Green tea kombucha, produced using a green tea (Camellia sinensis) grown in Brazil, was characterized and its in vitro bioactive properties were evaluated. Overall, 92 phenolic compounds were identified (70.7% flavonoids, 25% phenolic acids, 2.2% lignans, and 1.1% other polyphenols), contributing to the observed high antioxidant capacity. The major phenolics identified were gallocatechin, catechin 5-O-gallate, and epicatechin. Green tea kombucha exhibited antibacterial activity against all tested bacteria, being more effective against Salmonella spp. In addition, green tea kombucha demonstrated antimalarial activity against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum, and antiproliferative activity against cancer cell lines A549, HCT8, HepG2, and HUVEC. Additionally, it presented antioxidant properties by effectively reducing the generation of reactive oxygen species (ROS) and provided protection to erythrocytes against AAPH-induced oxidative stress. Thus, green tea kombucha is abundant in antioxidants and possesses intriguing bioactive properties that can be investigated by both the food and pharmaceutical sectors.

The effect of dehulling and cooking on the in vitro digestibility, and phenolic profiles was evaluated for four Dutch sorghum varieties (HD7 and HD19, Sorghum bicolor; and HD100 and HD101 Sorghum nigricans) bred in the Netherlands. Protein content ranged from 9 to 14 % and grains with black pericarp were more resistant to dehulling. Essential amino acids composition analysis showed that the lysine chemical score (∼0.6) was lower than that required for adults. Phenolic profiling by UHPLC-ESI-QTOF/MS allowed annotaion of 219 phenolic compounds, with flavonoids as the most representative class (91 %). Dehulling and genotype had stronger influence on the phenolic profiles than cooking; however, hydrothermal treatment was essential for the depolymerization of proanthocyanidin dimers and trimers. The combination of dehulling and boiling improved in vitro protein digestibility and increased in vitro bioaccessibility of key phenolic compounds. These processes are effective for developing high-quality sorghum-based products using Dutch varieties.

Untargeted metabolomics is a powerful tool with high resolution and the capability to characterize a wide range of bioactive natural products from fruit and vegetable by-products (FVB). Thus, this approach was applied in the study to evaluate the phenolic compounds (PC) by metabolomic screening in five FVB after optimizing their extraction. The total phenolic content and antioxidant activity analyses were able to select the best extractor (SM) and ultrasonication time (US) for each FVB; methanol was used as a control. Although ultrasonication yielded a lower number of PC identifications (84 PC), the US extract was the most efficient in total ionic abundance (+21% and +29% compared to the total PC and SM extracts, respectively). Ultrasonication also increased the phenolic acid (+38%) and flavonoid classes (+19%) extracted compared to SM, while the multivariate analyses showed the control as the most dissimilar sample. FVB extracted from the same parts of the vegetable/fruit showed similarities and papaya seed presented the most atypical profile. The application of the metabolomics approach increased the knowledge of the bioactive potential of the evaluated residues and possibilities of exploring and valorizing the generated extracts.

Brewer’s spent grain (BSG), the major by-product of the brewing industry, is an abundant lignocellulosic biomass rich in phenolic compounds, although their association with the cell wall matrix limits their recovery and functional application. This study aimed to enhance phenolic compound recovery from BSG by integrating solid-state fermentation (SSF) with Aspergillus oryzae and green extraction technologies and to stabilize the recovered compounds using nanostructured lipid carriers (NLCs). Fermentation was evaluated for up to 7 days. Fermented and unfermented BSG were subsequently subjected to pressurized liquid extraction (PLE) and microwave-assisted extraction (MAE) with ethanol at 50–150 °C. Phenolic recovery was assessed by reducing capacity, DPPH antioxidant activity, and targeted UHPLC–MS/MS profiling. A two-day SSF period was selected as optimal, increasing reducing capacity 5-fold and antioxidant activity 7-fold compared with unfermented BSG. PLE provided the most efficient extraction performance, particularly at 130–150 °C, while SSF further enhanced phenolic recovery, especially at intermediate extraction temperatures. Targeted analysis quantified 10 phenolic compounds and related compounds and revealed compound-specific responses to processing. Fermented BSG extracted by PLE at 150 °C showed the highest p-coumaric acid content (16.0 ± 0.07 µg/g BSG), whereas the maximum trans-ferulic acid content was reached after MAE at 130 °C (21.5 ± 0.09 µg/g BSG). Selected PLE extracts were successfully incorporated into carnauba wax-based NLCs, producing particles below 300 nm and encapsulation efficiencies of up to 35%. Bioprocessing integrated with green extraction substantially improved the recovery of bioactive compounds from BSG, while lipid-based encapsulation provided a promising strategy for their stabilization, supporting the sustainable valorization of this brewing by-product.