The Great Cover-Up: Batters, Breadings and Coatings

• Flour breaders. Most of these products consist of wheat flour, although they might contain corn flour, starches, gums, coloring agents and seasonings. This breader creates an uneven, home-style appearance.

• Cracker meal breaders. These crumbs are produced from a cracker-type formulation, but generally are not leavened. Dough is extruded in a sheet, and either baked out completely, or baked to a higher moisture, requiring a secondary drying after grinding. This sheet is ground into crumbs; these may be sieved for size. Exact size depends on the manufacturer, but is generally classified as fine (60 to 140 mesh, U.S. sieve), medium (20 to 60 mesh, U.S. sieve) and coarse (4 to 6 mesh, U.S. sieve). Cracker meal normally has a hard, crunchy texture, but changing the formulation can modify this somewhat. Varying the amount of colorants and the level of browning agents can create a color range from white or cream to a reddish brown.

• American bread crumbs (ABC). Typically used on raw-breaded or partially fried products destined for oven-heating or frying, ABCs come from baked loaves of yeast-raised bread. After baking, the loaves are dried to the required moisture, then ground and sieved into fine, medium and coarse sizes. The crust provides darkened highlights. This crumb has a crisp texture that is less tough than a cracker meal crumb.

• Japanese, or oriental-style bread crumbs (JBC). This type of crumb, sometimes known as a Panko-type, begins life as a traditional yeast-raised bread dough. However, instead of oven-baking, manufacturers use alternative methods, either cooking via microwaves or using electrical resistance. These methods cook the bread rapidly and leave little or no visible crust. JBCs have a more elongated shape than ABCs. They also exhibit a porous structure that results in a tender/crisp texture. By modifying the process, the characteristics of the crumb structure and the textural characteristics can be altered.

  "The reason we went to the microwave process was to make a more resilient crumb for breading applicators. This patented process gives more resiliency while still having the same finished product attributes," adds George Manak, director of marketing, coating systems at Griffith.

  Technologists at Chicago-based Newly Weds Foods, Inc. also are looking at something described as "dimensionalized" coatings by Mary Jo Corcoran, manager of marketing for its batter and breading division. "We've worked with adding bean thread noodles. We have a chicken coating that we've added potato shreds to that give it some visual appeal."

  Adhesive batters gained the name for a very simple reason - like Mom's egg and milk dip, they provide an adhesive layer between substrate and outer breading layer. They can be formulated with wheat flour, corn flour or starch.

  "Most of the batter systems use about three different starches on average," says Dot Gentile, development chemist, National Starch & Chemical Co., Bridgewater, NJ. "Different starches influence different properties, plus the rest of the system creates certain effects. We can use starches as tools to change those properties from the original system."

  Adding other carbohydrates, especially gums, also can improve adhesion in batters. Film formers such as methylcellulose (MC), hydroxypropyl methylcellulose (HPMC) and carboxymethylcellulose (CMC) have been used in this capacity. MC and HPMC exhibit thermal gelation and will form a structure upon heating. Other gums, such as alginates, gellan gum and carageenan can form a gel structure in the presence of ionic salts.

  "We have to maintain a fairly tight control on cold water viscosity of the dry mix, because in the plant they want to keep the process as consistent as possible with the addition of water to the dry mix," says Joachim Baur, senior principal food technologist at Griffith. "Typical QA tests would be a Brookfield viscometer reading. Thicker batters would use a Bostwick apparatus. Equipment like the Zahn cup or the Stein cup is used in the industry as a quick, easy and inexpensive method."

  Tempura batters and similar coatings, such as fish-and-chip batters, require adhesive qualities because they have to stick to the substrate, but they also serve as the outer layer of coating. Tempura batters share similar ingredients to adhesion batters, with one important difference - they contain leavening agents greatly influencing texture. Sodium bicarbonate, combined with an appropriate leavening agent, produces carbon dioxide when exposed to heat. This creates the characteristic "open" structure.

  Formulation can depend on the specific application. "If you were going to raw-bread or eliminate a frying step, you would use more browning agents such as whey or dextrose," recommends Jeff Kirn, director of sales, coatings and flavorings division, Kerry Ingredients, Beloit, WI. "You could use colored crumbs that are ground up as an additive. You can use paprika and annatto as well."

  "Sometimes if you have a very wet surface, if you put a batter directly on that, it will tend to be diluted down," explains Kubica. "Or you might want to get a little more pick-up than you would normally get with just batter and breading. So, if you use a predust, you can increase that pick-up and put some functional ingredients in that help the system hold together and adhere better. There can be specific predusts for specific substrates."

