Study On Quality Changes And Maintenance Of Post-Harvest Garlic Scapes During Modified Atmosphere And Cold Storage

This study was conducted to investigate the quality parameters of five garlic scape cultivars in 2014-15 and two cultivars with different pretreatments in 2015-16 respectively in modified atmosphere and cold storage.As garlic scape is a perishable commodity therefore long storage is of utmost importance both for producer and consumer.Garlic scapes can be stored in modified atmosphere storage and can be supplied for a long time but the consumers complained about the quality especially the taste deterioration as compared with freshly harvest garlic scapes.This research was conducted to investigate the main reason for taste deterioration and to improve the quality of scapes in the modified atmosphere long term storage.To the best of our knowledge,allicin and ethylene were first time measured through HPLC and TRACE GC Ultra Gas Chromatograph respectively in garlic scapes.The research consists of three experiment which are summarized below.In the first experiment,five commercial cultivars of garlic scapes were subjected to a modified atmosphere?O₂=2-5%,CO₂=3-6%?at temperature 0±0.5°C,RH 85-95%,for 140-224 days to document the quality and related changes in components during storage in two consecutive years.Polyphenols,flavonoids,allicin,and 2,2-diphenyl-1-picryl-hydrazl?DPPH?as well as the ferric ion reducing antioxidant power?FRAP?,metal chelating capacity?MCC?,and hydroxyl radical scavenging activity?HRSC?were analyzed to study overall antioxidant properties of garlic scapes during storage.The storage life was 224,196,196,168,and 140days for G025,G107,G2011-4,G110,and G064.G025 had the highest total polyphenol concentrations at 140 and 168 days in 2014 and 2015,respectively,whereas G2011-4 had the lowest concentrations of total polyphenols.The highest total polyphenols,total flavonoids and allicin concentrations were observed in G025,whereas G2011-4 displayed the lowest concentrations of total polyphenols and allicin in both years.For all cultivars,total flavonoid concentrations decreased with time.The highest weight loss was observed in G064 both in2014 and 2015.The antioxidant capacity of G025 and G110 was higher than that of the other cultivars.DPPH and HRSC were highest in G025,and MCC and FRAP were high in G110and G107 in both years.These results demonstrate that cultivar influences the rate of garlic scape deterioration,chemical composition properties and antioxidant activities.In second experiment,we investigated the effect of 1-methylcyclopropene?1-MCP?and Preservative Xianfeng?PXF?treatments on postharvest characters,total polyphenols,total flavonoids concentrations;allicin,ethylene evaluation,and antioxidant capacities in two garlic scapes cultivars.Garlic scapes were treated with 1-MCP and PXF for 24 hours at 1and stored at 0±0.5 temperature with 85-95%relative humidity for 168 days.Both preservatives were found effective regarding different parameters of post-harvest storage.Total polyphenol?TP?and allicin were more in treatments G025 1-MCP and G064 PXF.Total flavonoids?TF?concentration was more in treatments G025 PXF and G064 PXF and ethylene was low in G025 1-MCP and G064 1-MCP.Among antioxidant capacities DPPH and FRAP was high in treatments G025 PXF,G064 PXF and G064 1-MCP.HRSC and MCC were high in treatments G025 1-MCP,G064 1-MCP,G025 PXF and G064 PXF.G025 1-MCP and G064 showed the lowest weight loss.Treatments 1-MCP and PXF significantly decreased changes in the total polyphenols,total flavonoids,ethylene evaluation,and antioxidant activities.The results demonstrated that 1-MCP and PXF treatments were effective in maintaining the biochemical properties and extending the postharvest life of garlic scape in different cultivars.The third experiment highlights the effect of removing different plant parts on the biochemical changes in the garlic scape of cultivars G064 and G025 during modified storage at a temperature of 0±0.5°C and RH of 85-95%for 168 days.Total polyphenols?TP?,total flavonoids?TF?,the concentration of allicin,ethylene production and the antioxidant potential were evaluated and analysed by using four different assays.Statistically significant differences were observed between the two cultivars.Total polyphenols,allicin concentration and ethylene production were the highest in G064,while the total flavonoid concentration was the highest in G025.Removing the top resulted in the highest levels of total polyphenols,total flavonoids,allicin and the lowest ethylene and weight loss in both cultivars.The antioxidant capacity was also significantly higher when the top was removed than with other treatments in both cultivars.2,2-diphenyl-1-picryl-hydrazl?DPPH?,hydroxyl radical scavenging activity?HRSC?,ferric ion reducing antioxidant power?FRAP?and metal chelating capacity?MCC?were higher in cultivar G064 compared to G025.Overall,the results suggest that the scape of G025 and G064 with the tops removed is the best treatment to maintain these biochemical changes.The variation in chemical composition in garlic scapes among different cultivars was investigated for the first time.Based upon our experiments,it is suggested that modified atmosphere storage is applicable for 224 days for garlic scapes which did not affect negatively the chemical composition of cv G025.1-MCP and PXF treatments were effective in maintaining the biochemical properties and extending the postharvest life of garlic scape in different cultivars.Scapes of G025 and G064 with the tops removed is the best treatment to maintain biochemical changes.