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Flavonoids are classified as a type of carbohydrates.
Flavonoids are classified as a type of carbohydrates.
False
The average diet in the Western world may include more than 1 g of flavonoids daily.
The average diet in the Western world may include more than 1 g of flavonoids daily.
True
Condensed tannins are identical to hydrolyzable tannins.
Condensed tannins are identical to hydrolyzable tannins.
False
Tannic acid is known to cause acute liver injury.
Tannic acid is known to cause acute liver injury.
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Quercetin is considered safe and non-carcinogenic in mammals.
Quercetin is considered safe and non-carcinogenic in mammals.
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Tea has the highest tannin content among beverages.
Tea has the highest tannin content among beverages.
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Coumarin is a type of mineral found in natural flavorings.
Coumarin is a type of mineral found in natural flavorings.
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The phenolic substances identified include safrole and myristicin.
The phenolic substances identified include safrole and myristicin.
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Milk can be contaminated with tremetone when animals ingest certain toxins.
Milk can be contaminated with tremetone when animals ingest certain toxins.
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The mortality rate from milk sickness ranges from 5% to 10%.
The mortality rate from milk sickness ranges from 5% to 10%.
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Algal blooms do not contribute to seafood poisoning.
Algal blooms do not contribute to seafood poisoning.
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Paralytic shellfish poisoning (PSP) is caused by eating shellfish contaminated with saxitoxin.
Paralytic shellfish poisoning (PSP) is caused by eating shellfish contaminated with saxitoxin.
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Symptoms of paralytic shellfish poisoning develop more than two hours after ingestion.
Symptoms of paralytic shellfish poisoning develop more than two hours after ingestion.
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Diarrhetic shellfish poisoning (DSP) can be caused by eating mussels contaminated with okadaic acid.
Diarrhetic shellfish poisoning (DSP) can be caused by eating mussels contaminated with okadaic acid.
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Symptoms of DSP can include nausea and abdominal pain.
Symptoms of DSP can include nausea and abdominal pain.
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Natural toxins are chemicals that can have potentially toxic effects on humans due to their natural occurrence in food.
Natural toxins are chemicals that can have potentially toxic effects on humans due to their natural occurrence in food.
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Red tide occurs due to a bloom of toxic diatoms.
Red tide occurs due to a bloom of toxic diatoms.
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Tetrodotoxin, a neurotoxin found in puffer fish, is commonly transmitted to the edible parts of the fish even with expert cleaning.
Tetrodotoxin, a neurotoxin found in puffer fish, is commonly transmitted to the edible parts of the fish even with expert cleaning.
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Chronic ingestion of natural toxins is often required to induce adverse effects.
Chronic ingestion of natural toxins is often required to induce adverse effects.
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Toxic phenolic substances are classified into groups based on their taste, color, and frequency of occurrence.
Toxic phenolic substances are classified into groups based on their taste, color, and frequency of occurrence.
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There are over 800 identified phenolic substances in plants, most of which are highly toxic.
There are over 800 identified phenolic substances in plants, most of which are highly toxic.
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Coumarin, safrole, and gossypol are examples of less toxic phenolic substances.
Coumarin, safrole, and gossypol are examples of less toxic phenolic substances.
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Endogenous toxins of plant origin can be classified based on common functional groups and physiological action.
Endogenous toxins of plant origin can be classified based on common functional groups and physiological action.
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Biogenic amines and central stimulants are forms of natural toxins that induce harmful effects immediately upon ingestion.
Biogenic amines and central stimulants are forms of natural toxins that induce harmful effects immediately upon ingestion.
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Cyanogenic glycosides can produce lethal doses of cyanide in humans.
Cyanogenic glycosides can produce lethal doses of cyanide in humans.
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Safrole is banned for food use in both the European Community and the US due to health risks.
Safrole is banned for food use in both the European Community and the US due to health risks.
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Myristicin is primarily found in nutmeg and has been linked to potential toxicity.
Myristicin is primarily found in nutmeg and has been linked to potential toxicity.
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American varieties of lima beans produce more cyanide than Asiatic varieties.
American varieties of lima beans produce more cyanide than Asiatic varieties.
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Cyanogenic glycosides consist of a saccharide moiety and an aglycone.
Cyanogenic glycosides consist of a saccharide moiety and an aglycone.
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The degradation of linamarin does not produce any harmful substances.
The degradation of linamarin does not produce any harmful substances.
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Glycosidases and hydroxynitrile lyase enzymes are found in plant cells and become active when plant tissue is damaged.
Glycosidases and hydroxynitrile lyase enzymes are found in plant cells and become active when plant tissue is damaged.
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Coumarin is harmful and does not occur in safe flavorings like lavender.
