Effects of Penicillium roqueforti and whey cheese on gross composition,microbiology and proteolysis of mould‐ripened Civil cheese during ripening

Four different types of mould‐ripened Civil cheese were manufactured. A defined (nontoxigenic) strain of a Penicillium roqueforti (SC 509) was used as the secondary starter with and without addition of the whey cheese (Lor); in parallel, secondary starter‐free counterparts were manufactured. Chemical composition, microbiology and proteolysis were studied during the ripening. The incorporation of whey cheese in the manufacture of mould‐ripened Civil cheese altered the gross composition and adversely affected proteolysis in the cheeses. The inoculated P. roqueforti moulds appeared to grow slowly on those cheeses, and little proteolysis was evident in all cheese treatments during the first 90 days of ripening. However, sharp increases in the soluble nitrogen fractions were observed in all cheeses after 90 days. Microbiological analysis showed that the microbial counts in the cheeses were at high levels at the beginning of ripening, while their counts decreased approximately 1–2 log cfu/g towards the end of ripening.     

Proteolytic properties of Turkish white‐brined cheese (Beyaz peynir) made by using wild‐type Lactococcal strains

The development of proteolysis in white‐brined Turkish cheese made by using wild strains of Lactococcus lactis subsp. lactis (namely MBLL9, MBLL23 and MBL27) was monitored for 90 days. Proteolysis in cheeses was investigated using urea‐PAGE gel electrophoresis of pH 4.6‐insoluble and RP‐HPLC of both 70% ethanol‐insoluble and 70% ethanol‐soluble nitrogen fractions. Results indicated that developments of proteolysis in the experimental cheeses were strain dependent. The degradation of casein fractions was more evident in the cheeses made using strain MBLL23. The lowest levels of proteolysis and development of acidity were obtained in the cheese made using strain MBLL9.     

The effect of varying casein/fat ratio on physicochemical and sensory qualities of Feta‐type cheese made using buffalo milk

The Feta‐type cheese was prepared with different casein/fat (C/F) ratios of buffalo milk using microbial rennet. The manufactured Feta cheeses were subjected to physicochemical and sensory quality at 15‐day interval up to 60 days of ripening. Sensory analysis discriminated the different level of C/F ratio of buffalo milk cheeses predominantly by age. There was no significant difference (P < 0.01) observed in cheese made from C/F ratio of 0.6–0.7 in terms of flavour. The titratable acidity (TA), soluble protein and free fatty acid appear to be age‐dependent and increased throughout the ripening in all experimental cheeses.     

Influence of the season on proteolysis and sensory characteristics of Idiazabal cheese

The present study examined the influence of the manufacturing time on proteolysis and sensory characteristics of Idiazabal cheese. Samples of Idiazabal cheeses made using traditional manufacturing methods at two different times of year were collected at a plant operating under the auspices of the Idiazabal Cheese Appellation of Origin. The cheeses were made in February and June, roughly the beginning and the end of the manufacturing season. Chemical analyses were performed on d 1, 90, and 180 of ripening and sensory analyses on d 90, 120, and 180 of ripening. Higher nitrogen fraction (soluble and nonprotein nitrogen) levels and free amino acid contents were observed in the cheeses manufactured during the month of June. Degradation of the alphas- and beta-caseins was also greater in the cheeses made at that time of year. The cheeses manufactured in February earned higher sensory analysis scores for characteristic odor and taste and higher total sensory scores. The cheeses manufactured in June earned higher scores for the sensory attributes sweet flavor and bitter taste.     

Influence of rennet milk-clotting activity on the proteolytic and sensory characteristics of an ovine cheese

