QUALITY INVESTIGATION OF FROZEN GARDEN STRAWBERRIES AT PARTIAL DEHYDRATION BEFORE FREEZING

Abstract

Garden strawberry is an important berry culture, consumed fresh and frozen. But a quality of frozen berries is not always at the high level because of changing organoleptic properties, tissues structure and biological active substances losses. It motivates searches for different methods of previous processing of berries before freezing. There was used a production technology of frozen strawberry with partial dehydration before freezing for solving the problem. Garden strawberries of varieties Rusanivka, Honey and Polka were dried on air before freezing (“control” variant), and another part was partially dehydrated in a drying chamber at temperature 40 °С during 30 min (“partial dehydration” variant) with further freezing to final temperature - 18 °С, with packing in packages of polyethylene film with a mass up to 500 g and storing in a refrigerator at temperature -18 °С during 6 months. There were studied main parameters of the chemical composition of fresh and frozen strawberries: content of dry soluble substances, sugars, organic acids, ascorbic acid and sugar-acidic index. Organoleptic quality parameters of frozen strawberries were assessed by the 5-point scale. The experiment was repeated trice. It has been established, that frozen strawberries, partially dehydrated before freezing, saved by 0.2–0.3 % more dry soluble substances, by 0.2 % – sugars, by 7.0-7.9 % – ascorbic acid at a practically equal level of organic acids. The organoleptic mark of frozen partially dehydrated strawberries was by 0.2–0.3 points higher against the control. Among the studied varieties of strawberry, Polka berries got a mark higher by 0.2–0.9 points.