One of the qualities of a good candy cane is its brittleness: not being bendy, tough and chewy. You can tell a good candy cane apart, by breaking it in your hands. But how brittle is how good, and where and how does it break? When is a candy cane past its best? Or will it break during packaging and transport—and can you manufacture a better product to a more consistent formula? It’s all a bit subjective, so how can you translate an expert opinion on a good day into something more objective?
Here we explain how an expert subjective opinion can be correlated with objective data for accurate and repeatable testing. When done at the point of production, this kind of testing can save time and money and guarantee product quality.
A Food Technology Corporation (FTC) TMS-Pro texture analyzer was fitted with a 500 N intelligent loadcell and a lightweight three-point bend fixture. By placing a candy cane across the two lower supports, the upper anvil could be brought down onto the center to bend it evenly. Freshly unwrapped candy canes from the same box were tested by bending to their break point, and the force required measured accurately.
The program controlling the texture analyzer maintained a speed of 250 mm/min, first to just touch the surface, then proceed to a distance of 15 mm. This was judged sufficient to break a brittle sample, after which the machine returned to its starting position. At the end of each test the software calculated the peak force encountered in the break, but also produced a graphical trace of the process of breaking. The samples could then be compared in detail.
The graphical representation from TL-Pro, of the test results for the four samples, is shown here (force applied, against cumulative displacement).
The samples are all very similar, showing no signs of going soft and flexible. The break is sharp, at a consistent bending displacement, but sample 3 stands out with a higher peak force. The same results with additional calculations are shown here.
Brittleness can be seen in detail by using a texture analyzer, and samples regarded as good will give a narrow range of breaking forces and a consistent pattern. Variables that need to be taken into account include temperature and humidity, so these need to be quoted against test acceptability values. Under these conditions, the test data can be used as a base line against which production lines or product reformulations can be tested. They can also be used to test that packaging is suitable for intended shelf life.
The added value of mechanical testing is that not just the brittle strength, but the manner of break (often somewhat unpredictable) can be assessed and improved. Different heating and cooling times, the effect of different colorings or stick diameter can all be compared with a baseline product, for example.