Effects of different processing techniques on hawthorn leaves substitute tea quality

【Objective】The effects of different processing techniques on the quality of hawthorn leaves substitute teawere studied，and the suitable processing techniques for hawthorn leaves substitute tea were selected，which provided reference for the further development and utilization of hawthorn leaves tea.【Method】Hawthorn（small leaf species）at 1 bud and 2 to 3 leaves state were as test materials，the four processing techniques of direct drying，green tea，white tea，and black tea were used to make hawthorn leaves substitute tea. The effects of different processing techniques on the quality of hawthorn leaf substitute tea were evaluated based on physicochemical components，sensory quality and volatile components.【Result】The contents of water extract，total sugar，total acid and total phenol in hawthorn leaves green tea were the highest，which were 42.23%，424.24 mg/g，1.96% and 59.62 mg/g respectively；the contents of total flavonoids and amino acids of hawthorn leaves white tea were the highest，which were 87.72 mg/g and 77.21 μmol/g respectively；the content of protein in hawthorn leaves black tea was the highest（148.12 mg/g）. The correlation analysis showed that there was a positive correlation among the contents of water extract，total sugar，total acid，total phenol，total flavonoids and amino acids，while the contents of water extract，total acid，total phenol and total flavonoids were negatively correlated with protein content. The contents of water extract and total phenols were positively correlated with taste，and the content of water extract was negatively correlated with aroma. According to principal component analysis，hawthorn leaves green tea had the highest comprehensive score，followed by hawthorn leaves white tea. According to the analysis of sensory quality， hawthorn leaves white tea and hawthorn leaves green tea had sweet taste，fresh aroma and bright orange-yellow color. The comprehensive evaluation scores were 90.15 and 89.90 respectively. The main volatile components identified in the four types of hawthorn leaves substitute tea were mainly alcohols，aldehydes，ketones，esters and olefins. The contents of aldehydes，ketones and esters in hawthorn leaves white tea were the highest，38.93%，16.87% and 17.65% respectively. There were certain differences in the types and relative contents of the main volatile components in each tea. The components with higher contents were 2-hexenal，nonanal，benzaldehyde，acetophenone，methyl salicylate，α-farnesene，etc.【Conclusion】Green tea and white tea processing techniquesare more suitable for the preparation of hawthorn leaves substitute tea. There are certain differences in the types and contents of main volatile components in hawthorn leaves substitute tea under different processing conditions.