Principles Of Food Preservation Flashcards
3 principles of food preservation
Removal/inactivation of microorganism
Inactivate enzymes
Insect, worm/ rat removal
Micro filter materials
Asbestos pad
Porcalein
Diatomaceous earth
Enzymatic changes happening by phenolase, ppo
Phenols—>orthoquinones—->melanin
Phenolic comp—-quinones (ppo)
Who demonstrated heat preservation
Nicholas appert
Most heat resistant pathogen? Its heat treatment?
C. Botulinum
Moist heat 100°C 10min
Mild heat treatments
Pasteurization, blanching
Sterilization temp and canning temp
100/121° C wet heat- 15min
82-100°C 7-10min
or >74° C @centre
Blanching done prior to
Canning, freezing, dehydration
D,F &Z value
Time- minutes.90% / 10factor reduction of living cell
Time- specific no of living cell destroyed at constant temp 121°C
Temp increment- increase rate of destruction 10folds or
Reduce D vactor by factor of 10
Z value usually
8-12°C
Radiations tgat cause vreaking of chem bobd
X and free el ctrons
Recombined products and radicals during radiation
Hydrogen, hydrogen peroxide
H, OH and hydroperoxyl HO2 radicals
Life time of radicals
Countries that approved radiation
10^-5 sec
38
Radiolysis
Interaction and changes occuring by and on- IONISATION products on irradiated materilas
Radiation standard doses
*No toxicological/ nutritional/microbiological problem: max avg dose & is given by……condidered stand dose by….
* Max recommended dose
*Acg dose….by…..
10kGy….JECFA….Codex alumentarius
15
10
WHO
jECFA stands for
Joint FAO/IEAE/WHO Expert Committee on the Wholesomeness of Irradiated Food
Irradiation doses for
1 sterilization of herbs and spices
2” long term storage of meat
3 packaging material- cork
4 inactivation or control- parasite- pork
5destruction of pathogen- spices, frozen poultry, shrimp, meat
6 disinfect- flour, grain, cocoa, pods
7 inhibit sprouting
8mould control- soft fruits,
9 extent shelf life - soft fruits, fresh fish, meat at 0-4°C
7-10kGy
>= 50
10-25
0.1-6
2.5-10
0.1-2
0.1-0.2
2-5
2-5
Food usuitable for
1irradiation
2 freeze drying
1 dairy products and meat- rancidity
Vacuum packing
2 fatty food- melts and equipment inpairmnt
What accelerates unsuitableness of dairy prdts fir itradiation
Presence of oxygen
Order of sensutivity of water soluble vitamins
“ Fat soluble
TAP R FC B- B1, C, 2, 12, 9, 12, 7
EC AK D_ E CAROTENE,
Canning by….year….book…
Nicholas appert
1804
The art of preserving animal and veg substances for a many years
Low acid food….acid associated
> 4.6 ph
5% acetic acid
Browning preventing in blanching
SO2
Citric acid
Salt
……are mixed and effective to prevent loss of colour, texture, flavour
2000-4000ppm 2-5min
1-2%
Sugar, ascorbic acid, citric acid
…inhibits the enzyme….and refuce quinones in blanching
Ascorbic acid
Peroxidase
Dehydrated products are called…/…
High acid high sugar
High value low vol
Difference between- drying, dehydration, evaporation
Sun
Controlled condtn
Liquid—liquid, surface loss
Drying ratio/ dehydration ratio
Viscous/ paste / aticky materials dried tgrough
Water content/ dry matter
Drum dryers
Mechanism or graph of drying/ dehydration
AB-BC-CD
Initial to wet bulb temp
Constant rate perood, wet,max water activity =1, till critical mc
Falling rate period- dry, water act<1, till eq mc
Mechanism or graph of drying/ dehydration
AB-BC-CD
Initial to wet bulb temp
Constant rate perood, wet,max water activity =1, till critical mc
Falling rate period- dry, water act<1, till eq mc