Search Results (67)

This study assessed the effect of ultrafiltration (UF) on the quality of soft white cheese made from goat skim milk (GSM) and aimed to identify the optimal UF parameters for protein concentration while minimizing energy consumption. UF was applied to pasteurized GSM by altering transmembrane pressure (TMP) and permeate flux density (J) while monitoring the volume reduction factor (VRF). The acidity, viscosity, dry extract, proteins and Ca, Na, K, Mg and Fe contents increased significantly during concentration. Post-ultrafiltration, both UF and non-UF GSMs were coagulated using modified rennet doses (150, 200 and 300 µL/L). The resulting cheeses underwent chemical analysis, yield calculation and textural property assessment. The findings highlighted that milk protein concentration was the primary limiting factor for coagulation, with rennet dose having a lesser impact. The UF-GSM produced the best results, yielding approximately 30% cheese with a soft texture and greater nutritional value (proteins, Ca, Mg and Fe). Full article

Bovine milk protein preparations (MPPs), namely micellar casein concentrate (MCC), serum protein concentrate (SPC), and MCC with ultrafiltrated buttermilk permeate (MBP), were analyzed as sources of inhibitors of angiotensin-converting enzyme (i.e., ACE) and dipeptidylpeptidase IV (i.e., DPP-IV) as well as antioxidative peptides. The studies involved in silico predictions of the release of biopeptides from bovine milk proteins. Then, all MPPs were subjected to the simulated gastrointestinal digestion using the INFOGEST protocol. Results using a BIOPEP-UWM database tool indicated that 59 biopeptides exhibiting the above-mentioned activities could be produced upon the action of pepsin, trypsin, and chymotrypsin. Thirty-six biopeptides were identified in at least one of the three MPPs subjected to the INFOGEST protocol. MCC before simulated digestion exhibited the strongest ACE-inhibiting activity among all MPPs (IC₅₀ = 1.856 mg/mL). The weakest ACE inhibitory effect was demonstrated for MBP after duodenal digestion (i.e., MBP D; IC₅₀ = 7.627 mg/mL). The above MPP showed the strongest DPP-IV-inhibiting activity (IC₅₀ = 0.0067 mg/mL). All MPPs exhibited antioxidative activity, with the strongest ABTS^•+ (i.e., 2,2′-azino-bis(3-ethylbenzotialozline-6-sulfonic acid) radical scavenging effect shown for MBP D (IC₅₀ = 2.754 mg/mL), and the strongest DPPH^• (i.e., 2,2-diphenyl-β-picrylhydrazyl) radical scavenging activity (IC₅₀ = 1.238 mg/mL) demonstrated for SPC D. Among all MPPs, SPC D also exhibited the highest FRAP (i.e., Ferric Reducing Antioxidant Power) bioactivity (IC₅₀ = 13.720 mg/mL), whereas MBP D was the MPP with the lowest FRAP potential (IC₅₀ = 20.140 mg/mL). The present study results show the potential of all MPPs as functional additives to support health-beneficial functions of dairy products. Full article

The objective of this study was to investigate the impact of thermal and homogenization pre-treatments on ultrafiltration (UF) efficiency and component retention in whole milk (WM). Four milk treatments were examined using a benchtop Optisep filtration system: skim milk (SM) processed in UF at 15 °C, homogenized WM processed in UF at 15 °C (T1), non-homogenized WM processed in UF at 15 °C (T2), and non-homogenized WM processed at 43 °C (T3). UF was performed using 10 kDa membranes to achieve 3× concentration, and the retention and flux rates were compared across treatments. Compositional changes were analyzed at each stage: initial, retentate (2X, 3X, Final), and permeate. The permeate flux varied across treatments; SM showed the highest initial permeate flux and achieved the target concentration in a shorter time. T1 maintained a steady permeate flux over time. T2 exhibited a steep decline in flux, reaching only a 2.5× concentration. In contrast, T3 initially displayed a higher permeate flux due to heat treatment and reduced viscosity. There were significant differences in compositional parameters. T1 retentate had significantly (p < 0.05) higher crude protein (CP), Ca, Mg, and Zn retention. Higher total solids (TS), non-protein nitrogen (NPN), and non-casein nitrogen (NCN), K, and P content were found in T3 permeate. The results from this study demonstrate that homogenization and heat treatment significantly impact the UF performance of WM, offering valuable approaches for achieving dairy product composition. Full article

