Characteristics Of Curd Research Articles

Production of Acid and Rennet-Coagulated Cheese Enriched by Olive (Olea europaea L.) Leaf Extract-Determining the Optimal Point of Supplementation and Its Effects on Curd Characteristics.

This study investigated the potential of olive leaf extract (OLE), as a functional ingredient, to improve cheese properties, because it is rich in phenols. Milk and dairy products are poor in phenolic compounds. The main objective was to determine the most effective coagulation method and timing of OLE supplementation to maximize retention in the cheese matrix. Experimental cheeses were produced using the rennet and acid coagulation methods, with OLE added either directly to the cheese milk or to the curd phase. Three OLE effective concentrations corresponding to 25%, 50%, and 75% inhibition of DPPH reagent (EFC25, EFC50, and EFC75, respectively) were added, i.e., 11.5 mg GAE L-1, 16.6 mg GAE L-1, and 26.3 mg GAE L-1, respectively. The results showed that OLE significantly increased the concentration of total phenols, total flavonoids, and antioxidant activity in all cheese samples and in the residual whey, especially at higher effective concentrations (EFC 50 and EFC 75). Rennet-coagulated cheese to which OLE was added prior to coagulation (EM 25, EM 50, EM 75) exhibited higher hardness, gumminess, and chewiness but lower elasticity, suggesting alterations in the paracasein matrix. OLE did not adversely affect acidity, water activity, or cheese yield. However, higher EFC resulted in significant colour changes (∆E* > 3.0). In conclusion, the enrichment of cheesemaking milk with OLE and the application of the rennet coagulation method are the most suitable to optimise the production of OLE-enriched cheese. This research shows the potential to improve the nutritional value of cheese while maintaining its desired characteristics.

Drought-induced changes in plant-yield interlinked biochemistry of cauliflower (Brassica oleracea L. var. botrytis) by exogenously applied alpha-tocopherol

To assess the potential of exogenously-applied vitamin E commonly known as alpha-tocopherol (α-TOC) in drought stress tolerance, an experiment was performed on cauliflower (Brassica oleracea L. var. botrytis) plants. Two cultivars (TCF-605 and White Figer) of cauliflower were subjected to control and drought stress conditions. After thirty days of drought stress treatment, cauliflower plants were treated with α-TOC (150 and 300 mg/L) as a foliage spray. Drought stress markedly inhibited the plant biomass, leaf characteristics such as relative water contents (RWC), chlorophyll pigments (a and b), proline, ascorbic acid (AsA), GB, however it elevated RMP, total phenolics, activities of antioxidant enzymes e.g., CAT, SOD and POD. Drought stress also adversely affected curd characteristics including its fresh weight, GB, proline, total phenolics and enzymes activities (SOD and CAT). Exogenously applied α-TOC considerably suppressed RMP, while it improved plant growth, yield, RWC, total phenolics, ascorbic acid and POD, SOD, and CAT enzyme activities in the leaves of the cauliflower. Exogenous application of α-TOC also raised curd total phenolics, AsA and the activities of all observed enzymes under water deficiency. The cv. TCF-605 was better in shoot weight, shoot length, RWC, proline as well as GB contents, while cv. White Figer was higher in leaf RMP, proline and AsA levels under drought stress conditions. Overall, the results exhibited that cauliflower cv. TCF-605 was relatively tolerant to water stress in relation to growth and yield outcomes, which was interlinked with α-TOC-induced improved leaf and curd osmoprotection and antioxidative defense system. So, exogenous application of α-TOC can be suggested for improving growth and yield potential of crops subjected to drought stress.

