Extending Tomato Shelf Life With Rice Straws

A postharvest technology developed by Mariano Marcos State University. Tomatoes if harvested properly and stored inside boxes with rice straws last for 60 days. This is a pretty good trick during oversupply from January to April. Farmers can sell their produce during off season when the price is expected to be higher.

Here it goes. Get a corrugated box of good condition. Lay 2-3 centimeters of dried rice straws. Arrange a single layer of mature green tomatoes. Put rice straws again and repeat until covered to the top. Set straws as top layer.

Remember! Tomatoes should be in mature green stage. Harvested in the morning. Free from bruises, diseases and ripes.

I see three basic conditions why this simple but useful technique works.

1) The sealed carton somewhat creates a reduce air and cold condition which ultimately slows down tomatoes physiological processes, retarding ripening and rot.

Of course the farmer should try their best to protect the carton itself. It should be stored in dry, cool and well ventilated area. Leaving it under the shine of sun is an effort wasted.

2) Mature green stage and free from damages. We all know, trying to prolong shelf life of red ripe fruit is futile. We choose mature, green and hard and try to slow down the ripening rate. The period from green to soft red is stage is the shelf life. The longer, the better.

We exclude ripe and damaged fruits not only because they ripe and rot easily. Ripe tomatoes and damaged parts release a ripening hormone called ethylene.

3) Rice straws also serve as cushion, preventing damage in between tomato layers. Improperly arranged straws won’t work well as intended.

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.

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.

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.

Santol Fruit: Causes of Postharvest Losses

There are three major causes of postharvest losses of Santol Fruit. They are: lack of available processing technologies, lack of storage facilities and lack of knowledge on proper handling.

kalan casualty

1) Lack of available processing technologies. Perhaps it is the major cause of postharvest losses. When the santol Bangkok variety came to existence, lots of farmers in our area planted many trees and started getting bountiful harvest after several years. However, the santol fruit has very few processing technologies available and no commercially available product is made from such. There are few available on market but no being produced on commercial scale. These lead to a very low market demand bringing down the price per sack to only 50 pesos. Such low price cannot cover for the cost of harvesting and hauling. Santol fruit only commands higher price at the beginning of the season. It dramatically drops towards the middle forcing many farmers to leave the fruits rotting on trees.

2) Lack of cold storage facilities. Farmers, wholesalers and retailers never have the means to store the products at colder temperature.  The marketing channels have to do their best to sell the product before it reach its end life. The best way to do this is lower the price instead of extending the life span. If they are unsuccessful, all the commodity left behind will be gone to rot.

3) Lack of knowledge on proper handling. The fruit has a very low demand and so postharvest studies are also rare. There is limited information about shelf life, cold storage and proper packing, including modified atmosphere packaging.

Santol is usually packed in sacks with the bottom and top cushioned with santol leaves for damage protection. However, the thin sack and the leave cushioning are not enough to protect it during transport. Two sacks are secured with ropes on side of horse and another sack on horseback. The handler thinks the santol thick rind can handle the pressure.

The sacks are usually left under the heat of sun for several hours to days. It has no protection against extreme heat and considerable moist from rain.

During vehicular transport, the sacks are pack in such a way to maximize the space. The hired vehicle should carry the maximum possible load to cover the transport cost. No shelves to reduced pressure and provide ample ventilation. This practice is detrimental to fruits. Fruits at the bottom suffer heat and pressure damage.

Another bad thing is the mixed mode of transport. Wholesalers never transport a single type of commodity. All types are arranged in a single compartment, which is the whole vehicle.  Goods producing large amount of ethylene are causing premature ripening of the others, and rot before reaching the market destination.

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.

Postharvest Practices of Some Crops in Our Local

This post is an excerpt from one of my masteral subject requirements. It deals with the existing postharvest practices of five major crops in our small barrio.

Patola

Patola are harvested when they are long and big but the wedges are still soft to touch. Harvesting is done any time of the day, rain or shine. The stalk is cleanly cut with a sharp bolo to prevent damage to vine. The preferred harvesting days are Fridays and Tuesdays to coincide with the next day market. This scheme causes some fruits to become over-mature and allow to grow as source of seeds.

If the commodity is not sold for 1 to 2 days, a small portion of the stalk is cut off to make it look fresh again.

For farms more than one kilometer from the road, hauling is done by horse. Patola are carefully arranged in two big metal baskets. These often result to breakage in which the severity depends on horse behavior and skill of horse handler.

Patola is a delicate commodity, easily broken when dropped or bent. To prevent damage, a group of 35 are wrapped together in banana bracts. It serves as a good protection but not good enough to resist fall or rough handling of transporters.  Non straights are packed separately and command a lower price.

