Electronic Noses and Tongues: Applications for the Food and Pharmaceutical Industries

The electronic nose (e-nose) is designed to crudely mimic the mammalian nose in that most contain sensors that non-selectively interact with odor molecules to produce some sort of signal that is then sent to a computer that uses multivariate statistics to determine patterns in the data. This pattern recognition is used to determine that one sample is similar or different from another based on headspace volatiles. There are different types of e-nose sensors including organic polymers, metal oxides, quartz crystal microbalance and even gas-chromatography (GC) or combined with mass spectroscopy (MS) can be used in a non-selective manner using chemical mass or patterns from a short GC column as an e-nose or “Z” nose. The electronic tongue reacts similarly to non-volatile compounds in a liquid. This review will concentrate on applications of e-nose and e-tongue technology for edible products and pharmaceutical uses

Following cocoa beans to chocolate : The search for intrinsic characteristics

The assessment of cocoa’s natural characteristics can be used to link cocoa beans and chocolate. Establishing a link between the raw material and the finished product is complicated not only because of complex characteristics of the supply chain but also because of the technology involved in the production and the composition of the ingredients. One may wonder why a link between raw material and the finished product is relevant. Nowadays, more and more attention is given to sustainability, pushing the cocoa manufacturers to take into account social, economic and environmental issues while producing. As a consequence, the demand in cocoa-importing countries for certified sustainable cocoa has increased considerably and is expected to show continuous growth over the next years. Moreover, more consumers have become increasingly aware of the existence of different cocoa varieties and their origins, and the market of specialty chocolates such as chocolates with single-origin bean, organic and fair-trade chocolate has largely grown in the last decades. The aforementioned trends in the chocolate sector and the growing concerns regarding food quality and safety led to a growing effort in the implementation of traceability systems. This trend has facilitated the need to verify and guarantee the origin of the cocoa beans along with the cocoa-chocolate supply chain and to establish a link between raw material and the finished product. For these reasons, the main objective of this thesis is to discover cocoa beans’ traits in terms of the botanical and geographical origin carried along the cocoa–chocolate supply chain. Compositional characteristics of botanical and geographical origin of cocoa beans after fermentation and drying, after manufacturing chocolate and during chocolate consumption were analysed. This information can be used to derive a link between raw material and the finished product, which in turn can be used to support traceability systems. To investigate the cocoa-chocolate botanical and geographical origin information, markers related to intrinsic properties were used: volatile and non-volatile characteristics. The latter include small non-volatile compounds, elemental composition, isotope ratios and hyperspectral profiles. The reflectance of the cocoa beans origin along the supply chain is investigated starting from the consumer perspective with the analysis of the nosespace (NS) profile of consumers eating chocolates manufactured from beans of different origins. Moving back along the supply chain, the possibility to extract botanical and geographical traits from both volatile and non-volatile profiles is further tested in chocolates available in the supermarket. To extract more information cocoa beans and corresponding chocolates to extract raw material markers in a finished product analysing their volatile, elemental and isotopic compositional traits. Finally, the raw material analysis completes the assessment of cocoa beans origin traits along the supply chain. Regarding the botanical traits carried along the supply chain, the volatile intrinsic characteristic showed the potential to track and trace raw material origin along the entire supply chain. It was possible to identify typical volatile compounds of the raw material in chocolate bar and chocolate during chocolate consumption. VOCs were found to be the most robust markers that were carried from cocoa beans to consumer products, revealing a constant shift/change between the raw materials and the finished products. Potential markers (i.e. acetic acid) were detected to reveal botanical traits from raw material to chocolate to chocolate consumption. However, in general, it was difficult to identify specific individual markers carried along the supply chain highlighting the fact that the botanical traits are more related to a general volatile pattern. The same is valid for the small non-volatile compounds analysed in chocolate. Interestingly, when analysing the non-volatile compositional traits, the botanical trend explained the samples overlapping according to the geographical origin. This occurred despite the impact of the processing step or the ingredient added on the origin expression. The brand influence was confirmed also when the elemental and stable isotope fingerprints of cocoa beans and chocolates were compared. Stable isotope signatures appear less sufficient for tracing the characteristics of cocoa in chocolate products without previously estimating the isotope signature of all the ingredients reducing the possibility to use them as origin markers. Our results support the botanical traits’ influence as highlighted for the volatile and non-volatile profiles of chocolate and the volatile NS profile of chocolate during consumption and it indicates that intrinsic features of the beans are retained after processing and even during consumption. Regarding the geographical origin traits carried along the supply chain, volatile compounds reflected the geographical trait from cocoa beans to consumers. Within the non-volatile compositional traits Cr, Fe and Cd appeared to be distinct geographical markers although they are susceptible to environmental contamination. However, along the supply chain, the geographical traits were hidden by other factors. During chocolate consumption, geographical discrimination was possible only within each botanical group. In chocolate, the geographical information was evidently contained by the volatile compounds. However, we highlighted an interference with botanical and brand traits. This was particularly clear when analysing the small non-volatile compounds. Only when reducing the influence of the brands, it becomes clear that the samples are spread according to the three origins. Regarding the raw material, the impact of the geographical origin on the volatile and hyperspectral profile of cocoa beans is influenced by the variability related to differences in fermentation and drying within a country and between countries. Despite these interferences, a similar trend both in cocoa beans and in chocolates is visible for certain compounds, making them usable as cocoa-chocolate linking markers. The evidence from this study suggests that volatile and non-volatile compositional traits of cocoa and cocoa products can be used to verify and/or follow origin traits along the supply chain and link raw material and the finished product. However, more research is needed on how to reduce botanical and geographical interaction and improve the product characterisation along the supply chain. Within the compositional traits that were measured, the volatile profile is the most suitable for gathering information at the beginning of the production and at different stages in the supply chain

