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Bakery additives: Usage of protein as fat replacers

Friday, 18 November, 2016, 08 : 00 AM [IST]

Dipanshu Gakhar

Introduction
Fat is the easiest and the high source of energy in our daily diet providing 9kcal/g compared to any other component of food. Fat contributes maximum to the sensory characteristics of the food while enhancing the textural properties of the food. The most popular processed food products with high fat content are manufactured by bakery and dairy industries. It is also the triggering factor present in any food that makes people relish it.

However the current scenario shows that the consumption of high amounts of saturated fats leads to obesity, cancers, diabetes and high blood pressure. Some recent WHO global estimates in 2014 alone show that 1.9 billion adults aged 18 years and older were overweight while 600 million adults were obese. The worldwide prevalence of obesity has been doubled between 1980 and 2014. Therefore there is an urgent need to substitute fats with a healthy nutritional component and thus fat replacers can be a healthy alternative for most of the food processing industry.

Fat in Bakery Products and its Uses
Fats in bakery products provide aeration of the dough that acts as leavening agent, lubricant to avoid sticking of the dough on the surfaces of the equipment, texture that involves tenderness and reduced brittleness, flavour, mouthfeel, shiny appearance to the final product and increases the feeling of satiety during meals. The amount of fat in a product depends on the type of the product to be made. Some food are less in fat content like breads while some are high in fat content like fried doughnuts.

The following table depicts the range of fat content in some bakery products according to formulas reported by Matz (1992).

Table 1: Fat Content of Dough and Batters of Typical Bakery Foods

Table 1: Fat Content of Dough and Batters of Typical Bakery Foods
Product	Typical Fat Content on Dough Basis (%)
Breads	1-3.5
Pound cakes	7-17
Layer cakes	10-12
Unleavened cookies	16-32
Leavened cookies, crackers and biscuits	9-13
Doughnuts	5-7
Danish	27-39
Puff pastry	33-38
Crust of fruit pies	24-38

What are Fat Replacers?
The current trend of replacing the fat in food products adopted majorly by industries are some of the common techniques such as substituting fat with water, air or by using lean meats while replacing whole milk with skimmed milk. Additionally frying of food items that contain high amount of saturated fats can be replaced by baking in manufacturing of food products. Fat replacers are substances that mimic the properties of fat in food. An ideal fat replacer tastes and resembles closely to fat with fewer calories. Fat replacers can be employed in foods such as
baked foods, cheeses, sour cream, yogurt, margarine, salad dressing, sauces and gravies. Fats can be replaced in foods by reformulating the foods with different types of fat replacers especially lipid, protein, or carbohydrate-based ingredients, individually or in combination.

Protein-based Fat Replacers
Protein-based fat replacers consist of low molecular weight proteins that provide a fat like structure and hence substantially add to mouthfeel while providing energies below 4 kcal/g. Proteins denature at high temperature and therefore difficult to be employed as fat replacers at elevated temperatures. However there are certain processing techniques wherein they can be formulated in bakery products as fat replacers.

Types of Protein-Based Fat Replacers
?   Microparticulated proteins are round particles of approximately 1µm diameter prepared via simultaneous pasteurisation and homogenisation. Milk, egg white and whey are used for the preparation of microparticulated proteins. Whey Protein Concentrate either 35% or 50% is used in the preparation of fat replacers. Some of the common whey-based microparticulated proteins are available in the market by the brand name of Simplesse, and are extensively used in products such as ice cream, butter, margarine blends and in baked foods. These microparticulated proteins (as fat replacers) are manufactured from whey protein concentrate by a patented microparticulation process developed by the NutraSweet Kelco Co. (a unit of Monsanto Co., San Diego, Calif.).

?   Modified Protein Concentrates is derived from whey or milk protein concentrate under controlled thermal denaturation. The main marketed product is Dairy-Lo. Modified protein concentrates improves the stability of the emulsions of the low fat food and also enhances the texture and flavour of the resulting product. It has the ability of preventing shrinkage and icing.

?   Other protein-based fat replacers employ mostly egg and milk proteins. Milk protein hydrolysates provide creaminess and enhance textural properties in reduced fat dairy products. Corn and soy protein isolates are used to prepare these proteins that are majorly used in meat patties. The marketed products are K-Blazer, Ultra-Bake, Ultra-Freeze, Lita.

