The impact of prefermentative addition of five single-enzyme activities(pectin lyase,polygalacturonase,pectin methyl esterase,xylanase,and arabinase)on the phenolic content,colour characteristics,and volatile composit...The impact of prefermentative addition of five single-enzyme activities(pectin lyase,polygalacturonase,pectin methyl esterase,xylanase,and arabinase)on the phenolic content,colour characteristics,and volatile composition of grape musts resulting from pellicular maceration of Chardonnay,Arneis,Greco,and Falanghina white varieties was studied with the aim of enhancing aroma composition without negatively affecting colour perception.In addition,standard physicochemical parameters were determined.Pectin lyase,polygalacturonase,and arabinase enzymes reduced the must browning,when compared with untreated control,as reported by lower total polyphenol index,absorbance at 420 nm,and a^(*) colour coordinate for all varieties tested.Regarding the volatile composition determined by solid-phase extraction and GC-MS analysis,variety effect was observed for the enzyme treatments studied.The concentration of free vanillin decreased significantly in these last three varieties using polygalacturonase and arabinase treatments whereas 4-vinylguaiacol increased in pectin lyase-treated samples.Free terpene compounds,such as furan linalool oxide,increased in Chardonnay and Falanghina varieties using polygalacturonase,xylanase,and arabinase for the second variety whereas pectin lyase for the first one.Contrarily,glycosylated terpenes,such us(Z)-8-hydroxylinalool,decreased when using pectin lyase and xylanase for Arneis;however,it also occurred for Falanghina using polygalacturonase treatment.The xylanase activity influenced mostly the volatile composition of the Arneis variety whereas arabinase did for Greco and Falanghina.The differences between enzyme-treated grape musts and control samples were less evident on the Chardonnay variety.Therefore,enzyme activity can affect the volatile composition of grape must differently depending on the target variety.展开更多
Wine authentication through grapevine DNA traceability could be affected by wine technological processing treatments.In this study,filtration treatments including depth filter treatment using kieselguhr,perlite and me...Wine authentication through grapevine DNA traceability could be affected by wine technological processing treatments.In this study,filtration treatments including depth filter treatment using kieselguhr,perlite and membrane filtration using different types and pore sizes(0.22 and 0.45μm)were applied on‘Nebbiolo’wine at an experimental scale.We used‘Nebbiolo’because it is an important Italian winegrape variety used to produce high-quality wines.Phenolic composition and color properties of the treated wines were examined using spectrophotometric and HPLC methods,while grapevine DNA traceability was evaluated using PCR based assays.The filtration treatments,as expected,significantly decreased turbidity compared to the unfiltered control,although total phenolics,total flavonoids and total non-flavonoids were not significantly affected.A significant reduction of acetylated anthocyanins by 6.1%-43.3%was observed in filtered wines,which could account for the reduced in total anthocyanins and color intensity of these wines.Grapevine DNA was significantly reduced in filtered wine by 37.2%-99.7%,with the reduction rate depending mainly on the properties of filter material.Polyvinylidene difluoride(PVDF)membranes with a pore size of 0.22μm showed highest reduction of grapevine DNA in wine,resulting in the failure of TaqMan®single nucleotide polymorphisms(SNPs)-based assays used to detect grape DNA in wines.展开更多
文摘The impact of prefermentative addition of five single-enzyme activities(pectin lyase,polygalacturonase,pectin methyl esterase,xylanase,and arabinase)on the phenolic content,colour characteristics,and volatile composition of grape musts resulting from pellicular maceration of Chardonnay,Arneis,Greco,and Falanghina white varieties was studied with the aim of enhancing aroma composition without negatively affecting colour perception.In addition,standard physicochemical parameters were determined.Pectin lyase,polygalacturonase,and arabinase enzymes reduced the must browning,when compared with untreated control,as reported by lower total polyphenol index,absorbance at 420 nm,and a^(*) colour coordinate for all varieties tested.Regarding the volatile composition determined by solid-phase extraction and GC-MS analysis,variety effect was observed for the enzyme treatments studied.The concentration of free vanillin decreased significantly in these last three varieties using polygalacturonase and arabinase treatments whereas 4-vinylguaiacol increased in pectin lyase-treated samples.Free terpene compounds,such as furan linalool oxide,increased in Chardonnay and Falanghina varieties using polygalacturonase,xylanase,and arabinase for the second variety whereas pectin lyase for the first one.Contrarily,glycosylated terpenes,such us(Z)-8-hydroxylinalool,decreased when using pectin lyase and xylanase for Arneis;however,it also occurred for Falanghina using polygalacturonase treatment.The xylanase activity influenced mostly the volatile composition of the Arneis variety whereas arabinase did for Greco and Falanghina.The differences between enzyme-treated grape musts and control samples were less evident on the Chardonnay variety.Therefore,enzyme activity can affect the volatile composition of grape must differently depending on the target variety.
基金financial support of Shandong Provincial Education System Government Sponsored Study Abroad Program.
文摘Wine authentication through grapevine DNA traceability could be affected by wine technological processing treatments.In this study,filtration treatments including depth filter treatment using kieselguhr,perlite and membrane filtration using different types and pore sizes(0.22 and 0.45μm)were applied on‘Nebbiolo’wine at an experimental scale.We used‘Nebbiolo’because it is an important Italian winegrape variety used to produce high-quality wines.Phenolic composition and color properties of the treated wines were examined using spectrophotometric and HPLC methods,while grapevine DNA traceability was evaluated using PCR based assays.The filtration treatments,as expected,significantly decreased turbidity compared to the unfiltered control,although total phenolics,total flavonoids and total non-flavonoids were not significantly affected.A significant reduction of acetylated anthocyanins by 6.1%-43.3%was observed in filtered wines,which could account for the reduced in total anthocyanins and color intensity of these wines.Grapevine DNA was significantly reduced in filtered wine by 37.2%-99.7%,with the reduction rate depending mainly on the properties of filter material.Polyvinylidene difluoride(PVDF)membranes with a pore size of 0.22μm showed highest reduction of grapevine DNA in wine,resulting in the failure of TaqMan®single nucleotide polymorphisms(SNPs)-based assays used to detect grape DNA in wines.
