Free amino acid content of goat's milk cheese made with animal rennet and plant coagulant

BACKGROUND: Enzymes present in the flowers of Cynara cardunculus (cyprosins) are used in the production of some traditional Spanish and Portuguese cheeses, replacing animal rennet. The aim of this work was to study the changes that take place in free amino acids during the ripening of a goat's milk cheese (Murcia al Vino) manufactured with plant coagulant (PC) or animal rennet (AR). RESULTS: The total free amino acid (TFAA) concentration increased during ripening, with Ile, Val, Ala, Phe, Gaba, Arg and Lys representing more than 50% of the TFAA content at 60 days in both types of cheese. The TFAA concentration was significantly higher in cheeses made with PC (854 mg 100 g^?1 total solids (TS)) than those made with AR (735 mg 100 g^?1 TS). The concentration of most free amino acids, especially His, Ser, Gln, Thr, Ala, Met and Ile, was higher in the PC cheese. CONCLUSION: Cheese made using PC as coagulant presented higher contents of free amino acid throughout the ripening period than cheese made using AR. Therefore we can conclude that the use of PC to produce Murcia al Vino goat's cheese would accelerate the ripening process as a result of increased cyprosin proteolytic activity. Copyright © 2011 Society of Chemical Industry     

Influence of lamb rennet paste on the lipolytic and sensory profile of Murcia al Vino cheese

The influence of lamb rennet paste (71.1% chymosin, 177 international milk-clotting units/mL, 4.57U/g of lipase activity) during the ripening of Murcia al Vino goat cheese was studied. The aim of this study was to improve the knowledge of the effect of lamb rennet paste on the lipolytic patterns in this type of cheese by reference to the evolution of total and free fatty acids. A sensory analysis was carried out to compare cheeses made with commercial and paste rennet. The rennet paste showed higher lipolytic activity, enhancing the production of short-chain free fatty acids. In addition, the cheese produced with lamb rennet paste had a slightly more bitter and piquant taste, making it an attractive commercial alternative that can be used to develop new varieties of goat cheese.     

Influence of an artisanal lamb rennet paste on proteolysis and textural properties of Murcia al Vino cheese

The aim of this study was to evaluate the influence of lamb rennet paste on the proteolysis and textural properties of Murcia al Vino cheese, compared with calf rennet. The enzyme concentration was adjusted according to its milk-clotting activity. The use of rennet paste led to higher values of all nitrogen fractions studied. Significant increases were observed in the water-soluble nitrogen fraction as a result of the lower pH of rennet paste cheeses; although the rennet paste is not characterised, three proteases are reported in the references consulted which can justify the greater proteolysis compared with calf rennet. The use of natural rennet paste produces a cheese with a more hydrolysed protein matrix, which is associated with significant changes in texture. The greater firmness determined in the rennet paste cheese was associated with higher fracture stress, lower fracture strain and lower moisture content.     

Ripening of Camembert-type cheese made from caprine milk using calf rennet or kid rennet as coagulant

Camembert-type cheese was made from caprine milk using either calf rennet or kid 'Grandine' rennet as coagulant. The pH of all cheeses increased throughout ripening and levels of pH 4.6-soluble nitrogen increased from 8.1 to 18.2% of total nitrogen (TN) and from 6.9 to 20% TN for the cheeses made using calf rennet and kid rennet, respectively. Degradation of β-casein, measured by urea–polyacrylamide gel electrophoresis, and total and free amino acids were greater in the cheese made using kid rennet. Production of peptides, analysed by high performance liquid chromatography (HPLC), was slightly more extensive in the Camembert-type cheese made using calf rennet as coagulant. In general, a higher degree of proteolysis was found in Camembert-type cheese made from caprine milk using kid rennet than in cheese made using calf rennet as coagulant.     

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     

Influence of ripening on proteolysis and lipolysis of Murcia al Vino cheese

The aim of this study was to evaluate the influence of five different manufacturers and two ripening periods on the proteolysis and lipolysis patterns of Murcia al Vino goat cheese. The manufacturers significantly affected the water activity (a_w), pH, dry matter and fat content, several nitrogen fractions: water soluble nitrogen (WSN), trichloroacetic acid (12% w/v) soluble nitrogen (TCASN) and phosphotungstic acid (5% w/v) soluble nitrogen (PTASN); also the free amino acid (FAA) and free fatty acid (FFA) contents, with the exception of C_4:0, C_16:0 and C_18:0. Different ripening periods significantly affected the dry matter content, WSN and PTASN and all FAA, except serine.     

