Physicochemical analysis of full-fat, reduced-fat, and low-fat artisan-style goat cheese

The objective of this study was to examine the physicochemical properties of cheese elaborated via traditional artisan methods using goat milk containing 5, 1.5, or 0.4% fat and ripened for 1, 7, 14, or 28 d. Seventy-two cheeses were produced (2 batches × 3 fat levels × 4 ripening times × triplicate). Proximal composition, pH, texture analysis, and color were recorded in each cheese. Protein and moisture were increased in cheese, and fat and fat in DM were decreased with decreasing fat in milk. Internal and external pH was higher in low-fat and reduced-fat cheese, and pH values decreased during the first 2 wk of ripening but increased slightly on d 28. Cheese fracturability, cohesiveness, masticability, and hardness increased with decreasing fat, whereas elasticity and adhesiveness decreased. Cheese lightness and red and yellow indexes decreased with decreasing fat content; during ripening, lightness decreased further but yellow index increased.     

Detection of milk mixtures in Halloumi cheese

A capillary electrophoresis method has been applied to the detection of illegal addition of milk from goat and/ or cow in Halloumi cheese, traditionally made with sheep milk. The electrophoretic profiles of the casein from Halloumi cheeses have revealed that caprine para-kappa-casein and bovine alphas1-casein peaks point to the presence of low percentages of goat's and/or cow's milk added to Halloumi cheese. Stepwise multiple linear regression has been used to predict these percentages with a standard error of the estimation of 2.14%. The analytical method combined with the statistical application is valid for the prediction of percentages higher than 2% of goat's and percentages of 5% of cow's milk added to the cheese either in fresh or ripened cheese. The standard error of estimation was higher for the prediction of cow's milk than for goat's milk.     

The effect of aging on low-fat, reduced-fat, and full-fat Cheddar cheese texture

This study investigated the effects of aging and fat content on the texture of Cheddar cheese, both mechanical and sensory aspects, over a 9-mo aging period. Cheeses of 6, 16, and 33% fat were tested at 0.5, 3, 6, and 9 mo of aging. Cheeses were evaluated by a trained sensory panel using an established texture lexicon as well as instrumental methods, which were used to probe cheese structure. Sensory analysis showed that low-fat cheeses were differentiated from full-fat cheeses by being more springy and firm and this difference widened as the cheeses aged. In addition, full-fat cheeses broke down more during chewing than the lower fat cheeses and the degree of breakdown increased with aging. Mechanical properties were divided by magnitude of deformation during the test and separated into 3 ranges: the linear viscoelastic region, the nonlinear region, and fracture point. These regions represent a stress/strain response from low to high magnitude, respectively. Strong relationships between sensory terms and rheological properties determined in the linear (maximum compliance) and nonlinear (critical stress and strain and a nonlinear shape factor) regions were revealed. Some correlations were seen with fracture values, but these were not as high as terms related to the nonlinear region of the cheeses. The correlations pointed to strain-weakening behavior being the critical mechanical property. This was associated with higher fat content cheeses breaking down more as strain increased up to fracture. Increased strain weakening associated with an increase in fat content was attributed to fat producing weak points in the protein network, which became initiation sites for fracture within the structure. This suggests that fat replacers need to serve this functional role.     

牛羊乳的比例对Halloumi干酪得率及品质的影响

探究部分牛乳替代羊乳时Halloumi干酪的产率和品质。结果表明:提高原料乳中羊乳的体积比时,Halloumi干酪的产率、蛋白含量也显著提高,当牛羊乳的体积比为0∶1和1∶1时,产率分别高达12.03%和11.99%,两者差异性不显著(P>0.05);且羊乳的比率越高,Halloumi的硬度和咀嚼性显著越强(P<0.05),但弹性和凝聚性差异性不显著(P>0.05);但牛羊乳体积比1∶1的Halloumi干酪在气味和质地方面的得分显著高于牛羊乳的体积比为0∶1综合各项品质指标,最终确定牛羊比最佳配体积比为1∶1。     

