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To comply with regulations, juice and soft-drink producers must monitor the concentration of sugar in their initial concentrates and final products. This is typically performed via Brix determination – a simple yet accurate analytical technique which by definition measures the concentration of 1 g of sucrose in 100 g of aqueous solution.
Rugged, reliable instruments are crucial to efficient quality control, especially near-line. METTLER TOLEDO offers simple and affordable new temperature-controlled refractometers, also known as Brix meters; this EasyPlus™ refractometer series comprises three compact and robust benchtop meters, the Easy Brix, Easy R40 and the Easy Bev, a vertical model. All are designed to accurately and automatically analyze different types of samples.
Sample measurement
For most beverage types, a small amount of sample is inserted into the instrument and Brix is measured directly. However, for juices not from concentrate or nectars, an intermediate step of filtering out the pulp is required; for carbonated soft drinks, sample preparation involves an additional degassing step.
These complications can be avoided by using the Easy Bev (Figure 1). This model's vertical measuring cell and funnel allow sampling directly from the bottle, preventing pulp from sedimenting within the measuring cell itself. With the Easy Bev, users need only pour out the sample and press start. After measurements are completed there is no need to clean the measuring cell: simply pour the next sample to flush out the previous. This simple, convenient workflow is especially suited to near–production line applications, requiring minimal user training and know-how in Brix measurements.
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Figure 1. Sample preparation steps such as filtering and degassing can be avoided with the Easy Bev. |
A study conducted by METTLER TOLEDO specialists used an Easy Bev refractometer to measure samples of cola, lemon and orange soda, and indian tonic water containing CO2 in two different conditions, degassed and non-degassed.
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Figure 2. ºBrix results and standard deviation comparison for the beverages analyzed. Results reflect 7 replicates for each sample. |
In either case, repeatability of measurements was good, as indicated by the low standard deviation (Figure 2); moreover, the difference in results between degassed and non-degassed samples falls within the limit of error of the instrument, of 0.07% w/w. This confirms that the Easy Bev is an accurate solution to check the quality of carbonated beverages, without sample preparation, on the factory floor.
