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A simple and rapid turbidimetric method for determining catechins in beverages
Author(s) -
Nakayama Motokazu,
Shigemune Naofumi,
Tsugukuni Takashi,
Tokuda Hajime,
Miyamoto Takahisa
Publication year - 2010
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2010.02372.x
Subject(s) - chemistry , absorbance , hydrogen peroxide , turbidimetry , chromatography , catechin , tannin , polyphenol , gallate , turbidity , epigallocatechin gallate , nuclear chemistry , food science , organic chemistry , oceanography , antioxidant , geology
Summary We have developed a simple and rapid turbidimetric method to determine catechins based on the fact that many polyphenols produce hydrogen peroxide in an alkaline environment and that hydrogen peroxide oxidises cerium to generate cerium oxide precipitates. Four catechins (epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate) aggregated with these precipitates to form massive precipitates with increased turbidity. The catechins solution (0.18 mL) was mixed with 0.02 mL of 1% CeCl 3 solution, and absorbance (650 nm) was measured immediately after agitation for 3 min using a spectrophotometer. Absorbance was strongly correlated (0.99) with the concentration of each catechin compound. For commercially bottled green tea, the estimated catechin content determined using this turbidimetric method showed better correlation with the content determined by high‐performance liquid chromatography than that determined using ferrous tartrate method, which is the official Japanese method for determining the tannin content of green tea.