Articles
Ascorbic acid as alternative treatment for sulfur dioxide to control rot incidence and keeping the quality of Flame Seedless grapes during short supply chain
Article number
1336_50
Pages
379 – 386
Language
English
Abstract
Sulfur dioxide (SO2) is used commercially either by fumigation or releasing pads to prevent the growth of Botrytis cinerea rot during trading and storage of table grapes (Vitis vinifera L.) but alternative methods are needed to avoid SO2 residues.
The present study focused on comparing the effects of SO2 and ascorbic acid (AA) on delaying rot incidence and keeping the quality of Flame Seedless grapes during short supply chain.
The clusters were harvested early morning at full color stage and total soluble solids (TSS) ≥16 °Brix, immediately transferred to the backing station and treated with one of the following treatments: distilled water (passive control), dual release SO2 pad (active control), 1 and 2 mM AA. Afterwards, the clusters were left to surface dry, randomly packed in perforated (4% ventilation) plastic punnets (approximately 450 g), put in carton boxes, cooled and stored at 0°C with 95% relative humidity (RH). After 10, 20 and 30 days of storage a group of each treatment was transferred to shelf-life for two days at 20°C with 55±2% RH and then evaluated.
Weight loss, rot incidence, berries shattering, total postharvest losses (TPL), berry firmness, total soluble solids (TSS), total acidity (TA), rachis chlorophyll content, rachis browning index (BI), berry color hue angle (h°), visual appearance index (AI) and respiration rate were estimated.
The results showed that SO2 and AA treatments showed significant benefits compared to the passive control.
Compared to the passive control, AA at concentration of 2 mM reduced weight loss, rot incidence, berries shattering, berry softening, BI, and TPL after 20 days at 0°C plus two days shelf-life at 20°C. Up to 20 days of storage, both SO2 and 2 mM AA treatments were statistically equal regarding rot incidence, TPL, berry firmness and BI. The results suggested that it could be recommended to use postharvest application of 2 mM AA as alternative treatment for SO2 to control rot, reduce TPL and keep the quality of Flame Seedless grapes during short supply chain at 0°C with 95% RH for 1-2 weeks plus two days shelf-life at 20°C with 55±2% RH.
The present study focused on comparing the effects of SO2 and ascorbic acid (AA) on delaying rot incidence and keeping the quality of Flame Seedless grapes during short supply chain.
The clusters were harvested early morning at full color stage and total soluble solids (TSS) ≥16 °Brix, immediately transferred to the backing station and treated with one of the following treatments: distilled water (passive control), dual release SO2 pad (active control), 1 and 2 mM AA. Afterwards, the clusters were left to surface dry, randomly packed in perforated (4% ventilation) plastic punnets (approximately 450 g), put in carton boxes, cooled and stored at 0°C with 95% relative humidity (RH). After 10, 20 and 30 days of storage a group of each treatment was transferred to shelf-life for two days at 20°C with 55±2% RH and then evaluated.
Weight loss, rot incidence, berries shattering, total postharvest losses (TPL), berry firmness, total soluble solids (TSS), total acidity (TA), rachis chlorophyll content, rachis browning index (BI), berry color hue angle (h°), visual appearance index (AI) and respiration rate were estimated.
The results showed that SO2 and AA treatments showed significant benefits compared to the passive control.
Compared to the passive control, AA at concentration of 2 mM reduced weight loss, rot incidence, berries shattering, berry softening, BI, and TPL after 20 days at 0°C plus two days shelf-life at 20°C. Up to 20 days of storage, both SO2 and 2 mM AA treatments were statistically equal regarding rot incidence, TPL, berry firmness and BI. The results suggested that it could be recommended to use postharvest application of 2 mM AA as alternative treatment for SO2 to control rot, reduce TPL and keep the quality of Flame Seedless grapes during short supply chain at 0°C with 95% RH for 1-2 weeks plus two days shelf-life at 20°C with 55±2% RH.
Authors
K.A. Farouk, G.A. Baghdady, M.Z. Sultan
Keywords
table grapes, rot incidence, browning, postharvest, ascorbic acid
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