Detection of milk powder and caseinates in Halloumi cheese

Halloumi cheese is traditionally manufactured from fresh milk. Nevertheless, dried dairy ingredients are sometimes illegally added to increase cheese yield. Lysinoalanine and furosine are newly formed molecules generated by heating and drying milk protein components. The levels of these molecular markers in the finished Halloumi have been investigated to verify their suitability to reveal the addition of skim milk powder and calcium caseinate to cheese milk. Because of the severe heating conditions applied in curd cooking, genuine Halloumi cheeses (n = 35), representative of the Cyprus production, were characterized by levels of lysinoalanine (mean value = 8.1 mg/100 g of protein) and furosine (mean value = 123 mg/100 g of protein) unusual for natural cheeses. Despite the variability of the values, a good correlation between the 2 parameters (R = 0.975) has been found in all cheeses, considering both the fresh and mature cheeses as well as those obtained from curd submitted to a prolonged cooking following a traditional practice adopted by a very small number of manufacturers. Experimental cheeses made by adding as low as 5% of skim milk powder, or calcium caseinate, or both, to cheese milk fell outside the prediction limits at ±2 standard deviation of the above-reported correlation regardless of curd cooking conditions or ripening length. This correlation may be adopted as a reliable index of Halloumi cheese genuineness.     

Physicochemical properties of low-fat and full-fat Cheddar cheeses

Low-fat (6% fat) and full-fat (32% fat) Cheddar cheese was manufactured and aged up to 6–9 months at 5°C. The objective was to study the impact of fat on the physicochemical properties of Cheddar cheese. Total soluble nitrogen (TSN) and protein nitrogen (TPSN) in aqueous extracts were determined by the Kjeldahl method. The peptide content of each cheese was determined with reverse phase chromatography (RPC). Low-fat Cheddar (LFC) had a markedly higher peptide content than full-fat Cheddar (FFC). The overall peptide quantity increased with age with a marked increase in hydrophobic peptide content. Rheological properties were determined using an Instron Universal Testing Machine. LFC had significantly higher stress values, indicating hard and rubbery texture, than FFC. Furthermore, LFC had lower strain values, indicating crumbliness.     

Changes of organic acids,volatile aroma compounds and sensory characteristics of Halloumi cheese kept in brine

This study examines the changes in organic acids, volatile aroma compounds and sensory characteristics of ovine Halloumi cheese kept in brine (∼10% NaCl) at 4 °C for 45 days. The highest total score of the organoleptic assessment was observed at day 1, before storage in brine. During cheese storage, a large reduction of lactose was observed, especially in the first stages of storage while, concurrently, a significantly progressive increase in lactic and acetic acids was observed. Among the volatile aroma compounds determined were alcohols, aldehydes, ketones, acids, esters, hydrocarbons, sulphur compounds, as well as a variety of other compounds in very small quantities. Ethanol and acetic acid were the dominant volatile aromatic compounds and their concentrations increased during storage. The lipolysis of Halloumi cheese during storage was not excessive. The dominant free fatty acids were palmitic, oleic and acetic.     

Changes during ripening in chemical composition,proteolysis, volatile composition and texture in Kashar cheese made using raw bovine,ovine or caprine milk

Kashar cheeses were manufactured from pure ovine (OV), bovine (BV) and caprine (CP) milk, and the chemical composition, cheese yield, proteolysis, hardness, meltability and volatile composition were studied during 90 days. Gross chemical composition, cheese yield and level of proteolysis were higher in OV cheeses than those of BV or CP cheeses. Glu, Val, Leu, Phe and Lys were the most abundant free amino acids (FAA) in the samples, and the concentrations of individual FAA were at the highest levels in OV cheeses with following BV and CP cheeses. Urea‐PAGE patterns and RP‐HPLC peptide profiles of the BV cheeses were completely different from the small ruminants’ milk cheeses (OV or CP). Higher and lower hardness and meltability values were observed in CP cheeses, respectively. OV cheeses resulted in higher levels of the major volatile compounds. In conclusion, the Kashar cheese made using OV milk can be recommended due to high meltability, proteolysis and volatiles.     

