When it comes to the crunch

Textural challenge

In all foods, for humans or animals, texture is a fundamental aspect of the eating experience and can make the difference between a product that vanishes in seconds or is rejected at the first mouthful. As it is influenced by so many factors, including ingredients, processing parameters, packaging and storage conditions, texture is notoriously difficult to perfect. But getting it right ensures food is enjoyed, nutrients are consumed and brand loyalty is maintained.

Despite being a cornerstone of pets’ diets for many years, kibble remains a textural challenge for many manufacturers, not least because of its changing contents as more and more consumers seek pet food that is more similar to their own diet – gluten-free, low salt and added vitamins varieties are all in demand. Instrument-based texture analysis is a fast, accurate and repeatable methodology for assessing, and therefore perfecting, kibble texture. Several tests can be performed with the TA.XTplus texture analyser from Stable Micro Systems.

Durability (hardness) and brittleness

Balancing the need for a satisfying crunch and ease of biting is challenging. Pellet hardness can be measured using a cylinder probe. The texture analyser measures the force required to compress the sample; the higher the force, the more durable the kibble. More useful results can be achieved by performing a bulk test with a compression platen, which creates an averaging effect. Both these tests also give an indication of brittleness, which is defined as the number of peaks created during the compression process. Each peak denotes a fracture event and therefore quantifies brittleness.

Acoustic emission and video playback

Where compression tests give a clear graphical indication of kibble’s hardness, many manufacturers are supplementing this data with audio and video recordings of the texture analysis test. This information can be synchronised with the force data and played back frame-by-frame to observe and hear the fracturing of the pellets, which happens too quickly to be understood by the human eye.

Compressibility

With many pet owners pre-soaking kibble before offering it to their animals, it can be easy to use too much fluid or leave the food too long in it, resulting in an unattractive mush. Using an Ottawa Shear cell, which securely contains both the pellets and the fluid during testing, manufacturers can define the ideal fluid volume and soaking time to give guidance to their customers.