Sheep Milk Cheese Research Articles

Investigation of some probiotic and technological properties of lactic acid bacteria strains isolated from artisanal sheep milk cheese and their growth in goat milk

The objective of this study was to assess the probiotic and technological properties of lactic acid bacteria (LAB) isolated from artisanal sheep milk cheeses for potential use in dairy products made from goat milk. Strains studied were Lacticaseibacillus paracasei LC6, Lactiplantibacillus plantarum LP48, Lactococcus lactis subsp. hordniae LH69 and Leuconostoc mesenteroides LM99. The criteria studied were fermentative capacity, carbohydrate fermentation profile, β-galactosidase (lactase) activity, auto-aggregation capacity, hydrophobicity, antimicrobial activity, resistance to simulated gastric secretion, bile resistance, and resistance to different pH and salts concentrations, as well as growth and viability in goat milk. In general, the strains studied showed characteristics compatible with potential probiotic effects. However, according to criteria studied, L. plantarum LP498 best met the conditions; it was compatible with probiotic potential under all the conditions considered and showed noteworthy differences compared to the other micro-organisms studied, particularly in its capacity for self-aggregation and pH resistance. Therefore, L. plantarum LP48 could be adequate for the manufacture of artisanal goat milk products.

Description of “Ovino Belmontese”, a new semisoft sheep's milk cheese processed using “Italico” cheese technology

The objective of this study was to create a new semisoft sheep's milk cheese called “Ovino Belmontese” cheese (OBCh) by applying the “Italico” cheese-making technology. The cheese production took place under industrial conditions, with the addition of a commercial starter formulation containing Streptococcus thermophilus. The microbiological, physicochemical, and sensory characteristics of OBCh were assessed and compared to those of a commercially available cow's Italico cheese (CICh). Streptococcus thermophilus dominated the microbial community during the cheese-making process, reaching levels of approximately 9.0 Log CFU/g in both OBCh and CICh. Among physical characteristics, no statistically significant difference (p ≥ 0.05) was registered in terms of lightness, redness, yellowness, and hardness between the two cheeses. OBCh exhibited a twofold higher short-chain fatty acid content compared to CICh. Both cheeses displayed similar classes of volatile organic compounds, although their relative percentages differed. The application of Italico cheese technology to process sheep's milk did not negatively affect sensory attributes. This study highlighted that utilizing a cheese-making technology not commonly used for processing sheep's milk represents a promising strategy to diversify Sicilian dairy productions.

Artichoke extract and human bifidobacteria to attain symbiotic sheep milk cheeses

There is a growing interest for healthy non-bovine functional dairy products. Therefore, in the present study, an aqueous polyphenol-rich artichoke extract (AE) and two Bifidobacterium strains of human origin (B. pseudolongum INIA P2 and B. longum INIA P132) were added, alone or in combination with AE, for the manufacture of six sheep milk cheeses. In general, addition of 1.25 g of lyophilized AE per 100 g of curd did not affect cheese pH, dry matter, lactoccci starter counts or organic acid levels during ripening. Bifidobacterial strains showed good viability in cheeses with AE during ripening and after simulated major gastrointestinal conditions. Cheeses with AE showed improved functional properties, with significantly (P < 0.01) higher total polyphenol content and, especially, antioxidant activity The cheese with AE and strain INIA P2 fulfil the definition of a symbiotic cheese. It contains prebiotic compounds and Bifidobacterium at adequate levels to sustain a therapeutic effect, which are able to survive major gastrointestinal conditions. This cheese could confer beneficial effects on consumers’ health by contributing to the host antioxidant capacity and increasing polyphenol bioavailability.

Influence of Salting and Ripening Conditions on the Characteristics of a Reduced-Fat, Semi-Hard, Sheep Milk Cheese.

