不同等级金牡丹乌龙茶品质和矿质元素差异分析

以不同等级金牡丹乌龙茶为试材，测定了不同等级金牡丹乌龙茶的感官审评得分、品质指标（茶多酚、咖啡碱、8种儿茶素、可溶性糖、游离氨基酸、茶氨酸、水浸出物和总黄酮）和8种矿质元素含量。等级越高的金牡丹乌龙茶水浸出物含量越高，特等奖水浸出物含量比一等奖和优质奖分别高1.07%和1.75%，且差异均达到显著水平（P<0.05）。咖啡碱、可溶性糖和总黄酮含量均为低等级显著高于高等级（P<0.05）。三个等级的茶多酚含量之间没有显著差异（P>0.05）。特等奖的酚氨比要显著低于一等奖和优质奖（P<0.05）。优质奖的茶氨酸含量要显著低于特等奖和一等奖（P<0.05）。线性回归分析表明，游离氨基酸和总黄酮与审评得分呈显著线性负相关（P<0.05），可溶性糖与审评得分呈极显著线性负相关（P<0.01），而水浸出物与审评得分呈极显著线性正相关（P<0.01）。不同等级金牡丹乌龙茶除Mn和Fe外，大多数矿质元素之间不存在显著差异（P>0.05）。限制性主坐标分析表明，品质指标结合限制性主坐标分析可以很好的区分金牡丹乌龙茶等级差异，R值达1.00。但矿质元素结合限制性主坐标分析并不能很好的区分不同等级金牡丹乌龙茶的品质差异。研究结果为金牡丹乌龙茶品质鉴定提供相关参考依据。

Analysis on the Difference of Quality and Mineral Elements Among Jinmudan Oolong Tea

The sensory evaluation scores, quality indexes (tea polyphenols, caffeine, 8 catechins, soluble sugars, free amino acids, theanine, water extracts and total flavonoids) and 8 mineral elements of different grades of Jinmudan Oolong tea were determined. The results showed that the higher the grade, the higher the water extract content of Jinmudan Oolong tea, and the water extract content of Grand Prize was 1.07% and 1.75% higher than that of first prize and quality prize, respectively, and the differences all reached a significant level (P<0.05). Caffeine, soluble sugar and total flavonoid contents were all significantly higher for low-grade Jinmudan Oolong tea than high-grade (P<0.05). There was no significant difference in tea polyphenol content among the three levels (P>0.05). The ratio of phenol to ammonia was significantly lower in the grand prize than in the first prize and the quality prize (P<0.05). The theanine content was significantly lower in the quality award than in the grand prize and the first prize (P<0.05). Linear regression analysis showed that free amino acids and total flavonoids were significantly negatively correlated with the evaluation score (P<0.05), soluble sugar was significantly negatively correlated with the evaluation score (P<0.01), while water extracts was significantly positively correlated with the evaluation score (P<0.01). There was no significant difference between most mineral elements of different grades of Jinmudan Oolong tea, except for Mn and Fe (P>0.05). The restricted principal coordinates analysis showed that the quality indexes combined with restricted principal coordinates analysis could well distinguish the grade differences of Jinmudan Oolong tea with an R value of 1.00. However, the mineral elements combined with restricted principal coordinates analysis did not well distinguish the quality differences of different grades of Jinmudan Oolong tea. These results could provide a certain reference for the quality judgment of Jinmudan Oolong tea.