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This study evaluated the effects of four different gibberellin-pastes (GAP) on fruit quality and storability of niitaka pear in 2014 and 2015 consecutive years. Pear fruit stalks were treated with dongbu GA gold, nebaekeo, busa, and GA hyeophwa-pastes at 35 and 37 days after full bloom, respectively. After harvest time, the fruits were stored at 0°C for up to 180 days. In both years, fruit weight was 6.2-21.3% higher in GAP-treated fruits than the control fruits at harvest. In 2014 year, flesh firmness was higher in control (70.6 N) than the GAP-treated fruits (54.4-64.6 N) at harvest, but it was not different in all treatments in 2015 year. The titratable acidity (TA) at harvest was also higher in control than the GAP treated fruits in 2014 year. The soluble solids content (SSC) at harvest was slightly lower in control than the GAP treated fruits in both years. During cold storage, flesh firmness was decreased in all treatments, whereas the fruits treated with nebaekeo GAP had the lowest flesh firmness (39.4 N) after 135 days of the storage. TA was a slightly higher in control (0.19%) than the GAP-treated fruits (0.14-0.17%) after 180 days of storage. However, SSC was higher in the fruits treated with dongbu GA gold and GA hyeophwa-pastes than the control fruits during storage. Therefore, GAP-treatments increased fruit weight and SSC than control, but flesh firmness and TA of GAP-treated fruits were reduced after 180 days of the storage.

This study was carried out to investigate the effect of a preharvest treatment with aminoethoxyvinylglycine (AVG) on fruit quality during ambient temperature storage of ‘Fomosa’ plum (Prunus salicina). Flesh firmness of the control fruit during storage decreased to less than 2.00 N after 12 days of storage, but AVG treated fruits remained above 4.00 N after 20 days of storage. The amount of ethylene produced in the control fruit began to increase from 12 days after storage and rapidly increased to 90.0 μL/kg/h after 20 days of storage. However, AVG treated fruits showed low ethylene production of 20.0 μL/kg/h after 24 days of storage. The titratable acid (TA) of control fruit decreased from 1.15% at harvest to 0.87% at 20 days after storage, but AVG treated fruits remained high at 1.04-1.08% after 24 days of storage. The redness (a*) of the fruit peel at harvest was not statistically significant but increased in the AVG treated fruits during storage. Therefore, pre-harvest AVG treatment in 'Formosa' plums was effective to maintain the quality of fruits by decreasing the ethylene production and maintaining flesh firmness and TA of fruit during ambient temperature storage.

The efficacy of 1-methylcyclopropene (1-MCP) in maintenance of apple fruit quality can differ depending on apple cultivar, ethylene content at harvest, 1-MCP concentration, the interval between harvest and 1-MCP application, and the number of applications. In this study, we investigated whether the 1-MCP concentration and its application frequency differently affected fruit quality attributes of the two new apple cultivars ‘Arisoo’ and ‘Picnic’. The fruits were treated with 1-MCP (as single or double treatments) at the rate of 0 μL L−1 (control), 0.5 μL L−1, 1 μL L−1, 0.5 + 0.5 μL L−1, and 1 + 1 μL L−1 for 18 h, and they were stored at 0 °C up to six months. Comparatively, the fruit qualities of 1-MCP treated fruits were higher than that of the control during cold storage, with a higher suppression of internal ethylene content and a slower reduction of titratable acidity in 1-MCP treatments than the controls throughout the cold storage in both cultivars, regardless of the concentration and number of applications. Reduction of fruit firmness and soluble solid contents were maintained by single application of 0.5 μL L−1 1-MCP in ‘Arisoo’ apple, while double application of 0.5 + 0.5 μL L−1 was needed in ‘Picnic’ cultivar. The effective concentration for weight-loss reduction was found to be the single application of 1 μL L−1 1-MCP in both ‘Arisoo’ and ‘Picnic’. Conclusively, 1-MCP as single treatment at the rate of 0.5 μL L−1 could be sufficient in inhibiting ethylene action and maintaining fruit quality losses during cold storage, particularly in ‘Arisoo’. However, double application of 1-MCP might be necessary for some quality attributes in ‘Picnic’ apple.

Supplementary file_Primer and PCR_Nay Myo Win_Manuscript_foods

Despite an increase in the use of 1-methylcyclopropene (1-MCP) to delay fruit softening, the role of 1-MCP in the modification of cell wall pectin to maintain apple fruit firmness during storage is poorly understood. Hence, in this study, we investigated whether 1-MCP treatment delayed fruit softening through pectin modification, in “Hwangok” and “Picnic” apple cultivars, stored up to six months at 0 °C. In both cultivars, 1-MCP-treated apples maintained firmness and exhibited lower internal ethylene concentrations compared with untreated fruit. The depolymerization of pectin in all pectin fractions was attenuated in 1-MCP-treated fruit compared with untreated fruit. In addition, a peak location shift was observed in the molecular mass profile of untreated fruit. Neutral sugar contents (arabinose and galactose), which typically change as fruit ripen, were effectively maintained in 1-MCP-treated fruit. The activity of four important enzymes involved in pectin modification (exo-polygalacturonase, pectin methylesterase, β-galactosidase, and α-L-arabinofuranosidase) was reduced in treated fruit compared to the control. Furthermore, 1-MCP treatment reduced the expression of pectin-degrading candidate genes (MdPG1, MdPME1, Mdβ-GAL1, Mdβ-GAL2, and Mdα-ARF2). This study suggests that 1-MCP maintains cell wall pectin and delays the softening of the two apple cultivars by reducing the solubilization of polyuronides and neutral sugars, and limiting the activities of cell wall hydrolysis.