Yogurt is one of the most emblematic and popular fermented foods. It is produced by the fermentation of milk lactose by bacteria such as Streptococcus thermophilus and Lactobacillus acidophilus. Magnetic (MNPs) and gold nanoparticles (AuNPs) were incorporated into the exopolysaccharides (EPSs) of these bacteria. The functionalized bacteria were characterized by UV-vis spectroscopy and transmission electron microscopy. A large number of MNPs and AuNPs were bound to the bacterial EPS. Interestingly, the nanoparticles’ (NPs) presence did not affect the bacteria’s capacity to ferment milk and to produce magnetic and golden yogurts. Magnetic and golden yogurts represent the perfect combination of emblematic food and nanoparticles and have a range of potential biomedical applications: use in iron-deficiency anemia, diagnosis and hyperthermia treatment of appropriate digestive diseases, and interest in glamour cuisine.

Despite the environmental concerns raised every year by the generation of high volumes of wet olive pomace, it contains valuable phenolic compounds that are essential for the valorization of this by-product. In this work, an integrated process to recover phenolic compounds from wet olive pomace is proposed. It consists of ultrasound-assisted solid-liquid extraction, followed by ultrafiltration and nanofiltration. Several commercial membranes were studied at different operational conditions. The ultrafiltration stage allowed the purification of biophenols, which were obtained in the permeate stream. Regarding organic matter, satisfactory rejection values were obtained with both commercial UH030 and UP005 membranes (Microdyn Nadir), but the latter provided more efficient purification and higher values of permeate flux, above 18 L·h⁻¹·m⁻² at 2.5 bar and 1.5 m·s⁻¹. Later, this permeate stream was concentrated by means of a nanofiltration process, obtaining polyphenol rejection values that surpassed 85% with the commercial NF270 membrane (DuPont), then achieving the concentration of the previously purified polyphenols.

The textile industry is one of the largest water consumers, and, as a result of its activity, it generates tons of wastewater. In this research, forward osmosis has been employed to tackle the critical need of treating textile wastewater. The HFFO2 membrane (Aquaporin) was used to process large volumes of real cotton dyeing wastewater, wool dyeing wastewater, and several types of textile end-of-pipe wastewater. In all cases, the permeate flux was between 6 and 8 L·h^{− 1} m^{− 2} during the major part of the process. The recovery of clean water from each wastewater surpassed 90 %, whereas the membrane rejected more than 87 % of total dissolved solids. As a result, textile dyes were concentrated on the feed side of the membrane, which enables their recovery and potential reutilization in a subsequent dying process, along with the reclaimed water. The HFFO2 membrane was efficiently cleaned by a backwash process, restoring the initial water flux. These results indicate the suitability of forward osmosis to reuse dyes and water from textile wastewater, reducing the environmental impact of this industry and favoring its sustainability.

Phenolic compounds from a hydroalcoholic extract of wet olive pomace were purified and concentrated by an integrated membrane process in organic media. First, UF010104 (Solsep BV) and UP005 (Microdyn Nadir) membranes were tested to be implemented in the ultrafiltration stage, with the aim of purifying the extract and obtaining a permeate enriched in phenolic compounds. Despite the high flux observed with the UF010104 membrane (20.4 ± 0.7 L·h⁻¹·m⁻², at 2 bar), the UP005 membrane was selected because of a more suitable selectivity. Even though some secoiridoids were rejected, the permeate stream obtained with this membrane contained high concentrations of valuable simple phenols and phenolic acids, whereas sugars and macromolecules were retained. Then, the ultrafiltration permeate was subjected to a nanofiltration step employing an NF270 membrane (DuPont) for a further purification and fractionation of the phenolic compounds. The permeate flux was 50.2 ± 0.2 L·h⁻¹·m⁻², working at 15 bar. Hydroxytyrosol and some phenolic acids (such as vanillic acid, caffeic acid, and ferulic acid) were recovered in the permeate, which was later concentrated by reverse osmosis employing an NF90 membrane. The permeate flux obtained with this membrane was 15.3 ± 0.3 L·h⁻¹·m⁻². The concentrated phenolic mixture that was obtained may have important applications as a powerful antioxidant and for the prevention of diabetes and neurodegenerative diseases.