International Journal of Agricultural Policy and Research Vol.1(7), pp.197-204,September 2013
© 2013 Journal Issues
Article 13/ID/ JPR76, 08 pages
Original Research Paper
Effects of ethanolic extracts of garlic, ginger and rosemary on the shelf-life of orange juice
Accepted 6 September, 2013
Akponah1a, E., Okoro1b, I.O.,Ubogu2*, M. and Ejukonemu3, F.E.
1aDepartment of Microbiology, Delta State University, P.M. B 1, Abraka, Delta State , Nigeria.
1bDepartment of Biochemistry,Delta State University, P.M. B 1, Abraka, Delta State , Nigeria.
2Department of Biological Sciences, Federal University of Agriculture Makurdi, P.M.B. 2373, Makurdi, Benue State, Nigeria.
3Department of Laboratory Sciences, Delta State Polytechnic, Oghara, Delta State, Nigeria.
*Corresponding author Email: firstname.lastname@example.org
The effects of ethanolic extracts of garlic (Allium sativum), ginger (Zingiber officinale) and rosemary (Rosemarinus officinales) on the extension of the shelf life of orange juice were studied. Two and half milliliters of various extracts were introduced into the orange juice at concentrations of 125, 250, 500 and 1000mg L-1. Positive control samples contained benzoic acid 2.5ml , while negative control sample consisted of orange juice only. It was observed that higher concentrations of 500mgL-1 and 1000mgL-1 of garlic and ginger extracts extended the shelf life of orange juice from Day 0 to Day 2 of storage while rosemary extract at similar concentrations extended the shelf life until Day 3 of storage. Indices for measurement of shelf life included significant loss in ascorbic acid and sugar, drop in pH, changes in colour (from pale yellow to brown) and odour (from good to foul) as well as changes in total fungal and bacterial counts. Rosemary extract showed the highest antibacterial and antifungal activities at all tested concentrations and the garlic extract displayed the least efficiency. Also, all the extracts displayed a higher suppressive action against fungal isolates than the bacterial isolates as well as against the Gram positive bacterial isolates than Gram negative bacterial isolates.
Key words: Allium sativum, Zingiber officinale Rosemarinus officinale , shelf-life, orange juice.