Search Results (158)

The rapid expansion of high-protein dairy-based powders (HPDPs), including milk protein concentrates and isolates (MPC/MPI), whey protein concentrates and isolates (WPC/WPI), and micellar casein concentrates and isolates (MCC/MCI), has intensified the need to understand instability phenomena that emerge during processing and storage. These products are governed by protein-rich amorphous matrices, in which molecular mobility, interfacial composition, and mineral interactions dictate both physical stability and functional performance. Importantly, these physical instabilities are directly coupled with functional deterioration, particularly in terms of impaired wetting, dispersion, and dissolution during rehydration. This review presents an integrated mechanistic framework linking these instability phenomena across processing, storage, and reconstitution, thereby consolidating concepts that remain fragmented across the current literature on high-protein dairy matrices. Key controlling factors include glass transition temperature (Tg), water activity-induced plasticization, protein–protein and protein–mineral interactions, and surface compositional heterogeneity established during spray drying. These factors govern the progression from surface stickiness through uncontrolled agglomeration to caking, forming a consolidation continuum. In contrast to lactose-driven matrices, caking and agglomeration in HPDPs arise primarily from protein-mediated restructuring and inter-particle bonding, with lactose crystallization acting only as a secondary mechanism in mixed-composition grades. The review further distinguishes engineered agglomeration from storage-induced consolidation and evaluates advances in molecular mobility characterization and Tg-based stability mapping. Significant gaps remain in linking localized surface evolution, mineral redistribution, and inter-particle bridge chemistry under realistic environmental conditions. The review concludes by proposing a mobility-centered “stability-by-design” framework that integrates composition, processing, particle architecture, and storage conditions to guide the development of future HPDPs with improved physical stability and functional recovery. Full article

In Mexico, cheese whey (CW) is commonly treated as a dairy wastewater despite its high lactose and nutrient content. This study evaluated cheese whey (CW) and ultrafiltered cheese whey (UF-CW) as low-cost substrates for the cultivation of the probiotic strains Lactobacillus acidophilus and Lactococcus lactis. The proposed bioprocess simultaneously enables the production of probiotic biomass and lactic acid, a high-value platform chemical with broad applications in the food, pharmaceutical, and biopolymer industries. In the first experimental trials, in which CW and UF-CW were used solely as media, fermentations lasted 36 h at 30 and 37 °C, with initial pH levels of 5 and 7. CW demonstrated a greater capacity to support the growth of lactic acid bacteria. Thus, to increase the fermentative capability of UF-CW, it was supplemented with yeast extract (YE) or corn steep liquor (CSL), and CaCO₃ was added to stabilize pH, as low pH values inhibit growth and lactic acid production. The proposed strategy notably improved microbial growth in UF-CW, increasing Lc. lactis and L. acidophilus populations from 8.3 and 8.2 Log₁₀ CFU/mL to 9.3 Log₁₀ CFU/mL, respectively. The findings suggest that dairy wastewater can be effectively repurposed as a low-cost cultivation medium for these bacteria. ASPEN simulation analyses demonstrated that lactose conversion efficiency and final product concentration were key factors affecting process performance and economic feasibility. Among the evaluated scenarios, a 45% lactose-to-lactic acid conversion yielded the most economically favorable process performance compared with conversions of 10% and 25%. Future research should focus on enhancing fermentation yields and adopting more efficient downstream recovery techniques. Full article

Cheese production generates large volumes of whey, and high-strength wastewater with elevated organic load, salinity, and nutrient content. Although whey contains valuable components including lactose, proteins, and minerals, approximately half of global production remains underutilized, contributing to eutrophication and oxygen depletion in aquatic ecosystems. Conventional physicochemical and biological treatment methods are limited by high operational costs, energy demands, and secondary waste generation. Microalgae-based bioremediation has emerged as a promising sustainable strategy for whey valorization, enabling simultaneous nutrient removal and biomass production. Through a focused review of the current literature, this study analyzes microalgal strains commonly applied in whey remediation, their cultivation modes (photoautotrophic, heterotrophic, and mixotrophic), nutrient uptake mechanisms, and operational conditions. The review highlights cultivation systems, biomass recovery techniques, and potential conversion of microalgal biomass into high value bioproducts, including biofuels, pigments, proteins, and biofertilizers. Critically, a major research gap exists: no studies systematically examine whey-grown microalgal biomass for bioplastic or film production, despite its elevated polysaccharide and protein content. Future development requires integrated biorefinery approaches, optimized cultivation strategies, and supportive policy frameworks to enable large-scale circular economy implementation within the dairy industry. Full article

