Diet Trends Affect Processing

Diets that promise quick weight loss are the bane of nutritionists, who keep insisting that there is no magic approach except to eat less and exercise more. Nonetheless, fad diets are popular, and some may have influenced public food-buying practices enough to affect such industries as baking and pasta. In turn, food companies have developed new products or modified old ones to satisfy customers influenced by popular diet suggestions.

Low-Carbohydrate Products
Both the Atkins and South Beach diets emphasize reduced carbohydrates, so companies offer reduced-carbohydrate versions of their products. Examples include beer, bread, fruit juice, and others. Making such products so they are acceptable in taste can be a challenge.

• Low-Carb Bread. Bakers have offered low-calorie bread by reducing portion size (thinner slices) and by replacing wheat flour with something else. One approach was to use highly refined cellulose fiber, essentially very fine paper pulp, which, of course, is indigestible. There is some sophisticated technology involved in producing a palatable loaf of white bread with about one-third less flour and a much less functional ingredient. The product was relatively successful until a United States senator described it as having sawdust in it. Despite efforts to counter that unfair description, the product soon died. The benefits of higher fiber in the diet were only then becoming well known and so were not enough to salvage the product. However, use of purified cellulose in foods, especially in baked goods, is again being suggested.

Modern efforts to produce low-carbohydrate bread use wheat protein isolate and refined soy and oat fiber, according net to Scott Gantwerker, Vice President, Research & Development and Quality for Pepperidge Farm, Norwalk, Conn. Pepperidge Farm has long offered a very thinly sliced loaf of white and wheat bread, called Very Thin, as one approach to reducing portion size, but the reduced-carbohydrate bread is new. The company also offers whole-grain breads and soon will produce whole-wheat bagels and mini bagels.

As with most such products, the desire of manufacturing is to use existing equipment as much as possible. However, modifications need to be made in mixing and baking to achieve desired results. In baking, it is common practice to hold dough in troughs to allow it to relax after mixing and to compensate for interruptions in the subsequent steps of rounding, portioning, proofing, and baking. Gantwerker points out that the low-carbohydrate bread is less tolerant to floor time and thus more attention must be paid to scheduling, maintenance, and smooth operations.

Sara Lee is emphasizing whole-grain breads in its fresh-baked lines, but the company has made few changes in its frozen products.

• Low-Carb Fruit Juice. The carbohydrates in fruit juices are the naturally occurring sugars, which cannot easily be removed. To offer a fruit juice–based beverage with fewer carbohydrates requires dilution with water and replacement of the missing components that contribute to flavor and mouthfeel. Thus, a substitute juice is composed of water, flavor (often derived from the natural juice or fruit), something to add body for mouthfeel, citric (or other) acid to balance the sweetness and maintain proper flavor, and one of several artificial sweeteners, such as sucralose or acesulfame K. Compared with extracting, pasteurizing, and packaging single-strength juice, the reduced-carbohydrate product requires additional formulation and mixing. Synthetic sweeteners require care in formulation because of their potency and cost. Often they are dusty and difficult to disperse.

Fruit juices are governed by numerous labeling regulations intended to prevent adulteration and deception. Thus, anything other than straight fruit juice is called a beverage or drink. Actual fruit juice content is usually declared and can range from as low as 10% for some inexpensive drinks to as high as 100% in straight juice. To reduce carbohydrate content by 50% would require replacement of about 50% of the juice content.

• Low-Carb Beer. The calories in beer come from alcohol and residual carbohydrates left from the grains that are fermented. Light beers are typically made with dextrose from corn instead of rice or corn as adjuncts to malted barley. Some light beers use special enzymes to obtain higher conversion of starch to sugar, permitting greater dilution with water and thus lowering calories. Low-carbohydrate beers use versions of these same techniques, either using fewer complex carbohydrates in the first place or converting them more thoroughly. Such beers normally have a thinner body or mouthfeel, since the carbohydrates contribute to the viscosity of the liquid. The same equipment used for other beers is used for these products.

Low-Calorie Through Fat Replacement
Replacing fat in foods is an effective way to reduce calories but can be a challenge because of the many roles that fat plays, especially its impact on mouthfeel of many foods. One of the more successful fat substitutes is Simplesse, developed originally at NutraSweet by Norman Singer, now president of his own consulting firm, Ideas Workshop, Northbrook, Ill. (phone 847-412-1411). Singer describes the fat substitute as consisting of microspheres of whey protein, about one micron in diameter—about the same as that of fat droplets in many emulsions, such as ice cream and salad dressings.

Simplesse is used in frozen desserts, salad dressings, and baked goods. It cannot be used for frying.

Singer discovered the material in the course of processing whey protein concentrate through more or less conventional dairy pasteurization and homogenization equipment. He determined that heating caused the proteins to coagulate and agglomerate, while the shearing of homogenization kept the particles to the desired size range. The optimum raw material is 50–55% whey protein concentrate. The resulting product is a viscous paste, something like double cream.

Early efforts to persuade food processors to adopt the ingredient met resistance because of inexperience with incorporating such a paste. Most food ingredients are either dry or pumpable liquids. Thus, to gain acceptance, the fat substitute was dried to a powder, which requires high-shear mixing to disperse. In addition, it is a good air entrainer, which is not always desired in products where it is used, so the mixing must avoid air.

As with juices and other food products, reduced-calorie frozen desserts must be carefully labeled. Ice cream has a standard of identity which requires at least 10% butterfat. Products with less are called ice milk or just frozen dessert. Products with fat from a different source, such as some that are still made in Europe, have other names. Singer commented that Simplesse has a positive effect on the texture of such products. Other fat substitutes from whey protein, made by different processes, do not have the distinctive microsphere character of Simplesse and so do not function as well, according to Singer.

Some other fat replacers have included triglycerides in which long-chain fatty acids are replaced with shorter fatty acids, lowering the caloric content while retaining many fat-like properties. These usually require some processing adjustments but may not require much label change.

Minimizing Equipment Investment
In general, food processors try to minimize investment in equipment. When formulations change for new products or to incorporate a new ingredient, the usual practice is to adjust process variables as necessary while using the same equipment. These variables may be time of mixing, temperature, pressure, hold time, baking time and temperature, freezing time and temperature, and others that may be available.

As mentioned earlier, new ingredients are best accepted if they are in familiar form and can be measured and handled in known ways. Given that fads come and go, as may already be true for low-carbohydrate foods, it is wise to limit process and packaging changes. However, changing portion size may well be a popular move.

by J. PETER CLARK
Contributing Editor
Consultant to the Process Industries
Oak Park, Ill.
[email protected]