Transformation of agricultural wastes into functional oligosaccharides using enzymes and emerging technologies

Introduction Pectin‐oligosaccharides (POS) serve diverse purposes as a food ingredient, antimicrobial and biostimulant in plants, and their functionality is linked to the degree of esterification. Grape and broccoli wastes emerge as environmentally friendly alternatives to obtaining pectin, serving as a sustainable source to producing POS. For example, microwaves have proven to be an effective and sustainable method to extract polysaccharides from plant matrices. Objective This work aims to use grape and broccoli wastes as alternative sources for obtaining pectin by microwave‐assisted extraction and biotransformation into POS, which possess biological properties. Material and Methods The extraction conditions were identified at a power of 400 W, 300 s for the extraction of pectin from grape pomace and broccoli waste. Biotransformation of pectins into POS, using commercial enzyme preparations (Viscozyme L and Pectinase). Characterisation was carried out by Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Results Physicochemical analysis indicated grape pomace and broccoli waste pectins had galacturonic acid content of 63.81 ± 1.67 and 40.83 ± 2.85 mg 100 mg−1, low degree of esterification of 34.89% and 16.22%, respectively. Biotransformation of pectins into POS resulted in a 20% hydrolysis rate. The main enzymatic activity was polygalacturonase for the degradation of the main structure of the pectin. Conclusion Production of POS from agro‐industrial wastes by emerging technologies, such as the combined use of microwave‐assisted extraction and enzymatic processes, represents an alternative method for the generation of bioactive compounds with distinctive properties suitable for different applications of interest. Grape and broccoli waste, regarded as environmentally friendly alternatives, are explored for sustainable pectin production, specifically pectin‐oligosaccharides. Microwave‐assisted extraction (MAE), optimised at 400 W for 300 s, utilised galacturonic acid content and degree of esterification as indicators. Commercial enzymes (Viscozyme L and Pectinase) facilitated a 20% hydrolysis rate. Physicochemical analysis revealed grape pomace and broccoli waste pectins with galacturonic acid content of 63.81 ± 1.67 and 40.83 ± 2.85 mg 100 mg−1, and low degree of esterification of 34.89% and 16.22%, respectively. This study showcases a sustainable approach for generating bioactive pectin‐oligosaccharides,