ANTIBACTERIAL ASSESSMENT OF ALOE VERA (Aloe vera chinensis Linn) CORTEX EXTRACT AND ITS APPLICATION AS INHIBITOR FOR KING PRAWNS (Macrobrachium rosenbergii Linn) SPOILAGE DURING STORAGE AT 5oC

Abstract

Aloe vera (Aloe vera chinensis Linn) cortex contains antibacterial compounds such as aloe emodin and
aloin, that have potency as natural preservative for foods. The objectives of the research were to determine
the minimum concentration of aloe vera cortex extract to inhibit bacterial growth, and the effects of soaking
in the extract and storage at 5oC on the quality parameters of king prawns. The concentrations of extract
were varied i.e. 125, 250, 500 and 1000 μg/ml, respectively, and minimum concentration of extract for
inhibition of Pseudomonas fluorescens was determined by Minimum Inhibitory Concentration (MIC)
method. Antibacterial compounds in the extract were analyzed by HPLC and TLC methods. TPC, TVBâ€N,
TMA, pH and organoleptic characteristics of soaked king prawns were evaluated. The results showed 500
μg/ml aloe vera cortex extract was an optimum concentration, and soaking for 90 minutes was able to
inhibit and to reduce one log cycle of bacteria population. Aloe vera cortex extracts contained 18.21 ppm
aloe emodin and 15.5 mg/g aloin (1.55%). After 6 days storage at 5oC, therefore the king prawns was performed
by TPC 3.9 x 105, TVBâ€N 28,6, TMA 4.60 and pH 7.7. The best quality of king prawns was resulted
by 60 minutes soaking with organoleptic score 7.
Keywords: Aloe vera; antibacterial; aloe emodin; aloin; king prawns.