KOREASCHOLAR

Maturity at harvest is the key factor influencing storage life and the final quality of fruit. This study examined how the firmness of ‘Sweet Gold’ kiwifruit at harvest affects its post-ripening characteristics to create a maturity chart. Throughout the storage period, firmness decreased in all categories of fruit: hard, medium, and soft. ‘Soft’ fruits lost 40% of their firmness within 2 days after harvest, whereas ‘hard’ fruits remained firmer than soft fruits throughout the storage period and had the least soluble solids content, indicating a slower ripening progression. The acidity of ‘soft’ kiwifruit was very low from the day of harvest, suggesting that it was utilized as a respiratory substrate during ripening. The a-values (indicating redness) for ‘soft’ fruits gradually increased until day 6, stabilizing thereafter. ‘Soft’ fruits exhibited the highest ethylene production rate throughout storage. They showed a climacteric rise in ethylene on day 13, compared to ‘medium’ and ‘hard’ fruits, which exhibited increases on days 19 and 21, respectively. This data can help determine the optimal ethylene treatment duration for ripening ‘Sweet Gold’ kiwifruit. The firmness of ‘Sweet Gold’ kiwifruit at harvest is a crucial factor in determining its marketability and can effectively serve as a maturity index to estimate its shelf life.

Abstract
1. INTRODUCTION
2. MATERIALS AND METHODS
    2.1. Plant material
    2.2. Firmness
    2.3. SSC, Titratable Acidity (TA), and °Brix AcidRatio (BAR)
    2.4. Fruit surface color
    2.5. Ethylene production
    2.6. Statistical analyses
3. RESULTS
    3.1. Fruit quality at harvest
    3.2. Changes in firmness
    3.3. Changes in SSC, TA, and BAR
    3.4. Changes in flesh surface color
    3.5. Changes in ethylene production rate
4. DISCUSSION
5. CONCLUSIONS
CRediT authorship contribution statement
Declaration of Competing Interest
ACKNOWLEDGEMENTS
REFERENCES

• Haejo Yang(Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea)
• Siva Kumar Malka(Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea)
• Min-Sun Chang(Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea)
• Ji Hyun Lee(Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea)
• Yoonpyo Hong(Postharvest Technology Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea)
• Me-Hea Park(Vegetable Research Division, National Institute of Horticultural and Herbal Science, Wanju 55365, Republic of Korea) Corresponding author