Browsing by Subject "väärentäminen"

Food adulteration is a constantly growing problem in the quality and safety control of food products. In Finland, the Finnish Customs Laboratory is responsible for the control of imported plant based foods. Among other things, challenging economic situation and gaining economic profit can tempt some people to make adultered products. In a worse case adulteration can cause a serious health risk to the consumer. It’s also misleading when the package doesn’t contain truthful information. Particularly berry jams and purées are easy to adulterate since it’s easy to replace the more expensive ingredient partly with cheaper material, which might be impossible to notice by the sensory characteristics. Strawberry (Fragaria x ananassa) is the most popular and produced berry in Finland. Because fresh strawberry has a short growing season and shelf life, a variety of jams, juices and frozen products are made at home and industrially. Large quantities of strawberry products are also imported into Finland, so there may be some fake products among them. Strawberry contains hundreds of volatile and non-volatile compounds, which are resulted of the plant maturation and metabolism. Some of these compounds are unique to each plant species and also known as marker compounds. The primary objective of this study was to examine the suitability of the selected research techniques for identifying adultered jams by analyzing aroma and phenolic profiles of jams and to develop a preliminary qualitative control method for Customs Laboratory. Techniques used were solid-phase microextraction combined with gas chromatography and mass spectrometry (SPME-GC-MS) to analyse volatile aroma compounds and ultra-high performance liquid chromatography combined with mass spectrometry (UHPLC-MS) for determination of phenolic compounds of self made strawberry jam. Phenolic compounds were extracted by ultrasound assisted extraction prior to UHPLC-MS analysis. Fruits and vegetables used in the jam fraud may be for example apple, pear and pumpkin, so the possible marker compounds were analysed also from jams made of these plants. Self-made fake jams were made by mixing strawberry jam (cultivar Polka) with apple (cv. Ida Red), pear (cv. Conference) and pumpkin (cv. Butternut) jams in proportions of 5–50 % to examine the detection of adulteration. Also some commercial products were analysed to evaluate the suitability of the methods to commercial samples. Results were analyzed and studied by repeatability tests of methods and principal component analysis (PCA). Relative standard deviation (RSD) of the SPME-GC-MS method was considerably higher than RSD of the UHPLC-MS method (51 % compared to 10 %) which tells about weak repeatability of the SPME-GC-MS method. Interesting discovery was the observation of phloridzin from the strawberry samples, since phloridzin has been used as a marker compound of apple although similar observation has been reported earlier. To our knowledge this is the first time phloretin xyloglucoside was also observed from strawberry samples. Self-made strawberry, apple, pear and pumpkin jams differed from each other on the basis of aroma and phenolic compounds composition of the studied cultivars. The aroma profile of apple jam and pumpkin jam differed from each other the most. By the phenolic profile strawberry jam was the most different from the other samples. The mixtures of strawberry jam with apple, pear and pumpkin jams in proportions of 5 %, 10 %, 20 % or 50 % were clearly separated from the self made pure jams on the basis of both aroma composition and phenolic composition. The differences between strawberry jam and fake jams were clear even when the reference jam (apple, pear or pumpkin jam) was removed from the PCA. The 5–20 % fake jam mixtures had only minor differences in aroma and phenolic composition, meaning that determination of quantitative differences with the current methods would be challenging. Mixtures of 50 % stood out the most from other fake mixtures. The evaluation of commercial samples was found to be challenging due to the variability factors of the study. Nevertheless both methods were found to be useful for the detection of adulterated strawberry jams made of selected cultivars. The detection of addition of apple, pear or pumpkin jam was already seen at the addition level of 5 %. With some modification and further development both of these methods can be used as quality control methods at Customs Laboratory.