The influence of unconventional ultrasonic pasteurization on the characteristics of curds obtained from goat milk with the low cholesterol content

This study aimed to evaluate the influence of different power-time ultrasound regimes of pasteurization on the physical, chemical, organoleptic properties, and lipid quality indices of goat curds characterized by a low cholesterol level. Cholesterol was eliminated by a percentage of 92.1 % by treating the raw goat milk with beta-cyclodextrin in the proportion of 0.6 %. Afterward, the goat milk was subjected to the following ultrasound regimes: 320 W for 1 (PA1), 3 (PA3), and 6 min (PA6) and 881 W for 1 (PP1), 3 (PP3), and 6 min (PP6) and then used for the curds production. Due to the ultrasound treatment, the milk suffered a concentration phenomenon, the most accentuated being registered for the PP6 sample. Considering the sensory properties, the most appreciated curd was the one obtained by the PP6 regime which recorded the highest scores for color and taste. Regarding the microbiological aspects, the ability of ultrasounds to inactivate microorganisms is observed and the most accentuated phenomenon is reported in the PP6 case. Thus, in comparison with the control sample, the total number of germs is reduced by a proportion of 91.85 %, the β-glucuronidase-positive Escherichia coli decreased by 93.15 %, while the coagulase-positive staphylococci were completely inactivated for the PP6 curd. The curds obtained for the PA6 and PP6 regimes registered the highest dry matter values as a cause of an accentuated syneresis process. The acidity values were higher for the curds obtained for PA1, PA3, and PA6 regimens due to more pronounced lactose hydrolysis and lower in the cases of PP3 and PP6 regimens compared to the control cheese. Twenty-five saturated, monounsaturated, and polyunsaturated fatty acids were identified in the curd samples and a rise in the unsaturated fatty acids proportion as the intensity of the applied ultrasound regime increased was observed. Also, AI, TI, and H/H lipid quality indices recorded better values as the power and time of the ultrasound action increased.

The Influence of Unconventional Ultrasonic Pasteurization on the Characteristics of Curds Obtained from Goat Milk with Low Cholesterol Content

The Influence of Unconventional Ultrasonic Pasteurization on the Characteristics of Curds Obtained from Goat Milk with Low Cholesterol Content

Effect of Water Temperature and Time during Heating on Mass Loss and Rheology of Cheese Curds.

During the manufacturing of mozzarella, cheese curds are heated to the desired stretching temperature traditionally by immersion in water, which influences the curd characteristics before stretching, and consequently the final cheese properties. In this study, cheese curds were immersed in hot water at 60, 70, 80 and 90 °C up to 16 min and the kinetics of mass loss and changes of rheological properties were investigated. The total mass of cooked curds increased up to 10% during the first minute, independent of the temperature, as a consequence of water retention. Fat was the main component lost into the cooking water (<3.5% w/w), while the concentration of protein increased up to 3.4% (w/w) compared to uncooked curds due to the loss of other components. Curds macrostructure during cooking showed that curds fully fuse at 70 °C/4 min; 80 °C/2 min and 90 °C/1 min, while after intensive cooking (>8 min) they lost the ability to fuse as a consequence of protein contraction and fat loss. Storage modulus, representing the curd strength, was dependent on cooking temperature and positively, and linearly, correlated with curd protein content (21.7–24.9%). This work shows the potential to modify curd composition and structure, which will have consequences for further processing and final product properties.

Characteristics of Curds With Milk Clotting Enzyme from Indonesian Local Isolate of Lactic Acid Bacteria

To get the potential of lalcat acid bacteria isolate to produce Milk Clotting Enzyme (MCE), it is necessary to screen milk clotting activity both quantitatively and qualitatively. Through qualitative observation, the characteristics of the curd resulting from enzyme activity can be obtained. MCE is a protease that has the characteristics of milking. Based on the results of this observational research, the curd characteristic produced can be used as a benchmark to determine the length of time of fermentation and optimization of the determination of ammonium sulfate precipitation concentration. Isolate BAL shows the results of a compact curd at a fermentation time of 25 hours at 37 ℃ and the optimization results of the deposition of ammonium sulfate which shows the characteristics of a compact curd by 45% ammonium sulfate.

