Antinutritional Components in Food PDF

Food product development Antinutrtional components in food PROF. DR HAB. JOANNA KOBUS-CISOWSKA Food Intake Health Risks Microbiological Risks Toxicological Risks Infection Intoxication  Food Food is fundamental importance...

Food product development Antinutrtional components in food PROF. DR HAB. JOANNA KOBUS-CISOWSKA Food Intake Health Risks Microbiological Risks Toxicological Risks Infection Intoxication  Food Food is fundamental importance to life Food Human consumes 30 tons of food during his lifetime Mixture of chemicals Nutrients (99,9%) Toxin Contaminants Additives Risk???  Natural Toxins They are naturally present in plants & animals. The long term ingestion of natural toxins in commonly eaten foods à the risks to human health? Most of the natural toxins, particularly those occurring in plant-derived foods, induce allergic reactions.  Risks of toxins in food General toxicity (instant death or illness) Carcinogenic Mutagenic Teratogenic Hormones Microbial pathogens  Natural Toxins in Foods Endogenous toxins of plant origin § Cyanogenic glycosides § Glucosinolates § Acetylcholinesterase inhibitors § Biogenic amines § Central stimulants Natural contaminants § Mixing of edible plants with toxic plants § Contamination resulting from intake of toxic substances by animals § Microbial toxins Endogenous toxins of plant origin  Antinutritient coumponds Plants, fungi, and bacteria synthesize a range of low and high molecular weight compounds. These secondary metabolites play a role in defense against herbivores, insects, pathogens, or adverse growing conditions. Many of these compounds may be labeled as antinutrients in the human diet due to their occurrence in fresh foods and processed foodstuffs. The major antinutrients mostly found in plant: Protein sources:toxic oxalates, amino acids, saponins, goitrogens, lectins Cyanogenic glycosides, (phytohaemagglutinins), tannins, Protease inhibitors, phytic acid, fatty derivatives gossypol, amylase inhibitors. Flavonoids – exceptions ??? In very high amounts (for example, 140 grams per day), flavonoids act as antinutritional components  Source of tannins Fruits, tea (highest content), coffee, cocoa, grape, wine A cup of ground coffee: 72-104 mg instant coffee: 11-128 mg 1 g of tannins per day Toxicity of some tannin examples If ingested in excessive quantitiesà inhibit the absorption of minerals such as iron à lead to anemia This is because tannins are metal ion chelators, Tannic acid does not affect absorption of other trace minerals such as zinc, copper, and manganese in rats In sensitive individuals, a large intake of tannins may cause bowel irritation, kidney irritation, liver damage, irritation of the stomach and gastrointestinal pain. Protein sources:toxic amino acids - occur in the foliage and seeds of plant - Play a major role in determining the nutritional value of tropical legumes - Act as antagonist towards nutritionaly amino acids Protein sources:toxic amino acids - Mimosine or leucenol is an alkaloid, β-3-hydroxy-4 pyridone amino acid. It is a toxic non-protein free amino acid otherwise chemically similar to tyrosine - Although toxicosis has occurred in Australia, Papua New Guinea, Africa and Florida, it has not been recorded in any other tropical and subtropical regions.  Saponins Saponins have also antinutritional effect in metabolism of fats, reduction of blood, depression  Saponins Saponins are phytochemicals which can be found in most vegetables, beans and herbs. The best known sources of saponins are peas, soybeans, and some herbs Saponins have many health benefits: beneficial effects on blood cholesterol levels, cancer, bone health and stimulation of the immune system.  Glucosides This is the largest group of secondary metabolites. Substances consisting of sugar part and non-sugar part, so called aglycone. These two parts are connected by a bond of ether character – by glucosidic bond. These substances usually affect blood and circulatory system. These agents are not toxic themselves, but are easily hydrolysed in acid environment and release cyanic acid  Cyanogenic glucosides: Very common in plants, found in more than one thousand species in more than one hundred families. They are bitter and primarily act as repellents. We know more than 50 cyanogenic glucosides.  Cyanogenic glycosides - occur in legumes: linseed, lima bean, kidney bean, bamboo shots -may be relased by hydrolysis Amygdalin is the cyanogenic glycoside responsible for the toxicity of the seeds of many species of Rosaceae, such as bitter almonds, peaches and apricots. Cyanide contents of some foodstuffs Food HCN (mg/100 g) Lima beans 210–310 Almonds 250 Sorghum sp. 250 Cassava 110 Peas 2.3 Beans 2.0 Chick peas 0.8 Manioc (kasawa, cassava)- HCN - Hydrogen cyanide -We distinguish bitter and sweet types of manioc, bitter can contain up to 500 mg/kg of HCN  Almond, apricot, peach - HCN - Hydrogen cyanide HCN is very poisonous, but in plants occurs in quite low concentrations  Glycoalkaloids of potatoes Solanin -Potatoes are fourth most important crop-plant in the world -Toxic glycoalkaloids are found in the whole plant of potato Solanum tuberosum, -These alkaloids are so called steroid glycoalkaloids (SGA), or pseudoalkaloids, because their precursors are not aminoacids like in genuine alkaloids  Potatoe: By peeling we remove 60-95 % of solanin It is recommended not to expose them to light. Tuber reacts with rapid synthesis of alkaloids as a defence against stress Once formed, these alkaloids cannot be removed during storage in dark  PROTEASE INHIBITORS -Occurrence: mainly in legumes, but also in potatoes, cereals etc. -These inhibitors exist in food of animal origin too SUBSTANCES BINDING MINERALS - PHYTIC ACID AND PHYTATES: Phytic acid is a chelating agent, forms complexes with Fe, Cu and Zn, and can bind enzymes too (e.g. pepsin) – blocks absorption of these important minerals and causes starch to be less digestible – worse nutrition Natural Contaminants  Natural Contaminants There are three important sources: Raw materials of plant origin can become contaminated if they are mixed with toxic non-nutritive plant species. Raw materials of animal origin, mainly fish and milk, can also become contaminated if the animal has ingested toxic substances of natural origin. Contaminants of natural origin can be the products of microorganisms. Mixing of edible plants with toxic plants Several intoxications have been reported following the consumption of contaminated cereals. Contamination resulting from the intake of toxic substances by animals: Natural toxins in aquatic organisms Paralytic shellfish poisoning (PSP) is attributed to the consumption of shellfish that have become contaminated with a toxin or group of toxins from the ingestion of toxic plankton. Microbial Toxin: Mycotoxin Currently, a few hundred mycotoxins are known, often produced by the Aspergillus, Penicillium, and Fusarium. Toxic syndromes resulting from the intake of mycotoxins by man and animals are known as mycotoxicoses.  Microbial Toxin: Mycotoxin Mycotoxin contamination of food and feed highly depends on the environmental conditions that lead to mold growth and toxin production. Because of their chemical stability, several mycotoxins persist during food processing, while the molds are killed.  Aflatoxins Aflatoxins are the most important mycotoxins, which is produced by certain species of Aspergillus (A. flavus and A. parasiticus), which can growh at high temperatures and humidity levels. Aflatoxins are carcinogenic substances and may be present in a large number of foods. This toxin can cause cancer, cirrhosis of the liver. Aflatoxins The most common commodities contaminated are tree nuts, peanuts, and corn and cottonseed oil. The major aflatoxins of concern are B1, B2, G1, and G2 à usually found together in various proportions. Aflatoxin B is usually predominant, and it is the most toxic and carcinogenic.  Antinutrtional components in food PROF. UPP DR HAB. JOANNA KOBUS-CISOWSKA