1,721,035 research outputs found
Genetic and phenotypic variability of milk coagulation properties, cheese yield, nutrients recoveries and cheese sensory properties assessed on individual milk of Brown Swiss cows
Full text linkMilk cheese-making ability have received great interest from the dairy industry in the worldwide increasing of the amount of milk used for cheese production. In recent years, scientific research was mainly occupied to identify and study phenotypic and genetic variability of milk coagulation properties. The relationship between these traits and cheese yield is not entirely clear. Cheese yield, milk nutrients recoveries in the curd and whey losses represent indices that defines the efficiency of the cheese-making process and are used as tools for economic control in the dairies. To our knowledge, any studies have not yet been proposed on the assessing of yield and quality traits of individual cheese variability using bovine milk. These traits are influenced by environmental and genetic factors.
In the present thesis quality cheese-making traits of milk from individual cows of the Brown Swiss were assessed. In particular, this study has focused on the milk coagulation properties, the cheese yield, the nutrients recoveries in the curd and, finally, the quality ( chemical components, physical traits and sensory properties) of cheese.
Milk coagulation properties were compared through a traditional mechanical device and a near-infrared optical device. This comparison of MCP traits (RCT, k20, a30, a45) has emphasized phenotypic and genetic differences between measures obtained by the two devices, especially for samples coagulating after 30 minutes (NC samples) from start analysis. Rennet coagulation time (RCT) was the trait presenting less differences when assesses by a different instrument. Extending the analysis the analysis by either instruments allowed to: obtain RCT for all samples analysed, estimate a new curd firmness trait (a45; the width of the resulting graph after 45 min from the rennet addition), estimate the heritability of k20 and a45 and genetic correlations with the milk production and qualitative traits. The results obtained suggested the use of the optical instrument for the assessment of the first phase of coagulation process where the chemical-physical changes of the milk are not visible.
Cheese yield was estimated by developing an individual model-cheese production procedure 1500 ml of milk per sample. The described model cheese-producing procedure and the obtained results provide new insight into variation and relationships among different cheese yield (curd, dry matter and water) and recovery (protein, fat, dry matter and energy) traits at the individual level.
The results showed high milk quality of milk Brown Swiss breed presenting on average a cheese yield of 15%. Measures of nutrient recoveries (protein, fat, total solids and energy) were computed exhibiting a great variability. It has been observed that the yield is not only influenced by the milk dry matter but also by the milk water. From a genetic point of view, heritability has been estimated for cheese yield (of the curd, the dry matter and water) and the recovery of nutrients in the curd (protein, fat, dry matter and energy) and the results have shown a certain importance of genetic factors on the variability of these traits. Clearly, additional research on this topic is warranted, especially in terms of assessing the genetic background of these traits and the methods for their indirect prediction.
Finally, it was evaluated the qualitative traits and sensory properties of cheeses produced at the individual level (from each cow). The results showed a great variability of these traits at individual level. From the variation factors considered in this study, stage of lactation appeared to be important reflecting the changes in milk composition, while order of parity did not show any significant relationship with the analysed traits. cheese composition and few sensory properties (related to the cheese texture), were influenced by the cheese yield of milk. Collection of these data at the individual level will also allow to estimate genetic parameters of these traits.L’attitudine del latte alla caseificazione rappresenta un argomento che desta molto interesse per l’aumento della quota prodotta della materia prima destinata alla produzione di formaggio. Negli ultimi anni la ricerca scientifica si è occupata soprattutto della determinazione ed identificazione delle proprietà di coagulazione del latte atte ad essere impiegate come fattore di valutazione e, di riflesso, come possibile carattere obiettivo di selezione nelle vacche da latte. Ad oggi, la relazione tra le proprietà di coagulazione del latte e la resa casearia non è del tutto chiara. La resa in formaggio rappresenta l’indice che definisce l’efficienza del processo di caseificazione ed è per questo utilizzato come strumento di controllo economico nei caseifici. Non sono stati ancora proposti degli studi che vadano a porre l’attenzione su fenotipi legati alla resa casearia ed alla qualità del formaggio prodotto dal latte individuale di specie bovina. Tali caratteristiche variano in funzione di una serie di fattori sia di natura ambientale che genetica.
