Transcript Types of Food Preservatives

Types of Food Preservatives
Maintaining freshness
Preservatives – substances add to food to prevent
or slow spoilage and maintain natural colors and flavors
• 2 reasons for food spoilage
– Microbial contamination
– Fats reacting with oxygen (Oxidation)
• Preservative criteria:
– Nontoxic
– Functional
– Flavorless
– economical
Antimicrobial agents – prevent the growth of
microbes in food
• Salts and sugars
– Oldest and most used types
– Dehydrate food (microbes can’t grow without water
• Nitrates (NO3)
– NaNO3 most common
– Controls the bacteria that cause botulism
– React with amino acids to form nitrosamines (carcinogen)
• Illegal according to Delaney act but risk of botulism to high
• Legislation allows use until safe alternative found
Antimicrobial agents cont.
• Acids
– Acetic, ascorbic, citric, lactic, benzoic, and propionic
– Prevent microbe growth by lowering pH of food
– Calcium propionate (C6H12CaO5) prevents mold in bread
– Sorbic (C6H8O2)and benzoic acid (C6H6O2) work together
• Control mold, yeast, and bacteria in soft drinks
Antioxidants
• Protect foods from changes caused by exposure to oxygen
• Interfere with the formation of free radicals
– Atoms or groups of atoms with 1 or more unpaired electrons
• They are unstable and highly reactive
• Cause fats to become rancid ad trigger enzymatic browning
• Can cause the formation of carcinogens
• Antioxidants donate hydrogen atoms to free radicals
– Create a stable compound
see pages 467-468 for more info on Antioxidants
Sulfites
• Controversial group of antioxidants
• Salts that contain sulfur
– Sulfur dioxide, sodium sulfite, sodium and potassium bisulfite
• Added to frozen and dried produce to prevent browning
• Use on fresh produce banned by FDA 1986
– Dangerous allergic reactions
• Can’t be used on foods that are a source of thiamin
– Sulfites destroy thiamin