Explore the oil penetration of breaded fish nuggets during deep-fat frying based on the surfactant effect theory: Effect of frying temperature and oil unsaturation

Insight into the impacts of frying temperature and oil unsaturation on oil oxidation and penetration is crucial for breaded fish nuggets manufacturing. The batter-breaded fish nuggets (BBFNs) were fried for 150 s at 140-200 degrees C using four vegetable oils. The increase in polar compounds content, viscosity and dielectric constant of oil indicated that oil oxidation was aggravated by frying temperature and oil unsaturation. Furthermore, the increased porosity of fried BBFNs confirmed that oil oxidation contributed to the formation of pores. Consequently, the contact angle and interfacial tension between the oil and crust were lowered, the increased penetrated oil content, strong red fluorescence intensity as well as a wide range indicated that oil penetration in the fried BBFNs was promoted. This study has provided new evidence for oil penetration based on the surfactant effect theory.