Proteolysis in miniature Cheddar-type cheeses made using blends of chymosin and Cynara cardunculus proteinases as coagulant

Miniature (20 g) Cheddar-type cheeses were manufactured using blends of Cynara cardunculus proteinases and chymosin as coagulant (100 : 0, 50 : 50, 25 : 75 and 0 : 100 C. cardunculus proteinases : chymosin). There were no substantial differences between the compositions of cheeses made using any of the four coagulant blends. Cheeses manufactured with coagulant blends containing C. cardunculus proteinases exhibited higher levels of pH 4.6-soluble nitrogen than cheese made using chymosin as coagulant. The extent of breakdown of α _s1 -casein, as measured by urea-polyacrylamide gel electrophoresis (urea-PAGE), was greater in cheeses made using coagulant preparations containing C. cardunculus proteinases as a constituent than in cheese made using 100% chymosin as coagulant. Different reverse-phase high-performance liquid chromatography (RP-HPLC) peptide profiles of the ethanol-soluble and -insoluble fractions were obtained for cheeses made using either C. cardunculus proteinases or chymosin as coagulant. Principal component analysis and hierarchical cluster analysis of RP-HPLC data confirmed that the inclusion of even small proportions (25%) of C. cardunculus proteinases with chymosin in the coagulant blend greatly altered the pattern and extent of proteolysis in miniature Cheddar-type cheeses.     

Physicochemical, microbiological and sensory changes during ripening and storage of Xinotyri, a traditional Greek cheese from raw goat's milk

Physicochemical, microbiological and sensory characteristics, evolution of lipolysis monitored by measuring acid degree value (ADV) and the main mineral elements were studied during ripening and storage of artisanal Xinotyri cheese from raw goat's milk. Cheeses were characterized by a high content in total solids (TS; 83%) and fat (59% of TS), and very low pH (4.0), water activity (0.87) and moisture (17%). Protein and salt contents at the end of storage were 31% and 2.8%, respectively. Lipolysis increased, while variations in mineral (Ca, P, Mg and Zn) content were found during ripening and storage. Cheeses were free of Salmonella and Listeria in 25 g, while enterobacteria, pseudomonads, and coagulase-positive staphylococci were < 100 cfu/g. Mesophilic lactic acid bacteria increased above 8 log cfu/g by day 6, but declined by 2–3 logs in the ripened cheese (45 days) and by 3–4 logs during cheese storage at 4°C for up to 180 days.     

Comparison of the characteristics of teleme cheese made from ewe's, goat's and cow's milk or a mixture of ewe's and goat's milk

Teleme cheeses were manufactured from ewe's, goat's and cow's milk and mixture of ewe's and goat's milk. Physicochemical and biochemical analyses of the cheeses at various stages of ripening and storage were performed. Cheeses made from goat's milk had lower moisture content than those made from other milks. No significant differences in the mean values of protein, salt and water activity (a _w ) of the different cheeses at all ages studied were found. Cheeses from goat's and cow's milk had higher contents of fat and fat in dry matter (FDM) compared to that of cheeses from ewe's milk and mixed milk. Significant differences were observed in the yield and yield on 56% moisture: cheeses from ewe's milk gave the highest yield and cheese from cow's milk the lowest. Significant differences were found in the ashes content of the different cheeses at all ages. No differences in cholesterol and cholesterol/fat contents of the four types of cheeses were found. Main and trace elements showed variability among the four cheeses.     

Physicochemical,microbiological, textural and sensory changes during the ripening of pasteurised goat milk cheese made with plant coagulant (Cynara scolymus)

This study describes the changes that occur during the ripening of cheeses made with a plant coagulant derived from artichoke flowers (Cynara scolymus). The results indicate that the physicochemical composition during ripening evolves similarly to other cheeses. The texture and sensory features of the cheeses during ripening evolved differently from that observed for other goat cheeses. Although it is common for a bitter taste to develop during the ripening of cheeses elaborated with plant coagulants, bitterness was scored very low in the cheeses made with artichoke, so that these cheeses could be suitable for marketing.     

Quality evaluation of mozzarella cheese made from buffalo milk by using paneer booti (Withania coagulans) and calf rennet

This systematic research was conducted to assess the suitability of Withania coagulans for the preparation of mozzarella cheese from buffalo milk. The extract of dried berries of paneer booti (W. coagulans) was prepared in three buffers separately viz. Tris‐HCl, phosphate, NaCl and appropriate concentration of crude extracts were tested for their milk coagulating activity. NaCl solution with 0.85% strength was found to be suitable for milk coagulation without any objectionable taste and flavour. The results revealed that 15 μL crude enzyme extract per mL of milk was the optimum concentration for coagulation while 4.25 and 37 °C were the best levels of pH and incubation temperature for coagulation respectively. Mozzarella cheese prepared from crude enzyme extract was compared with the cheese prepared by calf rennet using acidification process. There was a nonsignificant difference among all tested parameters of both the coagulants. These findings support the suitability of an aqueous extract of W. coagulans for the commercial preparation of different types of mozzarella cheeses.     

