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Le Touquet – Paris-Plage, France
Le Touquet – Paris-Plage, France

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Michalski M.C.,INSA Lyon | Genot C.,French National Institute for Agricultural Research | Gayet C.,CNIEL | Lopez C.,Agrocampus Ouest | And 7 more authors.
Progress in Lipid Research | Year: 2013

On a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen. © 2013 Elsevier Ltd. All rights reserved.


Bugeat S.,CNIEL | Bugeat S.,French National Institute for Agricultural Research | Bugeat S.,Agrocampus Ouest | Bugeat S.,University Paris - Sud | And 10 more authors.
Food Research International | Year: 2011

Increasing the unsaturated fatty acid (UFA) content in milk fat is of primary importance to improve the long-term health of consumers. However, such changes can affect the crystallization properties of milk triacylglycerols (TAG) and their functional properties. The objectives of this study were to investigate the crystallization properties of milk fat as a function of its FA composition and emulsion droplet size upon storage at refrigerated temperature. UFA-enriched TAG were obtained using cow diet supplemented with linseed oil and compared to control TAG. Homogenization was used to vary the size of emulsion droplets, from 1.7 to 0.2μm. The crystallization properties of TAG were studied using synchrotron X-ray diffraction coupled to differential scanning calorimetry. We characterized the coexistence of several solid fat phases with a liquid phase, the characteristics of which depended on the temperature, FA composition and droplet size. The enrichment in UFA from 29 to 51wt.% led to a decrease in the enthalpy ratio (δHpartial/δHtotal) from 64±4 to 54±4% at 4°C and to the formation of 2L (41.8Å) structure with β1, β'1, and β'2 polymorphic forms while 2L (39.5Å) and 3L (56.6Å) structures with β1, β2, β'1 and β'2 polymorphic forms were formed with control TAG. The size of the emulsion droplets also affected the structural and thermal properties of milk TAG. Such experiments increased the knowledge about the crystallization properties of TAG dispersed in emulsion and will be useful for industrial applications and the development of UFA-enriched dairy products with improved nutritional properties. © 2011 Elsevier Ltd.


Soustre Y.,Cniel | Chesneau C.,Groupe Soparind Bongrain | Marmonier C.,Cniel
Sciences des Aliments | Year: 2011

In France, the consumption of dairy products and the type of dairy products consumed vary with age and gender. However, over the past ten years, overall consumption of dairy products has tended to decline in all population groups, with a substantial drop for milk. Dairy products are sometimes considered to be too rich in fats and saturated fatty acids. However, the dairy product mix offers a wide range of products with varying fat contents. Moreover, milk fat is a complex and interesting fat, composed of specific saturated fatty acids that have no negative impact on health. Moreover there are a number of arguments in favor of a beneficial effect of dairy products on various pathologies. The medium and long-term impact of the decline in consumption of dairy products is yet to be determined. Dairy products are indeed the main source of calcium and are also major contributors of a number of other important micronutrients. © Lavoisier - La photocopie non autorisée esi un délit.


Gayet-Boyer C.,CNIEL | Tenenhaus-Aziza F.,CNIEL | Prunet C.,CNIEL | Marmonier C.,CNIEL | And 5 more authors.
British Journal of Nutrition | Year: 2014

The effects of ruminant (R) trans-fatty acids (TFA) on the risk of CVD are still under debate. It could be argued that the lack of the effect of R-TFA may be the result of the small amount of their intake. Taking into consideration the growing available data from intervention studies, we carried out a systematic review and meta-regression to assess the impact of R-TFA intake levels on changes in the total cholesterol: HDL-cholesterol (TC:HDL-C) ratio. A systematic review of the literature was conducted and thirteen randomised clinical trials were included, yielding a total of twenty-three independent experimental groups of subjects. A univariate random-effects meta-regression approach was used to quantify the relationship between the dose of R-TFA and changes in the TC:HDL-C ratio. To consider several potential modifiers such as subject and dietary characteristics, a multivariate regression analysis was performed. We found no relationship between R-TFA intake levels of up to 4·19 % of daily energy intake (EI) and changes in cardiovascular risk factors such as TC:HDL-C and LDL-cholesterol (LDL-C):HDL-C ratios. In addition, a multivariate regression analysis that included other dietary variables, as well as subject baseline characteristics, confirmed that doses of R-TFA did not significantly influence the changes in the lipid ratio. Our findings showed that doses of R-TFA did not influence the changes in the ratios of plasma TC:HDL-C and LDL-C:HDL-C. These data suggest that TFA from natural sources, at least at the current levels of intake and up to 4·19 % EI, have no adverse effects on these key CVD risk markers in healthy people. © 2014 The Authors.


