Japanese Rice Producers' Shift from High Yield to High Palatability and Quality
—Characteristics of Highly Palatable Rice—

Abstract

In 1962, Japanese people consumed 118.3kg year⁻¹ person^-1 of rice. However, after decreasing continuously for four decades, consumption was only 61.9kg year⁻¹ person^-1 in 2003. Since the 1980s, Japanese people have preferred highly palatable, high-quality rice products instead of quantity. We investigated some palatability properties and characteristics of rice products in different regions around Japan. Thicker brown rice and heavier brown rice were thought to have high palatability and quality, traits that have been associated with low percentages of protein and/or amylose. However, our results showed that these two characteristics were not related to palatability in the case of thicker brown rice. The surface and the interior ultrastructure of cooked rice also affect palatability. In highly palatable cooked rice, thin fibrous and mesh-like surface structures are well developed; mesh-like and spongy structures are also detectable inside. In contrast, the surface of cooked rice of low-palatability is covered with gel-like structures and has less-developed fibrous and mesh-like structures; fewer mesh-like structures are detectable inside. Different cultivars and environmental conditions also affect palatability and quality. The major conditions are the effects of high or low temperature, water status, and strong rain or wind during the ripening period. Currently we are analyzing the ripening process and how environmental conditions during ripening affect rice palatability and quality.