Pasteurization is a thermal process in which heating of liquid food at particular time and
successive cooling is performed with the intention of killing pathogens and deactivating
enzymes. Grape juice pasteurization even kills the most resistant mold which is detrimental
for the production of quality wine (Pederson, 1936).

This research paper concentrated on studies on the effect of pretreatments on the quality of
grape wine. The changes due to pretreatments on the functional properties such as total
phenols, tannins and catechins. Hence, various thermal treatments such as microwave with
a combination of 300 W for 2, 4 and 6 min and conventional thermal pasteurization at 50, 60,
70 C with the time interval of 30 and 60s were applied to the grape must to study the
extraction efficiency of polyphenols.