AW Kinki (president: Hiroaki Yamamoto) is dealing with the sales of carbon dioxide to remove astringency of persimmon in Wakayama Prefecture which is No. 1 producer of persimmon and Nara Prefecture which is No. 2 of the same over the country. The season of astringency removal is between the end of August and the end of October every year. In this season AW Kinki expects to deliver 360 to 370 tons exceeding the result of last year.

Astringency of persimmon originates in a substance called tannin, which makes us feel astringency when it is melted into water, but it does not easily melt into water when combined with acetaldehyde instead of water, making us feel no astringency. For this reason, carbon dioxide, dry ice or alcohol which produces acetaldehyde has been utilized as a means to remove astringency.

Each of them is an old technique having been used practically since more than 30 years, but dry ice has difficulties in quantitative adjustment as frostbite may be caused by a direct contact with fruit, while alcohol has a disadvantage to help softening to cause a shorter life expectancy. In many cases, therefore, carbon dioxide is popularly used now.

AW Kinki is also placing a focus on supply CO2 to vegetable factories. Although many cases are for a monthly consumption ranging from 3 to 4 tons to grow mainly tomato or leaf vegetables, there also is a case of plant having installed a 10-ton CE. President Hiroaki Yamamoto is so enthusiastic to say, “Wakayama Prefecture is an agricultural kingdom producing not only persimmons, but also the output of orange, plum and peach is at a top level. We would like to keep a stable supply in close contact with local requirements for a higher growth in the agricultural field in our joint pursuit of synergy with the farming companies.”