Study on stability of antioxidant activity of fresh, pasteurized, and commercial fruit juice during refrigerated storage

Fruit juice is growing in popularity worldwide due to its excellent wellness properties, and most people usually like to store the juice in the refrigerator to drink it later. The current study was undertaken to compare the stability of antioxidant activity of selected samples (apple, orange, and pineapple) of juice that were fresh (untreated), pasteurized at 70 °C for 30 min, and commercially available in Bangladesh at 4 °C in refrigerated storage conditions for up to 21 days. The fresh juice was prepared by crushing and pressing the fruits using an electric mixer, and the pasteurized juice was prepared by running the fruits through a pasteurization procedure at 70 °C for 30 min in a water bath. The total phenolic content (TPC), total flavonoid content (TFC), total antioxidant activity (TAA), beta-carotene content, and vitamin C content throughout 21 days of refrigerated storage were studied by using standard methods. The study found that TPC and TFC of the fresh juices (apple, orange, and pineapple) were statistically significant (p < 0.05) on 0 and 7 days, whereas pasteurized and commercial juices were statistically significant (p < 0.05) on 0, 7, and 14 days. As for TAA, orange and pineapple juices, except fresh pineapple juice, were statistically significant (p < 0.05) up to 21 days. In the case of beta-carotene content, only fresh and pasteurized orange juices were statistically significant (p < 0.05) on 14 days. Apart from apple, all the juice samples had vitamin C content up to 21 days, and these results were statistically significant (p < 0.05) at 0, 7, 14, and 21 days. In addition, most of the samples showed drastic degradation after 7 days for both bioactive compounds and antioxidant activity. It is concluded that the stored fruit juice at 4 °C in refrigerated storage conditions should be consumed within 7 days to get the desired properties of the juice.