| Rabbit meat is rich in polyunsaturated fatty acids,protein and essential amino acids,and also contains less fat,cholesterol and allergens.It has gradually become an ideal meat in the national diet.However,the market is presently lacking in deep-processed rabbit meat products,which greatly hinders the further development of the rabbit meat industry.Additionally,the majority of the beef and pork jerky available on the market is made using conventional methods and has issues like a single flavor,dry and hard texture,and poor color.Incorporating microbial fermentation technology into the conventional method of making meat jerky can give meat jerky a distinctive taste and improve the texture and chewiness.As a result,this paper used fermented rabbit jerky as the research object to examine the effects of various commercial starter cultures on the physical and chemical quality of rabbit jerky in an effort to diversify the types of deepprocessed rabbit meat products and enhance the texture and sensory qualities of traditional meat jerky.A commercial starter culture was selected which was most conducive to improving the quality of rabbit jerky.Then,using shear and sensory ratings as indicators,the optimal fermentation process was identified using single-factor and response surface tests.Under optimal fermentation process conditions,the physical and chemical characteristics,flavor components of fermented rabbit jerky were investigated during five processing processes: raw meat,post-curing,post-fermentation,post-roasting and finished product.Finally,a shelf-life prediction model based on chemical kinetic equations was created after the storage quality of fermented rabbit jerky at 4°C,25°C,and 37°C was examined.Finally,the storage quality of fermented rabbit jerky at 4°C,25°C and 37°C was investigated and a shelf-life prediction model was developed using chemical kinetic equations.The main research and results were as follows:(1)Compared to the control group,the moisture content and p H value of the rabbit jerky fermented by four commercial starter cultures were reduced.The L* and b* values of the rabbit jerky barely changed after the starter culture was added,but the a* values considerably increased(P<0.05).The structural integrity of rabbit meat was compromised by microbial fermentation,which significantly reduced the shear,firmness,and chewiness of fermented rabbit jerky(P<0.05).The findings of the microstructure research supported the aforementioned assertions.By means of microbial fermentation,the flavor of the dried rabbit jerky was also improved.Further correlation analysis of the various indicators of rabbit jerky showed that the a* value was significantly positively correlated with color(P<0.05).The increase in total free amino acid content in the fermented rabbit jerky was mainly related to the increase in non-essential amino acid content,which was more conducive to enriching the flavor of the fermented rabbit jerky.In terms of sensory scores,there was a significant positive correlation between tissue state and color(P<0.05),indicating that rabbit jerky with better tissue state also had better color.In summary,the indexes of fermented rabbit jerky prepared with B-LC-78(Pediococcus lactis,Staphylococcus carnotus)starter were better and the comprehensive score of sensory evaluation was the highest.It was found to be the most effective starter among the four commercial starter cultures for fermented rabbit jerky.(2)Using shear and sensory scores as indicators,the optimum fermentation process was identified using the single factor method and response surface test: fermentation temperature of 26°C,fermentation duration of 25 h,and addition of 0.04% of fermenting agent.Under these conditions,the shear force of the fermented rabbit jerky was 49.71 N and its organoleptic score was 91.02.The predicted numbers’ relative errors were 1.34% and 1.06%,respectively.The basic physicochemical and nutritional indicators of the fermented rabbit jerky produced by the above fermentation process all met the requirements of GB/T 31406-2015 "Jerky".The nutritional profile,texture,and flavor content of the fermented rabbit jerky were all considerably better than those of the unfermented variety,and the variety of volatile flavor compounds was also significantly higher.Compared to commercially available pork jerky,fermented rabbit jerky had a higher protein and total volatile basic nitrogen content and a lower fat and thiobarbituric acid reactant substances value,meeting the original objective of developing a casual,healthy and highly nutritious fermented rabbit jerky.(3)The physicochemical properties and changes in flavor quality of fermented rabbit jerky during processing were examined under the optimum fermentation circumstances.The findings demonstrated that,with a variation range of 15.57 g/100 g to 82.00 g/100 g,the moisture content of raw meat rose slightly during the curing stage,and then decreased gradually during the following fermentation,roasting,and finished product stages.The p H showed a pattern of increasing,then decreasing,and then increasing,with the maximum p H after curing(6.20),the minimum after fermentation(5.51)and the p H of the final product being 5.75.TBARS values indicated a gradual increase during the rabbit processing phase.The growth rate in the roasting stage was significantly greater than that in the other processing stages,but it slightly decreased after high-temperature curing.The carbonyl content of protein oxidation did not substantially alter during the raw meat stage of each processing step,but it did after baking and heat treatment.In different processing processes,the content of essential amino acids,non-essential amino acids and total free amino acids all tended to increase and then decrease,with the post-fermentation stage being the most abundant.The freshness of the rabbit meat overall increased significantly after curing,according to a comparison of the taste activity value at each stage of processing.128 volatile flavor substances in total were found during 5 processing steps,of which 23,53,55,65,and 66 were found in raw meat,respectively,after curing,after fermentation,after roasting,and after finished product stage,showing a trend of steadily rising detections.A total of 27 substances(ROAV≥0.1)contributing to the flavor in the five processes were identified based on ROAV values,and 19 key flavor substances(ROAV≥1)in the processes were further selected for principal component analysis.The main volatile substances varied depending on the processing stages.Hexanal,1-octanol-3-alcohol,and 1-octanol-3-ketone were the three primary volatile flavoring substances found in raw meat.The volatile flavors of the cured and fermented samples were similar,and the main volatile flavors were eugenol and anisole.After roasting,3-hydroxy-2-butanone,(+)-limonene and ethyl arachidonate contributed more to its flavor.The unique flavor of fermented rabbit jerky was created by phenacetaldehyde,(E)-2-nonenal,methylcyclopentenolone,linalool,and ethyl maltol.(4)The storage experiments’ findings revealed that at all three storage temperatures,the p H of the fermented rabbit jerky tended to drop and then rise.With the extension of storage time,L* value,a* value,b* value,and sensory score progressively decreased.With longer storage times,TVB-N,TBARS,and total number of colonies increased.Pearson correlation analysis showed the highest correlation between the total number of colonies and the organoleptic score,therefore the key factor for shelf life prediction was determined to be the total number of colonies.The Arrhenius equation and first-order dynamics were used to create the shelf life predictive model.The shelf life of fermented rabbit jerky in the projected model was 98.75 d,64.53 d,and 51.24 days,respectively,with relative errors of 3.95%,0.72%,and 7.20%,respectively,all within 10%,indicating that the kinetic model can be used to predict the shelf life of fermented rabbit jerky. |
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