In milk, casein proteins orientate themselves into spherical micellar structures with hydrophobic casein subtypes concentrated in the core, while hydrophilic casein subtypes populate the exterior. Previous research demonstrated that milk with the addition of emulsifying salts coupled with high-pressure homogenization induced an unprecedented amount of casein micelle dissociation. This research aims to quantify the extent of casein micelle dissociation in diluted skim milk and evaluate the functionality of these proteins following emulsifying salt treatment coupled with high-pressure homogenization. To evaluate the extent of micellar dissociation, dilute skim milk solutions (20% v/v) were prepared with a varying amount of treatment: no processing (control), just emulsifying salts (Treatment E, 100 mM sodium hexametaphosphate), just high-pressure homogenization (Treatment H, at 300 MPa), and EH (a combination of E and H treatments). Samples were then put through varying filter sizes (0.22 µm, 0.05 µm), and the permeates were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In the control group (20% skim milk), 9.35% ± 2.53% casein protein permeated through a 0.05 µm filter. Alternatively, 93.2% ± 7.71% casein protein was present in EH samples post-filtration through a 0.05 µm filter, demonstrating a significant processing-induced dissociation of casein micelles. A potential benefit to this casein micelle size reduction is the exposure of highly functional hydrophobic subunits from the core of the micelle. In agreement, compared to the control samples, the EH samples had higher foam expansion index values (138.3% ± 12.58% vs. 33.33% ± 14.43% at 0 h), foam stability (113.3% ± 5.774% vs. 21.67% ± 2.887% after 8 h), emulsifying activity (ca. two-fold higher), and interaction with caffeine. These data demonstrate that E, coupled with H, enhances skim milk system functionality, and these changes are likely due to micellar dissociation and protein conformational changes. This work has direct applications in dairy systems (e.g., dairy foams, dairy ingredients) as well as implications for potential processing strategies for other protein-rich systems. Full article

In this study, five distinct industrial waste streams, encompassing bakery processing and kitchen waste (BP plus KW) mixture, fat, oil, and grease (FOG), ultrafiltered milk permeate (UFMP), powder whey (PW), and pulp and paper (PP) compost, underwent mesophilic biochemical methane potential (BMP) assays at F/M ratios of 1, 2, 4, and 6 g COD/g VSS. An F/M ratio of 1 g COD/g VSS showed the highest methane yield across the investigated feedstocks. In the case of UFMP and PW, an F/M ratio of 2 produced identical results to an F/M ratio of 1 despite their relatively high carbohydrate content which is easily acidified to VFAs. Increasing the F/M ratio to 2 decreased the biodegradability of both BP plus KW and FOG by 63%. Increasing the F/M ratio of the PP did not show as much of a significant impact on biodegradability compared to the other feedstocks as methane yields decreased from 135 to 92 mL CH₄/g COD, a decrease of 32%. Full article

The shear flow and solid–liquid transition of mixed milk protein dispersions with varying concentrations of casein micelles (CMs) and serum proteins (SPs) are integral to key dairy processing operations, including microfiltration, ultrafiltration, diafiltration, and concentration–evaporation. However, the rheological behavior of these dispersions has not been sufficiently studied. In the present work, dispersions of CMs and SPs with total protein weight fractions (ω_PR) of 0.021–0.28 and SP to total protein weight ratios (R_SP) of 0.066–0.214 and 1 were prepared by dispersing the respective protein isolates in the permeate from skim milk ultrafiltration and then further concentrated via osmotic compression. The partition of SPs between the CMs and the dispersion medium was assessed by measuring the dry matter content and viscosity of the dispersion medium after separating it from the CMs via ultracentrifugation. The rheological properties were studied at 20 °C via shear rheometry, and the sol–gel transition was characterized via oscillatory measurements. No absorption of SPs by CMs was observed in dispersions with ω_PR = 0.083–0.126, regardless of the R_SP. For dispersions of SPs with ω_PR ≤ 0.21, as well as the dispersion medium of mixed dispersions with ω_PR = 0.083–0.126, the high shear- rate-limiting viscosity was described using Lee’s equation with an SP voluminosity (v_SP) of 2.09 mL·g⁻¹. For the mixed dispersions with a CM volume fraction of φ_CM ≤ 0.37, the relative high shear-rate-limiting viscosity was described using Lee’s equation with a CM voluminosity (v_CM) of 4.15 mL·g⁻¹ and a v_SP of 2.09 mL·g⁻¹, regardless of the R_SP. For the mixed dispersions with φ_CM > 0.55, the relative viscosity increased significantly with an increasing R_SP (this was explained by an increase in repulsion between CMs). However, the sol–gel transition was independent of the R_SP and was observed at φ_CM ≈ 0.65. Full article

