In Vitro Fermentation Shows Polyphenol and Fiber Blends Have an Additive Beneficial Effect on Gut Microbiota States.

Polyphenols and fermentable fibers have shown favorable effects on gut microbiota composition and metabolic function. However, few studies have investigated whether combining multiple fermentable fibers or polyphenols may have additive beneficial effects on gut microbial states. Here, an in vitro fermentation model, seeded with human stool combined from 30 healthy volunteers, was supplemented with blends of polyphenols (PP), dietary fibers (FB), or their combination (PPFB) to determine influence on gut bacteria growth dynamics and select metabolite changes. PP and FB blends independently led to significant increases in the absolute abundance of select beneficial taxa, namely Ruminococcus bromii, Bifidobacterium spp., Lactobacillus spp., and Dorea spp. Total short-chain fatty acid concentrations, relative to non-supplemented control (F), increased significantly with PPFB and FB supplementation but not PP. Indole and ammonia concentrations decreased with FB and PPFB supplementation but not PP alone while increased antioxidant capacity was only evident with both PP and PPFB supplementation. These findings demonstrated that, while the independent blends displayed selective positive impacts on gut states, the combination of both blends provided an additive effect. The work outlines the potential of mixed substrate blends to elicit a broader positive influence on gut microbial composition and function to build resiliency toward dysbiosis.

Long-Term Vitamin Stabilization in Low Moisture Products for NASA: Techniques and Three-Year Vitamin Retention, Sensory, and Texture Results.

Multiyear spaceflight will require innovative strategies to preserve vitamins in foods, in order to retain astronaut health and functionality long-term. Furthermore, space foods must be low weight/volume to comply with cargo restrictions, and must retain sensory quality to ensure consumption. Low water activity products were developed, fortified with vitamins A, B1, B9, C, and E at twice their spaceflight requirements, stored for three years at 21 °C and one year at 38 °C, and analyzed annually for retained vitamin content and organoleptic quality. The vitamins were encapsulated in carbohydrate or lipid coatings and tested in relatively low and high fat versions of compressed bars and powdered drink mix formulations. Susceptibility to degradation at 21 °C followed the sequence B9 > A > B1 > C > E; degradation rates were fitted to first-order kinetics. Vitamins A and C were more sensitive at the higher storage temperature. Vitamin retention was slightly higher in compressed bars verses powders. Effects of matrix lipid level on stability were vitamin dependent. Sensory characteristics for products stored three years at 21 °C remained mostly above 6.0 on a 9-point hedonic scale, whereas those stored for one year at 38 °C remained mostly above 5.0. Compressed bars firmed significantly during storage. All vitamin levels after three years at 21 °C remained above the space flight requirements, demonstrating the suitability of the selected fortification schemes and food matrices for long-term preservation. PRACTICAL APPLICATION: Vitamins A, B1, B9, C, and E were retained at 70% to 95% levels for three years at 21 °C in carefully formulated, fortified low water activity products. Product compression and vacuum packaging slightly helped to further preserve vitamins. The sensory quality of these products was retained throughout storage.