This study aimed to assess the effect of salting and ripening conditions on the features of sheep milk, reduced-fat, semi-hard cheese. Eight groups of cheese, with an average fat content of ≅10.5%, moisture on non-fat substances (MNFS) ≅ 56%, a protein-to-fat ratio of 2.9 and pH 5.1, were manufactured and analyzed throughout ripening. The experimental factors were the salting method (brine- or dry-salting), the salt content (control- and reduced-salt) and the ripening temperature sequence (11 or 18 °C at the 3rd and 4th week). Brine-salted cheese exhibited significantly more adequate (p < 0.05) textural and organoleptic characteristics compared to its dry-salted counterpart, i.e., lower hardness, gumminess and adhesiveness, with higher lightness and flavor scores. The mean salt reduction from 2.1 to 1.6% exhibited significant effects (p < 0.05), i.e., increased moisture and MNFS, decreased hardness, gumminess, chewiness and adhesiveness, and increased lightness and meltability of cheese without affecting the microbiological stability or impairing the organoleptic parameters. Ripening at 18 °C at weeks 3-4 significantly increased (p < 0.05) proteolysis and concentrations of lactic and citric acid without affecting meltability, textural or organoleptic features. In conclusion, brine-salting, salt reduction by 20% and the elevation of temperature at a particular ripening period improved the characteristics of this type of reduced-fat sheep milk cheese.

Production and Evaluation of Soft Sheep's Milk Cheese Analogues Supplemented With Quinoa Seed Flour and Xanthan Gum

Production and Evaluation of Soft Sheep's Milk Cheese Analogues Supplemented With Quinoa Seed Flour and Xanthan Gum

Ecolabelling for improving sustainability of agri-food supply chain: An experimental implementation of the Made Green in Italy scheme on the hard sheep milk cheese

Unsustainable food supply chains are sources of relevant environmental impacts and strongly contribute to the depletion of non-renewable resources. Ecolabelling is one of the measures for increasing market awareness of the sustainability of a product and encourage the implementation of low-input practices along the food production system. Made Green in Italy (MGI) scheme is an initiative based on the PEF method and aimed to reward Made in Italy products with high environmental profile. A screening study was conducted on four Sardinian dairy plants to develop an experimental MGI application on the hard sheep milk cheese supply chain, using Pecorino Romano PDO as reference product. Sheep milk phase resulted the main contributor for all relevant impact categories (over 94%). Benchmark score (1.33E-05 Pt) was calculated adding the normalized and weighted values of the 3 main relevant impact categories (Climate Change, Land Use and Water Scarcity). Three performance classes were defined considering the best and the worst values of life cycle processes: upper threshold was equal to 1.62E-05 Pt and lower threshold was equal to 1.17E-05 Pt. The relevant sheep milk impact highlighted the crucial role of sheep farming systems for improving the environmental footprint of the Pecorino Romano PDO.

Occurrence and molecular surveillance of pathogenesis risk-associated factors in Staphylococcus aureus recovered from raw sheep's milk cheese

The aims of our study were to ascertain the presence of different accessory gene regulator (agr) groups, to monitor the occurrence of 12 biofilm- and 5 enterotoxin- related genes and moreover to explore the biofilm-forming ability and antibiotic susceptibility in Staphylococcus aureus isolated from raw sheep’s cheese.From 92 samples of raw sheep’s cheeses, 32% (29 cheeses) harboured Staphylococcus aureus; among those 89.6% were biofilm producers, 55% had enterotoxigenic potential and 17.2% were phenotypically resistant to oxacillin. Five oxacillin resistant isolates were positive for blaZ and were classified into 5 different spa types (t179, t216, t1773, t12029, t13487). In the present study, 79% of Staphylococcus aureus isolates were agrI or agrII-positive. Four biofilm-associated genes (clfA, cna, bbp and fnbpA) were detected only in agr-positive strains.

