Interpreting press coverage of South Africa’s post-apartheid “obesity epidemic”:
- Authors: Vincent, Louise , Malan, Chantelle
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141866 , vital:38011 , DOI: 10.1080/21604851.2015.1015397
- Description: This study examines news reporting on South Africa’s alleged “obesity” epidemic between 1997 and 2012. Results indicate that fatness is equated with disease, crisis, and dysfunction and the fat black body is singled out for particular attention as a social problem. News reporting on fat in South Africa uncritically takes up the views of sources with commercial interests who are presented as “experts” on fat. Their interpretations of the fat black body as a social problem are influenced by the imperative of new markets for products that are to be found principally in the ranks of the post-apartheid black middle class.
- Full Text:
- Date Issued: 2016
The inhibitory effects of various substrate pre-treatment by-products and wash liquors on mannanolytic enzymes
- Authors: Malgas, Samkelo , Van Dyk, J Susan , Abboo, Sagaran , Pletschke, Brett I
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66156 , vital:28911 , https://doi.org/10.1016/j.molcatb.2015.11.014
- Description: publisher version , Biomass pre-treatment is essential for achieving high levels of bioconversion through increased accessibility of hydrolytic enzymes to hydrolysable carbohydrates. However, pre-treatment by-products, such as sugar and lignin degradation products, can negatively affect the performance of hydrolytic (mannanolytic) enzymes. In this study, two monomeric sugars, five sugar degradation products, five lignin derivatives and four liquors from biomass feedstocks pre-treated by different technologies, were evaluated for their inhibitory effects on mannanolytic enzymes (α-galactosidases, β-mannanases and β-mannosidases). Lignin derivatives elicited the greatest inhibitory effect on the mannanolytic enzymes, followed by organic acids and furan derivatives derived from sugar degradation. Lignin derivative inhibition appeared to be as a result of protein–phenolic complexation, leading to protein precipitating out of solution. The functional groups on the phenolic lignin derivatives appeared to be directly related to the ability of the phenolic to interfere with enzyme activity, with the phenolic containing the highest hydroxyl group content exhibiting the greatest inhibition. It was also demonstrated that various pre-treatment technologies render different pre-treatment soluble by-products which interact in various ways with the mannanolytic enzymes. The different types of biomass (i.e. different plant species) were also shown to release different by-products that interacted with the mannanolytic enzymes in a diverse manner even when the biomass was pre-treated using the same technology. Enzyme inhibition by pre-treatment by-products can be alleviated through the removal of these compounds prior to enzymatic hydrolysis to maximize enzyme activity.
- Full Text: false
- Date Issued: 2016