This study aims to interlink the colloidal properties of lentil protein emulsions formulated with protein suspensions pre-treated with high pressure homogenization (HPH), thermal treatments (TT) and its combination (HPH + TT). Lentil protein suspensions were pre-treated with HPH (50 MPa), thermal treatment (120 °C for 60 s) or HPH followed by the TT. The physicochemical properties of these pretreated suspensions, as well as of emulsions prepared from them, were compared with those of an untreated sample. The particle size distribution of the suspensions was significantly reduced by HPH, with the volume-weighted mean diameter (D [4, 3]) decreasing from 3.63 μm (untreated) to 1.48 μm (HPH). TT and HPH + TT suspensions had a similar particle size distribution to the untreated sample, indicating a partial protein aggregation. The samples showed a transition from shear-thinning to near Newtonian behaviour when treated with TT and HPH + TT, which also enhanced their physical stability. The emulsion formulated with the pre-treated suspensions had a significantly lower particle size distribution compared to the untreated samples. Interestingly, the HPH + TT emulsion had the lowest particle size with a D [4, 3] of 1.07 μm and displayed the highest physical stability compared to the sample. The improved emulsion stability is likely due to enhanced enhanced physical properties in the protein suspensions, which increased their functionality and interfacial activity, leading to more effective stabilization of the oil droplets. These findings demonstrate that the combining HPH and thermal treatment can significantly improve the stability and functionality of high-solids lentil protein-stabilised emulsions, supporting their use in sustainable young child infant formula.

This study was designed to investigate the effects of heat treatment and selective thiol blocking using N-ethylmaleimide (NEM) on protein partitioning during microfiltration (MF) of whey. Clarified sweet whey was subjected to five treatments: untreated control (CTRL), pH-adjusted (CTRLpH), pH + NEM (T-NEM), pH + heat (T-Heat), and pH + NEM + heat (TNEM + Heat). Significant differences (P < 0.05) were observed in protein permeation and retention. Compared to CTRL, protein content in the permeate was 22 % and 16 % lower in T-Heat and TNEM + Heat, respectively. Conversely, protein retention in the retentate was 22 % and 16 % higher in the same treatments. These results confirm that disulphide bond-mediated aggregation reduces protein permeation during MF. The findings provide new insight into how thiol reactivity and thermal treatment influence protein transmission. This scientific insight supports the development of targeted strategies (e.g., reduced- or non-thermal processing) to increase protein yield and enhance processing sustainability in the production of value-added whey streams and whey protein ingredients.

The implications of multispecies sward (MSS) grazing on sensory and quality characteristics of dairy products are inadequately understood. This study compared Cheddar cheese derived from MSS and perennial ryegrass (PRG) grazing, analysing for differences in ripening characteristics and sensory attributes. In this spring-calving production system, seasonality was considered by completing investigations at mid- and late-lactation. No meaningful differences in ripening attributes, free fatty acid profile, and nearly all volatile compounds, were associated with pasture type. Significantly higher toluene abundance was associated with MSS-derived cheese, which might provide an opportunity as an authentication biomarker. Pasture type was associated with some significant fatty acid profile differences, but greater differences resulted from seasonality. Consumer assessors found no significant differences between MSS and PRG-derived cheese, while semi-trained panellists found significant differences in some sensory attributes. Within this study, MSS- and PRG-derived Cheddar appear to be practically equivalent, providing assurance that this more sustainable pasture type might be adopted without adverse impacts to this high-value commodity.

The rennet and acid coagulation properties of reconstituted micellar casein concentrate prepared using cold or warm microfiltration (MF), at similar casein contents, were investigated, with low-heat skim milk powder (LHSMP) as a control. The MF retentates had higher casein content (as % of total protein) compared with LHSMP, and heat-induced whey protein-casein aggregates were only present in LHSMP. All MF retentates showed shorter rennet coagulation times and higher gel strengths than LHSMP, which may be linked to lower levels of whey protein (either native or denatured). At similar casein contents, longer rennet coagulation times were evident for cold MF retentates compared with warm MF retentates, as the ratio of κ-CN as a function of total increased with the depletion of β-CN. In terms of acid-induced coagulation, all MF retentates coagulated at a pH >5, higher than the gelation pH of LHSMP (4.7-4.9), which was confirmed by microscopic and textural analysis. An inflection point (increase, followed by a decrease) in the storage modulus value was seen during the acidification of warm MF retentates, but not cold MF retentates; this may be related to structural rearrangements of the gel initiated by release of colloidal calcium phosphate and compacting of the structure of warm MF retentate gels as pH decreased. Both warm and cold MF retentates exhibited shorter rennet coagulation times, stronger rennet-induced gels and higher acid-induced gelation pH compared with LHSMP, which might influence their use for the manufacture of cheese or yogurt with tailored functionalities.

