The IFU Methods of Analysis Commission have completed and published a new recommendation R20, which is available to access for members via the IFU website www.ifu-fruitjuice.com selecting the top menu bar “Methods of Analysis”.
Dimethyl dicarbonate (DMDC, trade name Velcorin®) is used for the cold sterilization of beverages. The use in juices is approved for selected countries such as USA, Mexico, Brazil or Australia and New Zealand. In the EU and according to the Codex Standard the use as a food additive in juices is not listed. DMDC is degraded quickly after application and therefore it is not directly detectable in the finished product. It’s detection can only be carried out indirectly via analysis for its decomposition products which in an aqueous matrix are compounds that may be seen in soft drinks. These components (MeOH & CO2) are only conditionally suitable for a clear detection of its use. In the presence of methanol or ethanol, small amounts of dimethyl carbonate (DMC) or ethyl methyl carbonate (EMC) are also produced. These two compounds can be used as indirect proof of treatment of a product with DMDC. This recommendation reviews the detection method.
Use of polyphenols in the analysis of fruit and vegetable juices and purées
Anthocyanins and flavanone glucosides have been used for years as part of the authenticity assessment of red/black and citrus juices, typically using IFU 71 & 58 respectively. These components comprise only a small selection of the polyphenolic compounds that are available to the analyst for the assessment of juices. The generalised use of polyphenolic compounds as a means of detecting mixtures of juice was developed by Wade’s group at Procter and Gamble in the late 80’s. This procedure works well in juices where there is a reducing environment, such as citrus juices, and produces stable peak profiles. However, in systems with active polyphenol oxidase (PPO) enzymes, such as apple, pear and bananas, some peaks can be lost, due to oxidation and subsequent polymerisation, so these profiles tend to be less stable.
Unlike the chromatograms seen with the anthocyanin procedure, which often only contain a few peaks , traces for the polyphenols are much more complex and generally contain many more peaks. Due to the complex nature of these chromatograms, it is generally impossible to use reference libraries for positive peak identification due to small shifts in retention times between chromatographic runs. This means that control samples should be run with each batch of test samples for comparison purposes unless positive identifications can be made by using more specific detectors, such as diode array (DAD) and/or ideally mass spectrometer (MS), where a positive identification can be made either from an accurate mass measurement or by specific “mother/daughter” transitions.
This recommendation has been published and is available via the IFU website under Methods of Analysis
This recommendation has been revised and is available via the IFU website under Methods of Analysis
General information
Patulin is a mycotoxin produced by particular forms of moulds typically from the genera aspergillus, penicillium and byssochlamys. Patulin is normally found in apples or pears that shows areas of rot but has also been detected in small amounts in other fruits. It can be a significant problem in fruits that are suspectable to “core rot”, e.g. Bramley apples, where the fruit might look quite sound “on the outside” but may actually contain a very high level of contamination with patulin in the centre of the fruit.
Since this recommendation was first published there have been a number of new methods developed to assist in the analysis of patulin, which are discussed in this revised recommendation.
Access to IFU publications
Available to Corporate and Association members and subscribers to all publications by logging onto the website. Individual publications can be purchased via the on line store. Friend members (cat 2) have access to 5 publications per year.
Basic quality systems for juice laboratories
The IFU methods collection holds a comprehensive list of procedures that have been specifically developed and validated for fruit and vegetable juice products. This is not always the case with other methods.
Having the appropriate IFU method is a good start but there are additional challenges to ensure a method is appropriately applied in the laboratory or factory environment.
IFU recommendation number 15 has been published by the Methods of Analysis Commission to assist Laboratory Managers as to the type of checks and controls they should consider adopting to ensure their lab produce reliable data.
It includes topics on:
- Documentation
- Training records
- Servicing / calibration
- Quality Assurance samples
- QA sample analysis and charts
- Performance analysis schemes
- Data management
As a corporate member or subscriber you can download your copy via the website using your log in details @ www.ifu-fruitjuice.com.
