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Innovations and prospects

Abstract : 4.1 Infant formula (IF) and follow-on (FO) powders are formulated products used for early-life nutrition. Typical processing steps used in the manufacture of IF/FO powdered formulae include batch make-up, heating, homogenization, evaporation and drying. Both IF and FO powdered formulae must be manufactured to the highest safety standards, with increasing requirements for clinically proven nutritional benefits and optimal reconstitution properties, including good visual quality with no sedimentation, free oil, un-reconstituted particles or evidence of flecking. The chapter discusses the drying of IF and FO holistically, taking into account the effects of recipe, wet-processing and dryer configuration on production efficiency and powder quality. In particular, the effects of emulsion quality and viscosity prior to drying are presented as key variables, which illustrate the importance of formulation/recipe on wet-processing and subsequent drying behavior. 4.2 The global lactose-free dairy products market still increasing drives the development of new lines of products by the dairy industry. In this sense, a wide variety of dairy products with lactose-free appeals are available on the market such as pasteurized and UHT milk, yogurt, cheeses, ice-cream, dulce de leche and other dairy products. However few reports describe the effect of lactose hydrolysis on the properties of dried milk powders during production and storage. Lactose hydrolyzed dried milk powder production remains a challenge for the dairy industry because of specific technological problems. Due to the presence of the monosaccharides glucose and galactose, lactose-free powders tend to suffer stickiness, caking and browning during drying and storage. This chapter deals with the consequences of lactose hydrolysis during the production and storage of dried milk powders. 4.3 Camel milk has a composition and properties quite close to human milk. Camel milk’s composition is considered superior to that of bovine milk in terms of its nutritional and therapeutic value. It contains high concentrations of several bioactive compounds that have health benefits. To achieve long-term stability and usability, many dairy-based products and ingredients are dehydrated to powder form. However, such severe heat treatments eventuate in the loss of heat-labile bioactive compounds. Protecting these bioactive compounds during the production of camel milk powder is a challenge for dairy researchers and manufactures. To maintain the activity of such compounds, low-temperature drying operations such as freeze-drying are preferred, and there are many freeze-dried camel milk powder products available on the market. However, due to the limitations of freeze-drying in the production of milk powder, freeze-drying needs to be replaced with other economic drying approaches such as spray drying. However, the application of spray drying in the production of camel milk powder is still in early stages of research, and there are only a few reported studies. This chapter describes the bioactive properties of camel milk and the potential application of spray drying to produce camel milk powder. 4.4 An innovative processing scheme for the production of permeate powders is evaluated in this chapter. It includes an overconcentration step that makes it possible to replace the spray-drying step used in conventional processes. This innovative processing scheme includes: (1) overconcentration of the permeate concentrate from 60 to 80% w/w dry matter (DM) content; (2) granulation of the overconcentrate with powder up to 88% w/w DM; and (3) drying of the granules up to 97% w/w DM. Considering only water removal, the energy savings in comparison to the conventional process were estimated in the range of 10.7 to 23.5%, and even up to 32% when considering the whole production process or the drying step alone. The feasibility of the process was validated at pilot scale, and the results showed that it leads to significant savings in energy and building requirements for a quality of powder at least equivalent to a standard powder produced using conventional technologies. 4.5 Due to the variety and complexity of the fat-filled concentrates to be dried, the dairy industry has been looking over the past 20 years for effective methods, including modeling, in order to predict the drying behavior of dairy products and adjust the outlet gas temperature and humidity. In this chapter, we describe a reliable method based on physicochemical and thermodynamic properties that was developed at INRAE to achieve this objective. It combines two approaches to predict the spray-drying parameters of fat-filled powder: on the one hand, a representative function of the availability of water in the concentrate, depending on its biochemical composition, is provided by a desorption method; on the other hand, the dryer key features (evaporation capacity, air flow rates, configuration) and weather conditions are considered (Schuck, 2013). It makes it possible to obtain a reliable prediction (± 5%) of the inlet air temperature for a given product formulation, and to develop continuous-improvement approaches. 4.6 A novel spray-drying process for the continuous production of probiotics was proposed. Concentrated sweet whey (up to 30% w/w dry matter) was used to both culture and spray dry Propionibacterium freudenreichii ITG P20 and Lactobacillus casei BL23. This process cuts down the steps between culturing and drying (e.g. harvesting, washing, re-suspension), increases the cell population after growth and improves spray-drying productivity and probiotic viability. The mechanisms were explored from the point of view of both bacterial stress resistance and drying process conditions. The hypertonic stress led to overexpression of key stress proteins and the accumulation of intracellular compatible solutes, which contributed to the enhanced multistress tolerance acquisition in hyper-concentrated sweet whey. The presence of protein aggregates and increased concentration of magnesium salt in the matrix may also be involved. The feasibility of scaling up this process was validated at a semi-industrial scale. A multi-stage mild-conditions drying process, coupling spray drying with belt drying and fluid-bed drying, was applied to further improve the probiotic viability to approximately 100% (>109 CFU g−1). This work opens new avenues for the sustainable development of new starter and probiotic preparations with enhanced robustness.
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Submitted on : Thursday, October 1, 2020 - 10:09:45 AM
Last modification on : Tuesday, April 27, 2021 - 3:30:02 PM

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  • HAL Id : hal-02954476, version 1

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Mark A. Fenelon, Eoin G. Murphy, Evandro Martins, Tatiana Lopes Fialho, Pierre Schuck, et al.. Innovations and prospects. Drying in the Dairy Industry From Established Technologies to Advanced Innovations, CRC Press, 296p., 2021, 9781351119504. ⟨hal-02954476⟩

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