Many seaweeds can be considered as nutritious supplements and have a high protein content, are low in fat, and contain several vitamins, minerals, and bioactive compounds. Yogurt, a popular fermented dairy-based food, is widely regarded as healthy. Thus, supplementing yogurt with some particular seaweeds is a promising approach to develop a healthy product. The impact of adding selected types of seaweeds (Alaria esculenta and Saccharina latissima) to yogurt on its nutritional, physicochemical, and microbiological properties during storage, was evaluated. Two yogurt formulations were prepared, supplemented with either 0.25

This study investigates interactions between whey proteins and procyanidins (PAC) using a multifactorial, multivariate analytical approach. A Box-Behnken experimental design (BBD) was employed to systematically evaluate the effects of three physicochemical factors, pH, ionic strength, and high-pressure homogenization (HPH), on the formation of WPI-PAC complexes. Multivariate analysis, including principal component analysis (PCA), was used to enhance the detection and interpretation of spectral variations associated with chemical groups and structures involved in complexation. While zeta potential measurements showed negligible differences between WPI-only and WPI-PAC mixtures, dynamic light scattering revealed an increase in particle size, suggesting altered aggregation behavior. Fourier-transform infrared (FTIR) spectroscopy identified key spectral vibrational modes modified by the WPI-PAC interaction, particularly in the amide II region (1540 cm-1), associated with hydrogen bonding, and the amide I region (1630 cm-1), indicative of β-sheet-related hydrophobic π-π stacking. Proton nuclear magnetic resonance (1H NMR) demonstrated reduced signal intensity of certain resonances in the aromatic/amide region under optimal binding conditions, suggesting interaction between protein and PAC. Maximal complexation occurred at the center point of the BBD, demonstrating a simple and cost-effective strategy for probing the environmental factors affecting protein-polyphenol interactions relevant to food systems.

The techno-functional properties of plant-based protein ingredients are critical for developing food formulations and greatly depend on the production method. The physicochemical and techno-functional properties, as well as the in vitro digestibility, of mung bean protein isolates (MBPIs) produced by isoelectric precipitation (IEP) and ultrafiltration-diafiltration (UFDF) were compared. Both MBPIs had comparable protein contents (∼84%) but the protein structure was slightly affected by isolation method, as MBPI-IEP exhibited lower surface hydrophobicity and slightly higher denaturation temperature. These differences were likely due to albumin proteins in MBPI-UFDF, absent in MBPI-IEP. Additionally, the MBPI-UFDF exhibited lower foam stability but higher gel firmness. Protein and peptide profiles after in vitro oral and gastric digestion were similar. Overall, proteolysis during intestinal digestion was more pronounced in MBPI-IEP. These findings highlight the importance of selecting the MBPI production process based on the desired food formulations, despite its low impact on in vitro digestibility.

This study aimed to evaluate the surface properties, secondary structures, solubilities, and gelling behaviors of purified mung bean globulins and albumins. The globulin fraction (88.44 % protein purity) was isolated by isoelectric precipitation from a mung bean protein isolate produced by ultrafiltration-diafiltration (UF-DF), while the albumin fraction (80.72 % protein purity) was purified from the soluble fraction using UF-DF. The albumin fraction maintained consistent solubility (similar to 50 %) from pH 2.0 to pH 8.0, whereas the globulin fraction exhibited a U-shaped solubility curve, with a marked decrease near its isoelectric point and maximum solubility at pH 8.0 (91.44 %). Albumins exhibited smaller particle sizes compared to globulins and were characterized by a significantly lower concentration of free sulfhydryl groups (5.79 vs 9.77 mu mol/mL). The albumin fraction had a lower minimum gelation concentration (4 %) compared to the globulin fraction (8 %), yet albumin gels formed weaker networks, with lower water retention (73.65 %) compared to globulin gels (93.59 %) at 8 % proteins. Rheological and microscopic analyses supported these findings, revealing a higher elastic modulus (G ') for globulin gels (8.91 Pa vs 1.08 Pa) and a denser microstructure, indicating stronger protein incorporation and more extensive intermolecular bonding. Globulin gels were formed primarily through hydrophobic interactions with no involvement of electrostatic or disulfide bonds. In contrast, albumin gels were formed mainly through electrostatic interactions, followed by hydrophobic interactions, and characterized by a high proportion of unbound proteins (25.5 %). Based on these results, mechanisms were proposed to illustrate the interactions and proteins involved in the formation of albumin and globulin gels.

