Food processing is intrinsic to modern food systems, yet its role in dietary exposures and health outcomes remains difficult to interpret because prevailing classifications treat processing as a categorical property rather than a quantifiable dietary exposure. The introduction of a transformation-based framework that distinguishes physical and chemical modification of foods (Food Processing Levels, FPL) was further complemented to derive Processed Food Intake (PFI)-based descriptors and quantify cumulative exposure to processing across meals and diets. Studies commonly cited in support of ultra-processed food hypotheses exhibit substantial heterogeneity within and between 'unprocessed' or 'ultra-processed' diets. Across studies, diets classified as UPF result in a wide variation in cumulative processing exposure, while substantial overlap is observed between UPF and non-UPF diets when processing is expressed quantitatively. Item-weighted, energy-weighted and nutrients-weighted PFI descriptors capture graded differences that are obscured by categorical classifications and enable comparison of diets matched for nutritional quality yet differing in processing history. Treating food processing as a continuous dietary exposure provides a reproducible basis for analyzing intervention designs, interpreting experimental outcomes, and designing studies that explicitly test the nutritional and health relevance of food processing.

The agglutination process between the stamens and bee saliva produces bee pollen. Bee pollen contains high nutritional value and distinctive physical characteristics. Thus far, there are no quality standards and analysis techniques for bee pollen worldwide, mainly for stingless bees. This is likely due to the multifloral nature of stingless bees and the difficulty of identifying the plant species they visit at the individual level. This study examined the nutritional value, bioactive components, and physical characteristics of pollen from Indonesian stingless bees. Based on the study, stingless bees in Indonesia are multifloral, with varied nutritional content and active components influenced by the botanical and geographical conditions of the plants they visit. The phenols and flavonoids were detected in almost all stingless bee pollen. Apart from that, some bee pollen contains small amounts of flavonoids, saponins, triterpenoids, and alkaloids. However, steroids are not reported in all bee pollen. The physical characteristics of bee pollen from stingless bees can be observed in its color and microstructure. This further confirms that the bee pollen from stingless bees in Indonesia is multifloral. To better understand the variety of bee pollen types, it is essential to conduct more thorough investigations into the different plant species and the specific traits of stingless bee colonies within their hives. This research will help confirm the diversity that exists among the types of pollen collected by these bees.

There is a growing interest in exploring strategies to obtain plant-based dairy alternatives with desirable technofunctionalities. This study aimed to examine how conventional heating and microbial transglutaminase (MTGase) influence the gelation characteristics of lentil protein isolate (LPI) when combined with whey protein isolate (WPI) or casein micelles (CM). Gel electrophoresis analysis revealed that, during heat treatment, certain fractions in LPI (such as legumin acidic and basic subunits) and nearly all fractions in WPI (including (3-lactoglobulin and alpha-lactalbumin) underwent disulfide-mediated polymerization, contributing to the heat-induced gel formation, while the gelation of CM was hindered during this process. Conversely, some fractions in LPI (specifically the 11S acidic subunit and 7S vicilins), as well as nearly all CM fractions, were involved in MTGaseinduced cross-linking, while this cross-linking reaction was hindered in WPI. Heat-treated LPI-WPI mixtures resulted in self-standing gels with better gel performance than LPI, whereas heated LPI-CM mixtures exhibited liquid viscosity. Additionally, MTGase-induced LPI-CM samples showed better gel performance than LPI alone, whereas no self-standing gels formed for MTGase-induced LPI-WPI samples. The power-law model analysis showed that MTGase treated LPI-CM showed lower K ' than heat-treated LPI-WPI with a similar trend observed for n ' values. Overall, under neutral conditions, heating can enhance the gelation performance of LPI-WPI mixtures, while MTGase treatment is beneficial for promoting gelation in LPI-CM mixtures. This study provides valuable insights into effective strategies for substituting dairy proteins with plant proteins to attain the desired gelation performance.

