Minimal processing of fruits and vegetables

1. Minimal processing of fruits and
vegetables
• Minimal processing of fruits and vegetables (MPFV) is the process
of physically altering fresh produce to increase its functionality
without changing its fresh properties.
• They are also called ready-to-use, fresh-cut or pre-cut produce
• The process involves sorting, cleaning, washing, peeling, trimming,
and deseeding, and cutting the produce to a specific size.
• MPFV must be safe, wholesome, nutritious, and have the same
sensory properties as freshly prepared produce, such as;
 Aroma
 Taste
 Texture, and visual appeal

2. • Over the last few years, global demand for minimally
processed fruits & vegetables increased, this is so beacause of
the following reasons;
1. A growing focus on health, which includes the
consumption of fresh fruits &vegetables
2. The increased preference for convenience.
3. To the extent possible, consumers want healthy products
for their meals, available at a good value, convenient,
safe, and with good quality

3. Flow chart for preparation of minimal
processed fruits and vegetables
Sorting for defects
Packaging and labelling
Harvesting
Cutting to specific size
Receiving
Cooling
Washing and
disinfection
Peeling, deseeding
and Trimming
dipping
draying
Antimicrobial
And
Antibrowning
agents
Storage & Distribution

4. Harvesting
• During the harvesting, the following points must be
kept into consideration.
• Well trained person must be engaged in the selection
of fresh produce of sound quality, so as to avoid its
damage and contamination during handing.
• Handlers must ensure to use of clean and hygienic
equipment's such as sharp harvesting knives, bags and
padded boxes during fresh-cut processing.
• Mechanical harvesters are used in large operations
• Workers must wear clean clothes and observe sanitary
measures.

6. 2.Receiving at the processing facility
• The receiving point for fresh fruits and vegetables in
a fresh-cut processing plant is a key quality check-
point that should be monitored closely.
• Employees receiving produce should check for
defects and make note of any problems that can be
relayed to the grower.
• At this point a decision can be made on whether or
not to process the produce.

7. • Large processing operations have a list of quality
parameters and measurements that are recorded when
fresh produce arrives at the processing facility.
• An inventory of stocks begins with receipt of the
produce.
• In addition, field number, harvest crew, vehicle
registration and other information also need to be
recorded.
• This information would really help to trace it back to
the field in the event of a food crisis.
• Large processing facilities usually have an enclosed,
refrigerated dock facility for receiving produce.

8. 3.Pre-cooling
• Ideally, the purpose of precooling is to remove field heat prior to
storage or processing so as to extend the shelf-life of the final fresh-
cut produce. It can
• be achieved by using a number of technologies such as chilled
water baths, forced air cooling, vacuum cooling and packing with
ice-water mixtures.
• These expensive technologies are not really useful for small
produce.
• The temperature must be kept such that it would not cause any
chilling injury of the fruits and vegetables.
• Intact fresh produce should be segregated from the ones that have
been pre-cut and washed, in a small cold storage area to avoid cross
contamination between them.
• In addition, staff should use a First-in, First-out (FIFO) policy for
managing stock rotation.

9. 4. Washing and disinfection
• Washing is really essential operation in MPFV and need
to be carried out as soon possible.
• The main function of washing is to remove damaged
tissues, which normally is carried out with water flumes
and tanks prior to cutting and trimming.
Water flume for washing and transporting fruit in a large packing
house

10. • Potable water is a key requirement for washing in order to
preclude the transfer of contamination from water to the
produce.
• For the issue of water conservation, many large fresh-cut
processing operations treat and recycle this used water of
precious commodity.
• But it increases the hazard of microorganisms. Thereby,
recycled wash water can be treated with antimicrobial agent
like HOCl for maintaining its quality.
Methods used for washing purposes of MPFV.
(a).Small scale operation; washing can be carried out in a sink or
under a tap with continuously circulating wash water through a
filter.
• In most cases, two tanks are used for washing (first tank- for
removal of heavy soiling and subsequent cleaner tanks with
chlorinated water – for final washing).

11. (b). Large fresh-cut processing plants; they make use
of continuous washers .
• In such situations, a moving conveyor picks up the
produce and carries it under powerful sprays of
water. Recirculation through a filter reduces the
overall water consumption.
• The temperature, contact time, pH and chlorine
concentration should be monitored for their
effectiveness during washing.
• The measurement of ORP (oxidation reduction
potential) can also be used to monitor the
disinfectant level in wash water.

12. Continuous washing of pre-cut lettuce

13. • For vegetables, following parameters may be
used for the wash water: temperature (0-5°C),
pH (4.5-5.5), chlorine concentration (50-100
ppm), ORP (650-750 ppm).
• During the washing process any defective
produce must be removed and discarded.

