Storing Santol at Different Temperatures : Preliminary Experiment

The experiment was conducted toward the end of the santol season when many of the santol trees were harvested already. Few trees that have fruits are late bloomers. The fruits are yellow to orange ripe. The flavors are at their optimum.

The chosen fruit is a semi-bangkok variety. It is smaller than bangkok but bigger than native.

The fruits where gathered about 7‘o’clock in the morning, to prevent injury from sun’s heat. Sigpaw, nylon basket on a long bamboo pole, was used to pick santol off the branches. Care was observed to avoid falling fruits to ground. All fallen fruits were not included.

Fruits were selected. Too large and too small fruits were discarded. Divided to group of 12, each having 5 fruits. The first six groups were pack in polyethylene bags and subjected to different temperatures and humidity. Two holes were punched on each bag to avoid too much accumulation of carbon dioxide and moisture. It was also expected to prevent moisture condensation.

Creating and maintaining different temperature ranges is hard and expensive. The fruits were stored in the following places as a low cost alternative:

Temperature variations:

below freezer compartment: 10ᵒC, 93 RH
Chiller: 14ᵒC, 95 RH
Room temp: 25ᵒC, 80 RH
behind refrigerator grill: 31ᵒC, 88 RH
House attic: 36ᵒC, 70 RH
beside gas stove : 39ᵒC, 40 RH

Atmosphere variation

Not packed
Packed in plastic labo, polyethylene bags

Temperatures and relative humidity in refrigerator were near constant through experiment duration. Values of room temp, behind refrigerator grills and house attic were average during the day and expected to drop at night-time. Temperature and RH of “beside gas stove” were gathered during cooking hours. Santol experienced to harsh temperature for about 1 1/2 hours three times a day.

OBSERVATIONS

Observations were done after 2 days and 6 days. Observations in between were not done as the author went out of province.

Water Condensation

Among the groups pack in polyethylene bags, the group stored below freezer compartment got the most condensed moist accumulation, followed by the group stored in chiller compartment. It was too excessive that it made the fruit skin wet. The water coming out of santol plus the moisture coming from inside the refrigerator might have contributed to this much moist condensation.

The following is a list of groups in accordance to severity of moist, the first had the most moist.

below freezer
chiller
beside gas stove
attic
back of refrigerator grill
room temperature

The next was the group beside gas stove. The intermittent exposure to 39ᵒC and relative humidity of 40 had caused too much moist accumulation. Too much heat caused excessive water evaporation and condensed as the two bag holes were not enough to bent it off.

Most Rotten

The following is a list of groups in accordance to severity of rotting, the first had the most rotten.

Below Freezer in PE bags
Below Freezer
Room temperature
Attic PE
Attic
beside gas stove PE
beside gas stove
Beside Refrigerator grill
Beside refrigerator grill PE
Room PE
Chiller
chiller PE

Below freezer storage regardless of whether it was bagged or not were the worst. All the superficial skins suffered browning to the point that they were not pleasing to the eye. The chilling injury passed thru the rind and made the pulp watery.

Attic, both packed and unpacked, suffered severe damage, with half of the fruits rotten and inedible. Modifying the storage atmosphere at this temperature did not affect storage quality. The same was true for storage beside gas stove. The intermittent exposure to high temperature did increase the transpiration rate but did not noticeably increase the rotting.

Fruits packed in polyethylene bag and stored under room temperature withstand the six days of storage with minimal skin damage, few brown spots around. The same as true for beside refrigerator grill treatments, both packed in PE and not packed.

The group which had the most preserved quality was the chiller packed in polyethylene bag. It has the original bright yellow skin, bright rind and a nice inner pulp that was perfectly edible. All of the five fruits are of the same state. Other fruits that were stored in chiller but not packed in polyethylene bags were in the same condition but their skin were brown due to chilling injury.

stored in chiller packed in PE bagsAfter the simple experiment, the recommended storage temperature for future experiment is 14ᵒC, packed in polyethylene bags with two holes. It may still last up to three weeks. If the technology beneficiaries are of limited budget, packing the fruits in polyethylene bags and maintaining a temperature of 25ᵒC may do. Future experiment should focus on these two.


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