Gelatin-based emulsion gels with transglutaminase (TG) crosslinking exhibit significant potential for delivering fat-soluble bioactive compounds in functional foods. However, the effects of TG-induced structural modifications on the release behavior and stability of encapsulated compounds during storage and digestion have rarely been investigated. In this study, beta-carotene was encapsulated into emulsion-filled gelatin gels to investigate the influence of TG crosslinking time on their structural, mechanical, and functional properties. The result showed that at 4 degrees C, physically crosslinked FG emulsion gels were thermally reversible, exhibiting higher Young's modulus and storage modulus covalently crosslinked TG gels. Large amplitude oscillatory shear analysis revealed that gels formed by gelatin self-assembly were more fragile, more susceptible to nonlinear behavior, and transitioned more quickly to Newtonian fluid dissipation. Increasing the TG crosslinking duration enhanced gel rigidity, particularly at room (25 degrees C) and physiological (37 degrees C) temperatures, by forming a more compact network. However, excessive crosslinking reduced the flexibility and energy dissipation capacity of the gels. Importantly, TG crosslinking significantly improved the storage stability of beta-carotene, enhanced its bioaccessibility, and increased its stability during simulated gastric digestion. The findings of this study offer a promising strategy for structuring gelatin-based emulsion gels with enhanced stability, controlled release, and improved bioactive delivery performance.

In this study, we investigated the effects of whey protein isolate fibril systems (WPF) and soy protein isolate fibril systems (SPF) combined with fish gelatin (FG) on the formation of emulsion gels. The aim was to evaluate how the origin and concentration of these fibril systems influence the structural, interfacial, and rheological properties of FG-stabilized emulsion gels, as well as their impact on creaming stability. FG was mixed with varying concentrations (0-2%) of WPF and SPF at pH 7, forming electrostatic complexes due to the opposite charge interactions between FG and the protein fibril dispersions. The results revealed that adding WPF and SPF increased surface hydrophobicity and enhanced interfacial activity. Increasing WPF concentrations led to a gradual decrease in emulsion droplet size owing to the increased absorbed protein content at the interface. Additionally, there was a significant improvement in the storage modulus of the emulsion gels. Conversely, introducing a small amount (0.1%) of SPF to FG increased the particle size, suggesting potential coalescence, but further increases in SPF concentration considerably reduced the particle size. Furthermore, SPF enhanced the viscoelasticity at lower concentrations, possibly due to a more uniform distribution within the continuous phase. However, excess SPF reduced the storage modulus of the emulsion gels. Our study provides valuable theoretical insights for the application of protein fibril systems in emulsion gel systems.

A causal relationship between food processing and adverse health outcomes is often incorrectly reported. This is evidenced by several processed food classifications which mistakenly claim to categorize foods based on their processing level. Here we used chemical engineering principles to divide food processing to unit operations (physical processing) and unit processes (chemical processing) and established 5 food processing levels (FPL). Unit operations represent the lowest processing levels, FPL 0 and 1. Unit processes may include minor or major (bio)chemical changes resulting in FPL 2 and 3, respectively. FPL 4 is assigned to processing of food formulations with one or more ingredients from FPL 3 and 4. Foods from the different FPL are categorized with guidelines to corresponding processed food intake (PFI) classes, which provides improvements in comparison to the NOVA and other processed food classifications. The PFI classification combines processing and formulation as factors with possible but separate impact on nutritional, health and other outcomes of food intake. The concept of the FPL and PFI classification may be further expanded to indicate the impact of food processing in other applications, such as affordability and sustainability of food products.

