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Questions and Answers
Chelating agents can form stable complexes with metal ions.
Chelating agents can form stable complexes with metal ions.
True
Prooxidants only promote the formation of lipid hydroperoxides.
Prooxidants only promote the formation of lipid hydroperoxides.
False
The presence of chelating agents in food can lead to precipitation and discoloration.
The presence of chelating agents in food can lead to precipitation and discoloration.
False
Ionizing radiation is considered a prooxidant in food systems.
Ionizing radiation is considered a prooxidant in food systems.
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Chelating agents contribute negatively to the stability of food color, aroma, and texture.
Chelating agents contribute negatively to the stability of food color, aroma, and texture.
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Singlet oxygen is a type of prooxidant that enhances food preservation.
Singlet oxygen is a type of prooxidant that enhances food preservation.
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Lipid hydroperoxides are formed exclusively by prooxidants.
Lipid hydroperoxides are formed exclusively by prooxidants.
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The action of polyphenol oxidase in foods can lead to undesirable oxidation reactions.
The action of polyphenol oxidase in foods can lead to undesirable oxidation reactions.
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Phytoalexins are primarily effective against bacteria rather than fungi.
Phytoalexins are primarily effective against bacteria rather than fungi.
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Isoflavonoids have a C6-C3-C6 basic skeleton structure.
Isoflavonoids have a C6-C3-C6 basic skeleton structure.
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Gram-negative bacteria are more sensitive to essential oils than Gram-positive bacteria.
Gram-negative bacteria are more sensitive to essential oils than Gram-positive bacteria.
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Capsidiol is an antimicrobial compound found in pepper.
Capsidiol is an antimicrobial compound found in pepper.
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Terpenes/terpenoids in essential oils can disrupt the bacterial cell membrane.
Terpenes/terpenoids in essential oils can disrupt the bacterial cell membrane.
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Ascorbic acid can reduce reactive oxygen species such as hydrogen peroxide.
Ascorbic acid can reduce reactive oxygen species such as hydrogen peroxide.
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SO2 is less effective against Gram-negative bacteria than Gram-positive bacteria.
SO2 is less effective against Gram-negative bacteria than Gram-positive bacteria.
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Sulfites are primarily used for inhibiting enzymatic browning in fruits and vegetables.
Sulfites are primarily used for inhibiting enzymatic browning in fruits and vegetables.
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Sulfurous acid is the least effective form of sulfites in food preservation.
Sulfurous acid is the least effective form of sulfites in food preservation.
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SO2 acts as an antioxidant by directly eliminating oxygen from foods.
SO2 acts as an antioxidant by directly eliminating oxygen from foods.
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Sulfite filters are commonly used in the winemaking process.
Sulfite filters are commonly used in the winemaking process.
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The main goal of using SO2 during the prefermentation process is to promote oxidation.
The main goal of using SO2 during the prefermentation process is to promote oxidation.
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High pH levels enhance the effectiveness of sulfites against yeast.
High pH levels enhance the effectiveness of sulfites against yeast.
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Excessive usage of EDTA in foods could lead to depletion of calcium and other cationic minerals in the body.
Excessive usage of EDTA in foods could lead to depletion of calcium and other cationic minerals in the body.
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Pink discoloration in canned pears is caused by a purple-pink insoluble tin-anthocyanin complex.
Pink discoloration in canned pears is caused by a purple-pink insoluble tin-anthocyanin complex.
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Blue discoloration in crab meat does not involve the presence of biuret.
Blue discoloration in crab meat does not involve the presence of biuret.
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Chill Haze in beer occurs when the beer is chilled below approximately 1.6°C.
Chill Haze in beer occurs when the beer is chilled below approximately 1.6°C.
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Polyphosphates and EDTA are utilized in canned seafood to enhance the formation of glassy crystals.
Polyphosphates and EDTA are utilized in canned seafood to enhance the formation of glassy crystals.
