Search Results (48)

Consumer interest in vegetarian, ethical, and clean-label foods is reviving the use of plant-derived milk coagulants. Cardosins from Cynara cardunculus (“thistle”) are aspartic proteases with strong clotting activity, yet their technological impact in cheese remains under-explored. This study compared a commercial thistle extract (PC) with traditional bovine rennet rich in chymosin (AC) during manufacture and 60-day ripening of Caciotta cheese. Classical compositional assays (ripening index, texture profile, color, solubility) were integrated with scanning electron microscopy, three-dimensional surface reconstruction, and descriptive sensory analysis. AC cheeses displayed slower but sustained proteolysis, yielding a higher and more linear ripening index, softer body, greater solubility, and brighter, more yellow appearance. Imaging revealed a continuous protein matrix with uniformly distributed, larger pores, consistent with a dairy-like sensory profile dominated by milky and umami notes. Conversely, PC cheeses underwent rapid early proteolysis that plateaued, producing firmer, chewier curds with lower solubility and darker color. Micrographs showed a fragmented matrix with smaller, heterogeneous pores; sensory evaluation highlighted vegetal, bitter, and astringent attributes. The data demonstrate that thistle coagulant can successfully replace animal rennet but generates cheeses with distinct structural and sensory fingerprints. The optimization of process parameters is therefore required when targeting specific product styles. Full article

In dairy cattle, abomasal ulcers are a serious but sometimes disregarded ailment that can have detrimental effects on health and cause financial losses. Due to inconclusive clinical symptoms, abomasal ulcers are typically misdiagnosed and treated improperly. Specialized diagnostic methods should be considered to ensure a correct diagnosis and the well-being of cattle. This report focuses on a 4-year-old Holstein-Friesian cow which began her third lactation two weeks before she started showing general clinical signs of an elevated fat–protein ratio in the milk and was diagnosed with an abomasum displacement. The clinical signs can also be mistaken for other conditions such as traumatic reticuloperitonitis and left dislocated abomasum. The patient was brought to the LUHS Large Animal Clinic, and after a short while, sudden death occurred. The autopsy concluded that death had occurred due to hypovolemic shock caused by abomasal ulcer perforation, which caused bleeding into the abomasum and intestines. Also, the type 3 ulcer caused severe peritonitis and anemia, and feed and fibrin could be seen on the outside of organs in the abdomen. Blood clots mixed with feed had formed in the inside of the abomasum and intestinal tract. Based on the work of previous scientific studies, it has been established that the occurrence of ulcers is more frequent in dairy cows during the first four to six weeks of lactation. And the most probable cause could be intensive feeding and dietary changes. Ulcers in the abomasum are very difficult to diagnose, because they require special diagnostic equipment such as an ultrasound or surgical interventions. Due to the similarity with other diseases, this pathological condition of the abomasum is most frequently only identified in post-mortem examinations. Full article

This study demonstrates that Bacillus subtilis GDAAS-A32-derived postbiotics (BSP) enhance yogurt production by optimizing lactic acid bacteria (LAB) viability and functionality. BSP enhanced the growth kinetics and biomass accumulation of Streptococcus thermophilus and Lactobacillus bulgaricus in both an anaerobic and aerobic pure system. The addition of BSP significantly increased the viable cell counts of S. thermophilus and L. bulgaricus, milk-clotting activity, sensory properties, and extracellular polysaccharide content and improved the rheological properties. Moreover, BSP elevated viable counts of S. thermophilus and L. bulgaricus to 6.18 × 10⁸ CFU/g and 1.03 × 10⁸ CFU/g, respectively, by day 7—representing 11.3-fold and 9.3-fold increases versus controls at 20% supplementation. Metabolomic signatures confirmed peptidoglycan reinforcement and flavor enhancement. Mechanistically, BSP supplementation might reduce urate and H₂O₂ toxicity through NH₃-mediated proton neutralization and oxygen scavenging, while establishing a pyrimidine salvage network and redirecting one-carbon metabolism, resulting in enhanced stress tolerance and significant improvements in bacterial viability. Full article

