External preference mapping and quality assessment of Jasmine rice.

摘要

Although Asian-Americans consume large amounts of Jasmine rice, they discriminate against its quality. In the past decades, domestic aromatic rice has accounted for less than 1% of the aromatic rice sold in the US. It is imperative to develop a better understanding of Jasmine rice's quality traits, driving its acceptance by consumers, and to identify the shortfalls of domestically grown Jasmine rice. Thus, objectives were (1) to evaluate the Asian-American consumers' acceptance of three domestic and twelve imported Jasmine rice samples via sensory external preference mapping, (2) to document major quality differences between the samples, and (3) to correlate consumer acceptance to analytical measurements of appearance, flavor, texture, and develop a set of instrumental tools designed to improve the quality of domestically grown Jasmine rice. One hundred and five Asian-Americans participated in a home-use test. A trained sensory panel characterized visual, flavor and texture attributes of Jasmine rice samples. Important factors determining overall acceptance by these consumers were aroma and flavor acceptances, and intensities of color, flavor, aroma, stickiness, and hardness of the samples. Rice kernels, flours, and starches were characterized for physical, chemical, pasting, and thermal properties. Amylose content, gel type, hardness and stickiness ratio, surface fat, protein, and pasting properties were found to be the key determinations that pointed out the weakness and separated domestic from imported Jasmine rice. An instrumental double compression test in combination with spectral stress strain analysis was used to predict the acceptance of rice hardness and stickiness, and other specific sensory attributes. Sensory quality was overall best predicted by test performed at 10 min post cooking. Jasmine rice volatiles were identified using solid-phase microextraction in combination with gas chromatography-mass spectrometry, and selective-ion monitoring. Model statistics of the consumer acceptance, using the peak areas of volatiles as predictors, were comparable with those reported when the descriptive attributes were used as predictors. Gas chromatography was found to be a viable method for predicting flavor acceptance.