This study evaluated the antioxidant properties and chemical composition of the seeds, pulp and peels of Ungurahua (Oenocarpus bataua) and Pasu (Gustavia macarenensis)—fruits, native to the Ecuadorian Amazon. The antioxidant capacity was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and cyclic voltammetry (antioxidant index 50 (AI₅₀)) assays; differential pulse voltammetry was used to evaluate antioxidant power using the electrochemical index. The total phenolic content, as well as the yellow flavonoid and anthocyanin content, were quantified via spectrophotometry. In addition, the trans-resveratrol and ascorbic acid content were evaluated through high performance liquid chromatography (HPLC). Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to identify secondary metabolites with possible therapeutic properties. Results showed that the Pasu peel and seed extracts had the highest antioxidant capacity, followed by the Ungurahua peel; these results were consistent for both spectroscopic and electrochemical assays. HPLC and UPLC-MS analysis suggest that Oenocarpus bataua and Gustavia macarenensis are important sources of beneficial bioactive compounds.

The native berries of South America present promising marketing opportunities owing to their high antioxidant content, notably rich in anthocyanin and phenolic compounds. However, Ecuador's endemic fruits, primarily found in the wild, lack comprehensive data regarding their phytochemical composition and antioxidant capacity, underscoring the need for research in this area. Accordingly, this study evaluated the total phenolic, anthocyanin, flavonoid, resveratrol, ascorbic acid, citric acid, sugars, and antioxidant content of three native Ecuadorian fruits: mora de monte (Rubus glabratus Kunth), mortiño (Vaccinium floribundum Kunth), and tuna de monte (Opuntia soederstromiana). Determination of resveratrol, ascorbic acid, citric acid, and sugars was determined by HPLC analysis, and UPLC analysis was used to determine tentative metabolites with nutraceutical properties. Antioxidant capacity was assessed using cyclic voltammetry and the DPPH method; differential pulse voltammetry was used to evaluate antioxidant power. Analysis of results through UPLC-QTOF mass spectrometry indicated that R. glabratus Kunth and V. floribundum Kunth are important sources of various compounds with potential health-promoting functions in the body. The DPPH results showed the following antioxidant capacities for the three fruits: R. glabratus Kunth > O. soederstromiana > V. floribundum Kunth; this trend was consistent with the antioxidant capacity results determined using the electrochemical methods.

The electro-oxidation of p-Benzoquinone (p-BQ) was investigated in a flow-by reactor (FM01-LC) without separation, with two boron-doped diamond (BDD) electrodes as both the anode and cathode, in batch recirculation mode. The optimal operating conditions were determined using response surface methodology, specifically a face-centered central composite design. The initial pH (pH₀) and applied current density (j) were evaluated as factors, while the p-BQ (η (%)) served as the response variable. The optimal conditions, a pH₀ of 6.52 and a j of 0.124 A/cm², achieved a maximum removal efficiency of 97.32% after 5 h of electrolysis. The specific energy consumption and total operating cost were 127.854 kWh/m³ and USD 3.7 USD/L, respectively.

Pineapple biomass represents an abundant renewable source of carbon and a promising feedstock with considerable potential for the production of sustainable fuels. In the present study, the influence of liquid hot water (LHW) pretreatment on the pineapple mother plant was investigated at different controlled severities, then characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results show that LHW pretreatment causes structural changes, leading to lignin and hemicellulose depolymerization up to a severity factor of 2.36–3.55, whereas at severity factors in the range of 4.13–5.90, cellulose, hemicellulose, and lignin appear to repolymerize. This pretreatment resulted in a higher hydrolysis efficiency (94.92 ± 0.04%) at 50 °C for 72 h. Compared with the untreated sample, the hydrolysis rate under these conditions increased by a factor of 2.16. SEM imaging revealed significant disruption of the PMP microstructure following LHW treatment, while XRD data confirmed an increase in the crystallinity index. FTIR analysis further indicated modifications in functional group profiles, supporting the structural and compositional changes induced by pretreatment. Overall, this study demonstrates the effectiveness of LHW pretreatment in enhancing the enzymatic digestibility and modifying the physicochemical properties of PMP biomass, providing a foundation for its valorization into high value bioproducts.

Bioenergy underpins a wide variety of technologies to transform biomass into fuels, chemicals, and biomaterials through sustainable routes. Significant advances in biomass valorization towards understanding their potential for energy production have occurred over the last decades. However, the complexity gap to utilize the entire lignocellulosic biomass (LCB) simultaneously remains overwhelming largely, which severely impedes the development of a bioresources-based economy. The exploration of complex characteristics of LCB fractions, including both chemical and structural aspects, is imperative. In the present study, 17 Ecuadorian LCB were prepared and extensively characterized to understand their compositional and structural characteristics through analytical approaches such as carbon–hydrogen–nitrogen–sulfur analysis, bomb calorimetry, X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared spectroscopy. Regarding volatile matter content, all biomass sources presented remarkable levels ranging from 65.01 to 86.13%. Ash content was found in a range of 5.67 to 17.53%. Results show that the banana pseudostem displayed the highest cellulose content (59.56%). The lowest cellulose content was recorded in oil palm kernel shell (9.55%). The largest calorific value was found in sugarcane bagasse (22.62 MJ kg−1), while the minimum (12.50 MJ kg−1) was found in banana rachis. The highest crystallinity index was observed in rice husk followed by rice straw and plantain pseudostem. These results provide scientific guidance on the potential of collected biomasses as promising candidates for bioenergy production and related industrial applications.