The study investigated the interactions between high-methoxyl pectin (HMP) and milk fat globules or membrane (MFGs/MFGM) ingredients. Mixtures of raw milk and HMP at concentration of 0.20 %, 0.30 %, and 0.40 % (w/ w) (designated as 0.20 pectin (Pec), 0.30 Pec, and 0.40 Pec, respectively) underwent cream separation and ultra- centrifugation to enrich the MFGs/MFGM materials, with raw milk without HMP serving as a control. The control and 0.20 Pec exhibited multimodal particle sizes distributions with the additional peaks within the range 0.01-0.10 mu m. HMP at 0.20 % level enhanced system stability of MFGs/MFGM, indicated by a higher zeta-potential and a lower instability index compared to 0.30 % and 0.40 % levels. Fourier transform infrared spectroscopy (FTIR) showed HMP increased the random coil (%), accompanied by a reduction of alpha-helix structure (%) in MFGs/MFGM ingredients. SDS-PAGE analysis reveal lower band intensities of MFGM proteins, such as periodic acid Shciff III (PAS III), cluster of differentiation 36 (CD36), and butyrophilin (BTN) in the upper layers of 0.40 Pec compared to 0.30 Pec and 0.20 Pec materials. Rheograms demonstrated decreased viscosity in all materials with HMP, indicating shear-thinning behavior confirmed by flow behavior indexes (n) (0 < n < 1) using the Herschel-Bulkley model. Hierarchical cluster analysis (HCA) of the structural, compositional, physical stability, and rheological properties of MFGs/MFGM materials demonstrated that the 0.30 % and 0.40 % HMP levels gave the most pronounced effect.

Whey protein fibrils (WPF) have attracted increasing attention due to their superior functionality in various applications, including emulsification. However, achieving stable nanoemulsions across different pH conditions remains a challenge. This study aimed to explore the emulsifying properties of WPF combined with cold-water fish gelatin (CFG) across different pH levels and compare them to whey protein isolates (WPI) as emulsifiers for oil-in-water nanoemulsions. Creaming stability results showed that CFG-WPI/WPF emulsions were stable at pH 3, 9, and 11, producing nanosized droplets. However, at pH 5 and 7, emulsions exhibited aggregation and larger droplet sizes, indicating instability. To enhance stability at neutral pH, various protein ratios and higher concentrations were tested. Increasing the protein concentration improved CFG-WPI stability, but CFG-WPF emulsions showed rapid creaming and bimodal droplet distributions. Adjusting the ratio of CFG to whey proteins revealed that CFG-WPI emulsions were most stable at 4:1 and 1:1 ratios, while CFG-WPF emulsions showed pronounced aggregation at 1:1 ratio. Increasing the CFG to WPF ratio improved stability. The findings in this study could offer valuable insights for developing stable protein-based nanoemulsion systems for food and pharmaceutical applications.

Food processing and processed food with chemical engineering definitions for unit operations (UO) and unit processes (UP) were reviewed to establish five Food Processing Levels (FPL 0 to 4) with corresponding Processed Food Intake (PFI 0 to 4) categories. The FPL 0 to 4 scaling relates to physical changes and (bio)chemical transformations during processing, i.e., UO result in physical changes and losses of cellular structures with an FPL of 0 to 1 whereas UP involve (bio)chemical modifications and result in FPL 2 to 4. The FPL has uses in a variety of engineering and other applications, e.g., sustainability of food processing. Each FPL is differently responsible for food properties, including texture and sensory characteristics and food matrix effects in digestion with an impact on energy intake, nutritional properties and health. The PFI 4 represents formulated foods as Processed Ingredients Foods, including intermittent processing. The PFI categories allow comparison of FPL and food intake data from various PFI groups for different research, advisory, public health, general and other applications. The PFI classification is simple, and it can be used beyond Nova to relate FPL and food formulation to processed food intake and thereby to food processing impact on diet and health.

