Identifying objective characteristics that predict clusters produced by sensory attributes in cooked rice

From eight samples of raw-milled, 10 samples of parboiled and 2 samples of canned rice, appearance, texture and flavour were determined sensorily and related to instrumental parameters and clusters of different types of rice having common sensory perceptions were identified. The physico-chemical cha racteristics, enthalpy of amylose-lipid complex I, protein content, length of raw grain, elastic recovery, water uptake and the viscoelastic index, va ried widely between rice samples. The most discriminatory sensory attribute s were appearance and texture characteristics such as 'brown', 'elastic', ' long', 'firm' and 'shiny'. The instrumental measurements were highly correl ated with sensory parameters. Parboiled rice samples, characterised by a br own colour, an elastic-firm smooth texture and a broth flavour, were differ ent from the raw-milled rice samples described as 'juicy', 'melting', 'shin y', 'aggregated and swollen grains', 'starch and milk' flavour. Canned rice samples were distinguished by a 'jute and earth' flavour, 'bitterness' and the presence of 'foreign matter'. Five clusters of types of rice could be distinguished which were characterised by a soft texture for the first, by a sticky-pasty texture for the second, by a brioche flavour and medium inte nsity characteristics of sticky and melting texture for the third, by the l ength of grain and a slight crunchy texture for the fourth, and by the firm ness and elasticity for the last cluster. Five instrumental determined char acteristics, enthalpy of amylose-lipid complex I, thickness of cooked grain , water uptake, browness index and protein content classed each rice into o ne of these 5 clusters with an error of 4%.