摘要：Foça Karası (Izmir-Turkey) variety red grapes are used as raw material and grape mash subjected to ohmic heating, microwave heating and conventional thermal treatment before pressing and pressed. Then grape juice samples were pasteurized at 90 °C for 1.5 minutes. After production of red grape juices; effects of ohmic heating and microwave heating treatment on the yield of grape juice were calculated. In addition anthocyanin contents, total phenolics, color (L, a, b, ∆E, ∆C ) values, viscosity, pH, obrix and total acidity were analyzed before and after pasteurization. The results showed that highest yield were determined for microwave and ohmic heating applied samples; the increasing of yield was found 10% for ohmic heated samples and 15% for microwave heated samples. Microwave and ohmic heating applications before pressing step also increased anthocyanin and total phenolic compounds of grape juice comparing the control samples ( P< 0.05).
关键词：Microwave heating; ohmic heating; thermal heating; mash; grape juice
