ICAR AICE-JRF/SRF Cream, Butter, Ghee & Milk Fat Products: practice questions

1 · Ghee making: creamery-butter, direct-cream, pre-stratification and desi methods · hard

Butter (1,000 kg, 16% water) is made into ghee. Pre-stratification removes 80% of the water as liquid serum before heating. Taking 2,257 kJ per kg of water evaporated and ignoring sensible heat, how much evaporation energy is saved?

1. 53.6 MJ
2. 361.1 MJ
3. 288.9 MJ
4. 72.2 MJ

2 · Cream processing: pasteurisation, neutralisation and ripening · medium

Why is sour cream neutralised before pasteurisation for butter or ghee?

1. Neutralisation is needed to activate the starter in cultured butter
2. Neutralisation removes feed taints by binding them to the alkali
3. Acid cream curdles on heating, and salted butter from it turns fishy
4. Neutralisation increases the fat content of the cream for churning

3 · Batch and continuous butter making · hard

In the accepted foam theory of churning, air bubbles:

1. Carry away the lactose so that the fat becomes insoluble and separates
2. Dissolve the globule membrane completely so the fat melts
3. Cool the cream until all the fat solidifies into one block
4. Collect globules whose damaged membranes let liquid fat glue them together

4 · Batch and continuous butter making · medium

In continuous (Fritz-type) butter machines, butter grains form:

1. Within seconds in a fast-beater churning cylinder
2. After several hours in a slowly rotating drum
3. By evaporation of water under vacuum
4. Only after the cream has been fermented overnight with culture

5 · Cultured and salted butter; dairy spreads · easy

Cultured butter differs from sweet-cream butter in that it:

1. Is made from cream fermented with an aroma culture
2. Contains at least 3% salt
3. Is made from cream heated to UHT temperatures before churning
4. Contains vegetable oil

6 · Cultured and salted butter; dairy spreads · medium

Why is salted butter usually made from sweet rather than cultured cream?

1. Salt cannot dissolve in acid serum
2. Salt combined with acidity promotes oxidative defects in storage
3. Cultured cream will not churn if salt is added
4. Salt kills the aroma culture, so that no diacetyl can ever form in it

7 · Cultured and salted butter; dairy spreads · hard

Which approach makes butter spreadable from the refrigerator while keeping it pure milk fat?

1. Raising the water content above 25% with stabilisers
2. Adding sugar to lower the melting point of the fat
3. Adding hydrogenated vegetable fat to raise its softness at 5 °C
4. Using olein fractions or cream ageing that leaves more liquid fat

8 · Butter defects and grading · hard

Fishy flavour in butter is associated with:

1. Unsalted sweet-cream butter stored frozen for a short time
2. Butter coloured with too much annatto or carotene
3. Butter made from cream pasteurised at too low a temperature
4. Salted butter from acid cream, with trimethylamine from lecithin

9 · Fractionation and modification of milk fat · easy

Dry fractionation of milk fat separates:

1. Water from fat
2. Fat from protein
3. Cholesterol from phospholipids
4. A high-melting stearin from a low-melting olein

10 · Fractionation and modification of milk fat · hard

Why is solvent fractionation rarely used for food milk fat?

1. It cannot separate any fractions from milk fat
2. Solvent cost and acceptance outweigh its sharper separation
3. It is required only for vegetable oils by law
4. It destroys all the triglycerides in milk fat