Fresh Cheese Probiotic with Local Isolate Lactobacillus casei 2.12 as starter in fermentation

The local isolates of Lactic Acid Bacteria (LAB) have not been optimally developed in the cheese making process. The aim of this research was to know the clotting activity and the percentage and characteristics of curd produced during milk fermentation using local isolate of BAL L casei 2.12. The results showed that during 12 hours incubation the value of milk clotting activity (MCA) was 8.33 SU / mL, the curd percentage was 12.5% (w / v) with curd firmness (++++) very good and Total Plate Count 1.14. 109 cfu / g. These results indicate the use of L casei 2.12 as a starter LAB probiotic capable of causing coagulation of casein and produce fresh cheese probiotic.

Effect of air velocity on heat transfer characteristics of curd during cooling in High Impact Polystyrene cups

Effect of air velocity on heat transfer characteristics of curd during cooling in High Impact Polystyrene cups

Dairy curd coagulated by a plant extract of Calotropis procera: Role of fat structure on the chemical and textural characteristics

Milk is often subjected to technological treatments which have impacts on the structure of milk constituents and the characteristics of rennet curds. In this paper, the influence of the dairy fat structure on the biochemical and textural characteristics of curds coagulated by an extract of Calotropis procera leaves was studied. Standardized milks were reconstituted with the same contents in protein (35g·kg−1) and fat (35g·kg−1) but with different structures of fat i.e. homogenized anhydrous milk fat (HAMF), homogenized cream (HC) and non-homogenized cream (NHC). As expected, the size distributions of fat globules in the different milks were different. After their coagulations by the plant extract, the physico-chemical characteristics of the curds and respective wheys were determined. No difference was observed in the coagulation time between the three milks but the whey removed more quickly from HAMF and HC curds than NHC-curd. The biochemical analyses of curds revealed a lower content in dry matter and fat in the NHC-curd compared to HAMF- and HC-curds. Otherwise, the NHC-whey exhibited the highest amount of fat. Observations by confocal microscopy showed that the fat globules were homogenously distributed and well trapped in the protein networks of HAMF- and HC-curds. In the NHC-curd, the fat globules were located in whey pockets, with less connectivity with the protein network. The textural analysis showed that the NHC-curd was more elastic, soft and adhesive than HAMF- and HC-curds. Homogenization significantly reduced the loss of fat during cheese manufacturing and conferred specific textural characteristics to the curds coagulated by an extract of Calotropis procera.

The influence of cryopowder “Garbuz” on the technology of curds of different fat content

The prospects and usefulness of the cryopowder “Garbuz”, the unified dietary supplement, to improve the organoleptic and physicochemical parameters, and also to increase the biological value of curds are considered. The focus is given to formulations of sweet and salty curds with the cryopowder “Garbuz”. It is found that the content of the cryoadditive “Garbuz” in salty curds is lower than in sweet. The cryoadditive quantity is increased as a result of increasing the fat content in a milk base. The research of the organoleptic characteristics of curds with the cryopowder “Garbuz” found that salty curds with the cryoadditive had a yellow color, while sweet curds had a cream color with individual yellowish inclusions of the cryoadditive powder. The flavor of salty curds remained fresh, sour-milk, while in sweet curds there was a clearly pronounced flavor of the cryoadditive. Pilot samples of sweet curds had a pronounced taste. The consistency of curds with the cryopowder “Garbuz” was uniform, pasty, soft. Pilot samples had a nice presentation. Introduction of the cryopowder “Garbuz” in curds increased their energy value. The proposed products expand the range of therapeutic and preventive dairy.

