Food manufacturers often use hydrogenated fats as functional ingredients to improve the shelf-life of food materials. The chemical process through which hydrogenated fats are produced is termed as fat hydrogenation. Essentially, this process involves addition of hydrogen atoms to a double bond existing between carbon atoms in a fatty acid chain, which turns unsaturated fats into saturated ones (Leigh).
During fat hydrogenation, hydrogen gas is forced into unsaturated fats such as oils at a very high temperature (250 to 400oC) and pressure in the presence of a metal catalyst such as nickel, copper, zinc or platinum. The high temperature allows for the metal and gas to bond. The metal atoms also bind to carbon atoms in the fatty acid chain permitting hydrogen atoms to place themselves between the carbon atoms carrying a double bond. Thus, the double bonds become saturated with hydrogen atoms turning the unsaturated fat into a saturated one (“When is”).
The advantage of hydrogenating fats is that the process produces fats that do not oxidize easily thus increasing the shelf-life of food products considerably. Since hydrogenated fats are ‘plastic’, these fat molecules do not separate quickly and remain semisolid or solid at room temperatures. This proves beneficial for food manufacturers and consumers as it facilitates storage and transportation (“When is”).
Unfortunately, when an unsaturated fat is hydrogenated, there is no control over where the hydrogen atoms get added to the fat molecule. This results in the production of an unnatural fat mixture that contains trans fatty acids. The human body is not adapted to utilizing unnatural, trans fats like it does the natural cis fats. As a result, these fats remain relatively undigested in the system, increasing the risk for diseases (“When is”). Importantly, trans fats raise LDL or ‘bad’ cholesterol levels and reduce HDL or ‘good’ cholesterol levels in the body, which greatly increases the risk for heart diseases. On the whole, during hydrogenation, the nutritional and physiology-related functional values of oils are lost which makes them unhealthy for human consumption (Leigh).
Strategies to Lower Fat Intake Without Affecting Diet Palatability
Fat is a key food component as it contributes greatly towards the flavor and body of foods, which in turn affect their palatability. However, fat is the most concentrated energy source in the diet and its excess consumption is known to increase the risk for obesity and associated diseases. Hence, nowadays a lot of stress is being laid on consuming low-fat foods. For food manufacturers, this proves to be a challenge, as they have to make foods that are low in fat and yet have the same palatability as their fat-rich counterparts (Akoh 47).
Some common strategies used to lower fat content in foods without affecting the diet palatability include substitution with air or water, using lean meat cuts in frozen entrees, using skim milk instead of whole milk in desserts and baking instead of deep-frying snack foods such as chips and fries. Food manufacturers also use certain chemicals called as fat replacers to reduce fat intake from foods without affecting their palatability. These fat replacers that are lipid, carbohydrate or protein based, either replace (fat substitutes) fats in foods or mimic (fat mimetic) their organoleptic properties (Akoh 47).
Some examples of fat substitutes are lipid-based carbohydrate fatty esters, sucrose fatty acid polyesters or Olestra, polyol esters and exterified propoxylated glycerols, which are used to lower fat content in foods such as cake frostings, confections, spreads, shortenings, frozen desserts, dairy products, margarine and baked products (Akoh 49).
Fat mimetics can be derived from several protein sources such as whey, egg, soy, milk, wheat gluten and gelatin. Simplesse, a whey protein-based fat mimetic, is used to mimic fats in frozen desserts, sour cream and cheese spreads. Carbohydrate-based fat mimetics are derived from starches, gums, pectin and cellulose that lend a similar mouthfeel and texture to food products such as reduced-fat cookies, salad dressings, soups, baked goods, sauces and dairy products (Akoh 51).
Works Cited
Leigh, Katie. “The Process of Hydrogenation.” eHow. Demand Media, n.d. Web. 6 Apr. 2014. <http://www.ehow.com/how-does_5311451_process-hydrogenation.html>.
“When is a Vegetable Oil not a Vegetable Oil? When it’s a Plastic.” Natural-health-information-center. Natural Health Inforamtion Center, n.d. Web. 6 Apr. 2014. <http://www.natural-health-information-centre.com/hydrogenated-fats.html>.
Akoh, Casimir C. “Fat Replacers.” Food Technology 52.3 (1998): 47-53. Web. 6 Apr. 2014. <http://www.ift.org/~/media/Knowledge%20Center/Science%20Reports/Scientific%20Status%20Summaries/fatreplacers_0398.pdf>.
