Pre- and Postharvest Temperature Conditioning of Greenhouse-grown Sweet Basil

Postharvest shelf life (defined by visual quality) of fresh, greenhouse-grown sweet basil (Ocimum basilicum L.) at 5 °C was only 3 to 4 d due to the appearance of chilling injury symptoms. Plants chill-hardened at 10 °C for 4 h daily (2 h at the end of the light period and 2 h at the beginning of the dark period) for 2 d, before harvesting and packaging, had ≈3 d longer postharvest life. Four- to 6-week-old plants were chill-hardened for 1 week at several periods during the day. Chill-hardening at the beginning of the day extended the average shelf life of cuttings from 4- to 5-week-old plants by 1 and 1.5 d, respectively. Shelf life either was decreased or not affected by the other periods of preharvest hardening. More importantly, postharvest chill-hardening of packaged sweet basil for 1 day at 10 °C in darkness before transfer to 5 °C increased average shelf life by 5 d. Good potential exists for postharvest chill-hardening of packaged sweet basil since this method is effective and convenient.

PRE- AND POSTHARVEST CHILL-HARDENING OF SWEET BASIL

Postharvest shelf life of fresh sweet basil (Ocimum basilicum L.) at 5°C is only 3 to 4 d due to development of chilling injury symptoms. Plants chill-hardened at 10°C for 4 h daily (2 h at end of the light period and 2 h at the beginning of the dark period) for 2 d prior to harvest had 3 d extended shelf life at 5°C. Increasing the duration of preharvest chill-hardening did not further improve the shelf life. Plants were chill-hardened at 10°C for 4 h daily for one week at different periods during the day. Four-, 5- and 6-week-old basil were used in each of three consecutive runs. With the 4- and 5-week-old basil, chill-hardening at the beginning of the day extended average shelf life by 1 and 1.5 d at 5°C, respectively. Shelf life was either decreased or not affected by the other periods of preharvest chilling. Postharvest chill-hardening of packaged sweet basil for 1 d at 10°C before transfer to 5°C increased shelf life by 5 d. Postharvest chill-hardening has potential for reducing chilling injury of packaged sweet basil.