The gel prepared by Nemipterus virgatus (N. virgatus) surimi alone still has some defects in texture and taste. Complexing with polysaccharides is an efficient strategy to enhance the gel properties. The main objective of the study was to analyze the relationship between the gel quality and molecular interaction of N. virgatus surimi gel after complexing with tapioca starch. The results make clear that the gel strength, hardness, and chewiness of surimi gel were increased by molecular interaction with tapioca starch. At the appropriate addition amount (12%, w/w), the surimi gel had excellent gel strength (17.48 N), water holding capacity (WHC) (89.01%), lower cooking loss rate (CLR) (0.95%), and shorted T2 relaxation time. Microstructure analysis indicated that the addition of tapioca starch made the surimi gel evenly distributed in the gel network structure, resulting in a significant reduction in cavities diameter, and the minimum diameter could be reduced to 20.33 μm. In addition, tapioca starch enhanced the hydrogen bond and hydrophobic interaction in the gel system and promoted the transformation of α-helix to β-sheet (P<0.05). Correlation analysis showed that the increased physicochemical properties of surimi gel was closely related to the enhanced non-covalent interactions. In conclusion, the non-covalent complexation with tapioca starch is an efficient strategy to enhance the gel quality of surimi gel.

The flow behavior of the administrated fluid matrices demands careful assessments for stability as consumed by individuals with dysphagia. In the present study, we incorporate tapioca starch (TS), hydroxypropyl distarch phosphate (HDP), and xanthan gum (XG) as thickeners into different nectars (300±20 mPa.s) undergoing thermal processing and evaluated their stability. The thickened nectars presented better water holding and oil binding capacities at 25 ℃ than 4 ℃, and the nectars with TS provided the best results for both capacities as well as the highest solubility index and swelling power (p<0.05). All prepared nectars appeared to be shear-thinning fluids with yield stress closely fitting the power law and Casson models. XG-contained nectars presented a higher yield stress and consistency index. Matrices thickened by HDP exhibited a higher viscoelastic property compared to those thickened by TS during thermal processing. TS nectars presented viscous behavior, whereas HDP and XG nectars presented elastic behavior at 80 ℃ processing. The 3-min thermal processing HDP-nectars remained stable and met dysphagia-friendly requirements under 4 ℃ storage for 28 days regardless of the types of fluid bases (distilled water, sport drink, or orange juice). The employed thickeners present adequate physicochemical properties to be potentially utilized for producing dysphagia-friendly formulations.