The protective effect of cyclodextrin on the color quality and stability of Cabernet Sauvignon red wine

The impact of cyclodextrins(CDs)on wine quality and stability remains largely unknown.This study systematically assessed the protective effect of the post-fermentation addition of CDs on color stability of red wine from the viewpoints of color characteristics,copigmentation and phenolic profiles.The grey relational analysis(GRA)and principal component analysis(PCA)methods were employed to dissect the key effective determinants related to color quality.The addition of CDs induced a significant hyperchromic effect of 8.19-25.40%,a significant bathochromic effect and an enhancement of the color intensity.Furthermore,the evolution of anthocyanin forms and the content of monomeric anthocyanins revealed that β-CD is a superior favorable cofactor during wine aging,but for long-term aging,2-HP-β-CD and 2-HP-γ-CD are more beneficial in promoting the formation of polymerized anthocyanins and color stability.This work provides an important reference for the use of CDs to enhance the color quality and stability of red wines.

Flavonoid extracts from chrysanthemum with appropriate anthocyanins turn blue when exposed to iron ions

Although some species that accumulate only cyanidin(Cy)in nature can produce blue flowers through iron ions,there has been no evidence of blue chrysanthemums being generated in this manner.This study revealed that flavonoid extracts from the ray florets of the chrysanthemum cultivar‘Wandai Fengguang’turned blue when exposed to Fe^(3+).Samples that could turn blue were labeled as CB(Cy-determined blue flowers),while samples that did not turn blue were labeled as CN(Cy-determined non-blue flowers).After a series of experiments,a stable screening system was established using flavonoid extracts containing NaAc buffer at pH 5.5 and a total anthocyanin concentration(TAC)of 30 μmol·L^(-1),and the addition of Fe^(3+)from 0 to 0.25 μmol·L^(-1)allowed for the selection of five CB samples from 39 chrysanthemum cultivars.All five CB samples exhibited flower color phenotypes that belonged to Cluster-I with redness(a*)values ranging from 29.03 to 45.99,yellowness(b*)values from-11.31 to 3.77,and brightness(L*)values from 29.07 to 45.99.Additionally,the ratio of TAC to total luteolin concentration(TLC)was found to be a critical factor for distinguishing between CB and CN samples.To realize the desired blue hue in the flavonoid extracts with the participation of Fe^(3+),a TAC to TLC ratio of 2.25 and above is required.Moreover,the protoplasts and ray florets of CB samples that turned blue with the involvement of Fe^(2+)showed great potential for cultivating blue chrysanthemums through ferric-anthocyanin chelate.Overall,this study reveals that blue flowers can be cultivated through the increase in the iron ion concentration,combined with the accumulation of Cy.

Impact of rutin and buckwheat(Fagopyrum esculentum)extract applications on the volatile and phenolic composition of wine

The aim of this research is to study the possibility of increasing the quality of red wins made with the Monastrell grape variety.A methodology was established to improve the concentration levels of polyphenol and aroma in these wines.Among flavonoids,the copigmenting effect of rutin stands out,and was tested in both winery and field applications.Buckwheat extract(Fagopyrum esculentum),in which rutin is the main flavonoid,may be of interest for viticulture given its biological activity.This paper focuses on researching the effect of applying the prefermentative vegetable extract of buckwheat(Fagopyrum esculentum)on the concentration of polyphenols and aroma compounds in vineyards.Simultaneously,a study was carried out to compare the effect of pure copigment(rutin)when applied in vineyards and cellars.Traditional vinification was done,plus prefermentative cold maceration.The application of buckwheat extract,and rutin extract to a lesser extent,to Monastrell grapes increased the concentration of malvidin and other anthocyanins,and total anthocyanins.After 12-month storage,no differences were observed in the percentage of copigmented,polymerised and free anthocyanin,the total polyphenol concentration,and the tannin quality parameters like DMACH(aldehyde p-dimethylaminoacimaldehyde)and the Gelatin Index.The concentrations of diethyl succinate,2 phenylethyl acetate,vanillin and ethyl octanoate increased,while other compounds decreased when the copigment was added.The maceration technique followed during the vinification process had very little effect on polyphenolic compounds.The prefermentative maceration slightly increasing the concentration of total polyphenols,but had no effect on the parameters related to colour,anthocyanin concentration,nature of anthocyanins,their binding state or tannin quality parameters.The results showed that cold prefermentation maceration increased the concentration of some volatile compounds,including alcohols and esters,which should be considered important contributors to Monastrell wine aroma.The combination of the applying buckwheat extract and pure rutin together,and prefermentative cold maceration,positively affects the polyphenolic concentration and increases the concentration of quality volatile compounds.