| Currently,the addition of various microbial fermenters to bacon is becoming a focus of research,and Sichuan,as a region with a wide variety of cured bacon products,has become one of the hot topics nowadays to seek more types of microbial fermenters to improve the quality of bacon in Sichuan.In this paper,we use commercial Saccharomyces cerevisiae;as a microbial fermenting agent,study its fermentation ability and add it to bacon,and study the changes of physical and chemical properties,microorganisms and flavor substances of bacon at different stages of production and processing,aiming to provide theoretical reference for brewer’s yeast to become a new type of Sichuan bacon microbial fermenting agent and industrial production.(1)Saccharomyces cerevisiae has the ability to degrade proteins,lipids and nitrites under the addition of 15～35℃,and it increases with the increase of incubation temperature.Saccharomyces cerevisiae can promote the decomposition of proteins and the increase of free amino acids during the curing process,and has the ability to inhibit protein oxidation to a certain extent.The number of yeast in the test group increased with the increase of curing time and temperature,and no yeast was detected in the control group.The optimal curing condition for bacon in the curing stage by entropy power method was 18h at 30°C.(1)During the air-drying process of bacon,yeast and colony count,lactic acid bacteria,soluble protein,free amino acid were highly significantly positively correlated(P<0.01),and POV and b value were highly significantly negatively correlated(P<0.01),and at the end of air-drying,bacon in experimental group had special flavor substances such as 3-methyl-1-hexanal,3-methyl-1-hexanol,octyl formate and 2,5-heptanedione.(3)During the storage process,the p H of bacon did not change much,and the overall trend was to increase first and then to decrease,and the p H of experimental group changed from 6.13 to 6.05;the a_wof bacon continued to decrease,and the moisture content did not change much,and experimental group was lower than control group;the TBA of bacon continued to increase,and the mean values of TBA of experimental group and control groups during storage were 0.136 mg/kg,0.175The sodium nitrite content of bacon gradually decreased,and the experimental group was significantly lower than the control group in the first 60 d of storage(P<0.05),and the difference was not significant in the later storage process;the histamine content of bacon increased with time,and the experimental group was significantly lower than the control group in storage(P<0.05),and the increase in the experimental group was 14.08%lower than the control group.Compared with the control group,the increase in the experimental group was 14.08%lower than that of the control group;the L and b values of bacon gradually increased and the a value decreased,and the color difference stability of the experimental group was better;no yeast was detected in the control group,and the total number of cocci,lactobacilli and colonies showed a trend of increasing and then decreasing with the increase of storage time.(4)During the storage of bacon,a total of 90 volatile flavor substances were detected,including 19 aldehydes,18 alcohols,18 esters,19 hydrocarbons,5 acids,and 11 others,and the absolute content of all volatile flavor substances was 188638.53μg/kg,of which the highest absolute content of flavor substances was aldehydes,totaling 116479.19μg/kg,accounting for 61.75%of the overall flavor substances,followed by esters in the experimental group,totaling 25648.01μg/kg,accounting for24.63%of the flavor substances in the experimental group,and hydrocarbons in the control group,totaling 6943.21μg/k,accounting for 8.21%of the flavor substances in the control group.The overall flavor change pattern of bacon increased with storage time.In the experimental group,a total of 26 key volatile flavor substances were identified among 90 flavor compounds using the odor activity value(OAV)method,with the contribution of aldehydes being more prominent,followed by esters.By principal component(PCA)analysis,it was clear that the experimental group of bacon had active flavor changes from 20 to 60 d,while phenylethanol,mushroom alcohol,phenylethylaldehyde,n-nonenal,benzaldehyde,ethyl hexanoate,(E)-2-heptenal,n-hexanol,n-hexanal,and 2-undecenal were typical flavor substances,and by partial least squares discriminant analysis(PLS-DA)analysis,it was clear that the experimental group during storage had 4 of key flavor substances,namely,phenethyl acetate,phenylethanol,1-octen-3-one,and ethyl caprylate,and1-octen-3-one was the most critical flavor substance. |
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