Despite water molecules are strongly hydrogen bonding to hydrophilic solids, the Brunauer-Emmet-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) surface adsorption models have been widely accepted to describe water sorption properties of biological and food materials. These mathematically quite similar models use parameters which include a theoretical ‘monolayer’ value and one or two other parameters which describe ‘surface affinity’ in thermodynamic terms as heat of sorption. A high surface affinity indicates a strong surface binding of water molecules and preferential monolayer adsorption prior to multilayer sorption. Conversely, biological materials are water plasticized and suffer physicochemical changes at various stages of water sorption. Dynamic water sorption measurements often show regions where time-dependent changes in material characteristics, such as viscous flow and crystallization, may occur as a result of the glass transition. The two or three parameters of the BET and GAB models, respectively, are useful in the analysis of water sorption characteristics of individual substances, although the existence of a monolayer particularly in multicomponent materials may not be justified. Fitting the models to experimental data may occur rather for empirical than theoretical reasons.

The electrostatic interactions and complex formation of Tremella fuciformis polysaccharide (TPS) with whey protein (WPI), lentil protein (LPI), and soy protein (SPI) isolates were studied. The molecular size and components in each protein isolate complexed with TPS were characterized, along with the structural changes in the protein components, induced by TPS complexation. The stability of emulsions prepared with protein:TPS complexes was also evaluated (pH 4.5). Compared to WPI, the LPI and SPI protein components exhibited more negative charges and larger molecular sizes. Independent of the isolate type, pH(c) of all protein:TPS systems remained unchanged and pH(phi 1) shifted to higher pHs as the protein/TPS ratio increased; the pH(opt) of WPI:TPS and SPI:TPS occurred at higher values as the protein/TPS ratio increased, while the pH(opt) of LPI:TPS system was less dependent on the biopolymer mixing ratio, probably due to the lower solubility of LPI. Protein components such as beta-LG in WPI, convicilin, vicilin, and basic legumin in LPI, and alpha' subunits of 7S beta-conglycinin and acidic subunits of 11S glycinin in SPI might be the main components interacting with TPS for complex formation. Different proteins exhibited distinct trends in changing their secondary structural elements when interacting with TPS. At pH 4.5, a high proportion of TPS increased the stability of protein emulsion, regardless of the protein used. The WPI:TPS emulsions with low content of TPS were highly destabilized due to the formation of insoluble WPI:TPS complex coacervates, a phenomenon not observed in emulsions stabilized by the LPI:TPS or SPI:TPS systems.

The healthy benefits of milk fat globules and membrane (MFGs/MFGM) ingredients are increasingly recognized in the dairy industry. In this research, we examined the effects of ultrasonic treatment on the physicochemical and rheological properties, as well as the emulsions stability of MFGs/MFGM derived from bovine raw milk. Fresh milk was subjected to sonication at frequencies of 20 kHz and 40 kHz, either individually or simultaneously, for durations of 5 min or 15 min, using work/rest cycles of 5 s on and 3 s off. Bovine milk, without any treatment, served as the control. Regardless of the intensity difference, ultrasonic treatment for 5 min resulted in more pronounced changes in the regions of Amide II (1600-1500 cm- 1), Amide III (1500-1200 cm- 1), and fingerprint region (1200-1900 cm- 1) compared to both the 15 min treatments and control MFGs/MFGM. Principal component analysis (PCA) conducted on the entire spectra, as well as in the regions of Amide I, Amide II, and the fingerprint spectra, clustered the 5 min treatment distinctly from the control and MFGs/MFGM ultrasonically treated for 15 min. MFGs/MFGM samples following 20 kHz and 40 kHz synchronous treatment for 15 min exhibited lower absorbance bands at 1727-1726 cm- 1, whereas a higher content at 1740 cm-1 was observed compared to control MFGs/MFGM. Additionally, a more significant reduction in the intramolecular beta-sheet content in 20 + 40 kHz/ 15 min treatment was observed. According to the sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) patterns, a diminished intensity of Periodic Acid Schiff 6/7 (PAS 6/7) bands was observed across all the MFGs/MFGM. Ultrasonic treatment retained more caseins while reducing the beta -LG levels compared to the controls, enhancing the stability of MFGs/MFGM, except in MFGs/ MFGM subjected to 20 and 40 kHz simultaneously treated for 15 min. The irregular sphericity of fat globules was noted particularly in MFGs/MFGM treated at 20 kHz independently or in combination with 40 kHz for 15 min. According to the confocal laser scanning microscopy (CLSM), ultrasonic treatment facilitated the binding of caseins or whey proteins to the MFGs surface and induced flocculation of membrane proteins. Hierarchical cluster analysis (HCA) heat map further underscored the impact of ultrasonic treatments on the structural and compositional changes, as well as rheology and emulsions stability, of MFGs/MFGM.

