Effect of Maltodextrin Reduction and Native Agave Fructans Addition on the Rheological Behavior of Spray-Dried Juices

Agave fructans have thermal protective and encapsulating properties as well as technological functions as stabilizers. The effect of the combination of maltodextrin 10% [w/v] and native agave fructans in concentrations of 0, 2, and 4% [w/v] on the rheological properties and microstructure, of spray-dried chayote, carrot, mango and pineapple powders was evaluated. The flow behavior was analyzed in a simple shear flow and low-cutting speed in the range of 5–200 s−1. The experimental data of fresh or reconstituted juices were fitted to different flow models such as Newtonian, Bingham, and Ostwald-de-Waele. The flow behavior of all juices can be described by the Bingham model with low plastic viscosities; the addition of fructans and the step of spray drying had no significant influence on the plastic viscosity of juices as compared to fresh juices

Design of an ohmic reactor to study the kinetics of thermal reactions in liquid products

International audienceAn ohmic reactor was developed at a laboratory-scale to study the kinetics of thermal reactions in liquid products such as milk and infant formula in the UHT domain. Temperature mapping revealed good thermal homogeneity with a maximum difference of 3 °C in the treatment cell. The ohmic reactor enabled determination of the electrical conductivity of the product under the real thermal conditions with a precision of ±15%. Reproducible thermal profiles were obtained with a 2.3% relative variation for the heating phase, 1% for holding and 20% for cooling. The FAST index, giving a global measurement of the extent of the Maillard reaction in dairy products, was used to estimate the reproducibility of a thermal reaction with an average standard deviation of 3.8%. Finally, a semi-empirical model was developed to predict product temperature history during a complete thermal treatment with good adjustment for heating and holding and acceptable adjustment for cooling

Foaming and adsorption behaviour of camel β-casein and α-lactalbumin mixed layers at the air/water interface.

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Foaming and air-water interfacial properties of camel milk proteins compared to bovine milk proteins

International audienceThe objective of this research was to explore the foaming properties of camel and bovine milk and their derived proteins fractions including sodium caseinates, sweet whey, beta-casein, alpha-lactalbumin and beta-lactoglobulin. First, camel and bovine milk proteins were identified by the reversed-phase high-performance liquid chromatography (RP-HPLC) and foaming properties (Foam capacity (FC) and stability (FS)) were analyzed. Afterwards, competitive adsorption of proteins to the air-water interface for both milk protein fractions was characterized using pendant-drop tensiometry parameters and was compared to intrinsic fluorescence results of pure proteins. Experimental results indicated that the maximum FC values were found for camel skim milk, sodium caseinates and beta-casein with higher FS values for bovine beta-casein. Differences in the stability and the highest tensioactive properties of camel beta-casein were explained with the different molecular structure and its higher hydrophobicity when compared to its bovine counterpart. Thus, milk proteins adsorbed layers are mainly affected by the presence of beta-casein which is the first adsorbed and the most abundant protein at the air-water contrary to whey proteins (alpha-lactalbumin and beta-lactoglobulin). These globular proteins are involved in the composition of protein layers at air-water interface, giving higher viscoelastic modulus values, but could not compact well at the interface because of their rigid molecular structure. For camel milk, foaming properties and interfacial behavior are mainly maintained by camel beta-casein due to its higher hydrophobicity compared to bovine beta-casein and the greater exposure of tyrosine residues despite the absence of tryptophan in consistence with the intrinsic fluorescence results. Furthermore, the absence of the beta-lactoglobulin leads to the dominance of the alpha-lactalbumin at the air-water interface which is characterized by lower hydrophobicity than its bovine counterpart leading to lower viscoelastic modulus values than those of bovine whey, and hence to weaker rheological properties of camel milk protein layer at the air-water interface

Processing of phosphocasein dispersions by dynamic high pressure: Effects on the dispersion physico-chemical characteristics and the binding of α-tocopherol acetate to casein micelles

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Structure et stabilité des protéines sous pression : exemple de la protéine VIH 1 et de la mKO.

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Monitoring changes of high-pressure treated muscle proteins: from in situ fluorescence spectroscopy to functional properties

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Understanding the effect of ionic strength on the pressure denaturation of myofibrillar proteins

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Acid gelation of raw and reconstituted spray-dried dromedary milk: A dynamic approach of gel structuring

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Potentialities and Limits of Some Non-thermal Technologies to Improve Sustainability of Food Processing

International audienceIn the whole food production chain, from the farm to the fork, food manufacturing steps have a large environmental impact. Despite significant efforts made to optimize heat recovery or water consumption, conventional food processing remains poorly efficient in terms of energy requirements and waste management. Therefore, in the few last decades, much research has focused on the development of alternative non-thermal technologies. Some of them, such as membrane separation processes, hydrostatic or dynamic high pressure, dense phase or high-pressure carbon dioxide, and pulsed electric fields (PEFs) have been extensively studied for cold pasteurization, concentration, extraction, or food functionalization. However, it is still difficult to evaluate the actual advantages or limits of these innovative processing technologies to replace conventional processes. Thus, the overall aim of this paper is to present an overview of the most relevant studies dealing with the potentialities and limits of these non-thermal technologies to improve sustainability of food processing. After a brief presentation of the physical principles of these technologies, the paper illustrates how these technologies could play a decisive role for sustainable food preservation or valorization of raw materials and by-products