The valorization of dairy by-products, particularly whey, represents a key challenge and opportunity in sustainable food systems. This study aimed to evaluate the physicochemical and amino acid composition of milk and whey-derived products and to identify optimal whey–milk mixtures using integrated multivariate and desirability-based approaches. Ten model systems (M1–M10) were prepared with increasing whey content (7.5–75%), and their composition was analyzed using infrared spectroscopy and high-performance liquid chromatography. Multivariate analysis, including PCA and correlation heatmaps, revealed that protein, casein, TS, SNF, and amino acid fractions (ΣEAA and ΣBCAA) were the primary drivers of compositional variability, whereas lactose and acidity-related parameters contributed to secondary differentiation. Desirability function analysis was applied by integrating nutritional quality, functional balance, and sustainability score into a composite index. The results demonstrated that intermediate formulations achieved a more balanced profile compared with extreme compositions. Among all mixtures, the formulation containing 30% whey (M5) showed the highest overall desirability within the evaluated parameters, reflecting a favorable balance between compositional quality and whey utilization. These findings highlight the potential of integrated analytical approaches for the development of nutritionally optimized and resource-efficient dairy systems. Full article

Making 1 $\mathrm{k}$$\mathrm{t}$ of cheese produces 9 $\mathrm{k}$$\mathrm{t}$ of cheese whey permeate, a waste with 5% lactose, which is either discarded or dried for animal feed. One pathway to add value to this waste is to convert it to lactic acid (LA), a monomer for polylactic acid, the largest bioplastic produced in the world. Lactose hydrolyses to glucose and galactose. While Brønsted acidity enhances lactose hydrolysis, Lewis acidity favours the formation of lactic acid. For the first time, we tested both industrial whey permeate and purified lactose as feedstocks for LA over a heterogeneous catalyst–Er₂O₃/Al₂O₃. LA Yield from whey permeate reached 14%, while the maximum yield with purified lactose was 22%. LA yield was invariant with respect to mixing speed while increasing temperature accelerates the time it takes to reach quasi-equilibrium. Yield was also independent of pressure with either air, He, N₂, or H₂ in the vapour space above the liquid phase in the autoclave. LA yield over spent catalyst with fresh lactose was only 11%, which indicates that the catalyst deactivates. Based on XRF analyses, the Er₂O₃ mass fraction dropped from 15% to 5%, with 6.4% leaching into the aqueous phase after the first step but only 0.8% after the second test. Full article

Kefiran is a bioactive exopolysaccharide produced by kefir grains, whose synthesis is strongly influenced by culture medium composition. In this study, cheese whey was evaluated as an alternative fermentation substrate for kefiran production, and the effect of supplementation with fermentable sugars (glucose, galactose, and lactose) and casein was assessed under controlled conditions. Kefir grains were cultivated in whey- and milk-based media, and kefiran production was quantified using an anthrone-based method, while grain growth and carbohydrate consumption were monitored. Supplementation with sugars and casein reduced kefiran production by up to 34.6% and did not improve yield, whereas unsupplemented whey supported the highest kefiran concentration (86.9 ± 3.7 mg/L), comparable to that obtained in semi-skimmed milk (84.0 ± 3.0 mg/L). The recovered polysaccharide was characterized by Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹H NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), showing structural and physicochemical properties comparable to kefiran obtained from semi-skimmed milk. These results indicate that whey constitutes a feasible and simple fermentation medium for kefiran production, and that increased medium complexity does not necessarily improve process performance. Full article