Changes in physicochemical, microbiological and fatty acid composition during the ripening period of artisan sheep cheese from Bulgaria

The composition of artisan sheep's milk cheese during the ripening period was studied. The raw material used for cheese production, was obtained from an indigenous Karakachan sheep from Bulgaria. It was found that the main physicochemical parameters of the cheese have changed during the study period. During the ripening process, chaaracteristics such as dry matter, total protein and fat content increased by approximately 7.0%, 3.0% and 4.0% respectively, while the water content of the samples decreased by up to 7.0%. A smooth acidification process was observed, which correlated with the high number of lactic acid bacteria. The fatty acid analysis showed that the saturated fatty acid composition was 66.0% and unsaturated fatty acids were 34.0%. During the biochemical ripening at the 60th day of the test period, the presence of linoleic polyunsaturated fatty acid was found to be 0.12%.

Comparison of Activity of Commercial Protective Cultures and Thermophilic Lactic Acid Bacteria against Listeria monocytogenes: A New Perspective to Improve the Safety of Sardinian PDO Cheeses.

Listeria monocytogenes contamination that occurs during and post-processing of dairy products is a serious concern for consumers, and bioprotective cultures can be applied to control the growth of the pathogen in sheep milk cheeses. However, to respect specifications provided for protected designation of origin (PDO) cheeses, only autochthonous microorganisms can be used as bioprotective cultures in these products. This in vitro study aimed to evaluate thermophilic lactic acid bacteria (LAB) isolated from sheep milk as bio-preservative agents to control L. monocytogenes growth in PDO cheese. Results were compared with those obtained with a commercial protective culture (cPC) composed of a Lactiplantibacillus plantarum bacteriocin producer designed to inhibit L. monocytogenes growth in cheese. The in vitro antilisterial activities of n.74 autochthonous LAB and a cPC were tested against 51 L. monocytogenes strains using an agar well diffusion assay. In addition, 16S rRNA sequencing of LAB isolates with antilisterial activity was conducted and strains of Lactobacillus helveticus, Lactobacillus delbrueckii subsp. indicus, Lactobacillus delbrueckii subsp. sunkii, Lactobacillus delbrueckii subsp. lactis and Enterococcus faecalis were identified. In this study, 33.6% (74/220) bacterial strains isolated from milk had characteristics compatible with thermophilic LAB, of which 17.6% (13/74) had in vitro antilisterial activity. These results demonstrate that raw sheep milk can be considered an important source of autochthonous thermophilic LAB that can be employed as protective cultures during the manufacturing of Sardinian PDO cheeses to improve their food safety. The use of bioprotective cultures should be seen as an additional procedure useful to improve cheese safety along with the correct application of good hygienic practices during manufacturing and the post-processing stages.

Use of commercial protective cultures in portioned sheep milk cheeses to control Listeria monocytogenes.

The main objective of this study was to innovate soft and semi-cooked sheep milk cheese production processes with the use of a commercial protective culture able to control Listeria monocytogenes growth. A freeze-dried commercial culture of Lactobacillus plantarum was tested in DS cheese and PS cheese, two types of pasteurized sheep milk, raw-paste cheeses aged for no less than 20 and 30 days respectively. In the first step, in vitro tests were conducted to identify the most suitable matrix for the growth of L. plantarum in order to create a subculture that could be used at industrial cheese-making plants. During the second phase of the study, L. plantarum culture was introduced in the manufacturing process of the cheeses in a production plant. Finally, a challenge test was conducted on portioned DS and PS cheeses in order to evaluate the activity of the protective culture against L. monocytogenes: the cheeses were portioned, experimentally contaminated with L. monocytogenes strains, vacuum packed and stored at +4°C (correct storage conditions) and at +10°C (thermal abuse). Cheeses were analysed at the end of the shelf-life to evaluate the presence and growth of L. monocytogenes, to enumerate lactic acid bacteria and determine chemicalphysical features. The results confirmed that protective cultures are a useful technological innovation to control L. monocytogenes growth during cheese storage without altering composition, microflora and chemical- physical characteristics of the product. However, the use of protective cultures should be applied as an integration of risk control measures and not as a substitute for preventive actions.

