White lupine (Lupinus albus) and Andean lupine (L. mutabilis) flours suitable for consumption: physico-chemical and functional characteristics

Abstract

Introduction: lupins are legumes that are a source of nutrients and phytochemicals with beneficial properties for health. However, they present alkaloids that must be eliminated prior to consumption. The objective of the work was to obtain and characterize White and Andean lupine flours suitable for consumption.

Materials and method: the grains were debittered using traditional aqueous method that included soaking for 18 hours, cooking for 1 hour and washing for 5 days. Then, they were dried in an oven, ground and sieved. Alkaloids, proteins, fats, total dietary fiber, sodium, phosphorus, color, absorption rate and water solubility, total polyphenols, flavonoids, carotenoids and phenol profile in raw seeds and treated flours were determined.

Results: the alkaloid contents of treated flours were within the limits established for safe intake (less than 0.07 g/100g). Proteins were found between 25-39 g/100g, fats between 12-23 g/100g, total dietary fiber 35-50 g/100g and ash 1.5-3.3 g/100g. Calcium was found between 210-323 mg/100g, phosphorus 140-202 mg/100g and sodium 38-44 mg/100g. The color corresponded to yellow with a tendency to red. The treated Andean lupine flour presented a higher rate of water absorption (7.8 g/g) and solubility in water (78.8%). The treated products presented polyphenols (13.4 and 20.8 mg/100g), flavonoids (27.5 and 8.7 mg/100g) and carotenoids (0.3 and 0.9 mg/100g). The phenolic profile corresponded to 3 flavones and 3 isoflavones in white lupine. In Andean lupine, 5 flavones and 3 isoflavones were detected.

Conclusion: the treated flours could represent alternative ingredients to the traditional ones such as wheat and soy for the formulation of healthy foods.