Preparation of Rose Vinegar Rich in Gamma-Linolenic Acid and Analysis of its Nutritional Composition and Antioxidant Activity

Despite the rapid development of various types of fruit vinegar or nutrient-fortified vinegar, the weakened functions or high cost is still the main limiting factor for healthy vinegar. In the present study, a new type of rose vinegar was obtained from raw grain supplemented with natural extract of roses through the cooperative fermentation of multiple microorganisms by adding Mucor circinelloides and lactic acid bacteria. The chemical composition analysis showed that this rose vinegar was rich in various organic acids and amino acids, which endowed the rose vinegar with a special taste and nutritional value. In particular, fatty acid content results revealed that the rose vinegar contained several long-chain unsaturated fatty acids, especially the valuable Gamma-Linolenic Acid (GLA), which was mainly due to the addition of M. circinelloides that could synthesize GLA during the fermentation of vinegar. The antioxidant activity of the rose vinegar indicated that the contents of gallic acid and vanillic acid were relatively high and thus it had a certain scavenging ability on DPPH free radicals, superoxide anion free radicals, and hydroxyl free radicals. This is the first study to develop a healthy vinegar containing GLA with antioxidant activity by combining the rose extract with a variety of beneficial microbial fermentation.