Study On Preparing Fish-like Flavoring Using Catfish's Head

Using protein as material to prepare protein hydrolysate, thermal process in high temperature based on protein hydrolysate as raw material was an important route to prepare flavouring. Choosing catfish's head as main raw material in this paper, the effect of some factors on the hydrolytic condition, the right amino acid, the influential factors on Maillard reaction and flavoring's preparing was investigated thoroughly.There were many factors affect the hydrolytic reaction of catfish's head, first of all, testing these factors one by one so as to gain the possibly area, then choosing the appropriate enzyme, It was found that Flavourzyme plus Protamex together were best for hydrolyzing catfish's head. Orthogonal experiment was applied to optimize the best hydrolysis conditions for Flavorzyme and Protamex on catfish's head. The results showed that the optimum conditions for catfish's head were as follows: catfish's head 10g, Protamex 0.08g, Flavourzyme 0.06g, distilled water 20ml, pH8.0, then put them in 50℃electric-heated-shaked thermostatic water bath for 4 hours.Making a electrophoretic experiment of Tricine-SDS-PAGE on catfish's head protein hydrolysate, there were 4 marks in the running gel, and the fourth marks was very wide, where congregated vast amounts of low moleculer polypeptide, amino acid and other compounds, the molecular weight of these compounds were below 7000 D, and these compounds were important precursor substances in flavouring.There were some fishy smell compounds and acrid polypeptide compounds in the protein hydrolysate. Adding right amount Yeast extract could not only covering up the fishy smell and bitterness, but also strengthening the mellow fragrance of hydrolysate. The experiment showed that the optimal quality was 0.25g/10ml.Making a great deal of preparatory experiments so as to find the important contributing reducing sugar, amino acid and several other materials in Maillard reaction. Some primary factors influenced the flavour substances obviously, such as reaction time, initial pH, the quality of V_B1, the quality proportion of glucose and xylose and ratio of liquid to solid. On the basis of single factor analysis to these factors, Orthogonal experiment was applied to optimize the reaction conditions. The results showed that the optimum conditions for catfish's head hydrolysate in Maillard reaction were as follows: Glucose 0.36g, Xylose 0.54g, Glycin 0.1g, L-Glutamic acid 0.1g, L-Cysteine hydrochloride 0.2g, L-Alanine 0.1g, L-Proline 0.1g, V_B1 0.3g, reaction 50 minutes, initial pH 7.5, ratio of liquid to solid 50%, V_C 0.1g, Nacl 0.1g. Some factors influenced the Maillard reaction remarkably, such as L-Cysteine hydrochloride, the quality proportion of glucose and xylose and reaction time. Under this condition, the fish-like flavouring smelled full-bodied and tasted delicious.Extracting and condensing the fish-like flavouring, GC-MS was used to identify the compounds composition. 45 kinds of compounds were identified from the flavouring, thereinto, furan, furanones, furanose, thiazoles, pyrazine, alkyl-pyrazine, pyrrole, alkyl-pyrrole and other important aldehyde, ketone, alkene-aldehyde, alkene-ketone, ester, organic acid, alcohol and other low moleculer compounds were identified, which were all contributed to fish-like flavouring.Flavours were added into the Maillard reaction flavouring, the fish-like flavouring smelled more fragrant and tasted more delicious.