Reduction of Beta Cyclodextrin by Curd Washing in Low-Cholesterol Manchego Cheese

Beta-cyclodextrin (β-CD) is a cyclic oligosaccharide consisting of seven glucose units. β-CD is increasingly used in food research to reduce cholesterol due to its affinity for non-polar molecules such as cholesterol and as a natural additive. The purpose of this study was to evaluate the effect of curd washing in ewe's milk cheese on the reduction in cholesterol by β-CD from pasteurized ewe's milk Manchego cheese and the characteristics of its main components: milk, lipids, and flavor. An approximately 98.45% cholesterol reduction was observed in washed experimental cheeses that were treated by using β-CD. The remaining residual β-CD from the effect of curd washing was 0.15% in mature cheese, of the initial 1% β-CD treatment of the milk. The chemical properties (fat, moisture, and protein) did not change as a result of the curd washing with or without β-CD. The curd washing with or without β-CD on the levels of the various lipid fraction (fatty acids, triglycerides, and phospholipids) were comparable in treated and untreated cheeses. The effects of curd washing and the β-CD treatment did not significantly affect flavor components or short chain free fatty acids. The β-CD molecules were edible and nontoxic; as a result, they could be used safely in cholesterol removal processing in cheese manufacturing, improving the reduction in residual β-CD by curd washing by 85%. Therefore, the present study suggests that curd washing combined with β-CD is an effective process for cholesterol removal in Manchego cheese, preserving its desirable properties.

Expression and characterization of a novel lipase from Bacillus licheniformis NCU CS-5 for application in enhancing fatty acids flavor release for low-fat cheeses

A novel lipase from Bacillus licheniformis NCU CS-5 was expressed in different Escherichia coli cells. The recombinant enzyme achieved a high activity (161.74 U/mL) with protein concentration of 0.27 mg/mL under optimal conditions at the large-scale expression of 12 h. The recombinant lipase showed optimal activity at 40 ℃ and pH 10.0, and maintained more than 80% relative activity after 96 h of incubation at pH 9.0-10.0. This typical alkaline lipase was activated under medium temperature conditions (30 and 45 ℃ for 96 h). The lipase exhibited a degree of adaptability in various organic solvents and metal ions, and showed high specificity towards triglycerides with short and medium chain fatty acids. Among different substrates, the lipase showed the strongest binding affinity towards pNPP (Km = 0.674 mM, Vmax = 950.196 μM/min). In the experiments of its application in enhancing fatty acids flavor release for low-fat cheeses, the lipase was found to hydrolyze cheeses and mainly increase the contents of butyric acid, hexanoic acid, caprylic acid and decanoic acid. The results from NMR and GC provided the possibility of enhancing fatty acids flavor released from low-fat cheeses by the lipolysis method.

Influence of the Breed of Sheep on the Characteristics of Zamorano Cheese

This work aimed to study the effects of using ewe’s milk from Churra, Assaf, or both breeds on the physicochemical and sensory characteristics of Zamorano cheese at the end of ripening. Zamorano cheese is a hard variety with protected designation of origin (PDO) produced in the province of Zamora (Spain) with raw or pasteurized ewe’s milk. Five batches of Zamorano cheese were produced with pasteurized ewe’s milk. One batch was elaborated using milk from the Churra breed, the other using milk from the Assaf breed, and the remaining three employed milk mixtures of Churra and Assaf breeds in the proportions 75:25, 50:50 and, 25:75, respectively. Cheeses made with a higher proportion of Churra milk showed a predominance of hydrophilic peptides, while hydrophobic peptides predominated in cheeses with a greater percentage of milk from the Assaf breed. The largest content of most free amino acids was found in cheeses produced with the highest percentage of Churra milk. These cheeses presented the highest values for fat acidity index and free fatty acids content and showed greater elasticity and adhesiveness, as well as lower granularity and hardness. In the sensory evaluation, aftertaste and persistence were higher in these cheeses, being scored with the best overall values.

