2020 Volume 67 Issue 12 Pages 493-498
“Geographical Indication (GI) Hokkaido” has been operating since 2018 with the aim of ensuring the quality and branding of wine produced in Hokkaido. The amount of volatile acid, mostly acetic acid, should be regulated for GI certification since excessive amounts contribute to objectionable off-flavors of wine. In this study, a new application of gas chromatography (GC) followed by ethyl acetate extraction was examined as a simple and reliable method of measuring acetic acid in wine. Higher reproducibility (RSD: 2.1 % to 4.4 %) was observed in three types of wine samples with different acetic acid concentrations (254 to 756 µg/mL), accompanied by satisfactory recoveries (98 % to 102 %). The determination range was 254 to 1 236 µg/mL, well covering the required criterion (＜1 000 µg/mL). Significant correlations were recognized between the GC method and high-performance liquid chromatography (HPLC), which has been approved as a screening method for measuring volatile acid in GI wine (r＝0.993, p＜0.0001, n＝22), and also the distilled-titration method (r＝0.974, p＜0.0001, n＝19). Thus, the proposed GC method for the determination of acetic acid in wine samples is simple and reliable; furthermore, it will be useful as an alternative reference based on a different principle to the traditional titration method or the prevalent HPLC method.
