Effect of freezing treatments and yeast amount on sensory and physical properties of sweet bakery products

The frozen bakery market has grown significantly in developed countries over the past decade. Of the available preservation technologies, freezing has been recognized as an excellent method of preserving the quality characteristics of bakery products. The aim of this work was to study the influence of freezing conditions (-20, -30, -40 °C and cryogenic immersion) and yeast content on the sensory and physical properties in the final baked product (Kougelhopf). Physical parameters such as specific volume, moisture, hardness, gas cells distribution and size were determined experimentally. A sensory evaluation (appearance, color, flavor, taste, texture and overall acceptability) was performed in Kougelhopf obtained from fresh and frozen sweet doughs. The experimental results showed that high freezing rates were correlated with more extended damage, yeast activity loss and lower Kougelhopf specific volume. The freezing rate also influenced the gas cells number and size. It was shown that increasing yeast in frozen sweet doughs improved the overall quality of Kougelhopf compensating for the loss of yeast activity during the freezing process. Kougelhopf produced from sweet dough with higher yeast content (DY) presented a higher specific volume, whereas freezing rate increases its hardness. Sensory tests confirmed that experimental results were detected by panelists. © 2012 Elsevier Ltd. All rights reserved.Fil: Meziani, Smail. Coco Lm Company (maison Alsacienne de Biscuiterie); Francia. Laboratoire D'ingénierie Des Biomolécules; FranciaFil: Kaci, Messaouda. Laboratoire D'ingénierie Des Biomolécules; FranciaFil: Jacquot, Muriel. Laboratoire D'ingénierie Des Biomolécules; FranciaFil: Jasniewski, Jordane. Laboratoire D'ingénierie Des Biomolécules; FranciaFil: Ribotta, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; ArgentinaFil: Muller, Jean-Marc. Coco Lm Company (maison Alsacienne de Biscuiterie); FranciaFil: Ghoul, Mohamed. Laboratoire D'ingénierie Des Biomolécules; FranciaFil: Desobry, Stéphane. Laboratoire D'ingénierie Des Biomolécules; Franci

Oxidative Stress Status and its correlation with Redox Status as Measured By An Electrochemical (PAOT®) Methodology: A Pilot Study in Critical COVID-19 Pneumonia Survivors

peer reviewe

A Pilot Study on Oxidative Stress during the Recovery Phase in Critical COVID-19 Patients in a Rehabilitation Facility: Potential Utility of the PAOT ® Technology for Assessing Total Anti-Oxidative Capacity

peer reviewedBackground: Oxidative stress (OS) could cause various COVID-19 complications. Recently, we have developed the Pouvoir AntiOxydant Total (PAOT®) technology for reflecting the total antioxidant capacity (TAC) of biological samples. We aimed to investigate systemic oxidative stress status (OSS) and to evaluate the utility of PAOT®for assessing TAC during the recovery phase in critical COVID-19 patients in a rehabilitation facility. Materials and Methods: In a total of 12 critical COVID-19 patients in rehabilitation, 19 plasma OSS biomarkers were measured: antioxidants, TAC, trace elements, oxidative damage to lipids, and inflammatory biomarkers. TAC level was measured in plasma, saliva, skin, and urine, using PAOT and expressed as PAOT-Plasma, -Saliva, -Skin, and -Urine scores, respectively. Plasma OSS biomarker levels were compared with levels from previous studies on hospitalized COVID-19 patients and with the reference population. Correlations between four PAOT scores and plasma OSS biomarker levels were analyzed. Results: During the recovery phase, plasma levels in antioxidants ( -tocopherol,  -carotene, total glutathione, vitamin C and thiol proteins) were significantly lower than reference intervals, whereas total hydroperoxides and myeloperoxidase (a marker of inflammation) were significantly higher. Copper negatively correlated with total hydroperoxides (r = 0.95, p = 0.001). A similar, deeply modified OSS was already observed in COVID-19 patients hospitalized in an intensive care unit. TAC evaluated in saliva, urine, and skin correlated negatively with copper and with plasma total hydroperoxides. To conclude, the systemic OSS, determined using a large number of biomarkers, was always significantly increased in cured COVID-19 patients during their recovery phase. The less costly evaluation of TAC using an electrochemical method could potentially represent a good alternative to the individual analysis of biomarkers linked to pro-oxidants

Développement et caractérisation d'un nouveau procédé d'émulsification non dénaturant par transduction piézoélectrique de hautes fréquences

