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| Kroger's Clackamas bakery plant has six production lines that manufacture bread, buns, bagels, English muffins, cakes, donuts and cake-muffin type products. |
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| Mike Adams, quality assurance manager for Kroger's Clackamas, Ore., plant, improved product quality with a combination of enzymes and process controls. |
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| This profiler is shown in an open thermal barrier. This barrier is closed during processing to protect the profiler from high oven temperatures. |
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| By inserting thermocouples into dough, bakers can obtain a complete process window. Bakers also can place thermocouples on a tunnel oven's belt to measure temperature variations across the width of the oven. |
The baking industry is no longer a 10,000 loaves per hour white bread world. Bakers must give consumers a wide variety of products, all with superior flavor and ideal texture. This variety of products requires bakers to experiment with cutting-edge ingredients such as enzymes.
Modern enzyme blends are used for softness, flavor, to help set structures, to break set structures and to enhance shelf life. Advancements in enzyme technology have mirrored the growing and varied bread market. For every new premium or lowcarbohydrate bread that is launched, a new enzyme technology is developedto accommodate these specialtyproducts' special needs. And, these new enzyme technologies are not only affecting how bakery foods look and taste, but they also are affecting the way bakery foods bake.
"Amylase Enzymes from different sources exhibit varying thermo-stability in the baking process," says Mike Adams, quality assurance manager for Kroger's bakery plant in Clackamas, Ore. "Most E.S.L. (extended shelf life) enzymes are blends of amylase enzymes. All have different temperature ranges and contribute to the crumb character during different stages of the baking cycle."
For example, Adams says that fungal amylase enzymes are readily deactivated at temperatures above 150°F, whereas cereal derived amylase enzymes begin to deactivate at temperatures of 175°F to 185°F. Bacterial enzymes exhibit high thermo-stability and begin deactivation at temperatures exceeding 185°F. "These last the longest and provide extended dextrinization during the gelatinization stage of the baking process," Adams says. "Some may still have minor activity after reaching the typical 200°F to 202°F bread bake temperature."
For every new premium or low-carbohydrate bread that is launched, a new enzyme technology is developed to accommodate these specialty products' special needs.
The effects of enzyme supplementation are not fully realized until about the fourth day after baking, when the reduced rate of crumb firming or starch retrogression can be evaluated.
150% longer
Learning how enzymes affect the baking process can be a headacheinducing job, especially if a bakery is employing new technology across a broad spectrum of products. Kroger's Clackamas bakery runs six production lines for bread, buns, bagels, English muffins, cakes, donuts and cake-muffin type products. In the last five years, Kroger has increased the shelf life of its yeast-based bakery foods by 150% by using enzyme technology, process control, daily monitoring of ingredients and internal product profiling. Similar efforts are ongoing in the company's donut and cake product areas.
"We use enzymes that allow dextrinization to occur at desired baking stages and temperature ranges. This affects the moisture content of the crumb," Adams says. "With a bagel we want a softer, more chewy, moist crumb texture. Therefore, we'll use an enzyme blend that allows enzymatic dextrinization to occur for a slightly longer period at higher temperatures than in bread. For bread, we don't want an overly moist crumb texture so we'll use a different enzyme quantity and blend, specifically a higher bacterial enzyme count," Adams explains.
Understanding how to work with these ingredients requires a fresh approach to process control. Hand held temperature instruments and visual examination are not enough. A loaf of bread can come out of an oven with beautiful color, but when it gets to the slicer, the blades may jam because it's still doughy on the inside.
"When we first started using enzymes at the Clackamas Bakery Plant we didn't completely understand their full range of effects and attributes. This translated into some less than desirable results during testing," Adams says.
Trouble shooting
When a baker adds an enzyme and the result is a bad product, the enzyme usually receives the blame. However, one leading supplier of enzymes says that other than overdosing, enzymes are unlikely to cause these issues and strongly recommends a full baking process review to trouble shoot poor performance.
To better serve customers, one enzyme supplier added system optimization as a technical service to its customer service package. Researching other industries, the enzyme supplier found a technology used in electronic manufacturing that could easily adapt to baking—product profiling.
"Traditionally, bakers have used hand held thermometer systems to measure temperatures at different stages of baking," the enzyme supplier says. "They measure sponge temperatures, dough temperatures and the temperatures out of the oven."
However, new bread formulas for products such as premium and lowcarbohydrate breads require ovens to bake high-mass doughs. And, one enzyme supplier says that most ovens are ill equipped to accomplish this unless a baker slows down a production line. "The answer is to refocus on the internal—product and oven—and get a better balance of air velocity and heat. The need for a tight process window is the key to baking a perfect product, regardless of ingredients."
