Biological value of quick-frozen juices with pulp

Abstract

Background. The biological value of the product is due to the essential contents of biologically active substances, which quantity reduces during storage and processing. Rapid freezing is a recognized method of the food conservation. However, there are no juices in the structure of the frozen fruit and vegetable products that could serve as an alternative to the pasteurized juices and fruit ice. Purpose – a research of the biological value of the frozen juice with pulp during low temperature storage.
Material and methods. The objects of the study – quick-frozen juices with pulp, got of the melon, watermelon, apples, carrots, celery, beets of the varieties, included into the State Register [12]. A blend of the apple, carrot and celery juice is got in a ratio of 60, 30 and 10 %, apple and beet – correspondingly 80 and 20 % [13] and the supplements were added: xanthan gum, sugar and ascorbic acid (AA) (Table 1).
In the experimental and control (no additives) variants of juice the contents of AK are defined by the photocolorimetric method on CPK 3-01 [14, p. 7–9], carotenoids [15] and polyphenolic compounds [16, p. 2–4] – for spectrophotometric method on Specord 210, minerals – by X-ray fluorescent analyzer Elva X-med [17]; askorbinatoksydazy activity – for H. N. Pochynok [18, p. 176–178 ]. Research of the samples is conducted prior to freezing and for 9 months of the storage at minus 20 ± 2 оС temperature.
Results. It is defined, that among the biologically active substances of the frozen juices the most resistant to the low temperatures are mineral elements and carotenoids. More labile – ascorbic acid and polyphenolic compounds, the main losses of which occur during freezing, and the little – during the low-temperature storage.
Conclusion. The combination of raw materials of the different chemical composition is a promising direction of increasing the biological value of fruit and vegetable produce.