Assessment of measurement characteristics for rehydration of milk protein based powders

Prevent lumping during hot-water rehydration of lotus rhizome powder by restricted swelling treatment

Lotus rhizome powder (LRP) tends to lump during hot-water rehydration, adversely affecting its edible quality. By utilizing a restricted swelling treatment (ST), where LRP was swollen at a temperature slightly below its onset gelatinization temperature (To), the lumping rate could be substantially reduced from 30.95% to 6.39%. This treatment induced an ordered-disordered structural transition of LRP without compromising its granule morphology and water dispersibility. This transition led to significant increases in thermal transition temperatures and a notable delay in peak pasting time by 86.6 s. These changes effectively delayed the formation of a gelatinous skin surrounding the dry granules, allowing them sufficient time to absorb water and paste completely, thereby preventing lumping. The prevention of lumping was beneficial for obtaining desired viscoelasticity of LRP paste. Conversely, ST treatments conducted at temperatures markedly deviating from To resulted in significantly higher lumping rates, underscoring the importance of carefully controlling the ST temperature.

A narrative review investigating the potential effect of lubrication as a mitigation strategy for whey protein-associated mouthdrying

Whey is consumed by active adults to aid muscle recovery and growth, the general population as a nutritious convenient food, and by older adults to prevent sarcopenia due to its high leucine content. However, whey protein has poor consumer acceptance in this latter demographic, partially due to mouthdrying. This is thought to result from electrostatic interactions between whey and salivary proteins, mucoadhesion to the oral mucosa, and the inherent astringency of acidity. Previous unsuccessful mitigation strategies include viscosity, sweetness and fat manipulation. This literature review reveals support for increasing lubrication to reduce mouthdrying. However, of the 50 papers reviewed, none have proposed a method by which whey protein could be modified as an ingredient to reduce mouthdrying in whey-fortified products. This review recommends the use of modern technologies to increase lubrication as a novel mitigation strategy to reduce mouthdrying, with the potential to increase consumer acceptance.

Valorization of Sour Buttermilk (A Potential Waste Stream): Conversion to Powder Employing Reverse Osmosis and Spray Drying

Reverse osmosis (RO) is known for the economic dewatering of dairy streams without any change in phase. At the household level, surplus milk is fermented and churned to obtain butter, which is subsequently heated to obtain clarified milk fat (ghee). The production of 1 kg ghee generates 15-20 kg sour buttermilk (SBM) as a by-product that is mostly drained. This causes a loss of milk solids and environmental pollution. The processing, preservation and valorization of SBM are quite challenging because of its low total solids (TS) and pH, poor heat stability and limited shelf life. This investigation aimed to transform SBM into a novel dried dairy ingredient. SBM was thermized, filtered, defatted and concentrated at 35 ± 1 °C, employing RO up to 3.62× (12.86%). The RO concentrate was subsequently converted into sour buttermilk powder (SBMP) by employing spray drying. SBMP was further characterized for its physicochemical, reconstitution and functional properties; rheological and morphological characteristics; and amino acid and fatty acid profiling, along with FTIR and XRD spectra. SBMP was "instant soluble-3 s" and exhibited excellent emulsion stability (80.70%), water binding capacity (4.34 g/g of protein), flowability (28.36°) and antioxidant properties. In nutshell, a process was developed for the valorization of sour buttermilk to a novel dairy ingredient by employing reverse osmosis and a spray-drying process.

Unravelling the Influence of Composition and Heat Treatment on Key Characteristics of Dairy Protein Powders Using a Multifactorial Approach

