Journals
2015 EN
Giuseppe Massimo Vacca · Michele Pazzola · Maria Luisa Dettori
+5 more
This study investigated the modeling of curd-firming (CF) over time (CF(t)) of sheep milk. Milk samples from 1,121 Sarda ewes from 23 flocks were analyzed for coagulation properties. Lactodynamographic analyses were conducted for up to 60 min, and 240 CF individual observations from each sample were recorded. Individual sample CFt equation parameters (RCT(eq), rennet coagulation time; CF(P), asymptotic potential value of curd firmness; k(CF), curd-firming instant rate constant; and k(SR), curd syneresis instant rate constant) were estimated, and the derived traits (CF(max), the point at which CF(t) attained its maximum level, and tmax, the time at which CF(max) was attained) were calculated. The incidence of noncoagulating milk samples was 0.4%. The iterative estimation procedure applied to the individual coagulation data showed a small number of not-converged samples (4.4%), which had late coagulation and an almost linear pattern of the ascending part of the CF(t) curve that caused a high value of CF(P), a low value of k(CF), and a high value of k(SR). Converged samples were classified on the basis of their CF(t) curves into no-k(SR) (18.0%), low-k(SR) (72.6%), and high-k(SR) (4.5%). A CF(t) that was growing continuously because of the lack of the syneresis process characterized the no-k(SR) samples. The high-k(SR) samples had a much larger CFP, a smaller k(CF), and an anticipation of tmax, whereas the low-k(SR) samples had a fast k(CF) and a slower k(SR). The part of the average CF(t) curves that showed an increase was similar among the 3 different syneretic groups, whereas the part that decreased was different because of the expulsion of whey from the curd. The traditional milk coagulation properties recorded within 30 min were not able to detect any appreciable differences among the 4 groups of coagulating samples, which could lead to a large underestimation of the maximum CF of all samples (if predicted by a30), with the exception of the no-k(SR) samples. Large individual variability was found and was likely caused by the effects of the dairy system, such as flock size (on CF(max), t(max), and % ewes with no-k(SR) milk), flock within flock size (representing 11 to 43% of total variance for % ewes with no-k(SR) milk and CF(max), respectively), days in milk (on all model parameters and CF(max)), parity (on RCT(eq), k(SR), and CF(max)), daily milk yield (on RCT(eq) and CF(max)), and position of the individual pendulum that significantly affected model parameters and derived traits. In conclusion, the results showed that the modeling of coagulation, curd-firming, and syneresis is a suitable tool to achieve a deeper interpretation of the coagulation and curd-firming processes of sheep milk and also to study curd syneresis.
Journals
2015 EN
Anna Maria Perna · Immacolata Intaglietta · Amalia Simonetti
+1 more
The aim of this work was to investigate the antioxidant activity of Caciocavallo cheese made from the milk of 2 breeds, Italian Brown and Italian Holstein, and ripened for 1, 30, 60, 90, and 150 d. The antioxidant activity of cheese was measured using the 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric-reducing antioxidant power (FRAP), and thiol assays. Statistical analysis showed a significant effect of the studied factors. Italian Brown cheese had higher antioxidant activity than Italian Holstein cheese, and antioxidant activity increased during ripening of both cheeses types. Moreover, antioxidant activity varied during ripening depending on the rate of formation of soluble peptides. To date, few studies have evaluated the effect of genetic type on antioxidant capacity of the pasta filata cheeses; thus, this study forms the basis of new knowledge that could lead to the production of a pasta filata cheese with specific nutraceutical characteristics.
