73G-21 |
Aroma quality analysis of Taiwan local tea by sensory evaluation and electronic nose |
A. S. M. OU and L. S. Chen. Dept. of Food Science, National Chung Hsing University, 250 Kuokuang Road, Taichung, 402, Taiwan Physicochemical or instrumental analysis usually is classified as an objective method for food analysis while sensory analysis is thought more subjective. However, the aroma of food is a sensory term expressed by human senses, the physicochemical or instrumental analysis can be used to replace the sensory test only under the situation as a high correlation between sensory with physicochemical or instrumental analysis exists. The purpose of this study is to investigate the ability of sensory evaluation and electronic nose to differentiate the various tea produced in Taiwan. Totally 58 Taiwan local winter-season tea samples with different tea type, elevation of production area, degree of roasting and price were selected as experimental materials. The aroma qualities of these tea samples were evaluated by 6 well-trained panelists with 12 descriptors. The volatiles from the headspace of these tea samples incubated at 50 ¢J for 10 min were sensed by an electronic nose (Alpha MOS, France) with 12 metal oxide sensors. From the results of the principal component analysis, the first two components could explain the sample variance up to 73% and 75% from sensory and electronic nose data, respectively. Significant correlation was found between these two methods describing the aroma of tea samples. Using 14 unknown tea samples to investigate the classification capability of these two methods, it is found that the electronic nose was the same or even better than the sensory panel in term of the elevation of production area, degree of roasting, tea type and price of Taiwan local tea. The results clearly indicate the potential of the electronic nose to predict sensory attributes of Taiwan local tea and its applicability to discriminate the different types of tea produced in Taiwan.
Session 73G, Sensory Evaluation
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