Roncal cheese (regulated by an Apellation of Origin) is a traditional hard cheese manufactured from raw ewe's milk in the region of Navarre in Spain. Roncal cheeses, manufactured using two lamb rennets with different milk-clotting activity levels, were evaluated to compare their chemical, proteolytic, and sensory characteristics. A preliminary study of samples of lamb rennets indicated that a large proportion of such rennets did not fulfil current microbiological requirements and likewise revealed considerable variation in the milk-clotting activity of the samples examined. Trends in the overall physicochemical parameter values (pH, dry matter, fat, and protein) were similar in both cheese batches. Proteolysis of the nitrogen fractions was observed to take place at a faster rate in the cheeses made using the rennet with the higher milk-clotting activity (soluble nitrogen, non-protein nitrogen, and amino acid nitrogen values around 13–20% higher than in the cheeses made using the rennet with the lower milk-clotting activity after 180 days of ripening). Urea-PAGE electrophoretic analysis of the caseins from the cheeses manufactured using both types of rennet showed that the β-caseins were less susceptible to proteolysis than the α_s-caseins. The effect of the different milk-clotting activity levels was most pronounced on the α_s-caseins, in which the rennet with the higher milk-clotting activity gave higher breakdown. Nevertheless, the differences in the proteolysis rates did not yield any appreciable sensory differences.     

Effects of Starter Culture and Coagulating Enzymes on Viscoelastic Behavior and Melt of Mozzarella Cheese

ABSTRACT: Mozzarella cheeses were made with a single culture (SC) or a mixed culture (MC) using 1x or 6x of cheese coagulants chymosin or Cryphonectria parasitica (CP). Melt area increased only by approximately 80% in cheeses made with SC against 230% in the cheeses made with MC after 30 d of storage. Soluble nitrogen was also higher in MC cheeses as compared to SC cheeses. Both the elastic (G') and the viscous (G") modulus decreased with storage. Decrease in both moduli was greater in the MC cheeses at 6× enzyme level compared to SC cheeses at 1× enzyme level. The synergism between coagulating enzyme and starter culture was beneficial, which improved melt and flow of Mozzarella cheese and had profound effects on the viscoelastic properties of Mozzarella cheese.     

Substitution of natural whey starter by mixed strains of Lactobacillus helveticus in the production of Reggianito Argentino cheese

Reggianito Argentino cheeses were manufactured with mixed strains of Lactobacillus helveticus cultured in free viable bacteria whey. As controls, cheeses with natural whey starter were made. Gross composition of cheeses did not differ significantly. The number of total termophilic lactic acid bacteria at the end of ripening was near 10⁷ CFU/g, but when the strain Lh 209 was present in the mixture, this number was 10⁶ CFU/g. Soluble nitrogen at pH 4.6 did not differ between control and experimental cheeses, but soluble nitrogen in tricloroacetic acid 12% and phosphotungstic acid 2.5% showed significant differences at the end of ripening, being higher the values when the strain Lh 209 was present in the mixture. Electrophoretic profiles for control and experimental cheeses were very similar at 0, 90 and 180 days of ripening. An increase in the acid degree value of fat during ripening was noticeable indicating a lipolytic activity in the cheese matrix that was similar for the different strains mixtures. Results from sensory analysis did not show differences among the cheeses of these tests. Despite some differences in the production tricloroacetic and phosphotungstic acid soluble nitrogen were observed for mixtures in which Lh 209 was present, all cheeses were good quality Reggianito Argentino cheeses. These results open and interesting prospective for the use of selected strains culture in whey in substitution of natural whey.     

The determination of water‐soluble vitamins and in vitro digestibility of selected Czech cheeses

Water‐soluble vitamins, in vitro organic matter digestibility (OMD) and dry matter digestibility (DMD) values were determined in various different Czech cheeses. An HPLC method for the simultaneous determination of niacin, pantothenic acid and pyridoxine in cheese was established. Different hydrolysis conditions and enzymes were used to release these vitamins from their complex form. The cheeses contained on average 2.04 mg of niacin, 3.24 mg of pantothenic acid and 2.16 mg of pyridoxine per 100 g of fresh mass. An enzymatic method was applied for the evaluation of OMD and DMD in cheeses. In vitro digestibility values ranged from 83.29% to 99.99% for organic matter (OMD) and 83.33% to 99.87% for dry matter (DMD) after two different enzymatic digestions (pepsin, pancreatin). In addition, cheeses incubated with pepsin plus pancreatin, OMD and DMD were strongly digested (99.04–99.83%, 97.73–99.74%).     