The diversification of protein sources used in food formulation has increased the need to assess protein quality beyond traditional food forms. Protein digestibility is a key component of the Protein Digestibility Corrected Amino Acid Score (PDCAAS), the regulatory metric derived from rodent bioassays. Ethical concerns and the high cost of animal testing limit the ability of food formulators to screen protein ingredients and evaluate processing effects on digestibility. Findings from an international collaborative study are presented to position two in vitro methods, the pH-drop and pH-stat assays, as accredited approaches for determining protein digestibility. Nine laboratories participated in the study and analyzed 12 protein ingredients. Relative standard deviations for repeatability ranged from 0.8 to 2.1 % and 0.5-4.8 %, while reproducibility ranged from 1.2 to 3.6 % and 1.1-4.9 % for the pH-drop and pH-stat methods, respectively. Comparison between the two assays demonstrated strong correlation and moderate agreement, with the pH-stat assay yielding slightly lower digestibility values. In vitro protein digestibility coefficients aligned well with literature reported true faecal protein digestibility values for comparable, non-identical protein ingredients. Both methods received official AOCS Uniform Methods Committee approval, offering simple, affordable, reliable, and ethical tools to support informed decisions on protein digestibility during food formulation.

Buttermilk (BM) is a by-product of butter manufacturing that shares a similar composition to skim milk but contains a higher concentration of phospholipids due to milk fat globule membrane (MFGM) fragments released during cream churning. Despite its high added-value components, MFGM is underutilized mainly due to the challenge in separating its components from the other constituents of buttermilk. Our work has focused on the use of calcium phosphate particles, called hydroxyapatite (HA), to extract and separate the different components from buttermilk. This study investigated the impact of various physicochemical parameters (temperature, ionic strength, and pH) on the adsorption of a mixture of micellar casein (CM), whey proteins, and MFGM from BM onto HA surfaces. A box-Behnken design was utilized to predict optimal physicochemical conditions for selectively separating components in buttermilk. Ionic strength (IS) played a crucial role, with low IS having a minimal positive influence and high IS negatively influencing adsorption. pH influenced adsorption by altering protein and HA surface charges. The optimal conditions for adsorption were an IS of 100 mM for a pH of 7, for 90 % of CM, 37 % of (3-lactoglobulin, 11 % of a-lactalbumin and 7 % of MFGM. Desorption experiments using citrate and alkaline pH showed promising results for CM recovery, with citrate efficiently releasing the adsorbed CM. Additionally, MFGM were separated from whey proteins through selective precipitation at a pH of 4.0, allowing sedimentation of MFGM (100 %) while keeping whey proteins soluble. The presence of (3-lactoglobulin in the protein fraction of MFGM (31 %) and CM (37 %) was attributed to pasteurization, which denatured a portion of (3-lactoglobulin and led to its attachment to MFGM surfaces and interaction with CM. This protocol produces a nearly pure fraction of MFGM with a simple method which is suitable for industrial production, representing significant valorization for the dairy sector.

Palmitic acid (PA) supplementation and greater milking frequency can increase milk production and fat yield in dairy cows. However, the technological effects of those practices on cheesemaking still need to be determined. This work aimed to evaluate, with Holstein dairy cows, the effects of dietary PA, thrice-daily milking frequency, and their interaction on cheese yield and composition. Before cheesemaking, milks were standardized to a casein-to-fat ratio of 0.78% (SE: 0.02) and targets of 3.27% (SE: 0.03) and 4.20% (SE: 0.05). Rennet coagulation properties of standardized milk, cheese composition, curd draining properties, free fatty acid (FFA) content, and proteolysis during ripening were analyzed. Dietary PA supplementation modified the milk fatty acid profile but did not affect coagulation and draining properties, cheese composition, or proteolysis. The moisture-adjusted yield and fat and protein recoveries were also similar between treatments. The greater milking frequency did not affect process performance. However, increasing milking frequency led to a significantly higher FFA content in cheese at the end of ripening of 1.4 (SE: 0.2) mEq/kg versus 0.8 (SE: 0.2) mEq/kg of cheese fat for thrice- and twice-daily milkings, respectively. Consequently, dietary supplementation of PA to dairy cows had only a limited effect on the cheesemaking process under the standardized conditions tested. However, the effects of FFA on cheese sensory properties should be considered if the milking frequency is increased.

