Research On The Ripening Characteristics Of Loquat Fruit And The Aroma Of Fermented Fruit Wine

Loquat(Eriobotrya japonica Lindl.)is an evergreen dungarunga of the rosaceae.It is a typical subtropical plant,widely cultivated in southern China.Most of the natural species distribute between 20 ° to 30 ° latitude,Ankang,Shaanxi.There is a lack of research on fruit ripening quality changes in the northern margin.The economic value of loquat fruit can be improved to the greatest extent by further processing and utilization.This article takes 'BMM','DWX','CQZS','XN2H' in Ankang,Shaanxi,as the experimental material,Five different mature periods during fruit development(green,green with yellow,yellow with green,yellow,deep yellow)were determined its sensory quality,nutritional quality,functional quality and aroma quality indicator;Artificial neural network,polynomial,attenuation exponential and Richard model were used to simulate the dynamic change law of quality in maturity process.Fruit quality was evaluated by principal component analysis.Statistical modeling,GM(1,1)grey model,Markov chain and BP artificial neural network were used to analyze the soluble sugar content and incense production law of regulatory factors(fermentation temperature,yeast variety and concentration)in the fermentation process.The microorganism population structure in different fermentation stages was identified by macrogenome technique.The main research conclusions are as follows:1.L,a,and b color parameters were used to describe fruit ripening,and there are significant differences in color parameters at different ripening stages(p<0.05).The artificial neural network model frame of 3-5-1 can better fit the fruit maturity and color parameters relationship.There are significant differences in fruit quality indexes between different ripening stages(p<0.05).One-way ANOVA was used to analyze the content of various indexes of peel and peel pulp,peel pulp is more suitable for wine making based on the comprehensive evaluation of economic value and nutritional value.There are differences in aroma types and contents between different varieties of fruits when they are ripe(p<0.10).At different stages of fruit ripening,the species and content of aroma substances have a jump stage.'XN2H' fruit aroma jump from stage ?to stage ?transition;'BMM','DWX',and 'CQZS' fruit aroma jump from stage ?to stage?.6 main component factors were extracted from 44 indexes used to evaluate fruit quality,and the eigenvalues are all greater than 1.00,which could explain the variance of 92.66 % in total.Comprehensive principal components analysis and evolution are deduced with the method of nonlinear programming method to get the maturity of the optimal solution is 3.51,namely ?mature period of 'CQZS' with good quality.The establishment of the model can reflect the dynamic changes of indicators,which has theoretical significance for quantifying the ripening mechanism of loquat fruit.2.There are increasing peak values of fructose and glucose in the fermentation process of fruit wine with different fermentation temperatures,yeast varieties and concentrations,The Gaussian model has a good fitting effect,and the mean goodness of fit is between 0.66 and 0.85,and the mean standard estimation error is between 12.61 and 19.75.The Exponential to Minimum model for reducing sugar content was adopted to better describe the decreasing rule,with an average goodness of fit of 0.80 to 0.90 and an average standard estimation error of 17.62 to 25.22.The modification of GM(1,1)gray model by Markov chain process can better reflect the randomness of fructose,glucose and reducing sugar content changes during fermentation.The structure analysis of artificial neural network model show that the response mechanism of different saccharide fermentation processes is different.Mixed fermentation technology can better control the fermentation reaction rate and fermentation material balance,regulating factor parameters as: mix yeast species,namely AC yeast,71 B yeast and EC1118 yeast by mixing ratio of 1:1:1,yeast dosage of 0.55 g/L,fermentation temperature of 22 ° C,the product is 12.5% alc.Mix yeast fermentation is conducive to the production of alcohol substances and aroma enrichment,while non-yeast fermentation is conducive to the production of esters.The higher yeast content is,the better alcohol content is,and the lower yeast content is,the better ester content is.Low fermentation temperature is conducive to the enrichment of alcohol substances;high fermentation temperature is conducive to the production of ester substances.There is a significant difference in the proportion of aroma substances in different types of loquat fruits and wine(p<0.01).The proportions of aroma substances in 4 species are mainly aldehydes,with an average percentage value of 85.10 %.The content of aroma substances in fruit wine are mainly alcohols and esters,with an average percentage value of 39.37 % and 20.94 %,respectively.The main flavoring substances of loquat fruit and wine are different,and the aroma types are different.In this study,the changes of soluble sugar and aroma in the fermentation process of different regulatory factors were thoroughly analyzed,so as to optimize the fermentation process.3.Dominant fungi in natural fermentation,non-sterilization plus yeast and sterilization plus yeast are Saccharomyces cerevisiae in the early stage of fruit wine fermentation.With fermentation progressing,the abundance of Saccharomyces cerevisiae increased from 0.4% to 3.8%,9.30% to 10.30% and 15.2% to 18.1%,respectively.Saccharomyces cerevisiae has effect on ester and alcohol with percentage of 86 %,and 70 % of acid production was related to Saccharomyces cerevisiae.Acinetobacter johnsonii is the main bacterium affecting the production of acid substances throughout the fermentation process,and its influence on volatile substances is similar to that of Saccharomyces cerevisiae.This study reveals the effect of microorganisms in fermentation broth on aroma components,and provided a theoretical basis for optimizing aroma of fruit wine.