35 Food & Beverage Analysis
Cryogenic grinding of samples with volatile components
For samples that require cooling during the grinding process, the GM 200 or the larger GM 300 are suitable. Cooling may be necessary when, for example, volatile components like pesticides have to be detected, or when the sample material is soft and elastic and needs to be made brittle to break more easily (Figure 4). This can be done, for example, by mixing the sample with twice the amount of dry ice. Once the mixture is suffi ciently cooled, it is put in the grinding container of the knife mill and homogenised. To release the overpressure, Retsch has designed a special lid with a large opening.
Figure 5: Adapters for 2 ml tubes used in the Mixer Mill MM 500.
the samples up to 100°C during a homogenisation or mixing process. This can be very helpful, for example, if oils need to be mixed to increase viscosity. For such applications, stainless steel jars up to 125 ml size, fi lled, for instance, with 8 x 20 mm steel balls for mixing, are suitable.
Figure 4: fruit gum before and after grinding with dry ice in a knife mill.
If small amounts of several millilitres need to be embrittled and remain cool during grinding, the Retsch CryoMill or the MM 500 control are the best option. These ball mills produce fi ner particle sizes than the knife mills. Sample and grinding balls are placed into the jar which performs horizontal oscillations with a frequency of 30 Hz. The grinding jar is continuously cooled with liquid nitrogen from an autofi ll system before and during grinding, making the sample material hard and brittle so that it can be easily pulverised. This method can even fully homogenise heterogenous samples like chorizo sausages to a fi neness of around 300 µm.
Small volumes, high throughput
In mixer mills like the MM 400, different adapters can be used, allowing for processing of, for example, single grains in 20 x 2 ml single-use tubes or 2 ml steel tubes. The advantage of the steel tubes is that they won’t break even under cryogenic conditions. Larger models like MM 500 nano or MM 500 control accommodate up to 36 x 2 ml single use vials or 18 x 2 ml steel tubes (Figure 5). Thus, mixer mills are perfectly suited for grinding very small sample amounts at high throughput rate, at room temperature but also under cryogenic conditions.
Paste making procedure
Sometimes food samples like chocolate or other sweets need to be warmed to improve, e. g., the viscosity. Retsch’s MM 500 control offers the option to heat
Sample preparation for pesticide analysis with the QuEChERS method
The so-called QuEChERS method (‘Quick, Easy, Cheap, Effective, Rugged, and Safe’) was developed to make sample preparation for pesticide analysis more effi cient. For this method, 10 g of the homogenised food sample is extracted with 10 ml acetonitrile, diluted with a salt mixture, by shaking for 1 to 3 minutes. To simplify the lab work and ensure representative results, the shaking processshould be carried out in a modern lab mill like Retsch’s Mixer Mill MM 400. Up to eight 50 ml Falcon tubes can be placed in an adapter and moved with a frequency of 30 Hz, ensuring thorough mixing and consequently a good extraction. Finally,the organic phase is dried and submitted to chromatographic analysis to detect the pesticides.
Summary
Retsch provides a range of laboratory mills for fast, accurate and neutral to- analysis preparation of virtually any food sample. With a variety of accessories allowing for flexible adaptation to the sample material and volume in question, samples with high water, sugar, oil or fat content as well as granular materials are easily homogenised. Cryogenic grinding with liquid nitrogen or dry ice is suitable to process soft, elastic materials or those with volatile substances. Heating can enhance the mixing effects of sticky samples. With the correct sample preparation process and suitable laboratory mills, the effectiveness and reliability of food analysis can be greatly increased.
Unlocking beer quality with analysis
for nitrosamine control The malting process, a pivotal stage in beer production, introduces a potential hazard with the formation of nitrosamines - carcinogenic compounds that can permeate the final product. Safeguarding consumers and preserving the integrity of your brand necessitate meticulous control of nitrosamine levels.
Ensuring adherence to legal standards is crucial, as consumer safety relies on the quality of the malt. The necessity to assess and regulate nitrosamine content in beer goes beyond a mere legal obligation; it evolves into a fundamental principle of responsible brewing.
External testing can render you feeling powerless, fostering uncertainty about the safety of your products. Ellutia acknowledges the intricacies of nitrosamine analysis and introduces a tailored solution for brewers - the 800 Series TEA (Thermal Energy Analyser). This detector is purposefully crafted for the precise and efficient detection of nitrosamines, bestowing brewers with the authority to regain control over product safety.
Ellutia empowers brewers to reclaim control with the 800 Series TEA. Through scheduling a complimentary 30-minute consultation, they delve into your testing needs, discern what’s effective, and explore avenues for enhancement. From system customisation to training, Ellutia expertly guides you, ensuring the seamless and effective transition of bringing your testing in-house.
More information online:
ilmt.co/PL/lvzx 61782pr@reply-direct.com
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