Grape Mash Treatment TSS (ºBrix) TA1 (%) TSS/TA ratio Instrumental Colour Total anthocyanin concentration2 (mg M3GE/L) FRAP3
(g TE/L)
L* a* b*
Control4 16.1c 0.60c 26.6 42.3a 24.4bc 25.6a 9.1d 0.15c
65 °C-15 min 17.1b 0.68bc 25.5 28.6b     33.0a 18.5b 28.4c 0.30c
65 °C-30 min 17.5b 0.74b 23.7 23.7c 29.2ab 12.4c 57.5b 1.62b
85 °C-15 min 17.5b 0.79ab 22.4 23.5c 27.8ab 11.7c 67.2b 1.66b
85 °C-30 min 18.9a 0.89a 21.7 21.4c     20.8c 6.3d 235.6a 4.05a
P-value5 0.0001 0.0023 0.0668 0.0001 0.0059 0.0001 0.0001 0.0001
TSS, Total soluble solids
1TA, Percentage titratable acidity (g tartaric acid equivalence/100 mL)
2Total anthocyanin content measured using pH differential method (M3GE, malvidin-3-O-glucoside equivalence)
3FRAP, Ferric reducing capacity of plasma, g TE/L, g Trolox equivalence per L
4Control consisted of juice obtained by pressing grapes without subjecting to the heat treatment of grape mash
5Means (n=3) followed by different letters (a-d) within the same column represent significant differences according to Duncan’s Multiple Range test (p<0.05)
Table 1: The effect of heat treatment of grape mash on physicochemical parameters of the recovered juice.