The process of camel milk’s transformation into cheese is a delicate operation due to various difficulties in achieving coagulation. This study investigates the processing challenges of camel milk in the production of camel milk cheese using chicken gizzard inner lining extract (CGLE) as a coagulant. The crude extract presents an extraction yield of 55.05 ± 1.8% and a pH = 4.40 ± 0.05. The optimal coagulation conditions were pH 5 and temperature 45 °C. A fresh camel milk cheese was produced using CGLE and characterized as CME. The cheese yield of the CME was 26.88 ± 0.42%, which was higher than that obtained with chymosin (CC) at 12.66 ± 0.12%. The pH and acidity were 5.29 ± 0.09 and 56.25 ± 1.25°D. The gross composition of camel cheese (CME) was determined in comparison to (CC) fat (13.50 ± 2.82%), proteins (11.61 ± 0.19%), and dry matter (38.85 ± 1.22%). The sensory analysis demonstrated significant differences (p < 0.05) between the CME and CC in terms of white color, acidic taste, and consistency. Therefore, CME presents an overall acceptability in comparison to the control. The chicken gizzard inner lining extract could be used as an efficient coagulant for the production of fresh camel cheese. Full article

Milk coagulants play a crucial role in defining curd characteristics. The objective of this study was to compare the coagulation dynamics of two commonly used coagulants in cheesemaking: cardoon flower extract (Cynara cardunculus L.) and commercial chymosin, using sheep milk from four different origins in the Baixo Alentejo region of Portugal, as the substrate. Milk composition was determined using the MilkoScan 133B, while the milk-clotting time (MCT) was measured following ISO 23058/IDF 199:2006 guidelines with slight modifications and coagulation kinetics, and technological properties were evaluated using the Optigraph apparatus. The results demonstrate that the type of coagulant impacts the coagulation properties of sheep milk. Pearson’s correlation analysis indicated that milk samples with higher protein content exhibited longer coagulation times but resulted in firmer curds. On the other hand, the use of cardoon flower extract introduced greater variability compared to chymosin, with a delayed onset of coagulation, reduced curd firmness, and increased variability in enzymatic kinetics. These results suggest that cardoon extract, while traditional, introduces greater heterogeneity in curd formation compared to the more consistent action of chymosin. Full article

This study explores the extraction and characterization of proteolytic enzymes from brewer’s spent grain (BSG) and their potential as sustainable coagulants in the dairy industry. BSG samples from various beer types (Blonde Ale, IPA, Kölsch, Honey, and Porter) were obtained from two artisanal breweries in Mar del Plata, Argentina. Optimization of caseinolytic activity (CA) and protein extraction was conducted using a Plackett–Burman design, followed by a Box–Behnken design. Optimal protein concentration was achieved at intermediate pH and high temperature, while CA peaked at pH 8.0. The specific caseinolytic activity (SCA) varied among the extracts, with BSG3 showing the highest activity (99.6 U mg⁻¹) and BSG1 the lowest (60.4 U mg⁻¹). Protease inhibitor assays suggested the presence of aspartic, serine, metallo, and cysteine proteases. BSG3 and BSG4 showed the highest hydrolysis rates for α-casein (70% and 78%). For κ-casein, BSG1, BSG2, and BSG3 demonstrated moderate activity (56.5%, 49%, and 55.8), while BSG4 and BSG5 exhibited the lowest activity. Additionally, the milk-clotting activity (MCA) of BSG extracts was comparable to plant-based coagulants like Cynara cardunculus and Ficus carica. These findings highlight the potential of BSG-derived proteases as alternative coagulants for cheese production, offering a sustainable link between the brewing and dairy industries. Full article

