Topic 3: Part F Flashcards
Some food, usually of plant origin contain..
naturally occurring toxins
Toxin
chemical substance that can cause damage to a biological system
Plants produce..
toxin chemicals as a form of natural defence against animals and microbes
No need to eliminate these foods from our diet because..
only small amounts are eaten in typical diet, therefore they don’t present a serious health hazard
Solanine
- narcotic like properties,
- lethal levels can be reached when potatoes are diseased, bruised, or exposed to sunlight.
- levels are controlled through breeding, handling, and storage.
- cooking doesn’t destroy this.
big list of natural carcinogens
apples bananas basil broccoli Brussel sprouts cabbage cantaloupe etc.
Natural toxin #2 - Cyanogens
- compounds that contain cyanide
- occurs during processing or inadequate storage, the compounds can be hydrolyzed to release free hydrocyanic acid (HCN) molecules
- HCN is a potent respiratory inhibitor
- found in lima beans, fruit sees such as apricot pits and tubers such as cassava
- long-term consumption can lead to ataxic neuropathy, a group of nervous disorders
Natural toxin #3 - Goitrogens
- compounds that inhibit proper utilization of iodine in the body
- causes the enlargement of the thyroid gland (goiter)
- found in cabbage and related species (broccoli, cauliflower)
Natural toxin #4 - Psoralen derivatives
- found in celery, parsnips, figs, and parsley
- also in oil of bergamot (a citrus oil once used in suntan lotions, now banned b/c associated with skin cancer)
Natural toxin #5 - Tannins
- found in tea, food rains, legumes, and wine
- located main in the seed coat of grains and legumes
- form insoluble complexes with proteins resulting in inactivation of digestive enzymes and protein insolubility
- may cause growth depression, decreased iron absorption, damage to mucosal lining of the gastrointestinal tract
- other effects include alteration in the excretion of certain nutrients such as minerals and increased excretion of proteins
Natural toxin #6 Phytate
- forms complexes with mineral ions and proteins, decreasing their bioavailability
- forms complexes with digestive enzymes, resulting in decreased digestion of food
- phytate is hydrolyzed during bread formation and during food fermentation
where is phytate found?
cereal grains, barley, legumes, some roots and tubers.
when does the highest rate of phyla hydrolysis occur?
during the dough proofing time, further hydrolysis occurs during baking and cooling
Natural toxin #7 - Oxalates
- binds calcium
- excessive levels of oxalic acid could lead to loss of calcium from bones
Where are oxalates found?
Spinach, rhubarb.
Negative symptoms of oxalate toxin
- may result in chronic disease such as kidney damage and formation of kidney stones
Natural toxin #8 - Saponins
- have similar properties to soaps. occur in a wide variety of legumes and cereals and ginseng
- particularly high content present in the seed coat of quinoa
- major effect is hemolysis of red blood cells
- may cause growth inhibition
Can Saponins be destroyed by cooking?
When can they be broken down?
- not destroyed by cooking, but can be hydrolyzed during fermentation
Hydrolyse
break down a compound by chemical reaction with water
Natural toxin #9 - Lectins
- lectins are proteins that possess a specific affinity for certain sugar molecules
- they cause agglutination of red blood cells
- orally ingested lectins are highly toxic to humans and animals
what does the binding of lectins reduce the ability of?
cells to absorb nutrients from the gastrointestinal tract
negative symptoms of lectins
- lead to serious growth retardation and in extreme cases, death
- can also cause cancer
how can lectins be destroyed?
- by heat used in traditional cooking
Natural toxin #10 - Enzyme inhibitors
- certain compounds in plants inhibit activity of trypsin, chymotrypsin, and amylase
- cause growth inhibition by interfering with protein digestion