Journals
2015 EN
Juliano Leonel Gonçalves · Sarah Hwa In Lee · Eurico de Paula Arruda
+5 more
The objectives of the present study were to evaluate (1) the capacity of the microalga Prototheca zopfii isolated from subclinical bovine mastitis cases to form biofilms; and (2) the resistance of these isolates to sanitizing agents. Ten isolates of P. zopfii from cows with subclinical mastitis (somatic cell count>200×10(3) cells/mL), distributed in 5 dairy farms, were evaluated for their capacity to form biofilms in polystyrene microplate assays and stainless steel coupons, at 25°C and 37°C±1°C. Prototheca zopfii were isolated from milk samples via microbiological culture and analyzed by 18S rRNA gene sequencing. Biofilm formation on the coupons was observed by scanning electron microscopy. The resistance to sanitizing agents was assessed using the biofilm-forming P. zopfii isolates in stainless steel coupon assays, which were subjected to 3 sanitizers: peracetic acid, sodium hypochlorite, and iodine solution. To evaluate resistance to the sanitizers, the minimum inhibitory concentration (MIC) technique was performed using decreasing concentrations of the sanitizing agents (20, 10, 5, 2.5, 1.25, 0.625, 0.312, 0.156, 0.078, 0.039, and 0.019 g/L). After inoculating the isolates, all concentrations were evaluated at 3 distinct incubation periods (24, 48, and 72 h) to assess the effect of incubation time on the MIC. Using the polystyrene microplate assays, 1 isolate showed weak biofilm production, 5 moderate, and 4 strong, when incubated at 25°C±1. For isolates incubated at 37°C±1, 6 showed weak biofilm production and 4 moderate. All P. zopfii isolates (n=10) had the capacity to form biofilms on stainless steel coupons. The longer the incubation period of the P. zopfii isolates at different dilutions, the greater the concentrations of sanitizer needed to prevent growth of the microalgae under the tested conditions. We detected a significant effect of sanitizer and time of incubation (24, 48, and 72 h) on MIC values against P. zopfii isolates. The isolates were sensitive in vitro to peracetic acid (MIC90≥0.019 g/L), sodium hypochlorite (MIC90≥0.312 g/L), and iodine solution (MIC90≥0.625 g/L), after 24 h of incubation (where MIC90=concentration needed to inhibit 90% of isolates). Of the tested sanitizers, peracetic acid had the greatest efficiency against P. zopfii. We conclude that P. zopfii isolates are capable of biofilm production, which may contribute to their persistence in a milking and dairy environment.
Journals
2015 EN
Maria Calasso · L. Mancini · Raffaella Di Cagno
+2 more
Freeze-dried cell-free extracts (CFE) from Lactobacillus casei LC01, Weissella cibaria 1XF5, Hafnia alvei Moller ATCC 51815, and Debaryomyces hansenii LCF-558 were used as sources of enzyme activities for conditioning the ripening of ewe milk cheese. Compared with control cheese (CC), CFE did not affect the gross composition and the growth of the main microbial groups of the cheeses. As shown through urea-PAGE electrophoresis of the pH 4.6-soluble nitrogen fraction and the analysis of free AA, the secondary proteolysis of the cheeses with CFE added was markedly differed from that of the CC. Compared with CC, several enzyme activities were higher in the water-soluble extracts from cheeses made with CFE. In agreement, the levels of 49 volatile compounds significantly differentiated CC from the cheeses made with CFE. The level of some alcohols, ketones, sulfur compounds, and furans were the lowest in the CC, whereas most aldehydes were the highest. Each CFE seemed to affect a specific class of chemical compounds (e.g., the CFE from H. alvei ATCC 51815 mainly influenced the synthesis of sulfur compounds). Apart from the microbial source used, the cheeses with the addition of CFE showed higher score for acceptability than the control cheese. Cheese ripening was accelerated or conditioned using CFE as sources of tailored enzyme activities.
