Cooperative Agropur

St. John's, Canada

Cooperative Agropur

St. John's, Canada
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Geagea H.,Laval University | Gomaa A.,Laval University | Gomaa A.,National Research Center of Egypt | Remondetto G.,Cooperative Agropur | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2017

The protective effect of whey proteins on phages of lactic acid bacteria during heat treatment limits the recycling of whey proteins into cheese. To investigate this protective effect, we used lactoferrin (LF) as a whey protein model as a result of its unique physicochemical properties and its antiviral activity. First, the thermal inactivation of lactococcal thermoresistant virulent phage P1532 was measured in LF at 95 °C and under different pH values. Phage inactivation results revealed a strong protective effect of LF on P1532 phage at pH 5 but none at pH 7. The structural conformational changes of LF were then monitored by Fourier transform infrared and circular dichroism spectroscopies. Spectroscopic analysis showed that LF was unfolded after heating at pH 7, while it preserved its tertiary and secondary structures when heated at pH 5. There is a direct correlation between the thermal stability of LF and its ability to protect P1532 phage from heat treatment. © 2017 American Chemical Society.


Alvarez P.A.,Wk Kellogg Institute | Emond C.,Laval University | Gomaa A.,Laval University | Gomaa A.,National Research Center of Egypt | And 2 more authors.
Journal of Food Science | Year: 2015

Whey proteins are now far more than a by-product of cheese processing. In the last 2 decades, food manufacturers have developed them as ingredients, with the dairy industry remaining as a major user. For many applications, whey proteins are modified (denatured) to alter their structure and functional properties. The objective of this research was to study the influence of 85 to 100 °C, with protein concentration of 8% to 12%, and treatment times of 5 to 30 min, while measuring rheological properties (storage modulus, loss modulus, and complex viscosity) and aggregation (intermolecular beta-sheet formation) in dispersions of whey protein concentrate (WPC). A Box-Behnken Response Surface Methodology modeled the heat denaturation of liquid sweet WPC at 3 variables and 3 levels. The model revealed a very significant fit for viscoelastic properties, and a lesser fit for protein aggregation, at temperatures not previously studied. An exponential increase of rheological parameters was governed by protein concentration and temperature, while a modest linear relationship of aggregation was governed by temperature. Models such as these can serve as valuable guides to the ingredient and dairy industries to develop target products, as whey is a major ingredient in many functional foods. © 2015 Institute of Food Technologists®.


Gaudreau H.,Institute of Nutrition and Functional Foods INAF | Gaudreau H.,Laval University | Champagne C.P.,Institute of Nutrition and Functional Foods INAF | Champagne C.P.,Agriculture and Agri Food Canada | And 7 more authors.
Food Research International | Year: 2016

Exposure to oxygen can cause a decrease in growth rates or a complete inhibition of growth of oxygen-sensitive probiotic bacteria. A recent study in our laboratory demonstrated that the growth of an oxygen-sensitive strain, Lactobacillus helveticus, was stimulated, under aerobic conditions, when the culture medium was enriched with green tea extracts (GTE). However, information on the mechanism by which GTE influenced the growth, in the presence of oxygen, of that strain is limited. In the present work, the effects of GTE concentrations (to 2000 μg/mL) and exposure to oxygen on maximal populations of L. helveticus R0052 cells and bacterial lipids were evaluated using viable counts, infrared spectroscopy and gas chromatography analyses. Supplementation of the culture medium with 0 to 500 μg/mL GTE did not have an effect on the populations reached under microaerophilic conditions and on bacterial lipid structure and composition. However, at 2000 μg/mL GTE, high population levels were reached under microaerophilic conditions concomitant with an increase in lipid order and with important changes in fatty acid composition of the bacterial lipids. Interactions between GTE components and bacterial lipids were shown by spectroscopic results. Moreover, bacterial cells have adapted to the presence of 2000 μg/mL GTE in the growth medium by changing their lipid composition. To the best of our knowledge, this work is the first to establish a relationship between the effects of GTE at 2000 μg/mL on bacterial cell's lipids and a stimulation of growth under microaerophilic conditions of an oxygen-sensitive strain. © 2016 Elsevier Ltd.


Gaudreau H.,Laval University | Champagne C.P.,Laval University | Champagne C.P.,Agriculture and Agri Food Canada | Remondetto G.E.,Cooperative Agropur | And 2 more authors.
Food Research International | Year: 2013

Oxygen plays a major role in the loss of viability of oxygen-sensitive bacteria. Antioxidant compounds, such as catechins, could be used to limit negative effects of oxygen exposure on bacteria during their growth and storage in food products. The objective of the present study was to measure the effects of different concentrations of (+)-catechin hydrate, green tea epigallocatechin gallate and green tea extracts (GTE) on the growth of probiotic strains with different oxygen sensitivities: Bifidobacterium longum ATCC 15708, B. longum subsp infantis ATCC 15697 and Lactobacillus helveticus R0052. Redox potential (ORP) measurements of the culture medium as well as Fourier-transform infrared (FTIR) spectroscopy analyses on bacterial cells were carried out to evaluate the effects of GTE supplementation. Results obtained showed that medium enrichment with catechins did not stimulate the growth of the two bifidobacteria. However, the growth of L. helveticus was greatly enhanced, under aerobic conditions, by supplementation of the medium with GTE. This growth-promoting effect could be due, in part, by the reduction of the initial ORP value of the medium following addition of GTE. Moreover, the differences in the FTIR spectral region corresponding to fatty acids observed suggest an effect of GTE also on the lipids of the bacterial cell membrane. Thus, GTE supplementation could be used to limit oxygen toxicity on specific probiotic strains but the growth-promoting effect seems to be strain-dependent. © 2012 Elsevier Ltd.


