| In the 21 st century,human health awareness has been raised to a new level,so the development of health care products has been hot in recent years.Early studies have shown that many active substances in mulberry leaves have significant effects on several current high-risk diseases,and the emergence of mulberry leaf tea can not only meet the needs of people for drinking tea,but also ingest it the beneficial substances achieve a health care effect.In this study,by evaluating the influence of different mulberry leaf tea processing techniques on the five indicators(Water content,leaching rate,total flavonoids,total polysaccharides and1-deoxynojirimycin),the processing technology with the best health care effect and the best taste was determined.The main findings are as follows:(A)In the sensory evaluation of all samples of mulberry leaf green tea,mulberry leaf steamed green tea and mulberry leaf black tea,it was found that the samples treated with different process conditions had effects on the final score.Among them,the blanching conditions in mulberry leaf green tea have the most obvious effect on the quality;In the processing conditions of steamed green tea,the steaming time has no obvious effect on the quality;In mulberry black tea,the degree of fermentation has a significant effect on the final quality.The specific conclusions are as follows:1.In the sensory evaluation results of Roller killing mulberry leaf green tea samples,the quality of the samples with blanching conditions of 330?-60 s and 380?-40 s is significantly higher than 180?-180 s.The drying time has no significant effect on the quality of the final tea.The shape of the dry tea has ultimately been determined by the drying method.The quality of the mulberry leaf green tea after the aroma treatment is slightly higher than that of the un-titian mulberry leaf green tea.2.In the sensory evaluation results of the mulberry leaf steamed green tea sample,the steamed green tea sample quality and quality score is higher than that of the Roller killing mulberry leaf green tea;the quality of the steamed green tea with one bud and one leaf material is significantly higher than the steamed green tea with two position leaf material.The longer the steaming time,the higher the quality of tea.3.In the sensory evaluation results of mulberry leaf black tea,the blanching treatment is still an indispensable stage in the formation process of mulberry leaf tea.Controlling good fermentation conditions has an extremely significant effect on the final quality.The quality ofmulberry leaf black tea fermented by natural conditions is obviously lower than that of instrument fermentation,and by comparison of instrument fermentation effects,it is found that the fermentation time occupies a dominant position in fermentation conditions.4.Through the interaction surface optimization design,the three factors interact with each other to obtain the optimal processing conditions of mulberry leaf tea according to the model.When drying for 12 h,killing temperature 330?,killing time 60 s,the predicted value of the sensory evaluation score under this condition 84.6 points.(B)The tea-making process analyzes the results of the determination of the contents of the five substances(Water content,leaching rate,total flavonoids,total polysaccharides and1-deoxynojirimycin)from three types of mulberry tea as follows:1.The most measured results of the five substances in 48 samples of mulberry green tea showed that the water content of the samples were all between 5% and 7%,most of the samples were between 6% and 7%,and very few samples were around 5%.The processing conditions of very few samples are 330?-60 s blanching conditions,and all have been processed by aroma treatment.Due to the low efficiency and uneven heating,the drum-firing cannot replace the dryer for drying operation.The total leaching rate of the sample materials is between 25% and 35%,and the total leaching rate of most samples is around 30%.When the blanching condition is 330?-60 s,the total leaching rate of the sample after the titian treatment is significantly higher than that of the sample without the aroma treatment,and whether the drying or drying method has no significant effect on the total leaching rates.The total flavonoid content of the samples is between 7 mg/g~19 mg/g.When the blanching condition is 180?-180 s,the total flavonoid content of the sample titian treated with 120? is significantly higher than that of the un-titian or the titian temperature of 80?.The total flavonoid content of fresh leaves at the temperature of 80? and 120? was higher than that in air-cured leaves.The total polysaccharide content of the samples is between 15 mg/g~35 mg/g.Through the process comparison,it was founded that the total polysaccharide content of the air-dried leaf samples is significantly higher than that of the fresh leaves.Whether to use the aroma technology and drying methods has less effects on the total polysaccharide content.The content of 1-deoxynojirimycin was between 0.5 mg/g-2 mg/g,and it's content decreased significantly with the increase of the blanching temperature.2.The final determination results of five substances in 6 samples of mulberry leaf steamed green tea showed that the water content of the samples were all between 7% and 8%,and the difference in water content between the samples was extremely small.The totalleaching rate of the sample material is between 25% and 30%,and the total leaching rate of the sample with only one bud and one leaf after 180 s steaming treatment is 25%.The total flavonoid content of the sample varies according to the leaf positions.The total flavonoid content of the two-leaf sample is 18 mg/g,and the total flavonoid content of the one-bud one-leaf sample is 10 mg/g.The total polysaccharide content of the sample showed a downward trend with the increase of steaming time.The content of 1-deoxynojirimycin in the two leaves was not much different in the samples,and did not significantly affect the final content.The 1-deoxynojirimycin in samples with one bud and one leaf as the material has a significant effect with time increased.3.The final measurement results of the five substances in 18 mulberry leaf tea samples show that the water content of the samples is between 7% and 9%,and the water content of the samples under different treatment conditions is significantly different,mainly manifested in the fermentation conditions.The water content of the heavy fermentation(30?,95 RH%,12 h)sample is low,only about 7%.The total leaching rate of the samples is between 15% and25,while the total leaching rate of the samples processed by different processes is significantly different,and the sample has the lowest total leaching rate after heavy fermentation(30?,95 RH%,12 h).The total leaching rate of the sample material in the flat frying method is often higher than that of hot air drying.In the total flavonoid content of the sample,the longer the fermentation time,the lower the total flavonoid content.The total flavonoid content in instrument fermentation is higher than that in natural fermentation.Different instrument fermentation conditions have significant differences in the final total flavonoid content.The total polysaccharide content of the samples is between 5 mg/g-30 mg/g,and the fermentation conditions were(25?,85 RH%,8 h)was the highest.The content of1-deoxynojirimycin in the samples is between 0.8mg/g-2.2mg/g.The content of1-deoxynojirimycin in the samples without titian treatment is significantly higher than that of the titian samples under the same conditions,and the content of 1-deoxynojirimycin in the heavy fermentation sample is higher than that in the light fermentation. |
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