Miguel Peris

A 21st century technique for food control: Electronic noses

This work examines the main features of modern electronic noses (e-noses) and their most important applications in food control in this new century. The three components of an electronic nose (sample handling system, detection system, and data processing system) are described. Special attention is devoted to the promising mass spectrometry based e-noses, due to their advantages over the more classical gas sensors. Applications described include process monitoring, shelf-life investigation, freshness evaluation, authenticity assessment, as well as other general aspects of the utilization of electronic noses in food control. Finally, some interesting remarks concerning the strengths and weaknesses of electronic noses in food control are also mentioned.

Review: Highlights in recent applications of electronic tongues in food analysis

This paper examines the main features of modern electronic tongues (e-tongues) and their most important applications in food analysis in this new century. The components of an e-tongue (automatic sampler, array of chemical sensors, and data processing system) are described. Applications commented include process monitoring, freshness evaluation and shelf-life investigation, authenticity assessment, foodstuff recognition, quantitative analysis, and other quality control studies. Finally, some interesting remarks concerning the strengths and weaknesses of e-tongues in food analysis are also mentioned.

On-line monitoring of food fermentation processes using electronic noses and electronic tongues: A review

Fermentation processes are often sensitive to even slight changes of conditions that may result in unacceptable end-product quality. Thus, close follow-up of this type of processes is critical for detecting unfavorable deviations as early as possible in order to save downtime, materials and resources. Nevertheless the use of traditional analytical techniques is often hindered by the need for expensive instrumentation and experienced operators and complex sample preparation. In this sense, one of the most promising ways of developing rapid and relatively inexpensive methods for quality control in fermentation processes is the use of chemical multisensor systems. In this work we present an overview of the most important contributions dealing with the monitoring of fermentation processes using electronic noses and electronic tongues. After a brief description of the fundamentals of both types of devices, the different approaches are critically commented, their strengths and weaknesses being highlighted. Finally, future trends in this field are also mentioned in the last section of the article.

A Wireless Sensor Network approach for distributed in-line chemical analysis of water.

In this work we propose the implementation of a distributed system based on a Wireless Sensor Network for the control of a chemical analysis system for fresh water. This implementation is presented by describing the nodes that form the distributed system, the communication system by wireless networks, control strategies, and so on. Nitrate, ammonium, and chloride are measured in-line using appropriate ion selective electrodes (ISEs), the results obtained being compared with those provided by the corresponding reference methods. Recovery analyses with ISEs and standard methods, study of interferences, and evaluation of major sensor features have also been carried out. The communication among the nodes that form the distributed system is implemented by means of the utilization of proprietary wireless networks, and secondary data transmission services (GSM or GPRS) provided by a mobile telephone operator. The information is processed, integrated and stored in a control center. These data can be retrieved--through the Internet--so as to know the real-time system status and its evolution.

Present and future of expert systems in food analysis

Abstract This paper presents an overview of the most relevant contributions in the field of expert system (ES) applications in chemical analysis of foods, along with a critical discussion of future, would-be developments. It illustrates the possibilities offered as well as the fact that quality control laboratories should be aware of the power of artificial intelligence that modern computer technology affords. It is worth noting that the applications described are straightforward with a certain versatility and can, therefore, be implemented for other analytes and/or food samples. Special attention is devoted to the promising distributed knowledge-based systems due to their potential advantages over the existing centralized approaches, as inferred from a recent example of application to the on-line monitoring of some key chemical parameters in the course of a food production process. Short and middle term predictions concerning the potential of ES in food analysis are also made.

Distributed expert systems as a new tool in analytical chemistry

Abstract This article emphasizes the growing importance of artificial intelligence in the automation of chemical analysis processes. Nevertheless, the authors predict that the use of centralized knowledge-based systems – though not still consolidated – will probably be replaced by distributed expert systems with their multiple advantages (discussed in the article). Distributed expert systems, which are based on the utilization of highly intelligent analytical instrumentation connected by means of communication networks, permit the implementation of highly flexible control systems that are capable of adapting themselves to different situations. At the same time, it is possible to take advantage of the power offered by the new communication technologies in the field of analytical chemistry. Distributed expert systems are thoroughly described and illustrated with a detailed example of an application to the monitoring and control of an alcoholic fermentation process by means of on-line/in-line chemical analysis; this can be extended to any other process whose chemical parameters undergo variations in the course of time.

An Overview of Recent Expert System Applications in Analytical Chemistry

Abstract A review is presented with references to the most important work dealing with the applications of artificial intelligence (expert systems, knowledge-based systems) in both qualitative and quantitative analytical chemistry. Contributions from January 1990 to date are briefly described together with some reviews and monographs on this matter. Topics covered include instrumental analysis, especially spectroscopy and chromatography, data management, chemometrics, process automation, and spectrum interpretation.

An expert system as a tool for the specification and intelligent control of a flow injection analysis system

Abstract An expert system was designed with the intention that it should fully control a fermentation process, whose on-line monitoring is based on the determination of total acidity, reducing sugars, ethanol and pH all along the process. The expert system is then in charge of deciding when and which measurements are to be carried out according to the previously obtained results and a pre-determined set of rules. Additionally, the expert system is able to take decisions concerning possible malfunctions.

Rule nets: application to the advanced automation of a flow-injection analysis system

Abstract An expert system based on rule nets has been developed. This new tool—the rule net—consists of a set of conditional-type propositions which are mutually bound. In this work, a set of rule nets has been implemented by means of a self-developed pack called AUTOMAT. Time has been incorporated into the reasoning of the expert system in such a way that it is able to carry out the on-line monitoring of an alcoholic fermentation process.

Monitoring of a wort fermentation process by means of a distributed expert system

Abstract A distributed expert system has been proposed for the monitoring of a wort fermentation process through the flow injection determination of total acidity, reducing sugars, ethanol and pH. Its configuration is mainly based on the use of distributed nodes connected by means of a network and is capable of adapting itself to different situations. Satisfactory results have been obtained when it has been applied in a brewery plant, important advantages being shown over previously implemented centralized knowledge-based systems.