https://hdl.handle.net/10259/4569 Mon, 11 May 2026 17:56:23 GMT 2026-05-11T17:56:23Z https://hdl.handle.net/10259/10291 Reactor configuration for subcritical water extraction of pectin-derived compounds from onion peel wastes: a comparative study Benito Román, Oscar; Menalla, Enkeledo; Cantero, Danilo; Sanz Díez, Mª Teresa; Beltrán Calvo, Sagrario The increasing interest of pectin derived compounds as functional additives in the pharmaceutical and food industries demands new sources and eco-friendly extraction approaches. In this regard, onion peel wastes (OPW) hold great potential, with over 450,000 tons of OPW being discarded annually [1], despite their remarkable pectin content. Pectins are commonly extracted acid hydrolysis (pH 2, >85 °C), that yield mainly the HG domain, due to complete hydrolysis of the branched domains or enzymatic hydrolysis, which is time consuming, but yields branched pectin rich in RG-I and RG-II domains. As an alternative to the conventional process for producing pectin derived compounds (PDC), hydrothermal hydrolysis based on subcritical water (SubW) is emerging as an eco-friendly technique. SubW refers to water at temperatures ranging from 100 °C (boiling temperature) to 374 °C (critical temperature), which remains in a liquid state due to the application of pressure. SubW can facilitate the extraction of pectin from natural matrices, and by controlling the operational parameters, pectin can be tailored into smaller units with varying degrees of polymerization to produce PDC. However, in practice, accurate control of experimental conditions has emerged as the primary challenge of the SubW extraction process, which can lead to the formation of undesired degradation products, and uncontrolled molecular weight reduction of the pectin. Póster presentado en: 20th European Meeting on Supercritical Fluids (EMSF) 2024, celebrado durante los días 26-29 de mayo en Maribor (Eslovenia). Wed, 01 May 2024 00:00:00 GMT https://hdl.handle.net/10259/10291 2024-05-01T00:00:00Z https://hdl.handle.net/10259/10290 Valorization of onion skin wastes using subcritical water: flavonoids and pectin recovery Benito Román, Oscar; Sanz Díez, Mª Teresa; Beltrán Calvo, Sagrario Onion skin wastes (OSW) represent around 10% of the total onion production and end up in landfills because they are not suitable for human consumption or animal feeding. Nevertheless this non-edible brown skin and external layers of onions are rich and phenolic compounds, mainly flavonoids such as quercetin and derivatives, which are high-added valye natural antioxidants. Additionally, onion skin has gained attention as a good source of pectin. Pectin, a complex polysaccharide composed by uronic acids (66.4%) and neutral sugars (galactose, arabinose, xylose, mannose, glucose or rhamnose) in variable composition, is the major structural component onion cell walls (42,4%). Considering that according to FAO, 2020 onion worldwide production was 104 Mt, there is a great potential for the calorization of the OSW through the recovery of flavonoids and pectin. Comunicación oral presentada en: 2nd Greenering International Conference 2023, celebrada durante los días 21-23 de marzo en Valladolid (España) Sun, 01 Jan 2023 00:00:00 GMT https://hdl.handle.net/10259/10290 2023-01-01T00:00:00Z https://hdl.handle.net/10259/10289 Extraction and degradation kinetics of pectic oligosaccharides (POS) from onion skin wastes using subcritical water Benito Román, Oscar; Melgosa Gómez, Rodrigo; Illera Gigante, Alba Ester; Sanz Díez, Mª Teresa; Beltrán Calvo, Sagrario Pectic oligosaccharides (POS) have been proposed as a new class of prebiotics due to their ability to regulate microbiota in human intestine, their anti-oxidant properties compared to other commercial oligosaccharides or their anti-inflammatory and anti-obesity effects1. POS are commonly obtained by partial (acid and/or enzymatic) hydrolysis of pectin. However, the growing demand of POS as functional additives for the pharma and food industries requires new sources and greener extraction strategies. In this sense, onion skin wastes (OSW) can offer great potential, since every year more than 450,000 t of OSW are discarded2, whereas subcritical water (SubW) emerges as an interesting and environmentally friendly technique to recover different valuable compounds from natural solid matrices. Comunicación oral presentada en: 8th ISHA International Solvothermal and Hydrothermal Association 2023, celebrada el 10-13 de septiembre en Valladolid (España) Fri, 01 Sep 2023 00:00:00 GMT https://hdl.handle.net/10259/10289 2023-09-01T00:00:00Z https://hdl.handle.net/10259/10228 Optimizing pressurized hot water technology to assist the recovery of residual crude agar from the algae industry waste stream with tailorable physicochemical properties and gel texture Diop, Cherif Ibrahima Khalil; Beltrán Calvo, Sagrario; Sanz Díez, Mª Teresa Comunicación oral presentada en: The 5th International Symposium on Processing of Food, Vegetables and Fruits (ISPFVF) 2023, durante los días 22-23 de junio en University of Nottingham Malaysia (Malasia). Thu, 01 Jun 2023 00:00:00 GMT https://hdl.handle.net/10259/10228 2023-06-01T00:00:00Z