Aroma Characteristics of various 'true' and 'false' peppers from around the globe.

The headspace from a number of ‘True’ and ‘False’ peppers was sampled using two different techniques and analysed using gas chromatography mass-spectrometry (GC-MS). Initially, Solid Phase Microextraction (SPME) was tested as a means of sampling freshly released aroma compounds. However, due to poor chromatographic separation the results remained largely inconclusive. The use of thermal desorption dynamic headspace (TD-DHS) sampling proved more successful. Using this technique, over 130 compounds were identified across the 19 pepper samples. The method proved to be effective in sampling volatiles in a way that replicated the consumer pepper experience and allowed for the quantitative comparison of volatile constituents across samples. A number of peppers, with freshly released aroma volatiles previously not described were successfully characterised, including Voatsiperifery pepper (Piper borboneense) and Tasmanian Pepper (Tasmannia lanceolata). The TD-DHS GC-MS method developed was also used to assess the effects of pre-grinding on the volatile constituents of Tasmanian Pepper berry and leaf. Both leaf and berry volatile levels were dramatically reduced due to the industrial pre-grinding processing. Essential oils from Tasmanian Pepper berry (both dried and freeze-dried) and crushed leaf were extracted and analysed using GC-MS. The volatiles identified were consistent with those in the published literature

Expression of multidisciplinary flavour science : proceedings of the 12th Weurman Symposium

The 12th Weurman Flavour Research Symposium contributed 177 lectures and posters to the wealth of flavor knowledge; these were presented in eight sessions: biology, retention and release, psychophysics, quality, thermal generation, bioflavors, impact molecules, and analytics. Emerging topics were discussed in three workshops dealing with flavor and health, in vivo flavor research, and flavor metabolomics. It has been an excellent forum for passionate exchange of recent results obtained in traditional and emerging fields of flavor research. The symposium allowed coverage of the broad diversity of flavor-related topics: comprising odor and taste; applying targeted and holistic approaches; using sensorial, chemical, biological, physical, and chemometric techniques; as well as considering nutrition and health aspects

Expression of multidisciplinary flavour science : proceedings of the 12th Weurman Symposium

The 12th Weurman Flavour Research Symposium contributed 177 lectures and posters to the wealth of flavor knowledge; these were presented in eight sessions: biology, retention and release, psychophysics, quality, thermal generation, bioflavors, impact molecules, and analytics. Emerging topics were discussed in three workshops dealing with flavor and health, in vivo flavor research, and flavor metabolomics. It has been an excellent forum for passionate exchange of recent results obtained in traditional and emerging fields of flavor research. The symposium allowed coverage of the broad diversity of flavor-related topics: comprising odor and taste; applying targeted and holistic approaches; using sensorial, chemical, biological, physical, and chemometric techniques; as well as considering nutrition and health aspects

