Chemical food preservation
Chemicals are now commonly added to food to prevent spoilage. Chemical preservatives include free radical scavengers also known as antioxidantssuch as vitamin C and compounds such as BHA butylated hydroxyanisoleand bacterial growth inhibitors, such as benzoic acid, sulfur dioxide, and sodium nitrite NaNO 2.
Unlike natural food preservatives some of the chemical food preservatives are harmful. Hyperactivity only increased moderately, and it was not determined if the preservatives, colorings, or a combination of the two were responsible for the increase.
The Romans used a lot of dry fruit. Thus other methods were needed to preserve food reliably for transportation over long distances and for longer shelf life.
Explain chemical method of food preservation
Sulphur dioxide is used as a gas or in the form of its sulphite, bisulphite and metabisulphite salts which are powders. Also the freezing, boiling, smoking, salting are considered to be the natural ways of preserving food. Drying prevents yeasts and bread molds Rhizopus from growing by removing moisture so bacteria cannot grow. These countries have also proven useful in case studies surrounding chemical preservatives, as they have been only recently introduced. Microorganisms ferment the starch-derived sugars into alcohols. Studies have found that there is no convincing scientific evidence that the low dose of thimerosal as a preservative in vaccines causes harm, except for possible minor reactions like redness and swelling at the injection site. Some spoiling is caused by such microorganisms as bacteria and mold.
Preservation of food products containing chemical food preservatives is usually based on the combined or synergistic activity of several additives, intrinsic product parameters e. They are then cooled forming a vacuum seal which prevents microorganisms from contaminating the foods.
Water evaporating through earthenware jars was used as a coolant in B.
Chemical methods of food preservation ppt
Sodium nitrite is a preservative used in lunch meats, hams , sausages , hot dogs , and bacon to prevent botulism. Preservatives kill, prevent, or slow the growth of microorganisms , particularly bacteria and fungi, which may cause disease or infection. One of the most ancient methods of food preservation is sun- or air-drying. Smoked meat for example has phenols and other chemicals that delay spoilage. Irradiation currently extends the shelf lives of foods such as strawberries. The invention of canning by Nicolas Appert enabled commercial preparations of foodstuffs. Parabens are derived from para-hydroxybenzoic acid PHBA , which occurs naturally in many fruits and vegetables. Jars of fruit preserved with honey have been found in the ruins of Pompeii, Italy. This is also how fruits are fermented into wine and cabbage into Kimchi or sauerkraut. Chemical preservatives include free radical scavengers also known as antioxidants , such as vitamin C and compounds such as BHA butylated hydroxyanisole , and bacterial growth inhibitors, such as benzoic acid, sulfur dioxide, and sodium nitrite NaNO 2. Ascorbic acid and tocopherol , which are vitamins, are common preservatives. Food Preservatives Photo by: Ziablik Most foods contain enzymes or natural chemicals, such as acids or alcohols, that cause them to begin to lose desirable characteristics almost immediately after harvest or preparation. Words to Know Additive: A chemical compound that is added to foods to give them some desirable quality, such as preventing them from spoiling. The consumer can be certain of not running any risk by partaking foods which contain preservatives.
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