Postharvest response to high CO2 controlled atmosphere (CA) was studied in the blueberry (Vaccinium corymbosum L.) cultivar Elliot. Fruit was stored at 0 °C, 90% relative humidity and 15%, 18%, and 21% of CO2 and 5% of O2 and in air (0.03% CO2 and 21% O2). Evaluations were performed after 30 and 60 days of storage and an aditional period of 3 and 6 days at 10 °C (ripening period). Parameters meassured were: color (lightness, hue, and chroma), firmness, soluble solids (SS), titrable acidity (TA), SS/TA ratio, pH, weight loss, decay, physiological disorders, and appearance. The CA caused a positive effect, preserving the quality of the fruit in storage, by decreasing the respiratory rate and decay incidence. The 15% CO2 controlled atmosphere presented the best firmness and lowest decay. Acceptable conditions of quality were kept for 60 days of storage.
An experiment was set up to elucidate the causes of differences in harvest time in the adjacent grape-growing areas of Rapel and Sotaqui in the Limari Valley, Chile. Berry samples of `Flame Seedless' were collected from each area, from 10 days after last GA spray until harvest (December to February). Soluble solids (SS), titrable acidity (TA), and SS/TA ratios were analyzed and days from full bloom to harvest, growing degree days, and ambient temperatures were recorded. In Rapel, full bloom was 25 Sept.; the harvest by 16 °Brix, started on 3 Jan., and the harvest by 20:1 SS/TA ratio (min. 15.5 °Brix) on 28 Dec. (11, 16, and 24 days earlier, respectively, than Sotaqui). Degree-days (DD) at harvest (16 °Brix) were 1058 in Rapel and 837 DD in Sotaqui. In the last 50 days prior to harvest, berry acidity was always lower in Rapel, decreasing from 0.87% to 0.47%, while in Sotaqui berry acidity decreased from 1.96% to 0.86%. From 20 Dec. to 2 Jan., the acidity did not decrease significantly (1.96% to 1.84%), but in the next 3 weeks decreased to 0.68%. This difference in the rate of acid degradation is related to the increase in minimum night temperatures in this same period of berry growth. It is concluded that the minimum temperature-dependent rate of organic acid degradation is the main factor influencing the SS/TA harvest index parameter.