Microstructural and functional transformations induced by germination and digestion in Lupinus angustifolius L

Area of Science:

• Food Science and Technology
• Biotechnology
• Nutritional Biochemistry

Background:

• Legume germination is a bioprocess to enhance nutritional quality.
• Lupinus angustifolius is a high-protein legume with potential for food innovation.
• Limited data exists on how germination impacts lupin flour's structural, functional, and digestive properties.

Purpose of the Study:

• To evaluate the effect of germination time on the structural composition, morphology, and digestibility of Lupinus angustifolius flours.
• To understand microstructural transformations and their impact on functional properties.
• To assess the potential of germinated lupin flour in novel food development.

Main Methods:

• Germination of Lupinus angustifolius seeds for 0, 3, 5, and 7 days.
• Analysis of proximate composition (lipids, protein, fiber) and starch fractions (resistant and rapidly digestible starch).
• Histological, spectroscopic, viscosity, thermal stability, and simulated gastrointestinal digestion analyses.

Main Results:

• Germination altered macronutrient profiles, increasing protein (25% to 29.2%) and fiber (9.9% to 13.4%), while decreasing lipids (24.9% to 12.1%).
• Starch fractions shifted towards increased resistant starch (0.02% to 0.24%) and rapidly digestible starch (0.86% to 1.55%).
• Microstructural changes included tissue disorganization, protein hydrolysis, altered secondary structure (α-helices to β-sheets), reduced viscosity, and decreased thermal stability, leading to a fragmented matrix after digestion.

Conclusions:

• Germination significantly modifies biochemical, functional, and structural properties of lupin flour.
• The bioprocess enhances nutritional profile, digestibility, and bioactive potential of Lupinus angustifolius.
• Germinated lupin flour shows high potential for novel food applications and health benefits.