Journals
2015 EN
Mario Baratta · Maria Giuseppa Volpe · Daniele Nucera
+4 more
Epithelial cells are shed into milk during lactation, and although they generally reflect the cellular characteristics of terminally differentiated luminal cells, previously the detection of more primitive cells was described in human milk where a cell population of epithelial lineage was detected expressing markers typical of progenitor cells. In this investigation, we report the development of flow cytometry analysis to allow multiparametric assessment of mammary epithelial cells observed in milk. Cells collected from milk samples of 10 healthy dairy cows were directly analyzed for 6 different markers: CD45, CD49f, cytokeratin 14, cytokeratin 18, presence of nucleus, and cell viability. Milk samples were collected in 3 different periods of lactation: early lactation (EL=d 0-30), mid-lactation (ML=d 90-120), and late lactation (LL=210-250). Here we identify the differential expression of precursor or differentiated cell markers (or both) in mammary epithelial cells present in bovine milk. Myoepithelial cells, as indicated by cells staining positively for cytokeratin 14(+)/cytokeratin 18(-), were observed to increase from EL to LL with a high correlation with nuclear staining inferring potential proliferative activity. Furthermore, a significant increase in CD49f(+) and cytokeratin 14(+)/cytokeratin 18(+) positive cells was observed in LL. This assay is a sensitive approach for evaluating the variations in the frequency and features of living epithelial cells, whose reciprocal balance may be significant in understanding mammary gland cellular function throughout lactation. These observations suggest that mammary epithelial cell immunophenotypes could be investigated as biomarkers for mammary gland function in dairy cows.
Journals
2015 EN
C.C.G. Silva · M.F.P. DomingosLopes · Vanessa Magalhães
+4 more
Different studies in humans have provided evidence about the health benefits of probiotics. However, most probiotic strains do not maintain good viability in the harsh conditions of the gastrointestinal tract (GIT). In the present study, Latin-style fresh cheese produced with potential probiotic bacteria was tested to evaluate this cheese type as a food carrier for the delivery of viable microorganisms after exposure to simulated GIT conditions. The resistance of 28 lactic acid bacteria (LAB) strains and Listeria monocytogenes upon exposure to acidic conditions (pH 2.5) and bile and pancreatic enzymes (0.3% of bile salts and 0.1% of pancreatin) was evaluated in vitro. When compared with fresh cultures, fresh cheese greatly improved LAB survival to simulated GIT conditions, as no loss of viability was observed in either acidic conditions (pH 2.5) or bile salts and pancreatin environment over a 3-h period. In opposition, L. monocytogenes did not survive after 1h under acidic conditions. These data demonstrated that Latin-style fresh cheese could play an important role in probiotic protection against gastrointestinal juices, enhancing delivery within the gut and thereby maximizing potential health benefits of LAB.
Journals
2015 EN
Camila Freitas Batista · Maiara Garcia Blagitz · Heloísa Godoi Bertag
+3 more
The immune system of newborn calves is immature and must mature gradually. Understanding how this immunity is established may define different profiles. Twelve healthy calves were monitored during 8 time periods to assess the innate immune system during the first 90d. Blood samples were collected, and the blood phagocytes, identified by the expression of CD14 and CH138 surface molecules, were evaluated for phagocytic functionality (Staphylococcus aureus and Escherichia coli stained with propidium iodide) and the intracellular production of reactive oxygen species (2,7'-dichlorofluorescein diacetate oxidation). Functional changes in the CD14+ and CH138+ cells occurred at 40d of age, with sporadic increases in phagocytosis intensity and reactive oxygen species production, and decreased phagocytosis occurred at 60d of age. Therefore, fewer phagocytes were active from 40d of age, although those that were active performed their roles with greater efficacy. That change presumably occurred because the calf phagocytes began to support the immune response without the influence of passive immunity. The animals failed to reach the stability needed to complete the maturation of the innate immune response by 90d of age. These data are applicable for healthy calves only.