Process window
A process window is where all thermal variables are synchronized. In electronics, it is the point when solder melts to form the perfect electrical connections between components. In baking, it is the bake time in the oven where bread reaches the optimum temperature to create ideal height, texture, color and to deactivate any enzymes in the recipe.
To determine the ideal process window for bakery foods, one enzyme supplier has borrowed thermo profiler technology most commonly used in the electronic industry. This small data logger has six thermocouple channels that easily adapt from monitoring a printed circuit board to monitoring trays of buns and bread. By inserting thermocouples into the dough and strategically placing others along the oven conveyor, the thermo profiler can simultaneously measure both internal product and oven air temperatures.
This breakthrough idea in process controls caused one enzyme supplier to take the thermo profiler to its enzyme customers to make sure that ovens were functioning within correct parameters. By monitoring both process and product, the supplier was able to show bakers their internal oven heat transfer curve dynamically.
Putting a thermometer in a loaf exiting an oven may show the bread has reached 200°F, but it will not indicate when it reached that temperature. Collecting full temperature information allows bakers to adjust formulas to minimize cost and optimize the process.
"A real window into the process is more than simply running a data logger through an oven. It's a combination of thermocouples inserted into the dough and air temperatures across the oven tunnel that tell the real picture," says a supplier of thermo profilers. "You have to measure conductive heat and convective heat—in the dough and in the oven at the same time."
"I believe that it is impossible to use cuttingedge enzyme technology without very good process control."
Monitoring parameters are entered into the profiling program and the thermocouples are placed across the oven and inside the product. The baker enters the time rate for data collection, the rate the oven moves and the length of the oven. The profiler interfaces to the software and generates a color 3-D profile on a computer screen, showing exactly how, where and when temperature changes occur both inside the product and throughout the full length of oven; longitudinally and in balance, left to right.
Product profiling allows bakers to confirm that the internal temperature of the bread reached a target within a given temperature window. If anything goes wrong, there is a picture of the process that shows where to look to solve the problem, whether a specific area of the oven or in the product.
Each oven is unique, and that can be shown graphically and then balanced to specific product needs. Process monitoring shows what is going on inside the oven. Product profiling shows what is going on inside the product. Together, they provide a window for total process optimization.
Profiling in use
Thermo profiling demonstrations by enzyme suppliers have caused many baking companies to obtain their own profilers. Kroger now uses a thermal profiler to optimize its baking process. The company does not use the tool on every baking run, but it does run the profiler for product oven set up, to evaluate ovens after maintenance and when testing new product formulas.
Adams monitors all significant steps including pH levels, dough temperature, proof time and internal prebake temperatures. His products enter the oven with a 94°F internal temperature. Proper oven operation and settings, verified through profiling, take it from there.
"On a typical test I will first use all six profiler channels to check the air temperature on the left side, right side and the center of the oven. Then I'll insert three thermocouples into the center of the product," says Adams. "As my profiler passes through the oven bake cycle, it's recording temperatures every two seconds and shows graphically if I'm getting the thorough bake out required to deactivate the enzymes.
Because Kroger bakes so many different types of products, it's essential for the company to have complete process control to accommodate the different sizes of product, different weights and different pan densities. "Dough-to-pan volume ratios are important when developing new products," Adams says. "Profiling also allows me to determine the best overall dough-weight ratio to pan volume for a perfect baking cycle."
Profiling expanded
Based on input from users like Mike Adams, one thermo profiler has evolved its system to cater specifically to bakers' needs. Baking has, and always will be, an art. Modern technology is simply adding scientific dimensions to enhance and expand the horizons of that art form.
"I believe that it is impossible to use cutting-edge enzyme technology without very good process control," Adams says. "Before a baker even thinks of implementing new enzymes into his product, he'd better have all process controls in check. If not, he will never know what went wrong if the product is disappointing."
The American Institute of Baking now offers a class in profiling for bakers. This is a sign of the changing times. Baking is not a high-profit margin industry, and increasing oven capabilities through optimization of both the process and product, lowers overall cost. Product profiling gave Kroger a monthly savings of $13,000 in reduced waste on just one line. That is a lot of profit to add to any baker's bottom line at the end of a year. Also, Adams reports that customer satisfaction is at an all time high, which reflects the quality of the products. It's baking as it should be; satisfying as an art and profitable as a business.