Historical Evolution and Food Control Achievements of Near Infrared Spectroscopy, Electronic Nose, and Electronic Tongue—Critical Overview

Abstract

Amid today’s stringent regulations and rising consumer awareness, failing to meet quality standards often results in health and financial compromises. In the lookout for solutions, the food industry has seen a surge in high-performing systems all along the production chain. By virtue of their wide-range designs, speed, and real-time data processing, the electronic tongue (E-tongue), electronic nose (E-nose), and near infrared (NIR) spectroscopy have been at the forefront of quality control technologies. The instruments have been used to fingerprint food properties and to control food production from farm-to-fork. Coupled with advanced chemometric tools, these high-throughput yet cost-effective tools have shifted the focus away from lengthy and laborious conventional methods. This special issue paper focuses on the historical overview of the instruments and their role in food quality measurements based on defined food matrices from the Codex General Standards. The instruments have been used to detect, classify, and predict adulteration of dairy products, sweeteners, beverages, fruits and vegetables, meat, and fish products. Multiple physico-chemical and sensory parameters of these foods have also been predicted with the instruments in combination with chemometrics. Their inherent potential for speedy, affordable, and reliable measurements makes them a perfect choice for food control. The high sensitivity of the instruments can sometimes be generally challenging due to the influence of environmental conditions, but mathematical correction techniques exist to combat these challenges.

Standardized Extraction Techniques for Meat Analysis with the Electronic Tongue: A Case Study of Poultry and Red Meat Adulteration

“…The purpose of this, was to achieve good sensor signals from the instrument during measurement and so as to allow rapid detection of low concentration differences in the meat mixture samples otherwise, known as fingerprinting. The main operating principle of measurement for the e-tongue is based on the difference in potential changes of sensor probes (BB, HA, ZZ, GA CA, JE, JB) against a reference electrode in zero-current conditions [ 20 , 42 ]. Each replicate sample from the determination of optimal dilution and the different extraction methods, was measured four times.…”

“…Common examples are mass spectrometry [ 10 ], polymerase chain reaction (PCR) [ 11 , 12 ] and enzyme-linked immunosorbent assay (ELISA) [ 13 ]. Due to cost, accuracy, reliability, less sophistication, and speed of the analytical process, other methods such as spectroscopy [ 7 , 14 , 15 , 16 , 17 ] and machine learning-enabled smart sensor systems [ 18 ], such as the electronic nose (e-nose) [ 8 , 9 , 19 , 20 ] and electronic tongue [ 19 ], have become more preferred methods for detecting meat adulteration. Both spectroscopy and e-nose are non-invasive techniques but spectroscopy operates on the principle of how the meat sample reacts with electromagnetic waves in a defined wavelength whereas, e-nose operates on the principle assessing odor signatures from the meat sample through high sensitivity sensors [ 20 ].…”

“…Due to cost, accuracy, reliability, less sophistication, and speed of the analytical process, other methods such as spectroscopy [ 7 , 14 , 15 , 16 , 17 ] and machine learning-enabled smart sensor systems [ 18 ], such as the electronic nose (e-nose) [ 8 , 9 , 19 , 20 ] and electronic tongue [ 19 ], have become more preferred methods for detecting meat adulteration. Both spectroscopy and e-nose are non-invasive techniques but spectroscopy operates on the principle of how the meat sample reacts with electromagnetic waves in a defined wavelength whereas, e-nose operates on the principle assessing odor signatures from the meat sample through high sensitivity sensors [ 20 ]. The electronic tongue (e-tongue) is another high sensitivity sensor based instrument capable of discriminating food products through pattern recognition [ 21 ] and has been used for both quantitative and qualitative environmental monitoring [ 22 ], pharmaceutical [ 23 ] and food analysis [ 22 , 24 , 25 ].…”

“…Unlike spectroscopy and e-nose however, e-tongue is equipped with high sensitivity sensors that measure taste compounds/dissolved components. A detailed head-to-head comparison of some of these instruments and their applications have been reported [ 5 , 9 , 20 , 26 ] but this current study will focus solely on the e- tongue. Ideally, the e-tongue is better suited for liquid samples and combination with chemometric techniques, it has been used to monitor the quality of coffee [ 27 ], wine [ 24 , 28 , 29 ], fruit juice [ 24 ], oils [ 25 , 30 , 31 ], tea [ 32 ], and recently in some semi-solid foods like tomato concentrate [ 33 ].…”

“…Ideally, the e-tongue is better suited for liquid samples and combination with chemometric techniques, it has been used to monitor the quality of coffee [ 27 ], wine [ 24 , 28 , 29 ], fruit juice [ 24 ], oils [ 25 , 30 , 31 ], tea [ 32 ], and recently in some semi-solid foods like tomato concentrate [ 33 ]. With mathematical correction methods [ 28 , 29 , 32 , 34 ], signals from the e-tongue sensors can be further optimized to compensate for issues of drift that could arise from environmental factors, such as temperature, relative humidity, etc., or sensor aging [ 5 , 20 , 28 ].…”