University of Miyazaki Prof. Masahito Suiko explains the team’s achievements using a projector in Miyazaki.
Masahito Suiko, professor at University of Miyazaki’s Faculty of Agriculture in Miyazaki, and Miyazaki JA Food Research & Development Inc. have scientifically proven through a joint research that kumquat peel can activate natural killer (NK) cells, a component of the innate immune system.
NK cells defend the body from infection by recognizing and destroying such cells as tumor cells and virus-infected cells. The research team said they believe beta-cryptoxanthin, a type of carotenoid contained in kumquat peel, has the effect of activating NK cells.
The results of the research are expected to appear in the May issue of Bioscience, Biotechnology, and Biochemistry, an English magazine published by Japan Society for Bioscience, Biotechnology, and Agrochemistry.
The team has been conducting research since 2011 to discover unfound functional effects of the citrus fruit, using the so-called high-throughput food functionality evaluation method, developed by Suiko in 2008 and whose patent is held by the university.
They gave frozen powdered kumquat peel for a week to mice without stress and those with stress and compared the results. They found that NK cells were activated even for mice with stress.
A single dose of powdered kumquat peel given to the mice is equivalent to one kumquat for humans. The team plans to verify the effect on human beings.
Miyazaki is the nation’s largest producer of kumquats. Although peel of other citrus fruits produced in the prefecture, such as Daidai bitter oranges and Hyuganatsu oranges, are also rich in beta-cryptoxanchin, they chose to conduct the research with kumquats because they can be eaten completely including peel.
An official of Miyazaki JA Food Research & Development Inc. said they succeeded in obtaining results in a research area where it is relatively difficult to produce results. “We hope our achievement will lead to an increase in consumption of kumquats,” the official said.
“Because there are many food items in Miyazaki with various nutritious components, we are aiming at conducting research on food ingredients that enhance recovery from physical fatigue, which will be useful for athletes who come to Miyazaki for training camps,” Suiko said.
(March 24, 2015)