The suitability of a whey peptide hydrogel for entrapping curcumin compared with a whey protein isolate (WPI) gel was investigated. In addition, the release of curcumin entrapped in the peptide and protein gels was evaluated during static in vitro gastrointestinal digestion. The peptide hydrogel showed a 91% entrapment efficiency of curcumin compared with 99.9% for the WPI gel and at the end of intestinal digestion curcumin retention was close to 98% in the peptide hydrogel, whereas it was only 90% for the WPI gel. The preservation of the gel microstructure and, consequently, peptide-curcumin hydrophobic interactions during intestinal digestion could explain why curcumin release from the peptide hydrogel was lower than from the WPI gel. This work provides innovative results regarding the potential of using food-derived peptide hydrogels as an entrapment system for curcumin and its preservation during digestive conditions.(c) 2023 Elsevier Ltd. All rights reserved.

The impact of high hydrostatic pressure (HHP) on protein digestibility of egg yolk and egg yolk granule was evaluated by static in vitro digestion using the standardized INFOGEST 2.0 method. The degree of hydrolysis (DH) and the phospholipid content were determined during digestion, and the protein and peptide profiles were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse phase-high pressure liquid chromatography (RP-HPLC). The results showed that HHP induced protein aggregation in egg yolk and granule, mainly by disulfide bridges, which were not disrupted in the oral phase. Proteolysis during the gastric phase improved egg yolk and granule protein solubility, regardless of whether HHP was applied. However, the extent of the samples' digestibility was not affected, with DH values ranging from 15% to 20%. During the intestinal phase, the DH of egg yolk protein (∼40%) was higher than that of the granule (∼25%), probably due to the denser structure of the granule reducing the accessibility of intestinal enzymes. The DH, peptide, and protein profiles of control and HHP-treated egg yolk showed similar protein digestion behaviors for both gastric and intestinal phases. Among the different proteins, only the digestibility of β-phosvitin in HHP-treated granule was enhanced. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin with the potential to generate bioactive phosvitin-derived phosphopeptides. PRACTICAL APPLICATION: High hydrostatic pressure, mainly used as a preservation process, did not impair the nutritional quality of the egg yolk and granule proteins but improved the susceptibility of phosvitin (protein contained in egg yolk) proteolysis to produce bioactive phosphopeptides. Consequently, applying HHP to granules represents an interesting process that improves the digestibility of phosvitin.

This work aimed to study the performance of the UF-DF process, in terms of the permeation flux and membrane resistance, to produce a mealworm protein isolate. Moreover, a detailed characterization of the UF-DF retentates and permeates was performed. The results showed that the UF performances was reduced during the concentration phase, with a total flux decline close to 40 %. The membrane fouling was mainly reversible, and the flux was totally recovered during the DF. As expected, the ash content was drastically reduced in the retentate, but interestingly, low effects on the soluble sugars and lipids contents were noticed. The UF permeates were mainly composed of free amino acids and low molecular weight peptides, which confirms a high protein rejection of the UF membrane. Finally, compared to the protein concentrate before the UF-DF (57.29 %), the protein content increased by 26.4 % to reach 72.40 % which validates the feasibility of producing mealworm protein isolates using filtration parameters described in this work. This study demonstrated the potential of using UF-DF to produce a mealworm protein isolate with a complete amino acid profile rich in essential amino acids.

Egg yolk granule is a promising ingredient in the food industry. Recent studies have shown that ultra-high pressure homogenization (UHPH) improved the techno-functional properties of the granule, but they did not evaluate its impact on digestibility. Consequently, this work aimed to evaluate the impact of UHPH-treatment (300 MPa and 4 passes) on granule digestibility by using a static in vitro digestion method. While UHPH destabilized the high molecular weight granule lipoproteins, the treatment did not affect the in vitro digestibility of egg yolk granule since similar protein/peptide profiles were obtained from gel electrophoresis and RP-HPLC analysis. Moreover, the degree of hydrolysis was similar between control and UHPH-treated granules with values ranging from 11.5 to 25.2% for the gastric and intestinal phases, respectively. Finally, apovitellin 3-4, apovitellenin IV and phosvitin were specifically digested during the gastric and intestinal phases. Consequently, modifications induced by UHPH on egg yolk granule were not correlated with in vitro digestion experiments. Nevertheless, this work represents an interesting added-value to support the development of innovative egg yolk granule-based ingredients for the food industry.

