Debittering of Lupinus albus L. using subcritical water extraction

• Autor(a) principal: Vasconcelos, Maria de Medeiros
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/113512
• topic: White lupin; Lupinus albus L.; Debittering; Alkaloids; Lupanine; Subcritical Water; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

White lupin, Lupinus albus L., is a legume used for human and animal feed. It usually grows and is cultivated in the Mediterranean and the Middle East. It is rich in proteins, fibers, and carbohydrates and can replace soy consumption while decreasing soy imports in Europe. White lupin has a high content of alkaloids, which gives it a bitter taste while making it toxic to humans and animals. Lupin requires a pre-treatment that consists of cooking the lupin, followed by successive washes with water.The present work studied an alternative green method of extracting lupin alkaloids, intending to reduce water consumption. Extraction with subcritical water was the method chosen, in a batch reactor, with pressurized water to remain in a liquid state. The four parameters studied were temperature (between 100 and 140 ºC), solvent-to-solid ratio (20:1 and 40:1), simple extraction, or two successive extractions, and particle size. The white lupin seeds were crushed (particle sizes between 0.5 and 1 mm) and chemically characterized, presenting 31.5% protein, 37% carbohydrates, and 9% lipids. In the extraction studies with the lupin powder, the temperature was the parameter with the greatest impact on the remaining alkaloids content, followed by the solvent-to-solid ratio. The best result was obtained at 100 ºC with a solvent-to-solid ratio of 20:1, leading to the extraction of 71% lupanine from the lupin. Other components were co-extracted, namely carbohydrates (7 g/100 g of lupin) and protein (5 g/100 g of lupin). At these conditions, 23.7 g/100 g lupin of protein out of 31.5 g/100 g lupin remained in the lupin residue. These extraction conditions also allowed 27.8 g/100 g lupin of carbohydrates out of 37.0 g/100 g lupin to remain in the matrix. Successive extractions at 100 ºC and a 20:1 solvent-to-solid ratio with both lupin powder and whole lupin seeds showed that the second extraction barely enhanced the extraction yield of lupanine.