In this feature, we have focused on the deliciousness of rice, the staple food of the Japanese.
We hope that our readers will be able to experience the richness of modern food from a variety of perspectives. We explained the following:
· Development of a sensory lexicon for cooked rice and its application to sensory evaluation
· Visualization of the hardness and stickiness of cooked rice grains in the food chain
· Trends in breeding of high eating quality rice cultivars in Japan
· Genetic analysis for eating quality and grain quality by using genome sequencing in rice
· Development and branding of high temperature tolerant “Shindai Koshihikari”

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This paper introduces the development of a comprehensive sensory lexicon for improving the evaluation of cooked rice. Sensory evaluation is a method used to assess food quality based on human perception. It plays a key role in rice breeding, processing, distribution, and product development. In recent years, the variety of rice products has expanded significantly. These include high-quality cultivars, imported and blended rice, and cooked rice for commercial use such as refrigerated or frozen rice. This diversity requires a precise and/or efficient approach to sensory assessment.
Historically, rice sensory evaluation in Japan began with a standardized “taste test” developed in the 1960s. This method relied on judgment by experts across six broad categories, making consistent evaluation difficult without expert training. To address this challenge, the authors developed a sensory lexicon to reduce ambiguity and improve communication in sensory assessment.
Descriptive terms were collected from multiple sources. First, trained panelists evaluated 32 rice cultivars and listed sensory characteristics in four categories: appearance, aroma, taste/flavor, and texture. Next, additional terms were identified by experts who sampled cooked rice for commercial use. Finally, a literature review of academic and industry materials further supplemented the vocabulary. After consolidation of terms and defining each term by expert discussion, a lexicon of 120 terms was developed.
To confirm its usefulness, the lexicon was applied in sensory evaluation using the Check-All-That-Apply (CATA) method. Fifteen rice samples were evaluated by 13 untrained panelists. Even without specialized training, the panelists were able to identify sensory differences among samples using the lexicon. Correspondence analysis showed that the selected terms accurately reflected differences in rice type, cooking water ratio, and processing methods.
In addition to CATA, the lexicon is effective in supporting the rating method, where panelists score specific attributes. It improves scoring consistency and reduces the effort required to select and define evaluation items. Furthermore, referring to the lexicon during open-ended descriptions enhances the uniformity and clarity of language, supporting efficient product improvement and quality control.
The development of this lexicon marks a significant step toward reproducible and efficient sensory evaluation of cooked rice. It also promotes clearer communication of sensory quality among stakeholders in the rice industry.

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While the annual domestic rice consumption has fallen to less than half of its peak, the proportion of ready-made meals is on the rise, and the production of processed rice (aseptic packed cooked rice, frozen rice, retorted rice, dried rice, chilled rice, canned rice) continues to increase. As it is expected that the outsourcing of food will progress further in the future due to an increase in dual-income households, elderly people, and single people, it is necessary to build a food chain that can meet diverse actual demand and consumer needs for rice as well.
The authors have been developing a method for measuring the multiple physical properties of a single grain of cooked rice, aiming to utilize this method in the food chain. Specifically, using a low- and high-compression test (a compression test at a compression rate of 25% of the cooked rice grain thickness followed by a compression test at 90%) to measure the physical properties (hardness and stickiness) of a single grain of cooked rice separately for the surface and the whole grain, they have obtained knowledge so that this method can be applied to (1) detecting differences in physical properties between varieties, (2) estimating palatability and component ingredients from physical property values, (3) the relationship between nitrogen fertilization during cultivation and physical properties, and (4) understanding physical properties in the cold chain, such as chilling and freezing and thawing. In addition, by measuring a single grain of cooked rice, they have found that the physical properties of the surface layer of cooked rice grains are important as an evaluation index for palatability and quality.

