FRUITS BIOCHEMICAL COMPOSITION DYNAMICS ОF VARIOUS FEIJOA (ACCA SELLOWIANA (O. BERG) BURRET) CULTIVARS IN CONDITIONS OF LONG-TERM COLD STORAGE

The paper presents research results on the dynamics of the fruits biochemical composition of five feijoa genotypes (Acca sellowiana (O. Berg) Burret) – cultivars ‘Superba’, ‘Dachnaya’, ‘Dagomysskaya’, ‘Sentyabrskaya’ and a breeding form SHV-07 – in conditions of long-term cold storage. The purpose of the work was to evaluate the technological suitability of various cultivars for rapid freezing at –45 oC and subsequent storage at –15 оC for 12 months. The research methodology included monitoring of key quality indicators: the quantitative composition of organic acids (malic and citric) and carbohydrates (fructose, glucose, sucrose) by capillary electrophoresis, the content of soluble solids by refractometry and calculation of the sugar acid index. Significant varietal differences in the resistance of the fruits biochemical composition were established. The greatest resistance and improvement in consumer qualities were demonstrated by the cultivars ‘Dachnaya’ and, ‘Sentyabrskaya’, as evidenced by an increase in the sugar acid index from 4.51 % to 5.88 % and from 12.11 % to 19.40 %, respectively, and the progressive accumulation of sucrose to 95.32 and 97.60 mg/100 g. On the contrary, the cultivar ‘Superba’ and the form SHV-07 showed a significant deterioration in taste characteristics with a decrease in the sugar acid index to 3.56 % and 3.18 %, respectively. The ‘Dagomysskaya’ cultivar was characterized by unstable dynamics with a sharp increase and then a drop in the index to a minimum value of 2.39%. The content of soluble solids increased during the storage period in three of the five genotypes studied: cultivars ‘Dagomysskaya’ (from 12.1 % to 13.9 %), ‘Sentyabrskaya’ (from 10.2 % to 13.4 %) and forms SHV-07 (from 10.8 % to 11.1 %). The data obtained allow us to recommend the cultivars ‘Dachnaya’ and ‘Sentyabrskaya’ as the most promising for long-term cold storage, while the cultivar ‘Dagomysskaya’ requires optimization of storage periods not exceeding 6 months. The results of the study are of practical importance for the development of subtropical fruit crops storage technologies.