How do you keep an asparagus fresh and crisp in the refrigerator for seven days? You put it to sleep.
Hitachi has just released a new refrigerator in Japan that prolongs the storage life of vegetables through the natural gases it discharges. By filling the vegetable compartment at the bottom of the fridge with carbon dioxide, the respiration of the vegetables is reduced, resulting in a slower decay process. Hitachi calls it “sleep preservation.”
The secret to the new technology is a platinum catalyst that is placed inside the handle of the vegetable tray. When odor components and ethylene gas emitted from vegetables and fruit come in touch with the catalyst, they are broken down into water molecules and carbon dioxide.
The platinum catalyst requires no electricity. Hitachi made use of a technology recently developed at Hokkaido University. The capacity of the platinum is 30 times higher than the photocatalysts that Hitachi used in previous models.
Until now, Hitachi used a light-emitting diode, or LED, source to project light onto the photocatalyst to enhance the decomposing process. Since the device was placed on just one side of the vegetable drawer, the capacity to break down gases was limited. “You had to keep your vegetables in the lower left hand side of the vegetable drawer to really keep them fresh,” said a Hitachi spokesman.
Due to the more powerful platinum catalyst, the entire vegetable compartment — called the Aero-care Vege Zone — can be packed with carbon dioxide.
Vegetables continue to breathe after they are harvested. They consume their own nutrients to stay alive. When surrounded by carbon dioxide, the respiration slows down, as does the consumption of nutrients. According to Hitachi scientists, the vitamin C left in an asparagus after seven days jumped from an average 57% in older fridges to 67% in the new “sleep” fridges. The polyphenol left in a Boston lettuce improved from 85% to 95%.
This is the first time a platinum catalyst has been used inside a household refrigerator. The largest R-X7300F type, with an internal cubic volume of 730 liters, is sold for 470,580 yen ($3,888) at Japanese electronics retailer Bic Camera’s online store. The fridge comes in 12 sizes.
The idea of using platinum for a fridge emerged when a Hitachi employee read a news article about a new discovery at Hokkaido University. A team led by professor Atsushi Fukuoka had found a way to preserve fruit and flowers by removing the ethylene gas that they emitted. Hitachi called the university to inquire if the technology could be applied to a fridge.