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Food manufacture
New developments in food processing
In the core strand, Food manufacture, you learn about preservation processes. In the optional strand, Contemporary food issues: Marketplace, you learn about emerging technology in food production and manufacturing. This tutorial explores new non-thermal methods of preservation.
Outcomes
This material addresses aspects of the following syllabus outcome:
H1.1 A student
explains manufacturing processes and technologies used in the
production of food products.
H 3.2
A student independently investigates contemporary food issues.
Extract from Stage 6 Food Technology Syllabus © Board of Studies NSW 1999.
Preservation
Preservation of food has always been a key way to extend the shelf life of foods. However, each of the traditional techniques has its drawbacks, especially in relation to consumer acceptance. Consumers value "perceived freshness, attractive sensory attributes, high levels of food safety, health benefits and convenience." (Pearce et al, 2002: 49)
Non-thermal technologies are offering new opportunities for food manufacturers, they include:
- high pressure processing (HPP)
- ultrasonics
- ultraviolet light
- pulsed electric field (PEF).
As yet only HPP and ultraviolet light are in commercial use.
High pressure processing (HPP)
High pressure processing
(HPP), also referred to as High hydrostatic pressure processing
and Ultra high pressure processing (UHP), involves the application
of very high pressures (up to 6 000 times atmospheric pressure)
to pre-packaged or bulk liquid or solid foods, in a hydrostatic
press. Food is processed in batches by manually loading a basket,
which is lowered into a vessel filled with water, to which pressure
is then applied. In food systems, vegetative bacterial cells,
yeasts, moulds and many enzymes can be inactivated by HPP. While
the structure of some food products can be altered by the application
of HPP, it generally has minimal effect on texture, the vitamins,
or on the compounds that impart flavours and colour to foods.
(Pearce et al, 2002: 50) Click
here 
for an image
of HPP equipment.
HPP may be an alternative to heat processing such as pasteurisation or the use of chemicals. This technology has such little effect on quality the food can be marketed as fresh, which increases market opportunities. HPP is another way of value adding.
The economic benefits of value adding food can be seen in the following example:
... a single kilogram of raw vegetable exported from Australia was found to be $1.47, compared with $3.40 for a kilogram of processed product such as shelf-stable vegetable juice. (Pearce et al, 2002: 50)
HPP is currently at the research stage in Australia, however it is being used for some foods in the UK, Japan, US and Europe. The following are some of the products on the market that have been treated with HPP:
- jams
- jellies
- oysters
- processed meat products
- fruit juices.
Benefits of HPP
The benefits of HPP include:
- quality and flavour improvements
- food safety levels are similar to pasteurisation
- nutrient retention is improved
- shelf life of existing products is extended
- 'new' product textures are created
- there is uniform cooking regardless of shape and size
- it can be used in continuous processing
- food can be processed in the package
- freezing is improved due
to small ice crystal formation.
(Adapted from Table 1: Overview of joint CSIRO (Food Science Australia) and TNO Food Science and Nutrition non-thermal processing capabilities and related technology benefits in Pearce et al, 2002: 66)
Innovative Foods Centre (IFC)
The Innovative
Foods Centre (IFC)
has been opened in Melbourne to research the technology needed
to produce novel "fresh" foods.
Equipment available in the Centre will include High Pressure Processing equipment ... ultrasonics in six different implementations of frequency, scale and power ... pulsed electric field and ultraviolet light equipment. (Pearce et al, 2002: 50)
Activity 1
- Identify trends in the marketplace that may be more easily achieved by using technology such as HPP.
- Select one of the foods being processed
by HPP in other parts of the world and analyse the effect of
traditional preservation techniques on flavour, texture and nutrient
retention of that food. For example, canned and bottled oysters.
Does there appear to be a need to use a non-thermal process such as HPP?
What benefits could you see for using HPP for that food?
References
Pearce, R, Marcure, J & Versteeg, K 2002, "Pressure mounts on food processing", Global Supermarket, Vol. 6, No. 3, pp.4950, 6667.
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