Hydrocolloids-aided control of oil penetration and distribution in deep-fried breaded fish nuggets

To investigate the effect of hydrocolloids on oil penetration and distribution in fried batter-breaded fish nuggets (BBFNs), sodium carboxymethyl cellulose (CMC-Na), guar gum (GG), and xanthan gum (XG) were individually blended (0.2 or 0.3%, w/w) into the mixture (1:1, w/w) of wheat gluten (WG) and wheat starch (WS) to form batters. The moisture absorption capacity of XG was found to be the highest, followed by CMC-Na, GG, WG, and WS. Hydrocolloids increased the batter viscosity, shear modulus, WS gelatinization and WG denaturation temperatures, BBFNs pick-up, thermogravimetry temperature, and the bound water content in crust. This trend was opposite with enthalpy change (ΔH) during starch gelatinization and protein denaturation, both of which lessened pores and cracks, leading to an inhibition of oil penetration into fried BBFNs. Of the three hydrocolloids, XG exhibited the greatest effect, followed by CMC-Na and GG. Therefore, XG was suitable for reducing fat content of fried BBFNs. Overall, the hydrophilic and thickening capabilities of the three studied hydrocolloids and their interactions with WS and WG altered the batter characteristics and reinforced the thermal stability of the crust, thereby reducing oil penetration and distribution in deep-fried BBFNs. This work will not only provide new ideas to clarify oil penetration based on hydrocolloids for fried BBFNs, but also provide scientific instructions for the large-scale production of low-fat fried batter-breaded foods.