# Electronic Sensing Technologies in Food Quality Assessment: A Comprehensive Literature Review
## 4 e-Nose
The benefits of electronic noses (e-noses) are tied to the specific types of sensors used. Metal oxide semiconductor sensors are highly sensitive and detect active substances as low as 1 part per million (ppm). Polymer-based sensors, on the other hand, are effective for identifying specific flavor compounds. Their sensitivity allows for detection at levels around 10 ppm. Polymer-based sensors are also more energy efficient than metal oxide semiconductor sensors. However, there are some drawbacks to using these sensors. They require high operating temperatures, sometimes reaching 400 \({}^{\circ}\)C, and strict control of experimental conditions, such as humidity, pressure, temperature, and gas velocity [15]. Additionally, a limited number of sensors are available compared to the human nose. Recent research on e-noses has led to advancements in several areas, including assessing freshness, taste, authenticity, quality control, process monitoring, traceability, and detecting pesticide \begin{table}
\begin{tabular}{c c c c} \hline \hline
**The Use of** & **LZO Marker** & **Accuracy** & **References** \\ \hline \multirow{3}{*}{_Acinetobacter jolnsonii_ XY27 in cold stored stock (_Thununus obese_)} & Benzaldehyde & \multirow{3}{*}{[123]} \\  & 1-Hexanol & & \\  & 2,4-Di-tert-butylphenol & & \\ \hline Ochratoxin A & 1-Octen-3-one and 2-octen-1-ol & & \\   in grape-based food from & biomarkers for detecting _A. carbonarius_ & Accuracy, R\({}^{2}\), and Q\({}^{2}\): 91.7\%, & \\  & & 0.882, and 0.790 & \\ \hline \multirow{3}{*}{Ant-nose} & Four VOCs: MeOH, ProH, BuOH, and EtOH & 100\% & \\ \cline{2-4}  & Six VOCs with isomers: MeOH, ProH, IPA, & & \\  & 2-BuOH, BuOH, and EtOH & & 96.7\% & \\ \hline \multirow{3}{*}{Detection of _Penicillium expansusus_ in ‘Golden Delicious’ apples} & \multirow{3}{*}{3-Methyl butan-1-ol and methyl acetate} & Diagnosis rates over 87\%; 97\% & \\  & & for samples with early stage & \\ \cline{1-1}  & & fungal infection & \\ \hline \hline \end{tabular} Abbreviations: MeOH—methanol, ProH—1-propanol, IPA—2-propanol, 2 BuOH—2-butanol, BuOH—1-butanol, EtOH—ethanol.  
\end{table} 
Table 2: Examples of VOC markers. residues [2]. A significant challenge in utilizing e-noses is the selection of appropriate sensors and developing complex recognition algorithms, especially for implementation on cost-effective devices. Nevertheless, the significance of e-noses in the food industry continues to grow [7]. Electronic sensors are becoming more prevalent in food analysis. These sensors utilize electronic noses (e-noses) equipped with neon or partially selective gas sensors, combined with data processing and pattern recognition systems, to analyze aromas without separating volatile components. This technology enables the identification of complex aroma profiles, offering a more cost-effective and efficient alternative to traditional, labor-intensive methods [115, 131]. Using electronic noses (e-noses) to monitor the freshness of food products can transform how we store food and manage our distribution networks. This innovative solution could significantly impact the food industry. As these devices evolve, incorporating advanced sensing technologies and pattern recognition algorithms, their ability to detect and analyze various volatile substances related to food spoilage will improve. Ultimately, employing e-noses as dependable freshness monitors promotes sustainability, ensures food safety, and provides consumers with a safe and uncontaminated experience [117]. Supervising and controlling production processes is essential for ensuring consistency and maintaining high food quality. One significant technological advancement in this area is the e-nose, which plays a vital role in accurately monitoring and evaluating complex production procedures, such as roasting coffee beans [132]. By analyzing subtle changes in aroma during the roasting process, e-noses enable continuous assessment of the roast level, helping to ensure product uniformity.