The objective of this study was to quantify the mastication effort for cooked rice. We analyzed mastication patterns while normal subjects ate a spoonful of cooked rice that had been prepared by cooking with different amounts of water (1.5, 2.0, 3.0, and 4.0 times the water to rice weight). The rice samples were served with the same weight, same volume and same solid content, and electromyography (EMG) of the masticatory muscles was measured. The texture of the four cooked rice samples was instrumentally analyzed by the two-bite method. The number of chews, masticatory time, and jaw-closing muscle activities per chew evaluated by EMG were higher in the rice sample cooked with least water, which exhibited a high firmness value in the instrumental test. Rice cooked with 4.0 times the amount of water exhibited the longest jaw-opening duration, which was related to the adhesiveness value in the instrumental test. The ratio of jaw-opening muscle activity to the preceding jaw-closing muscle activity was lower for the rice containing least water, this corresponding to the area ratio (balance degree) in the instrumental test. Softer rice containing more water reduced the total mastication effort until swallowing because it required a shorter mastication time. It was not difficult for the softer rice with high density to be ingested in greater weight, decreasing the mastication effort for a certain amount.

The difficulty in masticating and swallowing rice cake was quantified. Healthy subjects ate pieces of rice cake (9 g and 3 g) and a modified product (9 g). We used electromyography to measure the activity of the jaw-closing and -opening muscles during chewing, as well as the suprahyoid muscle activity, laryngeal movement, and sound during swallowing. The smaller the rice cake, the shorter the mastication time, the fewer the number of chews, and the less the jaw-closing muscle activity. A modified rice cake product (9 g) was consumed with less mastication effort than the standard rice cake (9 g) and with the same effort as the standard (3 g). Both the sample amount and texture influenced mastication, although neither factor caused a significant difference in swallowing characteristics. These observations suggest that swallowing was induced when the bolus properties became suitable for swallowing, as healthy subjects could adjust their mastication technique according to the food amount and texture.

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A sensory lexicon was developed for describing the characteristics of brewed coffee. A panel consisting of six untrained coffee professionals and four experienced trained coffee tasters generated 377 expressions in a sensory evaluation of 24 coffee samples selected from commercial 52 coffee types. Of these expressions, 127 terms (seven for appearance, 61 for aroma, 23 for taste/flavor, eight for mouthfeel and 28 for overall impression) were selected for the lexicon. Twelve selected assessors who did not have any experiences in coffee tasting or any special knowledge about coffee validated the list. Rec-8 Corresponding Journal of Sensory Studies 25 (2010) 917-939. © 2010 Wiley Periodicals, Inc. 917ognition of each term by consumers and untrained coffee professionals was then investigated, and a 50% recognition criterion was used as the minimum level for the vocabulary of each group. Out of 127 terms, 31 and 60 terms were regarded as suitable for the consumer and untrained coffee professionals, respectively. The data obtained in this study are relevant for description of products in sales, as material for consumer education in workshops on coffee, and as a preliminary source of descriptors for a sensory evaluation in product development in Japan. PRACTICAL APPLICATIONSJapan is the fourth largest importer of coffee in the world. Although some sensory lexicons of brewed coffee were developed internationally, these coffee lexicons contribute little to a precise description of coffee in Japan because sensory descriptors are affected by culture and language. This research provides a sensory lexicon consisting of 127 terms for describing the characteristics of brewed coffee in Japan and tests the recognition of each term by Japanese consumers. The lexicon developed in this study can be used as a preliminary source of descriptors for a sensory evaluation during product development and for a questionnaire during market research in Japan. In addition, it can be useful in describing sensory characteristics of coffee in a sales situation and in workshops on coffee for consumers. SENSORY LEXICON OF BREWED COFFEE IN JAPAN SENSORY LEXICON OF BREWED COFFEE IN JAPAN