This study investigated the impact of high pressure homogenization (HPH) on the nonlinear rheological behaviour of pea, whey and pea:whey hybrid emulgels. Pea protein suspensions (5.5% protein) were pre-treated with HPH (6-600 MPa), prior to mixing with untreated whey proteins to form hybrid suspensions. Whey protein suspensions showed the smallest particle size (0.5 mu m) and high solubility (94%). In pea protein suspensions, HPH progressively reduced particle size and increased solubility, reaching 7.9 mu m and 94.4% at 100 MPa, respectively, whereas it promoted the formation of larger aggregates in hybrid suspensions, leading to larger particle size (80.1 mu m at 100 MPa) and a consistent solubility (57.6 +/- 1.6%). Rheological measurements demonstrated that whey proteins formed the strongest emulgels, while pea emulgels exhibited the highest storage modulus (G '), at 15 MPa. In contrast, hybrid emulgels exhibited greater gel strength at 100 MPa, with G ' (1 Hz) increasing from 5.5 kPa in the untreated sample to 14 kPa. Lissajous-Bowditch figures revealed that hybrid emulgels showed more gradual transitions from solid-to liquid-like behaviour with increasing strain amplitude, compared to untreated samples. The quantification of nonlinear responses using the Chebyshev decomposition method confirmed strain stiffening and shear thinning across all emulgels. Notably, hybrid emulgels showed accelerated increases in stiffening and thickening indices, indicating stronger gels at 100 MPa. This study demonstrated that HPH enables the formulation of hybrid emulgels with improved rheological functionality, providing new fundamental contributions in the understanding, development, and application of such a useful technology to hybrid protein systems.

Background The growing demand for health-conscious diets has increased interest in combining dairy and plant proteins, referred to as dairy-plant hybrid food systems. These hybrid systems offer significant potential for improving calcium intake, which is often inadequate from plant-based diets. However, the bioaccessibility and bioavailability of calcium in such complex matrices remain a critical challenge due to interactions between proteins, minerals, and other food components. Despite growing interest in hybrid foods, studies addressing calcium bioaccessibility in these systems remain limited. Scope and approach This review offers a comprehensive analysis of calcium bioaccessibility and bioavailability in dairy-plant hybrid systems, with an emphasis on factors influencing calcium bioaccessibility and bioavailability, as well as formulation, physical and biological processing strategies that can enhance calcium bioavailability of these systems. Furthermore, current challenges and future perspectives in hybrid product development, including nutritional advancement with respect to calcium, are discussed. Key findings and conclusions The bioaccessibility and bioavailability of calcium in plant proteins are limited by several factors (e.g., molecular interactions, processing technologies, chemical form of calcium, and delivery matrices). Special attention has been directed toward formulation approaches (e.g., calcium fortification, micronization, solid dispersion emulsification, and incorporation of hydrolyzed proteins/peptides), physical (e.g., milling, cooking, extrusion, direct steam injection, pulsed electric fields, high-pressure homogenization), and biological approaches (e.g., germination, fermentation, and enzyme treatment) with a focus on enhancing calcium bioaccessibility and bioavailability. Addressing key challenges (e.g., casein network formation, poor structural and physicochemical stability) is required for advancing dairy-plant hybrid systems with enhanced calcium bioaccessibility and bioavailability.

Background Cows can typically utilise only 10-30% of dietary nitrogen, with the rest excreted in urine and faeces, contributing to nitrate leaching and ammonia volatilisation. There is increasing desire to incorporate multispecies sward pastures into dairy systems to improve diversity and sustainability of primary production and to improve N use efficiency. Aim The objective of this study was to explore the effects of including white clover (WC) and plantain grass species with perennial ryegrass (PRG) pasture systems on milk composition and quality. Methods Nine rumen-cannulated cows were randomly allocated to one of three dietary treatments in a Latin square design. The dietary treatments consisted of PRG only receiving 50 kg of inorganic N/ha (GO), a combination of PRG and WC receiving 25 kg of inorganic N/ha (GC), and a combination of GC and plantain receiving 25 kg of inorganic N/ha (GCP). Milk samples were collected and analysed for milk composition, milk metabolomics, fatty acids and techno-functional properties, including rennet gelation and heat stability. Major Findings The inclusion of plantain or WC grass species had a significant effect on milk composition, particularly for nonprotein nitrogen (NPN) and fat content, both of which were present in higher concentration in milk of cows fed GO compared with GCP. Of the 42 metabolites and 22 FA identified, three metabolites and seven FA were significantly influenced by dietary treatments according to the mixed effect model. Furthermore, receiver operating characteristics analysis highlighted three metabolites and eight FA as potential biomarkers to distinguish between dietary treatments [area under curve (AUC) value >0.7]. Dietary treatment did not have a significant effect on the functional properties of milk. Scientific and Industrial Implications The inclusion of these pastures did not appear to have any negative effects on milk composition or functionality, offering confidence for their further adoption in the future.