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Chelating agents can stabilize fermented malt beverages by complexing copper.
Chelating agents can stabilize fermented malt beverages by complexing copper.
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Tartaric acid and its salts are added to cheese to enhance color and increase rancidity.
Tartaric acid and its salts are added to cheese to enhance color and increase rancidity.
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Seafood contains substantial amounts of magnesium that can react with ammonium phosphate to produce crystals.
Seafood contains substantial amounts of magnesium that can react with ammonium phosphate to produce crystals.
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Chelating agents are effective antioxidants.
Chelating agents are effective antioxidants.
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Raising the pH enhances the efficiency of chelating agents.
Raising the pH enhances the efficiency of chelating agents.
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Citric acid can solubilize fats and oils.
Citric acid can solubilize fats and oils.
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EDTA salts are ineffective in emulsion systems.
EDTA salts are ineffective in emulsion systems.
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Trace elements can catalyze oxidation in fats and oils.
Trace elements can catalyze oxidation in fats and oils.
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Ascorbic acid is unaffected by copper and iron.
Ascorbic acid is unaffected by copper and iron.
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The term 'chelate' comes from the Latin word for crab claw.
The term 'chelate' comes from the Latin word for crab claw.
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Pink discoloration in canned pears is caused by trace minerals.
Pink discoloration in canned pears is caused by trace minerals.
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High doses of SO2 can cause organoleptic changes of the final product and some allergies.
High doses of SO2 can cause organoleptic changes of the final product and some allergies.
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Propyl gallate (PG) is a natural antioxidant derived from gallate acid.
Propyl gallate (PG) is a natural antioxidant derived from gallate acid.
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Gallates exhibit higher antioxidant activity in fats with maximum moisture.
Gallates exhibit higher antioxidant activity in fats with maximum moisture.
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Propyl gallate is considered unstable and not suitable for frying fats.
Propyl gallate is considered unstable and not suitable for frying fats.
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BHA is effective in protecting lipids containing fatty acids with shorter chains, such as in coconut oil.
BHA is effective in protecting lipids containing fatty acids with shorter chains, such as in coconut oil.
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Butylated hydroxyanisole (BHA) is less effective than propyl gallate in stabilizing free radicals.
Butylated hydroxyanisole (BHA) is less effective than propyl gallate in stabilizing free radicals.
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BHT can stop autooxidation by converting hydroperoxides into stable radicals.
BHT can stop autooxidation by converting hydroperoxides into stable radicals.
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BHA and BHT are often blended with other synthetic antioxidants to improve their antioxidative properties.
BHA and BHT are often blended with other synthetic antioxidants to improve their antioxidative properties.
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Study Notes
Additives
- Acids
- Bases
- Buffer systems and salts
- Chelating agents
- Antioxidants
- Emulsifiers
- Gums
- Flavor Substances
- Flavor enhancers
- Stabilizers & Thickeners
- Anticaking agents
- Gases
- Firming Texturizers
- Clarifying Agents
- Flour Bleaching Agents
- Colorants
- Fat replacers
- Antimicrobial agents
- Sweeteners
Redox Reactions in Food
- Redox Reactions involve the gain or loss of electrons.
- Oxidation is the loss of electrons, increasing the oxidation number.
- Reduction is the gain of electrons, decreasing the oxidation number.
- Redox reactions are important in food because they can lead to undesirable changes like enzymatic browning.
Enzymatic Browning
- Hydroxylation and oxidation reactions catalysed by polyphenol oxidase.
- Reactions lead to a change in color.
- Oxidation reactions are caused by polyphenol oxidase.
Prooxidants
- Promote the formation of lipid hydroperoxides.
- Promote the formation of free radicals (singlet oxygen, ionizing radiation, lipoxygenase).
- Promote decomposition of hydroperoxides (transition metals, light, elevated temperatures).
Lipid Oxidation
- Initiation, propagation, and termination are the three stages.
- Primary oxidation products are lipid hydroperoxides.
