Seafood, in particular fish are a good source of protein and omega 3 fatty acids. As well these beneficial nutrients, seafood can contain trace amounts of different metals. Heavy metals present in water both naturally and introduced to the water system are absorbed by animals living in that environment. While trace elements are found in most seafood, much higher levels are found in predatory sea animals, due to the cumulative effect of their consumption. Analysis of trace metals is important to remain compliant with different countries food laws.
Wheat is a versatile crop. A range of products can be produce from wheat, such as flour, cereals, pasta, beer, starches and glucose syrups. The range of products place it in high demand and as such also put it in the eyes of regulators. In the case of wheat, trace metals have been identified as a risk and levels have been regulated.
For the analysis of organic materials, near-infrared reflectance spectroscopy or NIRS is one of the most used analytical techniques.
Milk contains fat and protein (as casein and whey). The amount of these macronutrients can vary seasonally and depend on the cow being milked. To combat this variability, producers must standardise the components of the milk to both meet consumer expectations with a consistent product and to adhere to regulation.
Learn how to determine alcohol content in beer
Find out what are the detection limits for chromium using various instrumentation.
Acetaldehyde is often present in wine in low levels. It is present as a metabolite of yeasts, particularly if fermentation conditions aren’t ideal, as a by-product of acetobacter and from the oxidation of ethanol. In wine, it is considered a fault with a sensory threshold of 100-125mg/L. It imparts a cut apple or straw flavour to the wine. In some sherries, however, that same flavour is a known organoleptic characteristic of the beverage, and its production is targeted. Samples can be tested to determine if acetaldehyde is present above sensory threshold levels and suitable for release.
An enzyme assay and spectrophotometry can be used to quantify acetaldehyde in a sample. Acetaldehyde will oxidise in the presence of NAD+ and water to produce acetic acid, NADH + H+. This reaction is catalysed by aldehyde dehydrogenase. To measure the acetaldehyde concentration, the sample is mixed with a known quantity of NAD+ and aldehyde dehydrogenase. A spectrophotometer, which measures the absorbance of light at a particular wavelength is then used. The absorbance of the sample is then measured at 340 nm to determine NADH concentration. The acetaldehyde can then be quantified by determining its stoichiometric ratio to NADH. The test only takes a few minutes to complete analysis.
Find out how a shelf life of food is measured.
Testing the quaity of olive oil
Food safety: pathogen detection in canned food.
Formaldehyde in seafood, analytical analysis and regulations.