Taste chemical components and sensory quality of albino green tea in different shapes

【Objective】The difference of tast chemical components and sensory quality of albino green tea in different shapes was analyzed to provide reference for the development of albino tea variety products and the formulation of appropriate technological process. 【Method】With the fresh leaves of the albino tea tree Baiye No. 1 as raw materials， the albino green tea in the shapes of crimp， granule and pine needle was prepared by bottle stir-frying machine， double pot curler and strip machine， respectively. The conventional quality components， amino acid components and catechin components of the tea were detected by high performance liquid chromatography （HPLC）. Principal component analysis （PCA）， orthogonal partial least squares discriminant analysis （OPLS-DA） and hierarchical cluster analysis （HCA） were used to screen the key characteristic quality components. Finally， sensory evaluation method was used to evaluate tea quality and analyze the relationship between tea quality and characteristic components. 【Result】The polyphenols content of granular shape albino green tea were 17.69% and the phenol-to-ammonia ratio was 2.70， which were significantly lower than those of pine needle shape and crimp shape（P<0.05， the same below）. The total amount of sweet amino acids（23.16 mg/g）， theanine content （18.14 mg/g）， glutamic acid content （1.26 mg/g）， aspartate content （1.74 mg/g）， alanine content （0.13 mg/g）， threonine content（0.33 mg/g） and valine content（0.26 mg/g） were significantly higher than that of pine needle shape. At the same time， the proportion of sweet amino acids was the largest（84.74%）， and the proportion of bitter amino acids was the smallest（11.23%）. Multivariate statistical analysis showed that the different quality components of albino green tea in different shapes were mainly sweet amino acids（theanine， glutamic acid， threonine and glycine）， bitter amino acids （isoleucine， tyrosine， histidine， lysine and arginine）， sweet and slightly bitter proline and cysteine with unknown taste， catechin gallate （CG）， epicatechin gallate （ECG）， three phenols of tea polyphenols， total free amino acids and phenolammonia ratio. The total amount of free amino acids， CG， theanine， glutamic acid， threonine， histidine and isoleucine of granular shape albino green tea were greatly higher than those of pine needle shape and crimp shape. Granular shape （92.83 points） and pine needle shape（92.34 points） were significantly higher than crimp shape（84.43 points） in sensory evaluation， flavor factor of grain shape（28.15 points） was the highest and that of pine needle shape（27.65 points） was the second， the scores of shape， soup color and aroma factors were significantly higher than those for granular and pine needle shapes， and the score of brewed leaf factor was the highest for pine needle shape （9.23 points）. The taste factor was significantly positively correlated with cysteine， ECG and CG， and extremely significantly （P<0.01） or significantly negatively correlated with arginine， tyrosine， lysine and proline. 【Conclusion】Granule albino green tea has the highest proportion of sweet amino acids， low proportions of polyphenols and phenolamine， moderate proportion of ester catechins， and has the best taste quality and comprehensive quality among the three models. Pine needle shape albino green tea has the highest ester catechins， the lowest total bitter amino acids， the highest leaf base score， the second highest taste score， and the comprehensive sensory quality is better than that of crimp shape green tea.