FOOD APPLICATIONS FOR NATIVE AND MODIFIED STARCHES

IV. FOOD APPLICATIONS FOR NATIVE AND MODIFIED STARCHES

A. Native Starches

The dictionary defines carbohydrates as ‘‘any of various neutral compounds of carbon, hydrogen and oxygen (as sugars, starches and cellulose), most of which are formed by green plants and which constitute a major class of animal foods.’’ Around the world we find differing tastes and desires for what is considered palatable. The native starch for regional food application could be based on wheat, maize, potato, rice, arrowroot, or sor- ghum. Much of this dominance is due to climate, growing conditions, and history. What is preferred in the United States (primarily maize and wheat) would not be considered acceptable for general food use in Europe or Asia, and what is traditional to Europe is not always desirable in other sectors of the world (50). This continues all around the globe.

Native starches are usually used because of economics. In some instances native starch is added to foods for a specific functional property. It could include texture, flavor, and/or clarity—or lack there of ( Table 2 ). They should not be added to food systems as

a stabilizer for the water phase, at least not at this time. Possibly in years to come, with continued research and genetic engineering, we may see such functional properties contrib- uted from nonchemically modified starches.

One of the first characteristics associated with starch is the flavor aspect. This can and does limit native starch use in neutral or sensitive flavored foods. Even for flour, where wheat starch is a primary component, flavor can be an issue. But at this point there is a fact that must be noted. Although I have not been able to locate documentation to verify or dispute it, however I have studied many food products within the food industry and I contend that starch masks flavors to a lesser degree than sucrose. This was high- lighted during the introduction of high-fructose corn syrup in the 1970s for use in spoon- able salad dressings. During the replacement of sucrose with the liquid sweetener, many One of the first characteristics associated with starch is the flavor aspect. This can and does limit native starch use in neutral or sensitive flavored foods. Even for flour, where wheat starch is a primary component, flavor can be an issue. But at this point there is a fact that must be noted. Although I have not been able to locate documentation to verify or dispute it, however I have studied many food products within the food industry and I contend that starch masks flavors to a lesser degree than sucrose. This was high- lighted during the introduction of high-fructose corn syrup in the 1970s for use in spoon- able salad dressings. During the replacement of sucrose with the liquid sweetener, many

Consider now the texture aspect of native starches. In many instances it is directly proportional to the percent and the molecular size of the amylose molecule. As was dis- cussed earlier, amylose becomes significant when attempting to utilize native starches in processed food products. Amylose tends to cause gelling, or aggregates of starch crystal- lites. These aggregates generate grainy to very rigid textures from native starches. In starches that are predominately amylopectin (waxy), the texture can be short and smooth to long or stringy. They are also be referred to as cohesive. How can we take advantage of the extreme variability in textures produced by native starches? I’ve already mentioned dressings, but also consider such foods as confections, sauces, gravies, and fillings. De- pending on the strength of the gel or the contribution to flavor and/or texture of savory fillings these will most likely dictate your starch choice.

Native starches can also be used as a dry ingredient. If you were to reduce the moisture content of the native starch to less than 7% (redried starch), it could be added to mixes for moisture control as well as for providing some thickening and economics. Native starches can be and are used just as a source of carbohydrate, however as we see now there are many functional possibilities. One other very common use for native starch is that of producing powdered sugar. In this application it acts as a flow aid.

As the third characteristic of native starches, clarity (or opacity) can be advantageous (or in some cases cause a serious problem). Those products containing short chain amy- lose, such as the cereal starches generally contribute opacity to a finished food product. This goes along with the retrogradation process. For some foods this may not be a signifi- cant issue, however in many this change from clear is unacceptable. Gravies, sauces, dressings, puddings, and other savory foods usually are opaque. The foods requiring more clarity such as fruit fillings and jellies require the use of the waxy variety of starch. In some cases the longer chain tuber starches have been found to be functional.

For native starches that have not been modified, a food processor should only expect

a few hours of shelf-life. Physically modified starches have shown in some tests longer stability, but do not compare directly with the chemically modified starches as yet.

B. Modified Starches

With the introduction of modified starches to the food industry, starch usage in food sys- tems has increased dramatically over the past 50 years. One reason for this shift in use is the capability of modified starches to be utilized over a broad range of processing parameters, e.g., acidity, thermal conditions, and mechanical shear. Their stability through- out these parameters of processing and the other identified functional characteristics have lead to use increase. Compared to other ingredients within a food matrix (other than water), starch cost is proportionally minimal.

The modification of starch, as well as the residual components after modification are regulated worldwide. There are differing regulations depending on the chemical and/ or process used, the country of preparation, and location of use. It is very important to

be aware of all regulatory issues, restrictions, and definitions before utilizing a starch product in a food system for export. Surprises can be costly to the unaware.

Modified starches are typically used in foods around the world. They are added to thicken, stabilize, or texturize a food product. In actuality, they are used for many more functional characteristics. Prior knowledge of the product parameters, processing condi- tions, and other key factors will save time and expense.