- Secondary oxidation products include volatile aldehydes, ketones, alcohols, acids, hydrocarbons, and non-volatile aldehydes.
Chelating Agents (Sequestrants)
- Prevent the formation of colored or insoluble compounds of free metal ions.
- Prevent the degradation of food components.
- Improve the stabilization of food color, aroma, and texture.
- Useful for stabilizing food colors, aromas and textures.
Phytic Acid
- Known as inositol hexakisphosphate (IP6).
- Principal storage form of phosphorus in many plant tissues.
- Found in cereals, grains, bran, and seeds
- Can bind to important minerals (calcium, iron, and zinc).
- Can inhibit metal-induced discolorations, and remove calcium from pectic substances in cell walls.
Antioxidants
- Prevent or delay oxidative deterioration in foods.
- Prevent undesirable changes (bad odor, loss of taste, rancidity).
- ROS (reactive oxygen species) are stabilized or removed
Action Mechanisms of Antioxidants
- Quenching: Scavenge singlet oxygen (O2)
- Charge transfer: Donate electrons to reactive species
- Bond breaking: React with lipid radicals to terminate oxidation chain reactions.
Natural Antioxidants: Tocopherol (Vitamin E)
- Collective name for eight related tocopherols and tocotrienols
- Fat-soluble vitamins with antioxidant properties.
- Primarily a-tocopherol.
- Found in vegetable oils.
- Effective as a membrane protector against oxidation caused by lipid radicals.
Natural Antioxidants: Ascorbic Acid (Vitamin C)
- A monosaccharide.
- Antioxidant found in animal and plant tissues.
- Necessary for humans as it cannot be synthesized.
- Acts as a reducing agent (scavenging oxygen) in foods.
Natural Antioxidants: Sulfites and Sulfur Dioxide
- Used as microbial growth and enzymatic/non-enzymatic browning inhibitors, as well as antioxidants and reducing agents in food preservation.
- High effectiveness and efficiency in acid medium
- More effective against Gram-negative bacteria
Synthetic Antioxidants
-
BHA (Butylated Hydroxyanisole):
-
Contains di-tert-butyl groups, effective as primary antioxidants.
-
Effective in fats, oils, and oil-in-water emulsions.
-
Synergistic when combined with other antioxidants.
-
BHT (Butylated Hydroxytoluene):
-
Effective against lipid radicals.
-
White crystalline solid.
Synthetic Antioxidants: Sodium Erythorbate
- Sodium salt of erythorbic acid.
- Primarily used in meats, poultry, and soft drinks.
- Structurally related to vitamin C, improves flavor stability.
Antimicrobial Agents
- Substances which control microbial growth.
Antimicrobials: Mechanism of Action
- Affect genetic systems (replication and transcription, DNA/RNA, protein synthesis inhibition).
- Impact on the cell wall/membrane (affecting cell wall synthesis, permeability).
- Inhibit enzymes.
- Bind to essential nutrients.
Antimicrobials: Epoxides
- Useful for sterilizing low-moisture foods and packaging materials.
- Include ethylene oxides and propylene oxides.
Antimicrobials: Nitrate and Nitrites
- Used in curing meats for color development and inhibition of Clostridium botulinum.
- Form nitric oxide that react to myoglobin, which forms pigments.
Antimicrobials: Bacteriocins
- Produced by certain lactic acid bacteria.
- Effective against Gram-positive bacteria.
- Used in foods.
Antimicrobials: Phytoalexins
- Produced by healthy plant cells in response to infection.
- Antimicrobial activity primarily against fungi.
Antimicrobials: Essential Oils
- Have antimicrobial activity, often disrupting cells, leading to their death.
- Used to preserve a variety of food products.
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Description
This quiz explores key concepts related to food additives, redox reactions, and enzymatic browning. Understand the role of different agents and the chemical processes that affect food quality. Test your knowledge on how these concepts influence food preservation and flavor enhancement.