Velly H.,CNIEL | Velly H.,French National Institute for Agricultural Research | Velly H.,Agro ParisTech | Bouix M.,French National Institute for Agricultural Research | And 12 more authors.
Applied Microbiology and Biotechnology | Year: 2014

This work aimed at characterizing the biochemical and biophysical properties of the membrane of Lactococcus lactis TOMSC161 cells during fermentation at different temperatures, in relation to their freeze-drying and storage resistance. Cells were cultivated at two different temperatures (22 and 30 °C) and were harvested at different growth phases (from the middle exponential phase to the late stationary phase). Bacterial membranes were characterized by determining the fatty acid composition, the lipid phase transition, and the membrane fluidity. Cultivability and acidification activity losses of L. lactis were quantified after freezing, drying, and 3 months of storage. The direct measurement of membrane fluidity by fluorescence anisotropy was linked to lipid composition, and it was established that the cyclopropanation of unsaturated fatty acids with concomitant membrane rigidification during growth led to an increase in the freeze-drying and storage resistance of L. lactis. As expected, cultivating cells at a lower fermentation temperature than the optimum growth temperature induced a homeoviscous adaptation that was demonstrated by a lowered lipid phase transition temperature but that was not related to any improvement in freeze-drying resistance. L. lactis TOMSC161 was therefore able to develop a combined biochemical and biophysical response at the membrane level during fermentation. The ratio of cyclic fatty acids to unsaturated fatty acids (CFA/UFA) appeared to be the most relevant parameter associated with membrane rigidification and cell resistance to freeze-drying and storage. This study increased our knowledge about the physiological mechanisms that explain the resistance of lactic acid bacteria (LAB) to freeze-drying and storage stresses and demonstrated the relevance of complementary methods of membrane characterization. © 2014, Springer-Verlag Berlin Heidelberg.


Bourdichon F.,Danone Inc. | Bourdichon F.,Nestlé | Casaregola S.,French National Institute for Agricultural Research | Farrokh C.,CNIEL | And 16 more authors.
International Journal of Food Microbiology | Year: 2012

Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on "the history of use", "traditional food", or "general recognition of safety". Authoritative lists of microorganisms with a documented use in food have therefore come into high demand. One such list was published in 2002 as a result of a joint project between the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA). The "2002 IDF inventory" has become a de facto reference for food cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature. © 2011 Elsevier B.V.


Velly H.,CNIEL | Fonseca F.,CNIEL | Passot S.,CNIEL | Delacroix-Buchet A.,CNIEL | Bouix M.,CNIEL
Journal of applied microbiology | Year: 2014

AIMS: To investigate the effects of fermentation parameters on the cell growth and on the resistance to each step of the freeze-drying process of Lactococcus lactis subsp. lactis TOMSC161, a natural cheese isolate, using a response surface methodology.METHODS AND RESULTS: Cells were cultivated at different temperatures (22, 30 and 38°C) and pH (5·6, 6·2 and 6·8) and were harvested at different growth phases (0, 3 and 6 h of stationary phase). Cultivability and acidification activity losses of Lc. lactis were quantified after freezing, drying, 1 and 3 months of storage at 4 and 25°C. Lactococcus lactis was not damaged by freezing but was sensitive to drying and to ambient temperature storage. Moreover, the fermentation temperature and the harvesting time influenced the drying resistance of Lc. lactis.CONCLUSIONS: Lactococcus lactis cells grown in a whey-based medium at 32°C, pH 6·2 and harvested at late stationary phase exhibited both an optimal growth and the highest resistance to freeze-drying and storage.SIGNIFICANCE AND IMPACT OF THE STUDY: A better insight on the individual and interaction effects of fermentation parameters made it possible the freeze-drying and storage preservation of a sensitive strain of technological interest. Evidence on the particularly damaging effect of the drying step and the high-temperature storage is presented. © 2014 The Society for Applied Microbiology.


