Lecture - Natural Food Toxicants

Lecture - Natural Food Toxicants - Natural Toxicants in...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Natural Toxicants in Food Complexity of Food Nutrients • Carbohydrates •P r o t e i n s • Lipids • Minerals • Vitamins Non-nutrients • Food Additives • Naturally Occurring • Contaminants • Processing Chemicals Nonnutrient Chemicals in Different Foods • Cheddar Cheese 160 • Orange juice 250 • Banana 325 • Tomato
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Natural Toxicants • Goitrogens • Cyanogenic glycosides • Lathyrism • Lectins • Alkaloids • Protease inhibitors • Vasoactive amines Natural Toxicants in Food Goitrogens • Contribute to growth of goiters • Compounds in Cruciferae veggies Brassica species (cabbage,kale,turnips) – Seeds only - not leaves • Combined w/ iodine deficiency
Background image of page 2
Natural Toxicants in Food Goitrogens • Goitrogenic compounds (goitrin) formed from breakdown of glucosinolates by thioglucosidase • Goitrogenic metabolites – nitriles – thiocyanates – oxazolidine Natural Toxicants in Food Goitrogens • Thyroid gland secretes thyroxine (TY), triiodothyronine (TII), thyroglobulin(TH) • Controlled by hypothalamus and pituitary • Hypothalamus produces thyrotropin- releasing hormone (TRH) • Stimulates pituitary to release thyroid- stimulating hormone (TSH) Natural Toxicants in Food Goitrogens • TSH promotes uptake of iodine, synthesis of TH and release of TY and TII which feed back to reduce TSH • TY and TII hormones affect – oxygen consumption, cardiovascular function, neuromuscular activity, cholesterol metabolism, cerebral function – growth and development
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Natural Toxicants in Food Goitrogens • Goitrin and thiourea inhibit TY synthesis • Thiocyanates, oxazolidine and nitriles inhibit uptake of iodine by thyroid • Lack of iodine causes thyroid to enlarge and hypervascularate to trap more iodine = goiter Natural Toxicants in Food Goitrogens-Testing • Weight and histology of thyroid • Growth rate of animal • Iodine content of blood and thyroid • Feed compound - measure uptake of radioactive iodine
Background image of page 4
Natural Toxicants in Food Cyanogenic Glycosides • Plant • Bitter almond • Cassava root • Sorghum • Lima bean • Glycoside • Amygdalin • Linamarin • Dhurrin • Linamarin Natural Toxicants in Food Cyanogenic Glycosides • Toxic chemical = hydrogen cyanide • HCN released when plant is chewed or chopped • Releases 2 enzymes normally separate – beta-glucuronidase –hydroxyn itr
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 22

Lecture - Natural Food Toxicants - Natural Toxicants in...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online