Antimicrobial Activity, Physicochemical and Mechanical Properties of Aloe (Aloe debrana) Based Packaging Films
Gashaw Assefa Yehuala
Addis Ababa Science and Technology University, P.O.Box:16417, Addis Ababa, Ethiopia
Shimelis Admassu Emire
Addis Ababa University, Food Engineering Program, School of Chemical and Bio-Engineering, Addis Ababa Institute of Technology, P.O.Box: 33381, Addis Ababa, Ethiopia.
*Author to whom correspondence should be addressed.
Abstract
Aims: To develop aloe based packagings films and evaluate the antimicrobial activity, physicochemical and mechanical properties at different proportions of Aloe debrana extract, papaya leaves extract, gelatin and glycerol.
Study Design: Completely randomized design (CRD)
Place and Duration of Study: Addis Ababa University, between May 2010 and November 2012.
Methodology: The Aloe and papaya leaves extracts were analyzed for their antimicrobial activity, transparencies and colours. The packaging films were developed by adding various concentrations of gelatine and glycerol into the solution of Aloe debrana and papaya extracts. Films were evaluated for their antimicrobial activity, physicochemical and mechanical properties. The antimicrobial activity of Aloe based films were tested on E. coli, S. typhi, S. aureus, C. albicans and F. xylarioides
Results: All films exhibited inhibitory zones on the test microorganisms used in this study. A wide inhibition zone (6.52cm2) was observed on S. typhi growth whereas the least (4.20 cm2) was found on C. albicans. The developed films were soluble in water with maximum solubility (90.49%) for P1,1 and lowest (44.57%) for P0,2. The film solubility significantly increased as the concentration of glycerol augmented and decreased as the concentration of gelatine increased. Film with P0.5,2 has revealed highest tensile strength where as the lowest was obtained by film made-up from P0.5,1. Increasing gelatine concentrations significantly increases the tensile strength but glycerol has an opposite effect on the tensile strength. Film P1,2 showed the maximum elongation (180%) and the minimum elongation (89%) was obtained for P0.5,1.
Conclusion: The outcomes indicated that Aloe debrana extract and papaya leaves extract with gelatin and glycerol could be good raw materials for the development of effective antimicrobial packaging films. The developed packaging films exhibited their potential for antimicrobial activity which can be used as one of the most promising packaging systems.
Keywords: Aloe extract, antimicrobial activity, mechanical properties, papaya extract, packaging films, pathogenic microorganisms, physicochemical properties