To explore the quality characteristics of Laoshan ancient tree sun-dried green tea in Malipo and analyze the internal correlations among physicochemical indexes, color, electronic sensory properties and artificial sensory evaluation.
The content of water extract, tea polyphenols, free amino acids, caffeine and catechins were determined in the sun-dried green tea water of ancient trees on the Laoshan of Malipo. A colorimeter, electronic nose and electronic tongue were employed to quantitatively characterize the color, aroma and taste of tea infusions,respectively followed by comprehensive analysis combined with artificial sensory evaluation.
The content of water extract, tea polyphenols and catechins in all samples were higher than the national standard GB/T 14456.2—2018 Green tea Part 2: Dayezhong green tea. The absolute values of the coefficients of variation for the polyphenol-amino acid ratio, a* and sour, astringent, bitter and salty taste indicators all exceeded 30%. Principal component analysis extracted 5 principal components, which could be integrated into 3 core evaluation dimensions (physical and chemical constituents-taste, physical and chemical constituents-tea soup color and volatile aroma) and 2 secondary auxiliary dimensions, enabling effective quality discrimination of tea samples. Significantly positive correlations were found between free amino acids and sweetness, L* and infusion color score, a* and astringency as well as b* and bitterness(P<0.05). Partial least squares regression analysis showed that the response values of b* and W1C, W1W, W3S,astringency, bitter aftertaste, saltiness and sweetness made significant contributions to the artificial sensory score.
Laoshan ancient tree sun-dried green tea in Malipo exhibits excellent overall quality. The polyphenol-amino acid ratio, a* as well as sour, astringent, bitter and salty taste indicators are the core factors driving quality differences. Tea quality is synergistically determined by water-soluble taste substances, color and aroma components, and precise quality evaluation can be achieved through principal component analysis.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |