Extraction, obtention, and yielding of galacto-oligosaccharides from chickpea and lentils

MARTINS, GONÇALO N.; CARBONI ANGELA D; HUGO, AYELÉN AMELIA; CASTILHO, PAULA C.; GOMEZ-ZAVAGLIA ANDREA

Dresden

Conferencia; 3° Food Chemistry Conference; 2023

Galacto-oligosaccharides (GOS) are carbohydrates known for their prebiotic properties. They are most-commonly obtained by enzymatic synthesis, producing β-GOS from lactose, which remains in the final mixture alongside high levels of glucose. α-GOS can be obtained from Leguminosae seeds, a process that has gained attention from industry but that competes directly with food production. However, α-GOS can be recovered from the wastewaters from legumes’ soaking and cooking waters. These are common procedures to improve legumes’ organoleptic characteristics and remove compounds responsible for uncomfortable effects (e.g., flatulence or bloating) that generate waste and promote environmental pollution. The present work sees the soaking and cooking of legume seeds as extraction strategies and evaluates their α-GOS extraction yields. A possible application for the growth of lactic acid bacteria is proposed, valorising these resources.Raw chickpeas (Cicer arietinum L.) and lentils (Lens culinaris M.) were soaked (8 h – 20 °C) and/or cooked (30 min) in water. The wastewaters’ carbohydrates’ content was determined by High Pressure Liquid Chromatography with Refractive Index detection and their concentrations were expressed as g/100 g fresh extract (as is), as g/100 g dry extract (after lyophilization) and as g/100 g of dry seeds to better determine each compound’s extraction yield. Microbial growth potential was evaluated by inoculating Lactiplantibacillus plantarum CIDCA 83114 in MRS broth sans glucose and supplemented with legume extracts.Chickpeas were richer sources of GOS than lentils, while the latter provided less mono and disaccharides. Regarding legumes’ processing, soaking treatment showed the lowest extraction yields, while cooking (without soaking) led to the highest. Legume extracts showed microbial growth potential comparable to standard sugars.It was demonstrated that legumes’ soaking and cooking can be considered efficient methods for obtaining GOS, and legume’s wastewaters can be used for growing lactic acid bacteria, thus utilizing a discarded resource and producing added-value products.