Emulsions are systems containing two immiscible liquids, one dispersed as droplets (dispersed phase) throughout the other (continuous phase). When emulsifier is added, it may interact with the other formulations compounds creating new emulsion properties. Therefore, it becomes difficult to study the role of oil phase alone on emulsion properties. In this thesis, emulsifier free emulsion was developed with high frequency ultrasounds (HFU) generated by piezoelectric ceramic transducer vibrating at 1.7 MHz. pH measurement showed significant decrease and negative electrophoretic mobility showed the accumulation of OH- at oil/water interface leading to droplets stability in the emulsion. Emulsions conductivity showed a decrease of the ions quantity in solution, which indicated formation of positive charge layer around OH- structure. They constituted a double ionic layer around oil particles providing emulsion stability. This study showed a strong correlation between turbidity measurement and proportion of emulsified oil. Unlike standard emulsification methods, emulsions made this process demonstrates stability for 30 days at 37 °C. The use of emulsions without emulsifier made by HFU for vectoring CoQ10 shows a higher cell proliferation in the case of emulsion without emulsifier. A study of emulsions without emulsifer by small angle X-ray scattering (SAXS) and nuclear magnetic resonance (1H NMR) was performed and compared to emulsions containing emulsifiers. NMR analysis showed no interactions between different compounds and the HFU manufacturing process did not cause chemical degradation or neoformed compounds. SAXS showed a thin interface between two phases with different electronic density (water/oil) for emulsions with and without emulsifiers. For emulsion with emulsifiers SAXS showed surfactant micelles diffusion signal which doesn’t appear in the emulsion without emulsifiersLes émulsions représentent une large gamme de produits alimentaires, cosmétiques et pharmaceutiques. Pour assurer leur stabilité, une interface chargée de tensioactif est nécessaire. Cette interface constitue une barrière contre la coalescence mais gène la libération des principes actifs encapsulés. Dans cette thèse, une nouvelle méthode d’émulsification est développée. Elle consiste à utiliser des ultrasons à hautes fréquences (UHF) (1,7MHz) qui permettent d’avoir des émulsions stables sans émulsifiants tout en évitant les effets mécaniques violents de la cavitation acoustique présente aux basses fréquences. L’étude des répartitions granulométriques a montré une diminution significative de la taille des gouttelettes d’huile au cours du temps de traitement par ultrasons de hautes fréquences. Le suivi du pH des émulsions montre une forte diminution et une charge de surface importante des gouttelettes est enregistrée ce qui montre une accumulation d’ions OH- à l’interface l'huile/eau conduisant à la stabilité des gouttelettes dans l'émulsion. La conductivité des émulsions diminue durant l’émulsification traduisant une baisse de la quantité d’ions en solution, ce qui indique la formation de la couche contre ions (charge positive) autour de la structure des OH-. Les résultats montrent une stabilisation électrostatique des émulsions obtenue par la formation d’une double couche ionique autour des gouttelettes d’huile. Contrairement aux procédés d’émulsification standard, les émulsions faites par ce procédé montrent une stabilité de 30 jours à 37°C. L’utilisation des émulsions sans émulsifiant faites par UHF pour la vectorisation de CoQ10 montre une prolifération cellulaire plus élevée que dans le cas des émulsions avec émulsifiant. Une étude approfondie des émulsions sans émulsifiant par diffusion des rayons X aux petits angles (SAXS) et par résonance magnétique nucléaire (RMN) a été réalisée et comparée à des émulsions contenant un ou plusieurs émulsifiants. L’étude SAXS montre clairement l’absence de micelles de tensioactifs pour les émulsions sans émulsifiants et les résultats de la RMN montrent l’absence de la signature des tensioactifs et des phospholipides dans les émulsions faites par ultrasons de hautes fréquences. Par ailleurs, la RMN montre l’absence d’interaction entre des différents constituants de l’émulsion et aussi l’absence de structure néoformée

Development and characterization of a novel nondenaturing emulsification process by high frequencies piezoelectric transduction

