Simulated transit vibration effects on the postharvest quality of persimmon during storage

The mechanical damage of fresh fruit due to postharvest transport vibration is a major problem in the agricultural industry that dramatically impacts product quality. The quality loss is mainly affected by vibration frequency. In this study, the effects of different simulated vibration frequencies (5, 10, and 15 Hz) on the postharvest quality of persimmons were assessed. Changes in physical properties (weight, geometric mean diameter, surface area and volume), mechanical properties (firmness and rupture force) and chemical properties (pH and total soluble solids) were measured during 4 days of shelf life at 20 °C. Transport vibration contributed to the deterioration of the quality of persimmons during storage, resulting in increased weight loss, pH and total soluble solids, and decreased geometric mean diameter, surface area, volume, firmness and rupture force. After 4 days of shelf life, persimmons subjected to vibration frequencies of 5, 10 and 15 Hz exhibited weight losses of 2.12 %, 2.63 % and 3.26 %, respectively, in comparison to 0.83% on the samples without vibration stress (control). The average values of firmness for the control samples decreased 18%, while these changes for samples subjected to vibration frequencies of 5, 10 and 15 Hz, were 34 %, 56 % and 52 %, respectively. The corresponding mean values for the rupture force were 11 %, 19 %, 38 % and 31 %, respectively. The average pH value of the control samples was 5.72 on the first day, which was increased to 6.16 on the fourth day of storage, at a rate of about 7 %, while the increasing rates for the vibration stressed samples with frequencies of 5, 10 and 15 Hz were about 21 %, 33% and 30 %, respectively. Vibration with a frequency of 10 Hz caused the most severe mechanical damage in persimmons.