14. 5.Peeling, trimming and deseeding
• Several kinds of equipments being used for peeling,
trimming and deseeding of MPFV which includes
knives for small scale, abrasive peelers and automatic
trimmers for large scale.
• Automated peelers with abrasive rollers are used in
some large processing plants for peeling potatoes and
carrots.
• Machinery has been designed for specific high volume
crops, including the use of high pressure air and lye
and steam for peeling.
• However, for small operations, hand peeling is
adequate

15. 6. Cutting operations
• The cutting operation may include various operations
such as chopping, slicing, shredding, peeling, dicing or
sectioning.
• These operations are done mainly by hands in many
small-scale operations. The cutting dimensions are also
needed to be considered.
• Good Hygienic Practice (GHP) must be strictly observed
during cutting operations, to avoid contaminations.
• A proper attention should be given to employees. They
must wear protective clothing including gloves, aprons
and hair nets and should be well trained

16. Workers preparing and sorting cut fruit

17. 7. Sorting for defects
• The importance of sorting is to improve the uniformity
of the finished fresh-cut product and also to enhance
the shelf-life, by separation of defective products.
8 Rinsing of pre-cut fruits and vegetables
• It is recommended that only water of the highest
quality be used for the final rinse of pre-cut fruits and
vegetables.
• Many use chloride as disinfectant along with acid in
order to maintain a pH range of 4.5-5.5 for proper
action of chloride.
• The temperature of fresh cut is reduced with the help
of ice in order to ensure that it is not a source of
contamination.

18. 9 Dipping ;
• Produce can be optionally dipped in a solution of an
acidulant/antioxidant blend consisting of a combination of
ascorbic acid/citric acid for example, or in an anti-softening
agent such as calcium chloride.
10 Drying ;
• After dipping, there is need to remove the liquid associated
with the produce, prior to packaging, otherwise, it would
create a mould and other microbial growth and texture
deterioration problems.
• Some manual and mechanical methods employed for water
removal from produce includes:
 conveyor shakers (use of the vibration)
 Air drying (use of forced air or polar wind)
 Spin-drying baskets (use of centrifugation force).

19. 11 Packaging and labeling
• Packaging facilitates the delivery of fresh-cut products of good
quality to the consumer and also protects products from physical
damage and prevents physical and microbiological contamination.
• Various techniques are used for packaging of MPFV such as MAP,
CAP.
• Packaging formats for fresh-cut fruits and vegetables (Plate 5)
includes;
 Plastic bags
 Thermoformed containers with film overwraps
 Rigid plastic containers.
• In addition, other packaging films used includes perforated, thin,
low density polyethylene (LDPE), monolayer polyvinylchloride (PVC)
and ethylene vinyl acetate.

20. Examples of packaging used for fresh-cut
fruits and vegetables

21. Fresh cut fruits and vegetables

22. 1. Produce for the fresh cut processing
• Fresh-cut fruits:
 melon chunks and slices
 Cored and sliced pineapple
 Apple wedges treated with antibrowning preservatives;
 Peeled citrus fruits and segments;
 De-capped strawberry; de-stemmed and washed grapes; sliced kiwifruits, and fruit salads, etc.
• Fresh-cut vegetables:
 Shredded lettuce
 Shredded and diced cabbage
 Washed and trimmed spinach
 Peeled “baby” carrots
 Cauliflower and broccoli florets,
 Sliced or diced tomatoes
 Peeled and sliced potatoes
 Snapped green beans
 Trimmed green onions, cleaned and
 Diced onions, and mixed salads, etc. Fresh-cut herbs are also marketed widely.

23. 2. Treatments to ensure safety

24. 3. Additives to preserve quality
• The marketing of minimally processed fruits and vegetables is
limited by a short shelf life and rapid deterioration of their
components due to tissue damage as a result of processing, e.g.
washing or cutting, and the microbial growth.
• They can be preserved by using various techniques such as
refrigeration, biopreservation, additive, mild heat treatments,
disinfectants, reduction of water, microwave processing, chemical
preservatives.
• Additives are substances added in small quantities during processing to
achieve specific benefits Chemical post-cutting treatments Wounding
and ethylene can initiate phenolic metabolism that ultimately leads
to browning in fresh-cut tissue. Control of discoloration (pinking,
reddening or blackening) or browning at cut surfaces is, therefore, a
critical issue for fresh-cut producers. Outlined below are a number
of strategies that may be used to reduce cut-surface discoloration
and maintain the textural integrity of fresh-cut produce.

25. • 5.4.1.1 Acidification: PPO most effectively catalyses
cut-surface discoloration at a neutral pH (around pH
7.0). Browning can, therefore, be slowed by dipping
products in mildly acidic food grade solutions of acetic,
ascorbic, citric, tartaric, fumaric or phosphoric acid.
Quite often, combinations of acids (for example
combinations of ascorbic and citric acid) are more
effective than the use of acids individually. The
enzymatic browning of fresh-cut apples, cabbage,
endive, lettuce, melon and pears is avoided by dipping
in solution of ascorbate and citric acid (Raju et al .,
2000). Acidification, treatments with ascorbic acid
(0.2%)