Accelerated ripening of Ras cheese using cell free extract,freeze- and heat-shocked Leuconostoc spp. cultures

Ras cheese was manufactured with cell free extract, freeze- and heat-shocked cultures of Leuconostoc spp. to enhance flavour development and accelerated ripening. Cheese analysis (pH, acidity, dry matter, fat, protein, soluble nitrogen, volatile acidity, free fatty acids) were carried out for 3 months. No significant differents were observed between the experiment cheeses and control, however, the cheese flavour was enhanced in cheeses with addition of heat treated Leuconostoc cells. Bitter taste was decreased in all experimental cheeses.     

THE CONTRIBUTION OF HERBS TO THE ACCUMULATION OF HISTAMINE IN "OTLU" CHEESE

The aim of this study was to determine the effect of herbs and the use of raw milk on histamine accumulation in “Otlu” (Herby) cheese during ripening. Cow's milk was used for the cheese production. The milk was divided into two main groups: one was used raw and the other was pasteurized at 65C for 30 min. Each group was further divided into two subparts, one of which was used as control (without herbs), while 2% (w/v) of the herbs were added into the other to produce Herby cheese. All cheeses were ripened at 7C for 90 days. The cheese samples were analyzed in terms of histamine content, titratable acidity, dry matter, salt and degree of ripening on days 5, 30, 60 and 90. Total mesophilic aerobic bacteria (MAB) were also counted during ripening. The use of raw milk and the addition of herb both increased histamine formation in Otlu cheeses (P < 0.05). Moreover, higher water‐soluble nitrogen values, as degree of ripening, were obtained from both raw milk and herb‐added cheeses. The number of MAB was higher in raw cheeses (P < 0.05) and also herb‐added cheeses. The study suggests that the addition of herbs may facilitate histamine formation in Herby cheese.     

Influence of starters on chemical, biochemical, and sensory changes in Turkish White-brined cheese during ripening

Turkish White-brined cheese was manufactured using Lactococcus strains (Lactococcus lactis ssp. lactis NCDO763 plus L. lactis ssp. cremoris SK11 and L. lactis ssp. lactis UC317 plus L. lactis ssp. cremoris HP) or without a starter culture, and ripened for 90 d. It was found that the use of starters significantly influenced the physical, chemical, biochemical, and sensory properties of the cheeses. Chemical composition, pH, and sensory properties of cheeses made with starter were not affected by the different starter bacteria. The levels of soluble nitrogen fractions and urea-PAGE of the pH 4.6-insoluble fractions were found to be significantly different at various stages of ripening. Urea-PAGE patterns of the pH 4.6-insoluble fractions of the cheeses showed that considerable degradation of α_s1-casein occurred and that β-casein was more resistant to hydrolysis. The use of a starter culture significantly influenced the levels of 12% trichloroacetic acid-soluble nitrogen, 5% phosphotungstic acid-soluble nitrogen, free amino acids, total free fatty acids, and the peptide profiles (reverse phase-HPLC) of 70% (vol/vol) ethanol-soluble and insoluble fractions of the pH 4.6-soluble fraction of the cheeses. The levels of peptides in the cheeses increased during the ripening period. Principal component and hierarchical cluster analyses of electrophoretic and chromatographic results indicated that the cheeses were significantly different in terms of their peptide profiles and they were grouped based on the use and type of starter and stage of ripening. Levels of free amino acid in the cheeses differed; Leu, Glu, Phe, Lys, and Val were the most abundant amino acids. Nitrogen fractions, total free amino acids, total free fatty acids, and the levels of peptides resolved by reverse phase-HPLC increased during ripening. No significant differences were found between the sensory properties of cheeses made using a starter, but the cheese made without starter received lower scores than the cheeses made using a starter. It was found that the cheese made with strains NCDO763 plus SK11 had the best quality during ripening. It was concluded that the use of different starter bacteria caused significant differences in the quality of the cheese, and that each starter culture contributed to proteolysis to a different degree.     