To meet the high consumer demand, butter production has increased over the last few years. As a result, the buttermilk (BM) co-produced volumes require new ways of adding value, such as in cheese manufacturing. However, BM use in cheese milk negatively influences the cheesemaking process (e.g., altered coagulation properties) and the product's final quality (e.g., high moisture content). The concentration of BM by ultrafiltration (UF) could potentially facilitate its use in cheese manufacturing through an increased protein content while maintaining the milk salt balance. Simultaneously, little is known about the digestion of UF BM cheese. Therefore, this study aimed to characterize the impact of UF BM on cheese manufacture, its structure, and its behavior during in vitro digestion. A 2-fold UF concentrated BM was used for cheese manufacture (skim milk [SM] - control). Compositional, textural, and microstructural analyses of cheeses were first conducted. In a second step, the cheeses were fed into an in vitro TNO gastrointestinal digestion model (TIM-1) of the stomach and small intestine and protein and phospholipid (PL) bioaccessibility was studied. The results showed that UF BM cheese significantly differed from SM cheese regarding its composition, hardness (p < 0.05) and microstructure. However, in TIM-1, UF BM and SM cheeses showed similar digestion behavior as a percentage of protein and PL intake. Despite relatively more non-digested and non-absorbed PL in the ileum efflux of UF BM cheese, the initially higher PL concentration contributes to an enhanced nutritional value compared to SM cheese. To our knowledge, this study is the first to compare the bioaccessibility of proteins and PL from UF BM and SM cheeses.

Buttermilk differs from skim milk by the presence of milk fat globule membrane (MFGM) fragments that are released during cream churning. MFGM is rich in health-promoting components, such as phospholipids and membrane proteins, but these compounds have a negative impact on buttermilk techno-functional properties in dairy applications. The isolation of MFGM from buttermilk improved its functionality while also recovering the MFGM bioactive components. Hydroxyapatite (HA) can be used to extract MFGM by adsorption via charged site interactions. However, the affinity of HA to MFGM or the main buttermilk proteins (casein micelles (CM), β-lactoglobulin (β-lg) and α-lactalbumin (α-lac)) is not known. The influence of important physicochemical parameters such as pH and temperature on these interactions is also unclear. For each buttermilk component, a quartz crystal microbalance diffusion analysis was performed to determine the maximum adsorption time and the attached mass density on HA-coated gold sensors. The influence of pH, ionic strength (IS), and temperature (T) on the affinity of each buttermilk component for HA particles was assessed using a 3-levels and 3-factors Box-Behnken design. The absorption rate was highest for the CM, followed by β-lg and α-lac, and then by the MFGM. Nevertheless, the final maximal attached mass densities to the HA were similar for the MFGM and CM, and 2.5 times higher than for β-lg and α-lac. This difference can be explained by the higher number of binding sites found in CM and their heavier mass. The model obtained by the Box-Behnken design plan showed that the adsorption of the CM changed with T, pH and IS. These results suggest that the techno-functional properties of buttermilk may be restored by specifically extracting MFGM with HA. Experiments are ongoing to determine conditions for fractionating MFGM directly from buttermilk.

Buttermilk (BM) is still undervalued since its incorporation in dairy products negatively impairs physicochemical properties. Concentrating BM could mitigate these adverse outcomes. This study aimed to characterize the impact of 2-fold BM concentration by reverse osmosis (RO) and ultrafiltration (UF) on the rennet-induced gelling characteristics of milk containing varying BM to skim milk (SM) ratios. Oscillatory rheology was used to determine the gel coagulation properties (rennet coagulation time [RCT], storage modulus [G'] at 2 x RCT, maximal firming rate [MFR]), and the gelation regime by determining the fractal dimension (df). Increasing BM protein concentration enhanced rennet gel G ' and MFR. Increasing the ratio of BM to SM significantly decreased the G ' and MFR values. The df values increased from 2.69 for non-concentrated BM, to 2.76 for RO, and to 2.88 for UF, indicating that the gel density increased, whereas the casein (CN) aggregates decreased in size. CLSM and SEM observations also showed a higher CN particle's packing density in UF gels compared to non-concentrated and RO gels. Application of the gel regime model revealed that all gels were in the transition regime. This result contrasted with the microscopy and df values. We conclude that while the df values are a good representation of the gel structure, the gel regime characterization is not, and the model cannot be applied to complex milk rennet gels. This study provides a new rheological characterization of BM rennet gels. UF of BM enhanced rennet gel formation and might facilitate the use of BM in cheese making.

