DEVELOPING AND CHARACTERIZATION OF CASSAVA STARCH BASED ANTIMICROBIAL PACKAGING FILM BY INCORPORATING NETTLE LEAF EXTRACT

Abstract

Nowadays, to extend the shelf life of foods and to travel the foods safely, packaging that can protect food from chemical, biological and physical influences has become an integral part of food processing technology and its expenditure has reached more than 3,030 billion USA dollars per annum by the year 2020. However, plastics which are non-biodegradable and nonrenewable materials are the main packaging material used in the food industry. Therefore, this study is designed to overcome the limitations and add more important features to the existing packaging materials. In this study, antimicrobial packaging film was produced using a starch extracted from cassava roots, an antimicrobial agent extracted from nettle leaf, and glycerol as a plasticizer. The antimicrobial agent is extracted using ethanol. The antimicrobial activity of the extract was tested on gram-negative and gram-positive bacteria namely Staphylococcus aureus, Salmonella typhi, and E. coli and antifungal (Candida Albicans). Thereafter, the minimum concentration of nettle leaf required for inhibition is determined using the broth dilution method. Then, packaging film from cassava starch, glycerol, and extracted nettle leaf is prepared and its physical, antimicrobial, and mechanical properties are determined. The result shows that the extract exhibits strong antimicrobial activities as all microbes are completely inhibited to grow at an extract concentration of 10 mg/mL. Compared to the other microbes, candida Albicans are less resistant to the extract and ceases to grow at 6 mg/mL extract concentration. The ANOVA analysis, which is based on three factors [starch/glycerol ratio (A), antimicrobial concentration (B), and film thickness (C)] with mixed levels, indicated that all the factors have significant effects on all microbes and the AC and BC interaction effects are significant on all microbes. Regarding the properties of the film, the moisture content decrease from 35% to 22%, solubility increase from 50% to 70% and swelling capacity decrease from 30% to 20% as antimicrobial concentration increases while the mechanical properties which is tensile strength increase from 20Mpa to 27Mpa and elongation break also increase from 60% to 82% with an increase in the antimicrobial concentration. The overall analysis of the result suggests nettle leaf extract and cassava starch are the potential alternative to plastic packaging material for the production of antimicrobial, renewable, and biodegradable food packaging. Therefore, the researcher recommends the players in the packaging industry seriously consider nettle leaf extract and cassava starch as packaging materials of the future.