Carbohydrates 2

Question 1

Where do the following crops grow?:

Sugar cane
Sugar beet

Answer 1

Sugar cane - hot, tropical climates
Sugar beet - cooler climates.

Question 2

Sugar cane and sugar beet account for most of the world’s sugar - what % does each represent?

Answer 2

Sugar cane - 80%
Sugar beet - 20%.

Question 3

Cereals are members of the poaceae (gramineae) family - they are related to what?

Answer 3

Grasses!

Question 4

Cereals are grasses specifically bred to produce large …………… that can gather a lot of ……….. in the endosperm.

Answer 4

Seeds, energy.

Question 5

Cereals are the world’s most important crop - what % of the world’s calories do they represent?

Answer 5

60%.

Question 6

Of the top six crops grown worldwide, how many are cereals?

Answer 6

Five - the other is soy beans.

Question 7

Which are the top five cereals grown in the UK?

Answer 7

Wheat, barley, oats, rye and triticale.

Question 8

What endosperm texture do millers look for in wheat? Why?

Answer 8

Hard. Hard endosperms are more easily milled, they keepe their structure and are easy to sieve.

Question 9

Wheat that allows bran to be separated from germ to produce white bread is easily…?

Answer 9

…milled.

Question 10

Why is stronger flour better for bread baking?

Answer 10

Stronger flour gives a better rise because it can retain the carbon dioxide bubbles given off by yeast, therefore producing a larger loaf with a better texture.

Question 11

What protein content do millers look for in wheat?

Answer 11

Over 13%. Higher protein content = higher wheat prices.

Question 12

Why is it important that wheat has good protein quality, specifically glutenin and gliadin?

Answer 12

Glutenin and gliadin form gluten when hydrated which gives bread its elasticity and a good colour.

Question 13

What is the Hagberg Falling Number Test?

Answer 13

It measures the number of seconds it takes for a plunger to fall through wheat flour in water. It shows the alpha-amylase content of the grain.

Question 14

What does a high Hagberg Falling Number mean? And a low one? What Hagberg Falling Number do millers look for in wheat?

Answer 14

A high Hagberg Falling Number means that the plunger takes a long time to fall, so the mixture of flour and water is thick with starch.

A low Hagberg Falling Number shows that the plunger has fallen quickly because the starch has been converted to sugar.

Millers look for a Hagberg Falling Number of over 250, meaning that the wheat is LOW in alpha-amylase and therefore the carbohydrates will not be broken down before baking.

Question 15

Do millers prefer wheat to have higher or lower water absorption?

Answer 15

Millers prefer wheat with a higher water absorption, as water hydrates gliadin an glutenin which form starch, making better bread.

Question 16

What specific weight do millers require in bread (in kg/hl)? Why?

Answer 16

Millers want wheat with a specific weight of over 76kg/hl. This means the grain is low in moisture and it therefore requires careful transportation, harvesting and storage.

Question 17

What sample purity do millers require wheat to have?

Answer 17

Millers require wheat with less than 2% admix.

Question 18

What is admix?

Answer 18

Anything that is not pure, unbroken whole grains. It can include broken grains, weeds, seeds, dust etc.

Question 19

What can growers do to influence wheat quality?

Answer 19

Grow the right variety.
Apply fertiliser at the right time.
Select fertile fields.
Careful grain drying.

Question 20

How can farmers try and make their fields more fertile?

Answer 20

By planting after a nitrogen-fixing crop, such as legumes or a break crop.

Question 21

What do farmers do at the right times, such as tillering, stem extension and ear emergence, to achieve better grain quality? Why?

Answer 21

Farmers apply fertilisers at the right time to ensure an adequate supply of nitrogen throughout crop growth.

Question 22

How does rain in June influence grain’s quality?

Answer 22

Higher protein content.

Question 23

What can farmers do to mitigate the effects of the rain on crops?

Answer 23

Adjust fertiliser application accordingly.

Question 24

What is the MAIN determinant of protein quality?

Answer 24

Variety.

Question 25

How does drying affect grain quality?

Answer 25

Grain quality can be adversely affected by overdrying or high temperatures because proteins can be degraded. Grain must therefore be carefully mixed when drying to avoid hotspots.

Question 26

What is ‘lodging and sprouting’?

Answer 26

Lodging is if a grain falls over, the plant will stay wet for longer.

If grain stays wet for too long, the alpha-amylase content increases, leading to the wheat sprouting in the field.

Question 27

Why does wheat need to be harvested in good weather?

HINT: it has to do with specific weight.

Answer 27

Milling wheat is prone to drought and any wheat that is left out in the field for too long once it is mature will decrease in quality.

Question 28

Why is it important to choose the correct combine harvester settings when harvesting wheat?

Answer 28

To avoid as much admix as possible.

Question 29

What is ergot? How can it be prevented?

Answer 29

A highly toxic fungi. Any crop which is contaminated with ergot MUST be destroyed! Crop rotation can help to reduce sources, as can planting away from grass seeds which can harbour ergot.

Question 30

What is the AHDB recommended list?

Answer 30

An annual list produced for farmers to help them decide which varieties are best to grow. depending on end-use, quality, etc.

Question 31

What are the three main uses of barley?

Answer 31

Malting/distilling, animal feed and seed production.

Question 32

What is the germination rate that maltster’s require for barley?

Answer 32

100%. Germination musct be rapid and uniform across the grain.