The ability of spore formers to degrade milk proteins, fat, phospholipids, common stabilizers, and exopolysaccharides

Spore formers are common spoilage-causing microorganisms in dairy products; however, their modes of spoilage (proteolysis, lipolysis, etc.) have not been described in detail for cultured dairy products such as sour cream and yogurt. The objective of the present study was to test the ability of spore-forming strains isolated from dairy environments for their spoilage-causing activities at typical sour cream (24°C) and yogurt (42°C) fermentation temperatures. A total of 25 spore-forming strains were isolated from different sources, including raw milk, pasteurizer balance tank, biofilms formed on heat exchangers, and milk powder. These strains were tested for proteolytic and lipolytic activities and for their ability to degrade phospholipids, common stabilizers (starch, gelatin, xanthan gum, pectin), and exopolysaccharides (EPS) at sour cream and yogurt fermentation temperatures. A higher percentage of positive strains was observed for selected activities at yogurt fermentation temperature compared with sour cream fermentation temperature. Identified proteolytic spore-forming strains, based on a skim milk agar method, were subsequently quantified for their level of proteolysis using non-casein nitrogen (NCN) content and sodium dodecyl sulfate-PAGE (SDS-PAGE). The proteolytic strains that showed the highest levels of proteolysis (highest percentages of NCN content) at 24°C were Bacillus mojavensis BC, Bacillus cereus DBC, Bacillus subtilis DBC, B. mojavensis DBC1, and Paenibacillus polymyxa DBC1. At 42°C the strains with the highest levels of proteolysis (highest percentages of NCN content) were B. subtilis DBC, B. mojavensis BC, B. mojavensis DBC1, B. cereus DBC, and Bacillus licheniformis DBC6. Results of SDS-PAGE demonstrated that proteolytic strains had primarily hydrolyzed β- and κ-CN. A viscometric method was used to evaluate the susceptibility of exopolysaccharides (EPS) to degradation by selected spore formers. This method helped to determine that EPS produced by commercial yogurt and sour cream cultures is susceptible to degradation by spore formers present in dairy environments.

Acceleration of Swiss cheese ripening by microbial lipase without affecting its quality characteristics

The effect of exogenous microbial lipase enzyme on the ripening of Swiss cheese (0, 200, and 800U lipase in 30 L milk) was investigated for the physico-chemical, textural and sensory properties, along with its microstructure. The aim of this study was to investigate the application of microbial lipase to accelerate the ripening without affecting its original desirable quality characteristics. The effect of the microbial lipase was studied at different time periods (2, 30, 45, and 60 days) of the Swiss cheese ripening stages. Statistical analysis of the results showed that the physico-chemical parameters of cheese slightly increased during the ripening. Also, at all stages of the ripening hardness of Swiss cheese increased while the brittleness decreased. The number and size of the fat globules were also affected by the addition of the lipases. This study also showed that increase in the lipase amount had no significant change in quality and sensory parameters. Therefore, 200U of lipase was found to be sufficient to reduce the ripening time from 90 to 60 days by maintaining its genuine quality. Thus, this study suggested that the addition of microbial lipase may significantly reduce the cost of the cheese production by lowering the ripening period by 1 month and maintaining the quality of the final product.

Effects of Proteolytic and Lipolytic Enzyme Supplementations on Lipolysis and Proteolysis Characteristics of White Cheeses

Effects of proteolytic (Neutrase, Bacillus subtilis-originate, 0.20 (P1) and 0.40 g 100 L-¹ (P2)) and lipolytic (Piccantase A, Mucor miehei-originated, 0.05 (L1) and 0.10 g 100 L-¹ (L2)) enzyme supplementations to cheese milk on lipolysis and proteolysis characteristics of 90-day ripened cheese samples were investigated in this study. While enzyme supplementation did not have significant effects on titratable acidity, fat and protease-peptone nitrogen ratios of cheese samples, dry matter, salt, protein, water soluble nitrogen, 12% trichloroacetic acid soluble nitrogen ratio (TCA-SN), 5% phosphotungstic acid soluble nitrogen (PTA-SN), casein nitrogen ratios, penetrometer value, total free fatty acids (TFFA) and total free amino acids (TFAA) were significantly influenced by enzyme supplementations. Individual free amino acids (15 of them) were also determined. Free amino acid contents of enzyme-supplemented cheeses were higher than the control cheese and the values increased in all cheese samples with the progress of ripening (p < 0.05). The highest amino acids in all periods of ripening were identified as glutamic acid, lysine, proline and aspartic acid. The major (Ca, P, Na, K, Mg) and minor (Zn, Fe, Cu, Mn) mineral levels of cheeses decreased with the progress of ripening and the effects of enzyme supplementations on these attributes (except for magnesium and manganese) were found to be significant (p < 0.01). As to conclude, enzyme supplementations increased proteolysis and lipolysis and accelerated ripening and thus reduced ripening durations. Especially the enzyme ratios in P1 and L1 cheeses were found to be suitable for reducing the ripening period in White cheese without any adverse effects.