Proteolysis texture and microstructure of low‐fat Tulum cheese affected by exopolysaccharide‐producing cultures during ripening

The objective of the study was to determine the effects of exopolysaccharide (EPS)‐producing or non‐EPS‐producing starters on proteolysis, physical and microstructural characteristics of full‐fat or low‐fat Tulum cheeses during ripening. For this purpose, Tulum cheese was manufactured using full‐ or low‐fat milk with EPS‐producing and non‐EPS‐producing starter cultures. Chemical composition, proteolysis, texture profiles and microstructure of the cheeses were studied during 90 days of ripening. Urea‐PAGE of water‐insoluble and RP‐HPLC peptide profiles of water‐soluble fractions of the cheeses showed that the use of starters resulted in different degradation patterns in all cheeses during ripening. Although β‐casein exhibited similar degradation patterns in all cheeses, small differences are present in α_s1‐casein degradation during ripening. Reducing fat in Tulum cheese changed the RP‐HPLC peptide profile of the cheeses. The use of EPS‐producing cultures improved the textural characteristics and changed the microstructure and proteolysis of low‐fat Tulum cheese.     

Characterisation of aroma‐active compounds,chemical and sensory properties of acid‐coagulated cheese: Circassian cheese

The objectives of this study were to determine basic composition, aroma and sensory characteristics of Circassian cheese. Seven Circassian cheeses were provided by local producers. Aroma compounds were extracted by using solid‐phase microextraction procedure and determined by gas chromatography‐olfactometry system. Water‐soluble, trichloroacetic acid‐soluble and phosphotungstic acid‐soluble nitrogen fractions ranged between 2.30–29.35%, 2.48–9.96% and 3.33–6.26%, respectively. Diacetyl, butyric acid, 2‐acetyl‐1‐pyrroline, 1‐octen‐3‐one and methional were identified at high intensities in cheeses. In addition, ‘cooked’, ‘whey’, ‘creamy’ and ‘fermented’ were defined as characteristic flavour terms for Circassian cheeses.     

EFFECT OF HEATING AT DIFFERENT TEMPERATURES TO EXTEND THE SHELF LIFE OF VACUUM-PACKED WHITE CHEESE

The aim of this study was to determine the effects of heating applications on the shelf life of vacuum‐packed white cheese. Shelf life was evaluated for chemical, microbiological and organoleptic properties during the ripening period of 90 days. For this purpose, pickled white cheeses made with commercial starter cultures (Chr. Hansen R707 Lactococcus lactis subsp. lactis, L. lactis subsp. cremoris) were put in polyamide bags for vacuum packaging. During the ripening period, a water bath was used for heating applications at 65, 70 and 72C for 15, 10 and 5 min, respectively. In the ripening period, there were no changes in the values of dry matter in the control group. Dry matter values in control cheese were 40.02–42.09% (average value: 40.87%). Total acidity, protein (%), soluble nitrogen, ripening index (RI), tyrosine content and volatile fatty acid values all showed significant increases between the first and 90th days of the ripening period. However, in the heated cheese groups, dry matter showed no changes, but compared with the control group cheese total acidity, protein (%), soluble nitrogen, RI, tyrosine content and volatile fatty acid values increased but not as much as the control group.     

Coalho Cheese Made with Protease from Thermomucor indicae‐seudaticae N31: Technological Potential of the New Coagulant for the Production of High‐Cooked Cheese

The aim of this study was to explore the use of a new coagulant from Thermomucor indicae‐seudaticae N31 for the manufacture of a high‐cooked starter‐free cheese variety, by evaluating its physicochemical and functional characteristics in comparison to cheeses made with a traditional commercial coagulant. Coalho cheese was successfully produced with the new protease as it exhibited comparable characteristics to the one produced using the commercial enzyme: pH behavior during manufacture; cheese composition; protein and fat recovery; and cheese yield. In addition, during storage, melting was low and not affected by storage time; the increase of TCA 12% soluble nitrogen (% of total nitrogen) was lower than half of that of pH 4.6 soluble nitrogen (% of total nitrogen); concentration of β‐CN significantly decreased, whereas α_s1‐CN concentration was not affected by storage time.     