Background: Dairy powders enriched with milk fat globules (MFGs) and milk fat globule membrane (MFGM) materials are gaining interest in food industry due to their bioactive benefits, including the promotion of brain development and cognitive functions, as well as improvements in gut health and immunity. MFGs/MFGM ingredients have been incorporated into infant formula (IF) to bridge the nutritional gap between formula and breast milk. The structure and composition of MFGs/MFGM ingredients significantly influence their functionalities and physiological properties. Scope and approach: This review provides an update on recent research concerning the factors influencing the structure, composition, and functionalities of MFGs/MFGM ingredients, including the species, lactation stage and feeding methods. Additionally, conventional separation methods are discussed versus novel membrane filtration techniques. The main part of this review covers the recent progress and trends arising from the influence of the industrial dairy produce units, including thermal treatment and low temperature storage, homogenization, and non-thermal processes. Key findings and conclusions: Variability in reports on the structure and composition of MFGs/MFGM across studies poses challenges in discerning whether these differences arise from varied processing techniques or analytical methods. Establishing standard analytical methods remains an ongoing research topic. By-products such as cheese whey or buttermilk continue to serve as primary raw materials for the preparation of MFGs/ MFGM ingredients in the industry. Studies on the preparation of MFGs/MFGM materials while maintaining their natural state are relatively limited. Further research into the structural and compositional changes of MFGs/ MFGM during food processes is essential, as it has the potential to provide the key information on their physiological properties and tech-functionalities.

Background: As concern regarding human health, environmental increases, and the need for sustainable food supplies rises, plant proteins are gaining increasingly popularity as alternatives to dairy proteins. The substantial disparity in structural properties and gelation mechanisms between plant proteins and dairy proteins, along with a lack of comprehensive and systematic understanding of their underlying mechanisms under various modification strategies, pose challenges in unlocking the potential substitution of dairy proteins with different plant proteins. Scope and approach: The review offers insights into the structure, gelation mechanisms of heat and cold-induced gels of dairy proteins and plant proteins. Furthermore, diverse modification techniques for tailoring the structure of these proteins have been discussed, including chemical, physical, and biological modifications, as well as modifying mechanisms and their advantages and disadvantages. Key findings and conclusions: As with whey globular proteins, plant globular proteins usually have compact globular structures and are more prone to heat, making the denaturation of their globular proteins a prerequisite step for gelation. Contrary to globular proteins, casein micelles exhibit flexible random coil structures and good conformational stability to heat in neutral or higher pH but lose stability in acidic conditions. Different modification strategies exhibit diverse mechanisms and peculiarities. Complex coacervation is highly system dependent, while the enzymatic hydrolysis should be controlled in limited degree. Transglutaminase treated gels behave differently when the amount and accessibility of target lysine and glutamine residues differs. Moreover, exploring effective modification strategies for binary plant and dairy proteins to improve their gelation performance can be done in the future.

