Is Oven Balancing a Challenge for You? In-Process NIR Offers a Solution

While automated in many ways today, food production on an industrial scale still has unexpected variables that can impact quality. When ingredients are received, mixed, formed, put through a cooking process, seasoned, and finally packaged, an imbalance in moisture and fat content can lead to a poor result. This fact is especially true for baked snack foods, where ingredient quality and process control are essential to producing the best products.

Oven balancing is a process control challenge for many producers of baked goods. Many industrial-sized ovens contain multiple overhead heating elements that bake the raw dough in sections. As with all machinery, these elements can begin to run too hot or too cool over time. It is up to the operator to identify these variations and take corrective action to reduce waste and downtime.

Also, a baked or fried snack product’s composition changes as it advances throughout the process. The data acquired during the analysis of raw ingredients or routine grab samples at various stages do not always transfer into production. Suppose a product exits the oven appearing underbaked or possibly burnt. In that case, the operator may erroneously blame their oven settings when it may be that the moisture of the raw dough is out of specification.

Therefore, having a method to monitor moisture and fat content at critical stages in production allows companies to achieve end-to-end control, helping reduce waste, maintain ideal product standards, improve operational efficiency, and manage energy costs. This is achieved with the help of in-process near-infrared (NIR) technology. 

How NIR is Used in Food Production

Laboratory/ At-Line NIR Analyzers

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In-Process NIR Analyzers

At-line NIR analysis has long been used as a fast and effective tool to help food producers analyze their products for important quality constituents. These include moisture and fat, protein, ash content, fiber, sugar, and others; all play a critical role in the process.

Whether used for measuring the quality of incoming ingredients or for the periodic sampling of products before packaging, at-line NIR allows food producers to keep their quality analysis in-house, reducing their reliance on quality lab analysis.

However, for many companies, at-line NIR insights have helped lay the framework for an in-process moisture and fat analysis solution. In-process NIR sensors are effective technologies for close-loop control of ovens, fryers, belt speed, and other processes where moisture or fat content variation occurs. These systems can integrate into existing control systems with industry-standard IO protocols, adding valuable data to maximize production efficiency in most food processing environments.

As this world-renowned snack cracker company discovered, with some creative thinking and application know-how, the NIR calibrations they use to confirm their products at-line gave them a head-start in developing a novel method to control cracker quality before and after baking. 

About the Cracker Producer’s Application

This cracker producer was already familiar with at-line NIR technology – specifically the SpectraStar™ XT Series Analyzer. Routine at-line NIR analysis with the SpectraStar system has been a core step in their quality program for years, especially for analyzing dough samples for moisture and fat content after leaving the mixer and finishing products at the oven exit.

In this process, a dough sheeter presses the cracker dough into a long uniform sheet, then passes it on a conveyor to the oven. The oven has three overhead heating elements designed to bake cracker dough uniformly as it proceeds through the conveyor. Therefore, knowing the cracker dough moisture and fat content before and after the oven is critical to ensure that the oven is balanced and, thus, produce consistent final product quality.

Work Begins with KPM on an In-Process Monitoring Solution

The company agreed to test the MCT460 Series online food-grade analyzer – the MCT466-SF – at one of its largest cracker manufacturing facilities. The sensors were configured for moisture analysis of cracker dough and the moisture and fat in the baked crackers. The units were pre-calibrated at the KPM Analytics applications lab. They made final adjustments onsite using comparison test results from their SpectraStar XT system for both the dough entering the oven and the baked product exiting it.

After several weeks of testing, they discovered considerable downtime savings by controlling the moisture in the dough to within the process specification. When the moisture in the dough fell below the lowest moisture limit, it became sticky. It would not efficiently pass through the rest of the process and, at times, be discarded from production.

In the past, making this adjustment in real time was impossible -- but not anymore, thanks to their solution with the accurate calibration of the MCT466-SF with the SpectraStar. 

Analysis Sequence for Product Entering the Oven

Ultimately, multiple fixed measurement MCT466-SF sensors were used for the dough portion of the process to analyze the entire width of the cracker dough entering the oven. The company worked with KPM Analytics to position sensors at equidistant locations across the raw dough.

Operators were visually alerted to the out-of-specification dough with a Light Stack connected to the team of MCT466-SF analyzers. A "Yellow" light would indicate when the dough was headed towards specification limits giving enough time for the operator to make process change. A "Red" light would tell that the dough hit the lowest moisture specification.

This simple yet effective application provides the operator with valuable information to take corrective action and adjust their dough formulation before risking a production run to waste.

Analysis Sequence for Product Exiting the Oven

The crackers exiting the baking oven required consistent moisture and fat readings to give the cracker its uniform crunch and taste. To their surprise, the moisture content varied from one side of the conveyor belt to the other because of incorrect balancing of the baking oven zones.

As a result, discussions began around a different in-process NIR offering that could continually scan a product over a wide area: The Guardian-HD system.

Initially developed for the web profiling industry, the Guardian-HD features a NIR sensor mounted onto a custom-built traversing frame. These systems provide rugged, non-destructive scanning to monitor moisture and fat content in real-time.

With the ability to scan the entire belt width, the operator was better equipped to determine whether their oven worked to specifications and adjust as needed. The company employed a similar light stack application to their pre-baking moisture and fat control application. 

Once again, the SpectraStar XT was instrumental in streamlining their calibration of Guardian-HD to analyze moisture and fat to their necessary specifications. This gave the customer confidence in their application, leading them to implement similar applications across their other plant locations around the globe.

Control Snack Food Quality Everywhere It Matters

While varying in size, number of production lines, and other details, many baking operations generally follow the same core steps in their production process. As this cracker producer found, in-process NIR instrumentation produces a reliable and repeatable measurement of important quality constituents without disrupting production nor requiring routine maintenance or calibration. For other examples, download our free white paper covering other creative solutions for snack producers to command quality at critical operational stages.