Search Results (23)

Second cheese whey (SCW), a major by-product of ricotta cheese production, poses significant environmental challenges due to its high organic load. Biohydrogen (bio-H₂) and poly-β-hydroxybutyrate (PHB) production offer a sustainable reuse of SCW, that provides ideal nutrients for microbial growth. This study aimed to convert SCW into Bio-H₂ and PHB using a 5-liter tubular bioreactor in a sequential lactic fermentation and photofermentation system. Two lighting conditions were tested: white LED (WL) and selected LED (SL). Optimal results were achieved with a co-inoculum of Lactococcus lactis MK L84 and Lacticaseibacillus paracasei MK L49 at pH 4.5–5.5, followed by photofermentation with Rhodopseudomonas palustris 42OL under SL condition. The process yielded an average of 0.47 L of H₂ per liter of substrate and 1.66% wPHB/wCDW. This approach successfully transformed dairy waste into high-value products, promoting circular economy principles. Full article

Ricotta cheese whey (RCW) is a by-product with nutritional potential, but its use in the human diet is limited due to its high salinity. Chlorella vulgaris can use RCW as a substrate to enhance biomass productivity. The aim of this work was to evaluate different conditions for C. vulgaris growth in RCW, during scaling-up analysis. After preliminary assays to select growth conditions, two systems were prepared as follows: 500 mL Erlenmeyer flasks (control-system) and a 3 L Bioreactor. Microfiltrated RCW was used as a substrate for C. vulgaris LPMA39 production. Biomass was measured and productivity at 96 h, cell growth kinetics behaviour, biomass biochemical characterisation, and the efficiency of nutrient removal were determined. Both systems presented the same biomass concentration at 96 h (2.2–2.8 g·L⁻¹) and productivity (0.021–0.027 g·L⁻¹·h⁻¹). Nevertheless, 11 h lag-period for cell adaptation to the 3 L Bioreactor was required; thereafter, cells grew faster (µ_max: 0.32 ± 0.08 h⁻¹) than control-system. Finally, slight but significantly lower C_max: 2.14 ± 0.08 was obtained when comparing it to control-system. Lipids, proteins, and pigment contents decreased by the scaling-up; meanwhile, higher reduction in chemical oxygen demand (COD), total phosphorus, and total nitrogen were recorded in the 3 L Bioreactor. Identifying the operating conditions that improve C. vulgaris performance in non-diluted RCW remains a challenge from a sustainability standpoint. Full article

Sialic acids (SIAs) are bioactive compounds present in glycoproteins and glycolipids, playing key roles in human physiology. N-acetylneuraminic acid (Neu5Ac), the only sialic acid synthesized by humans, contributes to neurodevelopment and immune function, whereas N-glycolylneuraminic acid (Neu5Gc), acquired from animal-derived foods, is potentially harmful, showing pro-inflammatory properties. Accordingly, a high Neu5Ac/Neu5Gc ratio represents an important nutritional indicator. This study quantified the two main forms of SIA in five commercial cheese types (mozzarella, stracchino, caciotta, robiola, ricotta) produced from cow (C), buffalo (B), and goat (G) milk, as well as in laboratory cheesemaking from 1000 g of milk from each species. Neu5Gc concentrations were significantly higher in G cheeses (p < 0.001), while Neu5Ac was more abundant in C cheeses (p < 0.05). Consequently, the Neu5Ac/Neu5Gc ratio was markedly higher in C and B cheeses (24.11 and 21.57, respectively) than in G (1.29), reflecting species-specific glycosylation patterns. Among cheese types, ricotta produced from whey exhibited the highest SIA concentrations among all species, followed by robiola, mozzarella and stracchino. In contrast, caciotta showed the lowest SIA levels. The laboratory cheesemaking trial confirmed that most SIAs remained bound to whey proteins. These findings highlighted the combined effect of milk species and cheesemaking on sialylation, with potential nutritional implications. Full article

The dairy sector produces considerable amounts of nutrient-rich effluents, which are frequently undervalued as simple by-products or waste. In particular, Second Cheese Whey (SCW), also known as scotta, exhausted whey, or deproteinized whey, represents the liquid fraction from ricotta cheese production. Despite its abundance and high organic and saline content, SCW is often improperly discharged into terrestrial and aquatic ecosystems, causing both environmental impact and resource waste. The available purification methods are expensive for dairy companies, and, at best, SCW is reused as feed or fertilizer. In recent years, increasing awareness of sustainability and circular economy principles has increased interest in the valorization of SCW. Biological treatment of SCW using microalgae represents an attractive strategy, as it simultaneously reduces the organic load and converts waste into algal biomass. This biomass can be further valorized as a source of proteins, pigments, and bioactive compounds with industrial relevance, supporting applications in food, nutraceuticals, biofuels, and cosmetics. This review, starting from analyzing the characteristics, production volumes, and environmental issues associated with SCW, focused on the potential of microalgae application for their valorization. In addition, the broader regulatory and sustainability aspects related to biomass utilization and treated SCW are considered, highlighting both the promises and limitations of microalgae-based strategies by integrating technological prospects with policy considerations. Full article

