A Saga company has found an eco-friendly way to keep fruits, vegetables and flowers fresher for longer periods using abandoned local bamboo plants and undervalued tea leaves.
Venture firm Tanka Co., located in central Saga, developed the “Tanka Fresh F&V” packs, which are designed to absorb ethylene gas, the main factor in the ripening of fruits and vegetables.
The product’s main components are fine bamboo charcoal ash and a high concentration of catechin extract from third-picked, lesser-quality harvests of green tea leaves.
In developing the product, the company focused on neglected bamboo groves, which contribute to the dilapidation and erosion of forests. It also decided to use such tea leaves, as they are often left unpicked due to their cheap market price.
Tanka finished developing the product in February after more than a year, and then applied for a patent.
In June, the company tested the freshness agent on sweet potatoes exported from Japan to Hong Kong by ship. The proportion of crops that spoiled after a week in transport was reduced from 10 percent or more to nearly zero, according to Tanka.
Tanka was established in March 2012 to effectively use bamboo, a renewable biomass resource, and thereby reduce the number of abandoned bamboo groves.
The company gathers felled bamboo from areas around the prefecture and cuts them into narrow strips, then reduces them to ash at a plant in Kashima in the prefecture.
Sales channels would be limited to such places as farm stands if the charcoal was only sold on its own. So, Tanka President Yasuo Irie decided to develop a freshness enhancer that uses the bamboo charcoal, to give it added value.
The company struggled to discover what to blend with the ash before developing the product.
“Our focus was on what to mix with bamboo charcoal,” said Irie, 65. “We made continual efforts to discover the ideal mix through trial and error.”
The company eventually set its sights on catechin extract. While bamboo charcoal powder alone can absorb gases, high concentrations of catechin enhance this quality, Tanka said.
At first, the company crushed tea leaves into a fine powder and mixed it with the charcoal powder, but the quality of the mixture as a freshness enhancer was insufficient. Tanka learned to extract high concentrations of catechin from the tea leaves with technical assistance from the prefecture’s tea-experimentation facility in Ureshino. The company uses leaves grown in Ureshino as a raw material.
A competing freshness agent that uses natural zeolite and potassium permanganate to absorb ethylene gas has the lion’s share of the global market.
However, Irie said such enhancers are not as safe as those that use plants.
“(A freshness enhancer) made from natural materials eases consumer concerns (concerning food safety), considering they are likely to touch and swallow the product’s ingredients,” Irie added.
One pouch of the freshness-enhancing agent, sufficient for a 5-kilogram box of fruits and vegetables, is priced at 80 yen (70 cents). A pouch for a 10-kg box is 150 yen.