查看更多>>摘要：Yellow rice wine(Huangjiu)is a traditional alcoholic beverage in China.This study aimed to find a new method to reduce the acidity of Huangjiu.Three membranes with different molecular weight cut-offs(200,1000,and 2000 Da)were selected to separate small molecules in Huangjiu,and then the adsorption of four models of weakly basic anion-exchange resins(335,D301,D314,and D354)on the organic acids in the filtered fractions of Huangjiu was investigated.The D354 resin exhibited the highest adsorption rate of 157.74 mg/g and the adsorption of acids was more consistent with the proposed second-order kinetic model.The adsorption capacity of D354 resin decreased with increasing temperature,and the adsorption of D354 resin correlated better with the Freundlich isotherm model.The initial deacidification efficiency of the D354 resin was 91.52％and it decreased by 3.88％after 10 regenerations.After the D354 resin treatment,the total acid content decreased by 56.11％,and the retention rates of amino acids and volatile substances reached 97.96％and 81.93％,respectively.The results showed that D354 resin could be used for the deacidification of Huangjiu.Membrane separation combined with resin adsorption process provides a new method to reduce the acidity of Huangjiu,which helps to maintain the flavor of the deacidified Huangjiu while efficiently reducing the acidity.
查看更多>>摘要：Objectives:Osmanthus black tea(OBT)is produced by reprocessing black tea while it absorbs the fragrance of Osmanthus fragrans and this scenting process is crucial for forming the unique aroma of OBT.This work intended to reveal the effects of scenting parameters,the types of base tea,and scenting technologies on the aroma quality of OBT.Materials and Methods:In this study,volatile compounds of OBTs with different scenting parameters,types of base tea,and scenting tech-nologies were analyzed by solid-phase microextraction and gas chromatography-mass spectrometry.Weighted gene co-expression network analysis and orthogonal partial least squares discriminant analysis were used to identify the key volatile compounds of OBT.Results:More than 80 volatile compounds of OBT were found,and six compounds,α-ionone,β-ionone,γ-decalactone,dihydro-β-ionone,dihydro-β-ionol,and 6-pentyl-2-pyrone,were identified as the key volatiles of OBT.As scenting time(ST)increased,the key volatile compounds in OBT showed an upward trend or increased initially and then decreased.Meanwhile,the contents of key volatile compounds increased as the ratio of flowers to tea(RFT)increased.In addition,base teas with a high proportion of pekoes produced higher-quality OBT by absorbing more key volatile compounds from O.fragrans.Comparing OBTs made from the fast-scenting process and the traditional scenting process(TS),showed that higher aroma quality was obtained through repeated scenting rounds of TS.Conclusions:Appropriate long ST and high RFT,as well as base tea with a high proportion of pekoes andTS with repeated scenting rounds are beneficial for the accumulation of odorants and the improvement of aroma quality in OBT.
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