Water retain capacity of frozen tomatoes

Abstract

Background. Growth in manufacturing frozen fruit and vegetable products in Ukraine and the positive import dynamics indicate sustainability of demand and prospects of development of refrigeration economic sector of canning industry in Ukraine. Research of natural losses occurring in the plant raw material during freezing and refrigerating storage in order to minimize it is relevant.
The aim of the study is to establish the feasibility of different botanical varieties of tomatoes to freezing by complex organoleptic characteristics, mass loss and ability to retain moisture.
Material and methods. Objects of research are zoned in Ukraine varieties of tomatoes Iskorka, Raisa, Rio Grande Original, Golda and Flora. Tomatoes were frozen at a temperature 35±2 оС below freezing, stored at a temperature 18±2 оС below freezing. The loss of mass was determined by the difference between the mass of frozen and thawed product, water retain capacity by the amount of squeezed juice after freezing and after 2 and 6 months of low temperature storage [16].
Results. The highest mass loss was observed in tomato varieties Golda and Flora (2.86 and 2.42 %), lowest– in the varieties of Raisa and Rio Grande Original respectively (2.18 and 2.20 %), due to a stronger skin of these varieties, that is confirmed with the defined power of resistance to puncture [17].
Varieties Raisa and Rio Grande Original are characterized by higher 2.6 % water retain capacity, due to the varietal characteristics of the fruit.
Violation of tissue microstructure under low below freezing temperatures in the fruit reduces the amount of bound and increases the amount of free moisture. As a result water retain capacity reduces, loss of valuable cell sap increases, that has a negative impact on the organoleptic properties.
Indirectly this is shown by the calculated correlation coefficient between water retain capacity and organoleptic properties of tomatoes presented in Table 2, that averaged 0.85.
Reduction of the overall organoleptic score of varieties Raisa and Rio Grande Original by 19 % turned out to be the lowest compared to other studied varieties.
Conclusion. Tomato varieties Raisa and Rio Grande Original are the most suitable for freezing as during storage their weight loss was lower than in other samples and their water retain capacity was the highest.