Salicylic Acid Maintains Quality of ‘Chimarrita’ and ‘Maciel’ Peaches Under Cold Storage

Abstract

Aims: The objective of this work was to evaluate the efficiency of postharvest application of salicylic acid on Chimarrita and Maciel peach cultivars under cold storage. Study Design: The experiment was conducted in a completely randomized design with four replications and 15 peaches per experimental unit, following a 4x3 factorial design for each cultivar, 4 treatments and 3 storage periods for both cultivars. Place and Duration of Study: This work was executed at LabAgro/Fruticulture, Federal University of Pelotas, Rio Grande do Sul state, Brazil, between November 2013 and February 2014. Methodology: Postharvest application of salicylic acid was performed in both cultivars from the 2013/2014 crop by spraying the fruits with the solution (salicylic acid + distilled water + ethyl alcohol) and then letting them air-dry. The following treatments were used: T1- Peaches without the treatment solution (distilled water + ethyl alcohol (control); T2- Peaches treated with 0.5 mmol.L-1; T3- Peaches treated with 1.0 mmol.L-1; T4- Peaches treated with 1.5 mmol.L-1. The fruits submitted to the treatments were cold-stored at 1.0 ± 0.5°C and 85-90% RH, during 30 days. Weight loss (%), DA index, flesh firmness (N), soluble solids content (°Brix), rot incidence (%) and soluble pectin (g.100 g-1), were evaluated after a storage period of 10, 20 and 30 days plus two days for commercial simulation. Results: Chimarrita cultivar: The predict value for weight loss at the stationary point was 3.27%, obtained with 1.33 mmol.L-1 of salicylic acid at day 12. Data regarding rot incidence showed to be adjusted to the regression model (F = 3.90; p = 0.007), with R2 of 0.68 e R2adj of 0.64. During the optimization process, the roots of the auxiliary equations were positive and negative in magnitude, indicating the saddle point as the stationary point. Under this condition, 35.4% of rotting was registered for 0.85 mmol.L-1 of salicylic acid, after 23 days. Maciel cultivar: The predict value for weight loss at this stationary point was 5.18%, reached with 0.56 mmol.L-1 of salicylic acid after 21.19 days. Flesh firmness findings adjusted to the regression model (F = 61.87; p< 0.0001), with R2 of 0.89 and R2adj of 0.87. During the optimization process, the roots of the auxiliary equations were positive and negative in magnitude, indicating the saddle point as stationary point, and the predict value was 35.7N for 0.75 mmol.L-1 of salicylic acid in 20 days. Conclusion: Postharvest application of Salicylic acid at 1.0 mmol.L-1 was efficient in maintaining the quality of the Chimarrita cultivar at 20 plus two days for commercial simulation. As for the Maciel cultivar, a concentration of 0.5 mmol.L-1 of salicylic acid was more efficient for the same storage period.