The purpose of this study was to improve understanding of the structural and functional property changes that milk-protein concentrates undergo during production, particularly how the manufacturing route (heat treatment position and intensity), standardization (in osmosed water or ultrafiltrate permeate) and formulation (casein:whey protein (Cas:WP) ratio) influence the physico-chemical characteristics-hygroscopicity, particle size, sphericity, density and evolution of browning during storage. To obtain a comprehensive understanding of the parameters responsible for the distinctive characteristics of different powders, a multifactorial approach was adopted. Hygroscopicity depended mainly on the standardizing solution and to a lesser extent the Cas:WP ratio. The particle size of the heat-treated casein-dominant powders was up to 5 μm higher than for those that had had no heat treatment regardless of the standardizing solution, which also had no influence on the sphericity of the powder particles. The density of the powders increased up to 800 kg·m-3 with a reduced proportion of casein, and lactose and whey proteins participated in browning reactions during storage at 13 °C. In increasing order, the modality of heat treatment, the standardizing solution and the Cas:WP protein ratio influenced the key characteristics. This work is relevant for industrial applications to increase control over the functionalities of powdered products.

Breakage behaviour and functionality of spray-dried agglomerated model infant milk formula: Effect of proteins and carbohydrates content

This study explored the effect of protein content (whey protein and casein) and carbohydrate content (lactose, sucrose, and maltodextrin) on the breakage behaviour and its influence on spray-dried agglomerated model infant milk formula. Whey protein powders were bigger in particle size, weaker in structural strength, and marginally more irregular in shape, which resulted in better rehydration properties but more breakage than pure casein powders. Similarly, sucrose samples had better rehydration properties and higher glass transition temperatures but suffered more breakage than maltodextrin and pure lactose powders because of their bigger particle size. The influence of proteins on breakage was greater than that of carbohydrates. Breakage changed the physical and structural properties of powders, especially for whey protein and sucrose samples, which caused the deterioration of rehydration properties and the decrease in crystallization temperatures. From the perspective of particle breakage, unwanted dairy powder breakage could be controlled by changing powder formulations.

Investigation of breakage behavior and its effects on spray-dried agglomerated whey protein-lactose powders: Effect of protein and lactose contents

Particle breakage of dairy powders occurs easily during many processes, reducing the powder functionality. The characteristics of particles and the applied stress from processing conditions on the particles are 2 main factors that can be manipulated to reduce breakage. In this study, we explored the effect of whey protein and lactose contents on dynamic breakage in agglomerated whey protein-lactose powders to provide useful information, in terms of particle characteristics, for controlling unwanted dairy powder breakage. A series of model agglomerates with different whey protein:lactose ratios were produced under the same spray-drying conditions, through a pilot plant trial. We evaluated physical characteristics, composition, and structure of samples; analyzed dynamic breakage under different mechanical stresses; and investigated the rehydration and water adsorption properties of model powders before and after breakage. The particle size and irregularity of agglomerates with more lactose was significantly higher than of samples that contained more protein. This resulted in higher particle breakage during dynamic breakage for samples with more lactose. The breakage of agglomerates was affected by the moisture content of powders and fatigue, where particle breakage happens when mechanical loads, lower than the strength of particles, occur multiple times. Breakage changed the morphology and surface composition of particles and decreased particle size. It also decreased the dispersibility of powders and increased the wetting time of wettable samples but decreased the wetting time of powders with poor wettability. Breakage accelerated time-dependent crystallization and decreased the crystallization temperature but did not affect the glass transition temperature of samples. Thus, under the same drying conditions, composition of powders significantly affected breakage, mainly by altering the physical properties of their particles, which resulted in deteriorated functionality.

Improving rehydration properties of spray-dried milk protein isolates by supplementing soluble caseins

Spray-dried milk protein isolates (MPIs) are important dairy ingredients but may not have desirable rehydration properties for industrial applications. In the present study, rehydration properties of MPIs were improved by spray-drying MPI dispersions containing different amounts of soluble caseins in the form of derivatized MPI (dMPI). dMPI was prepared by alkalizing MPI dispersions to pH 11.0 and subsequently acidifying to pH 6.8 (the pH-cycle). All the spray-dried MPIs had the similar bulk density (around 0.33 g/cm^-3), composition, size distribution (1-100 µm), and SEM morphology. However, the decrease of hydrodynamic diameter, dissolution of total solids and proteins, and disruption of particles during the dynamic rehydration were accelerated as the dMPI content increased, indicating the improved rehydration properties. The improvement in rehydration properties was not due to the wettability that decreased as the dMPI:MPI mass ratio changed from 0:8 to 8:0, but resulted from the reduced cross-linking of casein micelles on powder surface and the increased surface porosity during the hydration as observed for partially hydrated samples. The present work may assist industrial applications of spray-dried MPIs.

