| With the improvement of people’s living standard and changes of healthy lifestyle, pure teabeverages would be the future trend. They should meet the demands of consumers who want theoriginal flavor of tea, but there was many questions with tea beverage, such as, unstable quality, lowaroma, the deterioration of aroma in store, restricting the further development of tea beverages. Thisarticle selected teas which were sensitive to water quality, simulated parameters of sensory evaluation,and gas chromatography-mass spectrometry (GC-MS) combined with headspace solid phasemicroextraction (HS-SPME) has been successfully applied to analyze effect of volatile components intea with faint scent brewed by different water quality; the method of green tea liquid aroma extrated byHS-SPME-GC-MS was optimized, then used to study the effect of Ca2+and pH on aroma stability ofgreen tea beverage during storage; the final design of monomers was to explore the mechanism ofaroma changes. The main results were as follows:1. The optimal condition of volatile components of green tea beverages determined byHS-SPME-GC-MS was:50/30μm DVB/CAR/PDM extrating fiber,30mL sample in60mL vial,0.2g/mL NaCl, equilibrated in45℃water for10min,60min of extrating time.2. Ca2+has the greatest influence on green tea with faint scent, Mg2+has little impact under20mg/L, pH has great influence on green tea with faint scent and chestnut-like aroma. The results showedthat the aroma of Huangshan Maofeng tea was influenced by several factors, with descending order ofCa2+>pH>Mg2+; it was found that10volatile components had higher correlation with comprehensiveevaluation of the tea aroma, the analysis in treatment of Ca2+showed that dimethyl sulfide (0.9) andβ-ionone (0.86) were significantly positively correlated with the sensory score, while linalool, limoneneand nerolidol were significantly negatively correlated with the sensory score, the correlation coefficientwere all-0.91; the analysis in treatment of Mg2+showed that dimethyl sulfide(0.64) and octanal (0.56)were positively correlated with the sensory score, the other8components had no significant correlation;the analysis in treatment of pH showed that limonene (0.56) was positively correlated with the sensoryscore, while nonanal (-0.76) was negatively correlated with the sensory score; the analysis of aromacharacter impact (ACI) showed that the aroma skeleton of Huangshan Maofeng tea with faint scent werelinalool, dimethyl sulfide, β-ionone, cis-3-hexenyl hexanoate, heptanal, nonanal, decanal, etc.3. During the storage of green tea beverage, tea aroma ran out freshness after the the addition ofCa2+, while unaffected by pH; the lightness of tea liquor changed great in the first three days of storage,a and b values were on the rise, turbidity increased with the rise of calcium ion concentration; pHdecreased with the extension of storage time, total catechins decreased after sterilization and storage.44aroma components were detected in tea liquor before sterilization, while only26components weredetected after sterilization and the aroma loss was big, through a series of changes during storage, aromacomponents had increased to more than40.4. The high ACI value of linalool, dimethyl sulfide, β-ionone and cis-3-hexenyl hexanoate were proved great contributions to the flavor of fresh scent-flavor green tea. Linalool and dimethyl sulfidehad good inhition on soap of nonanal and other aldehydes, the combination could refect the smell of tea,nonanal and cis-3-hexenyl hexanoate contributed to turn the whole aroma to fruit; Ca2+made the aromadull and unpleasant, while Cl-1had little effect on enjoyment of tea aroma; ACI had great referencevalue on simulating tea aroma, floral of linalool covered other aroma easily, dimethyl sulfidecontributed most to tea aroma and the coordination of fragrance, tea aroma of the fifth formula was thebest and had highest fitting degree with the original tea flavor; the content of dimethyl sulfide,benzaldehyde, cis-3-hexenyl hexanoate and β-ionone decreased obviously with addition of40mg/LCa2+, while the content of linalool and nerolidol rised; the content of benzaldehyde and β-cyclociraldecreased obviously with addition of40mg/L Mg2+, while other components changed little; thetreatment of pH5had little effect. This could partly explain why the water quality impact on aroma oftea liquor, especially the complexation of Ca2+and some volatile compounds might inhibit theirvolatility. |
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