Journals
2015 EN
Barbara Dal Bello · Luisa Torri · Maria Piochi
+1 more
The concentration of n-3 polyunsaturated fatty acids (PUFA) in yogurt was increased using 5 different vegetable oils obtained from flaxseed, Camelina sativa, raspberry, blackcurrant, and Echium plantagineum. The vegetable oils were added to partially skim milk before lactic fermentation at a concentration adequate enough to cover at least 10% of the recommended daily intake of 2 g/d of α-linolenic acid according to EC regulation no. 432/2012. Microbiological (lactobacilli and streptococci, yeast, and molds), chemical (pH, syneresis, proximate composition, fatty acids, oxidation stability), and sensory evaluations were assessed for all of the fortified yogurts after 0, 7, 14, and 21 d of storage at 4°C. Sensory evaluations were conducted at 21 d of storage at 4°C. Among the yogurts produced, those that were supplemented with flaxseed and blackcurrant oils exhibited the highest α-linolenic acid content (more than 200mg/100 g of yogurt) at the end of storage. The addition of oil did not influence the growth of lactic acid bacteria that were higher than 10(7) cfu/g at 21 d of storage. All of the yogurts were accepted by consumers, except for those supplemented with raspberry and E. plantagineum oils due to the presence of off flavors.
Journals
2015 EN
Samira A.L. Fiordalisi · Luciana Aparecida Honorato · Márcia Regina Loiko
+4 more
The objective of this study was to evaluate in vitro the antimicrobial activity of Brazilian propolis from Urupema, São Joaquim, and Agua Doce (Santa Catarina State) and green propolis from Minas Gerais State, and the effects of propolis on bovine mammary gland explant viability. The propolis samples differed in flavonoid content and antioxidant activity. Green propolis showed the highest content of flavonoids, followed by the sample from São Joaquim. The propolis from Urupema showed the lowest flavonoid content along with the lowest antioxidant activity. The total phenolics were similar across all studied samples. Despite phytochemical differences, the propolis samples from Minas Gerais, São Joaquim, and Urupema presented the same level of antimicrobial activity against Staphylococcus aureus strains. The reduction in S. aureus growth was, on average, 1.5 and 4 log10 times at 200 and 500 μg/mL, respectively. At concentrations of 1,000 μg/mL, all propolis reduced bacterial growth to zero. On the other hand, when the propolis were tested against strains of Escherichia coli, the samples presented weak antimicrobial activity. Mammary explants were maintained in culture for 96h without a loss in viability, demonstrating the applicability of the model in evaluating the toxicity of propolis. The origin and chemical composition of the propolis had an effect on mammary explant viability. We encountered inhibitory concentrations of 272.4, 171.8, 63.85, and 13.26 μg/mL for the propolis from Água Doce, Urupema, São Joaquim, and Mina Gerais, respectively. A clear association between greater antimicrobial activity and toxicity for mammary explants was observed. Of all propolis tested, the Urupema sample was noteworthy, as it showed antimicrobial activity at less toxic concentrations than the other samples, reducing bacterial growth to an average of 9.3 × 10(2) cfu/mL after 6h of contact using 200 μg/mL of extract. The results demonstrate the potential for Brazilian propolis in the treatment of mastitis, although effectiveness is dependent on geographical origin and concentration. The results from the mammary gland explant assays are promising for the investigation of other natural products with antimicrobial and anti-inflammatory properties that can be used in the intramammary treatment of subclinical mastitis and during dry cow therapy.
Journals
2015 EN
Elvia Cruz-Huerta · Daniel Martínez Maqueda · Lucía de la Hoz
+4 more
Peptides with iron-binding capacity obtained by hydrolysis of whey protein with Alcalase (Novozymes, Araucaria, PR, Brazil), pancreatin, and Flavourzyme (Novozymes) were identified. Hydrolysates were subjected to iron (III)-immobilized metal ion affinity chromatography, and the bound peptides were sequenced by mass spectrometry. Regardless of the enzyme used, the domains f(42-59) and f(125-137) from β-lactoglobulin enclosed most of identified peptides. This trend was less pronounced in the case of peptides derived from α-lactalbumin, with sequences deriving from diverse regions. Iron-bound peptides exhibited common structural characteristics, such as an abundance of Asp, Glu, and Pro, as revealed by mass spectrometry and AA analysis. In conclusion, this characterization of iron-binding peptides helps clarify the relationship between peptide structure and iron-chelating activity and supports the promising role of whey protein hydrolysates as functional ingredients in iron supplementation treatments.