Comparative study on structural characterization, physicochemical properties, and in vitro probiotic activities of resistant starch from different varieties of Euryale ferox

Summary

Euryale ferox, a nutritious aquatic plant, contains two varieties with significantly different health benefits. North Euryale ferox has much higher levels of resistant starch (a special type of starch that resists digestion) compared to South Euryale ferox, making it potentially more beneficial for gut health and diabetes management. The resistant starch in this plant acts as a prebiotic, promoting the growth of beneficial gut bacteria while inhibiting harmful bacteria, supporting overall digestive and metabolic health.

Background

Euryale ferox (EF) is a highly nutritious aquatic crop that serves as an excellent source of resistant starch (RS). Two main cultivated varieties exist: North Euryale ferox (NEF) with a spiny seed coat and South Euryale ferox (SEF) which is spineless. Although both varieties are consumed differently in traditional and modern applications, the structural and functional differences between their resistant starches remain unclear.

Objective

This study aimed to comprehensively compare the structural characterization, physicochemical properties, and in vitro probiotic activities of resistant starch extracted from North and South Euryale ferox varieties. The research sought to elucidate why these two varieties have distinct applications and to identify novel RS5 amylose-lipid complexes within EF.

Results

NEFRS exhibited significantly higher RS content (∼10%) compared to SEFRS (∼4%) with superior crystallinity, thermal stability, and molecular order. Both displayed A-type crystalline structures, with RS5 amylose-lipid complexes being more abundant in NEFRS. Four bound fatty acids were identified: palmitic, linoleic, trans-oleic, and stearic acids. EFRS enhanced growth of beneficial bacteria while NEFRS showed stronger inhibition against pathogenic bacteria including E. coli and S. aureus.

Conclusion

This study systematically revealed significant differences in resistant starch content and structure between North and South Euryale ferox varieties, with NEFRS demonstrating superior structural stability and probiotic properties. The identification of RS5 amylose-lipid complexes in EF represents a novel finding with implications for functional food development. These insights provide valuable information for optimizing EF processing and developing functional food products tailored to different applications.
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