Solving unexpected shelf-life issues in a new soft drink

A leading UK soft drinks manufacturer needed to predict how their recipe would perform when being scaled up. Here's how we supported them.



The challenge


It’s not always easy to predict how a recipe will perform when scaled up - particularly when it comes to stability. So this vital aspect needed to be fully assessed during production trials of the new concepts. RSSL was asked to carry out robust stability studies to confirm that the desired product shelf-life would be achieved.



Our approach


RSSL’s analytical experts designed a shelf-life testing programme according to the formulations and characteristics of the new products. Consideration was given to a number of key factors including pH, Brix and preservative content, as well as the processing conditions and final packaging.

Invest RD 4960 HR


Our multi-disciplinary team monitored the microbiological, chemical and organoleptic requirements of the products throughout the defined shelf-life period using:


  • Real time testing: To mimic consumer handling and conditions of use


  • Accelerated testing: To provide indicative information more quickly. Samples of each product were tested at frequent intervals during shelf-life and beyond, to counter potential irregular reactions due to the modified conditions


Given that the trial samples were fully representative of the final products in terms of processing and packaging, we were confident in the validity of our testing strategy and data generated.

'RSSL’s rigorous shelf-life programme and wider technical expertise proved essential to the success of our NPD project. The team identified the product issue at the crucial scale up stage, ensuring minimal disruption and preventing costly problems further down the line'

Expert problem solving


During initial organoleptic evaluation of the soft drink concepts, our experienced assessors noted that one of the products was slightly hazy compared to kitchen-scale sample. At the same time, our post-production microbiological testing found that this product developed an oil ring on the surface that was just visible on the bottle neck after one week.


Having identified this as a potential formulation issue, our product development and microscopy teams used a number of analytical techniques to establish the cause.


Experience told us that one or more of the flavours were most likely responsible for the problem. Based on this theory, we carried out qualitative assessments at bench scale to screen each flavour in the base formulation.


We also conducted separate analysis of the unwanted oily layer using a light microscope. It showed that the droplets contained a flavour carrier that was present in one of the flavours used in the product. Further FT-IR analysis (Fourier Transform Infrared spectroscopy) indicated that the flavour components were more prominent in the oily layer than the main body of the drink and - crucially - one particular flavour was contributing to the ringing effect. These findings confirmed those of the qualitative assessments.



The result


With the problem flavour identified, we could then confidently revisit and optimise the product formulation at kitchen-scale. Using our extensive technical expertise, we worked closely with the flavour supplier to reduce the non-soluble components within the flavour itself. This allowed us to achieve the required shelf-life stability, without compromising the all-important flavour characteristics of the final product. This success meant we could then scale-up the variant and validate its shelf-life through further storage studies alongside the rest of the range.

Discover how RSSL can support your shelf life studies

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