Simon Matthews

The Control of Enzymatic Browning in Fresh-Cut Produce

Mantrose Haeuser Inc

Industrial

PharmaceuticalConfectionery

Cosmetics

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

• 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

Physiological Responses

Simplified schematic enzymatic (polyphenol oxidase) browning

Browning

Factors Influencing Browning

• Type of product & variety• Growing conditions• Maturity of crop (picking date)• Storage conditions• Concentration of oxygen • Processing method

Sulphiting Agents

• 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

• Acidulants

– Citric Acid– Malic Acid– Tartaric Acid– Phosphoric Acid

Non-Sulphite Anti-Browning Agents

• 4-Hexylresorcinol• Aromatic Carboxylic Acids

• Sodium Chloride• Calcium Chloride• (and other anions)

• Cyclodextrins

PPO Inhibitors

• 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

02468

10

0 50 100 150 200

Time Hours

Perc

enta

geLo

ssAscorbic and citricacid dip

5 % NaturesealAS1 dip

5.3 % NaturesealAS5 dip

Main Applications

• Apples• Pears• Carrots• Celery• Rhubarb• Sweet Potato• Swede / Turnip• Belgian Endive

(Chicory)

• 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

• 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

Packing

Summary

• 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