- astringent, which may be eaten fresh.
- non-astringent, which contain a high levels of tannins and are therefore unpalatable when unripe.
After picking, unripe fruit must undergo a de-astringency treatment and subsequent careful packaging to ensure taste, preserve firmness, avoid storage related diseases and minimize wastage.
Persimmons possess a great many health benefits. Their beneficial phenolic compounds also adversely affect color, taste, flavor, and astringency.
An extended period of storage is required to assure year around supply and facilitate low costs, as well as to enable long range shipping. Fruit may now be stored for up to five months with little waste.
Incorrect storage and handling result in reduced firmness and Persimmon Black Spot Disease (BSD), a fungal disease which can affect up to 50 % of the yield. It can develop during refrigeration with higher incidences occurring after extended storage.
Removal of Astringency from Red Triumph persimmons through Modified Atmosphere Packaging (MAP)
Modified Atmosphere (MA) is essentially a low oxygen high carbon dioxide environment. MA preserves the fruit, facilitates natural ripening and is typically achieved by exposing the fruit to MA for 24 hours.
Experiments were conducted to package the fruit in various packaging configurations to preserve the most beneficial MA and additives, such as 1-MPC to counteract phenolic compounds they produce in storage.
In house packaging capabilities were used in the MAP trials.
According to ROP’s VP of Sales and Marketing, Mr. Gal Wollach, regardless of the traditional treatment, unpackaged fruit spoils soon after being removed from the cold room and if it spoils en route it must be repackaged at the destination at the grower/ shipper’s expense. The research was designed to seek solutions to both anti-astringency and spoilage during storage and shipping. MAP has been seen to address both issues.
The first stage focused on optimal bag design which was later used for larger scale data gathering.
The following tests were conducted:
- Organoleptic evaluation – Flavor and astringency tasting
- Modified Atmospheric conditions
- Skin condition (Alternaria contamination)
FreshCastTM Persimmon (left) vs. naked persimmon (right) – Unripe, 1-MCP treated, persimmons following three months in cold storage (30-32oF) + 7 days in shelf life simulation (68oF). The fruit that was packed in FreshCastTM Persimmon remained firm, presented clean skin and no astringency. The fruit that was stored naked, after removal to shelf life evaluation turned soft, developed extensive infection by alternaria and remained astringent.
Persimmon Long Distance Shipping
ROP, in collaboration with the Laboratory for Storage of Fruit and More – Sharon Fruit has developed a flexible MAP which facilitates off-season export/ long distance persimmon shipping.
A protocol combining 1-MCP treatment with storage at 30-32oF (-1- 0oC) allows for storage for 3-4 months in the harvesting bins. When ready for sale, the fruit is sorted, graded and packed into FreshCastTM Persimmon which further protects the fruit until distribution.
Naturally ripened astringent fruit*
Persimmon Black Spot Disease (BSD) caused by Alternaria was not observed
The fruit remained firm during shipment and shelf life simulation.