Pierre Schuck

Handbook of food powders: processes and properties

Many food ingredients are supplied in powdered form, as reducing water content increases shelf life and aids ease of storage, handling and transport. Powder technology is therefore of great importance to the food industry. The Handbook of food powders explores a variety of processes that are involved in the production of food powders, the further processing of these powders and their functional properties. Part one introduces processing and handling technologies for food powders and includes chapters on spray, freeze and drum drying, powder mixing in the production of food powders and safety issues around food powder production processes. Part two focusses on powder properties including surface composition, rehydration and techniques to analyse the particle size of food powders. Finally, part three highlights speciality food powders and includes chapters on dairy powders, fruit and vegetable powders and coating foods with powders. The Handbook of food powders is a standard reference for professionals in the food powder production and handling industries, development and quality control professionals in the food industry using powders in foods, and researchers, scientists and academics interested in the field. Explores the processing and handling technologies in the production of food powders. Examines powder properties, including surface composition, shelf life, and techniques used to examine particle size. Focusses on speciality powders such as dairy, infant formulas, powdered egg, fruit and vegetable, and culinary and speciality products.

Shape, shell, and vacuole formation during the drying of a single concentrated whey protein droplet.

The drying of milk concentrate droplets usually leads to specific particle morphology influencing their properties and their functionality. Understanding how the final shape of the particle is formed therefore represents a key issue for industrial applications. In this study, a new approach to the investigation of droplet-particle conversion is proposed. A single droplet of concentrated globular proteins extracted from milk was deposited onto a hydrophobic substrate and placed in a dry environment. Complementary methods (high-speed camera, confocal microscopy, and microbalance) were used to record the drying behavior of the concentrated protein droplets. Our results showed that whatever the initial concentration, particle formation included three dynamic stages clearly defined by the loss of mass and the evolution of the internal and external shapes of the droplet. A new and reproducible particle shape was related in this study. It was observed after drying a smooth, hemispherical cap-shaped particle, including a uniform protein shell and the nucleation of an internal vacuole. The particle morphology was strongly influenced by the drying environment, the contact angle, and the initial protein concentration, all of which governed the duration of the droplet shrinkage, the degree of buckling, and the shell thickness. These results are discussed in terms of specific protein behaviors in forming a predictable and a characteristic particle shape. The way the shell is formed may be the starting point in shaping particle distortion and thus represents a potential means of tuning the particle morphology.

To What Extent Do Whey and Casein Micelle Proteins Influence the Morphology and Properties of the Resulting Powder

How the type of protein influences particle morphology remains a hot topic of debate. In this study we focused on the drying behavior of two major milk protein types; that is, whey protein and native micellar caseins. To improve understanding of the role of each protein in the particle-forming mechanisms, seven mixtures containing different whey proteins to caseins ratios were investigated. A monodisperse spray dryer (MDSD) was used to produce uniform particles by drying monodispersed droplets in a hot, dry air flow. Single particles were also obtained from the same material using single droplet drying in a pendant configuration. Powders were characterized according to their physical characteristics and their rehydration properties. It was demonstrated that particle morphology was mainly governed by the type of protein matrix, almost regardless of the drying kinetics, which differed considerably between MDSD and single droplet drying. Controlling product formulation thus represents a potential means by which to tune particle morphology and therefore the functional properties of powder.

Simulating Industrial Spray-Drying Operations Using a Reaction Engineering Approach and a Modified Desorption Method

A predictive tool using a thermodynamic approach has recently been developed to determine several important gas-feed parameters for industrial spray-drying processes. In this approach, a desorption behavior of materials was evaluated and the behavior was linked with overall heat and mass balances over the dryer. Using the desorption behavior of materials and the overall heat and mass balances, a spray-drying software SD2P® was designed at the Institut National de la Recherche Agronomique (INRA) in France. The SD2P® software allows the prediction of optimal inlet drying air temperatures with acceptable accuracy (95–99% accuracy) for spray drying of dairy products. In order to predict detailed quality parameters and stickiness behavior of a product during processing, the reaction engineering approach (REA) was combined with a modified desorption method. A traditional experimental setup is replaced with a new setup, which is described in this article. Drying kinetics parameters were predicted using this new setup. Important gas-feed parameters were predicted using the 1D simulation-based software and compared with SD2P® predictions and are reported here.

Changes in Functional Properties of Milk Protein Powders: Effects of Vacuum Concentration and Drying

Vacuum concentration and dehydration by spray drying are valuable techniques for the evaporation of water and are used to stabilize most dairy ingredients. In view of the increasing development of filtration processes, there is a need for the dairy industry to improve their understanding of the effects of controlling these processes on the concentration and spray drying and hence on the quality of protein powders. Several authors have reported that proteins have an important role in the mechanisms of water transfer during drying and rehydration. The residence time of the droplet and the powder in the spray dryer is so short that it is very difficult to implement studies on the mechanisms of the structural changes in the protein without fundamental research into the process/product interactions. However, many studies have reported that the main structural and functional modifications occur before spray drying; that is, during concentration by vacuum evaporation and heat treatment. Following an extensive introduction focusing on dairy powders, this article covers three significant areas: an overview of the main dairy powder processes, the properties of these powders, and the effects of the processes on powder quality.

