GID 416 SHELF LIFE OF FOODS STABILITY AND SHELF LIFE EVALUATION OF FRUIT JUICES

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GID 416 SHELF LIFE OF FOODSSTABILITY AND SHELF
LIFE EVALUATION OF FRUIT JUICES

• Damla Dilek Senel
• Pinar Bozaci
• A.Erkan Akay
• M.Burcu Kizilöz

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What is fruit juice?

• Juices obtained by mechanical processes or
  using concentrates of fruits
• -unfermented but fermentable
• -pulpy
• -turbid or clear
• -carry the specific aroma, color and
  flavour properties
• of the fruit
• ESSENTIAL COMPOSITION
• Soluble solids
  Concentrates
• Sugars
  Acids
• Ethanol
  Regulators

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Quality Factors

• Hygiene
• (a) shall be free from microorganisms
  capable of development under normal conditions
  of storage.
• (b) shall not contain any substances
  originating from microorganisms in amounts which
  may represent a hazard to health.

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Quality Factors

• Weights and Mesures
• Minimum Fill
• The juice shall occupy not less than 90 v/v
  of the water capacity of the container.
• The water capacity of the container is the
  volume of distilled water at 20 C which the
  sealed container will hold when completely
  filled.

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Quality Factors

• Marking or Labelling
• The name of the product
  
• "x juice" "pulpy x juice"
• Quantity of added sugar or sugars exceeds 15
  g/kg
• "sweetened"
• In the case of a fruit juice made from
  concentrate
• "x juice made from concentrated x juice"
• List of Ingredients
• except that water and volatiles added for
  reconstitution of the juice

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• No fruit or fruit juice may be represented
  pictorially on the label except the species of
  fruit present or the juices therefrom.
• No claim shall be made in respect of "Vitamin C"
  nor shall the term "Vitamin C" appear on the
  label unless the food contains such quantity of
  "Vitamin C" as would be accepted by national
  authorities in the country in which the food is
  sold, as warranting such claim or the use of such
  term.
• Where the food contains more than 2 g/kg of
  carbon dioxide the term "carbonated" shall appear
  in close proximity to the name of the food and
  carbon dioxide shall also be declared in the list
  of ingredients.
• Where the fruit juice requires to be kept under
  conditions of refrigeration, there shall be
  information for keeping and, if necessary,
  thawing of the food.
• Codex General Standard for the Labelling of
  Prepackaged Foods

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SHELF LIFE AND SENSORY EVALUATION OF JUICES

• Reasons for shelf life studies
• To determine the affect of a new component or
  additive that is added to formulation to the
  shelf life
• To ensure propriety of a production facility of a
  product to the predicted shelf life.
• To monitor the stability of a product in variety
  of storing conditions in case of global
  marketing.
• To control the propriety of new technics and
  applications for production.
• To determine the changes in sensory quality of a
  product during shelf life and precautions for
  consumer handling.
• To ensure the similarity of first production
  facilities and the trial applications done in
  labaratory or pilot production plant.
• To control the product in the name of legal
  standarts.
• To determine the form and contents of label.
• To control the propriety of product for all
  consumers, and supply the continuity of demand.
• To supply the shelf life long enough to make the
  product sale in the supermarkets and retail
  stores in which large stocks are handled.
• To assest the risks occured during the studies
  aiming to decrease the costs of formulation,
  preservation and production.

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CHANGES DURING THE SHELF LIFE OF FRUIT JUICES

• colour changes and browning
• aroma changes
• vitamin losses
• changes in mineral material
• microbiological spoilage

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• Shelf life determining factors are
• Raw materials
• Formulation
• Processes
• Hygiene
• Packaging
• Storage and distribution
• Product display conditions
• Consumer handling

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Formulation

• ? Hydrolysis of sugars and artificial sweeteners
• ? Maillard reactions during the end period of
  shelf life
• ? Degredation of ascorbic acids
• result in darkening of
  product color.
• ? Preservatives such as SO2 may be included in
  formulation in order to prolong the shelf life
  inhibiting these darkening reactions.
• ?Addition of acidulants, such as citric acid,
  citric acid combined with ascorbic acid, to
  either pasteurised or fresh juice support the
  appeareance of desired color
• ? Potassium sorbate may also be used due to its
  antimicrobial action but sodium benzoate and high
  levels of potassium sorbate are not preferred due
  to their accelerating activity of browning
  reactions

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Packaging material

• Package is a barrier for light and oxygen.
• Glass packages like bottles ?good barriers for
  oxidation
• Increase in the oxidation rate of residual
  oxygen remained in the headspace, due to light
  permeation.
• Metal or isolated boards ? To prevent light
  penetration
• Nitrogenation during package closure ? oxygen is
  flushed out
• Carbonation ? removal of other gases
• Tetra-pak, cartoon or dark coloured plastic cans
  ?
• Preservation from oxidative affects of
  ultra-violet lights

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Storage Temperature

• Oxidative and hydrolysis reactions accelerates in
  presence of light by increasing storage
  temperature.
• In uncontrolled situations , the difference of
  temperature between day and night ?acceleration
  of reactions
• The ideal conditions for storage are 4-10O C.
• Other factors affecting shelf life
• hygiene of process and equipments,
• usage of proper raw materials,
• process control units

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SHELF LIFE TESTING

• sensory analysis ?
• followed by some
• ? chemical analysis
• Colour degradation may be monitored by
  trained panels and also by colorimetric
  measurements.
• Combined sensory and analytic methods for
  oxidation of flavours reveal beter results.
• Gas cramatography and GC coupled mass
  spectroscopy are used following the sensory
  analysis

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SHELF LIFE TESTING

• Methods suggested for the control of shelf
  life and product quality during the shelf
  life
• Difference tests, to determine the appeareance
  times of sensory changes
• Descriptive and defining analysis, to determine
  the limits of differences of different samples
• Consumer acceptance tests, to determine the
  certain shelf life.

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