Coumarin is harmful and does not occur in safe flavorings like lavender.
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Caffeine is more potent than theophylline and theobromine.
Caffeine is more potent than theophylline and theobromine.
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Pyrrolizidine alkaloids can cause acute liver damage.
Pyrrolizidine alkaloids can cause acute liver damage.
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The primary source of caffeine in our diet is tea.
The primary source of caffeine in our diet is tea.
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Contamination from mixing edible plants with toxic plants is a major source of natural contaminants.
Contamination from mixing edible plants with toxic plants is a major source of natural contaminants.
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Pyrrolizidine intoxication has been reported in Australia.
Pyrrolizidine intoxication has been reported in Australia.
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Consumption of meat contaminated with toxic substances from plants is very common.
Consumption of meat contaminated with toxic substances from plants is very common.
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Caffeine is found in cocoa beans but not in cola nuts.
Caffeine is found in cocoa beans but not in cola nuts.
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The consumption of contaminated millet is linked to pyrrolizidine alkaloids.
The consumption of contaminated millet is linked to pyrrolizidine alkaloids.
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Cassava is low in starch and is not an important food source in Africa.
Cassava is low in starch and is not an important food source in Africa.
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The process of preparing cassava involves grating, soaking, and fermenting to reduce cyanogen content.
The process of preparing cassava involves grating, soaking, and fermenting to reduce cyanogen content.
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Consumption of dry, unfermented cassava is safe and does not affect health.
Consumption of dry, unfermented cassava is safe and does not affect health.
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Glucosinolates are actively toxic rather than their hydrolysis products.
Glucosinolates are actively toxic rather than their hydrolysis products.
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Isothiocyanates have been identified as non-toxic in embryonic studies involving rats.
Isothiocyanates have been identified as non-toxic in embryonic studies involving rats.
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Acetylcholinesterase inhibitors are primarily found in members of the Solanaceae family, such as potatoes.
Acetylcholinesterase inhibitors are primarily found in members of the Solanaceae family, such as potatoes.
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Nitriles formed from glucosinolates are considered safe and have no known risks.
Nitriles formed from glucosinolates are considered safe and have no known risks.
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Thiocyanate is a metabolite formed from cyanide in the presence of rhodanase.
Thiocyanate is a metabolite formed from cyanide in the presence of rhodanase.
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Study Notes
Natural Toxins
- Natural toxins are chemicals found in food that can be harmful to humans.
- Typically, these toxins aren't acutely toxic but can cause problems with chronic ingestion or allergic reactions.
- Some natural toxins are more dangerous to animals and some are acutely toxic to animals too.
- The expert cleaning of puffer fish prevents transmission of tetrodotoxin to the edible parts (tetradotoxin is a neurotoxin). However accidents still occur each year.
Natural Toxins Include
- Endogenous toxins of plant origin
- Contaminants of natural origin
- Toxins of microbial origin
Endogenous Toxins of Plant Origin
- No single method for classifying the toxic components of plants
- Classified by functional groups: toxic phenolic substances, cyanogenic glycosides, glucosinolates
- Classified by physiological action: acetylcholinesterase inhibitors
- Classified by type of effect: biogenic amines and central stimulants
Toxic Phenolic Substances
- More than 800 phenolic substances have been found in plants.
- Many contribute to taste, flavor, and color of foods.
- Divided into two groups based on frequency of occurrence, structural relationship, and relative toxicity
Widespread Phenolic Substances
- Widely used in food and beverages (e.g., caffeic acid, ferulic acid, gallic acid, flavonoids)
- Usually, not acutely toxic at the levels they're found in food.
More Heterogeneous Group of Highly Toxic Phenolic Substances
- Coumarin, safrole, myristicin, phenolic amines (catecholamines), and gossypol.
- These are highly toxic.
Flavonoids
- A class of plant pigments found in human food.
- Present as ẞ-glucosides
- Include derivatives like aglycones , glycosides , and methyl ethers
- Classified into six subgroups.
Flavones
- Group of yellow pigments occurring abundantly in foods (e.g., nobiletin, tangeretin)
- Investigated for mutagenicity.
- Quercetin the only flavonoid shown to be carcinogenic after oral administration.
Tannins
- Heterogeneous group of broadly distributed plant substances.
- Includes all polyhydric phenols with molecular weights exceeding 500.
- Two types: hydrolyzable (gallic, digallic, and ellagic acid esters of glucose) and condensed (polymers of leukoanthocyanidins)
- Found in numerous foods (e.g., tropical fruits, tea, coffee, cocoa).
- High concentration found in black tea – up to 450 mg/cup.
Coumarin, Safrole, and Myristicin
- Examples of natural toxins found in various flavorings such as cassis, lavender, and lovage
- Coumarin can be found in citrus oils and some edible fruits.
