How to measure and analyse the texture of food, cosmetics, pharmaceuticals and adhesives.

Tuesday, 14 March 2017

Adding Texture to Tea

The best discoveries are total accidents, and bubble tea is no exception. 

The drink as we know it today found its origins in Taiwan in 1988 when Lin Hsiu Hui, a product developer in a tea house, decided on a whim to pour her tapioca pudding into her iced tea. 

Perhaps excited by the extra level of texture she had incorporated into her drink, she passed it around the meeting room and it was met with acclaim; the product was tweaked and brought onto the market, and its sales rocketed. 

In the years since, the craze has swept Asia, the US and Europe, and found itself in London five years ago. A bubble tea café can be found in most major towns in the UK and the trend is expected to keep rising.

In its current form, bubble tea is a cold flavoured sweet tea containing either chewy tapioca pearls or agar gel balls (aka ‘boba’) filled with fruit juice that pop when bitten, reminding the consumer of the satisfaction of popping bubble wrap. From a texture point of view, its popularity is down to the novelty of incorporating a chewy or popping component to an ordinary drink. 

From the perspective of flavour, the extra excitement from ‘popping boba’ comes from encapsulating a new flavour into the popping bubbles for a surprise when they are bitten; ordinarily a second flavour in a drink will be due to fruit pieces or flavoured ice cubes, both of which infuse the flavour in a less distinct way. Tapioca pearls will release their flavour over a longer time period due to their soft, chewy texture.

What makes a pop-ular boba?

For customers to keep coming back for more popping boba, the brand quality must be consistent. But more importantly, the bubbles must serve as an exciting new texture that surprises the consumer the first time they bite one and provide anticipation each time they come back for more.

For a dramatic pop, a high force and low strain at the breaking point are ideal. The graph below shows an excellent force, but the breaking strain is a little high at 65%. This particular sample does feel too soft and squishy when bitten.

A bubble that is under low pressure will have flexible walls, feeling ‘softer’, and your teeth will have to move a long way to pop the bubble, which will be less sudden and less dramatic. 

A high pressure of fruit juice inside the bubble will provide the low strain and will also put up resistance to the teeth as the pressure will be higher. 

Thicker bubble walls will increase the force, but then the customer is left with a thick agar shell in their mouth, which is not a pleasant sensation. Additionally, the breaking force needs to be high enough that they survive the journey from factory to street stand.

Taking a video of the bubble as it pops can help with quality control. The screenshot below was taken just as the force was decreasing, when the juice squirted out from a rupture at the side of the bubble.

A bubble that splats quickly, projecting a high volume of fruit juice a long way, will be the most exciting in the eyes of the customer.

What’s more, testing efficiency can be increased by doing this type of product testing on an Automated Linear Indexing System (ALIS) for quicker sample throughput.

We can design and manufacture probes or fixtures for the TA.XTplus texture analyser that are bespoke to your sample and its specific measurement.

Once your measurement is performed, our expertise in its graphical interpretation is unparalleled. Not only can we develop the most suitable and accurate method for the testing of your sample, but we can also prepare analysis procedures that obtain the desired parameters from your curve and drop them into a spreadsheet or report designed around your requirements.

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

TA.XTplus texture analyser with bloom jar The
TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

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Watch our video about texture analysis Replicating Consumer Preferences
 Texture Analysis applications

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