SUITABILITY OF RHUBARB PETIOLES FOR FREEZING AND LONG-TERM STORAGE

Freezing is one of the most common methods of preserving vegetables. Frozen vegetable semi-finished products are characterized by high relevance, adaptability of usage; therefore, widening of frozen vegetable assortment due to the use of local raw materials having high nutritional value has important social significance. Rhubarb is a promising raw material for processing due to high content of biologically active substances and wide usage in food service industry, confectionery industry, and medicine. The purpose of the study was to determine the ability of local rhubarb petioles to freezing and long storage in terms of some qualityfactors (organoleptic, biochemical, microbiological ones). The study of qualitative profiles was carried out using conventional standard methods. The technology of production of frozen rhubarb petioles consisted of preparatory (sorting, washing, peeling, slicing, washing, draining, packaging, sealing) and main (freezing) stages. It is established that the freezing temperature of minus 32°C does not significantly effect the organoleptic quality (4.76 points for fresh and 4.50 points for frozen goods); the content of organic acids and pectin increased by 10 and 5.9%, respectively; sugar and vitamin C contents decreased by 5.3 and 7.1%. The ability of frozen rhubarb petioles for long-term storage under standard conditions has been proved. They are 12 months, 30 and 7 days at minus 18°C, to minus 12°C and minus 8°C, respectively, under relative humidity of 90-95%, their quality (organoleptic, biochemical) and sanitary (mesophilic aerobic and facultative anaerobic, as well as pathogenic microorganisms, yeast organisms and fungi, E. coli bacteria) factors remaining stable. Nutritional value of frozen rhubarb petioles is as follows: carbohydrate - 3.0 g; pectin - 3.2 g; organic acids - 1.0 g; energy value -14.5 kcal/100 g.