Burgain J.,CNIEL | Burgain J.,CNRS Biomolecular Engineering Laboratory | Scher J.,CNRS Biomolecular Engineering Laboratory | Petit J.,CNRS Biomolecular Engineering Laboratory | And 3 more authors.
Food Hydrocolloids | Year: 2016

Storage is an unavoidable critical phase regarding dairy powder reconstitution abilities, particularly for high casein content powders, which generally present a poor rehydration behavior. The ability of micellar casein powders to completely rehydrate can thus be particularly affected by storage time and temperature. To implement best practices for the optimization of storage conditions, understanding changes occurring is a crucial point. For the first time, biophysical techniques were used to investigate powder surface at the nanoscale. Atomic force microscopy revealed that particle surface became rougher during storage, associated with the formation of hollow zones (around 500 nm) holes when stored for 10 months at 40 °C. Mechanical properties of micellar casein particle surface during powder storage was quantified using AFM nanoindentation. Spatially-resolved force/indentation curves evidenced a significant stiffer surface for aged powder (Young modulus of ~20 GPa) in comparison with the fresh one (~0.2 GPa). These findings were fully consistent with the formation of a crust at the powder surface observed by high-resolution field-emission scanning electron microscopy during powder rehydration. Finally, alterations of the rehydration process can be related to modifications occurring at the particle surface during storage. © 2016 Elsevier Ltd.


PubMed | CNIEL
Type: Journal Article | Journal: Applied microbiology and biotechnology | Year: 2015

This work aimed at characterizing the biochemical and biophysical properties of the membrane of Lactococcus lactis TOMSC161 cells during fermentation at different temperatures, in relation to their freeze-drying and storage resistance. Cells were cultivated at two different temperatures (22 and 30C) and were harvested at different growth phases (from the middle exponential phase to the late stationary phase). Bacterial membranes were characterized by determining the fatty acid composition, the lipid phase transition, and the membrane fluidity. Cultivability and acidification activity losses of L. lactis were quantified after freezing, drying, and 3months of storage. The direct measurement of membrane fluidity by fluorescence anisotropy was linked to lipid composition, and it was established that the cyclopropanation of unsaturated fatty acids with concomitant membrane rigidification during growth led to an increase in the freeze-drying and storage resistance of L. lactis. As expected, cultivating cells at a lower fermentation temperature than the optimum growth temperature induced a homeoviscous adaptation that was demonstrated by a lowered lipid phase transition temperature but that was not related to any improvement in freeze-drying resistance. L. lactis TOMSC161 was therefore able to develop a combined biochemical and biophysical response at the membrane level during fermentation. The ratio of cyclic fatty acids to unsaturated fatty acids (CFA/UFA) appeared to be the most relevant parameter associated with membrane rigidification and cell resistance to freeze-drying and storage. This study increased our knowledge about the physiological mechanisms that explain the resistance of lactic acid bacteria (LAB) to freeze-drying and storage stresses and demonstrated the relevance of complementary methods of membrane characterization.


The effects of ruminant (R) trans-fatty acids (TFA) on the risk of CVD are still under debate. It could be argued that the lack of the effect of R-TFA may be the result of the small amount of their intake. Taking into consideration the growing available data from intervention studies, we carried out a systematic review and meta-regression to assess the impact of R-TFA intake levels on changes in the total cholesterol: HDL-cholesterol (TC:HDL-C) ratio. A systematic review of the literature was conducted and thirteen randomised clinical trials were included, yielding a total of twenty-three independent experimental groups of subjects. A univariate random-effects meta-regression approach was used to quantify the relationship between the dose of R-TFA and changes in the TC:HDL-C ratio. To consider several potential modifiers such as subject and dietary characteristics, a multivariate regression analysis was performed. We found no relationship between R-TFA intake levels of up to 4.19% of daily energy intake (EI) and changes in cardiovascular risk factors such as TC:HDL-C and LDL-cholesterol (LDL-C):HDL-C ratios. In addition, a multivariate regression analysis that included other dietary variables, as well as subject baseline characteristics, confirmed that doses of R-TFA did not significantly influence the changes in the lipid ratio. Our findings showed that doses of R-TFA did not influence the changes in the ratios of plasma TC:HDL-C and LDL-C:HDL-C. These data suggest that TFA from natural sources, at least at the current levels of intake and up to 4.19% EI, have no adverse effects on these key CVD risk markers in healthy people.

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