茶叶中手性农药残留分析与风险评估研究进展

手性农药存在一个或多个对映体,其对映体在生物活性、毒性、环境行为、降解代谢等方面可能存在差异。茶叶作为三大无酒精饮品之一,其质量安全问题备受关注。虽然目前更关注手性农药外消旋体残留总量,但随着分析技术的发展,同时为了更好地发挥药效、减少残留及对非靶标物危害,充分了解茶叶中手性农药对映体的立体选择性行为,分析在茶叶中的残留降解规律,建立对映体的残留限量标准显得尤为重要。综述了茶叶中手性农药对映体残留检测技术现状,如液相色谱法、气相色谱法和超临界流体色谱法等方法,并对手性农药对映体在茶叶中的残留降解行为和风险评估进行归纳和展望,为后续深入开展茶叶中手性农药对映体的相关研究提供借鉴。

分光光度法测定茶游离氨基酸总量标准溶液的选择

讨论利用GB/T 8314-2013分光光度法测定茶叶中游离氨基酸总量时使用不同标准溶液测定结果的差别。分别使用茶氨酸和谷氨酸标准溶液制作标准曲线,茶叶中游离氨基酸总量测定结果存在显著差异。茶氨酸、谷氨酸标准曲线的相关系数(r^2)分别为0.9860,0.9942。分别采用两种标准曲线,测定结果的标准偏差分别为0.789%,0.659%(n=15),加标回收率分别为68.28%,94.63%。试验结果表明用谷氨酸制作标准曲线优于茶氨酸。建议在茶叶游离氨基酸总量测定中采用谷氨酸标准工作溶液。

Evaluation on Resource Utilization Potential of Typical Agricultural Waste in Southwest China

To impel resource utilization of agricultural waste,four provinces and cities of southwest China were taken as research objects,to analyze yield change of typical agricultural waste in southwest China during 2010-2016,and resource amounts of typical agricultural crops straw and livestock and poultry waste and their nutrient contents in four provinces and cities of southwest China in 2016 were calculated. The results showed that resource amount of typical agricultural waste in southwest China overall showed a continuously increasing trend with the improvement of agricultural comprehensive productivity. Straw resource amount of agricultural crops was dominant by rice and corn,and they accounted for 61. 61% of total amount in southwest China. Livestock and poultry manure was dominant by cattle and pig excrement,and they accounted for 89. 59% of total in southwest China. Seen from distribution region,the resource amount sequence of typical agricultural waste in southwest China was Sichuan > Yunnan > Guizhou > Chongqing. N,P_2 O_5 and K_2 O in straw resource of typical agricultural crops in southwest China of 2016 were respectively 76. 11 ×10~4,23.36 ×10~4 and 125. 78 × 10~4 t,and total nutrient amount was 22. 53 × 10~5 t. N,P_2 O_5 and K_2 O of livestock and poultry manure resource were respectively 27. 28 × 10~4,12. 87 ×10~4 and 62. 45 × 10~4 t,and total nutrient amount was 10. 26 × 10~5 t. Therefore,resource amount of agricultural waste in southwest China is rich in a long term,and nutrient storage is huge. Its reasonable recycling is favorable for sustainable development of agriculture in southwest China,and has important actual significance for guaranteeing crop yield and decreasing chemical fertilizer use.

葡萄间作模式对茶树新梢品质及呈色的影响

为研究茶树与葡萄间作模式下,间作作物对茶树新梢生化成分及呈色的影响,以单作茶园的一芽二叶茶叶新梢微波杀青固样为对照,间作葡萄茶园的一芽二叶茶叶新梢微波杀青固样为材料,对其生化成分进行测定。结果表明,单作模式下的茶树新梢芽叶呈紫红色、粗老,葡萄间作模式下的茶树新梢更嫩绿,且色泽更光亮;微波杀青固样的水浸出物、氨基酸、茶多酚、咖啡碱、儿茶素总量、可可碱与单作茶园相比均有一定的变化,变化趋势和大小不完全一致。间作葡萄遮荫后,茶多酚、可可碱、水浸出物及儿茶素总量均降低,儿茶素总量降低最为明显,降低了4个百分点,而氨基酸明显提高,提高2个百分点。茶园间作葡萄有效提高了绿茶品质,是一种对促进生态茶园的发展的茶园栽培管理模式。