Mass transfer and texture characteristics of fish skin during deep-fat frying, electrostatic frying, air frying and vacuum frying

Abstract

Fried fish skins are snacks with rich flavor in Asian. However, the high fat content about 50% is not good for health. It is possible to reduce the oil content while maintain its fried taste and texture by optimized frying methods. The effects of different frying approaches such as air frying, vacuum frying, electrostatic frying and traditional deep-fat frying on the oil uptake, moisture loss, breaking force, color, and microstructure attributes of fried fish skins were studied. Air and oil frying were performed at 180 degrees C for 2-12 min. Vacuum frying was conducted at lower temperature 120 degrees C for 4-24 min. Results showed that air fried and vacuum fried fish skins had the lowest fat contents (9.8% and 27.7%, respectively) and showed smooth, uniform microstructures. On the contrary, holy, irregular and non-uniform microstructures were obtained by traditional deep-fat frying and electrostatic frying due to high heat and rapid mass transfer occurred. The oil uptake (47.6% and 46.3% fat content, respectively) and browning reactions were also significant. Air frying developed a slower water evaporation rate and higher fish skin puffing ratio, which was suggested to be an alternative to traditional deep-fat frying.