The objective of this study is to investigate how different factors, such as lactic acid bacteria, prebiotics (flaxseed powder, watercress seed powder, okra mucilage), and coagulation temperature influence the final quality of curd by conducting three optimization experiments and implementing a structured experimental plan. In the first phase, milk coagulation was assessed at 45 °C with various combinations of lactic acid bacteria (probiotics) and prebiotics (powdered flaxseed and watercress). In the second investigation phase, the effects of lowered probiotic and prebiotic (powdered flaxseed and watercress) concentrations were examined at the coagulation temperature of 38 °C. We investigated the concentration of lactic acid bacteria at 3 mg/mL of milk and the effects of temperature and prebiotics (okra mucilage and flaxseed powder). We observed short milk clotting time (2 s) using the optimized mixture (0.18 mg of probiotics, 1.5 mg of flaxseed powder, and 1.147 mg of watercress powder) per 10 mL of milk. It contrasts with the classical coagulation way optimized at (5.9 and 9.5 s), which were generated at optimal temperatures of 45 and 45.7 °C, respectively. Our new mixture improves the fermentation process of camembert cheese at 38 °C. This cheese had a high flavonoid content, fewer lactic bacteria and molds, a homogeneous texture, and no outer crust, and exceptional sensory attributes such as a creamy and fluid paste. These attributes suggest its potential benefits as a dairy product for individuals with cardiovascular and gastrointestinal conditions. Full article

This study aimed to compare the chemical composition of aqueous extracts from different aerial plant parts (leaves, stems, and flowers) of Onopordum nervosum ssp. platylepis growing in different regions (Sousse, Kairouan, and Nabeul) in Tunisia, as well as their antioxidant and milk-clotting properties for both spontaneously grown and cultivated plants. Results showed that phenolic composition varies significantly among ecotypes and plant organs (p < 0.05), with flowers containing the highest amounts of total phenols and flavonoids in both plant types. The flowers from Nabeul (NA) region showed the highest amounts of total phenols and higher phenolic contents compared to leaves and stems, with 44.75 mg GAE/g and 39.79 mg GAE/g in spontaneous and cultivated plants, respectively. However, flowers of spontaneously plants grown in Sousse (SO) showed the highest total flavonoid contents (11.42 mg QE/g). Additionally, the findings indicated that flowers contained higher concentrations of mono- and disaccharides than leaves and stems. The antioxidant activity showed that the radical scavenging activity of O. platylepis aqueous extracts is significantly affected by the organ and genotype (p < 0.05). NA genotype revealed the highest potency in inhibiting free radicals, with flowers having the lowest IC50s values in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) tests, registering 0.13 ± 0.02 and 0.14 ± 0.01 mg/mL, respectively. Milk-clotting activity was limited to flowers of this thistle. Moreover, SO and NA genotypes were identified as the most potent populations to coagulate milk in spontaneous and cultivated plants. The principal component analysis confirms the organ and genotype variability in this thistle, with the first two axes explaining 64.15% of the variance and highlighting a distinct flower group. The obtained results suggest that the domestication of this thistle could be useful for the conservation of biodiversity and the promotion of genotypes with potential technological properties. Full article

Agroindustrial by-products constitute an alternative source of feed livestock, and their use contributes to the sustainability of livestock systems and the circular bioeconomy. The effects of replacing cereal (0%, 40%, and 80%) with dehydrated orange pulp (DOP) in the diet of goats on the antioxidant and fatty acid (FA) contents of cheeses were evaluated. For a more suitable understanding of the role of coagulant enzymes in establishing the properties of the cheese, the effect of milk-clotting with animal and vegetable rennet was also analysed. The rennet did not substantially affect the FA or the antioxidant compounds, and the use of DOP did not affect the FA contents. However, the α-tocopherol levels, total phenolic compounds (TPC), and total antioxidant capacity (TAC) in cheeses increased as the percentage of DOP replacing cereals increased. Moreover, the high correlation obtained between the TAC and the TPC (r = 0.73) and α-tocopherol (r = 0.62) contents indicated the important role played by these compounds in improving the antioxidant capacity of the cheese. In conclusion, DOP is a suitable alternative to cereals in the diet of goats and improves the antioxidant status of the cheese produced. Full article

