ICAR AICE-JRF/SRF Ice Cream & Frozen Dairy Desserts: practice questions

1 · Classes of frozen desserts and their standards · hard

Why does a minimum weight-per-volume rule matter for ice cream manufacturers?

1. It sets the minimum freezing temperature for storage in shops
2. It fixes the maximum sugar content that may be used in mix
3. It caps how much air, as overrun, can be sold as product
4. It requires all ice cream to be hardened in tunnels below −30 °C

2 · Freezing: batch and continuous freezers · medium

Increasing dasher speed in a freezer tends to:

1. Lower fat destabilisation and remove frictional heat
2. Stop air incorporation completely
3. Have no effect on product structure at all
4. Raise fat destabilisation and add frictional heat

3 · Overrun calculation and control · medium

Which mix change generally improves air incorporation?

1. Higher total solids and protein with proper ageing
2. Lower total solids with no stabiliser at all
3. Skipping ageing to keep the fat liquid
4. Removing all emulsifiers from the mix

4 · Hardening, storage and heat shock · medium

Why must ice cream be hardened quickly after the freezer?

1. Fast hardening adds new air cells that raise overrun
2. Slow hardening makes the fat melt and churn into butter
3. Slow hardening grows fewer, larger crystals
4. Fast hardening converts lactose into a glassy state

5 · Ice cream structure: ice crystals, air cells, fat network · easy

Physically, ice cream is best described as:

1. A partly frozen foam with ice, air and fat in unfrozen serum
2. An oil-in-water emulsion with no air cells
3. A frozen sugar solution with no dispersed phases of any kind in it
4. A gel of casein with trapped sugar crystals

6 · Ice cream structure: ice crystals, air cells, fat network · medium

What stabilises the air cells in ice cream?

1. Dissolved sugar that thickens the air itself
2. Partly coalesced fat and adsorbed protein at their surfaces
3. Lactose crystals that form a shell round each cell
4. Ice crystals that freeze onto the cell walls only

7 · Reduced-fat and reduced-sugar ice cream · medium

Which is a protein-based fat replacer used in reduced-fat ice cream?

1. Polydextrose, a glucose polymer
2. Inulin
3. Microparticulated whey protein
4. Maltodextrin

8 · Defects and their causes · medium

Coarse, icy texture in ice cream is most often caused by:

1. Lactose crystals from too much MSNF
2. Air cells from low overrun
3. Large ice crystals from slow freezing or heat shock
4. Fat particles from an excessive emulsifier dose

9 · Overrun calculation and control · hard

A batch freezer turns 10 L of mix (density 1.10 kg/L) into ice cream whose density is 0.62 kg/L. What is the overrun?

1. 56.4%
2. 43.6%
3. 77.4%
4. 177.4%

10 · Hardening, storage and heat shock · medium

At a constant storage temperature, which change still slowly coarsens ice crystals?

1. Sublimation of air from the cells into the ice
2. Conversion of ice into glassy lactose crystals
3. Ostwald ripening of small crystals into larger ones
4. Nucleation of many new small crystals in the serum