Study On The Antioxidant Activity Of MPRs Prepared By Enzymatic Pig Bone Meal And The Process Of Meat Flavor

Pig bone meal was used as raw material in this paper, the degree of hydrolysiswas used as the indicator, the enzymatic effects on pig bone meal of alkalineprotease, neutral protease, papain and animal protease were compared, the bestprotease-alkaline protease was filtered out, the effects of enzyme dosage, initialpH, time, temperature and solid-liquid ratio on the degree of hydrolysis wereinvestigated. The response surface method was utilized to optimize the enzymatichydrolysis process conditions on pig bone meal. The result showed that the optimalconditions of enzymatic hydrolysis for pig bone meal were that enzyme dosage was5722.25U/g, temperature was59.12℃, the initial pH was7.96and the enzymatictime was3.19h, under the conditions, measured the degree of hydrolysis was17.13%.Using the optimal enzymatic hydrolyzate of pig bone meal above mentioned asraw material，a reducing sugar (glucose or xylose) was added to simulate the easyMaillard reaction system, DPPH scavenging rate was investigated to analyse theantioxidant capacity of the products. The results showed that: the optimalconditions of glucose-MRPs were that: the reaction time was4h, initial pH was6.5and temperature was120℃, glucose dosage was1.5%, under this condition,DPPH radical scavenging rate was82.53%. The optimal conditions ofxylose-MRPs were that: the reaction time was3h, initial pH was7.5andtemperature was120℃, the xylose dosage was1.5%, at this point, DPPH radicalscavenging rate was88.58%. DPPH radical scavenging ability of xylose-MRPswas higher than glucose-MRPs’. As far as glucose-MRPs and xylose-MRPs wereconcerned, as compared with the H-MRPs and M-MRPs and unseparated MRPs,L-MRPs had the strongest reducing ability, and H-MRPs had a higher hydroxylradical scavenging ability than others.Under the optimal enzymatic process of pig bone meal conditions, pork flavorwas obtained by thermal reaction. The effects of the amino acids species, reducingsugars species, reaction temperature, reaction time and starting pH on the flavor ofthe products were studied. Through sensory evaluation method and thedetermination of absorbance values at420nm and280nm, it was determined thatL-cysteine and the mass ratio of1:1of glucose and xylose, denoted as G+X(1:1)were chosen. On the basis of the single factor, orthogonal experiment was chosen tooptimize the process. The best pork flavor process were that initial pH was7, temperature was115°C, the reaction time was60min, the dosage of G+X (1:1) was4%, L-cysteine dosage was0.3%and thiamine dosage was0.2%. The aroma ofproducts was pure and realistic.Flavor was extracted by HS-SPME and GC-MS was used to isolate andidentify these substances. The analysis results showed that there were85kinds ofvolatile compounds, including11kinds of alcohols and phenols,8kinds ofaldehydes,13kinds of ketones,5kinds of acids,11kinds of esters,21kinds ofhydrocarbons,16kinds of heterocyclic compounds, respectively. Aldehydes,ketones,esters, acids and heterocyclic played major roles for pork flavor,representing substances were cycleopentanone, heptanal, dodecane-6,7-dione,octanoic acid, nonanoic acid, s-methyl thionexanoate, furfural,2,3,5-Trimethylpyrazine,2-methyl-3-furanethiol, ethylene mercaptan and4-methyl-5-thiazoleethanol.