This study was aimed at producing galactooligosaccharides (GOS) from Porungo cheese whey in immobilized enzyme bioreactors. The β-galactosidase was produced, concentrated, and immobilized on chitosan–genipin supports. Initially, GOS production was conducted in conical flasks, investigating three different variables: enzyme concentration (50–150 U/mL), Porungo cheese whey concentration (200–400 g/L), and temperature (37–43 °C). The highest GOS yields (15.24%) occurred under intermediate process conditions (100 U/mL, 300 g/L, 40 °C), reaching a GOS concentration of 27.04 g/L. These conditions were then used in a packed-bed column bioreactor operated in batch mode, achieving yields of 19.72%. Repeated batches were carried out, and the system was stable until the fifth cycle, with enzyme activity remaining at 83.56% of the initial level. Continuous bioreactors were conducted, varying feed flow rates (1–3 mL/h), with the highest yields and lactose conversion occurring for the longest residence time (24.63% and 68.38%), respectively, with high GOS concentration (44.14 g/L). Microorganisms isolated from Porungo cheese showed the ability to metabolize the GOS produced, demonstrating its prebiotic potential. This work can contribute to optimizing the production of GOS, an important product for pharmaceuticals and food industries. Full article

The integrated valorization of whey into multifunctional food ingredients is constrained by sequential processing routes and the need for purified lactose and protein fractions. The simultaneous enzymatic conversion of lactose and whey proteins in a single reactor remains underexplored despite the frequent co-formulation of galacto-oligosaccharides (GOS) and whey protein hydrolysates in functional foods. This study evaluated the feasibility of a one-pot enzymatic system using native whey as the sole substrate for the concurrent production of GOS and antioxidant peptide fractions. A batch process combining β-galactosidase from Aspergillus oryzae and Alcalase^® was assessed through a 3² factorial design, analyzing the effects of pH (4.5–6.5) and temperature (40–60 °C) on GOS yield and degree of protein hydrolysis. The system enabled simultaneous transgalactosylation and proteolysis under mildly acidic conditions without significant mutual enzyme inhibition. Multi-response optimization identified pH 6.0 and 59.5 °C as the optimal conditions, yielding 25.7 ± 0.2% GOSs and 10.5 ± 0.3% protein hydrolysis. The antioxidant capacity and emulsifying and foaming properties were strongly dependent on pH, temperature, and reaction time. The results demonstrate that native whey can be directly transformed into a multifunctional ingredient through a one-pot enzymatic strategy, offering a simplified valorization approach. Full article

The aim of the circular economy for plastics is to replace some of them with bio-based polymers in the future. In this work, second cheese whey (SCW) was used as a low-cost substrate for the production of the natural polyester poly(3-hydroxybutyrate)-hydroxybutyrate (PHB) by three Pseudomonas sp. phDV1 strains, namely, the wild type, a depolymerase PhaZ and PhaR knockout mutants. SCW has high polluting loads, characterized by high levels of lactose, phosphorus, nitrogen and salinity, as well as high turbidity due to the presence of whey solids. Initially, SCW was evaluated as the sole carbon source for the growth of the bacterial strains and the production of PHB. Fermentation conditions were screened to maximize polymer synthesis. Small-scale experiments showed that the strains could grow and produce PHB in SCW with and without enzymatic treatment. The formation and intracellular localization of PHB were determined with fluorescence microscopy, using Nile Red staining. Analytical HPLC was also used to quantify the PHB content in the cells and to optimize production. This study demonstrates the efficacy of Pseudomonas sp. phDV1 in SCW treatment and biomass valorization, providing a sustainable solution for dairy wastewater management while producing valuable resources. Full article