Enhanced rehydration behaviors of micellar casein powder: The effects of high hydrostatic pressure treatments on micelle structures

Natural micellar casein is generally dried into powdered forms for commercial transportation and storage. However, the poor rehydration ability of micellar casein powder critically limited the potential applications due to its dense cross-linked structures caused by colloidal calcium phosphate (CCP). In this study, micellar casein solutions were exposed to a high hydrostatic pressure (HHP) ranging from 100 to 500 MPa and were then freeze dried to produce powders. The effects on the casein micelle structures and the rehydration characteristics including wetting, dispersion and dissolving were comprehensively investigated. The results showed that HHP could induce smaller micelle sizes and significantly increase the free calcium in the reconstituted solution. It demonstrated that the majority of CCP bridges in casein micelles were dissociated, which produced porous powders with loose structures and thus significantly improved rehydration behaviors. 300 MPa was the pressure level that caused the quickest dispersion process and best solubility. Consequently, HHP has potential to be a novel physical technique to potentially modify the protein higher-order structures as well as improve the corresponding functionalities.

Rehydration Properties of Whey Protein Isolate Powders Containing Nanoparticulated Proteins

The rehydration properties of original whey protein isolate (WPIC) powder and spray-dried WPI prepared from either unheated (WPIUH) or nanoparticulated WPI solutions were investigated. Nanoparticulation of whey proteins was achieved by subjecting reconstituted WPIC solutions (10% protein, w/w, pH 7.0) to heat treatment at 90 °C for 30 s with no added calcium (WPIH) or with 2.5 mM added calcium (WPIHCa). Powder surface nanostructure and elemental composition were investigated using atomic force microscopy and X-ray photoelectron spectroscopy, followed by dynamic visualisation of wetting and dissolution characteristics using environmental scanning electron microscopy. The surface of powder particles for both WPIUH and WPIC samples generally appeared smooth, while WPIH and WPIHCa displayed micro-wrinkles with more significant deposition of nitrogen and calcium elements. WPIH and WPIHCa exhibited lower wettability and solubility performance than WPIUH and WPIC during microscopic observation. This study demonstrated that heat-induced aggregation of whey proteins, in the presence or absence of added calcium, before drying increases aggregate size, alters the powder surface properties, consequently impairing their wetting characteristics. This study also developed a fundamental understanding of WPI powder obtained from nanoparticulated whey proteins, which could be applied for the development of functional whey-based ingredients in food formulations, such as nanospacers to modulate protein–protein interactions in dairy concentrates.

Updating insights into the rehydration of dairy-based powder and the achievement of functionality

Dairy-based powder had considerable development in the recent decade. Meanwhile, the increased variety of dairy-based powder led to the complex difficulties of rehydrating dairy-based powder, which could be the poor wetting or dissolution of powder. To solve these various difficulties, previous studies investigated the rehydration of powder by mechanical and chemical methods on facilitating rehydration, while strategies were designed to improve the rate-limiting rehydration steps of different powder. In this review, special emphasis is paid to the surface and structure of the dairy-based powder, which was accountable for understanding rehydration and the rate-limiting step. Besides, the advantage and disadvantage of methods employed in rehydration were described and compared. The achievement of the powder functionality was finally discussed and correlated with the rehydration methods. It was found that the surface and structure of dairy-based powder were decided by the components and production of powder. Post-drying methods like agglomeration and coating can tailor the surface and structure of powder afterwards to obtain better rehydration. The merit of the mechanical method is that it can be applied to rehydrate dairy-based powder without any addition of chemicals. Regarding chemical methods, calcium chelation is proved to be an effective chemical in rehydration casein-based powder.