Possible implications of milk pasteurization on the manufacture and sensory quality of ripened cheese

Cheese made from raw milk represents an important proportion of the traditional cheeses, particularly in South European countries. Besides destruction of pathogenic bacteria, the most significant changes in milk relevant to cheesemaking, which are induced by pasteurization are:

• a partial elimination of the milk microorganisms which may grow in cheese during ripening,

• a partial or total activation or inhibition of the plasmin/plasminogen complex, cathepsin D, lipoprotein lipase and alkaline phosphatase. Enzymes from psychrotrophic bacteria, acid phosphatase and xanthine oxidase, which may be active during ripening, withstand pasteurization.,

• a slight (7%) denaturation of serum proteins and little or no modification of the cheesemaking properties (coagulation, acidification by lactic acid bacteria).

From experimental work carried out on several cheese varieties, comparing pasteurized or microfiltered milk and raw milk cheeses, it was found that facultatively heterofermentative lactobacilli, Micrococcaceae, enterococci, and propionibacteria in Swiss-type cheese, are found at higher levels in raw milk cheese. The main biochemical modification of cheese during ripening concerns the nature and extent of proteolysis. Although there is no clear trend in the breakdown of _s1- and β-caseins, milk pasteurization leads to a significant decrease of the amount of small peptides and free amino acids and to different HPLC profiles. Experiments carried out with sensory analysis show that, in all cases, pasteurized or microfiltered milk cheeses have received lower flavour intensity scores than raw milk cheeses. From this review, it is concluded that the indigenous milk microflora, with its diversity of species and strains, appears to be mainly responsible of the specific sensory properties of raw milk cheeses.     

The effect of sodium chloride substitution with potassium chloride on texture profile and microstructure of Halloumi cheese

The effect of partial substitution of NaCl with KCl on texture profile and microstructure of Halloumi cheese was investigated. Four batches of Halloumi cheese were made and kept in 4 different brine solutions (18%, wt/wt), including A) NaCl only, B) 3NaCl:1KCl, C) 1NaCl:1KCl, and D) 1NaCl:3KCl and then stored at 4°C for 56 d. The texture profile was analyzed using an Instron universal machine, whereas an environmental scanning electron microscope was used to investigate the effect of NaCl substitution on the microstructure of cheeses. No significant difference was found in hardness, cohesiveness, adhesiveness, and gumminess among experimental cheeses at the same storage day. Hardness, cohesiveness, and gumminess decreased significantly during storage period with the same salt treatment, whereas adhesiveness significantly increased. Environmental scanning electron microscope micrographs showed a compact and closed texture for cheeses at the same storage period. The microstructure of all cheeses became more closed and compact with storage period. Calcium content negatively correlated with hardness and Na and K contents during storage with the same salt treatment.     

Major and trace elements in milk and Halloumi cheese as markers for authentication of goat feeding regimes and geographical origin

Sixty samples of milk, Halloumi cheese and local grazing plants (i.e. shrubs) were collected over a year from dairy farms located on three different locations of Cyprus. Major and trace elements were quantified using inductively coupled plasma–atomic emission spectroscopy (ICP‐AES). Milk and Halloumi cheese produced in different geographical locations presented significant differences in the concentration of some of the elements analysed. Principal component analysis showed grouping of samples according to the region of production for both milk and cheese samples. These findings show that the assay of elements can provide useful fingerprints for the characterisation of dairy products.     

The effect of direct acidification on the microbiological,physicochemical and sensory properties of probiotic Minas Frescal cheese

Minas Frescal cheeses produced with the addition of the probiotic culture Bifidobacterium Bb‐12 and without (C1) or with (C2) lactic acid were evaluated in relation to the microbiological, physicochemical and sensory properties. After 28 days of storage, the cheeses without lactic acid showed lower moisture and pH, in addition to higher acidity and syneresis. This behaviour influenced the texture profile of the cheeses, making them harder and chewier. The colour attributes L* and b* diminished during the storage. The majority of the consumers classified the cheeses as having good acceptability and they would buy this type of functional food.     