This study aimed to evaluate the effect of using artisanal beers obtained from ricotta whey (scotta-based beer) during cheese affinage on the sensory properties of cheeses. For this purpose, four experimental groups of pressed cheeses were manufactured using two ripening techniques and a scotta-based brine. In detail, BB stands for experimental cheeses immersed in unsaturated beer brine; CB represents control cheeses immersed in unsaturated water brine; BWR corresponds to experimental cheeses with a washed rind using beer brine; and CWR denotes control cheeses with a washed rind using saturated water brine. The replacement of water with scotta-based beer in unsaturated brine, during cheese affinage, resulted in significant changes in the VOC profile of experimental cheeses, compared to control cheeses, with esters accounting for more than 60% of the total VOC area, imparting sweet and fruity notes. Sensory analysis revealed that beer-brined cheeses exhibited significantly different profiles (p < 0.05) across most evaluated attributes. Notably, the color of the rind and interior, as well as visual uniformity, were significantly enhanced by the beer brining, while oiliness was influenced by the ripening technique (p < 0.05) independently of the brine composition. Odor intensity and aroma complexity were markedly higher in beer-brined cheeses (p < 0.001), consistent with the migration of volatile compounds from beer into the cheese matrix. Among taste attributes, sourness, bitterness, and toasted flavor differed significantly (p < 0.05), with beer-brined cheeses perceived as less sour and more toasted. Washed-rind cheeses exhibited higher bitterness (p < 0.001), regardless of brining type. Furthermore, beer-brined cheeses showed increased hardness and plasticity, suggesting structural changes in the matrix. These findings support the potential of scotta-based beer-brining as a way to diversify cheese sensory profiles and enhance market value. Full article

Valorization of ricotta cheese exhausted whey (RCEW), a dairy by-product generated in large quantities worldwide, is essential to mitigate its environmental impact and unlock its economic potential. This study explores the use of RCEW as a substrate for polyhydroxyalkanoate (PHA) production by Azohydromonas lata DSM 1123. The substrate was characterized by low protein and fat contents and a relevant lactose concentration (3.81%, w/v). Due to A. lata’s inability to directly metabolize lactose, β-galactosidase supplementation was necessary. Mineral supplementation of pasteurized RCEW significantly improved both microbial biomass and PHA synthesis, achieving up to 25.94% intracellular PHA content, whereas pre-adaptation trials failed to enhance strain performance. Moderate nitrogen limitation in the substrate (C/N ratio 44) favored PHA synthesis (0.55 g/L) and 32.74% intracellular accumulation. Thermal treatments decreased initial microbial contamination, hence a balanced mixture of pasteurized–sterilized (75:25) substrate was used to modulate RCEW protein content without the inclusion of additional technological or chemical processing steps and without lactose loss or dilution. Bioreactor trials using optimized RCEW pre-treatment conditions led to a further increase in biomass (2.36 g/L) and PHA production (0.88 g/L), especially under fed-batch conditions. The extracted polymer was confirmed to be polyhydroxybutyrate (PHB), with high thermal stability and a molecular weight of 5.9 KDa. Full article

Buffalo mozzarella cheese whey (CW) and ricotta cheese exhausted whey (RCEW) are valuable by-products of the Mozzarella di Bufala Campana PDO production chain. This study characterized their microbial communities using an integrated culture-dependent and -independent approach. Metabarcoding analysis revealed that the dominance of lactic acid bacteria (LAB), including Streptococcus thermophilus, Lactobacillus delbrueckii, and Lactobacillus helveticus, alongside diverse heat-resistant yeasts such as Cyberlindnera jadinii. Culture-based isolation identified subdominant lactic acid bacteria strains, not detected by sequencing, belonging to Leuconostoc mesenteroides, Enterococcus faecalis, and Enterococcus durans. These strains were further assessed for their probiotic potential. E. faecalis CW1 and E. durans RCEW2 showed tolerance to acidic pH, bile salts, and lysozyme, as well as a strong biofilm-forming capacity and antimicrobial activity against Bacillus cereus and Staphylococcus aureus. Moreover, bile salt resistance suggests potential functionality in cholesterol metabolism. These findings support the potential use of CW and RCEW as reservoirs of novel, autochthonous probiotic strains and underscore the value of regional dairy by-products in food biotechnology and gut health applications. Full article

