EFFECT OF ADDING MANNERS OF SOY PROTEIN ISOLATES ON THE GEL PROPERTIES OF TILAPIA SURIMI

Effects of adding manners of soy protein isolates(SPI) on the gel properties of tilapia surimi were investigated.The strength of surimi gel increased when 2% SPI was added in wet manner,but decreased with increase of the addition amount.The strength of surimi gel decreased when SPI was added in dry manner.SDS-polyacrylamide gel electrophoresis(SDS-PAGE) indicated that protein molecules in surimi were bonded with SPI through covalent bonds in the gelation process.The addition of SPI resulted in significant decrease(P0.05) of the hardness,cohesiveness and resilience of surimi gels,but no remarkable influence(P0.05) on the elasticity and chewiness of surimi gels.The water retention property of surimi gels increased when 2% or 5% SPI was added in wet manner,but decreased remarkably(P0.05) when the addition amount of SPI increased to 10%.The water retention property of surimi gels decreased remarkably (P0.05) when 2% or 5% SPI was added in dry manner,but increased when the addition amount of SPI increased to 10%.The whiteness of the gel remarkably decreased(P0.05) when the SPI was added.