The valorization of agri-food by-products is a critical pathway toward building sustainable food systems, reducing waste, and advancing the circular economy. This review aims to identify recent advances, key challenges, and future perspectives in this field. We conducted a critical and systematic synthesis of 159 peer-reviewed studies (2019–2025) selected based on quality and thematic relevance from leading international databases. The analysis focuses on emerging technologies such as ultrasound-assisted extraction, microencapsulation, spray drying, lyophilization, deep eutectic solvents, and colloidal systems, emphasizing their efficiency in recovering bioactive compounds from agro-industrial by-products. Significant challenges include industrial scalability, economic feasibility, regulatory compliance, and consumer acceptance. This paper also discusses current applications in functional foods and nutraceuticals, outlining promising directions for the sector. Although challenges remain, the findings offer valuable insights for researchers, industry, and policymakers aiming to foster sustainable innovation and implement strategies aligned with circular economy principles.

Native potato clones grown in Peru contain bioactive compounds beneficial to human health. This study aimed to optimize the spray-drying nanoencapsulation of native potato phenolic extracts utilizing a central composite design and response surface methodology, obtaining the optimal treatment to an inlet temperature of 120 °C and an airflow of 141 L/h in the nano spray dryer B-90, which allowed maximizing the yield of encapsulation, antioxidant capacity (DPPH), encapsulation efficiency (EE), total phenolic compounds, and total flavonoids; on the other hand, it allowed minimizing hygroscopicity, water activity (Aw), and moisture. Instrumental characterization of the nanocapsules was also carried out, observing a gain in lightness, reddening of the color, and spherical nanoparticles of heterogeneous size (133.09–165.13 nm) with a negative ζ potential. Thermal, infrared, and morphological analyses confirmed the encapsulation of the core in the wall materials. Furthermore, an in vitro release study of phenolic compounds in an aqueous solution achieved a maximum value of 9.86 mg GAE/g after 12 h. Finally, the obtained nanocapsules could be used in the food and pharmaceutical industry.

Ethanolic extracts of propolis and bee honey contain substances beneficial to human health. Mixtures of wall materials were compared in spray-drying microencapsulation of ethanolic extracts of propolis and bee honey rich in bioactive compounds. Maltodextrin and tara gum were used to obtain microencapsulates A, and modified native potato starch and tara gum were used for microencapsulates B. High values of phenolic compounds, flavonoids, and antioxidant capacity were obtained in microcapsules A and B, and the results obtained in terms of encapsulation efficiency, yield, hygroscopicity, solubility, moisture, Aw, bulk density, and color were typical of the spray-drying process. On the other hand, spherical and elliptical microparticles of sizes between 7.83 and 53.7 µm with light and medium stability were observed. Thermogravimetric properties were similar in both microencapsulates; total organic carbon, SEM-EDS, and FTIR analyses corroborated the encapsulation. X-ray diffractogram exhibited amorphous structures, and the release kinetics of phenolic compounds presented high values from 8.13 to 12.58 mg GAE/g between 7 and 13 h. Finally, modified potato starch is a better encapsulant than maltodextrin because it has better core protection and controlled release of the encapsulated bioactive compounds.

Propolis is a substance with significant anti-inflammatory, anticancer, and antiviral activity, which could be used more efficiently at the nano level as an additive in the food industry. The aim was to obtain and characterize nanoencapsulated multi-floral propolis from the agro-ecological region of Apurimac, Peru. For nanoencapsulation, 5% ethanolic extracts propolis with 0.3% gum arabic and 30% maltodextrin were prepared. Then, the mixtures were dried by nano spraying at 120 °C using the smallest nebulizer. The flavonoid content was between 1.81 and 6.66 mg quercetin/g, the phenolic compounds were between 1.76 and 6.13 mg GAE/g, and a high antioxidant capacity was observed. The results of moisture, water activity, bulk density, color, hygroscopicity, solubility, yield, and encapsulation efficiency were typical of the nano spray drying process. The total organic carbon content was around 24%, heterogeneous spherical particles were observed at nanometer level (between 11.1 and 562.6 nm), with different behaviors in colloidal solution, the thermal gravimetric properties were similar in all the encapsulates, the FTIR and EDS analysis confirmed the encapsulation and the X-ray diffraction showed amorphous characteristics in the obtained material; stability and phenolic compound release studies indicated high values of 8.25–12.50 mg GAE/g between 8 and 12 h, the principal component analysis confirmed that the flora, altitude, and climate of the propolis location influenced the content of bioactive compounds, antioxidant capacity, and other properties studied. The nanoencapsulate from the district of Huancaray was the one with the best results, allowing its future use as a natural ingredient in functional foods. Nevertheless, technological, sensory, and economic studies should still be carried out.

The contamination of water resources by effluents from various industries often contains heavy metals, which cause irreversible damage to the environment and health. The objective was to evaluate different biosorbents from the weed Rumex acetosella to remove metal cations in wastewater. Drying, grinding and sieving of the stems was carried out to obtain the biomass, retaining the fractions of 250 to 500 µm and 500 to 750 µm, which served to obtain the biosorbents in natura (unmodified), acidic, alkaline, and mixed. Proximal analysis, PZC, TOC, removal capacity, influence of pH, functional groups, thermal analysis, structural characteristics, adsorption isotherms, and kinetic study were evaluated. The 250 µm mixed treatment was the one that presented the highest removal percentages, mainly due to the OH, NH, -C-H, COOH, and C-O functional groups achieving the removal of up to 96.14% of lead, 36.30% of zinc, 34.10% of cadmium and 32.50% of arsenic. For contact times of 120 min and an optimum pH of 5.0, a loss of cellulose mass of 59% at 328 °C and a change in the surface of the material were also observed, which allowed for obtaining a topography with greater chelating capacity, and the Langmuir and pseudo-second order models were better fitted to the adsorption data. The new biosorbents could be used in wastewater treatment economically and efficiently.

Tara gum, a natural biopolymer extracted from Caesalpinia spinosa seeds, was investigated in this study. Wall materials were produced using spray drying, forced convection, and vacuum oven drying. In addition, a commercial sample obtained through mechanical methods and direct milling was used as a reference. The gums exhibited low moisture content (8.63% to 12.55%), water activity (0.37 to 0.41), bulk density (0.43 to 0.76 g/mL), and hygroscopicity (10.51% to 11.42%). This allows adequate physical and microbiological stability during storage. Polydisperse particles were obtained, ranging in size from 3.46 µm to 139.60 µm. Fourier transform infrared spectroscopy characterisation confirmed the polysaccharide nature of tara gum, primarily composed of galactomannans. Among the drying methods, spray drying produced the gum with the best physicochemical characteristics, including higher lightness, moderate stability, smaller particle size, and high glass transition temperature (141.69 °C). Regarding rheological properties, it demonstrated a non-Newtonian pseudoplastic behaviour that the power law could accurately describe. The apparent viscosity of the aqueous dispersions of the gum decreased with increasing temperature. In summary, the results establish the potential of tara gum as a wall material applicable in the food and pharmaceutical industries.