Harmful substances in food and agricultural environments pose significant risks to human health, necessitating the development of sensitive detection technologies. Electrochemical sensors are ideal for rapid monitoring because of their low cost, high efficiency, and portability. Recently developed laser-induced graphene (LIG)-based electrochemical sensors have demonstrated exceptional potential owing to the unique structural properties and outstanding electrochemical performance of LIG. In this review, the key factors influencing the LIG material characteristics during fabrication are discussed. Then, LIG-based electrochemical sensors are systematically categorized as pristine LIG and nanomaterial-functionalized, biomaterial-modified, and polymer-functionalized electrochemical sensors, and their application in the detection of functional components, additives, and agrochemicals in food products, and the detection of environmental pollutants, is comprehensively analyzed. Finally, the current challenges and the directions for future development are discussed.

Portable and low-cost analytical devices are essential for rapid detection of bioactive substrates in agricultural products. This study presents the first highly integrated microelectrochemical sensor based on pencil graphite for rapid and sensitive detection of hesperidin in Citrus reticulate ‘Chachi’ peel. The surface morphology and characterization as well as the electrochemical property of pencil graphite was investigated and discussed. A high electrocatalytic efficiency of hesperidin has been found at used pencil graphite-based microelectrodes. Kinetic analysis was carried out to further understand the electrochemical process of hesperidin at a pencil graphite microelectrode. Consequently, a portable and highly-integrated microelectrochemical sensor exhibits a sensitivity of 0.7251 μA cm⁻² μM⁻¹ and a detection limit as low as 25 nM (S/N = 3), and high selectivity was fabricated. Proposed microelectrochemical sensors were applied to electrochemically determinate the hesperidin content in the extract of Citrus reticulata “chachi” peel. As a result, the concentration of hesperidin in the actual real sample detected electrochemically with the proposed portable and low-cost microelectrochemical sensors is highly consistent to that obtained with a common chromatographic method, thus indicating the good reliability and that it can be used in practical applications.

Exocarpium Citri Grandis (ECG) is a distinctive medicinal and edible product originating from southern China and is often covered with a layer of characteristic “white frost” (WF). This study investigated the composition, formation mechanism, microbial safety, and anti-inflammatory activity of the WF. Multi-technique analyses revealed that WF mainly consisted of crystalline naringin (~80% of total mass). Drying-induced shrinkage and rupture of oil glands on ECG suggested metabolite migration and surface crystallization as the key mechanisms for WF formation. Microbial profiling revealed no significant differences in fungal and bacterial communities between WF and non-frost (NF) samples, and none of eight common mycotoxins was detected, confirming its microbial safety. Brewing tests demonstrated that water boiling for 30 min achieved efficient extraction of naringin, with higher yields in WF samples than in NF samples. In RAW264.7 cells, both WF and NF extract significantly inhibited lipopolysaccharide-induced NO production as well as the secretion and transcription of TNF-α, IL-6, IL-1β, iNOS, and NF-κB, with WF extract showing a stronger effect. Overall, these findings indicate that WF originates from endogenous flavonoid crystallization rather than microbial contamination and enhances the anti-inflammatory activity. This study provides a scientific basis for quality evaluation, processing optimization, and standardization of ECG products.