Bioactive compounds and antioxidant activity in commercial mao juice products in Thailand
Mao, belonging to genus Antidesma, has urged more attention in Thailand as antioxidant-rich berries in this past decade. Its juice is extendedly available in the market throughout Thailand with the advertisement of being high in nutrition and antioxidant values. While these selling points are based primarily on scientific research on functional properties of bioactive compounds in fresh mao berries, the value of antioxidant level in commercial mao juice had not yet been reported. It is therefore in our interest to examine actual amount of antioxidants in the commercial juice products. This study selected four brands of ready-to-drink mao juice frequently found in the market and determined their total anthocyanins, total phenolics and antioxidant activities by FRAP and ORAC assay. Freshly pressed juice was evaluated as a benchmark. Effect of heat treatment, commonly used by manufacturers, was also investigated by heating freshly pressed juice at 80°C for 15 min before hot-filled in a glass bottle. The results showed that freshly pressed juice had a total of anthocyanins of 1,344.27 mg cyanidin-3-glucoside eq L-1, phenolics of 3,346.80 GAE L-1, FRAP of 40,142.86 µmol TE L-1 and ORAC of 60,949.0 µmol TE L-1. After heat treatment, these values were remained at 50.08, 63.01, 61.86 and 86.25%, respectively, of fresh juice. It was also found that these respective values from commercial juice were only 1.59-2.84, 12.46-21.75, 7.59-19.34 and 7.93-20.17% of the fresh juice. The substantial lower amount of bioactive compounds and antioxidant activity of commercial ready-to-drink mao juices could resulted, not only from heat treatment process, but also from additional processing steps, product formulation and especially storage. The perception of consumers on functional properties of commercial mao juice was discussed in this paper.
Somsong, P. and Duangmal, K. (2018). Bioactive compounds and antioxidant activity in commercial mao juice products in Thailand. Acta Hortic. 1213, 379-386
Antidesma, Mao, antioxidant, phenolics