Proton NMR measurements are used to examine fruit juice products for various aspects relevant to analysis. Subsequently, mathematical expectation can be defined for every sample. At the same time, the same measurements can be used to quantify a series of important components. Since 2005, Bruker has been analysing authentic fruit juice samples made available by SGF from the major production countries, in differing varieties and from diverse production processes. A reference database has been set up with the resulting values so that samples to be analyzed in future can be classified in groups. Various quality nonconformities can be detected using the combination of chemometric statistics and quantification. Subsequent conventional analyses can then be put to more specific, effective and lower-cost use for confirmation.
In 2007, SGF/IRMA began systematic use of SGF Profiling for testing semi-finished goods for fruit juiced. This had been preceded by a research phase lasting several years conducted by SGF togester with Bruker-Biospin GmbH, providing the technical possibilities and necessary know-how.
In the meantime, SGF Profiling is an important and indispensable part of the analytical control work of IRMA and IQCS.
Profiling is a typical fingerprint method that works particilary on the basis of the representative coverage of fruit juice industry products provided by a joint spectrum database set up by Bruker and SGF. A key role is played in this process by the authentic samples collected by the IRMA auditors, as a comparison spectrum can only be used as an appropriate reference if the samples come form industrially produced juice.
New reference samples ar constantly "fed" into the database to make the resulting statistical models for evaluating juice sprectra more robust and meaningful. The larger and more representative the database, the greater the precision with which the applied mathematical algorithms can detect the parts of the database can detect the parts of the NMR spectra that are characteristic for a certain fruit type, origin or product type, together with those parts of the spectrum that are less suitable for evaluation because of strong natural variations.
While initially SGF Profiling was restricted to just apple and orange products, today all IRMA samples are systematically subjected to the analysis; Meanwhile evaluable models are also available for many further fruits.
The scope of statements made on the specific fruits differs from case to case as the method only uses models that have been validated for the specific fruit type.
In future the mathematical validation of the models as well as the plausibility check will remain a continuous task of Bruker and SGF. Already existing models have to be checked in terms of new fruit growing areas, new fruit varieties, innovative processing technologies or specific effects depending on the production year. Aspects of specific quality problems in the industry have to be considered as well. The number of models and examined fruits will extend on short notice.
Aspects checked by SGF Profiling in one single analysis include in particular authenticity, processing technology and the presence of vitiation indicators. The resulting savings make it possible to focus attention increasingly on controlling food safety (pesticides, heavy metals, mycotoxins).
At present, thanks to the many possible statements that SGF Profiling can generate from one single measurement, in many cases the methos saves costs during analytical tests; on the other hand, SGF Profiling is still to young to act as an official method providing evidence in legal disputes. That is why a conventional reconfirmation is vital in case of complaint. At the moment, the method can be mandated to two commercial laboratories, both of which also give advice. Of course we are also available for questions and support in the framework of our Hotline Services.