Novel Routes for the Design of Poly((meth)acrylic acid) Containing Polymer Structures by Controlled Radical Polymerization

Easy preparation of specialty polymers containing poly((meth)acrylic acid) Poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) are well-known polymers in a high number of applications because of their pH-responsive nature, their hydrophylic characteristics and for their interaction with metal ions. PAA, high tech material An increasing part of high tech polymer materials introduce P(M)AA as segments in well-defined polymer structures. These can be block copolymers, polymer brushes, star polymers etc., depending on the desired properties and functionalities. PAA segments are therefore combined with other polymers like polyacrylates, polymethacrylates, polystyrene and polyethers. The resulting multi-segment materials combine the main properties of the individual polymers. This opens up many perspectives for new materials with tailored properties. Novel technology… In this Ph.D. research work, a new synthetic route for polymers containing P(M)AA segments has been developed, opening up opportunities for both new products and new processes for existing P(M)AA-containing polymers. Controlled radical polymerization techniques such as RAFT and ATRP were used to synthesize well-defined poly(1-ethoxyethyl(meth)acrylate) (PEE(M)A). This was demonstrated by kinetic data, control of molecular weight and the presence of a narrow molecular weight distribution. Additionally, working examples demonstrate the synthesis of various (co)polymer structures containing PEE(M)A. PEE(M)A is a hydrophobic polymer and is a precursor for P(M)AA. This allows the preparation of P(M)AA-containing polymers under hydrophobic conditions. A simple heating step (> 70 °C) quantitatively transforms PEE(M)A into P(M)AA by release of a gas, leading to an “on-the-spot” conversion of a hydrophobic prepolymer to a hydrophilic polymer. Further on, the combination of ATRP of EEA and the recently popularized copper(I) catalyzed “click” 1,3-dipolar cycloaddition reaction of azides and terminal alkynes was evaluated as a method to synthesize amphiphilic copolymer structures, using a modular approach

Nutrient profile labelling: consumers’ perceptions in Germany and Belgium

Growing consumer interest in food and health has motivated the European food industry to provide more simple information on the nutritional composition of foods. In addition to the traditional back-of-pack nutrition table, simplified front-of-pack labels have been introduced by the food industry to allow consumers making better informed and healthier food choices. In this paper, consumers’ perceptions of simplified nutrition information, namely Guideline Daily Amount (GDA) and Traffic light (TL), in Germany and Belgium are explored. Surveys in Germany (147 respondents) and Belgium (128 respondents) were conducted in 2008. Data were analysed by means of descriptive statistics and regression analysis. In both countries, the GDA is the most widely used simplified nutrition label. Whereas most consumers in Belgium indicate a preference for the GDA, in Germany the Traffic light is favoured most. Regression analyses indicate that the predilection for the different labels is affected by sociodemographic characteristics and perceptions towards the respective labels. European nutrition policy makers should be aware of regional differences regarding the perception of simplified nutrition labels. The challenge for international food industries is therefore to raise awareness of the potential function of simplified labels in making informed and healthy food choices among different European consumer groups.Nutrient profile labelling, Nutrition policy, European food industry, Consumer survey., Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

The nutritional and toxicological value of organic vegetables : consumer perception versus scientific evidence

Purpose - The present study aims to explore and compare consumer perception and scientific evidence related to food quality and food safety aspects of organic versus conventional vegetables. Design/methodology/approach - Primary data on consumer perception were gathered in 2006-2007 through a consumer survey with Flemish adults (n = 529) and compared with scientific evidence from literature. Consumers of organic and conventional vegetables were selected by means of a convenience sampling procedure. Subjects were asked to complete a self-administered questionnaire concerning the perception of the nutritional and toxicological value of organic relative to conventional vegetables. Data processing and analysis included descriptive analysis (frequency distributions), data reduction (Cronbach's alpha test, factor analysis), bivariate analysis (correlations, t-test, ANOVA) and multivariate analysis (stepwise multiple regression). Findings - It was found that organic vegetables are perceived as containing less contaminants and more nutrients, and as such, being healthier and safer compared to conventional vegetables. However, not enough evidence is currently available in the literature to support or refute such a perception, indicating a certain mismatch between consumer perception and scientific evidence. The gap between perception and evidence is larger among older consumers with children. The perception is stronger when the consumption frequency is higher, but is independent of gender, place of residence (rural or urban), education and income level. Also non-users, on average, perceive that organic vegetables have a nutritional and toxicological advantage over conventional vegetables. Research limitations/implications - A non-probability convenience sampling method was applied which limits generalisation of the findings beyond the sample characteristics. Originality/value - This paper is original in comparing consumer perception and scientific facts related to both nutritional and safety aspects of organic versus conventional vegetables

Explaining the effects of a point-of-purchase nutrition-information intervention in university canteens: a structural equation modelling analysis