Concerns about health, the environment, and sustainable food supply have inspired researchers into searching new alternative plant proteins to dairy proteins. This study investigated thermal treatment coupled with pH manipulation (3.0, 5.0, 7.0, and 9.0) on the structural and gelation performance of pea, chickpea protein, and casein. Gel electrophoresis suggested that only specific fractions contributed to disulfide bond-mediated aggregates formation: bovine κ-casein and αs2-casein in casein micelles, acidic and basic legumin subunits in pea and chickpea protein. No protein formed self-standing gels but precipitated in macroscopic flocs at pH 5.0. Casein displayed optimum gel performance at pH 3.0 (storage modulus (G′) of 2596.00 Pa, hardness of 603.47 g, water holding capacity of 94.92%), and transitioned into fluid-like viscous state (G′ < 1, loss tangent >1) under neutral or higher pH conditions. Pea protein did not form self-holding gels but aggregates with globular particles over all test pH. Nevertheless, chickpea protein formed self-standing gels regardless of pH (except 5.0) and peaked gel performance at pH 9.0. Hence, this study indicated considerable potential of casein in acidic thermal gel-based food products and confirmed the promising applications of chickpea protein as an alternative to pea protein across diverse pH conditions, and to casein in neutral and alkaline food gel formulations. In addition to providing scientific insight understanding the effects of thermal treatment coupled with pH manipulation on the performance of plant-based protein and dairy protein, this research sheds light on the promising prospects of incorporating chickpea protein into gel-based food formulations.

A growing global concern about human health, environment, and sustainable food supplies has motivated researchers to find new alternatives to dairy proteins. To investigate the effects of pH and protein varieties on the thermal gelation behaviors, plant protein (soy and lentil) and dairy protein (whey) were subjected to a variety of pH treatments. SDS-PAGE showed that only partial subunits of soy and lentil protein were involved in disulphide bonded aggregate formation regardless of pH, and that of whey protein was inhibited at acidic conditions and facilitated at higher pH. Both soy and lentil protein did not form self-standing gels at pH 5.0, while whey protein did, and all proteins displayed different morphologies as pH moved away from 5.0, from white, opaque, and heterogeneous to relatively transparent and homogeneous. Soy protein exhibited its optimal gel performance at pH 9.0 (storage modulus of 946.05 Pa) with the highest content of alpha-helix, intramolecular beta-sheet, and intermolecular/aggregated beta-sheet, while whey protein demonstrated its peak gel performance at pH 7.0 (storage modulus of 26271.90 Pa). Lentil protein displayed the best gel performance at pH 3.0 and was comparable to that of whey protein (storage modulus of 5366.00 and 4965.00 Pa, respectively). These findings confirmed that lentil protein has the potential to substitute whey and soy protein in formulations of diversified food products in some specific pH systems. This work highlighted the importance of pH control to achieve desired gelation performance and offered valuable insights for selecting suitable protein alternatives in formulating plant-based food products.

Proteins' physicochemical and structural properties critically affect their interactions with polysaccharides. The effect of ultrasound treatment (0-40 min) on the physicochemical properties of soluble lentil proteins (LPs) was investigated. The interaction between LPs (ultrasound-treated for different times, U0-LP, U5-LP, and U40-LP) and Tremella fuciformis polysaccharides (TPS) under different pHs, biopolymer mixing ratios, and total biopolymer concentrations was studied. With the sonication duration increasing, decreased intrinsic fluorescence, higher zeta potential values, and increased hydrophilicity were observed for the sonicated LP samples. The molecule weight of LPs remained unchanged, and their secondary structure changes were independent of the sonication duration. The soluble LPs:TPS complexes and insoluble complex coacervates formed at pH 6.5 (pH(c)) and pH 6.0 (pH(phi 1)), respectively, regardless of the mixing ratio and the LP type. The maximum formation of insoluble LPs:TPS complex coacervates (pH(opt)) occurred at the biopolymer mixing ratio of 4:1 at pH 3.0, 2:1 at pH 3.0, and 2:1 at pH 3.5 for the U0-LP:TPS, U5-LP:TPS, and U40-LP:TPS systems, respectively. The pH(phi 1) and pH(opt) of all the three LPs:TPS systems shifted to higher pH values as the total biopolymer concentration increased. With the greatest dynamic quenching constants (K-sv) and binding site (n) values, U40-LP exhibited the strongest binding affinity with TPS. This was consistent with the highest viscosity of their mixture solution under pHs greater than pH(opt). The overall results suggest that ultrasound-treated proteins showed a stronger electrostatic interaction with TPS compared to untreated proteins.