  "People are also looking for enhanced coatings that can be accomplished through breadings or enhanced texture in batters, or a combination," Manak adds. "We are finding in retail that people are no longer accepting trade-offs in terms of texture just because the product comes out of an oven. Food manufacturers are now demanding the same texture from ovenized product that they would get from a fried product."

  "Working closely with the equipment manufacturers, too, is key," Darly says. "You used to just go out and buy a piece of equipment, but it doesn't work that way anymore. The equipment has to be designed around the whole system.

  Processors require batter/breading systems that control moisture. During heating, moisture travels from the substrate, through the coating and into the air as steam. This creates several potential problems: it can negatively affect substrate texture and eating qualities; it can lower finished-product yield; and it can change the coating texture or affect its adhesion.

  In addition to the textural issues, processors want to retain as much moisture as possible for economic reasons. On a weight basis, it's much more profitable to sell water than any other ingredient, including oil. Increasing the moisture of the product increases the yield. Yield increases also can be achieved through substrate redesign.

  The obvious answer is to formulate with the film-forming, structure and adhesive ingredients already mentioned. But other factors should be examined. Fish or shellfish, like shrimp, might be coated with an ice glaze for preservation. However, if that ice-coating is still in place prior to coating, the coating will have a very difficult time adhering to the substrate once heat is applied and ice melts.

  Another reason to tie up the moisture is improving freeze/thaw stability. This helps prevent ice-crystal damage and moisture migration from the substrate to the coating. Hydrocolloids also help address this problem.

  The specific processing and reconstitution that a product encounters affects the ingredient selection.

  Mechanical shear on batter can be a negative. It can change the viscosity with ingredients that exhibit shear-thinning. This can alter pick-up. It can damage the starch granules and negatively affect their functionality. This can affect batter viscosity. Shear creates heat and this can affect the leavening system. Shear also causes breakage of the bread crumb.

  The product might be submerged in a batter or breading, or tumbled. A cascade also might be used. This can affect the type and the condition of the coating product.

  A product can be packaged raw. This means the batter will not be set by heat and it will not adhere well until it enters a frozen state. However, most batter and breaded products undergo either a partial or complete cooking process. This can be done with frying, baking or combining the two.

  However, maintaining a high moisture can spell trouble for a designer looking for crispness. Both process and ingredients used can create a moister or even tougher coating than desired.

  When added to the substrate, binders, or marinades that hold onto moisture and fat, help control moisture. Crumb geometry also is a factor. A combination of crumb types, from fine to coarse, can act to absorb any subsequent layers of coating."It's a matter of creating enough physical sites for improved adhesive qualities," Baur says.

  "A larger particle size on the spices used in the outer breading can give some visuals," Kirn says. "Some flavors will flash off during the frying, resulting in a reduction in flavor, or changes in the delivery. One thing you can do is to imbed or design a flavor in a particulate that can carry the flavor through the frying process. It can give you a unique advantage by combining the visuals and a more stable flavor delivery."

  "Although most people put microwave directions on the products, they are willing to accept the fact that microwavability is not as important, and can still accept compromises," Darly says. "The big demand is to go to an ovenable product that has a similar texture to a product that has been fried. That also includes products that have never been in a fryer.

  This doesn't necessarily translate into low- or reduced-fat, but it could. And the less fat and further away from frying, the more difficult it becomes to match that gold standard.

  For products needing to make a claim, it's possible to formulate a coating with low fat levels, combining it with a lean or fat-free substrate. "Sometimes a low level of fat does a lot of good," Braun says. "We like to put a little fat in some of our Newly Crisp(tm) systems and leave it out of others. But, if you take a boneless, skinless chicken breast and you use our ovenable system, that finished product has the flavor, texture and appearance of fried food, but it is actually 94% fat-free."

  The choice of crumb also is important for products not fried, Kirn says. "For a microwavable product, you have to use an ABC or JBC. A flour or a cracker meal would come out much too soft."

  Crumb color can be developed during the bake process. Coloring agents, such as annatto, turmeric or caramel color, may also be added to the crumb formulation.

  Typically, these systems contain some sort of browning agents: carbohydrates that caramelize, or proteins and reducing sugars that undergo the Maillard reaction. These reactions not only produce a darkened color, they also create characteristic flavors.