The salt fractions of milk consist of cations (e.g., Ca, Mg, and Na) and anions (e.g., phosphate, citrate, and chloride). These salts are present as free ions or in complexes with other ions or proteins, primarily the caseins. Furthermore, significant levels of Ca and phosphate are also found in insoluble form, inside the casein micelles. The distribution of salts between this micellar phase and the soluble phase is important for the stability and properties of milk and dairy products. Various processes, such as (ultra-)centrifugation, (ultra-)filtration, dialysis, and selective precipitation have been used to separate the micellar and soluble phases in milk and dairy products to allow for studying the salts’ distribution between these phases. These different methods can lead to different levels of soluble salts because the salts in the supernatant from centrifugation, the permeate from ultrafiltration, and the diffusate from dialysis can differ notably. Hence, understanding which components are fractionated with these techniques and how this affects the levels of the soluble salts determined is critical for milk and dairy products. Applying the aforementioned methods to cheese products is further challenging because these methods are primarily developed for fractionating the soluble and micellar phases of milk. Instead, methods that analyze salts in water-soluble extracts, or soluble phases expressed from cheese by pressing or centrifugation are typically used. This review focuses on the significance of salt distribution and variations in salt fractions obtained using different methodologies for both milk and cheese. Full article

Edible insects represent a growing sector of the food industry and have a low carbon footprint. Noteworthy, insects can upcycle different leftovers and byproducts into high-quality nutrients. Herein, the larvae of the edible insect Tenebrio molitor (TML) were fed using local milk industry byproducts. Mozzarella whey and whey permeate obtained in cheese production were used to formulate three alternative diets. Both byproducts are rich in sugars, in particular the disaccharide lactose and the monosaccharides glucose and galactose. Two of the three diets did not interfere with biometric data and vitality, while the use of whey permeate alone significantly reduced development. At the end of the trial, the proximate composition of TML was strongly affected, with an increased protein content of up to +7% and a favorable fat composition. The analysis of secondary metabolites revealed the accumulation of different compounds, in particular monounsaturated fatty acids (MUFAs), amino acids, and the disaccharide trehalose, essential for the correct larval development and pupation. In conclusion, the present study demonstrates that milk industry byproducts can be upcycled as feed for TML, maintaining an optimal nutrient composition and favorably increasing the protein content. Full article

This study investigated the production of rennet gels from β-casein-depleted retentates obtained through cold microfiltration (MF) of skim milk (SM) that was treated beforehand to ensure microbial safety. The treatments included thermization (65 °C, 20 s), pasteurization (72 °C, 15 s), and microfiltration (50 °C; 1.4 μm pore size). The reduction in β-casein content was 0.98, 0.51 and 0.90%, respectively. All treatments resulted in the partial aggregation of serum proteins, which were slightly concentrated in the retentates obtained post cold MF process. This aggregation, along with concentration effect, likely inhibited β-casein dissociation from casein micelles and permeation, particularly in pasteurized milk. Renneting and coagulation properties of the retentates were comparable to those of the respective SM samples, with no significant differences in syneresis, water-holding capacity, or protein hydration. Notably, the retentate from thermized SM, which showed the best performance with the highest β-casein reduction (0.98%), demonstrated shorter coagulation time compared to retentate from pasteurized milk or the corresponding unfiltered SM. Textural analysis revealed greater firmness, cohesiveness, and viscosity of retentate-based rennet gels compared to gels made from unfiltered SM, attributed to protein concentration during cold MF. Overall, this study successfully produced rennet gels from cold MF retentates without compromising their physicochemical properties. Full article