Con la presente tesi sono stati presi in considerazione i caratteri che definiscono l’attitudine casearia del latte individuale di vacche di razza Brown Swiss. In particolare, l’indagine scientifica ha riguardato le proprietà di coagulazione del latte, la resa casearia e le perdite nel siero dei componenti del latte ed, infine, la qualità del formaggio tramite la analisi fisico-chimica e sensoriale.
La valutazione delle proprietà di coagulazione del latte ha previsto l’utilizzo di due strumenti che presentano tecnologie di funzionamento differenti (meccanico ed ottico). Il confronto degli stessi caratteri (RCT, k20, a30, a45) ottenuti con i due strumenti ha sottolineato differenze sia da un punto di vista fenotipico che da un punto di vista genetico, soprattutto per i campioni di latte coagulanti dopo 30 minuti dall’inizio dell’analisi. Il tempo di coagulazione (RCT) è stato il parametro in cui sono state riscontrate minori differenze tra i risultati ottenuti dai due differenti strumenti. L’aumento della durata dell’analisi a 90 minuti ha permesso di: ottenere l’RCT per tutti i campioni analizzati, stimare un nuovo parametro di consistenza del coagulo a 45 minuti dall’inizio dell’analisi (a45), determinare l’ereditabilità e le correlazioni genetiche con i caratteri qualitativi del latte per il k20 ed anche per l’a45. I risultati ottenuti suggeriscono l’eventuale utilizzo dello strumento ottico per la valutazione delle primissime fasi del processo di coagulazione dove i cambiamenti chimico-fisici del latte non sono visibili.
La resa casearia è stata determinata mettendo a punto una procedura di micro caseificazione utilizzando 1500 ml di latte per campione. I risultati ottenuti hanno evidenziato un’elevata qualità del latte di razza bruna con una resa media a fresco del 15% circa. È stato possibile stimare il recupero nella cagliata dei componenti del latte: questi caratteri non sono risultati costanti ma è stata osservata una certa variabilità sulla base dei fattori presi in considerazione nel presente studio (stadio di lattazione, ordine di parto, produzione di latte). È stato osservato che la resa non è influenzata solamente dalla materia utile del latte ma anche dall’acqua. Da un punto di vista genetico, è stata stimata per la prima volta nel latte bovino, l’ereditabilità della resa casearia (della cagliata, della sostanza secca e dell’acqua) e del recupero di nutrienti nella cagliata (proteina, grasso, sostanza secca ed energia). I risultati ottenuti hanno evidenziato la presenza di una rilevante componente genetico additiva degli animali, potenzialmente sfruttabile per finalità selettive.
