Sound check! Confectioners ready mics for acoustic testing

Auditory testing to measure the crunch noise a product will make when it is chewed in the mouth is quickly becoming widespread in the confectionery industry.

Sound is intrinsic to how a consumer experiences crisp and crunchy products and according to Marc Johnson, President, Texture Technologies Corp it is an essential part of the consumer experience.

“I think sound is important for consumers – it’s a very high consumer attribute. They won’t forgive if they bite a Kit Kat bar when it’s supposed to be crisp and it’s not crisp.”

“Sound can be quantified. It’s repeatable and comparable.”

Adding sound to force data

Texture Technologies supplies texture analysis equipment to confectioners in the US and Canada including Nestlé, Mondelez, Mars and Hershey.

The equipment is used at R&D level to test new products and in production areas to ensure lines are meeting agreed quality specifications.

The technology is typically used to measure force variations that can be used to quantify the texture of products, measure shelf life and to demonstrate the weight a product can take in packaging and shipping. But now many more companies are testing sound as well as force.

Smaller plays move for acoustic testing

“The latest innovation is acoustic. It is a few years old but it’s being used more and more,” said Johnson.

He said that larger companies such as Nestlé had been acoustic testing for the past few years, but he said the concept was novel to many smaller players. “The idea is still new to the industry as a whole.”

How it works

Acoustic testing using Texture Technologies equipment requires a regular force-measuring TA.XTPlus Texture Analyzer and a separate Acoustic Envelope Detector, which is much like a microphone.

The instruments work together to capture audio feedback, which is synchronized with force data. A confectionery product is snapped using a knife on the instrument or bended at three different points.

The equipment develops an acoustic profile of the product, which can be used to help R&D teams decide which ingredient combinations work best to get the desired level of crunchiness. A manufacturer may test a rival product to get a reference of the levels required and compare it to his own blend.

The cost of both test instruments will set a manufacturer back around $30k. Manufacturers can choose between a calibrated microphone and a non-calibrated version. The calibrated version gives more accurate measurement, which is unperturbed by vibrations from stormy weather, but it costs around $4k more.

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Acoustic testing can help chewing gum makers develop the perfect coating for an appealing crispiness, says Texture Technologies

Inclusions increase need for sound testing

According to Johnson, acoustic testing is becoming more common for the industry as confectioners increasingly opt for products with inclusions.

“We definitely see a lot more crispy crunchy elements. That’s growing a great deal."

When inclusions are added confectioners must ensure chocolate adheres to the addition, but if it become too adhesive the product can become brittle, which may harm the sound it makes when snapping.

Testing sound levels can help manufacturers choose which inclusion gives the best crispiness or crunch feel.