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In Japan, where abundant rice production has persisted for many years, efforts to develop high eating quality rice cultivars have been promoted. To improve eating quality, the initial goal was to achieve a taste similar to “Koshihikari”. Using “Koshihikari” or its subsequent cultivars as parent strains, many high eating quality cultivars were developed and widely adopted. Additionally, breeding focused on traits such as reduced amylose content, was conducted to improve eating quality. As a result of these efforts, by around 2016, high eating quality rice cultivars had become widely available nationwide, and improvements in eating quality itself had reached a plateau. With the growing demand for high eating quality rice in the restaurant and food industry, there has been an increasing need for cultivars that combine high eating quality with high yields. To meet this demand, cultivars with high eating quality such as “Akidawara” and “Hoshijirushi”, which yield over 7 t/ha, have been developed, and further development of high-yielding cultivars with high eating quality is anticipated in the future. Furthermore, with recent warming trends, there is a growing need for cultivars with resistance to high temperature that exhibit minimal chalky grain formation under high temperature. In this context, promising cultivars with resistance to high temperature and good taste such as “Nijinokirameki” and “Shifukunominori” have been developed. In addition, genetic analysis using the indica rice cultivar “Habataki” identified the Apq1 gene, which enhances resistance to high temperature. It is expected that new genes resistant to high temperature will continue to be discovered through diverse research in the future.

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The whole genome sequence of the Japanese rice cultivar ‘Nipponbare’ were published by the International Rice Genome Sequencing Project (IRGSP) in December 2004. It is the first achievement of encoding the whole genome sequence in cereal crops and monocot plant species, and Japanese researchers greatly contributed to it. The ‘Nipponbare’ genome sequence has used as standard reference information for genome comparisons among rice cultivars and genetic analyses for important agronomic traits such as grain yield, disease resistance, stress tolerance and grain quality in rice. Next generation sequencing (NGS) technology is largely accelerating genetic analysis such as detection and identification of responsible genes involved in the control of the eating and cooking quality, and grain appearance quality traits. Our previous study detected more than 500 quantitative trait loci (QTLs) associated with eating and cooking quality traits by QTL analysis and genome wide association study (GWAS). We identified three responsible genes for the detected QTLs by carrying out additional genetic analysis. Several responsible genes associated with grain appearance quality have also been identified so far by other researchers. The recent significant results of these genetic studies have been used to develop DNA markers for selecting novel cultivars with superior agronomic traits in breeding programs. In the future, before starting development of novel cultivars, this genome prediction procedure could design gene combinations and genome compositions for desirable novel cultivars based on collected information for genome sequences and trait evaluation scores.

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Global warming in recent years has become an extremely serious environmental issue. It has also had a major impact on agriculture. Koshihikari is Japan's top elite rice variety in terms of good taste, and its cultivation accounts for more than 30% of the total rice cultivation area. However, due to the extreme heat and drought in the summer of 2023, the quality of Koshihikari brown rice in Niigata Prefecture, a rice-producing region, dropped significantly, with the ratio of grade 1 rice plummeting to single digits. Based on knowledge from basic research on the control of rice starch metabolism, we have developed a heat-tolerant Koshihikari mutant, Shindai Koshihikari (variety name: Koshihikari Niigata University NU1), using a culture mutation method. NU1 looks exactly like Koshihikari because it has the genes of Koshihikari itself, but it has been recognized to have the characteristics of deepening dormancy and strong high-temperature ripening. The high quality and good taste of NU1 have been evaluated by producers, retailers and general consumers, and sales performance has been progressing smoothly.
In branding the new rice variety “Shindai Koshihikari” developed by Niigata University, the brand value has been nurtured through value co-creation among three entities: producers, consumers, and BIT (Brand Incubation Third Party), utilizing knowledge of marketing research (various parties can be listed for each brand, such as distributors, retailers, mass media, local governments, and certification agencies). By promoting initiatives that utilize the integrated knowledge of natural science and social science, we hope that “Shindai Koshihikari” will be able to fully realize its potential into the future and grow into a brand that will continue to be loved for many years, just like the great brand rice “Koshihikari”.