In whey valorization, membrane separation stands out as a highly effective technique for purifying and isolating the various components of whey. The efficiency of whey ultrafiltration and diafiltration (UF/DF) largely depends on the balance between membrane selectivity, hydrodynamic conditions, and solute interactions at the membrane interface. In this study, sweet whey was fractioned using 10, 30 and 50 kDa polyether sulfone (PES) membranes under identical transmembrane pressure (TMP = 2.5 bar) with ultrafiltration and a subsequent 4-step constant volume diafiltration stages. The resulting compositional and dielectric changes were evaluated to identify optimal separation conditions and assess the applicability of dielectric parameter measurement as a rapid, non-destructive monitoring technique. Results showed that, regardless of the applied molecular weight cut-off (MWCO), using three DF cycles can wash out almost all the removable lactose from the retentates, and the dielectric assessment of both permeate and retentate fractions showed a strong, linear relationship between the change in dielectric behavior and the composition of each fraction. Analysis of the dielectric spectra confirmed that the ratio of the dielectric constant to the loss factor (ε′/ε″) exhibited a strong linear correlation (R² > 0.98, r > 0.99) with lactose concentration in the permeate fractions of all three MWCO membranes, as well as a similarly strong correlation (R² > 0.975, r > 0.98) with the total chemical oxygen demand (TCOD) measured in the retentate fractions. Full article

Whey, a by-product of cheese and casein manufacture, represents a major output in dairy processing and a valuable resource for the production of functional foods. This review examines the technological, environmental, and nutritional aspects of whey valorization, emphasizing its transformation from an ecological burden to a raw material with high economic potential. Over time, whey has evolved from being regarded as waste product to becoming a strategic ingredient in the formulation of modern functional foods and bio-based materials. Data from January 2015 to October 2025 were collected from PubMed, Web of Science, and Scopus to outline global whey production, utilization rates, and emerging processing methods. Modern membrane, enzymatic, and non-thermal technologies enable the recovery of valuable components, including proteins, lactose, and bioactive compounds. The use of these techniques reduces the biochemical and chemical oxygen demand in wastewater The review highlights the use of whey in functional beverages, milk and meat processing, edible films, bioplastics, and biofuels, as well as its microbiological and biotechnological potential. Results indicate that only about half of the 180–200 million tonnes of whey produced annually is effectively valorized, underscoring the need for integrated circular-economy approaches. Overall, whey valorization contributes to sustainable food production, environmental protection, and the development of innovative, health-promoting products that align with global strategies for waste reduction and the development of functional foods. Full article

Background/Objectives: Metabolites are low-molecular-weight organic compounds (<1 kDa) that act as intermediates and end products of cellular metabolism. Their characterization provides valuable information on the nutritional quality, functionality, and potential health impacts of food products. In the dairy sector, proton nuclear magnetic resonance (¹H NMR) spectroscopy has emerged as a powerful tool for metabolite profiling, enabling the simultaneous identification and quantification of diverse compounds. In this study, ¹H NMR was applied to characterize and compare the metabolic composition of whey, a major by-product of cheese and yogurt production, and whey protein concentrate (WPC-80), a whey derivative containing approximately 80% protein by weight and rich in essential amino acids. Methods: Five whey and four WPC-80 samples from a single Parmigiano Reggiano dairy plant were collected, each representing a biologically independent sample. Statistical evaluation was performed using Mann–Whitney U tests to identify significantly different metabolites between groups, while principal component analysis and partial least squares discriminant analysis were employed to assess group separation and determine discriminant metabolites. Results: The results revealed marked compositional differences: whey was higher in dimethyl sulfone, succinate, orotate, fumarate, and lactose (p < 0.05), whereas WPC-80 contained significantly higher levels of histidine, formate, glucose + glucose-6-phosphate, acetate, and choline (p < 0.05). Moreover, metabolites such as hippurate, valine, lactate + threonine, and uracil were exclusively found on whey and not in WPC-80, likely due to processing steps such as ultrafiltration. Conclusions: These findings highlight the metabolic distinctions introduced by WPC-80 processing from Parmigiano Reggiano whey and provide insights into the nutritional and functional characteristics of whey-derived products. Such knowledge can inform the design of innovative dairy ingredients and functional foods, with potential benefits for both industry applications and consumer health. Full article

