Food
Preservation
Chapter 13
Heat Treatments
1,Blanching – Heat to deactivate
enzymes
2,Pasteurization – Heat to kill
pathogenic bacteria
3,Sterilization – Heat to kill all
bacteria and other organisms
Low Temperature
1,Refrigeration - < 40° F
2,Freezing - 0° F
Lowering Water Activity
1,Dehydration
2,Concentration
3,Salt
4,Addition of Sugar
Chemical Preservation
Food Additives
Food additives are any
substitute that becomes
part of a food product
either directly or indirectly
during processing,storing
or packaging.
Regulations on Food
Additives
1,The Food and Drug Administration
2,1938 Food Drug and Cosmetic Act
3,1958 and 1960 Amendments
1,Delaney Clause
GRAS
? Generally Recognized As Safe
? First established 700 placed on the
list without going through testing
? Now those substances are being
reevaluated
? Foods have been removed
What It Takes to Become A
Food Additive
1,Prove additive is effective
2,Prove additive can be detected and
measured in final products
3,Study the effects of the substance on
animals (in large doses)
4,Submit results to validate the findings
5,Schedule a public hearing
6,FDA approves or rejects
Functions of Food Additives
1,Preservatives – Keep food fresh and
reduce spoilage,Control bacteria,mold,
fungi,and yeast,
Benzoates
BHT,BHA (antioxidants)
Calcium Propionate (inhibits molds)
Sodium Bisulfate
Sodium Nitrate
Functions of Food Additives
2,Processing Aids – Improve
consistency,add stability,aid oil and
water mixtures,and retain moisture
Gums (Algin,Carrageenan,Xanthan)
Aluminum Calcium Silicate
Benzoyol Peroxide
Functions of Food Additives
3,Nutrients – Maintain or improve the
nutritional quality of food,
Alpha- tocopherol
Ascorbic Acid
Biotin
Beta Carotene
Calcium Pantothenate
Folic Acid
Functions of Food Additives
4,Flavors – Complement,magnify or
modify the taste of aroma of a food
Aspartame
Corn Syrup
Ethyl Vanillin
Mannitol
Monosodium Glutamate
Functions of Food Additives
5,Colors –Give foods a desired,
appetizing or characteristic color,
Carmel
Beta-apo-8-Carotenal (Orange)
Citrus Red
FD&C Blue No 1
FD&C Red No 3
FD&C Yellow No 5
Other Methods of
Preservation
Controlled or Modified
Atmosphere Storage and
Packaging
1,Modified Atmosphere (MA)
1,Nitrogen
2,CO2
2,Controlled Atmosphere (CA)
1,Vacuum Packaging
2,Shrink Wrapping
Irradiation
1,Pasteurization
2,Sterilization
Irradiation
? kGy
? Food approved in the US
? Pork
? Chicken
? Beef
? Fruits and Vegetables
? Grain
? Many other foods approved in other
countries
Irradiation Source
-
Irradiated Beef Patties
Purpose
To evaluate ordor,flavor,
texture,and overall
acceptability of irradiated
ground beef patties stored
over a six-week period
300-2.8 oz patties were blast frozen
Packed 20 patties per Cryovac bag
Vacuum sealed
Placed in a corrugated box and
packed in dry ice
Irradiated in Florida
Dosimeter placed inside boxes
Stored at –18° C
Sampled weekly for 6 weeks
Overall acceptability
of irradiated ground beef patties
0 1 3 5 7 Dose (kGy)
Weeks
0 6.3 5.9 6.5 6.8 6.0
1 6.6 6.7 6.3 6.2 6.2
2 6.0 6.3 6.0 6.3 6.6
3 6.4 6.3 6.2 6.1 6.2
4 6.6 6.3 5.7 6.2 5.8
5 6.4 5.9 5.5 5.9 5.3
6 5.7 6.2 5.4 6.0 5.1 1 (=dislike
9 (=like)
Irradiated
Strawberries
Materials and Methods
?Fruit were irradiated at doses of
0,0.25,0.5,0.75 and 1
?Stored for periods of 0,1,3,5,and 7
days at 2oC
Results
Ascorbic Acid
Ascorbi c Acid
Day
0 2 4 6
?
m
/ g fre
s
h w
e
ight
24
26
28
30
32
34
36
38
0 k Gy
1 kG y
Results
DHA
Dehy droascorbic acid
Day
0 2 4 6
?
m
/g
fresh w
eight
0
2
4
6
8
10
12
14
0 kGy
1kGy
Irradiated
Strawberries