Infine, sono state valutate le caratteristiche qualitative ed organolettiche dei formaggi prodotti a livello individuale. Dallo studio delle potenziali fonti di variazione è emerso che lo stadio di lattazione risulta essere un fattore altamente significativo. Tale effetto influenza i cambiamenti di composizione del latte durante la fase produttiva della vacca, mentre l’ordine di parto non ha evidenziato alcun legame importante con i caratteri analizzati. Alcuni parametri, soprattutto quelli relativi alla texture, sembrano legati alla resa casearia del latte. La raccolta di questi caratteri, a livello individuale, permetterà anche la stima dei parametri genetici
Milk protein fractions strongly affect the patterns of coagulation, curd firming, and syneresis
Full text linkThe aim of this study was to assess the role of milk protein fractions in the coagulation, curd firming, and syneresis of bovine milk. Analyses were performed on 1,271 individual milk samples from Brown Swiss cows reared in 85 herds classified into 4 types of farming sys- tems, from the very traditional (tied cows, feed manu- ally distributed, summer highland pasture) to the most modern (loose cows, use of total mixed rations with or without silage). Fractions αS1-casein (CN), αS2-CN, β-CN, κ-CN, β-lactoglobulin (LG), and α-lactalbumin (LA) and genotypes at CSN2, CSN3, and BLG were obtained by reversed-phase HPLC. The following milk coagulation properties were measured with a lactody- namograph, with the testing time extended to 60 min: rennet coagulation time (RCT, min), curd firming time (min), and curd firmness at 30 and 45 min (mm). All the curd firmness measures recorded over time (total of 240 observations/sample) were used in a 4-parameter nonlinear model to obtain parameters of coagulation, curd firming, and syneresis: RCT estimated from the equation (min), asymptotic potential curd firmness (mm), the curd firming and syneresis instant rate con- stants (%/min), and the maximum curd firmness value (CFmax, mm) and the time taken to reach it (min). All the aforementioned traits were analyzed with 2 linear mixed models, which tested the effects of the protein fractions expressed in different ways: in the first, quan- titative model, each protein fraction was expressed as content in milk; in the second, qualitative model, each protein fraction was expressed as a percentage of total casein content. Besides proteins, additional nuisance parameters were herd (included as a random effect), daily milk production (only for the quantitative model), casein content (only for the qualitative model), dairy system, parity, days in milk, the pendulum of the lactodynamograph, and the CSN2, CSN3, and BLG genotypes. Both αS1-CN and β-CN showed a clear and favorable effect on CFmax, where the former effect was almost double the latter. Milk coagulation ability was favorably affected by κ-CN, which reduced both the RCT and RCT estimated from the equation, increased the curd firming and syneresis instant rate constants, and allowed a higher CFmax to be reached. In contrast, αS2-CN delayed gelation time and β-LG worsened curd firming, both resulting in a low CFmax. The results of this study suggest that modification of the relative con- tents of specific protein fractions can have an enormous effect on the technological behavior of bovine milk
Direct and indirect predictions of enteric methane daily production, yield, and intensity per unit of milk and cheese, from fatty acids and milk Fourier-transform infrared spectra
No full textMitigating the dairy chain's contribution to climate change requires cheap, rapid methods of predicting enteric CH4 emissions (EME) of dairy cows in the field. Such methods may also be useful for genetically improving cows to reduce EME. Our objective was to evaluate different procedures for predicting EME traits from infrared spectra of milk samples taken at routine milk recording of cows. As a reference method, we used EME traits estimated from published equations developed from a meta-analysis of data from respiration chambers through analysis of various fatty acids in milk fat by gas chromatography (FA(GC)). We analyzed individual milk samples of 1,150 Brown Swiss cows from 85 farms operating different dairy systems (from very traditional to modern), and obtained the cheese yields of individual model cheeses from these samples. We also obtained Fourier-transform infrared absorbance spectra on 1,060 wavelengths (5,000 to 930 waves/cm) from the same samples. Five reference enteric CH4 traits were calculated: CH4 yield (CH4/DMI, g/kg) per unit of dry matter intake (DMI), and CH4 