| A large quantity of animal bones will be left as by-products during processing in livestock and poultry slaughtering enterprises, animal bones and small amount of meat attachment showed high application value. Using these animal skeletons reasonably and effectively can not only be friendlier to environment but also be beneficial to enterprises. In this thesis, studies focusing on preparation of natural meat flavoring essence from pig bones were preceded.Pig bone contains rich nutrients, including protein, fat and minerals. By determing the basic ingerdinets, fresh pig bone contains17.4%of protein,23.8%of fat,29.1%of ash content and30.8%of moisture. In order to fully extract nutrients from pig bone, this experiment used high temperature and high pressure to extract protein and fat from pig bone. Effects of cooking time, temperature and soild/liquid ratio on protein extract ratio and bone oil extract were studied using orthogonal array design. Results showed that the optimal technological parameters of cooking were as follows:130℃of cooking temperature,3h of cooking time,1:1.5(mL/g) of solid/liquid ratio. Under these conditions, protein extract ratio and bone oil extract ratio were68.2%and83.3%.Flavourzyme, Protamex, Alcalase, Papain were used to evaluate their enzymolysis effects on pig bone soup. And the result showed that among which Flavourzyme has the best enzymolysis effect, while Papain has the worst effect. In order to obtain the best enzymolysis effects and hydrolysis with good flavor, four types of enzyme were assembled doubly. Comparison analysis found that little amount of free amino acids existed in raw bone soup, whereas after enzymolysis its concentration in bone soup increased apparently. Especially treated by Flavourzyme and combinatory enzyme, in hydrolysis product flavor amino acids and sulfur containing amino acid showed high content. The concentration of Cysteine is788.94mg/100ml and the concentration of methionine is1019.13mg/100ml. Therefore, conclusion can be drawn that this combinatory enzyme method was the most appropriate for preparation of meat flavoring essence through maillard reaction.Hydrolysis conditions of flavourzyme and protamex had been optimized using center composite design of quadratic regression orthogond. And one of the best hydrolysis conditions was as followed:45℃of temperature,7.09of pH value,5.24h of enzymatic hydrolysis time,10.06%of concentration of protein. Under these conditions, the degree of hydrolysis of enzymatic bone soup is up to21.32%.After concentration of hydrolysis liquid by processes mentioned above, meat flavoring essence was prepared by Maillard reaction. Firstly, single factor test was proceeded to ascertain the substrate addition and reaction conditions range of Maillard reaction. Through Friedman sorting analysis, reaction time, temperature and fat were found to affect the process of meat flavoring essence preparation apparently. Optimization of Maillard reaction key factors were carried out by orthogonality test and the best prescription was ascertained. Following this prescription, meat flavoring essence was prepared, and then GS-MS was used to analyze and identify meat flavoring essence.25kinds of savor compounds was detected totally, including2kinds of alkanes, one kind enol,6kinds of ketone, one kind of aldehyde,3kinds of acids, one kind of phenol,9kinds of heterocyclic compounds,2kinds of sulfur containing compounds. Heterocyclic compounds such as2-Pentylfuran、5-methyl-2-thiophene and carbonyl compounds have an important meaning of contribution for meat flavor. Results showed that enzymolysis liquid of pig bone through heat reaction has a strong meat flavor and feature savor. |
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