The effect of seasonality on the biogenic amines, free amino acids, and physico-chemical composition of raw milk Fiore Sardo cheese produced in Sardinia (Italy)

The effect of seasonality on the content of biogenic amines (BA), compounds that could threaten food safety at a high level, were evaluated in Fiore Sardo, a typical artisanal raw sheep's milk cheese produced in Sardinia. The cheese samples collected from six farms, after four months of ripening, were manufactured from January to June. The relationship between the BA content, the free amino acid (FAA) concentration, and the physico-chemical composition (pH, a w , NaCl, humidity, and the fat and protein content) was considered. The FAA and BA contents were determined by HPLC-FL. The BA content and the other parameters analysed were significantly affected (p ≤ 0.000) by seasonality and the farm of origin. Despite the differences attributable to the producers, the seasonal variations of all the parameters considered followed the same trend. As the season changed, the level of total BA grew, reaching a mean content of 1402 ± 207 mg/kg in the samples produced in June, almost five times the mean value of those manufactured in January. The most represented biogenic amine was tyramine, followed by putrescine and cadaverine. Histamine was determined almost exclusively in some samples produced in the warmer months, while β-phenylethylamine and tryptamine were found in a low concentration or not detected. The winter products did not exceed the threshold of 900 mg/kg proposed for the total BA in food, while most of the samples manufactured in the hottest months exceeded this limit, posing a potential risk to consumers' health. The total FAA and BA content were correlated (p = 0.01), indicating that with the change of the season, proteolysis phenomena increased and made the precursor amino acids available for microbial decarboxylase activity. In addition, from January to June, the pH and fat levels grew, while those of a w , humidity and NaCl tended to decline. The study highlighted that as the season changed, the rise in temperature, probably combined with the increment of fat and decrement of NaCl content, could favour proteolysis phenomena and bacterial decarboxylase activity and, as a result, the escalation of BA production. Interventions in the production protocol to reduce the negative effect of seasonality on cheese safety are needed. In addition, in light of these results, it is possible to speculate that the rising temperature and the predicted lengthening of the warm season due to climate change, which also seems to affect the spring periods, could create the ideal conditions for the production of biogenic amines for an increasingly extended phase of the year.

Growth Kinetics of Bacteria Isolated from Laboratory Prepared Cheese Made From Different Milk Sources

Background: Dairy food products constitute a major part of our routine diets and it is fundamental to the food industry globally. However, the need for quality control cannot be over-emphasized. A microbiological guideline must be used to define the differences between unacceptable and acceptable food products as food-borne related diseases have been associated with milk and dairy products. Aim of Study: The study aims to evaluate the growth kinetics of cheese prepared in the laboratory from different milk types over a 96 hour period in order to determine its bacteriological quality and assess the effect of storage time on the pH of the various cheeses. Methods: The laboratory cheese was prepared from fresh Goat, cow, sheep and soybeans using the traditional method. Thereafter, 10g of the cheese samples were stored in sterile 250 ml conical flasks at temperature of 28±2 oC for duration of 96 h. The samples were analyzed every 12-24 h interval using Nutrient Agar, MacConkey Agar, Mannitol Salt Agar and De Mann Rogosa and Sharpe Agar for their bacterial, coliform, staphylococcal and lactobacilli load respectively. Results: At 96 h the highest heterotrophic bacterial load, coliform, staphylococcal and lactic acid bacteria counts were observed in sheep milk cheese (8.27 ± 0.02 Log10cfu/g), (7.10 ± 0.33 Log10cfu/g), (7.40 ± 0.34 Log10cfu/g) and cow milk cheese (8.19 ± 0.05 Log10cfu/g) respectively. At 0 h the highest pH was recorded in Soybean milk cheese (5.76±0.01) while the least was cow milk cheese (4.97±0.11). The highest pH at 96 h was Soybean milk cheese (6.96±0.01) while the least pH was recorded in sheep milk cheese (6.12±0.00). Comparing results of this present study with that of the European Union microbiological regulations (EUMR) and the Gulf Standards Organization (GSO) for foods, the bacteria load of all cheese samples at 12 h was within the acceptable or permissible limit. Conclusion: The present study indicates that laboratory prepared cheese contains a repertoire of significant public health microorganisms in numbers above the permissible limit. It is recommended that appropriate aseptic procedures should be strictly upheld by dairy handlers across the entire chess production value chain.