This study aims to characterise the milk metabolome from a seasonal pasture-based dairy system using 1H-NMR spectroscopy. Over 41 weeks, ten dairy farms were visited weekly for the collection of raw bulk tank milk samples (n = 410) and three commercial pasteurised skimmed milks were also purchased weekly (n = 123). In total, 38 milk metabolites were quantified, 30 of which exhibited significant seasonal variation. Multivariate analysis identified several key compounds associated with seasonal metabolic changes. Winter-Feb milk, corresponding to early-lactation period, was enriched in ketone bodies, O-phosphocholine, creatinine, and glucose-1-phosphate, reflecting increased metabolic stress and negative energy balance following parturition. In contrast, autumn milk, corresponding to late-lactation, contained higher concentrations of choline and urea, indicative of improved energy status but reduced nitrogen use efficiency. These findings highlight the potential of milk metabolomics as a valuable tool for monitoring physiological status and guiding interventions to enhance sustainability in dairy systems.

Meeting the world’s growing population’s protein demand, while minimising the environmental impact of food production, is one of the greatest challenges of our time. Livestock production systems are facing challenges regarding their environmental impact, while cropping systems are seen as more environmentally friendly protein sources. This dichotomy is observed in environmental policies. While the contribution of protein production to climate change must be reduced, the nutritional impact for a growing world population and the economic impact for farmers must be considered in policy developments. Protein security is defined as the number of individuals having their protein requirements met daily. This paper evaluates the net contribution, i.e., considering human edible inputs and outputs involved in the production process, of animal- and plant-based products, to protein output and security for the Republic of Ireland. The effects of environmental policies on this contribution are also analysed. Milk and arable production contribute more to net protein security than beef or sheep meat production. Overall, the Irish protein sector can meet the protein requirements of ca. 20 million people annually, 35 million people if digestibility is considered. While both Scenarios investigated would lead to a reduction in GHG emissions, a Business-as-Usual Scenario would lead to a decrease in gross margin but to an increase in protein output and security. A Climate Policy Scenario would lead to an increase in net protein output, but net digestible protein output would decrease due to beef protein being substituted for plant-based protein sources with a lower digestibility.

Understanding whey protein concentrate (WPC80) powder rehydration over time is important for those who incorporate powders into food products. Inhibited rehydration behavior and prolonged rehydration time can cause processing challenges and increased production costs. In this study, we investigated how spray-drying inlet, outlet, and storage temperatures influenced the rehydration behavior of WPC80 powders, elucidating the relationships between particle morphology, powder bulk density, protein modifications, and inhibited rehydration. Powder rehydration over time was measured using the novel broadband acoustic dissolution spectroscopy method. This method monitors gas release during rehydration, which occurs simultaneously with water penetration. Powder dried at higher temperatures released more gas and had a prolonged delay before complete dissolution (>990 s) compared with those dried at lower temperatures (730 s). These observed differences can be attributed to contributions from various factors, including alterations in particle size and shape, powder packing behavior, and protein modifications, such as protein denaturation and lactosylation. Our findings suggest that higher spray-drying inlet and outlet temperatures, as well as storage at 40°C for 2 mo may deteriorate rehydration properties.

Non-protein nitrogen (NPN) is a fraction in milk comprised of numerous nitrogenous non-proteinaceous components, including but not limited to urea, ammonia, free amino acids, milk-derived peptides, and polyamines. Existing literature indicates significant differences in NPN concentrations and components between human and bovine milk. This also translates to differences in NPN concentrations or profiles in infant formulas manufactured from bovine milk ingredients. Many of the existing data are in some instances, decades old and may not accurately represent the concentrations of NPN in current formulas due to differences in raw materials and advances in analytical methods and processing techniques. Additional investigations are required to better reflect the current concentrations of NPN and the materials that contribute to NPN in infant formulas. In recent years, there has also been an increase in the interest in the functional roles and health benefits associated with many of these NPN components. This structured narrative review synthesises current knowledge on NPN in the context of infant nutrition; the NPN components, their biological functions, analytical methods of detection, key areas of consideration for the topic of NPN and future perspectives for the utilization of NPN in infant formula. The review was conducted using a targeted literature search and thematic synthesis approach. Advancing the understanding on the NPN fraction in milk will enable the development of next-generation infant formulas to more closely mimic the nutritional profile of human breast milk.

