| With the development of fisheries,surimi products has also increased year by year.Adding microbes to the surimi made into fermented surimi.After fermentation,the protein,fat,and carbohydrates of the surimi change differently,the value of nutrition improved and special flavor and taste are formed.The fish sufu was produced by fermentation of fish tofu through inoculating with Mucor and Monascus.The fermentation process and the change rules of the components during fermentation were studied.The main results are as follows:(1)Monascus F1 was isolated from red sufu.Combined with the morphological analysis and molecular biology character,the strain F1 was identified as Monascus purureus.Red yeast rice was produced using strain F1,and the color price was measured during red yeast rice production.On the 7th day of fermentation,the color of red yeast rice was purple,and the color price was 1293 U/g.(2)The pre-fermentation process conditions of fish sufu was optimized with response surface method using the protease activity as the evaluation index.The results showed that the optimum pre-fermentation time was 103 h,the fermentation temperature was 27℃,and the inoculation amount was 5.3%,the activity of protease was 51.48U/g at the condition.By the SDS-PAGE electrophoresis results showed that most of the proteins were decomposed into small molecular peptides during the early fermentation process.The hardness,elasticity,chewiness,adhesiveness and cohesiveness were gradually decreased during the fermentation process.(3)The changes of acidity,amino acids nitrogen,and free amino acid during the fermentation of fish sufu were analyzed.During the pre-fermentation process of fish sufu,the acidity and amino acid nitrogen content increased gradually from 0.16% and 0.01% to 3.19%and 0.23% respectively,and the prepared salted was reduced to 1.78% and 0.14% respectively.The content of acidity and amino acid nitrogen increased to 3.19% and 0.35% respectively after adding Monascus F1 at the late stage of maturation.The content of delicious amino acids,essential amino acids,hydrophobic amino acids,and total amino acids in the fermentation process increased gradually.At the end of the fermentation,the contents reached respectively to138.57 mg/100 g,491.68 mg/100 g,340.06 mg/100 g and 915.77 mg/100 g.(4)Using GC-MS the volatile components were analyzed during the maturation of fish sufu.A total of 83 compounds were detected.There were 42 species,60 species and 53 compounds were detected respectively at the salted stage,14 d and 28 d of late fermentation.The content of each component also changed.The contents of esters and acids increased from 5.20% and 2.02%to 52.28% and 4.01% respectively,while alcohols,ketones,alkenes,alkanes,phenols and the content of other substances decreased significantly during fermentation.The contents decreased from 74.59%,8.7%,7.55%,0.77%,0.51%,and 0.66% in the salted stage to 33.20%,0.45%,0.27%,0.14%,0.22%,and 0.25% respectively after 28 d ripening. |