Optimization of Modified Atmosphere Packaging for Sheep’s Milk Semi-Hard Cheese Wedges during Refrigerated Storage: Physicochemical and Sensory Properties

Modified atmosphere packaging (MAP) has become a good potential strategy to retain quality throughout the shelf life of perishable foods. The aim of this work was to evaluate different packaging atmospheres on semi-hard protected designation of origin Idiazabal cheese wedges. Six different packaging treatments (air, vacuum, and CO2/N2 gas mixtures in the ratio of 20/80, 50/50, 80/20, and 100/0% v/v, respectively) were studied. Changes in gas headspace composition, cheese gross composition, weight loss, pH, acidity, colour, and textural and sensory properties were investigated during 56 days of refrigerated storage at 5 ± 1 °C. MAP was the most effective preserving technique compared to air- and vacuum-packaging treatments. The cheese characteristics with the greatest discriminating weight in the preservation techniques were paste appearance, holes, flavour, a* (redness) and b* (yellowness) colour parameters, and slope to hardness. Air-packaged cheeses, on 35 day, presented a mouldy flavour. Vacuum packaging affected paste appearance (greasy, plastic marks, and non-homogeneous colour) and holes (occluded and unnatural appearance) starting after 14 packaging days. MAP mixtures with CO2 concentration between 50/50 and 80/20% CO2/N2 (v/v) are recommended to ensure sensory quality and stability in the distribution of these raw sheep-milk cheese wedges.

Relationship between Volatile Organic Compounds and Microorganisms Isolated from Raw Sheep Milk Cheeses Determined by Sanger Sequencing and GC-IMS.

Recently, the interest of consumers regarding artisan cheeses worldwide has increased. The ability of different autochthonous and characterized lactic acid bacteria (LAB) to produce aromas and the identification of the volatile organic compounds (VOCs) responsible for flavor in cheeses are important aspects to consider when selecting strains with optimal aromatic properties, resulting in the diversification of cheese products. The objective of this work is to determine the relationship between VOCs and microorganisms isolated (Lacticaseibacillus paracasei, Lactiplantibacillus plantarum, Leuconostoc mesenteroides and Lactococcus lactis subsp. hordniae) from raw sheep milk cheeses (matured and creamy natural) using accuracy and alternative methods. On combining Sanger sequencing for LAB identification with Gas Chromatography coupled to Ion Mobility Spectrometry (GC−IMS) to determinate VOCs, we describe cheeses and differentiate the potential role of each microorganism in their volatilome. The contribution of each LAB can be described according to their different VOC profile. Differences between LAB behavior in each cheese are shown, especially between LAB involved in creamy cheeses. Only L. lactis subsp. hordniae and L. mesenteroides show the same VOC profile in de Man Rogosa and Sharpe (MRS) cultures, but for different cheeses, and show two differences in VOC production in skim milk cultures. The occurrence of Lactococcus lactis subsp. hordniae from cheese is reported for first time.

