Comparison of the effects of hydrocooli̇ng and vacuum cooli̇ng on cherry preservation

In this trial, the influences of hydro and vacuum cooling methods on sweet cherry storage and fruit quality were examined. For this purpose, cherry fruit were divided into 3 groups as hydrocooling, vacuum cooling and control. After pre-cooling treatments, fruit were packaged in modified atmosphere bags (MAP) that can hold 5 kg of product and stored at 0 °C temperature and 90±5% relative humidity for 45 days. In addition, fruit that were taken at certain intervals for different quality analysis were also kept for 3 days at 20 °C temperature and 65% relative humidity to simulate shelf-life performance of cherries. In the study, weight loss, fruit colour, total soluble solids (TSS), titratable acidity (TA), fruit firmness, fruit stem removal force, stem browning, total anthocyanin and total chlorophyll content in fruit stem were determined. Furthermore, cracking, pitting and amount of unmarketable fruit were also examined. In the trial, the highest weight loss was detected in the untreated, control fruit, while the lowest weight loss was found in the hydrocooling treatment. Pre-cooling was found to be effective in maintaining fruit colour. Vacuum cooling preserved better L* value and hydrocooling treatment maintained better C* value and the highest ho value was determined in the hydro and vacuum cooling treatments. The effects of different pre-cooling treatments on TSS and TA content were found to be statistically non-significant. Pre-cooling was found to be effective in maintaining fruit firmness compared to the control. The highest fruit firmness was determined in the vacuum pre-cooling. While the highest stem removal force was found in the hydrocooling, the lowest was found in the control group. The most successful pre-cooling method was hydrocooling in preserving the fruit stem browning and stem chlorophyll content. The highest total anthocyanin content was determined in the hydrocooling, while the lowest amount was in the control group. Vacum cooling was found to be effective in reducing amount of cracked fruit, but no statistical difference was found between the treatments in the shelf life conditions. There was no statistical difference in the amount of pitting at the end of the cold storage. However, less pitting occurred in the control and vacuum cooling treatment under the shelf life conditions. Pre-cooling decreased the amount of unmarketable fruit compared to the control. Consequently, hydrocooling was found to be the most successful and effective treatment in terms of preserving the fruit quality during 45 days of storage at 0 °C temperature and 90-95% relative humidity for '0900 Ziraat' sweet cherry variety. This was followed by vacuum cooling and this application has been determined as a promising treatment in pre-cooling of sweet cherries.