Matrix solid-phase dispersion (MSPD) and modified QuEChERS methods were compared for the extraction of pesticide residues from onion followed by determination by liquid chromatography with electrospray ionization tandem mass spectrometry. The efficiency of the methods was statistically compared using recovery and precision data, matrix effects and other extraction characteristics such as the sample mass, solvent volume, extraction time and limits of detection and quantification (LOQ). In general, faster extractions and lower LOQ values (0.0005 to 0.05 mg kg⁻¹) were achieved with QuEChERS, whereas greater ruggedness and lower matrix effects were obtained with MSPD. For both methods, high extraction yields were achieved (61.8–120%) with relative standard deviations lower than 20%. Matrix effects were observed for both methods, and were compensated by using matrix-matched calibration.

The use of food packaging derived from petroleum-based polymers has developed significant environmental problems, as these materials require centuries to degrade and release hazardous pollutants. Consequently, the food industry is shifting toward biodegradable alternatives developed from agro-industrial by-products, such as proteins, polysaccharides, and lipids. Whey protein is a by-product of the cheese industry, which is emerging as a promising material for producing edible and biodegradable films with effective barrier properties. Whey-based films can be incorporated with bioactive compounds, particularly phenolic compounds. These substances, naturally present in fruits, legumes, and vegetable waste, possess potent antimicrobial and antioxidant activities that are essential for extending the shelf life of perishable foods. This review provides a systematic evaluation of how the incorporation of phenolic compounds influences the physicochemical and bioactive properties of whey-based films. Thus, an analysis of film-forming methods, the interaction between protein matrices and phenolic compounds, and a critical discussion of the challenges remaining for their industrial application as active food packaging were evaluated. The discussion focuses on how the incorporation of phenolic extracts influences the physicochemical, mechanical, and barrier properties of the films, as well as their antioxidant and antimicrobial efficiency. The novelty of this review lies in its comprehensive focus on the sustained release of phenolic compounds from a whey protein film and their application in real food systems. By utilizing these natural additives, the industry can provide sustainable alternatives to synthetic preservatives. Active whey protein packaging represents a viable strategy to inhibit food spoilage, prevent lipid oxidation, and maintain sensory quality, while reducing the environmental problems.