Introduction:
Fat substitutes are in fact substances used from long ago and only new methods have been developed for their application. For instance, Carrageenan which has been used as stabilizer and emulsifier since 1960s onward currently serves as fat substitute. Another group of them had formerly no application but have been derived from main compounds, and, the third type is the substitutes which are a blend of main substances, like Olestra.
Aiding reduction of saturated fat level, reduction of energy consumption for health improvement, enhancement of food deliciousness without increasing fat amount and lowering risk of obesity, and specific and chronic diseases are among the intents pursued in consumption of fat substitutes. Fat substitutes have fewer calories for the food and the consumers control their calorie intake level via eating the respective foods. With a 10% reduction in fat content of foods, the daily calorie intake is reduced by 238 kilo calories. Therefore, utilization of fat substitutes in foods will be accompanied with reduction of fat content and reduction of energy intake. Fat substitutes are classified in three groups: protein-based, fat-based, and carbohydrate-based fat substitutes.
Each group has their own advantages and disadvantages and exhibit different functional properties. In dietary systems, further desirability can be achieved using two or several fat substitutes.
Carbohydrate-based Substitutes
This group has a creamy fatty state. They absorb water and stabilize food and increase its volume and stability. In this substitution, the calorie intake is also decreased for 5 calories per each gram in addition to reduction of fat content. Their substantial application is as stabilizer and fixators. They are utilized in many food products such as dairy industries, frozen desserts, sauces, salad icing, processed meat, cooking foods, spreads, chewing gums, and sweets and candies. Nonetheless, they are not appropriate to be used in frying food products. Guar gum, gum Arabic, Xanthan gum, carrageenan, poludextrose, treated starch, oat and wheat fiber are in this group.
Maltodextrin is a volumizing agent and does not require any adverse reaction. Polydextrose establishes a high viscosity in the solution and is accompanied with oral perception and creamy state in low-fat product. Maltodextrin is used as substitute of fat and sugar in foods. Maltodextrin and polydextrose are used in cooking industries.
Protein-based Fat Substitutes
For this substitution, proteins are heated and then rotated inside a mixer severely until very tiny particles referred to as “micropartciles” are formed out of proteins at the end. The products of this group are obtained from proteins of whey, milk, and egg which contain 1-4 kilocalories per one gram of their consumption. The acquired protein microparticles are tiny and powdery particles that can create desirable oral sense and similar to fat. This group is generally mixed with water and can be used in lower fat amounts. For example, it is possible to replace 3 grams of fat by 1 gram of protein-based fat substitutes. This group is not suitable for use in fried foods but can be utilized in dairy industries like fat-free ice-cream, frozen desserts, and milk shakes. Protein mixture is another group of this substitute group and consists of a blend of plant and animal proteins, gum, food starch, and water used in frozen desserts and baking industries.
Whey protein concentrate is one of the fat imitators and is broadly used in emulsions with reduced fat alone or in the presence of other fat imitators. The commonly used concentrates include the whey concentrate 34 and 80 (containing 34 and 80% of protein). They exhibit diverse functional properties and similar to fat such as gel formation, emulsion formation, water absorption, viscofication, and adhesiveness.
Fat-based Fat Substitutes
This group can entail chemical variations of fatty acids that reduce the calorie intake even up to zero. Fat-based emulsifiers and substitutes include salatrim and olestra which have functional properties analogous to fat and generate nocalorie and are not absorbed when passing through the body.
Mono- and di-glycerides also are fat-based fat substitutes. Emulsifiers are fat-based substitutes which are used together with water and replace partially or completely the shortening in mixture of cake, pan, icing, vegetables, and dairy products. They generate calorie similar to fat but are applied in product formulation at a lesser extent, which ultimately brings about reduction of fat and energy content.
There are several classifications for fat substitutes. Fat substitute is an additive that acts like fat and traditional oil and can replace the fat at a 1 to 1 weight ratio, like olestra. Fat analogues are compounds which possess many of fat properties but different nutritional and absorption properties such as caprenin. Developer fat has the optimal functional properties of the fat and therefore reduces the fat content in food products; e.g. emulsifier.
Fat imitators are additives which mimic one or several functional and sensory properties of fat. They are based on protein, carbohydrate and fat that can be used individually or in blended form. They contain about 0-9 calorie per gram of energy and are accompanied with water absorption, oral sense, and softening similar to fat.