Derivation of multivariate indices of milk composition, coagulation properties, and individual cheese yield in dairy sheep

Milk composition and its technological properties are traits of interest for the dairy sheep industry because almost all milk produced is processed into cheese. However, several variables define milk technological properties and a complex correlation pattern exists among them. In the present work, we measured milk composition, coagulation properties, and individual cheese yields in a sample of 991 Sarda breed ewes in 47 flocks. The work aimed to study the correlation pattern among measured variables and to obtain new synthetic indicators of milk composition and cheese-making properties. Multivariate factor analysis was carried out on individual measures of milk coagulation parameters; cheese yield; fat, protein, and lactose percentages; somatic cell score; casein percentage; NaCl content; pH; and freezing point. Four factors that were able to explain about 76% of the original variance were extracted. They were clearly interpretable: the first was associated with composition and cheese yield, the second with udder health status, the third with coagulation, and the fourth with curd characteristics. Factor scores were then analyzed by using a mixed linear model that included the fixed effect of parity, lambing month, and lactation stage, and the random effect of flock-test date. The patterns of factor scores along lactation stages were coherent with their technical meaning. A relevant effect of flock-test date was detected, especially on the 2 factors related to milk coagulation properties. Results of the present study suggest the existence of a simpler latent structure that regulates relationships between variables defining milk composition and coagulation properties in sheep. Heritability estimates for the 4 extracted factors were from low to moderate, suggesting potential use of these new variables as breeding goals.

Обґрунтування складу заквашувальної композиції для виробництва йогурту функціонального призначення

Basing on the analysis of the Ukrainian functional food market, the article shows development prospects for new kinds of yoghurt with enhanced functional qualities using starter compositions of lactobacilli and bifidus bacteria consortium in the formula. It grounds the choice of lactobacilli bacterial concentrates («GoodFood») and probiotic cultures B. longum and E. faecium («Bifiform») of direct application for starter composition development in functional yoghurts production. The article studies organoleptic, physicochemical and microbiological characteristics of curds produced from milk formula fermentation using mixture of bacterial concentrates «GoodFood» and «Bifiform». It also shows the potential of lactobacilli and bifidus bacteria combination found in the above mentioned bacterial concentrates and in starter compositions for functional yoghurts production. It also shows the necessity for enrichment of the milk formula with fructose as a bifidogenic factor.The article grounds the starter composition formula for functional yoghurts production which has consortium of cultures Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueski subsp. bulgaricus, Lactobacillus acidophillus, Enterococcus faecium and Bifidobacterium longum of 1:1:1:1 ratio with initial concentration of all the cultures in the milk formula of 1·106 CFU/cm3. It defines organoleptic, physicochemical and microbiological characteristics of fermented curds produced by using of recommended lactobacilli and bifidus bacteria starter composition and shows that these curds may be the base for production of functional yoghurts with extended storage period.

Persistence of wild Streptococcus thermophilus strains on wooden vat and during the manufacture of a traditional Caciocavallo type cheese

The present work was undertaken to evaluate the influence of the wooden dairy plant equipment on the microbiological characteristics of curd to be transformed into Caciocavallo Palermitano cheese. Traditional raw milk productions were performed concomitantly with standard cheese making trials carried out in stainless steel vat inoculated with a commercial starter. Milk from two different farms (A and B) was separately processed. The wooden vat was found to be a reservoir of lactic acid bacteria (LAB), while unwanted (spoilage and/or pathogenic) microorganisms were not hosted or were present at very low levels. All microbial groups were numerically different in bulk milks, showing higher levels for the farm B. LAB, especially thermophilic cocci, dominated the whole cheese making process of all productions. Undesired microorganisms decreased in number or disappeared during transformation, particularly after curd stretching. LAB were isolated from the wooden vat surface and from all dairy samples, subjected to phenotypic and genetic characterization and identification. Streptococcus thermophilus was the species found at the highest concentration in all samples analyzed and it also dominated the microbial community of the wooden vat. Fourteen other LAB species belonging to six genera (Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Weissella) were also detected. All S. thermophilus isolates were genetically differentiated and a consortium of four strains persisted during the whole traditional production process. As confirmed by pH and the total acidity after the acidification step, indigenous S. thermophilus strains acted as a mixed starter culture.

