Study On Instrumental Analysis Techniques Of Tea Shoot Tendernes And Its Temporal And Spatial Variation

Shoot tenderness-keeping ability of Camellia sinensis (L.) O. Kuntze as one of important characters needs to be considered during resources and breeding work is the ability to maintain the tenderness of tea shoot. Traditional method that take confusion to breeding work is sensory evaluation with confuse concept and unclear measure method, therefore few studies had reported on this field. The need to establish a scientific measure of tenderness including the physical properties, sensory evaluation and chemical components as a comprehensive and complicated method would support further research.1. The establishment of method for expressing tenderness of tea shoot by the maximum shearing force of stem was completed with texture analyzer. Those results were as follow:1) The spatial location of stem and the maximum shearing force were related significantly (r=0.623, P<0.0001), from the top tea shoot to the lower part of it, the more shearing force and the less tenderness.2) The maximum shearing force and maturity of tea shoots had a significant linear correlation (r=0.427, P<0.0001); in the condition of same maturity the higher maturity tea shoot had less tenderness. Took the third stems from one bud and three leaves and one bud and five leaves as example, the former had more tenderness and less force.3) The maximum shearing force had relation with plucking time, from April to July took tea shoots with the same maturity as comparison, the latter of plucking time, the less tenderness and the more shearing force. And the treatment of pruning could improve the tenderness of new born tea shoots.4) The stem of section III is an inflection point with tenderness changing. The stems before section III aged not obviously and were the sections that tenderness changed slowly; and those after section III (such as section IV and V) aged dramatically as parts of tenderness changing straightly. The difference of tenderness regulation existed between Longjing 43 and Zhongcha108 were due to cultivars discriminations.2. The shearing forces of stem and sensory evaluation scores of leaf showed a very significant positive correlation (r=0.826, P=0.0001), which proved that those two numeric properties of tea shoot had consistent results, and pointed out that shearing force could be an alternative method of sensory evaluation to reflect the difference of tenderness of tea shoot.3. Tea shoots with maturity of one bud and five leaves as materials, took their shearing force of stem and measured their contents of lignin, cellulose, amino acids, total polyphenols, catechins and water. 25 indicators were selected from those 44 tenderness relative indicators by correlation analysis and principal component analysis. Made those 25 indicators and shearing force as variables, carried out the cluster analysis with materials with different tenderness.A holding of measure method of evaluating the tenderness of tea shoots was established.