PVPP index

Table II. Evolution of color density (CD) and PVPP index during oak and...

Other studies have described similar results to those found in our research, that is, that ellagitannins are more abundant in French oak (26) and therefore, in wines matured in French oak barrels. So, the presence of ellagitannins enhances the color of wine and increases absorbance at 620 nm by fevoring anthocyanin-procyanidin type tannin condensations with acetaldehyde (purple pigments) and that foct also helps to explain the higher PVPP index values of wines fix)m new French oak barrels. They also prevent the development of brick-yellow color by preventing the oxidation of phenolic compounds (24). 

On the basis of these two analyses, As and Al, Glories (1978a) defined the PVPP index used to quantify the combinations occurring in the anthocyanin assay. This value increases continuously as the wine ages ... 

Time Anthocyanins (mg/1) Color intensity (OD 420 -b OD 520) PVPP index ... 

PTFE polytetrafluoroethylene PUFA polyunsaturated fatty acid PV peroxide value PVDF polyvinylidene difluoride PVP polyvinylpyrrolidone PVPP polyvinylpolypyrolidone RAS retronasal aroma stimulator RDA recommended dietary allowance RF radio frequency RFI relative fluorescence intensity RI retention index RNU relative nitrogen utilization ROESY rotational nuclear Overhauser enhancement spectroscopy RP-HPLC reversed-phase HPLC RPER relative protein efficiency ratio RS resistant starch RT retention time RVP relative vapor pressure S sieman (unit of conductance)... 

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