*Article* **Antioxidant Activities, Phenolic Profiles, and Organic Acid Contents of Fruit Vinegars**

#### **Qing Liu 1, Guo-Yi Tang 1, Cai-Ning Zhao 1, Ren-You Gan 2,\* and Hua-Bin Li 1,\***


Received: 6 March 2019; Accepted: 22 March 2019; Published: 27 March 2019

**Abstract:** Fruit vinegars are popular condiments worldwide. Antioxidants and organic acids are two important components of the flavors and health benefits of fruit vinegars. This study aimed to test the antioxidant activities, phenolic profiles, and organic acid contents of 23 fruit vinegars. The results found that the 23 fruit vinegars varied in ferric-reducing antioxidant power (FRAP, 0.15–23.52 μmol Fe(II)/mL), Trolox equivalent antioxidant capacity (TEAC, 0.03–7.30 μmol Trolox/mL), total phenolic content (TPC, 29.64–3216.60 mg gallic acid equivalent/L), and total flavonoid content (TFC, 2.22–753.19 mg quercetin equivalent/L) values. Among the 23 fruit vinegars, the highest antioxidant activities were found in balsamic vinegar from Modena (Galletti), Aceto Balsamico di Modena (Monari Federzoni), red wine vinegar (Kühne), and red wine vinegar (Galletti). In addition, polyphenols and organic acids might be responsible for the antioxidant activities of fruit vinegars. The most widely detected phenolic compounds in fruit vinegars were gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, and *p*-coumaric acid, with tartaric acid, malic acid, lactic acid, citric acid, and succinic acid the most widely distributed organic acids. Overall, fruit vinegars are rich in polyphenols and organic acids and can be a good dietary source of antioxidants.

**Keywords:** fruit vinegar; antioxidant capacity; phenolics; flavonoid; organic acid
