Influence of ripening stage and polyethylene packaging on cold storage of plum

Aiming to verify the influence of ripening stage and polyethylene packaging on cold storage of plum (Prunus salicina Lindl.) Amarelinha cultivar, an experiment was conducted in Embrapa - Centro de Pesquisa Agropecuaria de Clima Temperado (CPACT), Pelotas, RS State Brazil. Three ripening stage fruits were used: green, semi-ripe and ripe, packed or not with polyethylene bags. Fruits were cold stored at 0 degrees C and 90-95% RH during 14, 28 and 42 days, followed by three days of market simulation at ambient temperature (25-26 degrees C). Polyethylene bags reduced weight loss for less than 1% during cold storage while unwrapped fruits lost up to 7% of weight, showing wilt symptoms after 28 days, mainly for ripe stage. The firmness and titratable acidity decreased along the experiment for the three ripening stage. The high acidity decrease caused fruit overripening mainly for 42 days of cold storage. There was no fruit internal breakdown and decay incidence increased at 42 days. Cold storage is recommended for this cultivar until 28 days.