Natural RTE Cereal Processing

December 1, 2004

9 Min Read
Natural RTE Cereal Processing

The concept of naturally formulated ready-to-eat (RTE) breakfast cereals is older than you might think: They really got their start in the late 1800s and early 1900s by RTE-cereal pioneers, such as W. K. Kellogg and C. W. Post, both of Battle Creek, MI. The RTE-cereal industry worldwide can trace their roots back to these two individuals.

Both these gentlemen came up with "natural-formulation" RTE breakfast cereals for those who could not eat the standard meat and egg breakfast due to health, dietary concerns or religious views. Post at first developed a coffee alternative called "Postum," a cereal-based beverage. Around the same time, Kellogg was knocking around looking for alternative breakfast foods and stumbled into a method of making corn flakes, one that is still used by Kellogg Company. However, while Post was fiddling around with Postum he couldn't help but notice the success that Kellogg was having, so, he too decided to get into the RTE-cereal biz. By 1920, over a hundred companies in the Battle Creek area made these cereals. Indeed, one could say it was the "Silicon Valley" of RTE breakfast cereals.

These early formulations used by Post and Kellogg were based on natural ingredients. (After all, in those days there were no genetically modified grains and the agriculture industry used no "chemicals.") Many of the processes they used at the start of the RTE-cereal industry are virtually the same as today. Little has changed except for automated control and a strong eye on quality control and assurance. Today, the use of naturally based RTE breakfast cereals is more popular then ever, and it appears that the trend will continue.

If someone talks about cereals in the United Kingdom and most parts of Europe, as well as New Zealand, Australia and South Africa, they're referring to raw, unprocessed cereal grain, such as barley, rye, oats, corn, etc. But in the United States, "cereal" typically means RTE breakfast cereals that fall into the following categories: flaked (Kellogg's Corn Flakes, General Mills Wheaties); gun- or oven-puffed (Kellogg's Honey Smacks); indirect expanded, or 3G or half products (General Mills Cheerios, Kellogg's Froot Loops); direct expanded, or DX (Fruit Rings and Oat Rings sold by Associated Wholesaler Grocers); shredded (Nabisco's Shredded Wheat); granola (Quaker 100% Natural Granola); sheeted (General Mills Cinnamon Toast Crunch); and Weetabix-like bars.

These types of cereal use the same general methods of manufacturing regardless of the formulation -- within reason. However, changes in formulation to produce an all-natural cereal might very well affect the specific process. Most RTE breakfast cereals are made with one of two processes: traditional processes (those discovered by Kellogg and Post) and extrusion-based processes.

Extrusion is a relative newcomer to the RTE breakfast cereal industry. Single-screw extrusion was developed in the 1950s and twin-screw extruders were not developed until the early 1980s. Extrusion processes the material through mixing, pressure and heat generated by the process. Expanded products require a higher pressure and temperature, so that when the product passes through the forming die, the change in atmospheric pressure causes the water in the dough to change to steam, expanding the product and giving it a cellular structure. Pellets for flaking don't require the expanded structure and therefore are extruded at a lower temperature and pressure.

The extrusion process takes the raw material and begins with mixing and conveying to a single- or twin-screw extruder. The product is then conveyed to the next step. A DX product goes through a drier/toaster, to reduce moisture and color the product through browning, then to a cooler, then conveyed to either a coating system, and then to packaging. If the end product is to be flaked, the mix goes to a single-screw former and then is conveyed to a bead-handling system before entering the flaking rolls. The flaked product goes into a drier/toaster, then a coating system and subsequent drier, if used, and then is packaged.

The traditional system can vary quite a bit depending on the type of product made. It includes many, if not all, of the components listed above, as well as: rotary pressurized batch cookers, puffing guns or towers, sheeting rolls, clump breakers and sizing systems, bumping rolls, and temper bins.

Regardless of how they are processed, the final product is nutritionally the same with some minor differences in appearance. Extrusion takes less energy and usually less-expensive raw material than the traditional process, and the original equipment purchase price is less expensive.

The source and type of raw materials may have no effect on the process, or it may affect the process to a degree. For example, with grains, composition differences from crop year to crop year, the region it was grown in, and how it was handled and processed prior to arriving at the cereal manufacturer can all have an effect on the process.

