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Dropping Calories, Maintaining Taste and Functionality

March 1, 2003 Teri Paeschke, Ph.D. Comments

Posted in Articles, Calorie Reduction, Healthy Foods, Carboxymethyl Cellulose, CMC, Cellulose Gum

According to statistics from the Centers for Disease Control and Prevention, Atlanta, obesity has increased from 12.0% of the population in 1991 to 19.8% in 2000. The National Health and Nutrition Examination Survey (NHANES) shows Americans are eating more, reporting that average caloric intake per day increased from 1,969 calories in 1978 to 2,200 calories in 1990. Despite the currently popular high-protein/low-carbohydrate diets, Chicago-based American Dietetic Association (ADA) spokesperson Dawn Jackson, R.D., Northwestern Memorial Wellness Institute, Chicago, says the ADA recommends “reducing intake of calories as the best way to obtain and maintain permanent weight loss.”

The increasing trend toward obesity, and its associated health risks, provides incentive and opportunity for the food industry to develop foods that are reduced in calories. The goal is to produce reduced-calorie foods that meet consumer expectations, something that eluded many of the fat-reduced and fat-free products introduced in the last decade.

Counting calories
The fat-free frenzy of the 90s is pretty much over. In the rush to join the bandwagon, many producers of reduced-fat foods found that their products fell short in taste and texture; few of these products have survived. One tactic was to replace fat with sugars and other carbohydrates to achieve a fat-free claim, sometimes providing the same amount of calories per serving as their full-fat counterparts. Consumers interpreted the low-fat and fat-free claims as “I can now eat as much as I want without guilt,” which was a mistaken idea as shown by recent weight statistics.

As the Atlanta-based Calorie Control Council maintains, “calories count.” A rose is rose by any other name and, “a calorie is a calorie is a calorie, whether it comes from fat, protein or carbohydrate,” says Jackson.

Calories are the units of energy that a food supplies, and calories derived from fats, carbohydrates and proteins are equivalent. Of course fat provides 9 kcal/gram, while carbohydrates and proteins provide 4 kcal/gram, but the energy that a calorie supplies from each of these sources is the same, regardless of its origin.

Some reduced-calorie products have already met with great success in the food industry. Reduced-fat milk, diet sodas and sugar substitutes are popular, but reduction of calories in food products with a higher level of solids, such as baked goods and dairy desserts, has proven more difficult. Calorie reduction in beverages is relatively easy, by replacement of sugars with water and high-intensity sweeteners. The complexity of replacing solids, such as fat and sugar, with noncaloric or lower-calorie ingredients requires not only the replacement of solids, but also the functionality of sugars, fats and related ingredients. For example, along with sweetness, sugars provide inexpensive bulk, control water activity (aw), increase shelf life, promote tenderness in baked goods, lower freezing-point depression and cause browning of heat-treated foods. Fats provide lubricity, texture, emulsification, a rich mouthfeel and a multitude of flavors. These are only some of the functionalities designers must replace.

Calorie reduction in high-solids foods usually requires a systems approach to address the functionality of each ingredient reduced or removed. No one universal replacement for calories, fat or sugars will do it all. After all, water, air and cellulose are the only ingredients that contain zero calories, and their substitution for constituents with multiple functionalities, such as fat and sugar, is usually limited. An arsenal of ingredients exists to reduce calories, but the trick is to match the functionalities of caloric ingredients with those of the calorie-reducers, while paying mind to the economic impact of specialty ingredients.

First, designers should identify a target calorie reduction and any other nutritional claims. Examine the major ingredients that make up a formulation and evaluate which of these contributes the majority of calories. Then determine their function(s) and identify what type of substitute ingredient will replace the functionality. Use formulation software to stage “what if” scenarios, along with some common sense to develop trial formulations. Several ingredients may be necessary to replace the functionality of major ingredients, such as fat and sugars. For example, fat provides emulsion stability in many types of products; substituting water, an appropriate emulsifier and a thickening agent, plus additional solids, might replace the emulsion capacity and bulk of the original fat.