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This report compares quality assurance of foods, including processed ones, with that of engineering products, especially drugs. The most important priority for quality assurance of foods is to ensure safety. Fundamentally, foods are natural in origin. Therefore, they are multicomponent products. The safety of foods basically depends on their history of use as food. This suggests that a compound within a food product is assumed to be safe up to its historically used content level unless there is a known risk of mutual reaction. However, the safety of a compound which has no history of use in food cannot be assured without toxicological tests. Unknown compounds may be dangerous. There are three important steps in quality control of food products, namely product design, process control and testing. Normally, food manufacturers control the presence of risky compounds such as agrochemicals, heavy metals and micotoxins by these steps. They should also consider how to protect against contamination by unknown compounds using these steps, when feasible.

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Food additives have greatly contributed to the manufacturing, quality preservation, and diversification of processed foods. Furthermore, provided they are used appropriately and within standard limits, official records show no health damage caused by them over the past 20 years. Despite this safety record, food additives consistently rank high in consumer surveys regarding food safety concerns. Recently, the idea that a “cocktail effect” from multiple food additives in “ultra-processed foods” causes health issues has gained traction. This consumer anxiety, persistent even without actual reported harm, cannot be explained by a single factor. It is believed to result from a complex interplay of major turning points in human history and shifts in social structure. These include: the Cognitive Revolution, which brought humanity the capacity for abstract thought and belief in fictions; the Neolithic Revolution, which enabled agriculture and food storage; the Scientific Revolution, which introduced new risks like food additives and pesticides; and the Information Revolution, which, while advancing the democratization of information, also provided fertile ground for the easy spread of misinformation. These factors interact, creating a deep-seated consumer unease that scientific safety evaluations alone cannot easily dispel. Consequently, countermeasures must also be multifaceted. This pattern of concern is also common for issues like pesticide residues, genetically modified organisms, and per- and polyfluoroalkyl substances (PFAS).

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Maca is a plant of the Brassicaceae family that is native to the highlands of the central Andes Mountains in South America. This region is a harsh environment where most plants cannot grow, but maca is an extremely strong plant that can thrive. As the maca plant grows, the above-ground part of the plant grows, forming an underground tuberous root measuring 4 to 8 cm. This part is used raw or dried for food and medicinal purposes. As an edible product, it contains a lot of protein, which is a general nutritional ingredient, and its nutritional value is of high quality, comparable to eggs and milk. It is also rich in inorganic components. Among the indigenous peoples who do not have a written language, the medicinal effects of maca have been passed down, such as improving male sexual function, improving menopausal symptoms, protecting the nerves and preventing dementia, protecting against ultraviolet rays, preventing diabetes, improving learning function, improving motor function, being anti-fatigue, being an antioxidant, and preventing prostate hyperplasia. Currently, these traditional medicinal effects are being verified through animal experiments and human clinical trials. Furthermore, many functional components such as glucosinolates, macamides, macaenes, thiohydantoins, alkaloids, sterols, and flavonoids have been detected as factors contributing to these functions.

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Burdock (Arctium lappa L., English name edible burdock) is a biennial plant of the Asteraceae family, believed to have originated in Central Asia. In Japan, burdock developed as a vegetable and is a valuable crop that is presented as a sacred offering at festivals in the Kinki region. Burdock achenes were introduced from China during the Heian period for medicinal purposes. At the end of the Heian period, it appeared in banquet dishes with dried foods or shaved foods, and in the Kamakura period, it was cultivated and used as a tribute crop. In the Edo period, famous products such as “Yawata Gobo”, “Oura Gobo”, and “Horikawa Gobo” appeared. The representative variety of burdock in modern times is “Takinogawa”, and representative burdock dishes for special occasions in both the east and west are “kinpira gobo” and “tataki gobo”. Regarding the medicinal properties and nutrition of burdock, the Compendium of Materia Medica states that the roots are nutritious as a vegetable and the achenes are medicinal, and it was used as a folk remedy from the Taisho to early Showa periods. According to recent research reports, burdock has pharmacological properties including antibacterial, hypoglycemic and antitumor properties, and furthermore, roasted burdock maintains high antioxidant properties, and burdock tea made from roasted burdock suppresses ammonia (products of decay, etc.) in the intestines, making it a popular functional food in modern times.

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