The discarding of agri-food by-products is a stringent problem due to their high environmental impact. Recovery strategies can lead to a reduction of waste and result in new applications. Agri-food waste represents a source of bioactive molecules, which could promote health benefits. The primary goal of this research has been the assessment of the antioxidant activity of milk permeate, a dairy farm by-product, and the isolation and identification of peptide fractions endowed with antioxidant activity. The chromatographic extraction of the peptide fractions was carried out, and the peptides were identified by mass spectrometry. The fractions showed radical scavenging activity in vitro. Moreover, the results in the Caco-2 cell model demonstrated that the peptide fractions were able to protect from oxidative stress by stimulating the Keap1/Nrf2 antioxidant signaling pathway, increasing the transcription of antioxidant enzymes. In addition, the bioactive peptides can affect cellular metabolism, increasing mitochondrial respiration. The action of the peptide fractions was also assessed in vivo on a zebrafish model and resulted in the protection of the whole organism from the adverse effects of acute cold stress, highlighting their strong capability to protect from an oxidative insult. Altogether, the results unveil novel recovery strategies for food by-products as sources of antioxidant bioactive peptides that might be utilized for the development of functional foods. Full article

Organic-rich industrial residues can serve as renewable feedstocks for the generation of useful products by microbial fermentation. We investigated fermenting communities enriched in a mixture of ultra-filtered milk permeate (UFMP) and acid whey from cottage cheese (CAW), two dairy coproducts rich in lactose. To evaluate how operational pH and temperature affect microbial communities and fermentation products, we operated 12 bioreactors for 140 days, each fed a 1:1 mixture of UFMP and CAW at either 35 °C or 50 °C and at either a pH of 4.8 or 5.5. The bioreactors operated at a pH of 4.8 resulted in the incomplete conversion of lactose, while those operated at a pH of 5.5 consistently fermented lactose, primarily into lactic, acetic, and hexanoic acids. The metagenomic analyses revealed that microbial communities obtained at a pH of 5.5 were dominated by lactic acid-producing organisms. Additionally, an inverse relationship was found between the abundance of chain elongating organisms and lactic acid accumulation, with 50 °C reducing the abundance of these organisms and enhancing lactic acid yields. We conclude that the pH and temperature are important determinants of the fermentation of dairy coproducts with a pH of 5.5 and 50 °C yielding the most promising results for lactic acid production. Additional research is required to better understand the factors affecting functional consistency of the process. Full article

Delivery represents a major hurdle to the clinical advancement of oligonucleotide therapeutics for the treatment of disorders such as Duchenne muscular dystrophy (DMD). In this preliminary study, we explored the ability of 2′-O-methyl-phosphorothioate antisense oligonucleotides (ASOs) conjugated with lipophilic ursodeoxycholic acid (UDCA) to permeate across intestinal barriers in vitro by a co-culture system of non-contacting IEC-6 cells and DMD myotubes, either alone or encapsulated in exosomes. UDCA was used to enhance the lipophilicity and membrane permeability of ASOs, potentially improving oral bioavailability. Exosomes were employed due to their biocompatibility and ability to deliver therapeutic cargo across biological barriers. Exon skipping was evaluated in the DMD myotubes to reveal the targeting efficiency. Exosomes extracted from milk and wild-type myotubes loaded with 5′-UDC-3′Cy3-ASO and seeded directly on DMD myotubes appear able to fuse to myotubes and induce exon skipping, up to ~20%. Permeation studies using the co-culture system were performed with 5′-UDC-3′Cy3-ASO 51 alone or loaded in milk-derived exosomes. In this setting, only gymnotic delivery induced significant levels of exon skipping (almost 30%) implying a possible role of the intestinal cells in enhancing delivery of ASOs. These results warrant further investigations to elucidate the delivery of ASOs by gymnosis or exosomes. Full article