Volatile compounds and proteolysis in traditional Beaten (Bieno sirenje) ewe's milk cheese

Beaten ewe's milk cheese is a traditional autochthonous type of cheese manufactured in Macedonia with a relatively high nutritional value and sensory characteristics. The objective of this study was to characterise the gross composition, proteolysis and volatile profiles of the cheese that is supplied from different retails. The ranges for gross composition were from 31.53% to 42.83% (w/w) for moisture, 41.99% to 50.98% (w/w) for fat‐in‐dry matter, 2.03% to 8.25% (w/w) for salt content and 20.74% to 33.35% (w/w) for protein. Proteolysis results showed various levels of soluble nitrogen ranged from 3.15 to 33.50 for water‐soluble nitrogen (WSN) and from 1.11% to 6.79% for nitrogen soluble in 12% trichloroacetic acid (TCA‐SN). The ranges for total free amino acids were from 1.65 to 8.06 mg Leu/g. Lower proteolysis was observed in the cheese samples due to high salt contents. In total, 65 volatile compounds were identified in Beaten cheese. As a conclusion, the variation of the peptide profile, electrophoresis and volatile contents of Beaten cheeses are due to the lack of standardised manufacture protocols.     

Effect of starter cultures on the physico‐chemical and biochemical features in ewe cheese made with extracts from flowers of Cynara cardunculus L

The effect of starter cultures on the physico‐chemical and biochemical features of Los Pedroches cheese made by using Cynara Cardunculus L extracts as vegetable coagulant was assessed. Specimens of cheese containing no starter (vats A and C) and others to which a lactic acid starter was added (vats B and D) were stored either under typical farmhouse ripening conditions (vats A and B) or in a controlled chamber at 14°C and 80% relative humidity (vats C and D) for 90 days. The addition of starter cultures and the ripening conditions where found to have no appreciable effect on the moisture, fat, protein, ash, NaCl, Ca and P contents of the cheese, nor on its water activity; however, it resulted in increased lactic acid contents and lower pH values relative to control specimens throughout ripening. The protein breakdown of the cheeses was assessed in terms of soluble nitrogen, non‐protein nitrogen, aminoacid nitrogen, ammonia nitrogen, soluble tyrosine and tryptophan, and urea‐PAGE. Proteolysis was generally more marked and rapid in cheese containing the lactic starter, the NPN, NH₃ ‐N and soluble Tyr and Trp contents of which were significantly higher than those of the cheese obtained with no starter. The PAGE technique revealed no appreciable differences between the four cheese batches studied; however, it showed the cheese to be more resistant to β‐CN hydrolysis than to α_s‐CN hydrolysis. In general, the flavour and aroma scores were higher in batches obtained with starter cultures and ripened under controlled conditions. © 1999 Society of Chemical Industry     

Use of powdered vegetable coagulant in the manufacture of ewe's milk cheeses

A powdered vegetable coagulant obtained from the cardoon Cynara cardunculus and characterised as free of viable micro‐organisms, soluble and stable without the need for preservatives was evaluated, and compared with crude aqueous extract, in batches of Los Pedroches cheese, by determining various chemical, biochemical, microbiological and sensory parameters. Parameters were monitored over 3 months of ripening. High casein hydrolysis was observed after 2 days of ripening. The soluble nitrogen values reached at the end of ripening were over 34% of the total nitrogen in cheeses produced with both types of coagulant. For most parameters studied, no differences were observed between the two types of coagulant, although higher counts were observed for some microbiological groups in cheeses produced with crude aqueous extracts. The sensory quality of cheeses was practically identical with both types of coagulant. © 2002 Society of Chemical Industry     

Application of principal component analysis to chemical characteristics of Mahon cheese

 The chemical composition of the seven existing types of Mahon cheese, manufactured under the “Mahon” cheese Appellation of Origin, were studied. Of the cheeses, four were industrial (fresh, half-ripened, ripened and old-ripened) and three were traditionally manufactured (half-ripened, ripened and old-ripened). The chemical parameters were evaluated using ANOVA, Tukey’s multiple range test and principal component (PCA) analyses. Significant differences were found between Mahon cheeses ripened for different times in terms of moisture and non-protein nitrogen (NPN) contents (p <0.001); these differences were found to be independent of the manufacturing methodology, i.e. industrial or traditional. The ash and fat contents of industrially manufactured cheeses were significantly different from those in traditionally manufactured cheeses (p <0.001). PCA reduced chemical variables to two independent components: the first principal component was high in moisture, NPN content and water activity; the second, in NaCl, ash and fat contents. These results indicate that the seven types of Mahon cheese described by the “Mahon” cheese Appellation of Origin can be differentiated by their chemical characteristics. Received: 4 April 1997 / Revised version: 4 July 1997