Articles
THE CHESTNUT IN THE MODIFIED ATMOSPHERE
Wild trees belonging to Castanea sativa Mill. grow extensively in humid localities throughout the mountains in the Black Sea, Marmara and Aegean regions of Anatolia.
These trees produce a wide range of nuts in terms of size, shape, colour and flavour.
Large, high quality nuts are cultivated in Turkey.
Annual chestnut production is approximately 85 000 tons, and 10% of this produce is exported.
Chestnuts are dry fruits, containing only 45% water.
Because of this and the special structure of the testa, loss of water from the nuts is very fast, and the testa can also dry easily.
Therefore chestnuts should be stored at low temperatures and relatively high humidities.
However, high humidity conditions cause an increase in mould development in nuts, and low temperatures induce particular biochemical problems.
Chestnuts cv. ‘Sarý Aplama’ were harvested in Bursa on 15 November 1994, and on the same day, they were placed into low density polyethylene (LDPE) and polypropylene (PP) bags of 30 × 40 cm.
Thicknesses of LDPE materials were 50, 60 and 100 μm and of PP material was 80 μm.
Then the nuts were stored for 12 months at 0°C and 85 – 90 % RH. Samples were taken at various times: at the beginning of storage, after 6 and 12 months of storage, and following 1 month of shelf life subsequent to 12 months of storage.
Parameters measured were the external appearance of the nuts, incidence of outer mould, seed darkening, sprouting, and weight loss; amounts of starch, sucrose and total carbohydrates.
The effects of 5 different treatments during storage (including control) on quality of chestnuts were examined in this study, and the results of analyses were evaluated.
Normal atmosphere storage (i.e. at 0°C and 85 – 90 % RH) did not give satisfactory results.
However, keeping nuts in a covering material under modified atmosphere (MA) provided good storage conditions.
The best results involving use of covering materials related to storage conditions obtained when using PP 80 μm bags.
This treatment gave superior results compared with the other treatments in terms of mould incidence, deterioration and weight loss.
The results of our analyses were compatible with previous studies conducted on chestnuts.