Breakfast cereals made by all of these could be or are naturally formulated. But it should be noted that the heat and pressures associated with all the processes could destroy or degrade color and flavors of many natural ingredients. Though the process temperatures and surface temperatures might be higher, typically the internal temperature will range from the boiling point of water to about 265?F.

All RTE breakfast cereals can be formulated "naturally." But, what in fact is natural? While most of the ingredients used in the formulations of breakfast cereals are altered in some way or another by man, many formulators of natural products avoid certain ingredients. One they avoid would be genetically modified organisms (GMOs). Luckily, cereal-processing equipment doesn't notice whether the grain-based raw materials are GMO or non-GMO and processes both the same. In fact, GMOs often have a leg up in consistency. With other ingredients, however, differences in moisture, or levels of components that provide structure or affect the dough viscosity can provide different, and not necessarily desirable, results.

When it comes to natural, it's hard to escape some debate. For example, is refined white sugar natural? Many people feel "natural" sweeteners should only include things like honey, molasses, rice syrup, barley malt extract and fruit juice. However, not only is sucrose sweeter than honey, giving it more impact on the final products' sweetness level, it's not as sticky as honey. The process "likes" sugar better, because honey-based formulas stick to the equipment and cause problems   (e.g., flakes not releasing from the flaking rolls). Hygroscopic sweeteners, such as honey and fruit juice, can cause soggy products.

You also have to consider the moisture content if you switch from granulated sugar to a natural syrup. If you don't compensate for the moisture, you need to find another way to drive it out. With an extruder, putting a preconditioner before the barrel can increase the moisture content by adding steam or water, but there's little to do to take out much moisture other than change the cooking process. Having a longer, lower-temperature drying process can drive out extra moisture, or moisture held by humectant sweeteners, but that, of course, affects throughput. In an extruded cereal, you can maybe go as high as 7.5% honey in the mix (on a dry basis) before it's difficult to run versus up to about 14% sucrose. Using humectant sweeteners in the coating causes even more problems with coating build-up on the equipment, clumping and sticking in the package.

Everyone considers grains as natural. While removing the bran and germ from wheat and grinding it into flour still results in a "natural" ingredient, many prefer whole grain. The bran will change the nature of the product as will any added fiber. Too much fiber in a formulation can cause the product to have little to no ability to hold together, and it can easily fall apart during processing and post-processing handling and shipping.

Many companies want 13 grams of fiber per 28 gram serving, but levels of 11 to 13 grams make processing questionable. One solution might be to use resistant starch. It's made from a "natural" process, qualifies as fiber, yet in an extruded product, acts just like regular starch.

I had to include purple rice -- it is grown in China and commands a premium price. However, it handles and processes like whole brown-rice flour. The resulting color in the final food product is very distinct and looks as though it had artificial purple food coloring in it. (Just a thought for those avoiding artificial colors.)

Soy products are very popular lately, however the use of these products must be limited because too much soy can make the product hard and have an unpleasant taste. The best solution is to use an isolate -- less soy product, but a higher protein level -- for a high-protein product with a better texture. Using a gun-puffing process might give a better texture versus extrusion as it provides expansion in three directions instead of two.

Moving to a natural oil should be relatively painless from a processing standpoint. Most current cereals use an oil versus a shortening, but you still have to choose one that gives you the right mouthfeel and shelf life.

Adding regular dried fruit, like raisins, can cause problems, also. Raisins are around 18% water and bran flakes have 3%. Moisture moves from the raisins to the flakes and causes the raisin to get hard and the flakes to get soggy. To avoid this, the producer can coat the raisins with moisture-migration barriers, such as oat flour, sugar or vegetable oils.

Natural, whole, GMO or non-GMO, man-made, artificial, refined, milled, sieved, modified, altered, ground, purified, produced by intensive farming, produced naturally, or gleaned in the wild state -- the resulting RTE breakfast cereals all can be processed on similar equipment. Taste, appearance, ingredient cost and processing parameters, however, can be different and noticeable.

Eric Sevatson, member manager, at USC, LLC, Sabetha, KS, has a degree in Milling Science from Kansas State University. He has worked for International Multifoods, ADM, Quaker Oats, Kellogg's and Wenger Manufacturing, and started USC, LLC in 1998 with two partners, Jim and Andy Renyer. The company manufactures food and feed processing equipment and other industrial equipment. For additional information call 785/284-0048 or visit .

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