heat-induced WST/PH complexes could be a potential retrogradation-retarded starch to replace chemically-modified starches.