high sugar concentration

7/28/2019 High Sugar Concentration

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High Sugar Concentration


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sugar concentration of 60% in finished or

processed fruit products generally insures

preservation

preservation is determined

osmotic pressure of sugar solution

water activity values in the liquid phase


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Basic Ingredients

Fruit

Sugar

Acid Pectin

combination of them will ensure the good gel

formation, which act as the most important

quality


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Fruit

gives each product the characteristic of

flavour, taste, colour

provides at least part of the pectin and acid

needed for successful gel formation

fruits that are rich in flavour are best because

the large proportions of sugar necessary for

proper consistency and good keeping quality

dilute the fruit flavour


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Fruit

supplies the water needed to dissolve the

other ingredients and some or all of the pectin

and acid


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Sugar

Preservative (lowers Aw)

Fruit jams that are not prepared with the correct

sugar content and thoroughly cooked can allow

harmful microbes to grow


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Pectin

a chain ofpolygalacturonic acid which has a

molecular weight up to 150000

primary gelling agent - as thickener

if pectin in fruit is not enough- commercial

During ripening, pectin is broken down by the

enzymes pectinase and pectinesterase


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Pectin structure


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Acid

Citric acid

Lime and lemon juice

Acidity of the jam/jelly should be pH 3.0 needed to maintain the pectin structure

the addition of acid which high in H+ ion will

bind to dissociated COO- that will shift theequilibrium to the left hand side

COOH = COO- + H


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Jam

Jelly

Marmalade Fruit butters

Fruit Preserves


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Jam

made from whole or cut fruits,cooked to a pulp with sugar,

producing a thick, fruity, spread

total soluble solid TSS must not less

than 65%

contains 32-34% water

Gel formation

dependent on pectin content


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should be bright and rich in colour

reflecting the colour of the fruit

should have the full flavour of the fruitused and set without becoming too stiff

fruits that have low taste and flavour can

be mixed with those that have a strongertaste


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Type of Jam Moisture

content %

Sugar (as invert

sugar, %)

Vitamin C mg/100

g

Jam made

from berry

fruits:

strawberry,

raspberry, etc.

29.8 69.0 10 - 25

Jam made

from stonefruits: apricot,

peach, etc.

29.6 69.3 10 - 35


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Jelly

made from the juice of the fruit andsugar

clear and sparkling when finished

firm enough to hold its shape


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Marmalade

soft, transparent fruit jellies that contain small

pieces of fruit or citrus peel


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Fruit butters

are made from fruit pulp cooked with sugar

until thickened


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Fruit preserves

are made of small, whole fruits or pieces of

fruits in a clear, thick, slightly gelled syrup


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Preserving High Sugar Preserves

molds can still grow on the surface of theseproducts unless they are heat-processed

Mycotoxins

cause cancer in animals have been found in some jars of jelly with surface

mold growth.

Paraffin or wax seals don't prevent moldgrowth and are no longer recommended forsealing any sweet spread, including jelly


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Preserving High Sugar Preserves

To prevent mold growth

pour hot sweet spreads into sterilized jars

leave 1/4-inch headspace Seal

Process

use the processing time recommended for youraltitude


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Making jelly/jam

without added pectin

firm fruits naturally high in pectin

three-fourths ripe and one-fourth under ripe fruit.

Use at most 6 cups 8 cups of fruit juice at a

time and combine the right amounts of juice,

sugar and lemon juice

Heat to boiling.

Stir until the sugar is dissolved.

Boil over high heat, stirring frequently, until

the gelling point is reached.


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Test for the gelling point

Temperature test

Use a jelly or candy thermometer and boil until

jam reaches the right temperature for your

altitude

If your altitude is Boil until mixture

reaches

Sea level 220 degrees F

1,000 feet 218 degrees F

2,000 feet 216 degrees


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Refrigerator test

Remove all the jam from the heat and pour a

small amount of boiling jam on a cold plate.

Put the plate in the freezing compartment of a

refrigerator for a few minutes.

If the jam gels, it is thick enough.


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Sheet or spoon test

Dip a cool metal spoon into the boiling jelly

mixture.

Raise the spoon out of the steam, about 12 inches

above the pan.

Turn the spoon so the liquid runs off the side.

The jelly is done when the syrup forms two dropsthat flow together and sheet or hang off the edge

of the spoon.


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When mixture first boils,

drops are light and syrupy.

As mixture continues to

boil, drops become heavier

and drop off spoon two at

a time.

When two drops

form together and

"sheet" off thespoon, the gelling

point has been

reached.


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Overcooking jam and jelly can break down

pectin and prevent proper gelling.

Always make only one batch at a time. Making

more than one batch at a time (doubling or

tripling the recipe) often results in soft gels.

Stir constantly while cooking to prevent

burning.

Remember that recipes are developed for

specific jar sizes.

Using larger jars may cause excessively soft sweet

spreads.


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Pasteurization

mild heating treatment at temperaturesup to 100C

causes only a slight decrease in taste and

nutritional value Inactivates enzymes

Pasteurized products therefore spoil

faster than sterilized products


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Pasteurization

products should be stored in

temperatures below 20C

The more acid or sugar contained in apasteurized product, the longer it will

stay good because the remaining micro-

organisms do not have a chance todevelop


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Heat container in a pan of hot water

It is important that the lid of a glass jar fit well, donot close the lid tightly

some air should be allowed to escape during heating

Close the lid tightly immediately after removingthe jar from the pan.

As the product cools, a vacuum will developwithin the container.

In this way the food has no chance of coming incontact with the air and becoming contaminated.


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Start monitoring the heating time as soon as

the water has reached the recommended

temperature listed in the appendix.

Remove the bottles or tins as soon as the

recommended time has elapsed and allow

them to cool.


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