Transcript Applications of Biotechnological Processes

Applications of
Biotechnological Processes
The Food Industry and
Fermentation
Dairy Products
Yeast Extract Products
Fruit Produce
Dairy Products
Microbes are used to make cheese, butter,
yoghurt and sour cream.
Traditional Method:
Products were produced through the
action of indigenous bacteria present in
milk.
Modern Method
Milk is pasteurised to ensure safety for
human consumption (kills indigenous
bacteria).
Microbial cultures are added to the milk.
Bacteria convert the lactose in milk to
lactic acid (lower pH). Bacteria are
referred to as “lactic acid bacteria” e.g.
Lactobacillus or Bifidobacterium
 A lowering of the pH results in the protein in milk
clotting and a release of flavours and aromas. A
lower pH also reduces the likelihood of
contamination.
 The specific bacteria used will determine specific
properties, textures and aromas in the final
product. Sometimes a second inoculum of
bacteria is added to create the final, desired
product
Functional Foods
Functional foods are those which provide
health benefits beyond basic nutrition.
e.g. novel fermented drinks (also known as
probiotics) provide several health
benefits:
 Probiotics contain “live” cultures that can reestablish themselves in our gut flora to return the
individual to full health. They often do this by
competing with disease causing gut flora for
nutrients and by producing chemicals that will
inhibit pathogen growth.
Examples: Bio-yoghurts
 Some probiotics can shorten the duration of
infant viral diarrhoea
 Probiotic bacteria are able to establish themselves in the
gut and synthesise vitamins. These vitamins can be
absorbed through the individuals gut wall and taken up
by the bloodstream.
 Probiotics and nutraceuticals are believed to have some
anti-cancer properties, have the ability to reduce
cholesterol and improve an individual’s intolerance to
lactose.
(nutraceuticals- food ingredients that provide health
benefits)
Yeast Extract Products
 Yeast is used to produce alcoholic drinks, make yeast
extracts (found in Bovril and Marmite) and to make food
flavourings.
 Yeasts have a useful property known as autolysis.
 This is a process that results in the yeast producing
enzymes that degrade itself, thus releasing particular
flavours.
Example: peptidase production and subsequent protein
hydrolysis will create “beef flavour”
The flavour released depends on the
enzyme, the stage in the yeast cell cycle
and the age of the culture.
Yeast flavourings are found in crisps,
soups and other packet foods
Fruit Produce
Fruit is used to make fruit juices, enzymes are
added in their production to clarify the juice.
 Pectinases
are produced by fungi
Pectin holds/binds cell walls together, it is extracted
during the fruit pressing stage in juice making.
Pectin is highly viscous and can lead to problems with
clarification and juice filtration
Adding pectinase hydrolyses the pectin polymer to
individual carbohydrate units
Arabanase
Araban is also a polymer found in cell walls, it is
extracted during the fruit pressing stage in juice
making.
It creates a haze in the pressed juice.
Adding arabanase removes the hase.
Amylases
Starch in pressed juice can be removed by
adding amylases.
Fruit is also sold as itself e.g. tomatoes.
Transgenic Favr Savr tomatoes have been
engineered to not express a gene whose
protein causes the softening of fruit.
Protein name: polygalacturonase (degrades pectin
within the fruit causing it to soften)
o The engineered process:
Engineered Tomato DNA
Original Tomato DNA
gene
gene
mRNA
Polygalacturonase
Antisense
gene
mRNA
mRNAs are complementary to
each other and so combine
Protein expression
is prevented
Advantage of producing tomatoes this way
Tomatoes are able to ripen on the vine without
softening and bruising. This gives them a longer shelf
life.
This also increases the number of tomatoes that are
suitable to be sold, thus increasing profits/ reducing
costs lost to spoilage.
Past Paper Questions
2006 Q1
2006 Q3
2005 Q1
2003 Q1