Ampalaya (Bitter Gourd)

There are no exact criteria for maturity indices of bitter gourd. The following are the rough basis.  It should not be too big or too small depending on varieties. The wrinkle spaces should not be too wide and should not have any cracks.

They are packed in large polyethylene bags with a capacity of five to ten kilograms. Non straights and too small are packed separately and commands a lower price. Bag is closed only during transport to prevent accumulation and condensation of moisture.

Patani (Lima Beans)

Harvested when he beans are plumbed with the tip still soft to touch.  Those with skin damages are harvested but separated and checked if the beans inside are still fit for consumption. Four bean-pods are separated as it commands higher price. Two-bean pods and three-bean pods are sold for lower price. One-bean pods, over matured and those with skin damages are not sold. They are destined for home consumption.

Santunis

Harvested in its green ripe stage or the “manibalang” in Tagalog. Fruits with 10% or more yellow skin are left behind. They are likely to break and rot during transport, handling and storage. Harvesting time is done about past 9:00 am. Harvesting too early in the morning results in skin browning. The reason behind it is scientifically explained but very few farmers know it.

The harvested santunis are packed in sacks. Horses are used to transport it from farm to nearest road. Two sacks are secured on horse side using ropes and one on horseback, for a total of three sacks per transport.  This mode of transport causes an obvious damage to some fruits.

Santol

The fruit is harvested when it is yellow with slight traces of green color. The full ripeness of orange color has the best taste but the latter is preferable. It is still hard enough to resist transport vibrations and has longer shelf life for transport, storage and marketing.

Harvesting is done by climbing the tree and getting the fruits one by one with the use a small basket attached to a long bamboo pole. The harvester has a large bamboo basket (kaing) nearby as partial fruit container, attached to a long rope to facilitate the careful down transport.

harvesting santol fruits

Dropping fruits from tree during harvesting are still whole, looks good for market but are not included for packing and selling.  Some of the dropped fruits are overripe and almost all will have internal browning after few days.

The fruits are packed and transported in the same manner as santunis.  However, santol leaves are placed in sack bottom and top to serve as cushion.

Santol has relatively thick rind. It can be placed under the heat of sun for prolonged period without visible evidence of wilt.   The practice of leaving it under the heat of sun is common.

Mode of Transport

One mode of transportation was already mentioned above, horses which are trained to carry goods.  They are very common as many farms are far from road side and inaccessible to four-wheeled vehicles. Even if the farms are accessible, horses are still preferred during the rainy seasons.  These horses can cause some damage to commodities depending on their behavior. It can ruin the whole batch if gone wild and the owner is unable to control.

The cheapest way to transport good is by human means. Goods are packed in bayong or bamboo baskets and carry on shoulder or head. Carrying is usually done in a way most comfortable to carrier without taking consideration the effect on the commodity. Damage is likely.

Small time vehicular transport to market is fine but much harvest is jeopardized if done by the wholesale buyers. Mixed commodities are arranged in such a way the vehicle can carry the maximum commodity weight and not the way which is more conducive to harvest. Handlers (kargadors) are stepping on the goods during loading, transport and unloading.

Time of transport is usually done very early in the morning. Colder temperature is favorable but it is not the real reason for early transport. Buyers and sellers meet very early to avoid heavy traffic.

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.

Tips on Harvesting Dragon Fruit Flowers

The two dragon fruit flowers and one dragon fruit behind the scene. The two flowers are ready for harvest.

dragon fruit and dragon fruit flower

Here are some tips based on my very own experience.

The flower opens wide at night. Still wide open and up at early morning when morning dews are still visible on grasses, plants, fruits and flowers. It begin to close and droop down when sun shines. At this point, the flower can be harvested for whatever reason you have in mind. Hope it is for food purposes.

To harvest, get a clean sterilized knife. Wear a clean sterilized gloves. Cut the flower at point where it bends. Cut it carefully by rotating the cutter around the bent flower portion, leaving the filament behind.

It was a cloudy  day and  slight rain was pouring down when we harvested some. The outcome was bad. I guess it was a bad timing. All the base from which the flowers were cut off rotted. Perhaps, moist condition and unhygienic practice contaminated and caused it to rot.

Not touching the flower is fine. The fruit is going to develop to a large expensive commodity.

During sunny days, flowers could be left on plant to dry before gathering. However, it should be gathered fresh when intermittent rain is expected . The moist condition will make it moldy and unusable.

If you own a dragon fruit farm, chances are you already using the flowers and perfected the flower harvesting procedure. Sharing it is going to help those who never know it yet.

Marvin is the lead chocolate maker of Ben and Lyn Chocolate Inc. Has strong background in food research and development. Occasionally conducts training and lectures. Lecturer of Cocoa Foundation of the Philippines. Do coaching and consultancy services on his free time.