Impact of harvest time on cold storage performance in Kiwifruit

In the present study the fruits of the cultivar 'Hayward' kiwifruit were harvested at a total soluble solid content of 5-6 % (Harvest I, H1), 6.1-7.0 % (Harvest II, H2), 7.1-8.0 % (Harvest III, H3) and 8.1-9.0 % (Harvest IV, H4) and stored at 0 +/- 1 degrees C temperature and 85-90 % relative humidity (RH) conditions for 6 months. Changes in fruit flesh color, flesh firmness, soluble solids content (%), titratable acidity (TA), individual sugars (sucrose, glucose, fructose), ascorbic acid content, antioxidant activity (DPPH, FRAP), total phenolic content, weight loss and marketable fruit were observed at one month intervals. In kiwifruits, an increase was observed in health benefit compounds such as ascorbic acid and total phenolic content, antioxidant capacity by progressing of harvest times. However, early (H1) and late (H4) harvest times led to faster loss in fruit firmness, significant loss in titratable acidity and soluble solid content, higher weight loss rates in fruit. The results show that the second and third harvest times, when the soluble solids content of the fruit is 6.1-7.0 % (H2) and 7.1-8.0 %(H3), seem to be optimum in terms of quality preservation for 'Hayward' kiwis grown in the Black Sea Coast and provides health benefits with a higher marketable fruit rate after 180 days of cold storage. Finally, there was a positive correlation between SCC and sucrose, glucose, fructose. There was a negative relationship between fruit SSC and flesh firmness, TA, L*, C*, h degrees after 6 months of storage. And also there was a negative correlation between weight loss and marketable product quantity, fruit flesh firmness.