2.1 Flashcards
what are processed foods
products that have been preserved so they will not spoil as quickly as the fresh, whole foods they were made from
what’s the primary reason for processing foods
to reduce or eliminate harmful microbes from growing in foods
Also, to stop the loss of nutrients by deactivating the enzymes that break them down
negatives and positives about using heating to process foods
good: kills microbes
bad: kills some nutrients and quality
what is blanching
short heat treatment in processing of raw fruits and veggies to activate enzymes before other processing steps with minimal effect on microbes
what is pasteurisation
a mild form of heating that kills all pathogens without killing all the spoilage microbes
what is aseptic processing
sterilising the product before packaging (essentially extreme pasteurisation)
what is the most dangerous microbe that can survive in the absence of oxygen
clostridium botulinum
what are particulates and what is their purpose?
chunks floating in thick packaged sauces that makes it more difficult to predict heat-transfer patterns and therefore warm the bowl up entirely
how is heat energy transferred
conduction (from one molecule to another)
difference between heating and freezing when it comes to food preservation
heating kills microbes while freezing slows them down
what is the best way to freeze foods
rapidly with high power freezing winds, because putting it in the freezer gives a higher chance of nutrients being destroyed slowly
what is freezer burn
dehydration of frozen meats, which can be prevented by quick freezing and proper packaging
what does IQF stand for
individual quick freezing
used for fries and onion rings sometimes
what is the maximum temperature that defrosted foods can be stored at `
42° F
5° C
because microbes will start growing again
best methods of thawing frozen foods
microwave or leave in fridge overnight
why is drying an effective processing method
because microbes need water to grow
what is meant by the term concentrating in terms of food preservation
the removal of water from a liquid food without changing it into a solid
(e.g. juice concentrates and syrup)
why do some foods used concentration as a means of preservation
to condense liquids for production costs
also to kill microbes but mostly the first one
what is curing and what is it used for
adding preservatives to meat that bind water (sugar and salt) also sometimes sodium nitrate and sodium nitrite
also sometimes used for onions and potatoes except less salt and sugar is involved
what are some common methods for curing
soaking red meat in a salt solution called brine
hand rubbing the sugar into ham
what is milling
breaking down grains to make sure only the preservable stuff stays in
what is extracting
getting rid of stuff inside a food product that isn’t covered by any of the other methods of preservation
(spoiled parts of fruit juice, oils from plants
what is fermentation
it encourages the growth of beneficial microbes to outcomplete spoilage and pathogenic microbes
Normally lactic acid or ethanol is added to a product to begin this process
examples of foods that use fermentation
rising of bread dough (yeast)
alcohol (ethanol)
yogurt (lactic acid
and many more
what is irradiation
a potent killer of microbes that can be preserve foods with little to no heat
problems with irradiation
they kill microbes but do not inactivate toxins formed in the food before radiation
the use of gamma rays in the process has been scrutinised because they have had adverse affects to human health in the past
what is nonthermal processing and which foods use it
the killing of microbes under hydrostatic pressure, which keeps most health benefits
used with guac, hummus and salsa
most common methods of preservation that kill vitamins and minerals
freezing and heating
what are some points that defend the idea that processed foods are bad because they kill vitamins and minerals
raw materials and fresh foods are more likely to lose nutrients during storage than processed foods
cooking is very damaging to nutrients, and processed foods need much less cooking
define formulated foods
products that are mixtures of ingredients
what are some key differences between formulated foods and processed foods
formulated foods are not directly recognisable as their original plant or animal sources unlike processed foods
formulated foods have a much larger variety of ingredients
what is meant by the term clean label
a list of ingredients without anything that sounds like a chemical
normally comes with labels like ‘naked’ or ‘no artificial preservatives’
what are stabilisers
products added to food to prevent them from breaking down easily
what makes wheat flower superior from other flowers
the presence of gluten
most common ways to process foods
- sterilizing
- pasteurizing
- fermenting
- blanching
What are some examples of unit operations that convert raw materials into processed foods
- material handling
- cleaning
- pumping
- mixing
- heat exchanging
- packaging
what is wet milling
separates components on anatomical and solubility differences (protein, oil and starch)
what is dry milling
separates the seed into fractions based on anatomical structure (bran, germ, endosperm)
what is the difference between gamma and electron-beam radiation
gamma: from cobalt has great penetration capability but requires elaborate safety measures
electron-beam: has less penetration capability but fewer health risks
what is extrusion
A forming technique whereby a material is forced, by compression, through a shaped opening in a die to produce a continuous profile
what is leavening
refers to the production of gases (carbon dioxide) in dough that contribute to the volume achieved during baking and the final aerated texture
what are some examples of typical leavening agents
yeast, baking soda, baking powder, ammonium bicarbonate
common replacements for fat
Fake fat -Olestra (sucrose ester) Carbohydrate-based replacers -Gums and hydrocolloids Protein-based replacers -Milk or soy
