Abstract:

The purpose of this work is to compare the physico-chemical properties of collagen extracted from tilapia skin by
different methods, hot water extraction, acid extraction and ultrasonic-assisted enzymatic extraction. The collagens exhibited
distinctive absorption peaks in the wavelength range of 220–232 nm. There was no significant difference in the contents
of hydroxyproline or praline. Gel strength of collagen extracted with hot water was higher than that from other extraction
methods, while intrinsic viscosity of collagen extracted with citric acid was the highest. The denaturalization temperature of
tilapia skin collagen was about 31 ℃ regardless of extraction methods. The isoelectric point (pI 5.9) of collagen extracted
with hot water was lower than that (pI 7) of collagens extracted by other methods.

Key words: tilapia skin, collagen, extraction, physico-chemical properties