Ji Gang Kim

This study was conducted to determine CO2 treatment condition to extend the shelf-life of ‘Seolhyang' strawberry. Fresh strawberries with red color on 80% of the fruit surface were harvested. The samples at two different stages (on the 1st and 3rd day after harvest) were placed in a gas-tight chamber with 0, 5, 15, or 30% CO2 concentration for 3 hours at 4℃. Then, the strawberry samples were immediately packaged in a PET tray and stored at 4℃. The carbon dioxide treatment was effective in maintaining the quality of ‘Seolhyang’ strawberries treated on the 1st day after harvest. These samples had higher firmness, lower redness, softening index, and decay rate compared to samples treated on the 3rd day after harvest. Treatment with both 15 and 30% of CO2 concentration on the 1st day after harvest induced an increase of firmness of ‘Seolhyang’ strawberry after the treatment. Samples treated with 15 and 30% CO2 the 1st day after harvest maintained quality for 10 days. However, samples treated with CO2 on the 3rd day after harvest lost marketability at 10 days of storage. At the atmosphere containing 30% CO2 on the 1st day after harvest was most effective in reducing decay rate and fruit softening, and maintaining bright red color of strawberries among different CO2 concentrations. Therefore, a 30% CO2 treatment within one day after harvest can be a practical postharvest technology to extend shelf-life of ‘Seolhyang’ strawberry.

‘Bagdadagi’ cucumber (Cucumis sativus L.) fruits with half light green skin and tiny white spines grown at greenhouse of the Cheonan-city in the middle part of Korea were harvested in October in 2013, and then stored at 0, 5, 10, 13 ℃, and room temperature for 25 days. Quality and sensory parameters such as CO2 production, weight loss, soluble solids contents, firmness, skin color, yellowing index, overall quality were evaluated during storage. The fruits stored under low temperatures showed the reduced weight loss as well as CO2 production compared with fruits stored in room temperature. But, The fruits stored at 0, 5 ℃ showed high increase of CO2 production after 2 days transfer to room temperature. Soluble solids contents, firmness showed the smallest changes in fruits at all treatments during storage. Chilling injury symptom of watery surface pitting was found in fruits stored at 0 and 5 ℃ and decay after transfer to room temperature. Yellowing was severe in fruits stored at 13 ℃ and room temperature. From the results, storage of at 10℃ was selected as an optimal temperature of ‘Bagdadagi’ cucumber for maintaining storage life up to 20 days.

The role of different washing solutions and contact times was investigated to determine their use as potential sanitizers for maintaining the microbial quality and food safety of fresh-cut paprika. Samples were cut into small pieces, washed for both 90 and 180 s by different washing solutions: tap water, chlorinated water (100 mg/L and pH 6.5–7), electrolyzed water (pH 7.2) and ozonized water (4 mg/L). Then, samples were packaged in 50 µm polypropylene bags and stored at 5 °C for 12 days, followed by an evaluation of the antimicrobial efficacy of the treatments. Various quality and safety parameters, such as gas composition, color, off-odor, electrical conductivity and microbial numbers, were evaluated during storage. Results revealed insignificant differences in gas composition, and no off-odor was observed in any of the samples during the storage period. However, longer contact time resulted in slightly lower hue angle value than a short one for all washing solutions. Moreover, samples washed with ozone washings showed lower electrolyte leakage than other washing solutions. Samples washed for longer contact time except those washed in ozonized water showed increased microbial numbers during storage. Hence, it has been concluded that longer contact time with ozone has positive effects, whereas the other washing solutions adversely affect the microbial quality and safety aspects of fresh-cut paprika.