Study On The Technology Optimization And Quality Changes During Processing And Storage Of Fermented Sausage

Fermented sausage is one of the most produced products in fermented meat products,which has the advantages of unique flavor,high nutritional value,good meat quality,easy digestion and absorption,etc.It is loved by people all over the world and has a high potential market value.In recent years,a lot of research has been conducted at home and abroad on fermented sausages and starter cultures,and starter cultures have been used to produce and develop fermented sausages to increase their added value.However,there are still problems such as single product type,unbalanced quality,overly acidic taste,long production cycle and high fat and salt content in fermented sausages,thus,its commercialization and economic benefits are low.At the same time,fermented sausages are susceptible to factors such as temperature and microorganisms during production,processing,market circulation and storage,resulting in decreased quality and shortened shelf life,which in turn leaded to a reduction in their economic value.Therefore,it is necessary to conduct an in-depth study on the quality evolution of fermented sausages during processing and storage.Based on the above background,in order to increase the variety of fermented sausages,improve the taste and texture of sausages,enrich the flavor of sausages,enhance the quality of sausages,and meet consumers’ dietary needs of health,nutrition and safety,this current study took fermented sausages as the research object,and deeply explored the influence of different commercial starter cultures on the quality of fermented sausages,and optimized their fermentation process,as well as explored the changes of physical and chemical quality,processing quality and eating quality in the process of processing.Finally,the quality changes of fermented sausages during storage were studied and a shelf-life prediction model was established.It is proposed to develop a fermented sausage with high nutritional value,unique flavor,short fermentation cycle and high safety,so as to provide theoretical basis and technical guidance for developing new types of fermented sausages,improving the quality of sausages,regulating the edible quality of sausages during processing,improving the storage characteristics of products and selecting storage methods.The main research contents and conclusions are as follows:(1)To investigate the effects of four commercial starter cultures,SM-181(containing Lactobacillus sakei,Staphylococcus xylosus),LHP+CS-300(containing Pediococcus pentosaceus,Pediococcus lactis,Staphylococcus carnosus),ECLC-719(containing Debaryomyces Hansenii,Lactobacillus curvatus,Staphylococcus carnosus,Staphylococcus vitulinus)and BFFI-712(containing Lactobacillus sakei,Staphylococcus carnosus and Staphylococcus carnosus subsp)on the quality characteristics of fermented sausages and conduct a comprehensive evaluation.The results showed that compared with the control check group,the addition of starter cultures had no significant impact on the moisture content of sausage(P>0.05),but it could reduce the p H and nitrite content of sausage,inhibit the oxidation of lipids and proteins,and also promote the color development of sausages,improve the texture of sausages,promote the enrichment of taste and flavor substances,and enhance the comprehensive sensory score of sausages.Further,correlation analysis,factor analysis and cluster analysis revealed that when SM-181 was used as a starter culture for fermentation,the comprehensive quality of fermented sausage was the best,and it was the most suitable starter for fermented sausage production among the four commercial starter types,which could be used for the optimization of subsequent fermentation processes.(2)The response surface method was used to optimize the fermentation process parameters of fermented sausage.The single-factor experiment found that the fermentation time,fermentation temperature and addition amount of starter had a significant impact on the p H,comprehensive sensory score,color difference and texture of sausages.After determining the optimization range of each factor,the optimal fermentation parameters for fermented sausages were obtained by response surface tests: fermentation time 51.460 h,fermentation temperature 25.219℃,and addition amount of starter 0.025%.The predicted value of the comprehensive sensory score was 9.136,and the validated value was 9.107,with a coincidence rate of 99.68% with the predicted value.Finally,the fermentation parameters for sausage were determined as follows: fermentation time 51 h,fermentation temperature 25°C,and addition amount of starter 0.025%.The sausages made under this condition were firm and elastic,with rich flavor and good color,which indicated that the final determined process was feasible.(3)Exploring the changes in the quality characteristics of fermented sausages at different processing stages,it was found that as the processing process progressed,the moisture content of sausage gradually decreased from 60.78% to 21.79%,p H decreased from 6.12 to 5.06,TBARS and carbonyl content gradually increased,while sulfhydryl showed an opposite trend.The color of fermented sausages gradually deepened,the texture hardened and the chewiness increased.A total of 17 free amino acids were detected during the entire processing process,and the total free amino acid content in sausages gradually increased as the processing progressed.The flavor of fermented sausage processing was evaluated by gas chromatography-mass spectrometry,and it was found that a total of 159 volatile flavor substances,mainly aldehydes,alcohols,esters,ketones and hydrocarbon compounds,were detected in the sausage throughout the processing.The relative odor activity analysis of the volatile components in the six processing stages revealed that there were 58 volatile flavor substances contributing to the sausage processing,mainly aldehydes,alcohols,esters and olefins.Finally,the principal component analysis of flavor found that the cumulative contribution of the variance of the four principal components reached 99.815%,which can better explain the changes of volatile flavor substances of sausage during processing.(4)To investigate the changes in the quality of fermented sausages during storage at 4℃,25℃ and 35℃,and establish a shelf-life prediction model.The results showed that with the extension of storage time,the moisture content of sausage gradually decreased,the p H first decreased and then increased,the L* and a* values first increased and then leveled off and slightly decreased,and the b* values changed irregularly.TBARS,TVB-N and the total viable count(TVC)gradually increased with the prolongation of storage time,and the TVC exceeded the national safety standard when stored at 35℃ for 15 days.The total number of lactic acid bacteria increased and then decreased during the storage period,and no coliforms were detected throughout the storage process.The sensory score of sausages at 35℃ first increased and then decreased,while the sensory score gradually decreased at 4℃ and 25℃.Through correlation analysis,TVB-N and TVC were determined as the key indicators of the sausage shelf life prediction model.The linear regression method was used to determine the reaction model as a first order kinetic model,and the TVC with a faster rate of change was used as the shelf life prediction index.The Arrhenius equation was established to predict the predicted shelf life of fermented sausage at 4℃,20℃,and 30℃ as 79.28 d,32.88 d,and19.89 d,respectively.The relative errors with the actual validated values were 0.90%,6.05%and 0.56%,respectively,indicating that the model is reliable and provides a theoretical basis for quality control and shelf-life prediction of other fermented meat products.