Milk fat globules or milk fat globule membranes (MFGs/MFGM) have been added to the infant formula to fortify the phospholipids and narrow the nutritional gap from breast milk. The main aim of this study was to profile the interfacial and thermal properties of MFGs/MFGM prepared from ultrasonicated bovine milk. Bovine milk was sonicated at ultrasonic intensities of 20 kHz and 40 kHz independently or synchronously with the duration time of 0 min (control), 5 min, 10 min, and 15 min (work/rest cycles = 5 s: 3 s). Ultrasonic treatments at 20 kHz/ 5 min and 20 + 40 kHz/ 5 min improved the volume density (%) of smaller particles (1-10 mu m) while significantly decreasing the surface hydrophobicity (H-0) (p < 0.05). 40 kHz/5 min samples showed significantly higher zeta- potential than the other samples (p < 0.05), which might be because more negative charges were detected. In comparison with control samples, ultrasonic treatments decreased the interfacial tension (pi) between the air and MFGs/MFGM liquid phase. 20 kHz ultra-sonicated treatments decreased the diffusion rate (k (diff)) of MFGs/MFGM interfacial compositions significantly as the duration prolonged from 5 min to 15 min (p < 0.05) but did not affect the adsorption or penetration rate (k (a)) (p > 0.05). X-ray diffraction (XRD) results showed that alpha-crystal peaks only existed in control and ultrasonicated 5 min samples but disappeared in all 15 min samples. According to the different scanning calorimetry (DSC), one or two new exothermic events (in the range of 17.29 - 18.81 degree celsius and 22.14 - 25.21 degree celsius) appeared after ultrasonic treatments, which, however, were not found in control samples. Ultrasonic treatments resulted in the low-melting fractions (LMF) (T-M1) peaks undetectable in MFGs/MFGM samples in which only peaks of medium-melting fractions (MMF) (T-M2) and high-melting fractions (HMF) (T-M3) were detected. Compared with the control, both enthalpies of crystallisation (Delta H-C) and melting (Delta H-M) decreased in ultrasonicated samples. In conclusion, ultrasonic treatment affects the interfacial and thermal properties of MFGs/MFGM.

This study aimed to explore the impact of ultrasound treatment (UT) on the interactions between whey protein isolate (WPI) and Tremella fuciformis polysaccharide (TPS) in aqueous dispersions at different pHs (3.0, 4.5, and 6.5); i.e., the physicochemical properties of WPI-TPS composite systems were studied in comparison to homogeneous WPI or TPS aqueous dispersions. Relative to 40 kHz and 20/40 kHz, 20 kHz was shown as the most effective ultrasound frequency in changing the tertiary structure of WPI. The electrostatic interaction between WPI and TPS at pH 4.5 and 6.5 could be improved by appropriate UT (20 min), as evidenced by higher turbidity values (0.80 f 0.01 and 0.13 f 0.01, respectively) and decreased absolute zeta-potential values (-18.20 f 0.88 mV and -31.77 f 1.05 mV, respectively). With longer UT, aggregation events were evidenced in the WPI-TPS system at pH 4.5, where the particle size of the structure initially decreased from 4.28 f 0.14 mu m to 2.54 f 0.06 mu m (20 min sonication) and increased thereafter to 21.5 f 1.64 mu m (80 min sonication). Increases in n-sheet and random coil were observed for both homogeneous WPIs and WPI-TPS systems sonicated for 20 min. Under UT, the WPI-TPS systems exhibited different changing trends in surface hydrophobicity (H0) and emulsification properties. The H0 of the WPI-TPS system at pH 4.5 increased significantly with the duration of UT (0-80 min); moreover, this system showed enhanced values for emulsifying activity index and emulsifying stability index following UT (especially after 20 min treatment).