Model infant formula protein systems (MIFPSs) composed of dairy ingredients selected to have low innate urea contributions were formulated to simulate a stage 1 (0-6 months) infant formula. The impact of urea concentration on the techno-functional properties of the MIFPSs was investigated through the addition of urea at low (0.9 mM), medium (1.7 mM) and high (3.7 mM) concentrations, designed to span the concentrations of urea reportedly found in human milk and infant formula (2-6 mM). For further insights, the effects of urea at a higher concentration (similar to 12 mM) were also investigated. All data were compared with a control system, containing no added urea. Techno-functional analyses included dynamic foam analysis, heat stability, viscosity during thermal processing, buffering capacity, zeta potential and solubility of each of the systems across a pH range of 6.4-7.4, with protein profiling of the thermally processed samples also conducted. Increased concentrations of urea increased the foamability, heat stability and buffering capacity. In contrast, solubility indices remained low across all systems (sediment volumes typically <= 0.20 mL across pH 6.4-7.4), indicating minimal impact of urea on protein solubility. Similarly, zeta potential values showed only minor variation between treatments, remaining within a narrow range of approximately -14 to-18 mV across all pH conditions. SDS-PAGE analysis confirmed no evidence of irreversible protein aggregation following thermal processing. The findings of this study have advanced the understanding of the role that urea plays in these techno-functions, so if removed or altered, the implications for physical stability and functionality of such products can be predicted.

Polyamines (PAs), specifically putrescine (PUT), spermidine (SPD) and spermine (SPM), are bioactive compounds which are important in various physiological processes, supporting the growth and development of infants. Previous studies have demonstrated significant differences in the PA content and profiles between human milk and infant formulas. The objective of this study was to enhance understanding of the PA content and profiles in human milk, as well as in dairy ingredients commonly utilized in the production of infant formula. PA precursors, individual PAs and their acetylated derivatives were analysed in human milk collected from a cohort of US mothers. SPD was determined as the most abundant PA in this human milk cohort, followed by SPM and PUT. A comprehensive analysis of the individual PA contents was also conducted in multiple dairy ingredients which were categorised based on their protein content (low: similar to 0-13 %, medium: 25-35 %, and high: 70-90 %). Notably, PUT was the most abundant PA in the medium and low protein content dairy ingredients, while SPM was predominant in the high protein content ingredients. The insights gained from this study will not only inform the development of next-generation infant nutritional formulations but will also guide future research on the nutritional adequacy of infant formulas.

Polyamines are a group of organic compounds that can be found in a variety of foods such as meat, fish, vegetables, and milk products including infant formula. Existing methods developed for the quantification of polyamines in infant formulas do not assess the matrix effect and therefore are potentially under- or over- quantifying the polyamine content. Infant formula is a specialized food group where accurate quantification of polyamines is desired. In the current study, a detailed analytical method for the quantification of polyamines in an infant formula matrix was developed using reverse-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV). The matrix effect was also evaluated during method development. The new method was validated in terms of trueness, precision, linearity, LOD/LOQ and uncertainty. LODs ranged from 80 to 200 ppb and LOQs ranged from 240 to 600 ppb. Correlation coefficients ranged from R2= 0.99-1.0. A fit for purpose, widely accessible analytical method for the absolute quantification of polyamines in an infant formula matrix now exists.

The increasing demand for plant-based foods has led to significant growth in the availability, at a retail level, of plant-based cheese analogue products. This study presents the first comprehensive benchmarking of commercially available plant-based cheese analogue (PBCA) products in the Irish market, comparing them against conventional cheddar and processed dairy cheeses. A total of 16 cheese products were selected from Irish retail outlets, comprising five block-style plant-based analogues, seven slice-style analogues, two cheddar samples, and two processed cheese samples. Results showed that plant-based cheese analogues had significantly lower protein content (0.1–1.7 g/100 g) than cheddar (25 g/100 g) and processed cheese (12.9–18.2 g/100 g) and lacked a continuous protein matrix, being instead stabilized largely by solid fats, starch, and hydrocolloids. While cheddar showed the highest hardness, some plant-based cheeses achieved comparable hardness using texturizing agents but still demonstrated lower tan δmax values, indicating inferior melting behaviour. Thermograms of differential scanning calorimetry presented a consistent single peak at ~20 °C across most vegan-based variants, unlike the dual-phase melting transitions observed in dairy cheeses. Sensory analysis further highlighted strong negative associations between PBCAs and consumer-relevant attributes such as flavour, texture, and overall acceptability. By integrating structural, functional, and sensory findings, this study identifies key formulation and performance deficits across cheese formats and provides direction for targeted improvements in next-generation PBCA product development.