The transformation of milk into cheese largely depends on the technological properties of the raw material, with breed being a crucial factor that influences both the composition and coagulation properties of the milk used for cheesemaking. This study uses canonical correlation analysis to explore the relationships between physicochemical traits and coagulation properties in milk from various Spanish breeds, aiming to identify both common and breed-specific patterns that impact milk technological aptitude. A total of 832 milk samples from Manchega, Assaf, Merino de Grazalema, and Merino de Los Pedroches breeds were analyzed. The milk characteristics investigated included pH, composition (fat, protein, lactose, total solids), and coagulation properties (curd firmness—A₆₀, rennet clotting time—RCT, curd firming time—k₂₀, and individual laboratory curd yield—ILCY). The results reveal a shared correlation structure across breeds and unique covariation patterns in some breeds that deviate from the general trend. While Assaf and Merino de Los Pedroches follow the common correlation pattern, Manchega and Merino de Grazalema exhibit distinct patterns. This research underscores the need for in-depth study and suggests that the dairy industry could benefit from shifting from the traditional focus on maximizing fat and protein for higher curd yields to considering technological traits for selective breeding. Full article

This study conducted a seasonal analysis of bulk tank milk from 77 sheep farms to establish relationships between the concentration of major microbial groups and milk coagulation properties. The investigated milk traits included composition (pH, fat, casein, lactose), coagulation properties (curd firmness: A₆₀-, rennet clotting time: RCT-, curd firming time: k₂₀-, curd yield: CY-), and somatic cell score (SCS). The main microbial groups analyzed were total mesophilic bacteria (SPC), thermodurics (THERMO), psychrotrophs (PSYCHRO), Pseudomonas spp. (PSEUDO), lactic acid bacteria (LAB), catalase-negative gram-positive cocci (GPCNC), Escherichia coli (ECOLI), coliforms other than Escherichia coli (COLI), coagulase-positive staphylococci (CPS), coagulase-negative staphylococci (CNS), and spores of lactate-fermenting Clostridium (BAB). Mixed linear models were used to explore associations between coagulation properties and the aforementioned variables. Results demonstrated that incorporating microbial loads into the models improves their fit and the relative quality of the outcomes. An important seasonality is demonstrated by an increase in CY and A₆₀, along with a decrease in RCT and k₂₀ during autumn and winter, contrasting with spring and summer. BAB concentration resulted in a reduction of A₆₀ and an increase in RCT, whereas SPC concentration led to an enhancement of A₆₀ and a reduction in RCT. An increase in GPCNC concentration was associated with an increase in k₂₀ and a decrease in CY. Full article

Cheese production is an ancient practice to preserve a perishable food, such as milk, for a long time. The first step of cheese processing involves the addition of rennet, which contains the enzymes necessary for the hydrolysis and coagulation of the caseins present in milk. Typically, animal-derived rennet, such as calf rennet containing chymosin, are used as source of enzymes for cheese processing. Alternatively, microbial chymosin or recombinant chymosin is used. However, recently, plant-derived rennet such as the ones derived from thistle and bitter orange flowers and from artichoke (Cynara cardunculus var. scolymus) have also been demonstrated to be valid sources of enzymes for cheese processing. Therefore, herein, different plant and fruit extracts were tested and compared for their ability to coagulate milk caseins. In particular, beyond artichoke and cardoon (Cynara cardunculus) extracts, those from pineapple (Ananas comosus (L.) Merr.), papaya (Carica papaya L.), common fig (Ficus carica L.) milky sap, and oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm.) were investigated for their proteolytic, esterase, and milk-clotting activities. The extracts were then exploited as vegetable and fruit rennet for the experimental production of cheeses, which were examined, after 30 days of maturation, for their moisture, fat, protein, and free fatty acid (FFA) content. Interestingly, the artichoke, cardoon, and thistle mushroom extracts showed high proteolytic activity compared to calf rennet, while the level of esterase activity appeared to be similar for all the extracts. The papaya extract showed the lowest proteolytic and esterase activity. Although the pH, moisture, fat, and protein contents were very similar to those of cheese made with calf rennet, the medium- and long-chain FFAs broadly differed among produced cheeses, with variations in the lipid quality indices. Full article