Compositional characteristics and nutritional quality of Chinese mitten crab (Eriocheir sinensis)

Chinese mitten crab (Eriocheir sinensis) was analyzed for proximate composition, minerals, amino acids and fatty acid composition, and also evaluated for nutritional quality. The yields of crab meat and edible viscera were 24.2% and 9.2%, respectively. The crab meat contained 18.9% crude protein. About 80% of the protein resided in the crab meat portion, while about 90% of the fat was in the viscera. Chinese mitten crab was an excellent source of minerals, particularly zinc, iron, copper and phosphorus. The crab protein contained high amounts of glutamic acid (151 mg/g), aspartic acid (99 mg/g), arginine (99 mg/g), lysine (81 mg/g) and leucine (77 mg/g), and it was a high quality protein with well-balanced essential amino acid compositions. Twenty six fatty acids were found in the crab oil. The monounsaturated fatty acids were predominant with a percentage of 49.8. Oleic acid (18:1) was the dominant fatty acid, followed by palmitoleic acid (16:1), palmitic acid (16:0) and linoleic acid (18:2n − 6); and the percentages were 31.0, 14.3, 14.2 and 11.9, respectively. The ratio of n − 6/n − 3 polyunsaturated fatty acids (PUFAs) was 2.2, and this is a n − 3 PUFA-rich food. In short, the results showed that Chinese mitten crab is a nutritious food.     

Comparison of buffalo cottage cheese made from aqueous extract of Withania coagulans with commercial calf rennet

An aqueous extract of Withania coagulans was used to prepare cottage cheese from buffalo milk and its quality attributes were compared with cheese made from commercial rennet. Both cheeses contain satisfactory ranges of 49.6–54.7% moisture, 21.3–24.3% fat and 21.4–23.6% protein. The type of coagulant had no significant effect on acidity, protein and ash contents of both the cheeses. W. coagulans cheese showed a significantly (P < 0.05%) higher pH and moisture contents. Similarly, no marked differences were observed in their organoleptic evaluation, actual and theoretical yield. These results supported the fact that W. coagulans is a promising rennet substitute for cottage cheesemaking.     

Compositional characteristics and volatile organic compounds of traditional PDO Feta cheese made in two different mountainous areas of Greece

The compositional characteristics of Feta cheese manufactured in two mountainous areas from raw milk, from sheep fed by grass, and the forages’ volatile organic compounds (VOC) were studied, to differentiate the Feta cheese. Although the main compositional features did not vary greatly, the proteolysis mode was altered. The VOC profiles of the cheeses varied. While some VOCs were common to both groups of cheeses, others were discriminatory for each production area. There were common terpenes in both the bulk forage and the mature cheeses. Overall, the VOC composition of Feta could provide a basis for identification with regard to its region of origin.     

Changes of free amino acid content of Teleme cheese made with different types of milk and culture

The evolution of concentration of free amino acids in Teleme cheese made from sheep, goat or cow milk, using a thermophilic, mesophilic or a mixture of a thermophilic, a mesophilic culture throughout ripening was studied. The total free amino acid (TFAA) content increased at all stages of ripening, regardless of the milk and culture used. In general, the TFAA content was higher in cheeses made from cow’s milk than that of the cheeses made from ewe’s milk; cheese from goat’s milk ranged over intermediate levels. Also, higher concentrations of TFAA were found in cheeses made with the thermophilic than with the mesophilic culture. Cheeses made with the mixture of thermophilic–mesophilic culture ranged over intermediate levels. The results of this study have shown that Leu, Glu, Phe, Val and Lys were the major FAA of Teleme cheese at all stages of ripening, regardless of the type of milk and culture used.     

Compositional,biochemical and textural changes during ripening of Tulum cheese made with different coagulants

In the present study, biochemical, chemical and texture changes in Tulum cheeses made using calf rennet and microbial rennets (Aspergillus niger protease and Rhizomucor miehei protease) were compared during ripening for up to 90 days. A total of 15 free fatty acids (FFAs) were detected in the cheese samples. The peroxide values (PV) of the cheeses increased significantly (P < 0.05) during ripening and the cheese made with calf rennet had the highest PV. Proteolysis in the cheeses increased as the ripening time increased. α_s1‐casein and β‐casein degradation was higher in cheeses manufactured with R. miehei protease. Cheeses made with calf rennet were significantly (P < 0.05) harder, more adhesive, more cohesive and more resilient than those made with microbial rennet.     

