| This study included four aspects: the quality research on hawk tea in Chongqing.Wuxi,the influences of processing methods and maturity on flavor characteristics of hawk tea,the therapeutic effects of hawk tea on acute colitis mice,which aimed to develop and innovate hawk tea products with quality assurance,rich flavor characteristics,health-care functions.A series of experimental measurements have been comprehensively conducted on the taste,aroma and other sensory characteristics of the hawk tea,the biochemical components and aroma components,and the anti-inflammation effect,so to provide theoretical basis and technical guidance for the exploitation and utilization of wild natural resources of hawk tea.The main research contents and results were presented as follows:1.17 hawk tea were selected as raw materials to detect and analyse the main flavor components(flavonoids,polyphenols,catechins,amino acid monomers,etc.)and aroma components respectively.The results showed that:(1)In the 17 hawk tea,the content of total flavonoids was 1.52% ~ 2.51%;total polyphenol content was 6.27% ~ 11.79%;the content of catechins was 3.99% ~ 9.54%;the soluble sugar content was higher with a range of 4.92% ~ 9.26%;the content of soluble protein was 0.72% ~ 2.40% and the total amino acid content was 0.99% ~ 4.01%.Valine,cysteine and threonine content was the highest in the amino acid monomer and the content of fresh flavor amino acid was low.(2)The ingredients of characteristic aroma with pungent camphor odor in hawk tea included bornyl acetate,spathulenol,alpha-copaene,etc.Lauraldehyde,alpha-pinene,3-carene,beta-ionone,etc.contributed to fruit odor.Alpha-tantalol,alpha-paleotype,etc.contributed to wood,herb incense and smoke odor.2.The mature shoots of hawk tea as raw materials were processed using the method of roasted green tea,sun-dried green tea and black tea.The effects of different processing methods on quality characteristics of hawk tea were analyzed by studying three kinds of processing methods of the hawk tea in the sensory quality,the difference of main biochemical components and aroma components.The results showed that different processing methods could affect the quality of hawk tea.Hawk black tea had the best flavor quality which showed the low contents of some substances with bitter taste,such as flavonoids,polyphenols,flavonols etc.This tea sample had sweet and fragrance,heavy and thick taste and decreased characteristic pungent aroma components,but at the same time,some components with flowery-fruity,sweet,fragrant,nerolia and balsam aroma were increased.So the overall aroma has improved.Sun-dried hawk green tea flavor quality were second.Although the contents of flavonol glycosides had low taste threshold value and the bitter taste were higher,the contents of amino acids which contribute to the freshness of tea soup were also higher.Thus compared with roasted hawk green tea,the bitter flavor and the pungent smell was weaker.The contents of flavonoids,polyphenols,catechins,etc.were highest in roasted hawk green tea that it presented bitter taste,lack of freshness,showing the most typical lauraceae plants unique aroma,strong irritant in poor flavor quality.3.In order to study the differences of the sensory quality,main biochemical components and aroma components in hawk tea of four different maturity,hawk bud tea,primary leaf tea,medium maturity leaf tea,hawk mature leaf tea were selected as raw materials and processed using green tea method.The results showed that four kinds of hawk tea sensory evaluation scores decreased gradually with the increase of different maturity and the contents of amino acids,polysaccharides,saponin decreased gradually,while the total flavonoids and total phenolics,soluble sugar,total catechins,flavonols and flavonol glycosides contents increased gradually.Some pungent aroma components contents were also increased gradually,so the flavor quality of the hawk tea decreased gradually as the mature degrees of hawk tea leaves increased.Hawk bud tea had the best flavor quality.Some substances with bitter flavor,such as flavonoids,polyphenols,flavonols and flavonoid glycosides were the lowest and sweet and fragrance,heavy and thick taste,characteristic pungent aroma components decreased.The overall aroma was improved.Primary leaf tea and medium maturity leaf tea were second in flavor quality.The contents of flavonoids,polyphenols,flavonols and flavonoid glycosides,were increased,while amino acids contents were decreased.Compared with hawk bud tea,the bitter tastes and pungent aroma of primary leaf tea and medium maturity leaf tea were increased.The majority of components including flavonoids,polyphenols,catechins,etc.were highest in hawk mature leaf tea,but the amino acid content was the lowest.The tea infusion showed bitter flavor,lack of fresh flavor and the most typical lauraceae plants unique aroma.Compared with the other three kinds of hawk tea,the flavor quality was poor and the contents of functional components,like flavonoids and polyphenols were highest.4.The water extracts of hawk bud tea,primary leaf tea,medium maturity leaf tea,hawk mature leaf tea were selected to treat acute UC mice induced with DSS.The efficacy of hawk tea in acute UC mice was investigated according to general observation(diet and drinking,body weight,DAI),the researchs of colonic tissue morphology in mice(colon length,spleen weight,H&E staining of colon tissue pathology morphological,histological score),and plasma proinflammatory cytokines(TNF-α,IL-1β,IL-6,IL-12)detection.The results showed that:(1)From the third day of modeling,the mice in model group appeared positive fecal occult blood.It appeared visible blood stool to the naked eye or loose stool in day 5 ~ 6,accompanied with weight loss,diet and drinking reduced in mice and increased DAI index significantly.With the modeling time prolonged,the symptoms gradually increased.The symptoms of colitis in mice were recovered and alleviated by mesalazine and four different maturity degree of hawk teas.Compared with model mice,the decrease of body weight,diet and drinking,and DAI index reached extremely significant differences.The therapeutic effect of hawk mature leaf tea was comparable to that of positive control drugs and was inferior only to the normal group.(2)Compared with normal group,the model group mice’s colon significantly shortened,spleen significantly became heavier,tissue seriously injured,intestinal gland structure disappeared and connective tissue hyperplasia accompanied by a large number of inflammatory cells infiltration,partial lamina propria edema,histological score as high as 7.67.Mesalazine and four different maturity of hawk tea extracts can restored the colon length and spleen weight,relieved swelling tissue morphology obviously.Compared with the model group mice,the number of goblet cells increased,no muscularis mucosa tissue edema and hyperemia,pathological damage score decreased significantly.Hawk mature leaf tea had best effect and achieved the level of drug treatment.(3)The contents of TNF-α,IL-1β,IL-6 and IL-12 in mice plasma of model group were much higher than normal group and these therapeutic group have reduced contents of proinflammatory cytokines in UC mice plasma.The therapeutic effect was: mesalazine > hawk mature leaf tea > medium maturity leaf tea > primary leaf tea > hawk bud tea.(4)According to Pearson analysis results between contents of main efficacy components in four different maturity hawk tea and some testing indexes of its resistance to colitis,the main components of the determination of the anti-colitis were: total flavonoids,total polyphenols,C,EGCG,NGC and TC,among which total flavonoids were the most important and polysaccharides,saponins,EC and EGC can help the total polyphenol total flavonoid and other ingredients work together in acute UC mice. |