Gaudreau H.,Laval University | Champagne C.P.,Laval University | Champagne C.P.,Agriculture and Agri Food Canada | Remondetto G.E.,Cooperative Agropur | And 3 more authors.
Journal of Functional Foods | Year: 2016

Probiotics and green tea extracts (GTE) have numerous potential health benefits. GTE had also positive effects on the survival of some probiotic bacteria in food products or during exposure to gastrointestinal conditions. In this study, Lactobacillus helveticus cells and GTE were co-encapsulated in calcium pectinate microparticles (MP). MP's characteristics and their ability to protect cells under gastrointestinal conditions were investigated. Small spherical MP having antioxidant activities and high bacterial cells and polyphenol contents were produced. The coating of these MP with whey proteins was an efficient way to protect cells from conditions encountered in the upper part of the gastrointestinal tract. The co-encapsulation of bacteria with 1000 µg/mL GTE provided an additional protection to the cells in gastric conditions. This study indicates that whey protein-coated pectinate MP could be a new carrier for the combined delivery of viable probiotic cells and GTE to the lower part of the gastrointestinal tract. © 2016


Zorilla R.,Laval University | Liang L.,Laval University | Remondetto G.,Cooperative Agropur | Subirade M.,Laval University
Dairy Science and Technology | Year: 2011

Epigallocatechin-3-gallate (EGCG), an antioxidant present in green tea, could play an important role in the prevention of cancer. However, its bioavailability is low due to its instability in gastrointestinal environment. β-Lactoglobulin (β-Lg), the major protein in whey, is known for its capacity to bind bioactive molecules and could protect them from oxidation. Interaction between β-Lg and EGCG was investigated at pH 7.0 and 4.0 using fluorescence and Fourier transform infrared spectroscopy, and its impact on EGCG antioxidant activity was determined using the ferric-reducing antioxidant power method. EGCG bound to native or heat-denatured β-Lg by hydrogen bonding and possibly hydrophobic interaction at pH 7.0 and 4.0. The affinity of EGCG for heat-denatured β-Lg at pH 7.0 was greater than for native β-Lg and greater than its affinity for the protein in either state at pH 4.0. Complexing with β-Lg decreased the antioxidant activity of EGCG under all conditions investigated. However, the protein provided limited protection of EGCG against degradation over time, the heat-denatured form being slightly more effective at pH 7.0. This study provides insight into the characteristics of β-Lg binding with a flavonoid and its impact on the antioxidant activity of flavonoids in food systems. © INRA and Springer Science+Business Media B.V. 2011.


PubMed | Cooperative Agropur, Laval University and National Research Center of Egypt
Type: | Journal: International journal of food microbiology | Year: 2015

The incorporation of whey protein concentrates (WPC) into cheese is a risky process due to the potential contamination with thermo-resistant phages of lactic acid bacteria (LAB). Furthermore, whey proteins can protect phages during heat treatment, thereby increasing the above risk. The main objective of this work was to understand this protective effect in order to better control LAB phages and maximize whey recycling in the cheese industry. First, the inactivation of a previously characterized thermo-resistant lactococcal virulent phage (P1532) was investigated at 95 C in WPC, in individual whey components -lactoglobulin, -lactalbumin, and bovine serum albumin as well as under different heat and pH conditions. The structural changes of the tested proteins were also monitored by transmission FTIR spectroscopy. Phage inactivation results indicated that the protective effect of whey proteins was pH and time dependent at 95 C and was not restricted to one component. FTIR spectra suggest that the protection is related to protein molecular structures and to the level of protein aggregates, which was more pronounced in acidic conditions. Moreover, the molecular structure of the three proteins tested was differently influenced by pH and the duration of the heat treatment. This work confirms the protective effect of WPC on phages during heat treatment and offers the first hint to explain such phenomenon. Finding the appropriate treatment of WPC to reduce the phage risk is one of the keys to improving the cheese manufacturing process.


Geagea H.,University Laval | Gomaa A.I.,University Laval | Gomaa A.I.,National Research Center of Egypt | Remondetto G.,Cooperative Agropur | And 2 more authors.
International Journal of Food Microbiology | Year: 2015

The incorporation of whey protein concentrates (WPC) into cheese is a risky process due to the potential contamination with thermo-resistant phages of lactic acid bacteria (LAB). Furthermore, whey proteins can protect phages during heat treatment, thereby increasing the above risk. The main objective of this work was to understand this protective effect in order to better control LAB phages and maximize whey recycling in the cheese industry. First, the inactivation of a previously characterized thermo-resistant lactococcal virulent phage (P1532) was investigated at 95. °C in WPC, in individual whey components β-lactoglobulin, α-lactalbumin, and bovine serum albumin as well as under different heat and pH conditions. The structural changes of the tested proteins were also monitored by transmission FTIR spectroscopy. Phage inactivation results indicated that the protective effect of whey proteins was pH and time dependent at 95. °C and was not restricted to one component. FTIR spectra suggest that the protection is related to protein molecular structures and to the level of protein aggregates, which was more pronounced in acidic conditions. Moreover, the molecular structure of the three proteins tested was differently influenced by pH and the duration of the heat treatment. This work confirms the protective effect of WPC on phages during heat treatment and offers the first hint to explain such phenomenon. Finding the appropriate treatment of WPC to reduce the phage risk is one of the keys to improving the cheese manufacturing process. © 2015 Elsevier B.V.

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