Submitted in fulfillment of the requirements for the degree of Master of Science. ABSTRACT This thesis reports on the application of hurdle technology by examining the effects of Diplazium esculentum Retz, and Stenochlaena palustris incorporated into sodium alginate as edible coating on figs (Ficus carica L.) combined with modified atmosphere packaging (MAP) at 5±1°C. The objectives are to evaluate the: 1) antimicrobial property of D. esculentum Retz. and S. palustris extracts; 2) effectiveness of sodium alginate-based edible coating and MAP on the shelf-life of figs; and 3) potential of alginate-based edible coatings incorporated with 1% D. esculentum Retz. and S. palustris extracts in combination with MAP on the extension of shelf-life and preserve the quality of figs. As the first objective, the antimicrobial activity of D. esculentum Retz. and S. palustris leaves extracts were tested using a disc diffusion method. Based on the result obtained, the use of 1.5% of alginate incorporated with 1% of the plant extracts formulation was suitable to maintain the quality of figs as it exhibited the largest inhibition zone. For the second objective, figs were coated with 0.5%, 1% and 1.5% of alginate to find the optimal formulation of edible coating. In another set of experiments, figs were stored at different gas concentrations i.e., 1) 10% CO2 + 5% O2 + 85% N2, 2) 15% CO2 + 5% O2 + 80% N2 and 3) 20% CO2 + 5% O2 + 75% N2 Overall, the shelf life of figs coated with 1.5% alginate was extended to 16 days and the use of 20% CO2 + 5% O2+75% N2 gas mixture gas compositions extended the shelf life of figs for 15 days. For the final objective of this thesis, the effects of antimicrobial compounds of D. esculentum Retz. and S. palustris incorporated with 1.5% of sodium alginate edible coating, combined with modified atmosphere packaging using 20% CO2 + 5% O2+75% N2 gas mixture was studied with figs stored at 5±1°C for 25 days. Figs packed in polypropylene bag without gas mixture and edible coating served as control. The addition of D. esculentum Retz. extracts were able to maintain ideal gas composition within the packaging, retain fruit firmness, minimise loss of titratable acidity while S. palustris extracts helped to minimise the change of pH, maintain total soluble solids level, prevent a drastic colour change of the fruits, and prevent microbial growth. Overall, the incorporation of D. esculentum Retz. and S. palustris extracts with MAP allowed for the storage of figs for 25 days.
Thesis (Degree) -Universiti Teknologi Brunei, 2021.