Evaluation of the pH and titratable acidity of teas commercially available in Brazilian market

OBJECTIVE: Tea has been considered a healthy alternative to other industrialized beverages. The objective of this study was to assess the erosive potential of teas commercially available in Brazil by pH and titratable acidity measures. METHODS: Eighteen teas available in Brazilian market were selected for this study (read to drink and brewed tea), and a brand of yerba mate (Ilex paraguariensis). Each product was analyzed for pH and titratable acidity. For comparison between different kinds of teas, the Student t test was used. RESULTS: The mean pH values for ready to drink teas ranged between 2.89 and 4.03, while for the brewed teas and yerba mate the values ranged between 6.75 and 7.89. The difference between the two groups was significant (p < 0.05). Regarding titratable acidity, the ready to drink teas showed mean values ranging between 3.77 ml and 12.68 ml. Brewed teas (including yerba mate) were not tested for titratable acidity because their pH values were greater than 7.0. CONCLUSION: Among the teas commercially available, ready to drink teas have lower pH values and higher titratable acidity compared to other teas. It suggests that they have an erosive potential.

研究目的：茶被视作各类工业化饮品的健康替代选择。本研究旨在通过pH值与滴定酸度（titratable acidity）测定，评估巴西市售茶饮的侵蚀性潜能（erosive potential）。
研究方法：本研究选取巴西市场在售的18款茶饮（包含即饮型茶饮与冲泡型茶饮）以及一款马黛茶（yerba mate，学名巴拉圭冬青Ilex paraguariensis）作为受试样品。所有受试产品均开展pH值与滴定酸度检测；为比较不同品类茶饮的组间差异，采用学生t检验（Student t test）进行统计学分析。
研究结果：即饮型茶饮的平均pH值介于2.89至4.03之间，而冲泡型茶饮与马黛茶的pH值则处于6.75至7.89区间，两组间差异具有统计学意义（p<0.05）。滴定酸度方面，即饮型茶饮的平均滴定酸度范围为3.77 ml至12.68 ml；由于冲泡型茶饮（含马黛茶）的pH值均高于7.0，故未对其进行滴定酸度检测。
研究结论：在巴西市售茶饮中，即饮型茶饮的pH值低于其他品类茶饮，而滴定酸度更高，这表明即饮型茶饮具备一定的侵蚀性潜能。