Diffusity of selective bioactive subtances in a release-on-command system

Abstract

The objective of this study were to investigate the reaction of some plants; Lawsonia inermis, Stevia rebaudiana, Brassica oleracea and Allium sativum L towards the diffusivity and color stability. They were extracted and the bioactive compounds were studied. L. inermis was extracted by soxhlet apparatus using ethanol and petroleum ether as solvent whereas ethanol and hexane were used in the extract of S. rebaudiana. All the extract was tested against B. subtilis (Gram-positive bacteria), E. coli (Gram-negative bacteria), A. fumigatus and yeast by disc diffusion method. Both extract showed good inhibitory effects towards the growth of the entire micro organism where the maximum inhibition (3.2±0.1 cm) was recorded for L. inermis against B. subtilis. Include in this project was also involves some preliminary observation on the colour stability of anthocyanin in B. oleracea towards the day of storage. Anthocyanins behave like pH indicators as a result of their amphoteric nature. Anthocyanin extracted from B. oleracea are most stable in regards to degradation by thermal and change it colour to red at pH 1 and pH 2, gradually change to purple as the pH is increased to neutral and change to yellow at pH 13 and pH 14. Besides, antibacterial starch (wheat)-based film also has been studied by incorporation of garlic oil from A. sativum L as a natural antibacterial agent. Initially, 10mg of garlic oil incorporated into the starch-based film was tested against two types of food pathogenic bacteria, E. coli and B. subtillis through two types of bacterial inhibition tests, (i) agar plate test and (ii) liquid broth test. From the study, a greater inhibitory effect was observed on B. subtillis.