| Acerola cherry,also known as West Indian cherry,is native to tropical America and is now cultivated on a large scale in Hainan.The production of Acerola cherry wine is a good way for the further processing of Acerola cherries,which could not only alleviate the problem of perishability and short storage life of Acerola cherries,but also create good economic and social benefits,laying a foundation for the creation of Hainan specialty products.However,due to the absence of specific high-effective strains for producing acerola cherry wine,the prominence and typicality of the fruit flavor of Acerola cherry wine are not outstanding.Additionally,the lack of the mature fermentation system for Acerola cherries also makes it difficult to improve the quality and value of Acerola cherry wine.Therefore,this study will focus on the selection of Saccharomyces cerevisiae and the optimization of fermentation conditions;selecting the special yeast strains for Acerola cherry wine during the selection of the separated yeast strains and using the special yeast strains to produce Acerola cherry fruit wine and yellow wine.The fermentation conditions were optimized in the research to achieve the purpose of producing high-quality Acerola cherry wine with excellent strains and optimized fermentation conditions.This research could provide the theoretical basis and reference for the industrialized and standardized production and technology of high-quality Acerola cherry wine and create a new path for acerola cherry deep processing industry in Hainan.The main results are as follows:(1)In order to screen out the best yeast strains suitable for the fermentation characteristics of Acerola cherry wine,113 strains of yeast were screened out in this experiment from the Acerola cherry fruit epidermis,natural fermentation broth,Acerola cherry flowers and Acerola cherry leaves from the Acerola cherry planting base in Ding' an county,Hainan province.Through the observation of yeast morphology,tolerance test,physiological and biochemical identification test,2 strains of yeast with excellent fermentation performance were selected,which were strains FP-7 and FP-8.Both strains can produce gas 12 hours after the start from the fermentation,and the gas production reached the full tubule of Durham's fermentation tube.The fermentation wine precision was more than 10%vol,and both were able to tolerate ethanol concentration of 15%vol and SO2 concentration of 250mg/L.The results of physiological and biochemical identification of the two strains were consistent with that of Saccharomyces cerevisiae in the strain identification manual.The strains FP-7 and FP-8 were identified as Saccharomyces cerevisiae by the sequence identification of 26Sr DNA D1/D2 and phylogenetic tree analysis.(2)Fermentation test of Acerola cherry fruit wine was carried out by using the selected saccharomyces cerevisiae FP-7,FP-8 and Anqi Saccharomyces cerevisiae respectively.The yeast growth curve,the alcohol content of Acerola cherry fruit wine,the amount of residual sugar,and the sensory evaluation score were analyzed in the test.The results show that the Saccharomyces cerevisiae FP-8 have shorter fermentation time,faster fermentation speed,higher alcohol production.The acerola cherry fruit wine fermented by Saccharomyces cerevisiae FP-8 is fruity and full-bodied,with the mellow and refreshing taste,and strong typicality.The aroma components of Acerola cherry fruit wine brewed by strains FP-7 and FP-8 were analyzed,A total of 45 kinds of aroma components were detected in the FP-8 fermented acerola cherry wine,including 13 kinds of alcohols and 20 kinds of esters.A total of 35 kinds of aroma components were detected by FP-7 fermented acerola cherry wine.There are 5 kinds of substances and 19 kinds of esters.The amber aroma of FP-8 fermented cherry fruit wine is more abundant.Among the alcohols in Acerola cherry fruit wine fermented by strains FP-7 and FP-8,the relative content of ethanol and phenylethyl alcohol were high and were the main components of alcohols in the Acerola cherry fruit wine.The ethanol content in Acerola cherry fruit wine fermented by strains FP-8 was higher than that in Acerola cherry fruit wine fermented by strains FP-7.Among the esters in Acerola cherry fruit wine fermented by strains FP-7 and FP-8,there are following main esters with relatively high contents:hexadecanoic acid,ethyl ester;dodecanoic acid,ethyl ester;decanoic acid,ethyl ester;hexanoic acid,ethyl ester;tetradecanoic acid,ethyl ester;octanoic acid,ethyl ester;benzoic acid,ethyl ester,and phenethyl acetate.1-Butanol,3-methyl-,formate was only found in fruit wine FP-7 and is high in content.1-Butanol,3-methyl-,acetate was only found in fruit wine FP-8 with high content.After comprehensive comparison,the Saccharomyces cerevisiae FP-8 was chosen for produce acerola cherry fruit wine.(3)Using FP-8 Sacchai-omyces cerevisiae to ferment Acerola cherry fruit wine and optimizing Acerola cherry fruit wine fermentation process conditions through single factor experiments and Box-Behnken response surface method.The results show that the optimal Acerola cherry fruit wine primary fermentation condition is as follows:the inoculation concentration 3.4%,initial sugar content 28.2%,fermentation temperature 25?,SO2 addition amount 100 mg/L,fermentation time 7 d.Under these conditions,the Acerola cherry fruit wine was brewed with harmonious components with clear,transparent and shiny outlook,and highlighting the flavor of the Acerola cherry fruit wine.The alcohol content of the product was 13.9%vol,and the sensory evaluation score was 95.(4)Using Acerola cherry and japonica rice as raw materials fermented Acerola cherry yellow rice wine with rice leaven and Saccharomyces cerevisiae FP-8.Based on single factor experiments,optimizing the fermentation process of Acerola yellow rice wine by Box-Behnken response surface method.The results showed that,after saccharification,the best fermentation process parameters are as follows:Saccharomyces cerevisiae addition amount 0.8%,liquid-to-solid ratio L1:1,Acerola cherry fruit pulp addition amount 33%,fermentation temperature 26?,fermentation time 4 d.Under the optimal brewing conditions,the Acerola cherry yellow rice wine was produced with a transparent clear orange color,strong characteristic aroma,and mellow soft taste.The alcohol content of the product was 13.8%vol and the sensory evaluation score was 96.4. |
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