Study On The Antioxidant Activity And Methods Of Detection In Wine

Epidemiological evidence indicates that the moderate consumption of wines reduces theincident of coronary heart disease,artherosclerosis,platelet aggregation and Cancer.Thisgreater protection may be due to the phenolic components of wines,which are particularlyabundant in the red wine,since they behave as reactive oxygene species scavengers and metalchelators.The wine industry is growing and the wine market has a wider space to develop inChina,it will be even more prosperous in future.To date,there has been no publishedresearch on the chemical quality and antioxidant activity of wines produced in China.Withestablishing an"antioxidant profile"this paper will help to better understand the quality ofcurrent wines and stimulate the development of enological techniques for their enrichment.Because multiple reaction characteristics and mechanisms are usually involved,no singleassay will accurately reflect all antioxidants in a mixed or complex system.Thus,to fullyelucidate a full profile of antioxidant capacity,different antioxidant capacity assays may beneeded.The purpose of the study was to develop a simple,accurate and rapid antioxidantcapacity analysis method for measuring antioxidant capacity in table wine.The developedmethod could have the application in routine quantific ation of antioxidant capacity forChinese table wine.The parameters of the CUPRAC (cupric reducing antioxidant capacity)method were optimized.It involves mixing the wine with solutions of 5mM CuCl₂,3.75 mMneocuproine,and ammonium acetate at pH 7,and measuring the absorbance at 450 nm after30 min.Optimum dilutions for white and red wines were set up as a function of their totalphenolic content (for spectrophotometric measurements,red wine,dilution 12.5 to 25,whitewine,dilution 1.25 to 5;for microplate reader,red wine,dilution 62.5 to 125,white wine,dilution 6.25 to 25).The parameters of the ORAC (oxygen radical absorbance capacity)method were optimized.It involves mixing the wine with solutions of 4×10^-3μM sodiumfluorescein,160 mM AAPH,and phosphate buffer at pH 7.4.Optimum dilutions for whiteand red wines were set up as a function of their total phenolic content (red wine,dilution 500to 1000;white wine,dilution 200 to 500).The antioxidant activity of wines was measured by different analytical methods:oxygen radical absorbance capacity (ORAC),reducing power (CUPRAC),2,2-azino-di-(3-ethylbenzothialozine-sulphonic acid) (ABTS),2,2-diphenyl-1-picrylhydrazyl(DPPH),hydroxyl radical scavenger activity (HRSA),superoxide radical scavenger activity(SRSA),lipid peroxidation (TBARS) and chelating capacity (MC).As expected,the redwines had much higher antioxidant capacity than ros(?) wines and white wines.In order tocompare antioxidant capacity of different grape variety,we chose several wines.These wineshad same situations including same age,vintage and winemaking techniques.Amongst the redwines,Cabernet Sauvignon represented the wine with the highest antioxidant capacity.Amongst the white wines,Italian Riesling represented the one with lowest antioxidantcapacity.Total phenols,total flavonoids,total flavanols and total anthocyanins of wines weredetermined.As expected,the red wines had much higher phenolic content than ros(?) wines andwhite wines.The phenolic content of three red wines (Cabernet Sauvignon,CabernetGernischet and Merlot) and three white wines (Chardonnay,Italian Riesling and Riesling)were analyzed and compared.Amongst the red wines,the total phenols,the total flavonoidsand the total flavanols decrease in the order:Cabernet Sauvignon＞Merlot＞CabernetGernischet,while the total anthocyanins decrease in the order:Cabernet Gernischet＞Cabernet Sauvignon＞Merlot.Amongst the white wines,Chardonnay and Italian Riesling,respectively,represented the wine with the highest and lowest phenolic contents.The totalphenol,flavonoids and flavanol contents of wines exhibited the strongest correlation withantioxidant properties,while total anthocyanins exhibited weaker correlations.This work analyzed the relativity about the most common nine methods that can measureantioxidant activity by studying many literatures.At the time,the result of wine antioxidantactivity in this paper was analyzed.Regarding different methods,the significant correlationbetween two methods was confirmed with seven methods (TP,ORAC,ABTS,DPPH,CUPRAC,SRSA and HRSA),while TBARS and MC exhibited weaker correlations withother methods.Taken together,a relatively tight coupling of these four parameters (ORAC,DPPH,ABTS and CUPRAC) indicates that every one of them can be considered as a relevantand reliable characteristic of the antioxidant capacity of wines.And also,there is muchchange of relativity in different methods for different materials.So,at the present time,weshould choose several methods which have highest relativity with physiology,and choose themethods which based on other mechanism at the same time.The total phenolic content and antioxidant activity of grape seed powder extracted by invitro procedure.It has been found that grape seed powder has higher total phenolic contentand antioxidant capacity.As for solvents extracts,extraction with acetone:water (70:30) led to maximum phenol content and antioxidant capacity,while water gave the lowest phenolcontent and antioxidant capacity.The in vitro digestion method is simple,cheap,and reproducible and can be used tostudy a wide range of experimental conditions.Therefore,the biological properties ofantioxidants may depend on their release from the food matrix during the digestion processand may be more useful for nutritional purposes than the values determined in chemicalprocedure.It has been found that both wine and grape seed powder have higher total phenoliccontent and antioxidant capacity by in vitro physiological procedure.As for digestiveenzymatic extracts,total phenolic content and antioxidant capacity of the dialysates of wineand grape seed powder were lower than those of the retentates (3:7-1:1).