Lychee fruit, which is harvested fully mature, requires careful post harvest preservation. Traditional methods for preserving the fruit’s color include immersion in acid solutions, which spoil the taste and are proscribed in several countries.
ROP has developed a unique packaging method called ExtendCastTM that keeps the fruit fresh, preserves its attractive color and minimizes weight loss without resorting to chemicals.
In addition, the retail bag may be adapted to prevailing temperatures and length of storage requirements. It also minimizes weight loss and preserves the delicious lychee taste.
The Natural Approach – Proposed Protocol
Harvest in the early morning. The fruit is picked in clusters, placed in large bins and removed to a shaded area before separation into 12-20Kg (25-44lbs) plastic totes. The fruit is kept rinsed with fresh water and covered to minimize dehydration.
Delivery time to the packing house should not exceed 2 hours after picking. Upon arrival the fruit is submerged in disinfectant (chlorine dip or equivalent) and is then air tunnel dried to remove excess water.
Moist room temperature fruit is packed into ExtendCastTM bags and heat-sealed. Bags are then put into master cartons and placed in cold storage at 2-4°C (36-39°F) for the duration of the required storage time
ExtendCastTM Lychee Retail Bag Properties
- Atmospheric Conditions
ExtendCast’s Packaging Oxygen Transmission Rate (OTR) is calibrated to accommodate various temperature profiles typical of domestic and export logistics. For extended storage periods of 21-28 days (Export), stable 2-40C (36-39°F) and for shorter storage periods of 8-10 days (Domestic) at 16-180C (60-64°F).
- Weight Loss
Very low weight loss is achieved when using ExtendCastTM bags. This has a positive effect on preserving the fresh appearance of the peel, which is otherwise prone to cracking. Slightly greater weight loss was observed with fruit stored at ambient temperatures compared to fruit in cold storage.
Multiple, independent, blind flavor tests confirm that no off-flavor or after-taste were recorded with ExtendCastTM packed lychee under either export or domestic conditions.
The fruit flavor and aroma are described as fresh, natural, juicy and sweet, and distinctively different to fruit commercially treated with sulfuric acid.
Sulfuric acid treated fruit was referred to as ‘spoiled’ and ‘sour’ when flavor tested after natural lychee fruit in ExtendCastTM packaging.
There is little doubt that ExtendCastTM packaging promises to revolutionize lychee post harvest treatment.