A comparison of the chemical,microbiological and sensory characteristics of bovine and ovine Halloumi cheese

Commercial samples of fresh and mature Halloumi cheeses made from ovine or bovine milk were studied in order to establish their chemical, microbiological and sensory characteristics. Significant differences were observed between the two types of Halloumi cheese both when fresh and mature. The free volatile fatty acid (FVFA) content of the cheeses increased with maturation from 483 to 1356 mg kg⁻¹ for the ovine product, but lower values (380–1248 mg kg⁻¹) were found in the bovine cheese. During maturation for 40 days, Enterococcus faecium, which dominated the microflora of fresh ovine cheese, was replaced by lactobacilli, including a new species, Lactobacillus cypricasei, which was not found in the bovine samples. Fewer than 100 cfu g⁻¹ lactic acid bacteria (LAB) were present in the fresh bovine cheeses, but a microflora dominated by lactobacilli developed with time. Yeast counts in the mature ovine and bovine cheeses reached 2.3–2.8×10⁵ cfu g⁻¹ and, as some of the yeasts were proteolytic and/or lipolytic, it was assumed that they were having a positive impact of the flavour of the cheeses. The sensory panel distinguished significant differences in texture and flavour between the fresh and mature samples of both ovine and bovine cheeses and, overall, there was a significant preference for the ovine brand.     

Influence of different exopolysaccharide-producing strains on the physicochemical, sensory and syneresis characteristics of reduced-fat stirred yoghurt

Reduced-fat stirred yoghurts were prepared by using ropy and nonropy exopolysaccharide (EPS)-producing strains or nonexopolysaccharide-producing strains. Yoghurts were evaluated for pH, titrable acidity, acetaldehyde, whey separation, viscosity, EPS concentration, sensory and microbiological analyses. Determinations of these parameters were made at 1, 7, 14 and 21 days of storage. Reduced-fat yoghurts made with EPS⁺ strains exhibited lower syneresis and acetaldehyde contents, but higher viscosity than those made with the EPS ⁻ strain. Physico-chemical results correlated with the sensory results in that panellists scored the EPS⁺ yoghurts as having an overall better mouthfeel, but a worse flavour than EPS ⁻ yoghurt.     

Yield and sensory properties of cheese made with milk from Holstein or Montbéliarde cows milked twice or once daily

The aim of this study was to evaluate the milk properties and the yield and sensory properties of Cantal cheese made with milk from Holstein or Montbéliarde cows milked once or twice daily. Sixty-four grazing cows [32 Holstein (H) and 32 Montbéliarde (M) cows] in the declining phase of lactation (157 d in milk) were allocated to 1 of 2 equivalent groups milked once daily (ODM) or twice daily (TDM) for 7 wk. The full-fat raw milk collected during 24 h from the 4 groups of cows (M-TDM, M-ODM, H-TDM, and H-ODM) was pooled and processed into Cantal cheese 4 times during the last 4 wk of the experimental period. In all, 16 cheeses were made (2 milking frequencies × 2 breeds × 4 replicates) and analyzed after a ripening period of 15 and 28 wk. The results showed that for both breeds, the pooled milk content of fat, whey protein, casein, total protein, and phosphorus as well as rennet clotting time and curd firming time were significantly higher with ODM cows, whereas the casein-to-total protein ratio was lower, and lactose, urea, calcium, and free fatty acids contents of milk remained unchanged. The acidification and draining kinetics of the cheese as well as cheese yields and the chemical and rheological properties of the ripened cheese were not significantly modified by milking frequency. For both breeds, the cheeses derived from ODM cows had a slightly yellower coloration but the other sensory attributes, except for pepper odor, were not significantly affected by milking frequency, thereby demonstrating that ODM does not have an adverse effect on the sensory properties of Cantal cheese. Compared with that of Holstein cows, milk from Montbéliarde cows resulted in a higher cheese yield (+1.250 kg/100 kg of milk) and ripened cheeses with lower pH, dry matter, calcium, sodium chloride, and water-soluble nitrogen concentrations. These cheeses had also a less firm and more elastic texture, a more acidic taste, and a yogurt/whey aroma.