Anthocyanin degradation kinetics during thermal and high pressure treatments of raspberries

The effect of combined high temperature and high pressure on the degradation of the four main cyanidin-3-glycosides in raspberries was investigated. Anthocyanin degradation accelerated with increasing temperature as well as with increasing pressure, revealing a synergistic effect of both process variables. Degradation rate constants were estimated using a first order kinetic model. Temperature and pressure dependence of the degradation rate constants were expressed as activation energies and activation volumes according to Arrhenius and Eyring equations, respectively. In search of statistical differences between the E_a-k_ref- and V_a-k_ref-parameters estimated simultaneously, 90% joint confidence regions were constructed. A combined Arrhenius-Eyring model was found suitable to describe the combined temperature-pressure dependence of the degradation rate constants. Cyanidin-3-glucorutinoside showed the slowest degradation in comparison to the other cyanidins. Cyanidin-3-rutinoside experienced the smallest effect of temperature and the strongest effect of pressure compared to the others.     

The stability and degradation of dietary DNA in the gastrointestinal tract of mammals: implications for horizontal gene transfer and the biosafety of GMOs

The fate of dietary DNA in the gastrointestinal tract (GIT) of animals has gained renewed interest after the commercial introduction of genetically modified organisms (GMO). Among the concerns regarding GM food, are the possible consequences of horizontal gene transfer (HGT) of recombinant dietary DNA to bacteria or animal cells. The exposure of the GIT to dietary DNA is related to the extent of food processing, food composition, and to the level of intake. Animal feeding studies have demonstrated that a minor amount of fragmented dietary DNA may resist the digestive process. Mammals have been shown to take up dietary DNA from the GIT, but stable integration and expression of internalized DNA has not been demonstrated. Despite the ability of several bacterial species to acquire external DNA by natural transformation, in vivo transfer of dietary DNA to bacteria in the intestine has not been detected in the few experimental studies conducted so far. However, major methodological limitations and knowledge gaps of the mechanistic aspects of HGT calls for methodological improvements and further studies to understand the fate of various types of dietary DNA in the GIT.     

Physical and sensory characteristics of pork sausages from enzymatically modified blends of lard and rapeseed oil during storage

Physical and sensory characteristic of pork sausages produced from enzymatic interesterified blends of lard and rapeseed oil during storage were evaluated. All three enzymatic interesterified blends (IE90, IE70 and IE50) had ratios of unsaturated to saturated fatty acids within the range of 1.47–2.84 which is favourable for cardiovascular disease risk reduction. Blends of IE90 and IE70 were found to have suitable solid fat content, melting and crystallization profile suitable for sausages production. Sausages were produced from blends of IE90 and IE70 with different muscle types (musculus longissimus dorsi and musculus sternomandibularis) and processing conditions such as cooling rates and final processing temperature. Cooling rate was found to have no significant (P > 0.05) effect on hardness of the sausages throughout storage. Both musculus longissimus dorsi and high final processing temperature of 20 °C increased the hardness of the sausages during storage. In terms of fat particle size distribution, it was found that sausages IE70 had significantly (P < 0.05) lower amount of small fat particles (<4 μm) and higher amount of big fat particles (4–500 μm). This is in agreement with the findings on softer texture of sausages IE70. All the sausages produced from interesterified blends of lard and rapeseed oil had no apparent fat excretion and were rated as having acceptable sensory attributes as compared to reference sausage which was produced from pure lard.     

Peroxidation enhances the biogas production in the anaerobic digestion of biosolids

During the anaerobic digestion of wastewater treatment sludge, commonly called biosolids, an energy rich biogas is formed which is now considered as renewable energy source and widely used for the production of heat and/or electricity. Pre-treatment methods, which achieve a transformation of refractory COD into readily available and soluble BOD, have the potential to enhance the biogas-production. This paper studies several peroxidation techniques for this purpose: the well-known Fenton peroxidation and novel reactions involving peroxymonosulphate (POMS) and dimethyldioxirane (DMDO). The results of the treatments show a considerable increase of COD and BOD in the sludge water, and an increase of the BOD/COD ratio. The biogas production was moreover seen to increase significantly. A maximum increase of 75% was measured with Fenton, while the POMS treatment increased the biogas production by a factor of nearly 2, against an even higher 2.5 for the DMDO treatment. The methane content of the biogas remained between 65 and 70%, thus maintaining its heating value.     

Engagement scolaire, bien-être personnel et autodétermination chez des étudiants à l’université.

This article describes a study that was conducted with a sample of 266 university students and which was guided by two objectives: (a) applying a three-dimensional model of commitment to the academic area, while therein including new motivational considerations and, (b) exploring the nature of the psychological mechanisms by which academic commitment and self-determination interact to predict students’ personal well-being. Exploratory factor analyses allowed the validation of a first version of the Academic Commitment Scale. Correlational and multiple regression analyses permitted the corroboration of the hypothesis pertaining to the positive relationship between academic commitment and personal well-being amongst students. Exploratory and confirmatory analyses led to the corroboration of the hypothesis pertaining to the mediating role of academic commitment in the association between students’ self-determination and personal well-being. The worth of using academic commitment, self-determination, and personal well-being as main targets of investigation while trying to elaborate a model of optimal academic functioning is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)