Crystallizing of the milk fat during aging

1. _____, cream is subjected to a program of cooling designed to control the fat so that the resultant butter has right consistency.

2. _____ is one of its most important quality-related characteristics, both directly and indirectly, since it affects the other characteristics – chiefly taste and aroma. Consistency is a complicated concept and involves properties such as hardness, viscosity, plasticity and spreading ability. The relative amounts of fatty acids with high melting point determine whether the fat will be hard or soft. Soft fat has some content of 3. _____ and at room temperature this fat has a large continuous fat phase with a low solid phase, i.e. crystallized high-melting fat. 4. _____, in a hard fat, the solid phase of high-melting fat is much larger than the continuous fat phase of low-melting fat is much larger than the continuous fat phase of low-melting fatty acids.

In butter making, if the cream 5. _____ to the same heat treatment it will be the chemical composition of the milk rat that determines the butter’s consistency. 6. _____ will make a soft and greasy butter, whereas butter from hard milk fat will be hard and stiff. If, however the heat treatment suits the iodine value of the fat the constancy of the butter can he optimized. For the 7. _____ regulates the size of the fat crystals, and the relative amounts of slid fat, and the continuous phase – the factors that determine the consistency of the butter.

Pasteurization causes the fat in the fat globules to liquefy. And when the cream is subsequently cooled a proportion of the fat will crystallize. 8. _____, the crystals will be many and small; if gradual the yield will be fewer but larger crystals. 9. _____ the more

solid be the fat that will crystallize to form the solid phase, and the less the liquid fat that can be squeezed out of the fat globules during churning and working.

The crystals bind the liquid fat 10. _____ Since the total surface area is much greater if the crystals are many and small, more liquid fat will be adsorbed than if the crystals were larger and fewer. 11. _____, churning and working will press only a small proportion of the liquid fat from the fat globules. The continuous fat phase will consequently be small and the butter firm. In the latter case, the opposite applies. A larger amount of liquid fat will be pressed out; the continuous phase will be large and the butter soft. 12. _____ for the cream, it is possible to regulate the size of the crystals in the fat globules and in this way influence both the

magnitude and the nature of the important continuous fat phase.

Task 6 Read the article below and write one word to fill the gap.

Treatment of hard fat

For optimum consistency where the iodine value 1. _____ low, i.e. the butterfat is hard, as much 2. _____ possible of the hardest fat must 3. _____ converted to as few crystals as possible, so that little of the liquid fat is bound 4. _____ the crystals. The liquid at

phase in the fat globules will thereby be maximized and much of it can be pressed out during churning and working, resulting 5. _____ butter with a relatively large continuous phase of liquid fat and with the hard fat concentrated at the solid phase.

The program of treatment necessary to achieve this result comprises the following stages:

− rapid cooling to about 8 °C and storage for about 2 hours 6. _____ this temperature;

− heating gently to 20…21 °C and storage at this temperature for at least 2 hours (water at 27…29 °C is used for heating); − cooling to about 16 °C.

Cooling to about 8 °C causes the formation of 7. _____ large number of small crystals that bind fat from the liquid continuous phase to their surface.

When the cream is gently heated to 20…21 °C the bulk of the crystals melt, leaving only the hard fat crystals which 8. _____ the storage period at 20…21 °C, grow larger.

After 1 – 2 hours most of the hard fat 9. _____ crystallized, binding little of the liquid fat. 10. _____ dropping the temperature now to about 16 °C, the hardest portion of the fat will 11. _____ fixed in crystal form while the rest is liquefied. During the holding

period at 16 °C, fat with a melting point of 16 °C or higher will be added 12. _____ the crystals. The treatment has thus caused the high-melting fat to collect in large crystals with little adsorption of the low-melting liquid fat, so that a large proportion of the butter

oil can be pressed out during churning and working.

UNIT 40

CHEESE PRODUCTION

Task 1 Read the article below and write one word to fill the gap.

Cheese

Traditionally, cheese 1. _____ made as a way of preserving the nutrient of milk. In a simple definition, cheese is the fresh or ripened product obtained 2. _____ coagulation and then separation of milk, cream or partly skimmed milk, buttermilk or a mixture 3. _____ these products. It is essentially the product 4. _____ selective concentration of milk. Thousands of varieties of cheeses have evolved that are characteristic 5. _____ various regions of the world.

Task 2 Mark whether the statements below are true or false:

A. Lipases, normally present in raw milk, are activated during pasteurization.

B. Nitrates may all be added to the cheese.

C. The addition of hydrogen peroxide is sometimes used as an alternative treatment for full pasteurization.

D. Homogenization is usually done for most cheese milk.

E. This less severe heat treatment results in a worse final flavor cheese.

F. An alternative heat treatment of 60 °C for 16 sec may also be used.

G. This treatment results in an increase of high initial bacteria counts before storage.

H. Cheese milk must first be clarified, separated and standardized.