The table 2 depicts different types of protein-based fat replacers with their trade names and
their functionality in foods.

Table 2: Types of Protein-Based Fat Replacers, Trade Names and Functional Properties
Type	Products or Trade Names	Functional Properties
Microparticulated Proteins	Simplesse	Emulsion Stabilising, Mouthfeel
Modified whey protein concentrate	Dairy-Lo	Emulsion Stabilising, Mouthfeel
Other proteins (Similar mouthfeel to microparticulated protein but made by a different process)	K-Blazer , Ultra-Bake, Ultra-Freeze, Lita	Emulsion Stabilising, Mouthfeel

Application of protein-based fat replacers in bakery products
Protein-based fat replacers when employed in bakery products impart a significant change in physical, textural and sensory properties. They are processed in combination with other components like carbohydrates and emulsifiers in order to impart desirable characteristics to a product like cookies, breads, cakes and muffins.

A 1:1 blend of carbohydrate and protein mixture (Shukla 1995) acts as thickening and moisture retention agents. These blends of proteins and carbohydrates increase the batter viscosity that helps in retention of air bubbles and as a result product with a better texture is obtained. When high levels of emulsifiers are added to these products, the lubricity and aeration increases which absorbs an adequate amount of water while maintaining the moisture in the product. Proteins with emulsifiers are employed in fat-free products in order to provide reduced fat products because protein-based ingredients are hydrophilic and hence cannot be used as laminated media. In such cases emulsifiers in the products, especially in croissants act as laminated media. Although formulation of complete fat-free products is impossible as the
emulsifiers used in the fat-free products are fats only.

Changes in Bakery Products on Fat Replacement

?   Physical properties of the bakery products consist of evaluating moisture content, water activity, volume and colour. Protein-based fat replacers bind water strongly and hence more water is required for dough development. The benefit of this property of protein is that they bind water in the final product which reduces the chances of staling. Eventually a product obtained by Simplesse resulted in increased moisture content (34-36.3%) and water activity (0.91-0.93) compared with full-fat food (30.5% and 0.90) (Savas 1999, Theleriti 2000). Hence, due to high water activity the bakery products with protein-based fat replacers are also prone to mould growth. Fat added to the dough increases the volume of the dough by gas retention and therefore the fat replacers should also mimic this property. The colour of the final bakery product is not significantly different when fat replacers are used up to 35%.

?   Textural characteristics are mostly based on the sensory evaluation of the bakery products. Textural properties are determined by Texture Profile Analysis. The lowering of the fat content of the bread without any addition of the fat replacers results into increased hardness of the product. The removal of fat without any addition of fat replacer resulted into brittle cookies while replacement of fat by fat replacers resulted into a more brittle cookie. The addition of Simplesse decreased the hardness of the cookies. Addition of Simplesse (2.5% and 5%) on bread formulation increased the hardness of the bread.

?   Sensory properties of the bakery products also vary depending on the amount of fat replaced by fat in a bakery product. Generally reduced-fat foods receive lower evaluation scores in sensory evaluation as compared to the full-fat bakery products; therefore partial replacement of fat by fat replacers forms an acceptable product which receives a comparable evaluation score. Pszczola (1994) reported that Simplesse bakery blends were used in low-fat cakes, muffins, and brownies for fat replacement up to 93% and did not affect the full-fat taste.

Conclusion

Fat in an individual's diet should not be eliminated entirely as it is an important source of energy, responsible for transporting fat-soluble vitamins A, D, E and K and also nevertheless contributes to satiety, flavour and palatability of the diet. Overall, fat is an important part of an individual's diet but an excess of fat brings along a great risk to health and hence should be reduced or replaced to maintain good health. Fat replacers provide good taste and consumer acceptable foods which help allow them to retain dietary recommendations for reduced fat intake and to lose weight. Products containing fat replacers can also be consumed by people with diabetes making it easier to consume while adhering to a low calorie diet.

(The author is from NIFTEM. He can be contacted at dipanshugakhar77@gmail.com)