Whey cheeses have been produced from the very early steps of cheesemaking practices as a sustainable way to utilize whey, which is the main by-product of cheesemaking. Traditional whey cheeses, manufactured with similar processes, are Ricotta, Ricotta salata or Ricottone, and Ricotta fresca in Italy; Anthotyros, Myzithra, Manouri, Xynomyzithra, and Urda in Greece; Urda in Serbia and Romania as well as in other countries such as Israel; Lor in Turkey; Anari in Cyprus; Skuta in Croatia and Serbia; Gjetost and Brunost in Norway; Mesost and Messmör in Sweden; Mysuostur in Iceland; Myseost in Denmark; Requeijão in Portugal; and Requesón in Spain and Mexico. The production of whey cheese is based on the denaturation of whey proteins by heating to 88–92 °C. The specific processing conditions and aspects of the microbiology of whey cheeses are discussed. The special characteristics of whey cheeses, which are high pH and high moisture content, make them susceptible to microbial growth. Due to the limited shelf life of these products, extended research has been carried out to extend the shelf life of whey cheese. The sustainable preservation approaches, such as modified atmosphere packaging, addition of herbs and/or plant extracts, and bio-preservation methods are reviewed. Moreover, novel whey cheeses focused on functional properties have developed during the last 10 years. Full article

Cheese whey management and disposal is a major issue for dairy industries due to its high level of chemical and biochemical oxygen demand. However, it can still represent a source of nutrients (i.e., sugars, proteins and lipids) that can be applied, among other options, as substrate for microbial growth. Yarrowia lipolytica can grow in different environments, consuming both hydrophilic and hydrophobic substrates, and tolerates high salt concentrations. In this work, the lipolytic and proteolytic profile of 20 strains of Y. lipolytica were tested on caseins and butter. Then, their growth potential was evaluated in four types of whey (caciotta, ricotta, squacquerone and their mix). Y. lipolytica showed a very strain-dependent behavior for both hydrolytic profiles and growth capabilities on the different substrates. The best growers for all the types of whey tested were PO1, PO2, and RO2, with the first one reaching up to 8.77 log cfu/mL in caciotta whey after 72 h. The volatile molecule profile of the samples incubated with the best growers were characterized by higher amounts of esters, acids, ketones and alcohols. In this way, cheese whey can become a source of microbial cultures exploitable in the dairy sector. Full article

The fatty acid (FA) profiles of 240 samples of ricotta whey cheese made from sheep, goat, cow, or water buffalo milk were analyzed by gas-chromatography (GC). Then, sequential preprocessing through orthogonalization (SPORT) was used in order to classify samples according to the nature of the milk they were made from. This strategy achieved excellent results, correctly classifying 77 (out of 80) validation samples. Eventually, since 36 (over 114) sheep ricotta whey cheeses were PDO products, a second classification problem, finalizing the discrimination of PDO and Non-PDO dairies, was faced. In this case, two classifiers were used, SPORT and soft independent modelling by class analogy (SIMCA). Both approaches provided more than satisfying results; in fact, SPORT properly assigned 63 (of 65) test samples, whereas the SIMCA model accepted 14 PDO individuals over 15 (93.3% sensitivity) and correctly rejected all the other samples (100.0% specificity). In conclusion, all the tested approaches resulted as suitable for the two fixed purposes. Eventually, variable importance in projection (VIP) analysis was used to understand which FAs characterize the different categories of ricotta. Among the 22 analyzed compounds, about 10 are considered the most relevant for the solution of the investigated problems. Full article

This study aimed to analyze the population dynamics of methanogenic archaea in co-digestion systems operated under different concentrations of industrial waste such as ricotta whey and brewery waste sludge in association with bovine manure. It was believed that the association of these residues from the food industry combined with bovine manure can contribute to improve the production of biogas. To identify the archaea, DNA extractions and the sequencing of the 16s rRNA gene were performed from 38 samples of influents and effluents. The results indicated that Methanosaeta and Methanosarcina were predominant in the co-digestion of ricotta cheese whey and that Methanosaeta, Methanocorpusculum, and Methanobrevibacter prevailed in the co-digestion of residual brewery sludge. The three ricotta cheese whey biodigesters demonstrated efficiency in methane production; in contrast, residual sludge of brewery biodigesters only showed efficiency in the system operated with 20% co-substrate. Full article

