Effect Of Lactobacillus Plantarum With Antioxidant Properties On Protein,Fat Oxidation And Product Quality Of Fermented Sausage

Proteins and fats are easily oxidized during the production and storage of fermented meat products,resulting in deterioration of products.In this study,Lactobacillus plantarum P3 with good antioxidant properties was screened and mutagenized.The non-inoculated Lactobacillus plantarum group was used as the control group（CK）,the starting strain P3 and the mutant strain P3-M2 were used as the experimental group,and were respectively recorded as the WS group and the MS group.They were applied to fermented sausages to investigate the effects of antioxidant Lactobacillus plantarum on the oxidation degree of fat,protein,physicochemical properties and flavor changes during the production and storage of fermented sausages.The results were as follows:1.Antioxidant Lactic acid bacteria screening and mutation breedingIn this study,the strain P3 with antioxidant capacity was selected from 42meat-derived lactic acid bacteria strains.Mutation breeding of P3 was performed to obtain a mutant strain P3-M2 with significantly improved comprehensive antioxidant capacity,T-AOC value of P3-M2 was（30.85±0.67）U/m L,which was 33.78%higher than that of P3（P<0.05）.The hydroxyl radical scavenging ability of P3-M2and P3 fermentation broth did not change significantly（P>0.05）.The DPPH radical scavenging ability,Fe²⁺chelating ability,and superoxide anion scavenging ability of strain P3-M2 fermentation broth were significantly improved（P<0.05）.It showed that the mutant strain P3-M2 significantly improved the ability of scavenging free radicals and the antioxidant capacity.2.The effects of antioxidant Lactobacillus plantarum on the oxidation of sausage fat.With the extension of fermentation time,the TBARs values of the three groups of sausages gradually increased,and showed CK>WS>MS.The POV values gradually increaseed,but the POV values of the three groups of sausages could not be accurately compared.The lipoxygenase LOX activities of MS group on 4 d,22 d and28 d was significantly lower than that of WS group（P<0.05）,and LOX-catalyzed oxidation decreased.Strain P3-M2 could effectively slow down the oxidation of fat in sausages.3.The effects of antioxidant Lactobacillus plantarum on the oxidation of sausage protein.The sulfhydryl content of sarcoplasmic protein and myofibrillar protein gradually decreased,and showed MS>WS>CK;The carbonyl content gradually increased,and showed CK>WS>MS;The surface hydrophobicity gradually increased,and showed CK>WS>MS;The content of Met Mb of methemoglobin increased gradually,and showed CK>WS>MS;The results of SDS-PAGE electrophoresis showed that both the sarcoplasmic protein and myofibrillar protein of the sausage were degraded during the fermentation process,and the degradation degree of the sarcoplasmic protein was more obvious.These results indicated that strain P3-M2could effectively reduce the protein oxidation in sausage.4.Effect of antioxidant Lactobacillus plantarum on the physicochemical properties of sausageWith the extension of fermentation time,the pH value of sausage decreased,the rate of decline was MS>WS>CK;the water was gradually lost,and there was no significant difference between WS group and MS group（P>0.05）;The addition of strain P3-M2 significantly slowed the decrease of the L*value of the sausage in the experimental group（P<0.05）,and the a*value did not decrease significantly（P>0.05）;The texture characteristics did not change significantly（P>0.05）.It showed that strain P3-M2 had the effect of protecting the redness value a*and yellowness value b*of sausage,slowing down the darkening of sausage color,while strains P3and P3-M2 had little effect on texture.5.Effect of antioxidant Lactobacillus plantarum on flavor of sausageSausages formed a special flavor during fermentation.GC-MS detected a total of153 volatile substances.The type of esters in sausages of MS group increased from 16to 20,and the relative content increased by 17.13%,indicating that Lactobacillus plantarum P3-M2 contributes to the production of flavor substances.In summary,adding P3-M2 with strong antioxidant capacity to sausage could reduce the oxidation of fat and protein during fermentation,protect the stable natural structure of protein,and simultaneously improve the quality of sausage and promote the sausage to form a better flavor.