Transcript ******* 1 - European Commission

Methods of identification of brix
and fruit in natural juice
Charalampos Proestos,
Lecturer in Food Chemistry
Department of Chemistry,
National and
Kapodistrian University of Athens
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Legislation
1. EU: The new Fruit Juice 
Directive (2012/12)
Relating to fruit juices and certain 
similar products intended for
human consumption
Until 28 April 2015 products placed 
on the market or labeled before 28
October 2013 can be sold.
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Legislation
The composition of fruit juices, 
concentrated fruit juices, dehydrated
fruit juices and fruit nectars, their
reserved names, their manufacture
and labelling characteristics are
subject to specific Community rules
under Directive 2001/112/EC
amended in August 2009 by the 
Commission Directive2009/106/EC
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Legislation
2.CODEX GENERAL STANDARD FOR F 
RUIT JUICES AND NECTARS.
(CODEX STAN247-2005).
3. Association of the Industry of Juices 
and Nectars from fruits and vegetables
(AIJN) – EUROPEAN FRUIT JUICE
ASSOCIATION REFERENCE
GUIDELINES (RF) + Code of Practice
for evaluation of quality and authenticity
of juices.
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Analytical criteria for authentic
juices
commercial standards have existed 
for a number of years in countries
such as France, Germany, and the
Netherlands
German Fruit Juice Industry guide 
values, known as the RSK values
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Adultaration-Current issues
(1) overdilution of juices with water 
(2) use of cheaper solid ingredients 
(particularly sugars)
(3) blending of cheaper with more 
expensive juices.
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Overdilution of juices with
water
Application of a minimum solids 
content (measured in
degrees Brix). They normally apply to 
juices prepared by adding water to
concentrate
and not to ‘(NFC) not from 
concentrate’ products.
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Use of cheaper solid ingredients
(particularly sugars)
by far the most common
E.g. apple juice will normally contain
around 11% by weight of solids.
90% of these solids are
carbohydrates – sucrose, dextrose
and fructose predominate.
Addition of cheaper sources of
carbohydrates can be used to
‘stretch’ apple juice
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



Continue..
One obvious means of concealing 
added sugar is to increase acidity
with added organic acids.
commercial malic acid was used that 
contained both D- and L- forms of the
acid
pure fruit juices only contain the L- 
form.
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Blending of cheaper with more
expensive juices.
A cheaper juice can be used to 
adulterate a more expensive one
E.g. elderberry juice can be used to 
extend strawberry or raspberry juice
Juice authenticity 
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Definitions (Directive 12/2012)
(a) Fruit juice 
The fermentable but unfermented 
product obtained from the edible part
of fruit which is sound and ripe, fresh
or preserved by chilling or freezing of
one or more kinds mixed together
having the characteristic colour,
flavour and taste typical of the juice
of the fruit from which it comes.
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(b) Fruit juice from concentrate
The product obtained by 
reconstituting concentrated fruit juice
with potable water that meets the
criteria set out in Council Directive
98/83/EC of 3 November 1998 on the
quality of water intended for human
consumption
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SS and Brix
The soluble solids content of the 
finished product shall meet the
minimum Brix level for reconstituted
juice specified in Annex V.
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ANNEX V
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Annex 5 continue..
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FJFC - Definitions continue..
If a juice from concentrate is manufactured from a fruit not
mentioned in Annex V, the minimum Brix level of the
reconstituted juice shall be the Brix level of the juice as
extracted from the fruit used to make the concentrate.
Concentrated fruit juice
The product obtained from fruit juice of one or more fruit
species by the physical removal of a specific proportion
of the water content. Where the product is intended for direct
consumption, the removal shall be at least 50 % of
the water content.
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3. Water extracted fruit juice
The product obtained by diffusion with water of:
— pulpy whole fruit whose juice cannot be extracted by any
physical means, or
— dehydrated whole fruit.
4. Dehydrated/powdered fruit juice
The product obtained from fruit juice of one or more fruit species
by the physical removal of virtually all the water content.
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5. Fruit nectar
The fermentable but unfermented product which:
— is obtained by adding water with or without the addition of
sugars and/or honey to the products defined in
points 1 to 4 to fruit purée and/or to concentrated fruit purée
and/or to a mixture of those products, and
— meets the requirements of Annex IV.
Flavour, pulp and cells obtained by suitable physical means from
the same species of fruit may be restored to the
fruit nectar.
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Annex IV
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Continue..
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More Annex IV
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Definitions of Raw Materials
(1) Fruit
All fruits. For the purposes of this Directive, tomatoes are also
considered as fruit.
(2) Fruit purée
The fermentable but unfermented product obtained by suitable
physical processes such as sieving, grinding, milling
the edible part of whole or peeled fruit without removing the
juice.
(3) Concentrated fruit purée
The product obtained from fruit purée by the physical removal of
a specific proportion of its water content.
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Continue..
(4) Flavour
(5) Sugars
— sugars as defined by Council Directive 2001/111/EC of 20
December 2001 relating to certain sugars intended for
human consumption,
— fructose syrup,
— sugars derived from fruits.
(6) Honey
The product defined by Council Directive 2001/110/EC of 20
December 2001 relating to honey
(7) Pulp or cells
The products obtained from the edible parts of fruit of the same
species without removing the juice. Furthermore, for
citrus fruit, pulp or cells are the juice sacs obtained from the
endocarp.
