Post-harvest conservation of “Benitaka” table grapes with different SO2−generating pads and plastic liners under cold storage

Abstract

This work aimed at evaluating the post-harvest conservation of “Benitaka” table grape by using different types of SO2-generating pads and perforated plastic liners under cold storage. The grapes were harvested from off-season crop 2018 in a commercial vineyard located at Cambira, PR, Brazil. The completely randomized design was used with four replications in a 2-factor arrangement with an additional treatment [(4 × 3) + 1], and the following factors were evaluated: a) SO2-generating pads (slow release containing 7 g of active ingredient – a.i.; slow release containing 4 g of a.i.; dual release containing 5 g of a.i.; and dual release containing 8 g of a.i.); and b) perforated plastic liners (0.3%, 0.9% and 1.0% of ventilation areas). The additional treatment did not contain any type of SO2-generating pad, only standard microperforated plastic liner (1% of ventilation area). The bunches were packed in 0.5 kg-capacity plastic clamshells, which were placed in a corrugated carton box with the different combinations of SO2-generating pads and plastic liners under cold storage at 1 ∘C with high relative humidity (>90%). The treatments were evaluated at 30 and 45 days after the beginning of the cold storage, recording the incidence of gray mold, shattered berries, stem browning, mass loss and berry firmness. The data were submitted to analysis of variance and the means were compared by Tukey's test at 5%. The use of dual release SO2-generating pads containing 5 g or 8 g of a.i., as well the slow release pads with 7 g of a.i., are efficient to control the incidence of gray mold in “Benitaka” table grapes packaged in plastic clamshells and kept under cold storage at 1 ∘C up to 45 days. In these storage conditions, the use of perforated plastic liners with 0.3% of ventilation area or the micro perforated with 1.0% of ventilation area, result in the lowest bunch mass loss and shattered berries.