# MALDI-TOF Mass Spectrometry Applications for Food Fraud Detection
## 2 MALDI Applications
### Other Matrices  
Product quality, authentication, and identification of adulterants are ongoing challenges facing several other food commodities. Hence, other MALDI-based methods have been developed for the detection of different frauds in various matrices. MALDI coupled to capillary zone electrophoresis was successfully exploited [113] to rapidly detect cheap sweeteners (sucrose from cane or beet, starch hydrolyses) in orange juices by monitoring the variation of concentration ratio of low molecular mass saccharides, such as glucose, fructose, and sucrose, and/or the presence of compounds that are absent in the sugar profiles of citrus fruits. Two other proteomic studies were devoted to the assessment of authenticity and traceability of wine. A fast approach proposed [114] the direct tryptic digestion and subsequent MALDI analysis of extracts of white wine produced from different _V. vinifera_ cultivars. The detailed and peculiar peptide profiles present in the relevant mass spectra were converted into simulated images that represented unique \"mass codes\" able to display differences between samples, suggesting their potential use for food quality assessment. The comparison of anthocyanin concentration, main organic acids and sugars, and proteomic profiles of berry with different geographical origin, grape variety, and ripening stage was performed by [PERSON] at al. [115]. In particular, 2-DE combined with MALDI was employed to obtain information about the proteome changes subjecting 128 gel spots to MS analysis, 80 of which were identified as proteins mainly expressed as a response to defense/stress or related to carbohydrate metabolism. A multivariate analysis of protein abundance was able to divide the analyzed samples in different groups according to the considered variables, clearly showing the potential of the approach to provide useful information for wine characterization. Two strategies for the analysis of honey targeting different compounds were successfully developed to differentiate various types of honey and to detect adulterated samples, respectively. [PERSON] and colleagues [116] exploited the molecular weight differences (56 and 59 kDa, respectively) of major proteins of honey produced from different bee species to discriminate between two honey types by 2-DE coupled to MALDI analysis, while [PERSON] at al. [117] targeted oligosaccharides and polysaccharide profiles to reveal adulterations by MALDI MS or MS/MS. Edible insects are available on the European market in ground form, in which any visual identification is impossible, thus causing concrete risks of adulteration that imposes quality and safety controls of such products. A reliable MALDI method [118] was then developed for the detection of proteins in whole insect powder extracts. Species-specific mass spectra were obtained permitting the easy differentiation of the different species under investigation (buffalo worms, mealworms, crickets, and grasshoppers). A further common fraud is represented by truffle counterfeiting, since different varieties are almost impossible to recognize visually, and less expensive species absorb the aroma of higher prized ones when closely stored together. MALDI analysis and clustering permitted [119] to distinguish seven _Tuber_ species confirming misidentifications in 26% of commercial specimens. To the same purpose, MALDI-TOF was applied [120] for the generation of specific mass spectra from 73 truffle tubers belonging to eight different species. Both studies demonstrated the potential of MALDI-TOF to provide useful information for quality assurance and fraud control in the truffle market in a fast, reliable, and inexpensive way. The entire food industry, as well as the field of dietary and sport nutritional supplements, suffers the occurrence of several frauds. _Echinacea_ species (_E. purpurea_ and _E. angustifolia_) are widely used in dietary supplements and their adulteration is a great concern.