Preservative Effects of Gmelina arborea Fruits and Nauclea latifolia Stem Bark Extracts on Fruit Juice in Comparison with a Known Chemical Preservative

摘要

Fruit juices are liable to spoilage as a result of fermentation by microorganisms. This study is intended to provide information on preservative of fruit juices with plant extracts. The preservative effects of Gmelina arborea fruit and Nauclea latifolia stem bark extracts in apple and pineapple juices were assessed in comparison to chemical preservative (sodium benzoate) as a positive control and refrigeration at 4 °C as a negative control measures. Decrease in microbial load during storage was observed in the prepared juice samples. G. arborea fruit extract in microbial inhibition was more potent followed by sodium benzoate and N. latifolia stem bark extract. G. arborea preserved juices were of better choice in sensory evaluation for acceptability than N. latifolia and sodium benzoate preserved juices. Phytochemical screened from the extracts are saponins, tannins, flavonoids, alkaloids and steroids. The titratable acidity of the prepared juices evaluated G. arborea of lower titratable acidity value than N. latifolia. The results has provided a partial support for the use of G. arborea fruits and N. latifolia stem bark extracts for preservation of fruit juices. The use of N. latifolia and G. arborea as preservative agents have not been documented and could be potential sources of natural preservative agents for future use in preservation of alcoholic and non alcoholic beverages.