Aiming at valorizing the ricotta cheese exhausted whey (RCEW), one of the most abundant by-products from the dairy industry, a biotechnological protocol to obtain bioactive peptides with angiotensin-I-converting enzyme (ACE)—inhibitory activity was set up. The approach was based on the combination of membrane filtration and fermentation. A Lactobacillus helveticus strain selected to be used as starter for the fermentation of the ultrafiltration protein-rich retentate (R-UF) obtained from RCEW. The fermented R-UF was characterized by a high anti-ACE activity. Peptides responsible for the bioactivity were purified and identified through nano-LC–ESI–MS/MS. The sequences identified in the purified active fractions of the fermented R-UF showed partial or complete overlapping with previously reported κ-casein antihypertensive fragments. The fermented R-UF was spray-dried and used to enrich ricotta cheese at different fortification level (1 and 5% w/w). An integrated approach including the assessment of the microbiological, chemical, functional, textural, and sensory properties was used to characterize the fortified products. A significantly higher anti-ACE activity was found in the ricotta cheese fortified with fermented R-UF as compared to the control and to the samples obtained with the unfermented R-UF fraction at the same levels of fortification. In particular, a 100 g portion of the ricotta cheese produced at 5% fortification level contained circa 30 mg of bioactive peptides. The fortification led to a moderate acidification, increased hardness and chewiness, and decreased the milk odor and taste of the ricotta cheese as compared to the control, while flavor persistence and sapidity improved. Full article

During Pecorino Romano PDO cheese production, scotta (residual whey from ricotta cheese manufacturing) or siero (whey) can be integrated with autochthonous starters, natural and composed of an indefinite number of species and strains, or commercial selected starters to obtain scotta/siero-innesto. In this study, three biodiverse autochthonous natural starter cultures (SR30, SR56, and SR63) belonging to the Agris Sardegna BNSS microbial collection, composed of different strains belonging to the species Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Enterococcus faecium, and Limosilactobacillus reuteri were lyophilized and combined into two starter mixes (A and B). The scotta/siero-innesto and the Pecorino Romano obtained using natural starters were compared with those obtained using commercial selected starters during three seasons of the cheesemaking campaign. Different pH and microbial compositions for the scotta/siero-innesto obtained using natural or commercial starters were found, attributable to their different biodiversity. The six-month-ripened cheese microbiota was influenced mostly by the season of cheesemaking, whereas physico-chemical and sensory analyses did not highlight differences among the products obtained. In general, no effect attributable to the type of scotta/siero-innesto used was observed, allowing the conclusion that natural starter cultures can be used also in industrial-scale production, ensuring high stability in the technological performances and preserving the microbial, chemical, and sensory characteristics of Pecorino Romano PDO cheese. Full article

Novel strategies for wheys application, decreasing its negative environmental impact, represent a challenge for dairy industries. The use of wheys as replacers may lead to adverse sensory quality changes in conventional dairy products. This study aimed to investigate the sensory effects of the use of ricotta whey (RW), cheese whey (CW), and butter whey (BW) in replacement to whole milk (WM) at different ratios (0:100%, 25:75%, 50:50%, 75:25%, and 100:0%, w/w) in chocolate ice creams. All formulations, including a commercial sample used as a reference, were analyzed for overall liking, purchase intention, just-about-right (JAR), and survival analysis. RW, CW, and BW up to 75%, 100%, and 25% did not affect (p > 0.05) the overall liking, respectively. Purchase intention was only decreased (p < 0.05) by BW at 50%, 75%, and 100% compared to a commercial sample. Considering data from PCA and PLSR associated with hedonic scores and penalty analysis, the main adverse sensory effects on overall liking were: increased perception (p < 0.05) of chocolate flavor by RW, CW, and BW, melting velocity by RW, sweetness by CW and BW, and chocolate aroma by BW. Survival analysis indicated that BW could be added up to a maximum of 84.15%, while no rejection was detected for RW and CW. Based on results, RW, CW, and BW represent potential milk replacers to be used by the dairy industry, decreasing the environmental impact of these dairy by-products. Full article

Lactic acid (LA) obtained by fermentation of carbohydrates is well-known and widely used in the food sector. This process is as an alternative to the chemical synthesis and ensures several advantages especially in terms of environmental sustainability. In particularly, the opportunity to use agro-food residues as fermentable raw materials could improve the overall process sustainability, without considering the indisputable advantages in terms of waste reduction and residual biomass valorization, in a bio- and circular economy perspective. This research deals with the study and development of the fermentation processes of various waste biomasses from the agro-food industries, including milk whey (MW), ricotta cheese whey (RCW), pear processing residues (PPR), potato pomace (PP), tomato pomace (PT), in order to obtain an experimental protocol applicable to the production of LA. Lactobacillus casei DSM 20011 (ATCC 393), a homofermentative L(+)-LA producing bacterium has been used, starting from small-scale tests to verify of the microorganism to grow in complex medium with different carbon sources and the possible presence of potentially toxic substances for microbial growth. Yields from 27.0 ± 0.3% to 46.0 ± 0.7% have been obtained. Then, a scaling-up was performed in a 1 L batch fermenter, using a mixed medium of RCW and PPR in different ratio. The best LA yield was 78.3% with a volumetric productivity of 1.12 g/L·h in less than 60 h. Full article