The Control of Enzymatic Browning in Fresh

The Control of Enzymatic
Browning in Fresh-Cut Produce
Simon Matthews
Mantrose Haeuser Inc
Industrial
Cosmetics
Confectionery
Pharmaceutical
Agriculture
Semperfresh® - Pre Harvest Treatment
on cherries to prevent rain-induced skin
cracking
Semperfresh® - Post Harvest
Treatments for fruit to delay ripening
in transit and storage
Coatings to extend shelf life and
maintain quality in fresh cut and
minimally processed fresh produce.
E.g. Natureseal® - Vitamins and mineral
mixtures; cellulosics
Physical Responses
• Mechanical shock to tissue (bruises,
cracks, fractures)
• Loss of structural integrity
• Entry for contamination
• Accelerates water loss
• Substrate for microbes
• Alter (reduce or enhance) gas diffusion
• Surface debris changes appearance
• White blush formation
Physiological Responses
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Elevated ethylene production
Wound response
Membrane depolarization
Elevated respiration
Oxidative reactions
Induction of enzymes
Altered phenolic metabolism / wound healing
Compositional changes
Reduced carbohydrates, organic acids & ascorbic
acid
Toughening, softening
Loss of flavor, aroma
Browning
Simplified schematic enzymatic (polyphenol oxidase) browning
Factors Influencing Browning
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Type of product & variety
Growing conditions
Maturity of crop (picking date)
Storage conditions
Concentration of oxygen
Processing method
Sulphiting Agents
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Sulphur Dioxide
Sodium Metabisulphite
Sodium Sulphite
Sodium Bisulphite
Potassium Bisulphate
Potassium Metabisulphate
Non-Sulphite Anti-Browning
Agents
• Antioxidants (reducing agents)
– Ascorbic Acid
– Ascorbyl Palmitate
– Ascorbic Acid Phosphate
– Glutathione
– Adsorbed Tocopherol
– L-Cysteine
Non-Sulphite Anti-Browning
Agents
• Chelating Agents
– EDTA
– Sorbic Acid
– Sodium Pyrophosphate
– Sodium Polyphosphate
– Citric Acid
Non-Sulphite Anti-Browning
Agents
• Acidulants
– Citric Acid
– Malic Acid
– Tartaric Acid
– Phosphoric Acid
PPO Inhibitors
• 4-Hexylresorcinol
• Aromatic Carboxylic Acids
• Sodium Chloride
• Calcium Chloride
• (and other anions)
• Cyclodextrins
• Co-developed by USDA
• Powder blends of vitamins & minerals
• Sulphite-free
• Prevent oxidative browning
• Maintain texture
• Minimise water loss
• Does not impart flavour, colour or odour
• Easy to apply by dipping or spraying
Water Loss from Bramley Apples
Ascorbic and citric
acid dip
P e rc e n ta g e L o s s
10
8
6
4
2
0
5 % Natureseal
AS1 dip
0
50
100
Time Hours
150
200
5.3 % Natureseal
AS5 dip
Main Applications
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Apples
Pears
Carrots
Celery
Rhubarb
Sweet Potato
Swede / Turnip
Belgian Endive
(Chicory)
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Melon
Pineapple
Mango
Limes
Stone Fruit
Snack Apple Products
UK and Europe
Sanitation
• Strict food safety & cleaning
procedures
• Chlorine and alternatives
–(viz. Tsunami, Catallix, Citrox,
Ozone etc.)
• Must maintain cold-chain
• Avoid bruising
Coring and Slicing
Removal and segregation of core
tissue
Sharp corer and cutting blades
Cleaning / sanitising equipment
Rinsing and sanitising slices
Apply Natureseal as soon as possible
after slicing
Dipping Natureseal
Dipping
Economical use of Natureseal
Ensures complete immersion of
fruit pieces
Natureseal solution can be
chilled
Simple to use and clean
Concentration Meter
Micro Filtration of
Natureseal Solution
Packaging
Packing
• Ensure aerobic atmosphere
throughout shelf life
• Avoid excessive build up of
carbon dioxide
– Blown packs
– Fermentation (Flavours)
– Yeast growth
– Reduce weight loss
• Increases shelf life
Summary
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Natureseal products
Patented powder blends
Effective on wide range of produce
Extends shelf life (except microbial)
With apples up to 21 days
Does not affect taste