The Effect of Pre- and Postharvest Calcium Gluconate Treatments on Physicochemical Characteristics and Bioactive Compounds of Sweet Cherry during Cold Storage.

The effects of pre- and postharvest calcium gluconate (Ca-Glu) treatments on some physicochemical characteristics and bioactive compounds of sweet cherry cv. Sweetheart during cold storage were investigated. For preharvest treatments, the Ca-Glu (1%) solution was applied to the cherry trees two times at 21 and 35 days after full bloom stage. Control trees were sprayed with distilled water at the same days. Sweet cherries, sprayed with and without Ca-Glu, were dipped into cold water (4 °C) containing calcium gluconate (1%) for 30 s and only in cold water (4 °C) as control, after harvest Following each treatment, cherries were placed in plastic boxes and stored at 1 ± 0.5 °C and 90 ± 5% relative humidity for 3 weeks. The weight losses of cherries increased over time but calcium (Ca) treatments, especially pre-and postharvest combination, limited these increases compared to control groups. The best result for suppressing the respiration rate of cherries was also obtained from combined treatment. Moreover, combined treatment delayed the losses of titratable acidity, fruit firmness, decay rate and sensory quality in sweet cherries during storage comparison with the pre or postharvest application of Ca-Glu alone. The effect of Ca-Clu treatments on stem chlorophyll content and antioxidant activity was not significant. Preharvest and combined treatments retarded the loss of ascorbic acid content of cherries compared to postharvest and control treatments. The total phenolic and anthocyanin content increased regularly throughout storage, regardless of treatment; however, Ca treatments delayed the accumulation of these compounds. As a result, the combined Ca-Glu treatment could be a promising method for maintaining some physicochemical characteristics and bioactive compounds in sweet cherries during cold storage.

Effect of ozone treatments on the removal of pesticide residues and postharvest quality in green pepper.

The use of ozone as a tool in the storage of some horticultural produces is recommended for all steps from harvest to consumption. However, little is known about its effects on the removal of pesticides and postharvest physiology of fresh peppers. In the present study, the effects of ozone treatment on the removal of pesticides, storage life and quality of green peppers were investigated. Malathion, emamectin benzoate and acetamiprid were applied to pepper plants before harvest. Residue contents of peppers were measured at harvest time and after all treatments to determine the effect of ozone on the removal of pesticide residues. Peppers were subjected to four treatments: immersion in ozonated water (2 ppm) and only tap water (control) for 10 min, exposure to 2 ppm ozone gas in air and only air (control) for 45 min. Treated peppers were stored at 20 °C and 60 ± 5% relative humidity for 8 days, and some quality analyses were performed during storage. Ozonated water decreased, remarkable, pesticide residues in peppers compared to harvest time, but there was no meaningful changes in the samples treated with ozone in air. Ozone treatments suppressed clearly respiration rates and decreased weight losses of peppers compared to control groups. Ozonated water also maintained green color of peppers, with minimum change in h° values. Additionally, sensory quality of peppers was retarded by ozone application during storage. These findings revealed that ozone could be an alternative treatment to extend storage life of green peppers and remove pesticide residues.

Postharvest treatments of salicylic acid, oxalic acid and putrescine influences bioactive compounds and quality of pomegranate during controlled atmosphere storage.

Combined effects of controlled atmosphere and different postharvest treatment (salicylic acid, oxalic acid and putrescine) on bioactive compounds and quality of pomegranate cv. Hicaznar were investigated. Pomegranates were harvested at commercial harvest stage and transported immediately to postharvest physiology laboratory. Fruit were divided into four groups. 1 Control: Dipped into distilled water + 0.01% Tween-20 solution for 10 min. 2 Oxalic acid (OA): Dipped into 6 mM OA + Tween-20 solution for 10 min. 3 Salicylic acid (SA): Dipped into 2 mM SA + Tween-20 solution for 10 min. 4 Putrescine (PUT): Dipped into 2 mM PUT + Tween-20 solution for 10 min. After treatments, pomegranates were stored at 6 °C and 90 ± 5% relative humidity for 6 months in controlled atmosphere (5% O2 + 15% CO2). Weight loss, color, total soluble solids content, titretable acidity (TA), total phenolic content, vitamin C, antioxidant activity and sugar content (glucose and fructose) were determined at 0th, 2th, 4th and 6th month of cold storage. Generally, weight losses were minimized by treatments, especially PUT, compared to control. The level of ascorbic acid significantly tended to decrease throughout the storage in all treatments. Treated pomegranate exhibited higher titratable acidity, total phenolic contents and antioxidant activity compared to control samples. However, PUT was the best among all treatments. The results suggest that SA, OA and PUT have the potential to extend the storage life of pomegranate by delaying quality loss and maintaining some bioactive compound and antioxidant activity.