For hundreds of years, Taiwan has been famous for its various specialty teas. The sensory features of these teas have been well specialized and standardized through sensory evaluations performed by tea experts in yearly competitions throughout history. However, the question arises of whether young Taiwanese consumers, whose dietary behaviors have become Westernized, agree with the conventional sensory standards and association/postprandial concepts in the traditional tea market of Taiwan. To study young Taiwanese consumers’ ideas towards traditional specialty teas, this research recruited 109 respondents, younger than the age of 30, to taste seven Taiwanese specialty tea infusions of various degrees of fermentation, and their opinions were gathered by questionnaires composed of check-all-that-apply (CATA) questions and hedonic scales. Through statistical analyses, we found that several tea sensory attributes which were emphasized in experts’ descriptive sensory evaluations were not appreciated by the young Taiwanese people. Instead, tea aroma and late sweetness/palatable/smooth/refreshing mouthfeels were the most important sensory attributes contributing to their tea preference. Overall, there would generally be no problem in serving young Taiwanese consumers lightly-fermented oolong teas that generate the highest digestive and lowest heartburn postprandial perceptions.

The market size of varied carbonated teas and bottled ready-to-drink tea products in Taiwan has surpassed that of traditional Taiwan tea with hot infusion. The consumption behavior of Taiwanese consumers for new and varied types of cold infusion tea products has also differed from that of traditional hot infusion ones. More kinds of Taiwan tea with different fermentation levels are gradually being used as raw materials for various cold infusion tea products. Therefore, to study consumers’ responses towards cold-brewed tea has become more important for the market of tea in Taiwan. This study recruited Taiwanese consumers to taste seven Taiwanese specialty tea infusions with various degrees of fermentation, and their opinions were gathered by questionnaires composed of check-all-that-apply (CATA), and temporal check-all-that-apply (TCATA) questions and hedonic scales. We found that both CATA and TCATA data agreed that the sensory features of unfermented and lightly semi-fermented tea infusions could be plainly distinguished from the ones of heavily semi-fermented and fully fermented teas based on correspondence analyses. Through CATA and TCATA, the sensory characteristics of the cold-brewed tea of various fermentation degrees could be clearly identified. The first-hand information of cold tea beverages analyzed through this study could be useful for the development of the market in Taiwan. The proper level of bitterness, astringency, fresh tea leaf flavor, and late sweetness were the essential qualities of cold infusions brewed from lightly fermented teas, which could be the best raw materials for production of cold tea beverages to satisfy as many consumers as possible.

Protein phosphorylation is a crucial post-translational modification that plays an important role in the regulation of cellular signaling processes. Site-specific quantitation of phosphorylation levels can help decipher the physiological functions of phosphorylation modifications under diverse physiological statuses. However, quantitative analysis of protein phosphorylation degrees is still a challenging task due to its dynamic nature and the lack of an internal standard simultaneously available for the samples differently prepared for various phosphorylation extents. In this study, stable-isotope dimethyl labeling coupled with phosphatase dephosphorylation (DM + deP) was tried to determine the site-specific degrees of phosphorylation in proteins. Firstly, quantitation accuracy of the (DM + deP) approach was confirmed using synthetic peptides of various simulated phosphorylation degrees. Afterwards, it was applied to evaluate the phosphorylation stoichiometry of milk caseins. The phosphorylation degree of Ser130 on α-S1-casein was also validated by absolute quantification with the corresponding synthetic phosphorylated and nonphosphorylated peptides under a selected reaction monitoring (SRM) mode. Moreover, this (DM + deP) method was used to detect the phosphorylation degree change of Ser82 on the Hsp27 protein of HepG2 cells caused by tert-butyl hydroperoxide (t-BHP) treatment. The results showed that the absolute phosphorylation degree obtained from the (DM + deP) approach was comparable with the relative quantitation resulting from stable-isotope dimethyl labeling coupled with TiO2 enrichment. This study suggested that the (DM + deP) approach is promising for absolute quantification of site-specific degrees of phosphorylation in proteins, and it may provide more convincing information than the relative quantification method.

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