Publication- Food Chem

Parente, E., H. Patel, V. Caldeo, P. Piraino and P.L.H. McSweeney (2012). RP-HPLC peptide profiling of cheese extracts: a study of sources of variation, repeatability and reproducibility. Food Chemistry 131, 1552-1560.

Publication- Int Dairy J

Costa, N.E., M.J. Mateo, D.J. O’Callaghan, V. Chaurin, M. Castillo, J.A. Hannon, P.L.H. McSweeney and T.P. Beresford (2012). Influence of an exopolysaccharide produced by a starter on milk coagulation and curd syneresis.. International Dairy Journal 22, 48-57.

Cheese fun

Click here for a little bit of fun... Nice website too.

Lactose-6 Production of lactose

Compared to sucrose, relatively small quantities of lactose are produced worldwide. Lactose is produced by concentrating whey (a by-product of casein and cheese manufacture) or ultrafiltration permeate by vacuum concentration followed by crystallization of lactose from the concentrate, and recovery and drying of the crystals. An alternative method for lactose preparation is the Steffen process (precipitation with Ca(OH)₂).

Applications of lactose in the food industry include in the manufacture of infant formulae (human milk contains more lactose than cows’ milk and hence cows’ milk-based infant formulae must be supplemented with lactose). Lactose has a low sweetness compared with other sugars. However, if properly crystallized, it has a low hygroscopicity which makes it suitable for certain uses in icing on confectionary products. Lactose is also used in the pharmaceutical industry as a diluent for tableting drugs (i.e., the small amount of active ingredient is “diluted” with lactose to make a sufficiently large tablet) and as a flavour adsorbent.

Course: October 2011

Course Programme

Milk Quality

• Seasonal variations in milk composition
• Somatic cell count and quality
Principles of Cheese manufacture
• Rennet gelation and curd formation
• Control of cheese composition
• Cheese Ripening
Cheese making Efficiency
• Definition, measurement and prediction
• Influence of key factors
• Milk standardisation/composition
• Milk Processing treatments
• Manufacturing parameters
Cheese composition and Quality consistency
• Prominent Quality Defects
• Bitterness, flavour defects
• Mottling, colour defects
• Cracks/Slits/Openings
• Crystalline deposits
Quality Assurance in Cheese Manufacture
Whey processing
•

Milk fat and fines recoveries from whey streams
• Manufacture of whey-based products

Publications- Encyclopedia of Dairy Sciences

McSweeney, P.L.H. (2011) Biochemistry of cheese ripening. In: Fuquay JW, Fox PF and McSweeney PLH (eds.) Encyclopedia of Dairy Sciences, Second Edition, vol. 1, pp. 667-674. San Diego: Academic Press.

McSweeney, P.L.H. (2011) Catalase, glucose oxidase, glucose isomerase and hexose oxidase. In: Fuquay JW, Fox PF and McSweeney PLH (eds.) Encyclopedia of Dairy Sciences, Second Edition, vol. 2, pp. 301-303. San Diego: Academic Press.

Cheese science course

Cheese course in Tomas Bata University, Zlin, Czech Republic. See here for details.

Dairygold Co-Op...

It is nice to see some good business news out of Ireland; Dairygold, the country's largest farmer-owned business, reported 60% increase in profits last year. And they are not alone; Kerry and Glanbia are doing very well also.

Publication- Encyclopedia of Dairy Sciences

Fuquay, J., P.F. Fox and P.L.H. McSweeney (eds). (2011). Encyclopedia of Dairy Sciences, 4 vols., 2nd ed., Elsevier, Oxford.

An alphabetical list of articles and abstracts is available here.

Lactose-5 Destabilisation of milk on freezing

Destabilization of casein micelles can occur on freezing. Crystallization of lactose as a-monohydrate binds up some unfrozen water. Hence, the amount of unfrozen water decreases and thus the Ca²⁺ concentration increases leading to destabilization of casein micelles. Also, since milk is supersaturated with respect to calcium phosphate, some precipitates on freezing:

3Ca²⁺ + 2H₂PO₄^- → Ca₃(PO₄)₂ + H⁺

Production of H⁺ leads to a drop in the pH of the unfrozen part from 6.7 to ~5.8, leading to further destabilization.

Destabilization can be avoided by:

· Reducing the rate of lactose crystallization (by using very low temperatures or increasing the viscosity of the product),

· Rapid freezing and agitation (this gives faster crystallization and less destabilization)

· Reduce lactose content (e.g., by ultrafiltration or lactose hydrolysis).

8th Cheese Symposium

8th Cheese Symposium, September 28 & 29, 2011, Moorepark, Fermoy, Co. Cork. For further details, click here.

Cheese Problems Solved- Russian Translation

Cheese Problems Solved has been translated into Russian (St Petersburg, 2010).

Lactose-4

When a-lactose is added in excess to water at 20°C, about 7 g per 100 g dissolves immediately (this is the true solubility of a-lactose). Some a-lactose then mutarotates to b-lactose until an equilibrium of 62.7b:37.3a is achieved. The solution is now unsaturated with respect to a-lactose and since the solubility of b-lactose is higher than that of a-, as b-lactose is produced by mutarotation, more lactose goes into solution until, at equilibrium, the final solubility is 18.2 g lactose per 100 g water (7 g a-lactose plus 11.2 g b-lactose).

If excess b-lactose is added to water, its initial solubility is ~50 g per 100 g. Some b-lactose then mutarotates to a-lactose to establish an equilibrium of 62.7b:37.3a. However, at this ratio and starting with 50 g b-lactose, the solution would contain 30.8 g b- and 19.2 g a-lactose, and thus would be supersaturated with respect to a-lactose. Some a-Lactose then crystallizes out of solution, upsetting the equilibrium and leading to further mutarotation from b- to a-lactose. These two events, i.e., crystallization and mutarotation continue until two criteria are met: 7 g a-lactose per 100 g in solution and a ratio of 62.7b:37.3a. The final solubility is the same, 18.2 g lactose (a + b), whether one starts with a- or b-lactose. However, since b-lactose is more soluble than a-lactose and mutarotation is slow, it is possible to form more highly saturated solutions by dissolving b- rather than a-lactose. However, the final equilibrium concentration and ratio is the same.

Lactose-3

Lactose exists in two anomeric forms and can mutarotate from the a- to the b- form and vice versa by changing the configuration around the anomeric carbon. If either a- or b-lactose is dissolved in water, there is a gradual change from one form to the other until an equilibrium is established. In water at 20°C, the equilibrium mixture is composed of 62.7% b- and 37.3% a-lactose. The proportion of a-lactose increases with increasing temperature. The final proportions of a- and b-lactose in the mixture are not influenced by pH, but the rate at which the mixture reaches equilibrium is slowest at pH 5.0. The a- and b- forms of lactose differ with respect to:

· Solubility

· Crystal size and shape

· Hydration of crystal form (and hence hygroscopicity)

· Specific rotation

· Sweetness.

Publication- Dairy Sci Technol

Bansal, N., P.F. Fox and P.L.H. McSweeney (2010). Inhibition of rennet activity in cheese using equine blood serum. Dairy Science and Technology 90, 673-685.