Moisture sorption characteristics of curd (Indian yogurt) powder

The moisture sorption behaviour of curd (Indian yogurt) powder was studied at 20, 30, 40 and 50°C for water activity ranging from 0.07 to 0.85. GAB, BET, Henderson, Halsey, Chung &amp; Pfost, Smith, Oswin and Peleg models were applied to analyse the data. Estimated parameters and fitting ability for sorption models were evaluated. The GAB model showed the best fit to the sorption data of curd powder at 20, 30 and 40°C, and the Peleg model fitted well at 50°C.

Relationships between Italian Mediterranean Buffalo milk compounds

The percentages of dry matter (DM), protein, casein, fat, lactose, solids-not-fat and ash of milk and the characteristics of the curd (31 components and/or characteristics) were evaluated on 326 milk samples collected from 60 buffaloes every 50 days. The animals were half sib (same father or same mother ascertained by DNA test) and were bred in two farms. Relationships between the values of components and/or characteristics were also calculated. Significant relationships were found among DM percentage of milk and its components, cheese yield, curd characteristics, ratio between the studied cheese yields and protein percentage. Protein, casein and fat showed positive relationships, whereas lactose presented negative relationships. The association among proteins and real cheese yield or the dry matter of the curd that derived from 1 litre of milk (CDM), was lower than that with calculated cheese yield. This difference strongly decreased if proteins percentage, corrected for urea value, was utilized in cheese yield calculation. No relationship was found between proteins and urea in milk, but a direct relation was present between proteins and proteins adjusted for urea. This relation affects a correct estimation of cheese yield, because the percentage of true proteins in milk, corrected per urea was 4.52 vs. 4.64.

Relationships between buffalo milk components and curd characteristics

The aim of this study was to evaluate the coefficients of correlation between curd chemical composition and milk characteristics, theoretical and real cheese yield and ratios between cheese yield and protein percentage. The analysis were performed on 326 milk samples collected from 60 half sib buffaloes, ascertained by DNA test, every 50 days. The percentages of dry matter, proteins and fat of the curd were inversely correlated to the curd firmness (a30), a low enzymatic phase of coagulation and low pH value. Percentage of dry matter in the curd was positively correlated with proteins, casein and fat of the milk and negatively with lactose. Furthermore, dry matter and proteins percentages are also positively correlated with theoretical cheese yield and its ratio with real cheese yield, curd dry matter from 1 litre of milk and the ratio between curd dry matter and protein percentage. Negative correlations were found with real cheese yield at 28 hours (r = - 0.100; P< 0.01) and its ratio with protein percentage. An inverse relationship was highlighted between curd proteins percentage and fat of either milk and curd, while a direct association was present with lactose. A higher protein percentage in the curd was linked to a lower cheese yield and a lower ratio between cheese yield and proteins. Ash of the curd, finally, showed similar association to those described for proteins.

Milk and curd characteristics depending on farm and production level

Here reported are data relative to the chemical composition/characteristics of the milk, of milk samples collected every 50 days from 60 buffaloes (326 samples) that were half-sibs (through paternal or maternal lineage, ascertained by DNA test), bred in two farms (S.A. and M respectively n. = 27 and n = 33). The subjects were divided in relation to the productive level (> vs. < 2601 kg/lactation). The production level did not influence the theoretical yield (ThCY), the yield at 4 h (FCY) and at 28 h (28CY), the curd dry matter (CDM) and the ratios between ThCY and real yields (FCY, 28CY and CDM). Compared to the less productive subjects, despite similar percentage of proteins, the more productive subjects had a higher percentage of casein (3.73 vs. 3.64; P < 0.05), a greater incidence of the latter on total protein (80.52 vs. 79.60; P < 0.05), higher content in lactose (4.88 vs. 4.81; P < 0.01) and urea (42.44 vs. 40.48; P < 0.05) and a lower BCS value (6.79 vs. 7.25; P < 0.05). These differences are not always confirmed in both farms. Regardless of the production level, subjects of farm S.A. had a lower production/lactation (2524 vs. 2817 kg; P < 0.01), higher values of R and k20 (P < 0.01), lower value of a30, a higher SH value and lower contents in urea and solid not fat. They also showed a lower ThCY yield and a lower ratio between ThCY and 28CY when proteins were corrected for the urea content, and a higher ratio between 28CY and the percentage of proteins, both when corrected or not for the urea content. It is difficult to explain the influence of the production level on the casein content whereas the greater lactose content in more productive buffaloes may be accounted for by the greater persistence of lactation curve. The higher urea content found in buffaloes with a greater galactopoietic attitude may be due to a greater DM intake caused by the inadequacy of the diet, hypothesis confirmed by the lower BCS observed in the more productive subjects.

