Conference Publications

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Browsing Conference Publications by browse.metadata.impactarea "Advanced Functional Materials"

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    Active nanocomposite films based on low density polyethylene/organically modified layered bouble hydroxides/thyme oil to retain retail shelf life and quality of hass avocados
    (2020-12) Kesavan Pillai, Sreejarani; Sivakumar, D; Ray, Suprakas S; Obianom, P; Eggers, Sharon K; Mhlabeni, T
    In this study, the ability of an active film containing volatile bioactives in post-harvest disease control and preservation of quality in avocados is explored as a non-traditional treatment method. Antimicrobial transparent flexible trilayer low density polyethylene (LDPE) films containing organically modified layered double hydroxides (OLDH) and plant bioactive-thyme oil (TO) were made using single step blown film extrusion. Antifungal effects of the packaging in comparison to commercial treatment and untreated control showed considerable reduction in anthracnose disease events in ‘Hass’ cultivar of avocados while improving the fruit quality. 2wt% OLDH loading improved the oxygen and moisture barrier properties while not affecting the transparency of the film. The results suggest that the synergistic effect of barrier and antimicrobial properties of the controlled volatile bioactive release of the nanocomposite film can be utilised as a prospective strategy to modify the headspace gas composition to combat anthracnose disease in avocados.
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    Chemical modification of sugarcane bagasse with chitosan for the removal of phosphates in aqueous solution
    (2020-11) Manyatshe, Alusani; Balogun, Mohammed O; Nkambule, TTI; Cele, Zamani ED; Msagati, TAM
    Sugarcane bagasse is the major solid waste product of the sugarcane industry. As a plant-derived biomass, it is an attractive environmentally friendly alternative to petroleum-based materials. Being a non-food agriculture product, its use as a raw material is more widely accepted. Sugarcane bagasse is comprised mainly of cellulose, hemicellulose and lignin. The aim of this study was to develop a low-cost anion exchange adsorbent from sugarcane bagasse for the removal of phosphates in aqueous solution. The adsorbent was developed by crosslinking chitosan with cellulose that was extracted from sugarcane bagasse. To obtain cellulose for covalent linkage with chitosan, the bagasse was pretreated with dilute sodium hydroxide and sulphuric acid solutions followed by bleaching with hydrogen peroxide. After this process, the material was modified using chitosan functionalized with epichlorohydrin to obtain the modified bagasse (SCB-CS). SCB-CS was characterized using Fourier transform infrared spectroscopy (FTIR) analysis that indicated the successful reduction in the content of lignin and hemicellulose. The grafting of chitosan derivatives within the matrix of cellulose was confirmed by intense peaks at 1651cm-1 and 1589 cm-1 observed on the modified SCB-CS. SCB-CS was evaluated for its ability to remove phosphates from synthetic waste water and 61.51% removal and an adsorption capacity of 52.3 mg/g, where the initial concentration was 28.36 mg/L at an adsorbent dosage of 0.1 g was achieved.
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    Physico-chemical characterization of polyethylene glycol-conjugated betulinic acid
    (2020-11) Mvango, Sindisiwe; Mthimkhulu, N; Fru, PA; Pilcher, LA; Balogun, Mohammed O
    Betulinic acid (BA) is a naturally occurring plant pentacyclic triterpenoid with activity against cancer and infectious diseases like malaria and AIDS. Its pharmacological activity is limited by low aqueous solubility and bioavailability. Attempts have been made to improve the solubility of BA by conjugation to the water-soluble polymer polyethylene glycol (PEG) but with very limited physico-chemical characterizations. This work presents physico-chemical characterizations of a PEG-BA conjugate using 1H NMR spectroscopy, electron microscopy, DLS and XRD. The NMR data showed successful conjugation through the formation of an amide bond with a 5% drug loading although the appearance of some chemical shift signals were solvent-dependent. TEM images showed a spherical morphology of the conjugate with average diameter of 59.58±4.47 nm.