Impact of enzymatically generated peptides on the formation of alkylpyrazines in Maillard model systems and baked food products

The Maillard reaction is the major route for thermal generation of flavor; it is a very complex cascade of interdependent chemical reactions that has been the topic of many research papers since it was first identified by Louis Camille Maillard in 1912. The aromas in most thermally processed foods, such as bread, cereal products, roasted peanuts, and roasted coffee, are largely due to the Maillard reaction. Currently, more than 2500 different flavor compounds have been identified. Among these Maillard–type flavors, heterocyclic compounds with desirable aromas and low odor thresholds make the most significant contribution. Pyrazines are specific Maillard reaction products known to contribute to the unique roasted, nutty, meaty, earthy, popcorn-like aroma of many heated foods. The generation of pyrazines has been studied extensively in model systems between free amino acids and sugars and studied less in more complex model systems. Nevertheless, in general, food products are known to contain small amounts of free amino acids. Therefore, the main goal of the research was to study the formation of pyrazines in different Maillard model systems containing peptides, proteins, amino acids, and glucose in a variety of conditions that can be related or applied in the food industry. The generation of pyrazines and their formation mechanisms were studied in several model systems. Further, the generation of these volatiles was studied in two different baked food products

Beef Flavor Myology

It has been well established that cooking method, marbling level, and cooked internal temperature endpoint affect beef flavor, the most important driver of consumer acceptance. However, beef cuts respond differently to cooking method and cooked internal temperature endpoint based on their inherent chemical characteristics. Treatments were: beef cuts (inside round, bottom round, and eye of round); USDA beef quality grade (upper two-thirds Choice and Select); cooking methods (pan grill, stir fry, stew no marinade, stew marinade, and roast); and internal cook temperature endpoints (58°C, 70°C, and 80°C). The pan grill cook method included 0.64 and 1.91 cm samples from each muscle type. The stir fry cook method treatment was limited to 0.64 cm cuts, which were cut into 2.54 cm strips prior to cooking. The marinated and non-marinated stew cook method treatments included 0.64 and 1.91 cm samples from each muscle. These samples were then cut into 0.64 x 2.54 x 2.54 cm and 1.91 x 2.54 x 2.54 cm samples prior to cooking. Stew marinated samples were marinated with 118 mL water, 90 mL lemon juice, 30 mL canola oil, 5 mL salt, and 2.5 mL pepper. 0.91 kg roasts were cut from bottom round, eye of round, and inside round subprimals prior to cooking. An expert descriptive beef flavor and texture attribute panel evaluated each sample using 16-point scales for flavor and texture attributes. Warner-Bratzler shear force (WBSF) were determined. The trained panel results and WBSF values were analyzed using Proc Means and Proc GLM procedures of SAS (version 9.4, SAS Institute, Cary, NC) with a predetermined alpha of 5%. Quality grade impacted flavor for the inside round (P< 0.05). USDA quality grade had minimal effect on tenderness as expected, as beef round cuts are high use muscles and contain high amounts of connective tissue. Cooking method and internal cook temperature endpoint, or cooking time for the stewing cooking treatment impacted beef flavor to a greater extent (P< 0.05). When pan fried, thicker cuts resulted in more positive flavor attributes. For cuts that were roasted, cooking to higher internal temperatures resulted in higher levels of beef identity, roasted, and umami flavors and less serumy/bloody flavors, as well as decreased tenderness (P< 0.0001), especially in inside round roasts. Marinated round cuts were more tender than their non-marinated counterparts (P < 0.0001). Cuts that were thinner and had longer cooking times were more tender, but had more off-flavor attributes (P < 0.05). Cut thickness, cooking method, length of cooking or internal cook temperature endpoint, and presence of marinade affected flavor and texture of bottom round, eye of round, and inside round cuts. This data will be useful in providing consumer and food service personnel recommendations on how to maximize the flavor and texture of beef round cuts