  "The industry trend is going toward lighter coatings," Kirn says. "You aren't seeing as many processors trying to get 29.9% pick-up. Now they are using 22% or 23%. They are also looking at lighter coatings, rubs and glazes and clear, transparent coatings rather than heavy batter and breaders."

  "These are considered healthful alternatives that are also indulgent," says Braun.

  Eggs, however, are costly. They also can create microbial problems and might have consumer-image problems due to their cholesterol. For these reasons, many manufacturers are looking for alternatives to eggs and egg albumen. To meet these needs, several alternate proteins are used, such as dairy or wheat. Still, while they might impart a brown color and even some moisture-barrier properties, they might not duplicate the characteristic flavor produced by whole egg.

  Somewhere during the development of fry coatings with improved adhesion properties, food scientists realized that many film-formers also inhibit fat uptake. In the days before consumers obsessed about fat in their diets, this was probably no more than a scientific notation, or for someone quick with the calculator, a way to reduce ingredient costs by selling more moisture and less fat. But with the rise in popularity of fat-reduced foods, this characteristic became a valuable tool.

  Kerry's patented Fry Shield( system, for instance, works in conjunction with an outer breader and then a dip solution, Kirn says. A reaction occurs with an ingredient in the breading and one in the outer dip, preventing a certain level of fat pick-up. Other systems have been developed with ingredients that can be added to the batter itself.

  "Not many people have spent a great deal of time trying to model or understand the actual barrier that is created," Conklin says. "However, given what we know, I think that you would find it is somewhat porous, because most of them are leavened. What seems to separate the porous ones that exhibit barrier properties from those that don't would have to be the ingredients that superimpose themselves on that cell structure. They must change the diffusion characteristics of water and oil across that barrier. It's not like a Saran wrap has been laid down."

  In this vein, clear coats for french fries is an area experiencing considerable development activity. This, too, has followed as an extension of the fry-coating technology. Many of the same ingredients promoting batter adhesion and moisture-loss reduction also form rigid films, providing another benefit.

  Other french-fry coatings create a value-added appearance and flavor; these are flour-based batter systems containing seasonings, according to Baur. They might contain crisping-agents and film-formers and low levels of leavening to produce a slight puff.

  Ingredients used for these coatings are food-grade waxes containing rosin or lac (shellac), which is a natural, edible insect-derived product. Waxes and lac coatings use alcohol as a solvent and contain ingredients, such as fatty acids, that act as surfactants and emulsifiers. Or, they may contain amines to dissolve the shellac and rosin, and other ingredients that act as defoamers.

  Many confectionery products require a polish layer, often gum acacia, before applying lac glaze. This can help keep the alcohol contained in the glaze from penetrating into the chocolate, Santos says. Soft candies such as gummies require anti-sticking agents as well as shine, so the waxes manufactured for these applications consist of lac in oil dispersions.

  Other edible coatings, besides confectionery glazes, have been applied to nutmeats. North Dakota State University researchers in Fargo conducted a study showing that coating sunflower seeds with an alginate-calcium lactate film protected them from rancidity and extended shelf life.

  "When you see a very glossy appearance on fruit, especially citrus and apples, at the supermarket, those coating are known as a wax," Santos says. "A wax coating on a whole fruit doesn't necessarily contain wax, like carnuba wax. Wax coatings is a generic term used by the fruit industry. The majority is comprised of shellac or shellac plus rosin, along with defoaming agents in a water-borne dispersion.

  Various ingredients have been used in these applications, including waxes and lac-based coatings, gums such as CMC and HPMC, chitosan, zein, and casein-acetylated monoglycerides. These have been extensively used pre- and post-harvest. Current investigations include testing them on fresh-cut produce to extend shelf life.

  "These inhibit the browning and the deterioration of texture so that you can have sliced apples, put them in refrigerated storage, and take them out in three weeks where they still look and taste fresh-cut," he says.

  Another area, edible packaging films, has been examined experimentally and has resulted in a few commercial applications. Many different materials have been investigated: proteins, starches, gums, cellulose-based products. To date, they've gotten limited use in specialized applications, such as West Haven, CT-based Watson Food's use of hydroxypropyl cellulose films.

  Edible packaging films would have several advantages. They could reduce waste stream on both ends. Not only would they be eaten, or at least biodegradable, they often could be produced from food-processing byproducts, such as surplus citrus pectin or chitin from shellfish waste.

  As food companies seek innovative solutions to their problems, more and more specialized coatings will be developed that make products look better, taste better and last longer.