Influence of the frozen storage on some characteristics of ripened Manchego-type cheese manufactured with a powdered vegetable coagulant and rennet

A study was made of the effect of freezing and nine months’ frozen storage on the chemical, microbiological and sensorial characteristics of fully ripened Manchego-type cheese. Chemical components, water activity and nitrogen compounds were not altered by freezing and frozen storage. Soluble and non-protein nitrogen were significantly higher in cheeses produced with the powdered vegetable coagulant (PVC) compared to those made with rennet. Proteolysis continued slowly during frozen storage, with higher amino acid and ammonia nitrogen rates at the end of the storage period. Micrococci (P-value <0.05, in cheese made with PVC) and staphylococci counts tended to decrease during frozen storage; however total viable, lactic acid bacteria and mold-yeasts counts were similar throughout the nine months. Changes in sensorial parameters were observed (P-value <0.05) throughout freezing and frozen storage, affecting the creaminess of cheeses made with chymosin and the taste intensity and salty taste of cheese obtained with vegetable coagulant. Cheeses obtained with PVC proved to have a more acid taste and greater taste intensity (P < 0.01) as well as displaying a more bitter taste, greater creaminess and lower degree of hardness (P-value <0.001) than those produced with rennet.     

Effect of gender on the meat quality characteristics and chemical composition of kudu (Tragelaphus strepsiceros), an African antelope species

The kudu (Tragelaphus strepsiceros), one of Africa’s most majestic antelope species, shows a strong sexual dimorphism. The male reaches a larger size (≈250 kg live weight) than the female (≈180 kg live weight). Kudu occur throughout the savannah regions in central Africa, south of the equatorial forests, through East Africa to Ethiopia, Sudan and Chad down to the Eastern Cape (South Africa). Kudu are predominantly browsers, but will occasionally graze. Within South Africa, this species is hunted regularly for local consumption, and Kudu meat is also a regular item in most restaurants that serve game meat and is also frequently exported. However, very little data has been published pertaining to the muscle chemical composition and other quality attributes of its meat. In the present investigation, the proximate, amino acid, fatty acid and mineral chemical compositions of the Longissimus dorsi et lumborum muscle of 18 animals are presented, and the effect of gender thereupon tested by means of standard student’s t-tests. Kudu meat has a high protein and a low fat content. Only two of the longer chained polyunsaturated fatty acids (C20:3n−6 and C20:5n−3) differed between the females and males, the latter having a higher concentration each time. Of the kudu muscle’s fatty acids, 37% were saturated, 22% monounsaturated and 41% polyunsaturated. The mean PUFA to SFA ratio (1.12) was well above the recommended 0.45 prescribed by the British Department of Health. The n−6:n−3 PUFA ratio (2.34) was also well below the British Department of Health’s recommended figure of four. Histidine and valine had significantly higher levels in female kudu meat than in male kudu meat. Phosphorus was present at the highest concentrations in both female and male animals. Overall, the chemical composition of kudu meat is not significantly effected by gender.     

Fatty acids of a salami-type sausage made of Baltic herring fillets, pork and lard

 The fatty acid composition of "fish wurst", a fermented salami-type sausage made of pork, lard and Baltic herring fillets (Clupea harengus var. membras) was investigated. Changes in the proportions of the 35 most abundant fatty acids were examined throughout the 1-month ripening period followed by a 4-month storage period. The fat composition of the product was stable (32–35%) and retained the characteristics of the main ingredients: oleic acid (37.4%, mean of three production batches) palmitic acid (23.7%) and linoleic acid (10.7%) from lard and fish, stearic acid (11.7%) mainly from lard, and palmitoleic acid (3.0%) and long-chain (C20–C24), polyunsaturated fatty acids (c.a. 6%) mainly from fish. During the 4-week ripening period a statistically significant increase (P≤0.05) was detected in the proportions of minor fatty acids only, i.e. eicosenoic acid (20 : 1n-9), eicosadienoic acid (20 : 2n-6), docosadienoic acid (22 : 2n-6) and docosatrienoic acid (22 : 3n-3). During the 4-month storage of the ripe sausage, the fatty acid composition stabilized. Only the proportion of stearic acid increased significantly during storage, from 11.7% to 12.5%. Received: 23 January 1998 / Revised version: 1 April 1998