Les émulsions représentent une large gamme de produits alimentaires, cosmétiques et pharmaceutiques. Pour assurer leur stabilité, une interface chargée de tensioactif est nécessaire. Cette interface constitue une barrière contre la coalescence mais gène la libération des principes actifs encapsulés. Dans cette thèse, une nouvelle méthode d’émulsification est développée. Elle consiste à utiliser des ultrasons à hautes fréquences (UHF) (1,7MHz) qui permettent d’avoir des émulsions stables sans émulsifiants tout en évitant les effets mécaniques violents de la cavitation acoustique présente aux basses fréquences. L’étude des répartitions granulométriques a montré une diminution significative de la taille des gouttelettes d’huile au cours du temps de traitement par ultrasons de hautes fréquences. Le suivi du pH des émulsions montre une forte diminution et une charge de surface importante des gouttelettes est enregistrée ce qui montre une accumulation d’ions OH- à l’interface l'huile/eau conduisant à la stabilité des gouttelettes dans l'émulsion. La conductivité des émulsions diminue durant l’émulsification traduisant une baisse de la quantité d’ions en solution, ce qui indique la formation de la couche contre ions (charge positive) autour de la structure des OH-. Les résultats montrent une stabilisation électrostatique des émulsions obtenue par la formation d’une double couche ionique autour des gouttelettes d’huile. Contrairement aux procédés d’émulsification standard, les émulsions faites par ce procédé montrent une stabilité de 30 jours à 37°C. L’utilisation des émulsions sans émulsifiant faites par UHF pour la vectorisation de CoQ10 montre une prolifération cellulaire plus élevée que dans le cas des émulsions avec émulsifiant. Une étude approfondie des émulsions sans émulsifiant par diffusion des rayons X aux petits angles (SAXS) et par résonance magnétique nucléaire (RMN) a été réalisée et comparée à des émulsions contenant un ou plusieurs émulsifiants. L’étude SAXS montre clairement l’absence de micelles de tensioactifs pour les émulsions sans émulsifiants et les résultats de la RMN montrent l’absence de la signature des tensioactifs et des phospholipides dans les émulsions faites par ultrasons de hautes fréquences. Par ailleurs, la RMN montre l’absence d’interaction entre des différents constituants de l’émulsion et aussi l’absence de structure néoforméesEmulsions are systems containing two immiscible liquids, one dispersed as droplets (dispersed phase) throughout the other (continuous phase). When emulsifier is added, it may interact with the other formulations compounds creating new emulsion properties. Therefore, it becomes difficult to study the role of oil phase alone on emulsion properties. In this thesis, emulsifier free emulsion was developed with high frequency ultrasounds (HFU) generated by piezoelectric ceramic transducer vibrating at 1.7 MHz. pH measurement showed significant decrease and negative electrophoretic mobility showed the accumulation of OH- at oil/water interface leading to droplets stability in the emulsion. Emulsions conductivity showed a decrease of the ions quantity in solution, which indicated formation of positive charge layer around OH- structure. They constituted a double ionic layer around oil particles providing emulsion stability. This study showed a strong correlation between turbidity measurement and proportion of emulsified oil. Unlike standard emulsification methods, emulsions made this process demonstrates stability for 30 days at 37 °C. The use of emulsions without emulsifier made by HFU for vectoring CoQ10 shows a higher cell proliferation in the case of emulsion without emulsifier. A study of emulsions without emulsifer by small angle X-ray scattering (SAXS) and nuclear magnetic resonance (1H NMR) was performed and compared to emulsions containing emulsifiers. NMR analysis showed no interactions between different compounds and the HFU manufacturing process did not cause chemical degradation or neoformed compounds. SAXS showed a thin interface between two phases with different electronic density (water/oil) for emulsions with and without emulsifiers. For emulsion with emulsifiers SAXS showed surfactant micelles diffusion signal which doesn’t appear in the emulsion without emulsifier

DIFFERENCE IN CUTICLE COMPONENT AND IMMUNOCOMPETENCE IN NURSE AND FORAGER WORKER HONEYBEE (APIS MELLIFERA L)

The aim of this work is to study the difference of physiology between the workerbee nurse and forager (Apis mellifera intermissa). The chosen physiologicalcharacteristics were the component of the cuticle (protein-chitin content) and themeasure of the efficiency of immune system (the total number of haemocytes(THC), the normal haemocytes and the relative mass of fat body). The THC iswidely used as an indicator of cellular immunocompetence of insects. The normalhaemocytes, also referred to immunocytes, indicate the integrity of cellularimmune system. The fat body is an indirect measurement of induced humoralimmunocompetence. The THC and the normal haemocytes were determined by themethod described by Amdam et al., (2004). For the estimation of the cuticularabdominal protein-chitin content, the method described by Berghiche et al., (2007)was employed. The relative mass of fat body was determined using an etherextraction method according to Doums et al., (2002) and Wilson-Rich et al.,(2008).The results show that a considerable percentage of a cuticular protein and adecrease of chitin was observed in nurse compared to forager. The older beesexhibited a strong reduction in the immun parameters

Electrochemical Methodology for Evaluating Skin Oxidative Stress Status (SOSS)

