Correlation between electrical conductivity and quality change of grass carp fillets during frying process

The correlation between electrical conductivity and quality change of grass carp fillets during frying process was investigated.The change rules of electrical conductivities adapted to current direction in 100 k Hz were determined by LCR impedance instrument. The changes of moisture and fat contents,color value and texture value of grass carp fillets were measured during frying process,and they were fitted with the electrical conductivity. The electrical conductivity of fish fillets were measured separately for parallel and series types according to the current direction,and the parallel type( direction of current in fish) of grass carp fillets had a higher electrical conductivity value than the series type( maximum difference value was 0.15 S/m).The muscle membrane connecting fiber had a major influence on electrical conductivity of two different types of muscles.With the increasing of frying time( 180 ± 2 ℃,form 0 to 4 min),the electrical conductivity,moisture content and brightness value of fish fillets were decreased,while fat content,redness value,yellow value,hardness and chewiness were increased. The electrical conductivity showed good correlations with quality indexes of grass carp fillet,and the correlation coefficients were larger than 0.95. These results provided the feasibility to determine the quality change of grass carp fillets during frying process based on electrical conductivity,and the basic data and fundamental principles for fried grass carp fillets processing during new process methods such as ohmic heating and for other freshwater fish products deep-processing.