The study aims to improve the quality of wooden breast meat (WBM) via the use of newly developed marinades based on selected strains of lactic acid bacteria (LAB) in combination with the by-products of the dairy and fruit/berry industries. Six distinct marinades were produced based on milk permeate (MP) fermented with Lacticaseibacillus casei (Lc) and Liquorilactobacillus uvarum (Lu) with the addition of apple (ApBp) and blackcurrant (BcBp) processing by-products. The microbiological and acidity parameters of the fermented marinades were evaluated. The effects of marinades on the microbiological, technical, and physicochemical properties of meat were assessed following 24 and 48 h of WBM treatment. It was established that LAB viable counts in marinades were higher than 7.00 log₁₀ colony-forming units (CFU)/mL and, after 48 h of marination, enterobacteria and molds/yeasts in WBM were absent. Marinated (24 and 48 h) WBM showed lower dry-matter and protein content, as well as water holding capacity, and exhibited higher drip loss (by 8.76%) and cooking loss (by 12.3%) in comparison with controls. After WBM treatment, biogenic amines decreased; besides, the absence of spermidine and phenylethylamine was observed in meat marinated for 48 h with a marinade prepared with Lu. Overall, this study highlights the potential advantages of the developed sustainable marinades in enhancing the safety and quality attributes of WBM. Full article

Background: An earlier study showed different metabolic responses to intake of an acute calcium load from milk-derived calcium permeate (CP) and calcium carbonate (CC). The long-term and clinical implications for bone maintenance are unknown. Objective: To investigate the effects of 12-month supplementation with CP, taken alone or in conjunction with inulin, on changes in bone mass density (BMD) and bone turnover markers (BTMs) in apparently healthy postmenopausal women compared with CC or placebo. Methods: A 12-month randomized controlled double-blinded multi-center intervention trial was conducted with healthy postmenopausal women with adequate vitamin D status. During the trial, participants received maltodextrin (placebo), 800 mg calcium as CC, or 800 mg calcium as CP (Capolac^®MM-0525 BG, Arla Foods Ingredients Group P/S, Viby J, Denmark) without or with 12 mg of inulin and divided into two daily doses of capsules and sachets. A daily vitamin D supplement of 20 µg was provided. At baseline and at the end of the study, BMD was assessed by DXA scan, and anthropometric measures were obtained together with fasting blood samples for measurements of BTMs (CTX and P1NP), serum iPTH, vitamin D, serum calcium, creatinine, phosphate, and triglycerides. Habitual dietary intake was assessed using the online system Myfood24, where subjects recorded their dietary intake for 7 consecutive days, and physical activity was assessed by the International Physical Activity Questionnaire. Socioeconomic data and physical activity were obtained through questionnaires. Preliminary results: A total of 417 women were eligible according to the inclusion and exclusion criteria and were included over a 12-month period. At present, 239 subjects have completed the study. The intervention will end in June 2023. Baseline characteristics (mean ± SD) are age 55.4 ± 4.17 years; height 167.4 ± 5.73 m; body weight 71.5 ± 11.7 kg; BMI 25.5 ± 3.78; hip circumference 102.3 ± 9.48 cm; and waist circumference 84.09 ± 10.0 cm. The BMDs expressed as t-scores were L-total −0.46 ± 1.17 and Neck-total −0.88 ± 0.80. Discussion: The recruitment of eligible participants was delayed due to COVID but was successful within one year. The drop-out rate has been larger than expected. More results will be ready to be presented at the conference. Full article

The goal of this research was to study the factors influencing the in vitro transdermal penetration of nicotinamide and to establish an evaluation method for the in vitro transdermal absorption of nicotinamide. The permeability of nicotinamide was investigated with Franz diffusion cell in vitro transcutaneous assays, and the effect of the receiving solution composition, receiving solution pH, skin type, diffusion cell temperature, active ingredient concentration, supply quantity, and product dosage form on its permeation was investigated separately by high-performance liquid chromatography. The best assay for the transdermal absorption of nicotinamide was established—there was a better transdermal absorption performance, more stable system, better applicability, and better reproducibility when the receiving solution was PBS (phosphate-buffered saline) solution, the pH was 7.4, the membrane was pig ear skin, the temperature was 37 °C, the concentration of nicotinamide was 3%, and the dose of the test substance was 2 g. In the three cosmetic dosage forms of toning lotion, milk lotion, and gel, the permeability of milk lotion was the highest, followed by toning lotion and gel. Full article