How NIR is Used in the Snack Food Industry

Near infrared technology (NIR) has historically been used in the snack food industry for measuring moisture and oil, the two most critical constituents for controlling a snack food process. In addition to measuring moisture and oil in raw ingredients, in-process products and finished snacks, the Unity® Scientific™ SpectraStar™ XT can measure the seasoning content that has been applied to the chips.  

Added seasoning is the costliest part of the snack manufacturing process. For example, adding 1–2% more than the target seasoning amount will add thousands of dollars per week to manufacturing costs. Under- or over-seasoning of product will lead to customer complaints and eventual loss of market share.  

Seasoning measurement in a snack plant varies widely. Some manufactures do not measure at all because they trust their application hardware to work correctly. This is very dangerous, as applicators often get clogged or fail. Furthermore, simply calculating how much seasoning is used based on how many pounds of chips are produced does not accurately reflect the amount of seasoning applied to the chips.  

Other tests used for seasoning measurement are:

• Color measurement – The concept is that the darker the product, the more seasoning is applied. This could be quantified by a color meter. The drawback here is that some seasonings are clear and cannot be measured by a typical color meter.
• Salt Measurement – In many cases, the salt in a snack product is added in the seasoning. If the amount of salt in a seasoning lot is known, it is easy to calculate how much seasoning is applied to the product if the salt in the seasoned chips is measured. The typical salt test is a titration ranging from a very simple, operator-driven test to an automated instrument with an auto-sampler.  

Simple salt titrations are very subjective and vary widely from operator to operator. This causes issues with accuracy. All titrations use Silver Nitrate in the method. The chemicals used in the test are expensive, and disposal of silver nitrate is expensive as well. Furthermore, titrations take approximately 5–15 minutes per sample.  

A rapid method for analyzing seasoning accurately and quickly is needed in the snack food industry.  

Use of the Unity® Scientific SpectraStar™ XT NIR Analyzer for Seasoning Analysis

The Unity® Scientific SpectraStar™ NIR system can measure seasoning content in less than 30 seconds with no expensive chemicals. This allows the plant to control their seasoning application to better than 1%. With this amount of saved seasoning, the instrument can be paid for in a matter of months.  

Calibrations

The SpectraStar™ XT is calibrated by running a set of known samples that are used to train the instrument. Calibrations are developed on each seasoning. Since every company makes unique products, calibrations developed for Company A will not work for Company B. However, a calibration developed for Company A will work on the same product made at multiple Company A locations.

For the lab method, we will use either the titration method as the reference for calibration or a set of samples will be made up by weight. In the latter method, a set of standards are created by weighing out a certain amount of seasoning and a certain amount of base chips. The sample is then ground in a food processor.  

The calibration method used will depend on the current method employed by the factory. The goal is to include as much variation (different production days, different seasoning lots) as possible into the calibration to make it more robust.  

Samples should be ground using a food processor. The grinder must have a bowl big enough to grind 200g of sample. As consistent particle size is critical to accurate analysis, it is recommended that a timer be used to control the grinder.  

For routine measurement, an error of around 0.5% or better is expected. Below is an example of a BBQ seasoning on potato chips:

Salt & Vinegar seasoning on potato chips:

Conclusion

The Unity® Scientific SpectraStar™ XT NIR Analyzers offer a rapid measurement method that can analyze a sample for seasoning content in less than 30 seconds using no chemicals. The accuracy and reliability of the SpectraStar™ allow it to be used as a process control tool for seasoning content. This will provide a quick payback for the plant and additional savings going forward in both costs and energy.