There is an increasing demand for more healthy and sustainable diets, which led to an interest in replacing synthetic colors with natural plant-based ones. Phycocyanin, which is commonly extracted from Spirulina platensis, has been explored as a natural blue pigment for application in the food industry. It is also used as a nutraceutical in food, cosmetic, and pharmaceutical products because of its potentially beneficial biological properties, such as radical scavenging, immune modulating, and lipid peroxidase activities. The biggest challenges to the widespread application of phycocyanin for this purpose are its high sensitivity to chemical degradation when exposed to heat, light, acids, high pressure, heavy metal cations, and denaturants. Consequently, it is of considerable importance to improve its chemical stability, which requires a thorough knowledge of the relationship between the structure, environment, and chemical reactivity of phycocyanin. To increase the application of this natural pigment and nutraceutical within foods and other products, the structure, biological activities, and factors affecting its stability are reviewed, as well as strategies that have been developed to improve its stability. The information contained in this article is intended to stimulate further studies on the development of effective strategies to improve phycocyanin stability and performance.

Flammulina velutipes polysaccharides (FVP) have been proved to be effective in improving learning and memory impairment in mice. However, their underlying mechanism remains unclear. The aim of this study was to investigate the relationship between memory improvement and gut microbiota regulation of FVP. The results showed a significant decrease in the relative abundances of Clostridia and Bacilli but a significant increase in Bacteroidia, Erysipelotrichia and Actinobacteria in the FVP-treated group versus the control group. Fecal microbiota transplantation of mice with ‘FVP microbiota’ derived from FVP-fed mice resulted in improved learning and memory function compared to colonization with ‘common microbiota’ derived from control individuals. FVP and ‘FVP microbiota’ significantly increased the numbers of platform crossings and the swimming distance of mice in the probe test and decreased the escape latency and total swimming distance of mice in the hidden platform test. Moreover, FVP and ‘FVP microbiota’ regulated cytokines, such as IL-1β, TNF-α, IL-6 and IL-10, suggesting a mechanism involving the suppression of neuroinflammation. This study indicated that the regulation of the gut microbiome may have a causal role in improving scopolamine-induced impairment of learning and memory.

Edible mushrooms are rich sources of bioactive components. In this study, a bioactive protein, PEP, was isolated from an edible mushroom, Pleurotus eryngii, through (NH₄)₂SO₄ precipitation and ion-exchange chromatography. Proteomic analysis by matrix assisted laser desorption ionization-time of flight mass spectrometry showed that PEP was a novel protein with a molecular weight of 40 kDa. PEP exhibited anti-inflammatory effects in LPS-stimulated RAW 264.7 macrophages by inhibiting the overproduction of pro-inflammatory mediators including nitric oxide (NO), cytokine IL-1β and IL-6. It was further demonstrated that these anti-inflammatory effects of PEP were associated with the inhibition of inducible nitric oxide synthase (iNOS) expression, and the deactivation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Our results demonstrated that PEP might be a good candidate for anti-inflammation in the gastrointestinal tract, especially in the colon.