Hyperconcentrated Sweet Whey, a New Culture Medium That Enhances Propionibacterium freudenreichii Stress Tolerance

ABSTRACT Propionibacterium freudenreichii is used as a cheese-ripening starter and as a probiotic. Its reported physiological effects at the gut level, including modulation of bifidobacteria, colon epithelial cell proliferation and apoptosis, and intestinal inflammation, rely on active metabolism in situ. Survival and activity are thus key factors determining its efficacy, creating stress adaptation and tolerance bottlenecks for probiotic applications. Growth media and growth conditions determine tolerance acquisition. We investigated the possibility of using sweet whey, a dairy by-product, to sustain P. freudenreichii growth. It was used at different concentrations (dry matter) as a culture medium. Using hyperconcentrated sweet whey led to enhanced multistress tolerance acquisition, overexpression of key stress proteins, and accumulation of intracellular storage molecules and compatible solutes, as well as enhanced survival upon spray drying. A simplified process from growth to spray drying of propionibacteria was developed using sweet whey as a 2-in-1 medium to both culture P. freudenreichii and protect it from heat and osmotic injury without harvesting and washing steps. As spray drying is far cheaper and more energy efficient than freeze-drying, this work opens new perspectives for the sustainable development of new starter and probiotic preparations with enhanced robustness. IMPORTANCE In this study, we demonstrate that sweet whey, a dairy industry by-product, not only allows the growth of probiotic dairy propionibacteria, but also triggers a multitolerance response through osmoadaptation and general stress response. We also show that propionibacteria accumulate compatible solutes under these culture conditions, which might account for the limited loss of viability after spray drying. This work opens new perspectives for more energy-efficient production of dairy starters and probiotics.

Structural markers of the evolution of whey protein isolate powder during aging and effects on foaming properties

The market for dairy powders, including high added-value products (e.g., infant formulas, protein isolates) has increased continuously over the past decade. However, the processing and storage of whey protein isolate (WPI) powders can result in changes in their structural and functional properties. It is therefore of great importance to understand the mechanisms and to identify the structural markers involved in the aging of WPI powders to control their end use properties. This study was performed to determine the effects of different storage conditions on protein lactosylations, protein denaturation in WPI, and in parallel on their foaming and interfacial properties. Six storage conditions involving different temperatures (θ) and water activities (aw) were studied for periods of up to 12mo. The results showed that for θ≤20°C, foaming properties of powders did not significantly differ from nonaged whey protein isolates (reference), regardless of the aw. On the other hand, powders presented significant levels of denaturation/aggregation and protein modification involving first protein lactosylation and then degradation of Maillard reaction products, resulting in a higher browning index compared with the reference, starting from the early stage of storage at 60°C. These changes resulted in a higher foam density and a slightly better foam stability (whisking) at 6mo. At 40°C, powders showed transitional evolution. The findings of this study will make it possible to define maximum storage durations and to recommend optimal storage conditions in accordance with WPI powder end-use properties.

Energy Consumption in the Processing of Dairy and Feed Powders by Evaporation and Drying

Vacuum concentration and drying are valuable techniques for the removal of water and the resulting stabilization of most dairy and feed ingredients. In this study, we present methodology to calculate and compare the energy consumption for the production of dairy and feed powders at different processing stages of the dehydration process. The results show that the energy costs to produce 1 kg of dairy and feed powders were 6,120 and 20,232 kJ · kg−1 powder for pregelatinized starch and soy protein concentrate, respectively. For dairy products, the values were 9,072 and 15,120 kJ · kg−1 for fat-filled and demineralized whey powders, respectively. According to the type of product (biochemical composition, ratio of bound and free water) and process (demineralization, vacuum evaporation, lactose crystallization, roller and spray drying), the energy consumption for the production of powders could be calculated. These findings could be valuable for studies focusing on improvement of energy efficiency for dairy and feed processes.

Infant formula powders

Human milk is the best food for all human infants. However, there are situations where the mother cannot or does not want to breastfeed. In such situations, an alternative food is necessary: an infant formula. The aim of infant formulae is thus to try to mimic the composition and function of breast milk and to provide a formula-fed infant with the same growth and development as an exclusively breastfed infant. Considerable progress has been made in recent years in this field. We provide here a general overview of the infant formula market, formula composition, classification and production.

Lactose and Oligosaccharides | Lactose: Crystallization

Lactose crystallization is a key step in the manufacture of whey powders and derivates. Both crystal size and mass of the crystals produced affect the subsequent step of spray-drying and whey powder quality. Consequently, it is essential to control crystallization kinetics, crystal quality, and how these properties are affected by whey components. At an industrial scale, high lactose supersaturations prevail during the crystallization step so that nucleation, crystal growth, and mutarotation occur simultaneously. A kinetic model combining the first-order differential equations representing the three consecutive steps of lactose crystallization, namely, mutarotation, nucleation, and crystal growth, has been developed. Kinetic expressions of each of these steps have been combined into one single model that successfully predicts the different stages of lactose crystallization kinetics and the impacts of process parameters (total solids, seeding, temperature). Following an introduction to spray-drying of whey, this article on lactose crystallization covers different areas: principles and kinetics of lactose crystallization; description of the different steps; and effects of the factors related to the operating conditions on the quality of lactose crystallization and the quality of the whey and derivate powders produced.