Stable carbon isotopic characterization of rice vinegar protein as an intrinsic reference for discriminating the authenticity of brewed rice vinegar

Authors

Chun-Jen Fang, Department of Agricultural Chemistry, National Taiwan University, Taipei City, Taiwan
Hsin-Cheng You, Taiwan Food and Drug Administration, Taipei City, Taiwan
Zih-Ling Huang, Taiwan Food and Drug Administration, Taipei City, Taiwan
Che-Lun Hsu, Taiwan Food and Drug Administration, Taipei City, Taiwan
Chia-Fen Tsai, Taiwan Food and Drug Administration, Taipei City, Taiwan
Ya-Tze Lin, Taiwan Food and Drug Administration, Taipei City, Taiwan
Ya-Min Kao, Taiwan Food and Drug Administration, Taipei City, Taiwan
Su-Hsiang Tseng, Taiwan Food and Drug Administration, Taipei City, Taiwan
Der-Yuan Wang, Taiwan Food and Drug Administration, Taipei City, Taiwan
Nan-Wei Su, Department of Agricultural Chemistry, National Taiwan University, Taipei City, TaiwanFollow

Keywords

Authenticity, EA-IRMS, Protein, Stable isotope ratio, Vinegar

Abstract

Rice vinegar plays an important role in daily life. However, some unscrupulous manufacturers may deliberately add synthetic acetic acid in vinegar products to reduce fermentation time and save production costs. To protect the rights and health of consumers, vinegar authenticity must be controlled. The rice vinegar protein was used as an intrinsic reference and its stable carbon isotope ratio (δ¹³C_protein) was analyzed by elemental analyzer-isotope ratio mass spectrometry. The stable carbon isotope ratio difference between the acetic acid and the rice vinegar protein (Δδ¹³C_{acetic acid-protein}) was calculated to evaluate vinegar authenticity. Sixteen rice vinegar samples were analyzed and a stable carbon isotopic pattern of rice vinegar was established by the 95% confidence interval for Δδ¹³C_{acetic acid-protein} (0.27‰ to 2.10‰). An acetic acid adulteration curve of Δδ¹³C_{acetic acid-protein} was also assumed according to the data from rice vinegar samples, and its validity was confirmed by rice vinegar deliberately blended with acetic acid at different ratios (25, 50, and 75%). The Δδ¹³C_{acetic acid-protein} values of the adulterated vinegars decreased with increasing amounts blended acetic acid, but the δ¹³C_protein values did not, showing that rice vinegar protein could be used as an intrinsic reference for identifying the adulterated rice vinegar. The rice vinegar adulterated with acetic acid at higher than approximately 10% could be detected.

Abstract Image

Recommended Citation

Fang, Chun-Jen; You, Hsin-Cheng; Huang, Zih-Ling; Hsu, Che-Lun; Tsai, Chia-Fen; Lin, Ya-Tze; Kao, Ya-Min; Tseng, Su-Hsiang; Wang, Der-Yuan; and Su, Nan-Wei (2022) "Stable carbon isotopic characterization of rice vinegar protein as an intrinsic reference for discriminating the authenticity of brewed rice vinegar," Journal of Food and Drug Analysis: Vol. 30 : Iss. 1 , Article 4.
Available at: https://doi.org/10.38212/2224-6614.3398

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