Infrared spectroscopy-based rapid determination of adulteration in commercial sheep's milk cheese via n-hexane and ethanolic extraction

This study aimed to authenticate a commercial cheese using FT-IR spectroscopy combined with chemometrics via ethanol and n-hexane extraction. Erzincan Tulum cheese (ETC) is one of the most produced and consumed cheeses in Türkiye. With an increase in production and consumption, adulteration has become a concern. Authentic ETC (n = 24) and non-authentic cheese samples (n = 22) were purchased from local markets. Ethanol and n-hexane extracts of the ETC were used for FT-IR analysis. Aliquots of the extracts were placed on a zinc selenide crystal, dried, and scanned in the mid-infrared region (4000–650 cm−1). Partial least squares-discriminant analysis (PLS-DA), soft independent modelling of class analogy (SIMCA), and conditional entropy (CE) were used as chemometric tools. PLS-DA and SIMCA provided 99% accuracy, followed by CE as low as 93.5%. Despite some disadvantages, overall, FT-IR spectroscopy with chemometrics is simple, rapid, and an inexpensive tool to detect cheese adulteration.

Proteolysis and lipolysis in Tulum cheeses ripened in plastic barrels and goat skin bags made using Penicillium roqueforti 41 strain

In this research, Tulum cheeses were manufactured from raw (R, RM, RT, and RMT samples) and pasteurized Akkaraman sheep milk cheeses (P and PM samples). Tulum cheeses were manufactured with Penicillium roqueforti 41 strain (RM, PM, RMT samples) and without mold strains (R, P, and RT samples). The cheeses were ripened in plastic barrels (R, RM, P, and PM samples) or goat skin bags (called tulum) (RT and RMT samples) for 120 days at + 4 °C. In the last two stages of the ripening period (60 d =90th and 90 d=120th), samples in plastic barrels and tulums were pierced using a needle to allow air entrance. Namely, in the last two stages of the ripening period, all cheese samples were drilled. The cheese was named 60 d = 90th day, which means that it was analyzed on the 90th day after the drilling (piercing) process on the 60th day, and 90 d = 120th day, which means that it was analyzed on the 120th day after the drilling process on the 90th day. The physical, chemical composition, lipolysis, and proteolysis levels of the RT and RMT samples were found to be higher than those of the R, RM, P, and PM samples. The inoculated mold strain (P. roqueforti 41) enhanced the proteolysis and lipolysis levels of the RM, PM, and RMT samples, especially after the piercing operation. Additionally, the inoculated P. roqueforti 41 strain increased the hydrolysis of hydrophobic peptides of RM, PM, and RMT samples depending on mold growth on the 60 d = 90th and 90 d = 120th days of ripening, in which a piercing operation was applied.

Life cycle assessment of sheep cheese production in a small dairy factory from Romanian rural area.

The paper aims to analyse the life cycle of sheep milk cheese production, to investigate supply chain of cheese and to suggest improvements for minimizing the environmental impacts associated with this agri-food product. The functional unit chosen was 1kg of sheep milk cheese. Modelling of the production process was performed based on real data obtained from a cheese production company in Romania. Two methods (CML and ReCiPe), included in GaBi software, were used for the environmental impact assessment. The following impacts: abiotic depletion potential elements, acidification potential, eutrophication potential, global warming potential, human toxicity potential (included in CML method) and climate change, fossil depletion, freshwater eutrophication, particulate matter formation, photochemical oxidant formation, terrestrial acidification (included in ReCiPe method), were calculated. Results highlighted that energy production and diesel consumption are the main activities which contribute to the environmental impacts associated with cheese product. Emissions from diesel production and consumption contribute to global warming potential with 11.70% and 82.36%, respectively. Wastewater treatment mainly contributes to freshwater eutrophication with 43.58%, followed by raw milk production (37.52%), diesel production (12.34%) and others. The results of this study showed that the values for most impact categories decrease when the energy is obtained by renewable sources compared to the energy produced by conventional procedures. It was concluded that, in order to reduce the environmental impacts associated with sheep cheese production, the energy used in the process needs to be more environmentally friendly.