For the purpose of human disease prevention, several methods have been developed, and are still developing, to assess the oxidative stress status (OSS) of individuals. In the present paper, we describe an approach based on electrochemical detection able to evaluate skin oxidative stress status (SOSS) as a PAOT (Pouvoir AntiOxydant Total)-Skin Score®. Normal reference values for the PAOT-Skin Score® were: 0−62.94 (n = 263). Intra- and inter-assay coefficients of variation were, respectively, 12.47 ± 4.29% and 7.0 ± 2.5%. Our technology showed increased skin antioxidant activity following topical application of reduced coeznyme Q10 cream or vitamin C intake as orange juice or supplements. Moreover, we found significant correlations between some blood oxidative stress biomarkers and the PAOT-Skin Score® (γ-tocopherol/α-tocopherol ratio (r = 0.43, p = 0.020); copper (r = −0.42, p = 0.022); copper/zinc ratio (r = −0.49, p = 0.006), and lipid peroxides (r = −0.43, p = 0.002)). In addition to being non−invasive, the present electrochemical methodology is also not expensive, fast, and easy to use

Emulsification by high frequency ultrasound using piezoelectric transducer: Formation and stability of emulsifier free emulsion

International audienceEmulsifier free emulsion was developed with a new patented technique for food and cosmetic applications. This emulsification process dispersed oil droplets in water without any emulsifier. Emulsions were prepared with different vegetable oil ratios 5%, 10% and 15% (v/v) using high frequency ultrasounds generated by piezoelectric ceramic transducer vibrating at 1.7 MHz. The emulsion was prepared with various emulsification times between 0 and 10 h. Oil droplets size was measured by laser granulometry. The pH variation was monitored; electrophoretic mobility and conductivity variation were measured using Zeta-sizer equipment during emulsification process. The results revealed that oil droplets average size decreased significantly (p <0.05) during the first 6 h of emulsification process and that from 160 to 1 mu m for emulsions with 5%, 10% and from 400 to 29 mu m for emulsion with 15% of initial oil ratio. For all tested oil ratios, pH measurement showed significant decrease and negative electrophoretic mobility showed the accumulation of OH- at oil/water interface leading to droplets stability in the emulsion. The conductivity of emulsions showed a decrease of the ions quantity in solution, which indicated formation of positive charge layer around OH- structure. They constitute a double ionic layer around oil particles providing emulsion stability. This study showed a strong correlation between turbidity measurement and proportion of emulsified oil

PAOT-Liquid® Technology: An easy Electrochemical Method for Evaluating Antioxidant Capacity of Wines

Polyphenol compounds present in high quantity in wines are well-known to have potent cardio-protective properties through several biological mechanisms including antioxidant activity [1]. A large number of methods have been developed in the laboratory for evaluating this last mechanism in food matrices. Most of them have, however, the disadvantage of being time consuming and require specific analytical protocols and devices. In the present study, we present the electrochemical PAOT (Pouvoir Antioxydant Total)-Liquid® Technology which can be easily used by winemakers for evaluating antioxidant activity during the wine process. The methodology is based on the measurement of electric potential variation resulting from chemical reactions between wine polyphenols and a free radical mediator M• as source of oxidants. Total antioxidant activity as estimated by the PAOT-Liquid® activity was 6.8 fold higher in red wines (n = 14) when compared to rosé (n = 3) and white (n = 3) wines built in a commercial market. Moreover, PAOT-Liquid® activity was highly correlated with total polyphenols content (TPC) of all wines (r = 0.9540, p < 0.0001) and the classical DPPH (2,2-diphenyl-1-picryhydrazyl) assay very which is often used for evaluating antioxidant capacity of food matrices (r = 0.9102, p < 0.0001)

PAOT-Liquid^® Technology: An Easy Electrochemical Method for Evaluating Antioxidant Capacity of Wines

Polyphenol compounds present in high quantity in wines are well-known to have potent cardio-protective properties through several biological mechanisms including antioxidant activity [1]. A large number of methods have been developed for evaluating the antioxidant capacity of food matrices. Most of them have, however, the disadvantage of being time consuming and require specific analytical protocols and devices. In the present study, we present the electrochemical PAOT (Pouvoir Antioxydant Total)-Liquid® Technology which can be easily used by winemakers for evaluating antioxidant activity of wine during all steps of making process. The methodology is based on the measurement of electric potential variation resulting from chemical reactions between wine polyphenols and a free radical mediator M• as source of oxidants. Total antioxidant activity as estimated by the PAOT-Liquid® activity was 6.8 fold higher in red wines (n = 14) when compared to rosé (n = 3) and white (n = 3) wines bought in a commercial market. Moreover, PAOT-Liquid® activity was highly correlated with total polyphenols content (TPC) of all wines (r = 0.9540, p &lt; 0.0001) and the classical DPPH (2,2-diphenyl-1-picryhydrazyl) assay which is often used for evaluating antioxidant capacity of food matrices (r = 0.9102, p &lt; 0.0001)