Microbial bioconversion of agro-industrial by-products into high-value-added metabolites such as polysaccharides or lipids serves a dual purpose: mitigating environmental pollution through waste reduction and supporting the development of novel bioproducts. In this study, a non-conventional, poorly studied Cryptococcus albidus strain was initially assessed for its ability to grow on semi-defined media containing lactose, glycerol, or glucose under three distinct nitrogen availability conditions at C/N equal to 20, 80, and 160 mol/mol in shake flask cultures. The goal was to evaluate biomass production and synthesis of valuable metabolites under these conditions. C. albidus demonstrated robust growth on all commercial carbon sources, particularly under nitrogen-rich conditions, producing more than 25.0 g/L of microbial biomass with a high intracellular polysaccharide content (>45%, w/w). Additionally, mannitol production was detected in cultures with glycerol and glucose (9.1 and 13.1 g/L, respectively), especially after nitrogen depletion. Subsequently, C. albidus and a Cutaneotrichosporon curvatus strain were batch-cultivated using pretreated secondary cheese whey (SCW) as a carbon-rich waste substrate. When cultivated on SCW, both yeast strains partially metabolized lactose and produced polysaccharide-rich biomass, dominated by β-glucans (>29% of total biomass), compounds known for their functional and bioactive properties. The cellular polysaccharides (cPS extracted from C. albidus exhibited cytotoxic effects against cancer cells, suggesting their potential use as biological response modifiers. In contrast, the cPS from C. curvatus did not affect cell viability, indicating their promise as ingredients for applications in the food, feed, pharmaceutical, or cosmetic sectors. Full article

The use of lactose-utilizing microalgae offers a sustainable and cost-effective approach for the bioconversion of dairy industry side-streams and the reduction in microalgae production costs. This work aims to improve the biomass productivity of the lactose-utilizing microalgal strain Graesiella emersonii MSCL 1718 in concentrated cheese whey permeate. It was demonstrated that the mixotrophic growth of the axenic G. emersonii culture resulted in a significantly higher biomass productivity in 20% permeate medium compared to the heterotrophic cultivation. Furthermore, supplementation of the permeate medium with iron, zinc, cobalt, and molybdenum resulted in 12.8%, 12.9%, 9.3%, and 28.9% significant increases (p < 0.05) in biomass synthesis, respectively, compared to the control permeate group. In the subsequent experiment, G. emersonii cultivated in molybdenum-supplemented permeate resulted in 0.34 ± 0.02 g/(L·d) biomass productivity and twofold higher lipid content (30.21 ± 1.29%) compared to the photoautotrophic control in defined synthetic medium. Analysis of the fatty acid composition revealed a twofold increase in saturated fatty acids, reaching 62.16% under mixotrophic cultivation in permeate, compared with the photoautotrophic control. Overall, concentrated cheese permeate proved to be a suitable medium for G. emersonii biomass production, supporting both enhanced growth and increased lipid accumulation. Full article

Lactic acid bacteria (LAB) play a crucial role in acid-curd cheese production by driving milk protein coagulation and forming metabolites that determine texture, safety, and flavor. This study investigated the effect of enzymatic lactose hydrolysis using β-D-galactosidase (Maxilact LX5000) on the quality of full-fat curd cheeses (16.5% and 20.8% dry matter) produced without whey separation. Cheeses were manufactured with or without prior lactose hydrolysis, inoculated with a mesophilic Flora Danica starter culture, and stored for 28 days at 4 °C. Chemical composition, sugar profile (HPLC), pH, LAB viability, textural properties (hardness, adhesiveness, and water-holding capacity), and sensory attributes were determined. Lactose hydrolysis completely eliminated lactose and increased glucose and galactose concentrations, without significant changes in protein, fat, or pH level. In our data, lactose was undetectable in hydrolyzed samples across storage, glucose/galactose exhibited only minor fluctuations, and LAB counts and pH remained stable, indicating a largely stable sugar profile and limited microbial activity under refrigeration. Hydrolyzed samples showed improved texture, especially higher hardness and moisture retention in low-dry-matter variants, while sensory characteristics were comparable to the control and free from excessive sweetness. These results demonstrate that enzymatic lactose hydrolysis is an effective tool for producing lactose-free curd cheese without compromising quality. This process can be recommended for sustainable whey-free cheese manufacture aimed at lactose-intolerant consumers. Full article