In Sicilian forage systems, the introduction of native self-seeding annual legumes can be beneficial in low-input farming. Intercropping would be a valuable strategy for implementing pasture resources in Sicilian forage systems during late spring. The aim of this study was to evaluate the effects on ewes’ milk production of continuous grazing with two different mixtures (i) sulla (Sulla coronarium L.), burr medic (Medicago polymorpha L.), and chicory (Cichorium intybus L.) (SuBuCh); and (ii) barrel medic (Medicago truncatula Gaertn.), snail medic (Medicago scutellata L.), and burr medic (BuSnBa). Twenty lactating ewes were homogeneously divided into four groups of five ewes. Each group was assigned to one of four 1500 m² grazing sectors consisting of two replicates of SuBuCh and BuSnBa. Ewes fed with the SuBuCh mixture showed higher milk yield, higher protein (5.17 vs. 4.85%, p < 0.001) and casein content (4.02 vs. 3.73%, p < 0.001), lower urea content (37.70 vs. 45.38 mg dL⁻¹, p < 0.001), and better clotting parameters compared to ewes grazing on the BuSnBa mixture. Finally, ewes in the SuBuCh group showed a smaller decrease in live weight at the end of the grazing period compared to BuSnBa ewes (−2.05 vs. −3.55 kg, respectively), although the difference did not reach a significant level. These preliminary one-year results seem to highlight the promising role of SuBuCh intercrop leading to a potential quantitative/qualitative improvement in grazing resources and the productive performance of grazing ewes in a semi-arid Mediterranean environment. However, it is of note that these outcomes might undergo variations when subjected to a prolonged trial extending beyond three years. Full article

Automated milking systems (AMSs) already incorporate a variety of milk monitoring and sensing equipment, but the sensitivity, specificity, and positive predictive value of clinical mastitis (CM) detection remain low. A typical symptom of CM is the presence of clots in the milk during fore-stripping. The objective of this study was the development and evaluation of a deep learning model with image recognition capabilities, specifically a convolutional neural network (NN), capable of detecting such clots on pictures of the milk filter socks of the milking system, after the phase in which the first streams of milk have been discarded. In total, 696 pictures were taken with clots and 586 pictures without. These were randomly divided into 60/20/20 training, validation, and testing datasets, respectively, for the training and validation of the NN. A convolutional NN with residual connections was trained, and the hyperparameters were optimized based on the validation dataset using a genetic algorithm. The integrated gradients were calculated to explain the interpretation of the NN. The accuracy of the NN on the testing dataset was 100%. The integrated gradients showed that the NN identified the clots. Further field validation through integration into AMS is necessary, but the proposed deep learning method is very promising for the inline detection of CM on AMS farms. Full article

Moose (Alces alces) recombinant chymosin with a milk-clotting activity of 86 AU/mL was synthesized in the Kluyveromyces lactis expression system. After precipitation with ammonium sulfate and chromatographic purification, a sample of genetically engineered moose chymosin with a specific milk-clotting activity of 15,768 AU/mg was obtained, which was used for extensive biochemical characterization of the enzyme. The threshold of the thermal stability of moose chymosin was 55 °C; its complete inactivation occurred after heating at 60 °C. The total proteolytic activity of moose chymosin was 0.332 A₂₈₀ units. The ratio of milk-clotting and total proteolytic activities of the enzyme was 0.8. The K_m, k_cat and k_cat/K_m values of moose chymosin were 4.7 μM, 98.7 s⁻¹, and 21.1 μM⁻¹ s⁻¹, respectively. The pattern of change in the coagulation activity as a function of pH and Ca²⁺ concentration was consistent with the requirements for milk coagulants for cheese making. The optimum temperature of the enzyme was 50–55 °C. The introduction of Mg²⁺, Zn²⁺, Co²⁺, Ba²⁺, Fe²⁺, Mn²⁺, Ca²⁺, and Cu²⁺ into milk activated the coagulation ability of moose chymosin, while Ni ions on the contrary inhibited its activity. Using previously published data, we compared the biochemical properties of recombinant moose chymosin produced in bacterial (Escherichia coli) and yeast (K. lactis) producers. Full article