Knowing postharvest losses in onion, tomato and mango value chains

by Admin-Phmp

Text and Photos by Henrylito D. Tacio

What do onion, tomato, and mango have one thing in common?

Onion and tomato are among the most important spices used by Filipinos to perk up somewhat drab dishes. Both can also be made into a fresh salad. Mango, on the other hand, is one of the three fruits usually served as dessert in “eat all you can” eateries; the two other fruits are watermelon and papaya.

As they are popular among consumers, most Filipino farmers grow them. But the sad thing is that they usually deteriorate days or a week after they are harvested. So much so that the Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) conducted a study on postharvest losses along the value chains of the three crops.

The results of the study, “Analysis of Fruit and Vegetable Value Chains in the Philippines,” which the Manila-based Asian Development Bank (ADB) funded, was presented at a recent virtual national policy forum jointly organized by SEARCA and SyCip Gorres Velayo & Company (SGV & Co.).

Onion, tomato, and mango are staples in the Filipino cuisine and should be given significant attention and funding to improve postharvest handling efficiency, said Evelyn Laviña, the Department of Agriculture (DA) Undersecretary for High-Value Crops and Rural Credit.

Dr. Marlo Rankin and Dr. Flordeliza Lantican, agricultural value chain and market expert and agricultural value chain and market specialist, respectively, presented the study results, which focused on the postharvest losses quantified along the value chain of the three commodities.

In a SEARCA news release, the study revealed that mango produced in Iloilo and traded in Manila showed the highest postharvest losses at 33.89%. Pangasinan-Manila route ranked second at 30.85%, and Guimaras-Negros Occidental route ranked third at 19.02%.

Notably, a Guimaras mango corporation that observes good agricultural practices (GAP) posted the lowest postharvest losses at 11% in shipping fruits to Manila.

Postharvest losses in terms of volume and value indicate a significant reduction in marketable supply and income of key actors in the mango supply chain.

Pangasinan registered the highest volume at 31,581 tons and value at P1.595 million of postharvest losses when mango is traded in Manila because it has higher mango production than other provinces. Iloilo, with the same destination, came second with volume and value of postharvest losses at 8,682 tons and P434 million, respectively.

Meanwhile, the total postharvest loss of freshly harvested onions from the farm in Bongabon, Nueva Ecija, to the final market in Divisoria, Manila, was 45.06%. The estimated volume of postharvest losses for red onion reached 48,891 tons and a value close to P1.96 billion.

Postharvest losses for the cold-stored onion chain with the same route totaled 63.90%, with estimated volume and value lost at 69,333 tons and nearly 4.01 billion, respectively.

On the other hand, freshly harvested tomatoes produced in Nueva Ecija and traded in Manila incurred a postharvest loss of 10.94%. The volume of postharvest losses reached 1,930 tons with a value of P47 million.

The total postharvest loss of freshly harvested tomatoes from the farm in Bukidnon, Northern Mindanao, to the final market in Manila was much higher at 24.14% due to longer travel duration. This equates to an estimated volume of postharvest losses of 41,125 tons and value close to P180 million.

Among the key recommendations in reducing postharvest losses for the three commodities include investing in cold storage and packing facilities, providing delivery vehicles to facilitate the transport of goods, developing online trading or digital marketing in partnership with the private sector, increasing access to credit and insurance, and strengthening extension services at the grassroots level.

Dr. Takeshi Ueda, Principle Natural Resources and Agriculture Specialist at ADB’s Southeast Asia Department, said the study is relevant to the directions of both DA and ADB, which are agricultural diversification, industrialization, modernization, and commercialization.

In his message delivered by SEARCA Deputy Director Joselito G. Florendo, SEARCA Director Glenn B. Gregorio stressed that the pandemic enabled people to realize the significance of the whole value chain process because the food supply is not limited only to production.

Dr. Gregorio also pointed out that onion, tomato, mango, and other high-value crops should be upscaled and the need to invest in them to ensure that the Philippines will have “a future-proof agriculture sector.”

He also stressed that SEARCA values research projects focused on agricultural development as they contribute to the center’s thrust of accelerating transformation through agricultural innovation, or what he called as ATTAIN.

Aside from being used in dishes, onion, tomato, and mango are also very popular due to the nutrients and vitamins they contain.

Tomato is considered one of the richest of all foods in vitamins. It is very rich in all three important vitamins like A, B, and C, while most vegetables are deficient in one or more. Vitamin A plays an important role in vision, fighting infection and bacteria, maintaining skin and body linings, bone and body growth, reproduction, and normal cell development.

The B vitamins are very important to maintain good health. A deficiency of Vitamin B6 can raise a person’s risk of heart disease. Evidence also indicates that about 40 percent of heart attacks and strokes may be caused by a deficiency of folic acid, another important B vitamin.

Vitamin C is needed by the body to form collagen and fiber for teeth, bone, cartilage, connective tissue, skin, and capillary walls. It helps in fighting bacterial infections. It may also protect against declining mental ability and stroke. Vitamin C of tomatoes is not destroyed by heat, and therefore they are practically valuable for all sorts of stomach and liver troubles.

“Onions are super-healthy,” said Victoria Jarzabkowski, a nutritionist with the Fitness Institute of Texas at the University of Texas at Austin. “They are excellent sources of vitamin C, sulphuric compounds, flavonoids and phytochemicals.”

“I like to recommend eating onions because they add flavor without salt and sugar,” Jarzabkowski added. Onions are low in calories (45 per serving), very low in sodium, and contain no fat or cholesterol. Furthermore, onions contain fiber and folic acid, a B vitamin that helps the body make healthy new cells.

“The flavonoids in onion tend to be more concentrated in the outer layers of the flesh,” the website of the World’s Healthiest Foods ( claims. To maximize its health benefits, “peel off as little of the fleshy, edible portion as possible when removing the onion’s outermost paper layer.” Even a small amount of “overpeeling” can result in unwanted loss of flavonoids.

The total polyphenol content of onions is much higher than most people expect. Polyphenols are one of the largest categories of phytonutrients in food. “The total polyphenol content of onion is not only higher than its fellow allium vegetables, garlic and leeks, but also higher than tomatoes, carrots, and red bell pepper,” the website reports.

The particularly valuable flavonoid in onions is quercetin, which acts as an antioxidant. Although the average onion is likely to contain less than 100 milligrams of quercetin, some onions do provide this amount. “When onions are simmered to make soup, their quercetin does not get degraded,” reports the website. “It simply gets transferred into the water part of the soup. By using a low-heat method for preparing onion soup, you can preserve the health benefits of onion that are associated with this key flavonoid.”

Mango is a vitamin powerhouse. “One small mango provides a quarter of your recommended daily allowance for vitamin C, nearly two thirds of your daily quota for vitamin A, good amounts of vitamin E and fiber. They also contain vitamin K, phosphorus and magnesium. Mangoes are particularly rich in potassium,” wrote Fiona Wilkinson, author of “Health Benefits of Mangoes.”

Mango is also considered a ‘high volume’ food; it means you get a lot of food for a relatively small amount of calories. “One mango contains around 135 calories,” wrote Wilkinson. “However, they are quite high in natural sugar with one mango containing around 30 grams.”

Mango, being high in calories and carbohydrates, is good for those who are trying to gain weight. As it is high in iron, mango is said to be very good for pregnant women as well as for people suffering from anemia.

“Mango has three times the vitamin C of a single orange or apple and important minerals essential to prevent cancer and other diseases,” said Dr. Martin Hirte, a German health food researcher, and pediatrician.

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