Effects of freezing rate on the quality of cherry tomatoes

Abstract

In this study, the effects of different freezing rates on some physical and chemical quality properties of cherry tomatoes were investigated. Cherry tomatoes were frozen slowly at-18°C at the freezer section of the home type refrigerator and quickly at-30°C in the modified freezer cabinet which is capable of blowing air at a speed of 1.2 m/s at-30°C, designed and produced by Bosch und Siemens Hausgerate GmbH (Cerkezkoy, Turkey). The freezing rates were calculated on the bulk basis of the samples in the middle, bottom and top positions. The freezing rate in the middle for-30°C found as 1.55±0.16 (cm/h) which was slow freezing and 0.11±0.01 (cm/h) for-18°C between 4 and-15ᵒC which was in the range of quick freezing. Drip loss, total dry matter content, total soluble solid content (ᵒBrix), color values, pH, ascorbic acid, total phenolic content, titration acidity and lycopene were investigated for cherry tomatoes frozen at different rates. Drip loss values were 11.01 ± 0.21% for quick frozen cherry tomato samples and 19.95 ± 0.44% for slow-frozen samples. The decrease in ᵒBrix value of slow frozen sample was more than quick frozen samples. Brightness and a/b values of the quick frozen tomatoes were better compared to the slow frozen ones. Ascorbic, phenolic and lycopene contents were found higher in quick frozen sample.