Effect of hydrocooling in the postharvest shelf life of coriander leaves

ABSTRACT:

The reduction of transpiration rate is necessary to maintain the postharvest quality of fresh harvested fruits or vegetables. The pre-cooling technique provides rapid removal of field heat, reducing transpiration rates in many fruits and vegetables after harvest. Coriander leaves are susceptible to rapid dehydration following harvest. The objective of this study was to evaluate the influence of hydrocooling in postharvest shelf life of coriander leaves (Coriandrum sativum ) cv. Português. Bundled coriander leaves (25 g) were subjected to storage at 20°C and 54% RH (control); pre-cooling and storage at 20°C and 54% RH; storage at 5°C and 81% RH; pre-cooling and storage at 5°C and 81% RH. Pre-cooling was performed by submerging bundles into cold water (5°C) for 10 minutes. Pre-cooled bundles absorbed water, resulting in a 4% increase in relative water content (RWC) of the leaves. Seventy-two hours after pre-cooling during 10 minutes, the RWC declined from 89.3% to 88.6% in bundles stored at 20°C. For those coriander bundles stored at 5°C (89.1% to 90.7%) there was no reduction in RWC. Hydrocooling maintained leaf turgidity for 3 and 4 days storage at 20°C and 5°C respectively. Despite leaves remaining hydrated, no increase in shelf life occurred because of chlorophyll degradation. Chlorophyll content of pre-cooled leaves was reduced by 18% (20°C storage) and 19.8% (5°C storage). These bundles had to be discarded because of leaf yellowing. Leaves that were not subject to pre-cooling did not exhibit a significant change in chlorophyll content. These leaves wilted 48 h (20ºC storage) and 96 h (5°C storage) after harvest and were discarded. Storage of coriander at 5°C maintained quality regardless of whether bundles were pre-cooled or not.

Keywords:
Coriandrum sativum; pre-cooling; refrigeration