- Safrole can cause liver tumors in rats and is prohibited in the US
- Myristicin may contribute to the toxicity of nutmeg and can cause tachycardia, failing salivation, central nervous system excitation.
Cyanogenic Glycosides
- Glycosides from which cyanide is formed.
- Widely spread in plants such as lima beans and cassava
- Lethal doses can be reached after consuming cyanogenic foods.
- Quantities vary between Asiatic and American varieties of lima beans
- Lower-cyanide varieties of lima beans are being bred. Beta-hydroxynitrile
Glycosidases and Hydroxynitrile Lyase
- Present in plant cells, becoming available when the tissue is damaged.
- Removal of cyanogenic glycosides for safer food preparation. Example, "gari," a fermented cassava preparation.
High Consumption of Dry Cassava
- High cyanogen levels in unfermented cassava can lead to goiter.
- Cyanide can be metabolized into thiocyanate.
Glucosinolates
- Group of substances in cruciferous plants(e.g., cabbage, turnips) that can be antinutritive.
- Their hydrolysis products (isothiocyanates, thiocyanate, and nitriles) are the toxic agents.
- Isothiocyanates can be embryotoxic to rats.
- Nitriles are precursors to nitroso compounds.
Acetylcholinesterase Inhibitors
- Alkaloids found in various edible fruits and vegetables.
- Includes broccoli, Valencia oranges, sugar beet, cabbage, pepper, carrot, strawberry, apple, lima bean, and radish.
- Found in potato, eggplant, and tomato
Solanine
- The most potent acetylcholinesterase inhibitor in potatoes.
- Found primarily in the skin of potatoes.
- Heat-stable and insoluble; cooking doesn't remove solanine.
- 20mg / 100g fresh weight considered unsafe.
Chaconine and Tomatine
- Glycoalkaloids found in potatoes, with biological properties similar to solanine.
- Symptoms of potato poisoning are likely due to combined actions of the alkaloids.
Biogenic Amines
- Certain amines found in plants and microorganisms.
- Important examples in plants include dopamine, epinephrine, norepinephrine, serotonin, and tyramine.
Dietary Intake of Biogenic Amines
- Could pose risks; especially when combined with MAO inhibitors.
- MAO (monoamine oxidase) inhibitors block oxidative deamination.
Central Stimulants
- Include methylxanthines (caffeine, theophylline, theobromine).
- Found in coffee, tea, cocoa beans, and cola nuts.
Caffeine and Methylxanthines
- Caffeine stimulates the peripheral and central nervous systems.
- Caffeine is more potent than theophylline and theobromine.
Natural Contaminants
- Contamination from mixing edible plants with toxic nonnutritive plants (e.g., pyrrolizidine alkaloids).
- Contamination resulting from animal intake of toxic substances (e.g., milk sickness caused by tremetone).
- Contamination of seafood with phycotoxins (e.g., Paralytic Shellfish Poisoning (PSP), Diarrhetic Shellfish Poisoning (DSP)).
Red Tide
- Dinoflagellate bloom causes discoloration of the sea.
- High toxicity of shellfish during red tide.
- Strict regulations and awareness are important to prevent seafood contamination.
Effect of Thermal Processing on Phycotoxins
- Cooking moderately reduces phycotoxin concentrations in mollusks.
Toxins of Microbial Origin
- Microorganisms are ubiquitous.
- Their absence indicates unusual or special conditions in an environment.
- Foodborne diseases are either infections or intoxications.
- Toxins can be produced by bacteria, fungi, algae, and the toxic metabolites such as biogenic amines and ethyl carbamate
Bacterial Toxins
- Classified based on how they work on the human body.
- Sub-unit toxins (e.g., Clostridium botulinum toxins)
- Membrane-affecting toxins (e.g., Staphylococcus aureus toxins)
- Lesion-causing toxins (e.g., Clostridium perfringens and Bacillus cereus toxins)
- Immuno-active endotoxins (e.g., Gram-negative bacteria toxins)
Mycotoxins
- Secondary metabolites of fungi.
- Cause acute and chronic toxins in animals/humans.
- Aspergillus, Penicillium, and Fusarium (examples of fungi that produce mycotoxins)
- Environmental conditions affect mycotoxin production.
Toxic Microbial Metabolites
- Biogenic amines (e.g., dopamine, epinephrine, norepinephrine, serotonin, and tyramine) which are produced by Enterobacteriacea and Enterococci
- Ethyl carbamate (urethane)
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Description
Test your knowledge of food toxicology and the effects of flavonoids in this quiz. Key topics include tannins, shellfish poisoning, and the safety of various food substances. Dive into the science behind these compounds and their implications for health and nutrition.