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Estimation of juice or fruit
content
1. assessing the ash content,
2. levels of potassium ions,
3. phosphorous content,
4. total level of free nitrogen by
measuring the formol value,
5.levels of specific amino acids and a
range of other
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Brix measurement in juices
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Refractometers
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Testing the Amount Of Juice, The Acid
And The Sugar Levels In Citrus Fruit
Testing Fruit
Percent Juice Content: Juice content is an important measure
of internal quality. Under or over-ripe fruit tend to be less juicy,
which directly affects eating quality. The juice content is
determined by weighing components of the whole fruit and the
juice.
- Brix (total soluble solids): In the citrus industry this is a
measure of the total soluble solids in the juice. These soluble
solids are primarily sugars; sucrose, fructose, and glucose. Citric
acid and minerals in the juice also contribute to the soluble
solids. Brix is reported as "degrees Brix" and is equivalent to
percentage. For example, a juice which is 12 degrees Brix has
12% total soluble solids. The National standards state the
minimum brix sugar/ acid ratio.
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Continue
Acid (titratable acidity): This is a measure of the total acid
present in a juice. The predominant acid naturally occurring in
orange juice is citric acid. There are also small amounts of malic
acid and tartaric acid present.
The amount of acid present in the juice is reported as percent citric
acid. It needs to be noted that the total acid cannot be measured
by pH because the acids concerned are “weak acids” and not
completely ionized. The acid content must be measured using a
titration with sodium hydroxide.
Sodium benzoate determination!!!
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Determining soluble solids
content (% sugar or °Brix)
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Continue..
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Determination of total acidity
The acidity of natural fruit juices is the result
mainly of their content of various organic
acids. For example, most fruits contain the
tricarboxylic acid, citric acid, whereas
grapes are rich in tartaric acid & peaches,
apricots & plums in malic acids. Both
tartaric & malic acids are dicaroxylic acids.
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Tartaric acid MW=150.09
malic acid
MW=134.09
citric acid
MW=192.43
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The acidity of fruit juice may be
determined by simple direct titration
with 0.1M sodium hydroxide, using
phenolphthalein (ph.ph) as an
indicator.
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Method :
1. Weight 10g of sample in conical flask
& add 50ml distilled water
2. Titrate using 0.1M NaOH &
phenolphthalein (ph.ph) as indicator
3- Calculate the total acidity of your
fruit juice
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citric acid= 0.1 x vol.of NaOH(ml) x
10-³ x 192.43/3
Total acidity= wt of acid/wt of sample
*100
Normal range for citric
acid =
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0.39-1.1
Example
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Determining sugar/acid ratio
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Industry Standards
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Determination of sodium
benzoate
Sodium benzoate (C6H5COO Na ,MW=144
) is a commonly used preservative which
is added to fruit juices to prevent the
growth of microorganisms. When added
in high conc., it affects the taste of
juice.
Sodium benzoate is usually permitted at a
conc. Of up to 1.3g/l of juice.
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The benzoate anion is not soluble in
non-polar solvents because of its
negative charge. However, in acid
solution, benzoic acid is formed.
This is neutral & quite non-polar.
Moreover, it is soluble in non-polar
solvents, into which it may be
extracted at acidic PH, i.e. well
below the pka of the carboxyl
group , which is 4.20 .
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In an experiment , benzoic acid is
extracted into chloroform, which is
then removed by evaporation.
After dissolving the residue in
50% (v/v) neutralized ethanol,
the benzoic acid is titrated with
0.05M sodium hydroxide, using
phenolphthalein as an indicator.
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Method:
Weight 10g of sample into a graduated .1
flask & add 1ml of 10% NaOH solution & 12
g NaCl. Add sufficient water to bring the
vol. up to about 50ml & let it stand for 30
min. with frequent shaking .
2- Add drops of ph.ph (the color will change) ,
add drops of HCL until the color change (or
disappear), then add excess 3 ml HCL
3. Transfer into a separatory funnel
4. Add 25ml of chloroform
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4. let it sand for 30min with frequent shaking.
5. Transfer 12.5ml of the chloroform layer
(low layer) into a conical flask & evaporate
off the chloroform on a steam bath
6. Add 50ml of 50%ethanol solution
7. Titrate with 0.05M NaOH using
phenolphthalein(ph.ph) as indicator
8. Calculate the amount of sodium benzoate in
the sample.
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1ml of 0.05M NaOH =0.0072 sodium benzoate.
Ttitre ml of NaOH = x
Wt of sodium benzoate(x) = ml * 0.0072
%of sodium benzoate= wt sodium benzoate/
wt of sample *100
Normal range not exceed 0.13%
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Determination of total solids
Remnants of pulp & other solids are
easily determined gravimetrically,
after evaporation of water from a known
weight of sample.
The solid present in juice include sugar
, organic acid & pectins
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Method:
1-Weight a dry dish
2-Add 15ml of juice & weight
3-Place the dish & its content on a
boiling water bath & evaporate to
dryness
4-Place the dish in an oven for 2hrs.
5-Put the dish in descicator to cool %
weight.
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%total solid=( wt of beaker after
heating_ wt of empty beaker *100)/
Wt of sample(g)
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Code of Practice for
evaluation of fruit juices
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Any Questions?
[email protected]
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