Protein-base and brine-soluble fat substitutes can be utilized in meat products.
Applicable Types:
CKF stabilizer and fat substitute is a set of cellulose gel, konjac, and Xanthan whose mixture has a synergistic effect in solution with cold water. If high stress is applied while mixing the gum in the cold solution, a heat reversible gel will be formed. Micro-crystallized cellulose in gum mixture helps emulsion and foam stabilization and creates a physical carrier and inhibitor against emulsion accumulation. They are very suitable for mayonnaise and sauces having very low fat content.
Olestra with common brand name “Olean” is a compound connected to sucrose molecule via 6-8 acid bonds. Increase of fatty acids enlarges this molecule making it unabsorbable. Olestera has functional properties similar to fat and is also in frying as well. Olestra causes blockage of stomach veins, stool reduction, and prevents from absorption of fat soluble vitamins.
Depending on fat source in sucrose polyester, olestra can be found in liquid or solid states at room temperature. It has organoleptic and thermal properties analogous to fat but is not decomposed by stomach lipase and pancreas. And it is not absorbed in the digestive tube either because of its very long molecule. Therefore, it is not metabolized for energy generation.
Producers use olestra at situations where addition of fat soluble vitamins (A, D, E, and K) is required.
Caprenin is composed of behenic, capric, and caprylic acids which lowers level of bad blood cholesterol (LDL).
Salatrim which is alias for short and long-chained triacylglycerides contains stearic, palmitic, and acetic acids. Salatrim is used in production of flavored chocolates and crisps. It has undergone reduction in its level of short-chained fatty acids as well as 50% of its stearic acid. This fatty acid compound is free from trans. Salatrim replaces hydrogenated fat and acts as shortenings. This product is used in baking and cake industries. All fat substitutes are in GRAS list and confirmed by FDA (Food and Drug Administration).Olestra was primarily introduced in 1996 for utilization in crisps and it shall be mentioned on the product package as mandated by FDA. In 2003, following assessments conducted, FDA relieved the necessity for mentioning olestra presence on the packages of food products. Only partial amount of fat soluble vitamins which are not absorbed by olestra shall be added to the respective foods. In this case, the respective vitamins are distributed in olestra and enter the body via the same substance.
Benefits of Fat Substitutes
Fat substitutes can leave an overall effect on the quality of diet should they constitute a part of individuals’ general herbal diet. For example, nutrients can be received by intake of salad sauce whose formulation contains fat substitute while the calorie level is low.
In meat products, the respective substitutes do not merely act as reduction agents of fat and energy levels but also enhance the antioxidant value of the food.
Fat substitutes based on protein derived from milk powder, whey, soybean and legumes can increase protein content of foods. The substitutes in margarine, spread, and dessert products reduce levels of fat, saturated fat, and trans- fatty acids.
Fiber-containing substitutes such as inulin, lupin fiber, and beta-glucane are able to enhance nutritional value and increase dietary fiber amount.
Yogurt with reduced fat can be obtained by replacing some amount of milk fat with fat substitutes. Fat substitute particles are apparently larger than milk fat globules.
A researcher figured out that soft texture and desirable oral sense of fat-free yogurt can be achieved via simultaneously using the maltodextrin derived from enzymatic treatment of potato starch and treated waxy starch.
Utilization of whey protein concentrate together with treated whey protein would create a yogurt with textural properties similar to high-fat yogurt. Merging protein-based and carbohydrate-base fat substitutes and their application in yogurt is accompanied with lower hardness and adhesiveness compared to completely fatty yogurt.
In biscuits, fat content was reduced from 20% to 10, 8, and finally 6% following reduction of calorie level. The modified rheological properties in dough were analyzed using water absorption measurement device, Brabender farinograph, and Texture Analyzer. With decrease in fat level, dough hardness increased as well as the dough development time. Fat replacement by equivalent amount of maltodextrin and polyester and polydextrose reduced dough hardness and stability. Addition of monostearat and guar gum positively affects hardness and stability.
Conclusion
Nowadays, several solutions are assessed for reaching to a healthier food, and at the same time, having favorable sensory properties and marketability. Use of fat substitutes is among the improved circumstances which bring about desirable properties for the product beside lowering the intake calorie level. Various fat substitutes are utilized in food industry.
References
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10-www.gumtech.com 2009/4/24