Two brands of green tea samples available in the market were used for the sensory evaluation along with the instant tea powder and green tea granules prepared from fresh tea leaves (Camellia sinensis). The main objective of this study was to evaluate the sensory scores of different tea samples using fuzzy logic and grade the samples as per their sensory qualities. Brew was prepared as per the standard procedure, and sensory evaluation was carried out by a trained panel of 16 judges. Fuzzy logic was used for ranking the samples and also to find out the preference of quality attributes of green tea drink in general. Green tea granules obtained from pressed leaf residue was ranked first followed by instant tea drink. Both the market samples were rated low in quality compared to the prepared tea samples. It was also concluded that in general, taste and flavor of green tea drink is considered to be the highly important quality attributes. The color and strength were reported under the category important. The strength and weakness of individual samples were also determined.

The plant Camellia sinensis yields a variety of white, green and black tea. Tea is one of the most widely consumed beverages in the world, next only to water for enjoyment and health. In general, green tea has been found to be superior to black tea in terms of health benefits. The major components of interest are the polyphenols which are responsible for the antioxidant and other health benefits of green tea. The major polyphenols in green tea are flavonoids. The four major flavonoids in green tea are the catechins, epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG) and epigallocatechin gallate (EGCG). Epigallocatechin gallate is viewed as the most significant active component. The processes used in the manufacture of black tea are known to decrease levels of the monometric catechins to a much greater extent than the less severe conditions applied to other teas. Much research is available depicting the health benefits of green tea for a wide variety of implications, including different types of cancer, heart disease, liver disease, etc. There is also a wide range of uses for green tea in diabetes, exercise enhancement, inflammatory bowel disease, skin disorders, hair loss, weight loss and iron overload. This paper will review the major health benefits of green tea, focusing on the catechins.

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The feasibility of measuring moisture content in green tea by Fourier transform near infrared (FTNIR) spectroscopic technique was investigated. Green tea granules samples with different moisture contents were scanned using FTNIR spectroscopy. The spectra were measured in diffused reflectance mode by keeping 4-5 g samples in small sample bottle. A partial least-square regression model was developed with vector normalization method in the near-infrared region (4,000-12,000 cm −1 or 800-2,500 nm). The developed model was validated using cross-validation technique. Maximum coefficient of determination (r 2 ) value of 0.997 was obtained for the calibration model developed. The developed method was used further for quantification of moisture content in fresh green tea samples, and the results were compared with other methods like gravimetric method and moisture analyzer. Results indicated that FTNIR spectroscopy could be used for rapid detection of moisture content in green tea granules without destruction of samples. The measurement will take only 5-10 s.

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