Modelling of pH, dry matter and mineral content of curds during soft cheese drainage

The influence of the temperature at the rennet addition (31.2, 32.0 and 32.8 °C) and of the starter type on the soft cheese drainage process was studied. Off-line measurements of pH, cal- cium and phosphorous concentrations, as well as dry matter of the curd were performed in parallel with on-line measurements of the weight and pH of the whey. Only the starter type was found to have a significant influence on the curd and whey pH, on the calcium concentration in the curd and on the calcium/dry matter ratio. Correlations were established between weight of the whey and dry matter of the curd, as well as between pH of the whey and physico-chemical measurements in the curd. Linear regressions gave satisfactory results only when performed separately for each type of starter. Artificial neural networks allowed the building of common models for both starters and pre- dicting curd pH, calcium concentration and the calcium/dry matter ratio using the pH of the whey at one hour after moulding. Drainage / curd characteristics / pH / starter / on-line measurement / modelling

Survival of Listeria monocytogenes during manufacture, ripening and storage of soft lactic cheese made from raw goat milk

Soft lactic cheeses were manufactured with raw goat milk inoculated with Listeria monocytogenes. The physico-chemical and microbiological characteristics of curds and cheeses were determined after each processing step as well as during ripening and refrigerated storage. The fate of Listeria monocytogenes was evaluated by enumeration on PALCAM agar and by a qualitative detection after a double selective enrichment procedure. The results showed that the physico-chemical and microbiological characteristics of lactic cheeses caused a decrease of Listeria monocytogenes counts. However, this decrease did not lead to the complete disappearance of the pathogen and Listeria monocytogenes was able to survive in soft lactic cheeses made with raw goat milk

Residual amount of water in a draining curd of camembert cheese and physicochemical characteristics of the drained curd as modified by the pH at renneting, the casein concentration and the ionic strength of milk

Camembert soft cheeses were prepared from cheese milk modified using membrane tech- nologies to obtain different casein contents (27-37 g.kg -1 ) and different ionic strengths estimated from the dilution factor of milk with a lactose solution (0.6 compared to 1.0 in normal milk). Renneting was performed at pH 6.0 or 6.4. The amount of water remaining in the draining curds, expressed as the water to casein ratio, R (g .g -1 ), was calculated from the whey drainage kinetics data. A kinetics of variation of R during drainage was obtained in each of the experimental conditions and was characterised by fitting with a descriptive mathematical model involving 2 relaxation processes and 5 parameters: R (g water.g -1 casein) = R1 exp(-t/τ1) + R2 exp(-t/τ2) + R3. The R values at the end of drainage, obtained from the model for t = 1 000 min, fitted well with the water amounts determined in the drained curds by chemical analysis. The values of the equation parameters, obtained by fitting the equa- tion to experimental data, were correlated to the levels of factors which were varied in the experiments. This allowed a mean value for each parameter to be obtained, and values for the effects of factors. The amount of water remaining in drained curd at the end of drainage was dependent on the milk casein content and pH at renneting factors through a negative effect. Prediction of final values of R by cal- culation from this data was possible. However, the correlation with experimental values was low. In addition, the drained curd composition and rheological properties were determined and the effects of the factors on these curd characteristics were quantified. A positive effect of the pH at renneting on the dry matter and ash contents of drained curd was observed. Incidentally, these factors also mod- ified its rheological properties.