Preparation of astaxanthin-rich nanoparticulate fermented duck sausages with nitrite-reducing Lactobacillus: enhanced antioxidant capacity and reduced nitrite

Nitrite is a major hazardous substance in fermented sausages, and excessive human intake poses health risks. This study aimed to develop a low-nitrite fermented duck sausage. Lactic acid bacteria (LAB) can effectively degrade nitrite; astaxanthin exhibits excellent antioxidant and colorant properties, and nanoencapsulation technology can improve astaxanthin stability. Additionally, milk fat globule membrane-enriched whey protein powder (MFGM-WPI) is a promising food-grade encapsulation wall material. In this study, a selected strain of Lactobacillus sakei was combined with other LAB as the starter culture for duck sausage fermentation. Furthermore, gum arabic and MFGM-WPI were used as raw materials to prepare a novel astaxanthin nanoparticle additive, which aimed to improve the color of the sausage and endow it with antioxidant effects. The results showed that the fermented duck sausages added with astaxanthin-rich nanoparticles and composite LAB exhibited superior color stability and textural properties, characterized by a reddish hue, reduced nitrite content, and enhanced astaxanthin levels. Among all tested fermented duck sausage groups (including the natural fermentation group, single LAB fermentation group, and free astaxanthin-added group), the specific group (astaxanthin-rich nanoparticles + composite LAB) exhibited the highest 1,1-diphenyl-2-picrylhydrazyl radical and hydroxyl radical scavenging activities, alongside the lowest peroxide value. In conclusion, the combination of composite LAB strains and astaxanthin nanoparticles represents a potentially effective strategy for reducing nitrite content and enhancing the antioxidant capacity of fermented duck sausages.