Improvement in the Shelf-life of Japanese Strawberry Fruits by Breeding and Post-harvest Techniques

Japanese strawberries have quite high palatability, as well as softness, making them a valuable commodity for local consumption and export. To preserve these characteristics, several unique efforts have been made to improve the shelf-life of strawberry fruits in Japan. This review summarizes the specific breeding and technological developments currently in practice to distribute Japanese strawberries without losing palatability while prolonging the shelf-life. With respect to breeding, the amount and ratio of hydrochloric acid-soluble pectin have been improved, including the hydrochloric acid-soluble pectin to holocellulose ratio, which is related to fruit texture. In addition, although the optimal fruit shape is uncertain, the apex and equatorial parts can be bred to be more rounded in some new varieties. Inflorescence characteristics have also been improved to increase the uniformity of fruit shape and size, which can avoid the need for additional handling while sorting and packing the fruits. With respect to post-harvest techniques, pre-cooling methods, cold chain processes, and highly improved packages have been developed. In particular, the use of hammock-type and elastic film packages mean the strawberry fruit does not make contact with other fruits or trays. These packages also change the acceleration transmissibility under vibration, which can further prevent damage to the fruits during long-term transport. These emerging varieties, pre-cooling and cold-chain processing, and innovative packages are all compatible with sorting and packing robots, allowing for full integration of these processes. Therefore, these innovations and continuous improvements in breeding and packaging are expected to increase the export of Japanese strawberry fruits and provide guidance for achieving a balance between long shelf-life and high palatability in global strawberry production.