intensity (CH4/CM, g/kg) per unit of corrected milk (CM) from the FA(GC) profiles; CH4 intensity per unit of fresh cheese (CH4/CYCURD, g/kg) and cheese solids (CH4/CYSOLIDS, g/kg) from individual cheese yields (CY); and daily CH4 production (dCH(4), g/d). Direct infrared (IR) calibrations were obtained by BayesB modeling; the determination coefficients of cross-validation varied from 0.36 for dCH(4) to 0.57 for CH4/CM, and were similar to the coefficient of determination values of the equations based on FAGC used as the reference method (0.47 for CH4/DMI and 0.54 for CH4/CM). The models allowed us to select the most informative wavelengths for each EME trait and to infer the milk chemical features underlying the predictions. Aside from the 5 direct infrared prediction calibrations, we tested another 8 indirect prediction models. Using IR-predicted informative fatty acids (FA(IR)) instead of FA(GC), we were able to obtain indirect predictions with about the same precision (correlation with reference values) as direct IR predictions of CH4/DMI (0.78 vs. 0.76, respectively) and CH4/CM (0.82 vs. 0.83). The indirect EME predictions based on IR-predicted CY were less precise than the direct IR predictions of both CH4/CYCURD (0.67 vs. 0.81) and CH4/CYSOLIDS (0.62 vs. 0.78). Four indirect dCH(4) predictions were obtained by multiplying the measured or IR-predicted daily CM production by the direct or indirect CH4/CM. Combining recorded daily CM and predicted CH4/CM greatly increased precision over direct dCH(4) predictions (0.96-0.96 vs. 0.68). The estimates obtained from the majority of direct and indirect IR-based prediction models exhibited herd and individual cow variability and effects of the main sources of variation (dairy system, parity, days in milk) similar to the reference data. Some rapid, cheap, direct and indirect IR prediction models appear to be useful for monitoring EME in the field and possibly for genetic/genomic selection, but future studies directly measuring CH4 with different breeds and dairy systems are needed to validate our findings
Factors affecting variation of different measures of cheese yield and milk nutrient recovery from an individual model cheese-manufacturing process
No full textCheese yield (CY) is the most important technological trait of milk, because cheese-making uses a very high proportion of the milk produced worldwide. Few studies have been carried out at the level of individual milk-producing animals due to a scarcity of appropriate procedures for model-cheese production, the complexity of cheese-making, and the frequent use of the fat and protein (or casein) contents of milk as a proxy for cheese yield. Here, we report a high-throughput cheese manufacturing process that mimics all phases of cheese-making, uses 1.5-L samples of milk from individual animals, and allows the simultaneous processing of 15 samples per run. Milk samples were heated (35 C for 40 mm), inoculated with starter culture (90 mm), mixed with rennet (51.2 international milk-clotting units/L of milk), and recorded for gelation time. Curds were cut twice (10 and 15 mm after gelation), separated from the whey, drained (for 30 min), pressed (3 times, 20 mm each, with the wheel turned each time), salted in brine (for 60 mm), weighed, and sampled. Whey was collected, weighed, and sampled. Milk, curd, and whey samples were analyzed for pH, total solids, fat content, and protein content, and energy content was estimated. Three measures of percentage cheese yield (%CY) were calculated: %CYCURD, %CYSOLIDS and %CYWATER) representing the ratios between the weight of fresh curd, the total solids of the curd, and the water content of the curd, respectively, and the weight of the milk processed. In addition, 3 measures of daily cheese yield (dCY, kg/d) were defined, considering the daily milk yield. Three measures of nutrient recovery (REC) were computed: RECFAT, RECPROTEIN, and RECSOLIDS, which represented the ratio between the weights of the fat, protein, and total solids in the curd, respectively, and the corresponding components in the milk. Energy recovery, RECENERGY) represented the energy content of the cheese compared with that in the milk. This procedure was used to process individual milk samples obtained from 1,167 Brown Swiss cows reared in 85 herds of the province of Trento (Italy). The assessed traits exhibited almost normal distributions, with the exception of RECFAT. The average values (SD) were as follows: %CYCURD = 14.97 1.86, %CYSOLIDS = 7.18 +/- 0.92, %CY - WATER 7.77 1.27, dCY(CURD) = 3.63 +/- 1.17, dCY(SOLIDS) = 1.74 0.57, dCY(WATER) = 1.88 +/- 0.63, RECFAT = 89.79 3.55, RECPROTEIN = 78.08 +/- 2.43, 51.88 3.52, and RECENERGY = 67.19 3.29. All traits were highly influenced by herd-test-date and days in milk of the cow, moderately influenced by parity, and weakly influenced by the utilized vat. Both %CYCURD and dCY(CURD) depended not only on the fat and protein (casein) contents of the milk, but also on their proportions retained in the curd; the water trapped in curd presented an higher variability than that of %CYSOLIDS. All REC traits were variable and affected by days in milk and parity of the cows. The described model cheese-making procedure and the results obtained provided new insight into the phenotypic variation of cheese yield and recovery traits at the individual level
Potential influence of herd and animal factors on the yield of cheese and recovery of components from Sarda sheep milk, as determined by a laboratory bench-top model cheese-making
No full textIndividual milk samples from 169 Sarda sheep were collected to characterise the cheese-making potential through the use of a laboratory bench-top model cheese-manufacturing procedure. As the milk samples were not standardised before processing, the data collected at laboratory level fully reflected the great variability of milk from individual animals. The average cheese yield traits of fresh cheese, cheese dry matter and water retained in cheese (as percentages of the milk processed) were 20.6%, 10.1% and 10.6%. The average milk fat and protein recoveries in the curd were 94.0% and 76.7%, respectively. The values for daily production of curd and curd dry matter per sheep were 0.41 kg d−1 and 0.20 kg d−1, respectively. The cheese yield and cheese-related traits were mainly affected by the nutrient content of the milk and the individual effects of the stage of lactation and daily milk yield, respectively, but also by a large individual variatio
The 9-MilCA method as a rapid, partly automated protocol for simultaneously recording milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss
No full textThe aim of this study was to propose and test a new laboratory cheesemaking procedure [9-mL milk cheesemaking assessment (9-MilCA)], which records 15 traits related to milk coagulation, curd firming, syneresis, cheese yield, and curd nutrients recovery or whey loss. This procedure involves instruments found in many laboratories (i.e., heaters and lacto-dynamographs), with an easy modification of the sample rack for the insertion of 10-mL glass tubes. Four trials were carried out to test the 9-MilCA procedure. The first trial compared 8 coagulation and curd firming traits obtained using regular or modified sample racks to process milk samples from 60 cows belonging to 5 breeds and 3 farms (480 tests). The obtained patterns exhibited significant but irrelevant between-procedure differences, with better repeatability seen for 9-MilCA. The second trial tested the reproducibility and repeatability of the 7 cheesemaking traits obtained using the 9-MilCA procedure on individual samples from 60 cows tested in duplicate in 2 instruments (232 tests). The method yielded very repeatable outcomes for all 7 tested cheese yield and nutrient recovery traits (repeatability >98%), with the exception of the fresh cheese yield (84%), which was affected by the lower repeatability (67%) of the water retained in the curd. In the third trial (96 tests), we found that using centrifugation in place of curd cooking and draining (as adopted in several published studies) reduced the efficiency of whey separation, overestimated all traits, and worsened the repeatability. The fourth trial compared 9-MilCA with a more complex model cheese-manufacturing process that mimics industry practices, using 1,500-mL milk samples (72 cows, 216 tests). The average results obtained from 9-MilCA were similar to those obtained from the model cheeses, with between-method correlations ranging from 78 to 99%, except for the water retained in the curd (r = 54%). Our results indicate that new 9-MilCA method is a powerful research tool that allows the rapid, inexpensive, and partly automated analysis processing 40 samples per day with 2 replicates each, using 1 lacto-dynamograph, 2 heaters, and 3 modified sample racks, and yields a complete picture of the cheesemaking process (e.g., milk gelation, curd firming, syneresis, and whey expulsion) as well as the cheese yield and the efficiency of energy or nutrients retention in the cheese or loss in the whey
Variation of milk coagulation properties, cheese yield, and nutrients recovery in curd of cows of different breeds before, during and after transhumance to highland summer pastures