Effect of Beta Cyclodextrin on the Reduction of Cholesterol in Ewe's Milk Manchego Cheese

Beta-cyclodextrin (β-CD) is a cyclic oligosaccharide consisting of seven glucose units and is produced from starch using cyclodextrin glycotransferase enzymes to break the polysaccharide chain and forming a cyclic polysaccharide molecule. The use of β-CD in food research for reduction of cholesterol is increasing due to its affinity for non-polar molecules such as cholesterol. The aim of this study was to evaluate the feasibility of using β-CD in cholesterol removal from pasteurized ewe’s milk Manchego cheese and evaluate the effect on the main components of the milk, lipids, and flavor characteristics. Approximately 97.6% cholesterol reduction was observed in the cheese that was treated using β-CD. Physicochemical properties (fat, moisture and protein) were not changed by the β-CD treatment, except the soluble nitrogen and non-protein nitrogen that showed slight differences after the treatment. The amount of the different components of the lipid fraction (fatty acids, triglycerides and phospholipids) were similar in cheeses treated and not treated with β-CD. Flavor compound and short chain free fatty acids were not mostly significantly influenced by the effect of the β-CD. β-CD molecules are edible and nontoxic and as a result they can be used safely for cholesterol removal processing in cheese manufacturing. Therefore, the present study suggests that β-CD treatment is an effective process for cholesterol removal from Manchego cheese while preserving its properties.

Review: Technological and organoleptic issues pertaining to cheeses with denomination of origin manufactured in the Iberian Peninsula from ovine and caprine milks Revisión: Aspectos tecnológicos y sensoriales de quesos con denominación de origen elaborados en la Península Ibérica con leche de oveja y de cabra

A few European countries have created Appélations d'Origine Protegée (AOP) in order to support legal protection and hence promote enforcement of high-quality standards of selected food products. This paper comprehensively reviews and updates fundamental and applied aspects encompassing tech nological and organoleptic characteristics of AOP traditional cheeses manufactured in the Iberian Peninsula, from ovine and/or caprine milks. Those cheeses from Portugal and Spain can be divided into four distinctive groups, based on milk source and rennet type: ( i) Azeitão, Castelo Branco, Évora, Nisa, Serpa, Serra da Estrela and La Serena cheeses, manufactured with raw ovine milk and coagulated via plant rennet; ( ii) Terrincho, Idiazábal, Manchego, Roncal and Zamorano cheeses, elaborated with raw ovine milk and coagulated via animal rennet; ( iii) Cabra Transmontano and Majorero cheeses, manufac tured with raw caprine milk and coagulated via animal rennet; and ( iv) Amarelo da Beira Baixa, Picante da Beira Baixa and Rabaçal cheeses, manufactured with mixtures of raw ovine and caprine milks and coagulated via animal rennet. Considerable differences between Portuguese and Spanish AOP cheeses exist; the former are, in general, characterized by softer consistencies and similarities to one another in terms of manufacturing protocols (usually encompassing coagulation of plain raw milk followed by slow draining of the curd), whereas the latter are, in general, larger and firmer.

Variations in conjugated linoleic acid (CLA) content of processed cheese by lactation time, feeding regimen, and ripening

Dairy products are major sources of conjugated linoleic acid (CLA); thus, an increase in CLA content can improve the quality value of dairy products. The objective of this work was to determine the effects of lactation time, feeding regimen, and ripening period on the level of CLA in processed cheese. CLA content in milk varied with the period of lactation; high in spring (April and May, about 6.8 mg CLA/g fat) and relatively low in mid summer and winter (about 4.3 mg CLA/g fat). The effects of dietary regimen and ripening period were determined in milk, which was obtained from March to May. After aging for 4 months, the cheese made from milk obtained from cows fed on pasture contained relatively higher levels of CLA compared to cheese made from milk obtained from cows fed indoors (8.12 mg CLA/g fat vs 6.76 mg CLA/g fat), but there was no difference in 7 month-aged cheeses. In both pasture and indoor feeding, 7 month-aged cheeses showed higher CLA content than 4 month-aged cheeses. The contents of stearic acid (C18:0) and linolenic acid (C18:3) were significantly higher in cheese from pasture fed cows compared to those in cows fed indoors. These findings should be helpful for the efficient production of functional dairy products with high CLA contents.

