Reaserch On Quality Changes During Processing Of Ready-to-eat Loach And Product Development

Loach is nutritious and contains many nutrients required by the human.This thesis used loach as material to develop a spicy loach product,optimized the processes of thawing,deodorization,frying and sterilization,studied the effect of repeated frying on the quality of palm oil and product,and determined the nutrient content and shelf life of the product.The effects of five thawing methods on the physicochemical properties and structure of frozen loach were studied.The results showed that the flow thawing had the least influence on the thawing loss rate and cooking loss rate,and the loss of soluble protein was low.The thawed loach muscle fibers were closely arranged and the total relaxation area was the largest.It was determined that the flow thawing was the best method.Using sensory scores as the indicator,the single-factor and orthogonal experiments were used to obtain the dislocation formula.The deodorant formula based on perilla solution(1%)was sugar 5%,green tea solution 10%,pepper solution 2%,salt 5%,and raw soy sauce 2.5%,Rice wine 10%,yeast 0.08%,the ratio of material to liquid was 1:1.5,and the dislocation time was 2 h.The results of gas chromatography-mass spectrometry showed that the astringent components were mainly derived from alcohols and aldehydes,and the content of alkanes,olefins,aromatics and some other compounds increased after deodorization,while the alcohols and aldehydes showed a significant decrease.Using the sensory score as the indicator,determined the frying temperature was 170℃ and frying time was 3 min.The effect of repeated frying on the quality of palm oil and loach extract oil showed that the color difference,peroxide value,acid value,2-thiobarbituric acid and p-anisidine value increased as the increasing of frying times.Saturated and unsaturated fatty acids of palm oil were more stable,while the content of saturated fatty acid of loach extract oil increased significantly and unsaturated fatty acids decreased dramatically.Based on the comprehensive scores of colony number and peroxide value,the optimal conditions for microwave sterilization which through the optimization of the response surface were that microwave power was 240 W,microwave time was 17 s,and material quality was 11.3 g.The loach was fried by using the palm oil which already used three times and the pearson coefficient of peroxide value,acid value were respectively calculated with sensory score.The key factor affecting product quality was determined as the peroxide value.The theoretical value of the shelf life of the product was 265 d stored at 20℃ calculated by the arrhenius equation.