Production and application of freeze dried biocomposite coating powders from sunflower oil and soy protein or whey protein isolates

Innovative biocomposite coating powders based on soy protein isolate or whey protein isolate, both containing sunflower oil (SO) were fabricated by freeze drying technique. The influences of concentration of SO and using different protein isolate types on the physicochemical, thermal and morphological properties of the powders were investigated. The Fourier transform infrared spectroscopy and thermal analysis revealed that SO interacted with protein isolates through hydrogen bonding resulted a strong network structure of the powders. It was found that amorphous structure and morphology of the powders was not significantly influenced by oil addition. Moisture content and water activity values of SPI powders were found higher than those of WPI. All powders were wettable, and solubility values were in the range of 91-99%. Preservative-free powders were reconstituted and applied to coat sliced cakes, a bakery product. Coating application showed effective protection on textural structure of cake by high moisture preservation ability.

Pouring of Grains onto Liquid Surfaces: Dispersion or Lump Formation?

This study considers the consequences of adding grains to an air-liquid interface from a funnel. Depending on the grain contact angle and liquid surface tension, the interface is found to support a single or multiple layers of grains, forming a granular stack. By continuing to add grains, the stacks grow until either the lower grains disperse in the liquid, or the complete stack breaks free from the surface and sinks as a dry powder lump. Herein, the effects of grain contact angle, density, and size on these processes are studied experimentally, and a theoretical analysis is given. The maximum number of grains contained in a floating stack and its critical depth are observed to increase as the grain size decreases. The maximum number of grains scales with the bond number (Bo) as Bo^-1.82 when stack detachment is observed and with an exponent  -2.0 when grains disperse into the liquid. As a result of these different scaling exponents, a critical bond number above which grains wet and disperse can be identified. Favorable conditions for dispersion are achieved with larger grains and, to a lesser extent, by lower surface tension and contact angle. The critical bond number separating grain dispersion from lump formation increases with an increasing grain contact angle, thus providing a physical justification for increasing grain size with common processes such as granulation or agglomeration. Conversely, a quantitative framework to interpret the limitations in dispersing small grains is proposed, justifying the need for low contact angle or liquids with low surface tensions, both favored by the use of surfactants. The present findings have identified conditions under which lump formation occurs, and hence how these undesired phenomena can be avoided in applications requiring the efficient dispersion of grains across a liquid interface.

Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS): A Novel Approach To Investigate the Wettability of Pharmaceutical Powder Blends

The ability of broadband acoustic resonance dissolution spectroscopy (BARDS) to assess the wettability of powder blends is investigated. BARDS is a novel analytical technology developed on the basis of the change in acoustic phenomena observed when material is added into a solvent under resonance. Addition of solid material to the solvent results in the introduction of gas (air) into the solvent, changing the compressibility of the solvent system, and reducing the velocity of sound in the solvent. As a material is wetted and dissolved, the gas is released from the solvent and resonance frequency is altered. The main purpose of this work is to demonstrate the ability of BARDS to assess differences in the wetting behavior of tablet excipients (microcrystalline cellulose (MCC) and magnesium stearate (MgSt)) and a model drug (metoclopramide hydrochloride) as single component powders and multicomponent powder blends. BARDS acoustic responses showed a prolonged release of gas for the powdered blends with lubricant compared to unlubricated blends. As the elimination of gas from the solvent was assumed to follow first order elimination kinetics, a compressible gas elimination rate constant was calculated from the log plots of the gas volume profiles. The gas elimination rate constant was used as a parameter to compare the release of gas from the powder introduced to the solvent and hence the powder wetting behavior. A lower gas elimination rate constant was measured for lubricated blends compared to nonlubricated blends, suggesting the prolonged hydration of lubricated blends. Standard wetting techniques such as contact angle measurements and wetting time analysis were also used to analyze the blends and confirmed differences in wetting behavior determined by BARDS. The study results demonstrate the capability of BARDS as a rapid, analytical tool to determine the wetting behavior of the pharmaceutical powder blends and the potential of BARDS as a process analytical technology (PAT) tool.