145 | Lesson 4

Sugar Concentrates

These are products made by boiling together the fruit or its components and sugar to produce a solid product of at least 65%.

sugar concentrates

What is the sugar concentration of sugar concentrates?

at least 65%

What are the two modes of preservations of sugar concentrates?

1. high sugar concentration lowers Aw

2. plasmolysis

True or false: Sugar preservation is older than canning and freezing.

True

How does a high sugar concentration preserve food?

It creates high osmotic pressure, causing sugar to bind water and lower the Aw to levels unfavorable for the growth and reproduction of most microorganisms.

It is the partial dehydration of cells due to osmotic pressure.

plasmolysis

Why does plasmolysis occur in sugar concentrates?

The high sugar concentration outside the cells causes water to move out of the cells by osmosis.

What are the different types of sugar concentrates and their components?

1. jelly - clear fruit extract + sugar

2. marmalade - jelly + fruit/peel slices

3. jams - fruit pulp + sugar

4. fruit preserves - fruit slices + sugar syrup

5. candied fruits - fruit slice impregnated with sugar + drying

6. glazed fruit - candied fruit + coating + drying

These are sugar concentrates made with clear fruit extract and sugar.

jelly

True or false: Jelly can be made by boiling fruit without water.

True

What are the good characteristics of a jelly?

• clear, sparkling, transparent

• attractive in color

• semi-solid and jelled

• quiver but not flow

• not syrupy, sticky, or gummy

• retain the original fruit flavor and aroma

This sugar concentrate is made of jelly with fruit/peel slices.

Marmalade

What is jelly made of?

clear fruit extract + sugar

What is marmalade made of?

jelly + fruit/peel slices

This sugar concentrate is made of fruit pulp + sugar.

jams

What are jams made of?

fruit pulp + sugar

The consistency of this sugar concentrate should be firm enough to handle fruit tissues but not firm enough to retain the fruit’s original shape.

Jams

True or false: The consistency of jams should be firm enough to retain the fruit’s original shape.

False. Fruit preserves

True or false: Any fruit can be made to jams.

True

What fruits do jams require?

slightly underripe + ripe

This sugar concentrate is made of fruit slices + sugar syrup.

fruit preserves

What are fruit preserves made of?

fruit slices + sugar syrup

What is the sugar concentration of fruit preserves?

55-70%

This sugar concentrate contains about 55-70% sugar.

fruit preserves

Good fruit preserves should have fruit that:

• retains its form

• is crisp rather than soft

• is permeated with syrup

• does not shrivel

These sugar concentrates are made of fruit slices impregnated with sugar and subsequently dried to overcome stickiness.

candied fruits

This sugar concentrate is made of candied fruit that is coated and dried.

glazed fruit

What are the common coatings used to coat glazed fruits?

• concentrated sugar

• confectioner’s glaze syrup

What are the different components of sugar concentrates?

1. fruits

2. peels

3. gelling agent

4. sweetening agents

5. acidulants

What are examples of Group 1 Fruits (high pectin, high acid)?

• grapes

• lemons

• sour apple

• sour guava

• orange (sour)

• plum (sour)

GLSaSgOP

What are examples of Group 2 Fruits (high sugar, low pectin)?

• apple

• unripe banana

• sour cherry

• pear

• ripe guava

• peel or orange

• grapefruit

What are examples of Group 3 Fruits (low pectin, high acid)?

• strawberry

• pineapple

• sour peach

• sour apricot

• sweet cherry

SPSpSaSc

What are examples of Group 4 Fruits (low pectin, low acid)?

• ripe apricot

• ripe peach

• raspberry

• pomegranate

• overripe fruits

RaRpRP

Peels in a sugar concentrate should be _.

sliced and softened

How are peels in a sugar concentrate softened?

• prolonged boiling

• faster heating

• boiling in a basic solution (carbonate of soda, ammonium hydroxide)

What are the basic solutions used to soften fruit peels in sugar concentrates?

• carbonate of soda

• ammonium hydroxide

True or false: A gelling agent should not interfere with the odor, flavor, or taste of a sugar concentrate.

True

This consists of polymeric molecules that cross link to form a tangled, interconnected molecular network immersed in a liquid medium.

gelling agent

Formation of cross linkages between polymer molecules

gel network

This holds the water in a sugar concentrate and prevents it from flowing away.

gel network

Form of matter intermediate between a solid & liquid.

gel

Forces involved in a gel network.

• H bonding

• Ionic bonding

• Van der Waals forces

What are the three structures of an aqueous gel?

• junction zones

• interjunction segments

• entrapped water

These are the points where polymer molecules are joined/cross-linked and provide structure to the gel network.

junction zones

These provide structure to the gel network.

junction zones

These are the flexible sections of polymer chains between 2 adjacent junction zones.

interjunction segments

Is the water held within the polymer network of a sugar concentrate chemically bound?

No. entrapped

Give different types of a gelling agent.

1. gelatin

2. agar/alginates

3. gum arabic

4. starch/modified starch

5. pectin

This gelling agent is made from protein of animal origin extracted from bones and purified.

gelatin

This gelling agent is extracted from various seaweeds.

agar/alginates

Where are agar/alginates extracted from?

seaweeds

This gelling agent is exudated from acacia trees.

gum arabic

Where is gum arabic exudated from?

acacia trees

This gelling agent generally must not be boiled and should be added to warm syrup for setting on cooling.

Gelatin

This gelling agent is made for neutral jellies and weakened by boiling in acid solution.

agar/alginates

This gelling agent is used as extender and thickener in products, such as marshmallows.

starch/modified starch

This gelling agent is used largely in acid fruit jellies with low melting point and in in neutral jellies.

pectin

What is pectin used for as a gelling agent?

• acid fruit jellies with low MP

• neutral jellies

What is the pectin and acid content of Group 1 fruits?

high pectin, high acid

What is the pectin and acid content of Group 2 fruits?

high pectin, low acid

What is the pectin and acid content of Group 3 fruits?

low pectin, high acid

What is the pectin and acid content of Group 4 fruits?

low pectin, low acid