Vitamin C stability in pineapple, guava and baobab juices under different storage conditions using different levels of sodium benzoate and metabisulphite

Vitamin C is one of the most important vitamins in fruit based products and its stability is very critical to guarantee its availability. Stability of vitamin C in baobab, guava and pineapple juices stored at room (22.4°C±1.3), chilling (-1.2°C±0.1) and freezing (-17.3°C±0.2) temperatures and using 0.05% sodium benzoate, 0.005% sodium metabisulphite and combined use of sodium benzoate and metabisulphite at 0.04 and 0.005% respectively was investigated. Results from the study revealed that both storage conditions and levels of the preservatives used significantly affected vitamin C stability in all the three types of juices used. Vitamin C contents were 74.4, 52.4 and 34.7 mg/100 mL for baobab, guava and pineapple juices on the first day of processing. Furthermore, vitamin C was found to be more stable in freezing storage conditions and the combined use of sodium benzoate and sodium metabisulphite at 0.04 and 0.005%, respectively was more effective in stabilizing vitamin C in the fruit juices than the other preservative levels used. It can be concluded that vitamin C stability in the three types of juices was influenced by storage temperature conditions, storage time and levels and types of preservatives used.