File Name: biotechnology of food and feed additives .zip
Food additive , any of various chemical substances added to foods to produce specific desirable effects. Additives such as salt , spices , and sulfites have been used since ancient times to preserve foods and make them more palatable. With the increased processing of foods in the 20th century, there came a need for both the greater use of and new types of food additives. Many modern products, such as low-calorie, snack, and ready-to-eat convenience foods, would not be possible without food additives.
There are four general categories of food additives: nutritional additives, processing agents, preservatives, and sensory agents. These are not strict classifications, as many additives fall into more than one category. For more information on additives, see emulsifier ; food colouring ; nutritional supplement ; and preservative. Nutritional additives are used for the purpose of restoring nutrients lost or degraded during production, fortifying or enriching certain foods in order to correct dietary deficiencies, or adding nutrients to food substitutes.
The fortification of foods began in when iodine was added to table salt for the prevention of goitre. Vitamins are commonly added to many foods in order to enrich their nutritional value. For example, vitamins A and D are added to dairy and cereal products, several of the B vitamins are added to flour , cereals, baked goods, and pasta , and vitamin C is added to fruit beverages, cereals, dairy products, and confectioneries.
Other nutritional additives include the essential fatty acid linoleic acid, minerals such as calcium and iron , and dietary fibre. A number of agents are added to foods in order to aid in processing or to maintain the desired consistency of the product. Emulsifiers are used to maintain a uniform dispersion of one liquid in another, such as oil in water.
The basic structure of an emulsifying agent includes a hydrophobic portion, usually a long-chain fatty acid, and a hydrophilic portion that may be either charged or uncharged. The hydrophobic portion of the emulsifier dissolves in the oil phase, and the hydrophilic portion dissolves in the aqueous phase, forming a dispersion of small oil droplets. Emulsifiers thus form and stabilize oil-in-water emulsions e. Stabilizers and thickeners have many functions in foods.
Most stabilizing and thickening agents are polysaccharides , such as starches or gums , or proteins , such as gelatin. The primary function of these compounds is to act as thickening or gelling agents that increase the viscosity of the final product. These agents stabilize emulsions, either by adsorbing to the outer surface of oil droplets or by increasing the viscosity of the water phase.
Thus, they prevent the coalescence of the oil droplets, promoting the separation of the oil phase from the aqueous phase i. The formation and stabilization of foam in a food product occurs by a similar mechanism, except that the oil phase is replaced by a gas phase.
The compounds also act to inhibit the formation of ice or sugar crystals in foods and can be used to encapsulate flavour compounds. Chelating, or sequestering, agents protect food products from many enzymatic reactions that promote deterioration during processing and storage. These agents bind to many of the minerals that are present in food e. Food additive Article Media Additional Info. Article Contents. Print print Print. Table Of Contents. While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions. Facebook Twitter. Give Feedback External Websites. Let us know if you have suggestions to improve this article requires login. External Websites. Coeditor of Food Additives. See Article History. Learn about the myths and safety of monosodium glutamate MSG. Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now. Processing additives and their uses function typical chemical agent typical product anticaking sodium aluminosilicate salt bleaching benzoyl peroxide flour chelating ethylenediaminetetraacetic acid EDTA dressings, mayonnaise, sauces, dried bananas clarifying bentonite, proteins fruit juices, wines conditioning potassium bromate flour emulsifying lecithin ice cream, mayonnaise, bakery products leavening yeast, baking powder, baking soda bakery products moisture control humectants glycerol marshmallows, soft candies, chewing gum pH control citric acid, lactic acid certain cheeses, confections, jams and jellies stabilizing and thickening pectin, gelatin, carrageenan, gums arabic, guar, locust bean dressings, frozen desserts, confections, pudding mixes, jams and jellies.
Gum arabic from Acacia species. Gum is used as a stabilizing or thickening agent in food to increase the viscosity of the final product. Load Next Page.
Genetically modified foods GM foods , also known as genetically engineered foods GE foods , or bioengineered foods are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering. Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits when compared to previous methods, such as selective breeding and mutation breeding. Commercial sale of genetically modified foods began in , when Calgene first marketed its unsuccessful Flavr Savr delayed-ripening tomato. Genetically modified crops have been engineered for resistance to pathogens and herbicides and for better nutrient profiles. GM livestock have been developed, although, as of [update] , none were on the market. There is a scientific consensus     that currently available food derived from GM crops poses no greater risk to human health than conventional food,      but that each GM food needs to be tested on a case-by-case basis before introduction. However, there are ongoing public concerns related to food safety, regulation, labelling, environmental impact, research methods, and the fact that some GM seeds, along with all new plant varieties, are subject to plant breeders' rights owned by corporations.
Michael C. Falk, Bruce M. Chassy, Susan K.
It seems that you're in Germany. We have a dedicated site for Germany. This book review series presents current trends in modern biotechnology. The aim is to cover all aspects of this interdisciplinary technology where knowledge, methods and expertise are required from chemistry, biochemistry, microbiology, genetics, chemical engineering and computer science. Volumes are organized topically and provide a comprehensive discussion of developments in the respective field over the past years.
Algae are by far the most abundant primary producers, although some can be mixotrophic or heterotrophic. In biological sense, the term algae implies more divisions of lower plants which contain chlorophyll in cells and are typical inhabitants of aquatic biotopes, although they are quite widespread outside the aquatic environment Blazencic, , and on the basis of dimensions they are divided into macroalgae macroscopic algae and microalgae microscopic algae.
Коммандер спускался по лестнице, ни на мгновение не сводя с него глаз. Он быстро подошел к ним и остановился в нескольких сантиметрах от дрожащего Чатрукьяна. - Вы что-то сказали. - Сэр, - задыхаясь проговорил Чатрукьян. - ТРАНСТЕКСТ вышел из строя. - Коммандер, - вмешалась Сьюзан, - я хотела бы поговорить… Стратмор жестом заставил ее замолчать.
Бев Стратмор никогда его ни в чем не обвиняла. Она превозмогала боль сколько могла, но ее силы иссякли. Она сказала ему, что их брак исчерпал себя, что она не собирается до конца дней жить в тени другой женщины. Вой сирен вывел его из задумчивости. Его аналитический ум искал выход из создавшегося положения.
Смит кивнул: - Наш самолет в Малаге. - Он похлопал Беккера по спине. - Получите удовольствие, профессор.
- Бринкерхофф посмотрел на нее осуждающе. - Дай парню передохнуть. Ни для кого не было секретом, что Мидж Милкен недолюбливала Тревора Стратмора. Стратмор придумал хитроумный ход, чтобы приспособить Попрыгунчика к нуждам агентства, но его схватили за руку.
Она посмотрела на часы, потом на Стратмора. - Все еще не взломан. Через пятнадцать с лишним часов. Стратмор подался вперед и повернул к Сьюзан монитор компьютера.
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