The results of the theoretical explanation and development of the technologies of strawberry storage and canning depending on abiotic and agro-technological factors, refrigerator storage, freezing and canning were presented in the dissertation work.
Average mass (6,9…15,1 g), volume (5,5…13,3 cm3), density (0,8…1,0 g/cm3) and marketable estimation of strawberries depend on a cultivar, age of the plantation and alternation of harvesting to a great extent. Strawberries of cultivars Pegas, Honey and Dukat have the largest average mass, those of Dukat and Pegas – the largest volume, strawberries of cultivars Polka and Festyvalnaromashka have the largest density.
Berries are covered with a thin layer of epidermal cells, its thickness is not more than 5 µκ, mesocarp is presented with parenchyma cells, as wide as 50…75 µκ andas long as 150…225 µκ with a thin wall and large intercellular spacing which do not protect a fruit from evaporation during its storage, mechanical effects and penetration of microorganisms.
Depending on a pomological cultivar and weather conditions, strawberries accumulate in their composition, on the average, 11,3…14,1 % of dry matters, including 8,5…10,0 % of soluble dry substances, 0,90…0,96 % of pectin substances, 5,8…8,2 % of sugars; 0,82…1,06 % of organic acids; 55,9…99,5 mg/100 g of ascorbic acid; 33,2…56,3 mg/100 g of phenol compounds, among them58,1…81,0 % of anthocyanins; 3297,9…5218,9 mg/100 gof dry amino acid mass; 12 mineral elements. Berryaromaisformedundertheeffectofvolatilecompounds: 2,5-dimethyl-4-methoxy-3(2Н)-furanone (mesifurane),2,5-dimethyl-4-oxy-3(2Н)-furanone (furaneol), ethyl 2-methylbutanoate, ethylbutanoate, trans-2-hexanal, ethyl 2-methylbutanoate, methylizobutanoate, hexalacytate.
A complex of objective indicators of consuming ripeness of various strawberry pomological cultivars was established. Harvesting terms were scientifically grounded based on the effect of abiotic factors.
Storage advantages of strawberries, grown without mulching, were established due to the decrease of respiration intensity by 0,2…0,7 ml СО2•kg/hr, the increase of mass losses by 0,4…1,3 % and higher output of marketable produce by 5,6…10,6 %. It has been studied that during strawberry shelf-life the content of complex ethers decreases by 66,0%, that of furanic compounds –45,3 % andanthocyanins. It has been proved that every hour of a delay in strawberry freezing increases mass losses by 0,1…2,3 %, and the latter are responsible for the changes of freshness characteristics.
The effect of freezing on strawberry quality indicators depending on farm practices was studied. It has been proved that mass losses and cryoresistance of frozen strawberries depend on their size at the largest cross-sectional diameter, and optimal size of frozen strawberries is 18…25 mm.
The ways of preliminary processing of strawberries before freezing with the use of citric, ascorbic acids and sugar-pectin solution were improved. It has been established that preliminary treatment of starwberries before freezing in water solution 0,5% of citric acid improves organoleptic evaluation of strawberries by 0,8 point, decreases mass losses by 0,2%, ascorbic acid by 21,3%, and partial osmotic dehydration in sucrose solution together with 1% of citric acid preserves major components of the chemical composition, prevents ascorbic acid losses by 1,9…19,3% and improves organoleptic characteristics of strawberries. Preliminary treatment in 2% sugar-pectin solution retains microstructure of frozen strawberries, decreases mass losses by 0,9…1,6%, ascorbic acid – by 13%, increases cryoresistance of the berries up to 98%, organoleptic evaluation by 0,6 points, saves “height index”.
Recipes of frozen pastelike mixtures, based on starwberry paste or when it was added, were optimized. Frozen pastelike mixtures, the main component is strawberry paste with the addition of: apples sour cherries, black currants, apricots, dogwood, plum and pumkin, increase vitamin value of the produce by 4,2…8,9 times and improve organoleptic characteristics.
The change of color of various processed products of different pomological strawberry cultivars during the storage was studied. The storage terms of canned strawberry was scientifically grounded: natural non-clarified strawberry juice –6 months,jam and stewed fruit – 12 months, marmalade – 18 months, jam and stewed fruit (cv. Polka) – up to18 months.
The technologyof sterilized strawberry jam with the addition of 25% of recipe amount has been improved, which allows to get expected physical-chemical and organoleptic indicators of quality with the content of dry substances not less than 62%, mass sugar share – 56…57%, titrated acids – 0,6…0,8%, pectin substances –0,76…0,84%.