Esterolytic and lipolytic activities of lactic acid bacteria isolated from ewe's milk and cheese

In the present work, we report on the esterase and lipase activities of lactic acid bacteria representing the genera Lactococcus, Leuconostoc, Lactobacillus, and Enterococcus isolated from ewe's milk and cheeses. Esterase activity was studied using alpha- and beta-naphthyl derivatives of 2 to 12 carbon atoms and postelectrophoretic detection. The lactic acid bacteria evaluated had intracellular esterase activities, which preferentially degraded the alpha- and beta-naphthyl derivatives of 2 to 6 carbon atoms. By studying postelectrophoretic patterns, it was found that some strains presented more than one esterase. Lactobacillus plantarum O236 showed four enzymes that hydrolyze carboxyl ester linkages with different specificity. Lipase activity was studied in intracellular and extracellular fractions using tributyrin, tricaprylin, triolein, and milk fat as substrates. The intracellular and extracellular fractions of Leuconostoc mesenteroides O257, Lactobacillus plantarum O236, and Lactobacillus acidophilus O177 were able to hydrolyze tributyrin. L. plantarum O186, L. acidophilus O252, Enterococcus faecium O174 and O426, and Enterococcus faecalis Ov409 showed lipase activity associated with the intracellular fraction on tributyrin. Lactococcus lactis O233, L. plantarum O155, and Lactobacillus casei O190 did not hydrolyze triglycerides. Not all strains that showed esterase activity exhibited high activity on triglycerides. Esterase and lipase activities were species- and strain-specific. Wide variations in activity between strains highlight the need for selecting appropriate starters to produce enzyme-modified cheese as well as accelerated ripened cheese.

Proteolysis in Manchego-type cheese salted by brine vacuum impregnation

A new salting procedure based on the brine vacuum impregnation of porous products was tested on Manchego-type cheese and compared with conventional brine immersion. Its effect on cheese proteolysis throughout a 90-d ripening period was determined. Three cheese regions were evaluated (the rind, the middle, and the internal regions). The parameters analyzed were total N, water-soluble N, soluble N in trichloroacetic acid and soluble N in phosphotungstic acid by using the Kjeldahl method, casein profile by urea-PAGE, and peptide profile of the water soluble nitrogen extract by reverse-phase HPLC. Free amino acid formation was monitored with a spectrophotometric method by using a Cd-ninhydrin reagent. Globally, proteolysis was significantly affected by ripening stage (increasing throughout all the maturation period studied) and cheese region (rind showed a proteolysis pattern different from the middle and internal regions). The salting procedure only affected cheese proteolysis in the rind, whereas conventional brine-salted cheeses showed lower proteolysis than vacuum-impregnated cheeses.

Effect of the activity levels of the added proteolytic enzyme mixture on free amino acids in ripening Ossau-Iraty cheese

A proteolytic enzymatic preparation (using one of three enzyme concentrations and, hence, one of three different enzymatic activity levels) was added (before clotting) to the milk used to manufacture Ossau-Iraty ewes'-milk cheese. The free amino acids were analysed by reversed-phase high-performance liquid chromatography and the sulphosalicylic acid-soluble N fraction was quantified by the trinitrobenzenesulphonic acid method for use as an index of proteolysis during ripening. Sensory analysis of the cheeses began after two months of ripening. Use of the enzymatic preparation increased the rate of release of amino acids in an amount proportional to the enzyme concentration employed. The effect of the preparation was more pronounced in the early months of ripening, with the differences in the free amino acid contents of the various batches decreasing as ripening progressed. Levels of certain free amino acids, such as taurine, tyrosine and valine, were virtually unaffected by the addition of the enzymatic preparation, whereas levels of such amino acids as serine, glycine, arginine and proline were reduced. Texture defects in the cheeses were observed, namely, reduced elasticity and creaminess and increased brittleness. Similarly, enzymatic treatment also gave rise to bitter flavours that were not characteristic of the normal taste and aftertaste of Ossau-Iraty cheese and these changes were proportional to the quantity of enzyme added.