Peptide-based hydrogels, typically mediated by non-covalent interactions, are becoming increasingly attractive due to their many biotechnological applications such as drug and antimicrobial delivery, as well as tissue en-gineering. In our previous work, we demonstrated that specific peptide fractions from beta-lactoglobulin (B-Lg) could form hydrogels either by peptide-peptide interaction or through peptide self-assembly of B-Lg f1-8, depending on the purity of B-Lg f1-8 in peptide fractions. However, mechanisms that govern hydrogel forma-tion were not investigated. Consequently, this study focused on the impact of peptide fraction (pellet) concen-tration, temperature, pH and B-Lg f1-8 concentration on hydrogel formation. Moreover, contribution of peptides B-Lg f15-20 and B-Lg f41-60 to hydrogel formation was determined. We hypothesized that hydrogel formation results from a balance between hydrogen, hydrophobic and electrostatic interactions during gelation at a con-centration of 50 mg/mL, 20 degrees C and pH close to 11. The peptide B-Lg f1-8 was shown to initiate the gelation by increasing the density of nanofibers in a concentration-dependent manner which promoted peptide-peptide in-teractions. Finally, interactions between both B-Lg f15-20 and B-Lg f41-60 peptides and B-Lg f1-8 occurred during gel formation negatively impacted the self-assembly process. The proposed mechanism for B-Lg f1-8 gelation would facilitate the development of functional soft biomaterials and bioactive encapsulation systems.

The impact of ultra-high pressure homogenization (UHPH) (175 and 300 MPa, 1 and 4 passes) on the structure of egg yolk granule was evaluated to improve the techno-functional properties of the proteins. The UHPH treatment destabilized and modified the structure of egg yolk granule proteins, which was validated by protein profiles from gel electrophoresis. A decrease of free thiol and an increase of disulfide bond content was correlated with a decrease of the surface hydrophobicity, specifically at 300 MPa with 4 passes. The structural modifications induced by UHPH, mainly at 300 MPa (1 and 4 passes), improved the water and oil binding capacities of egg yolk granules with values ranging from 1.30 to 1.55 gwater/ggranule and 3.34 to 3.73 goil/ggranule, respectively as well as their stability index. However, egg yolk granule solubility was not impacted by the application of UHPH. These new insights are key to supporting the development of new egg yolk granule-based ingredients for the food industry.

Buttermilk (BM), the by-product of butter making, is similar to skim milk (SM) composition. However, it is currently undervalued in dairy processing because it is responsible for texture defects (e.g., crumbliness, decreased firmness) in cheese and yogurt. One possible way of improving the incorporation of BM into dairy products is by the use of technological pretreatments such as membrane filtration and homogenization. The study aimed at characterizing the effect of preconcentration by reverse osmosis (RO) and single-pass ultra-high-pressure homogenization (UHPH) on the composition and microstructure of sweet BM to modify its techno-functional properties (e.g., protein gel formation, syneresis, firmness). The BM and RO BM were treated at 0, 15, 150, and 300 MPa. Pressure-treated and control BM and RO BM were ultracentrifuged to fractionate them into the following 3 fractions: a supernatant soluble fraction (top layer), a colloidal fraction consisting of a cloudy layer (middle layer), and a high-density pellet (bottom layer). Compositional changes in the soluble fraction [lipid, phospholipid (PL), protein, and salt], as well as its protein profile by PAGE analysis, were determined. Modifications in particle size distribution upon UHPH were monitored by laser diffraction in the presence and absence of sodium citrate to dissociate the casein (CN) micelles. Microstructural changes in pressure-treated and non-pressure-treated BM and RO BM particles were monitored by confocal laser scanning microscopy. Particle size analysis showed that UHPH treatment significantly decreased the size of the milk fat globule membrane fragments in BM and RO BM. Also, pressure treatment at 300 MPa led to a significant increase in the recovery of total lipids, CN, calcium, and phosphate in the BM soluble fraction (top layer) following ultracentrifugation. However, PL were primarily concentrated in the pellet cloud (middle layer), located above the pellet in BM concentrated by RO. In contrast, PL were evenly distributed between soluble and colloidal phases of BM. This study provides insight into the modifications of sweet BM constituents induced by RO and UHPH from a compositional and structural perspective.

The milk fat globule membrane (MFGM), which surrounds and stabilizes the fat globules, is released in buttermilk during cream churning. MFGM has many health benefits due to its composition rich in phospholipids and membrane proteins. Many techniques have been tried to separate the MFGM from the remaining milk solids non-fat, but they are challenging to carry out at an industrial scale. This research proposes a new approach to separating MFGM from buttermilk. This paper assessed the efficacy of hydroxyapatite (HA) cristal in interacting with MFGM isolates obtained from either raw or pasteurized cream. Different HA to MFGM ratios were used (10:1 and 20:1) to determine the impact of HA concentration on the adsorption. The results showed a very high affinity of the MFGM for HA and suggested the potential for its separation from buttermilk to improve its valorization.