No full textThis paper aimed at evaluating the effect of summer transhumance to mountain pastures of dairy cows of different breeds on cheese-making ability of milk. Data were from 649 dairy cows of specialized (Holstein Friesian and Brown Swiss) dual purpose (Simmental) and local (mostly Rendena and Alpine Grey) breeds. The Fourier-Transform Infra-Red Spectra (FTIRS) of their milk samples were collected before and after transhumance in 109 permanent dairy farms, and during transhumance in 14 summer farms (with multi-breeds herds) of the Trento Province, north-eastern Italy. A variety of 18 traits describing milk coagulation, curd firming, cheese yield and nutrients recovery in curd/loss in whey were predicted on the basis of FTIRS collected at the individual cow level. Moving the cows to summer farms improved curd firming traits but reduced cheese yields because of an increase of water and fat lost in the whey. During summer grazing, most of cheesemaking traits improved, often non-linearly. The milk from summer farms supplementing cows with more concentrates showed better curd firming and cheese yield, because of lower fat lost in the whey. The breed of cows affected almost all the traits with a worst cheese-making ability for milk samples of Holsteins through all the trial, and interacted with concentrate supplementation because increasing compound feed tended to improve cheese-making traits for all breed, with the exception of local breeds for coagulation time and of Brown Swiss for curd firming time. In general, summer transhumance caused a favourable effect on cheese-making aptitude of milk, even though with some difference according to parity, initial days in milk, breed and concentrate supplementation of cows
Coagulation properties and composition of milk of crossbred cows compared with Holstein cows
No full textPhenotypic analysis of cheese yields and nutrient recoveries in the curd of buffalo milk, as measured with an individual model cheese-manufacturing process
No full textTraits associated with cheese yield and milk nutrient recovery in curd are used to describe the efficiency of the cheese-making process. This is fundamental for all dairy species, including the Italian Mediterranean buffalo, which is largely used for milk production aimed at the dairy industry. To assess cheese-making traits among buffalo, a model cheese-manufacturing process was tested; it was capable of processing 24 samples per run, using 0.5-L samples of milk from individual buffalo. In total, 180 buffalo reared in 7 herds located in Northeast Italy were sampled once. Briefly, each sample was weighed and heated (35 degrees C for 30 min), inoculated with starter culture (90 min), and mixed with rennet (51.2 international milk-clotting units/L of milk). After 10 mm of gelation, the curd was cut; 5 mm after the cut, the curd was separated from the whey, and the curd was subjected to draining (for 30 mm) and pressing (18 h). The curd and whey were weighed, analyzed for pH and the total solid, fat, lactose, and protein contents, and subjected to estimation of the energy content. Three measures of cheese yield (%CY), %CYCURD, %CYSOLIDS and %CYWATER, were computed as the ratios between the weight of the curd, the curd dry matter, and the water retained in the curd, respectively, and the weight of the milk processed. These traits were multiplied by the daily milk yield to define the 3 corresponding measures of daily cheese yield (dCY, kg/d). The milk component recoveries (REC) in the curd, RECFAT, RECPROTEIN, and RECSOLIDS, represented the ratios between the weights of the fat, protein, and total solids in the curd, respectively, and the corresponding components in the milk. Finally, energy recovery (RECENERGY) was estimated. The values for %CYCURD, %GY(SOLIDS), %CYWATER, RECPROTEIN, RECFAT, RECSOLIDS and RECENERGY averaged 25.6, 12.7, 12.9, 80.4, 95.1, 66.7, and 79.3%, respectively, indicating that buffalo milk has a higher aptitude to cheese-making than bovine milk. The effect of days in milk was the most important source of variation for %CY, RECPROTEIN, and the overall recoveries (which showed higher values toward the end of lactation), whereas parity did not appear to influence any of the investigated traits. The cheese-making procedure tested allowed us to assess the variability of and relationships among different cheese yield traits, recovery traits, daily milk production traits, and milk components at the individual level
Variation in caprine milk composition and coagulation as affected by udder health indicators
No full text- …
