Martine Bergaentzlé

Bio: Martine Bergaentzlé is an academic researcher from University of Strasbourg. The author has contributed to research in topics: High-performance liquid chromatography & Vitamin. The author has an hindex of 16, co-authored 25 publications receiving 768 citations. Previous affiliations of Martine Bergaentzlé include Centre national de la recherche scientifique.

Effects of processing steps on the phenolic content and antioxidant activity of beer

Abstract: A new analytical method (liquid chromatography-antioxidant, LC-AOx) was used that is intended to separate beer polyphenols and to determine the potential antioxidant activity of these constituents after they were allowed to react online with a buffered solution of the radical cation 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(•+)). Using the LC-AOx method, it was possible to demonstrate that the extent of the antioxidant activity was very much dependent on the phenolic compound considered. The method was also applied to the analysis of beer extracts and allowed the evaluation of their antioxidant activity at different steps of beer processing: brewing, boiling, and fermentation. This study showed that the total antioxidant activity remained unchanged throughout beer processing, as opposed to the polyphenolic content, which showed a 3-fold increase. Hopping and fermentation steps were the main causes of this increase. However, the increase measured after fermentation was attributed to a better extraction of polyphenols due to the presence of ethanol, rather than to a real increase in their content. Moreover, this method allowed the detection of three unknown antioxidant compounds, which accounted for 64 ± 4% of the total antioxidant activity of beer and were individually more efficient than caffeic acid and epicatechin.

Metabolism of Dietary and Microbial Vitamin B Family in the Regulation of Host Immunity

Abstract: Vitamins are micronutrients that have physiological effects on various biological responses, including host immunity. Therefore, vitamin deficiency leads to increased risk of developing infectious, allergic, and inflammatory diseases. Since B vitamins are synthesized by plants, yeasts, and bacteria, but not by mammals, mammals must acquire B vitamins from dietary or microbial sources, such as the intestinal microbiota. Similarly, some intestinal bacteria are unable to synthesize B vitamins and must acquire them from the host diet or from other intestinal bacteria for their growth and survival. This suggests that the composition and function of the intestinal microbiota may affect host B vitamin usage and, by extension, host immunity. Here, we review the immunological functions of B vitamins and their metabolism by intestinal bacteria with respect to the control of host immunity.

Neuronal Lipid Metabolism: Multiple Pathways Driving Functional Outcomes in Health and Disease.

Abstract: Lipids are a fundamental class of organic molecules implicated in a wide range of biological processes related to their structural diversity, and based on this can be broadly classified into five categories; fatty acids, triacylglycerols (TAGs), phospholipids, sterol lipids and sphingolipids. Different lipid classes play major roles in neuronal cell populations; they can be used as energy substrates, act as building blocks for cellular structural machinery, serve as bioactive molecules, or a combination of each. In amyotrophic lateral sclerosis (ALS), dysfunctions in lipid metabolism and function have been identified as potential drivers of pathogenesis. In particular, aberrant lipid metabolism is proposed to underlie denervation of neuromuscular junctions, mitochondrial dysfunction, excitotoxicity, impaired neuronal transport, cytoskeletal defects, inflammation and reduced neurotransmitter release. Here we review current knowledge of the roles of lipid metabolism and function in the CNS and discuss how modulating these pathways may offer novel therapeutic options for treating ALS.

The vitamin content of microalgae used in aquaculture

Abstract: The vitamin content in four Australian microalgae, a Nannochloropsis-like sp., Pavlova pinguis, Stichococcus sp. and Tetraselmis sp., were examined. These were grown under a 12:12 h light:dark regimen (100 μmol photon m−2s−1) and harvested during late-logarithmic phase. Typically, the content showed a two- to three fold range between the species. When expressed on a dry weight basis, the content of ascorbate ranged from 1.3 to 3.0 mg g−1, β-carotene from 0.37 to 1.05 mg g−1, α-tocopherol from 0.07 to 0.29 mg g−1, thiamine from 29 to 109 μg g−1, riboflavin from 25 to 50 μg g−1, total folates from 17 to 24 μg g−1, pyridoxine from 3.6 to 17 μg g−1, cobalamin from 1.70 to 1.95 μg g−1 and biotin from 1.1 to 1.9 μg g−1. Retinol was detected only in Tetraselmis sp. (2.2 μg g−1); any vitamins D2 or D3 were below the detection limit (≤0.45 μg g−1). Nannochloropsis sp. was also grown under a 24:0 h light:dark light cycle and harvested at stationary phase. The content of most vitamins in Nannochloropsis sp. cultures differed significantly, and the degree of variation was similar to that observed between the four species grown under 12:12 h light:dark regimen (100 μmol photon m−2s−1) and harvested during late-logarithmic phase. Thiamine content was also examined in six non-Australian strains commonly used in aquaculture, Chaetoceros muelleri, Thalassiosira pseudonana, Nannochloris atomus, Nannochloropsis oculata, Isochrysis sp. (T.ISO) and Pavlova lutheri. Values (average 61 μg g−1; range 40 to 82) were similar to those in the Australian strains (average 61 μg g−1; range 29 to 109) and increased during stationary phase (average 94 μg g−1; 38 to 131). Comparison of the data with the known nutritional requirements for marine fish species and prawns suggests that the microalgae should provide excess or adequate levels of the vitamins for aquaculture food chains. The data may be used to guide the content of vitamins included in micro-diets developed as replacements for live diets.

Applications of Ozone, Bacteriocins and Irradiation in Food Processing: A Review

Abstract: An article is presented describing the background information on the use of ozone, bacteriocins and irradiation for destroying pathogens in food products. Their effectiveness on some pathogens of importance in food processing systems and issues of concern are highlighted. It could be concluded that although each one has the potential for use as an alternative preservation technology in specific food processing applications, no single method, except irradiation, is likely to be effective against all food spoilage and food poisoning microorganisms in all food matrices. However, the synergistic effect of one of these methods and other 'hurdles' or modes of food preservations could be used to ensure the microbial safety and prevention of the development of undesirable sensory and chemical changes in some food products. Bacteriocins may contribute an additional barrier in the 'hurdle concept' of food safety.