Study On The Influence Of Fermentation Technology Of Navel Orange Wine On Characteristic Flavor Formation

Xinning Langfeng navel orange is one of the four largest navel oranges in China.The fruit has a strong flavor and tastes sweet and sour.The development of navel orange fermented wine can not only increase the added value of product s,extend the industrial chain,but also drive the increase of local farmers' income and achieve rural revitalization,so it has a broad development prospect.However,navel orange wine processing is faced with such bottleneck problems as heavy "post-bitter taste" and weak product aroma,which seriously affects the quality of navel orange wine and restricts the rapid development of the industry.Langfeng navel orange was used as raw material in this study,and different active dry yeasts were used to ferment navel orange juice.The quality of fruit wine was evaluated comprehensively and the most suitable yeasts were selected.Navel orange juice was fermented with fine yeast at different temperatures,and the change of flavor of navel orange wine was investigated to determine the best fermentation temperature.The effects of supplemental nitrogen source DAP on the fermentation performance,flavor and quality of navel orange wine were further studied by adding different concentrations of supplemental nitrogen source DAP into navel orange juice.The research results are as follows:1.The physicochemical indexes,contents of limonin and omirin and aroma substances of navel orange wine fermented by 6 active dry yeast DV10,L2323,K1,RV002,RV171 and BV818 under the sa me fermentation process were compared,and the most suitable yeast for navel orange wine fermentation was determined by principal component analysis.The results showed that RV002 had the highest alcohol content,RV171,RV002,DV10 and K1 had the lower cont ents of limonin and nomirin,and the "post-bitter taste" of navel orange wine was lighter.The OAV values of ethyl octanoate,phenyl ethyl acetate,ethyl acetate,nonal and acetaldehyde in DV10 were the highest,and the wine had the strongest aroma.The qual ity of navel orange wine was comprehensively evaluated by quality index and sensory score,and the results showed that DV10 was the most suitable yeast for navel orange wine production.2.DV10 was used to ferment navel orange wine at 15 ?,18 ?,21 ?,24 ? and27 ? to explore the variation of flavor of navel orange wine fermentation with temperature.The results showed that the appropriate fermentation temperature could significantly improve the overall aroma of navel orange wine,and thus improve the flavor of navel orange wine.Terpinyl acetate only in 21 ? navel orange wine fermentation temperature detection,give the navel orange aromas of lemon and lavender fragrance,and isoamyl alcohol,benzyl alcohol,isoamyl acetate,palmitic acid ethyl ester,15 acid ethyl ester,decanoic acid,nonyl aldehyde,ketone of beta"Damascus and D-limonene characteristics such as aroma in 21 ? the highest content of navel orange wine,full-bodied fragrance of flowers and fruit.Sensory analysis of aroma showed that navel o range wine fermented at 21 ? had the strongest floral,fruity and herbal fragrance,the highest overall aroma score,the most complex aroma level and the best flavor.3.DAP with mass concentrations of 0 mg/L,120 mg/L,240 mg/L and 360 mg/L were added into navel orange juice,respectively,and navel orange wine was fermented by yeast DV10 at 21 ?.The results showed that DAP increased the fermentation rate of navel orange wine and shortened the main fermentation time by 2 d to 3 d.With the increase of DAP concentration,alcohol content and total acid gradually increased,while limonin and nomirin showed a trend of first decreasing and then increasing.DAP increased the total amount of free amino acids and essential amino acids in navel orange wine,and the content of free amino acids in navel orange wine supplemented with 120 mg/L DAP was the highest.DAP changed the aroma composition of navel orange wine,decreased the accumulation of higher alcohols,and promoted the release of esters,aldehydes and ketones,phenols and other substances.Ethyl heptanate,octyl acetate,nonyl acetate,amyl caprylate and iso-amyl acetate were detected only in navel orange wine with DAP of 120 mg/L,and the contents of ethyl caprylate,caprylic acid,2,4-dit-butyl phenol,nonal,?-dammasone and D-limonene with floral and fruit aroma were also the highest in navel orange wine with DAP of 120 mg/L.The correlation between characteristic aroma OAV value and amino acid content of navel orange wine showed that the increase of amino acid content in navel orange wine could promote the formation of some characteristic aroma substances such as esters,phenols,aldehydes and ketones,which gave navel orange wine its unique flavor.The comprehensive evaluation results showed that the quality of navel orange wine fermented with DAP concentration of 120 mg/L was the best,with mellow and soft body,unique flavor and strong typicality.