Background: The importance of canteen meals in the diet of many university students makes the provision of simple point-of-purchase (POP) nutrition information in university canteens a potentially effective way to promote healthier diets in an important group of young adults. However, modifications to environments such as the posting of POP nutrition information in canteens may not cause an immediate change in meal choices and nutrient intakes. The present study aimed at understanding the process by which the POP nutrition information achieved its effects on the meal choice and energy intake, and whether the information was more effective in changing the meal choice of subgroups of university canteen customers. Methods: The POP nutrition-information intervention used a one-group pretest-posttest design. A sample of 224 customers of two university canteens completed the baseline and 6-months follow-up surveys. A multi-group structural equation modelling analysis was used to test mediation effects of individual difference variables (liking, understanding and use of the information, subjective knowledge and attitude) on the energy intake from canteen meals, moderated by the objective nutrition knowledge and motivation to change diet. Results: Significant relations were identified between liking of the information and its use on one hand and a positive effect in attitude towards healthy canteen meals on the other hand. Motivation to change diet and sufficient objective nutrition knowledge were required to maintain a recommended energy intake from canteen meals or to lead to a decrease in energy intake. Participants with greater objective nutrition knowledge had a greater understanding of the POP nutrition information which also resulted in a more effective use of the information. Conclusions: The results suggest that nutrition-information interventions may be more effective when using nutrition information that is generally liked by the target population in combination with an educational intervention to increase objective nutrition knowledge

CHARACTERIZATION OF THE BACILLUS-STEAROTHERMOPHILUS MANGANESE SUPEROXIDE-DISMUTASE GENE AND ITS ABILITY TO COMPLEMENT COPPER-ZINC SUPEROXIDE-DISMUTASE DEFICIENCY IN SACCHAROMYCES-CEREVISIAE

Recombinant clones containing the manganese superoxide dismutase (MnSOD) gene of Bacillus stearothermophilus were isolated with an oligonucleotide probe designed to match a part of the previously determined amino acid sequence. Complementation analyses, performed by introducing each plasmid into a superoxide dismutase-deficient mutant of Escherichia coli, allowed us to define the region of DNA which encodes the MnSOD structural gene and to identify a promoter region immediately upstream from the gene. These data were subsequently confirmed by DNA sequencing. Since MnSOD is normally restricted to the mitochondria in eucaryotes, we were interested (i) in determining whether B. stearothermophilus MnSOD could function in eucaryotic cytosol and (ii) in determining whether MnSOD could replace the structurally unrelated copper/zinc superoxide dismutase (Cu/ZnSOD) which is normally found there. To test this, the sequence encoding bacterial MnSOD was cloned into a yeast expression vector and subsequently introduced into a Cu/ZnSOD-deficient mutant of the yeast Saccharomyces cerevisiae. Functional expression of the protein was demonstrated, and complementation tests revealed that the protein was able to provide tolerance at wild-type levels to conditions which are normally restrictive for this mutant. Thus, in spite of the evolutionary unrelatedness of these two enzymes, Cu/ZnSOD can be functionally replaced by MnSOD in yeast cytosol

A literature-based comparison of nutrient and contaminant contents between organic and conventional vegetables and potatoes

Purpose - The increasing demand for organic foods is explained mainly by consumers' concerns about the quality and safety of foods and their perception that organically produced foods are healthier and safer than conventional foods. Based on internationally available concentration data of organic and conventional vegetables (carrots, tomatoes, lettuce and spinach) and potatoes, the paper aims to investigate the scientific validity of nutrition claims as "no vegetable/potato has higher amounts of nutrient X than organic vegetables/potatoes" and "no vegetable/potato has lower amounts of contaminant Y than organic vegetables/potatoes". Design/methodology/approach - Detailed nutrient and contaminant databases were developed for organic and conventional vegetables separately. Non-parametric (Mann-Whitney test) methods were used to detect significant differences between both types of vegetables. A chi-square test was used to compare the incidence of pesticide residues in organic and conventional vegetables. Findings - From a nutritional and toxicological point of view, organic vegetables and potato in general are not significantly better than conventional vegetables and potatoes. For some nutrients and contaminants organic vegetables and potatoes score significantly better but for others they score significantly worse. Therefore, it becomes difficult to justify general claims indicating a surplus value of organic over conventional vegetables and potatoes. More data from controlled paired studies are needed to reconsider the use of claims for these organic plant foods in the future. Research limitations/implications - Only a limited number of studies comparing the nutrient and/or contaminant concentration of organic and conventional vegetables are available ("paired studies"). Additionally, the majority of the studies are of moderate or poor quality. The implication is that more of those paired studies are heavily needed. Another limitation of the study is the fact that most pesticide residue data originated from the USA, the EU and Australia. Originality/value - So far only few studies compared both nutrient and contaminant contents between organic and conventional plant foods. This paper covers therefore an important, not well-explored research sub area