Question 33

Do maltster’s prefer a higher or lower nitrogen content for barley? Why?

Answer 33

Maltsters prefer barley with a lower nitrogen content.

Lower nitrogen content means that the grain is higher in carbohydrates and therefore gives a higher yield of malt extract.

A high nitrogen content can make beers cloudy and unstable.

Question 34

Is a larger or smaller barley grain size preferable?

Answer 34

A larger grain size is preferable because it gives a higher yield of malt extract.

Question 35

Maltsters want barley to have a moisture content of 14.5%. What happens to grains that have been overdried?

Answer 35

They will die!

Question 36

Why is it important that barley is free from damage and admix?

Answer 36

It makes malting and distilling easier to industrialise.

Thinner skins mean that there is less non-productive husk.

Broken grains won’t germinate.

Question 37

Is spring barley or winter barley better for malting?

Answer 37

Spring barley.

Question 38

What can growers do to influence the quality of barley?

Answer 38

Select the right site for growing - free draining soil, but not excessively drought prone. Usually grown after a cereal crop. Growers prefer soil with a lower nitrogen content so that they can control it more easily.

Sowing early for a uniform grain size.

Balancing nitrogen input.

Carefully timed harvesting with minimal damage to grain.

Careful drying - too hot reduces germination.

Question 39

What impact does a high nitrogen input have on barley?

Answer 39

It can increase yield, BUT there is a higher risk of lodging, too many small grains being produced and excessive grain nitrogen, beyond maltster’s requirements.

Question 40

What are the three main stages of wheat milling?

Answer 40

1. Removing contaminants.
2. Conditioning.
3. Milling.

Question 41

Before wheat leaves the field, light material is removed by …………….. and ……………… using tumblers and air blowers.

Answer 41

Threshing, winnowing.

Question 42

After it leaves the field, where does wheat go? What is removed at this stage?

Answer 42

Wheat goes to the screenroom where harder materials (e.g. stones, metal) are removed along with other non-grain material.

Question 43

Impurities in wheat are separated based on which properties?

Answer 43

Specific gravity and air resistance.

Question 44

Describe the process of wheat conditioning. Why does wheat need to be conditioned?

Answer 44

Wheat is soaked in water vapour for 6-36 hours. Harder types of wheat are soaked for longer.

This soaking controls the moisture content to a specific % - 15%-15.5% for soft wheat, 16.5% for hard wheat.

Conditioning helps to separate the outer bran from the starchy endosperm by softening the endosperm and toughening the outer layers of the grain.

Question 45

What can be a negative consequence of wheat conditioning?

Answer 45

Soaking the wheat can introduce bacteria, yeast and mould.

Question 46

What is debranning? What are the advantages and disadvantages of debranning in milling wheat?

Answer 46

Debranning is a process whereby bran is remove by abrasion.

It is considered not very effective in wheat because of the ‘crease’ down the grain, BUT it does make superior bread.

Question 47

What do plan sifters do in wheat milling?

Answer 47

They remove most of the bran (as semolina) and germ.

Question 48

In wheat milling, what are reduction rolls?

Answer 48

Reduction rolls produce flour with the correct specification dependent on application.

Question 49

In the reduction system, is the most valuable flour (i.e. whitest, no bran, finest semolina) produced at the end or the beginning of the process?

Answer 49

The most valuable flour is produced at the beginning of the reduction system.

Question 50

How is the quality of flour assessed?

Answer 50

By colour and ash content.

Question 51

Does a lower ash content mean that a flour has more or less bran inclusions?

Answer 51

Flour with a low ash content has a lower amount of bran.

Question 52

What is the ultimate aim of wheat milling and finishing?

Answer 52

To maximise the extraction rate of high value white flour whilst staying within the required colour and/or ash specification.

Question 53

What is very white flour supplemented with at the finishing stage?

Answer 53

Calcium, iron, thiamine and niacin.

Question 54

How is wholemeal flour produced?

Answer 54

White flour streams are blended with bran and germ.

Question 55

What is the main reason for milling rice?

Answer 55

The hull is unsuitable for human consumption!

Question 56

What is the difference between white rice and brown rice?

Answer 56

Brown rice has had just the hull removed. White rice is then polished.

Question 57

Brown rice has a high lipid content of 2.4%-4%. What problems can this cause?

Answer 57

It becomes rancid and can be subject to insect infestation.

Question 58

What is lost when brown rice is polished into white rice?

Answer 58

15% protein
65% lipid and fibre
55% minerals
80% thiamine
55% riboflavin
65% niacin.

Question 59

Name the stages of rice milling.

Answer 59

1. Remove the contaminants.
2. Polishing (remove bran).
3. Grader (and sometimes grinder).

Question 60

After grading, it is desirable for rice to contain a minimum number of…?

Answer 60

…broken kernels.

Question 61

As the grade of rice decreases, the amylose content decreases. What characteristic does this give to the rice?

Answer 61

Stickiness.

Question 62

White polished rice can be graded into four categories. Name them, from best to worst.

Answer 62

1. Head rice.
2. Broken rice.
3. Second-hand screenings.
4. Brewer’s rice.

Question 63

Which of these qualities of rice are desirable and which are undesirable?

Chalkiness
Amylose/amlopectin levels
Translucence
Cracking

Answer 63

DESIRABLE
Translucence
Amylose/amylopectin levels

UNDESIRABLE
Chalkiness
Cracking