Contribution of salt content to the ripening process of Croatian hard sheep milk cheese (Brač cheese)

Brač cheese is a traditional Croatian cheese manufactured from the raw sheep milk. The aim of the research was to estimate the contribution of initial salt in moisture content to the composition, proteolysis, and texture of Brač cheese during ripening. Higher initial salt in moisture content significantly (P < 0.05) induced higher moisture loss as well as significantly higher (P < 0.05) increase in fat and salt content in Brač cheese. The experimental group of cheeses with higher initial salt in moisture content (1.71–2.10%) had a significantly (P < 0.05) higher amount of intact α s1 -casein and a lower value of WSN %TN and TCA-SN %TN in relation to the other two groups (0.90–1.30% and 1.31–1.70%). In contrast, higher initial salt in moisture content in Brač cheese significantly (P < 0.05) stimulated hydrolysis of β-casein. The texture evaluation showed that the cheeses tended to become significantly (P < 0.05) harder and shorter as initial salt in moisture content increased. The principal component analysis showed primary contribution of moisture and salt in moisture content to the formation of harder and less fracturable cheese during ripening while formation of short textured Brač cheese was a consequence of an increase in the values of secondary proteolysis.

Microbial risk assessment of Escherichia coli shiga-toxin producers (STEC) in raw sheep's milk cheeses in Italy

Shiga toxin-producing E. coli (STEC), widespread pathogens associated with severe foodborne disease, can contaminate milk during the milking process through faecal matter and survive or grow during cheese making if a pasteurization treatment has not been applied. Thus, a stochastic “farm-to-fork” model was developed to assess the risk of human infection by O157 STEC, one of the main pathogenic serotypes, associated with the consumption of a portion of raw sheep's milk cheese produced in a farmhouse dairy in Italy. The average risk of illness after the consumption of a portion of brief-, medium- and long-ripened cheese ranged between 1.64 × 10−4 and 4.03 × 10−4 for adults. Considering only a difference in serving size, the risk for children varied from 1.35 × 10−4 to 3.34 × 10−4. Among the several intervention strategies simulated to mitigate the risk, administration of bacteriophages was, by far, the most effective measure with an average risk reduction of 34 times followed by use of probiotics and antimicrobials, which lowered the risk about 12 times. The sensitivity analysis showed that the probability that a shedder is present in the herd, the occurrence of the milk contamination with faeces and the within-herd prevalence of the pathogen were the parameters that most affected the risk. While further data is necessary to confirm the conclusion of this study, the model results might be able to assist producers and policymakers to manage the risk of STEC infection linked to such products.

Properties of Sweet Buttermilk Released from the Churning of Cream Separated from Sheep or Cow Milk or Sheep Cheese Whey: Effect of Heat Treatment and Storage of Cream.

The objective of the study was to compare the buttermilk released from the churning of sweet cream separated from sheep milk (BSM) or whey (BSW) with the buttermilk from sweet cow milk cream (BCM). Additional experimental factors were the heat treatment (68 °C for 10 or 30 min) and storage of cream (refrigeration or freezing). The composition of BSM was the most advantageous in terms of non-fat solids, protein—which was the most abundant solid component—casein, calcium and phosphorus contents. No significant differences were observed in the phospholipids (PL) content of BSM, BCM and BSW. Antioxidant potential and emulsion stability (ES) of BSM were the highest. The radical scavenging activity (RSA) of BSW was high opposite to chelating activity (CA). Some functional properties of BSW were similar to those of BSM and BCM. The freezing of cream affected the churning, the fat content, the soluble nitrogenous fraction at pH 4.6 (WSN) and some functional properties of buttermilk, but not in a consistent manner. The properties of BSM were marginally affected or unaffected by the use of frozen cream. The freezing of whey cream caused significant changes (p < 0.05) in the protein profile and the functional behaviour of BSW. Cream heat treatment affected the WSN of BSW opposite to its sweet cream counterparts.