Unraveling enhanced crispiness in fried fish with wheat flour-based batter coating: multiscale structure, protein...

The improving effect and mechanism of a wheat flour (WF)/corn starch (CS) composite batter coating on the crispiness of fried fish were investigated. Fourier-transform infrared spectroscopy, X-ray diffraction, and rotational rheometry were used to characterize the blend flour structure, batter viscoelasticity, and quality attributes of the fried products. The results showed that with an increase in the CS ratio, the blended flour showed increased hydrogen bonds, short-range structural order, crystallinity, enthalpy change, and hydration properties. In comparison to the single-component CS batter, the water retention, viscosity, disulfide bonds, and pickup of the WF/CS composite coating at a 1:1 ratio increased by 12.2%, 6-fold, 10-fold, and 93.2%, respectively. At a 1:1 ratio, a dynamic equilibrium was achieved between the continuous network structure of WF and the filling effect of the CS particles. Application of the composite batter coating to fish led to increases in both color and texture of the products. Compared to the pure WF, samples coated with the 1:1 WF/CS batter exhibited increased hardness, crispiness, and brittleness after holding for 0, 30, and 60 min of 14.3%, 33.3%, and 40.5%; 53.3%, 25%, and 42.8%; and 27.1%, 51.4%, and 27.3%, respectively. During frying, compared to single-component batter, 1:1 WF/CS coated products exhibited more uniform the water and oil distribution, as well as decreased oil absorption and number of large pores. Therefore, the compact composite coating acted as a barrier, inhibiting mass transfer and thereby improving crispiness. This study provides deeper insights into the quality improvement mechanism of fried battered foods.