Flavor lexicon for sensory descriptive profiling of different rice types.

Rice flavor is a significant factor in determining quality and consumer acceptability as exemplified by scented rice, which is highly favored and commands a price premium. Sensory descriptive analysis has primarily been performed to assess rice flavor characteristics, but these studies feature only a limited lexicon for characterizing specific flavors or the range of flavor types is limited. This study was undertaken to establish a descriptive lexicon with reference standards for describing the flavor properties of a broad spectrum of rice types and use the developed lexicon to characterize which sensory attributes are most important in rice flavor quality. A rice flavor lexicon consisting of 24 descriptive notes was developed and expanded by 8 trained sensory panelists to characterize the flavor of cooked rice differing in terms of forms, types, and specialty (n = 36). Of these 24 descriptive terms, 19 were aromatic notes and 5 were fundamental tastes and oral feeling factors. Eighteen aromatic terms were significantly present in most rice samples whereas some descriptors exhibited unique characteristics of a specific-rice type. Subsequent multivariate analysis indicated that 18 descriptive terms were required to fully understand the characteristics of rice flavor in greater details. This lexicon covered a wider range of rice samples than in the previous studies and will facilitate targeting the characteristic notes important to rice processors as well as producers.

Relating sensory descriptors to volatile components in flavor of specialty rice types.

Flavor is a key factor contributing to consumer acceptance and repeat purchase of rice. Plant breeders focus on production yield and ignoring quality traits because there are no readily useable tools to evaluate quality. A systematic approach is needed for rice breeders to select rice with favorable flavor traits. Descriptive sensory analysis combined with chemical analysis provided an insight of sensory significance to interpret chemical data for a better understanding approach of rice flavor. This study was aimed to develop prediction models for sensory descriptors based on the volatile components derived from the gas chromatography-olfactometry (GC-O) that would be useful to help select rice cultivars containing a satisfactory flavor to produce improved quality in rice breeding programs. Thirteen Korean specialty rice samples were evaluated for their flavor components using descriptive analysis and GC-O. Nineteen aroma attributes in cooked specialty rice samples were evaluated by 8 trained panelists and statistically correlated to the concentration of aroma-active compounds derived from GC-O analysis. Prediction models were developed for most aroma descriptors including popcorn, cooked grain, starchy, woody, smoky, grain, corn, hay-like, barny, rancid, waxy, earthy, and sweet aroma using stepwise multiple linear regression. (E,E)-2, 4-decadienal, naphthalene, guaiacol, (E)-2-hexenal, 2-acetyl-1-pyrroline, 2-heptanone contributed most to these sensory attributes. These models help provide a quantitative link between sensory characteristics of commercial rice samples and aroma volatile components desirable in developing a rapid analytical method for use by rice breeders to screen progeny for superior flavor quality.