In recent years, there has been an increase in pesticide use to improve crop production due to the growth of agricultural activities. Consequently, various pesticides have been present in the environment for an extended period of time. This review presents a general description of recent advances in the development of methods for the quantification of pesticides used in agricultural activities. Current advances focus on improving sensitivity and selectivity through the use of nanomaterials in both sensor assemblies and new biosensors. In this study, we summarize the electrochemical, optical, nano-colorimetric, piezoelectric, chemo-luminescent and fluorescent techniques related to the determination of agricultural pesticides. A brief description of each method and its applications, detection limit, purpose—which is to efficiently determine pesticides—cost and precision are considered. The main crops that are assessed in this study are bananas, although other fruits and vegetables contaminated with pesticides are also mentioned. While many studies have assessed biosensors for the determination of pesticides, the research in this area needs to be expanded to allow for a balance between agricultural activities and environmental protection.

Pineapple waste is an underexplored source for producing nanocomposites, from which nanocellulose, namely cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs), can be produced. This review summarizes extraction methods from different pineapple residues (leaves, crown leaves, stem, peel, pulp, and pomace), covering top-down processes (hydrolysis, oxidation, carboxymethylation, and mechanical fibrillation) and bottom-up strategies (ionic liquids and deep eutectic solvents). The review examines the influence of the morphology and crystallinity of nanocellulose on the functional performance of the nanocomposites. Strategies for processing pineapple-derived nanocellulose composites are analyzed by technique (solution casting, film stacking, and melt blending/extrusion) and polymer matrices (starch, PVA, chitosan, PLA, PHBV, PBAT, proteins, and polysaccharides), including typical loading levels for most polymer-reinforced systems (0.5–5 wt.%), while higher levels (15–50 wt.%) are used in particular cases such as PVA, CMC, and cellulosic matrices. The impact on mechanical strength, barrier behavior, UV shielding, and optical properties is summarized, along with reports of self-reinforced and hybrid cellulose-derived matrices. A benchmarking section was prepared to show nanocellulose loading ranges, trends in properties, and processing-relevant information categorized by type of matrix. Finally, the review describes the potential roles of pineapple waste within a bioeconomy context and identifies some extraction by-products that could be incorporated into diverse value chains.

Organic conductive polymers have been widely used as active layers in bioelectronic devices. In this work, a novel approach to entrap enzymes directly into the conductive active layer is described, using a polysaccharide as a surfactant. The surfactant allowed the electropolymerization from a micellar media and it acted as a doping agent in the conductive polymer. Gold nanotriangles were added to the matrix in order to enhance the enzymatic product quantification. The composition and oxidation state of the biocompatible conductive layer were confirmed by infrared spectrophotometric and Raman studies. Meanwhile, the gold nanotriangles presence, distribution and electrochemical activity were studied by transmission electron microscopy, atomic force microscopy, dynamic light scattering and cyclic voltammetry techniques. The inhibition of the enzyme, due to the presence of pesticides, was used to electrochemically quantify their concentration in real water samples. The concentration was confirmed by gas and liquid chromatography. Therefore, this novel composite active layer allows building a biosensor with suitable performance for an early warning in environmental control, especially in countries highly impacted by agricultural activities.

Pineapple leaf fibers (PALFs), obtained from abundant yet underutilized pineapple leaf residues, represent a promising feedstock for producing fibrillated cellulose. In this work, cellulosic fibers were isolated and characterized by Fiber Quality Analysis (FQA), showing lengths between 0.33 and 0.47 mm and widths of 12.2 µm after organosolv pulping using ethanol and acetic acid as a catalyst, followed by hydrogen peroxide bleaching with diethylenetriaminepentaacetic acid as a chelating agent. The cellulosic fibers were then subjected to TEMPO-mediated oxidation and subsequently disintegrated by microfluidization to produce micro-/nanofibrillated cellulose (MNFC) with a carboxylate content of 0.85 and 1.00 mmol COO⁻/g, zeta potential of −41 and −53 mV, and average widths of 15 and 12 nm for unbleached and bleached nanofibrils, respectively. The nanofibrillation yields were 73% and 68% for the bleached and unbleached MNFC samples, indicating the presence of some non-fibrillated or partially fibrillated fractions. X-ray diffraction analysis confirmed preservation of cellulose type I crystalline structure, with increased crystallinity, reaching 85% in the bleached MNFC. These findings demonstrate the feasibility of a sequential process, combining organosolv pulping, hydrogen peroxide bleaching, TEMPO-mediated oxidation, and microfluidization, for preparing MNFC from pineapple leaf fibers. Overall, this study highlights pineapple leaf residues as a sustainable source of MNFC, supporting strategies to transform agricultural waste into valuable bio-based materials.