Salt-Promoted Fibrillation of Legume Proteins Enhanced Interfacial Modulus for Stabilization of HIPEs Encapsulating Carotenoids with Improved Nutritional Performance.

The thermal acidic-treatment-induced fibrillation of legume proteins isolated from cowpea and mung bean was demonstrated to be promoted by salt. Worm-like thin prefibrilar intermediates were formed in low salt concentrations (0-75 mM), which twisted to be the thick and mature amyloid-like fibrils with multistrands as the salt content was elevated (150-300 mM). Absorption of the fibrils fabricated in high salt concentrations to the oil/water interface constructed the protein layer with a significantly higher interfacial modulus compared with the one formed by the fibrils fabricated in low salt concentrations. Consequently, they showed the superiority in stabilizing high internal phase emulsions (HIPEs) with oil volume fraction ratios higher than 74%. HIPEs stabilized by the high salt-concentration-induced legume protein fibrils had stronger capabilities not only in encapsulating liposoluble carotenoids but also in protecting their stability against heating, ultraviolet, and iron ion stimulus, compared with the one stabilized by the low-salt-concentration-induced legume protein fibrils. Bioaccessibilities of the carotenoids in simulating gastrointestinal (GI) digestion were significantly improved after encapsulation by the HIPEs, which were interestingly increased with the elevation of salt concentrations utilized for preparing the legume protein fibrils. Furthermore, the carotenoids-loading-HIPEs were injectable and showed in vivo nutritional functions of mitigating colitis.

Interfacial Protein Fibril Polymorphisms Regulate In Vivo Adipose Expansion for Control of Obesity.

Obesity is becoming a worldwide pandemic. Interfacial engineering of food lipid is expected to inhibit diet-induced obesity without damage to the eating enjoyment brought by high-fat diets. Unfortunately, this strategy has not been achieved yet. After screening different plant proteins, bromelain and papain were found to form wormlike and long-straight protein fibrils, respectively. The conversion of long-straight amyloid-like fibrils to wormlike fibrils was demonstrated in the fibrillation of bromelain. Using oil-in-water high internal phase emulsions (HIPEs) as a proof of concept, bromelain fibrils showed dramatically stronger interfacial stabilization capabilities than papain fibrils with high application potentials in the real-world formulation of high-fat food products such as mayonnaise. Compared with papain fibrils, oral administration of HIPEs stabilized by bromelain fibrils resulted in substantially higher fecal lipid contents and significantly decreased expression levels of the genes related to lipid absorption and transport in the intestine, including CD36, FATP-2, FATP-4, and APOA-4, without a difference in intervening gut microbiota. Consequently, dramatically less lipid absorption in the small intestine, markedly smaller chylomicron particles in the plasma, lower serum triglycerides, and controlled energy and lipid metabolism, as well as the inhibition of adipose expansion and overweight, were observed in the group with gavage of HIPEs stabilized by the bromelain fibrils rather than the papain fibrils. Furthermore, with the same calorie, substitution of all the fat in the standard high-fat feed of mice with the HIPEs emulsified by the bromelain fibrils showed a significantly stronger effect than the ones prepared by the papain fibrils on preventing high-fat-diet (HFD)-induced obesity including alleviation of adipose expansion and inflammation as well as fatty liver, also via inhibiting the absorption and transport of lipid in the intestine. The effect is ascribed to the suppressed lipolysis caused by a more compact and elastic interfacial layer formed by the wormlike fibrils than that of the long-straight fibrils, which are resistant to gastric environments and replacement by bile acids in digestion. Therefore, we provide an appealing and general strategy for controlling obesity by reducing the supply of free fatty acids (FAs) for absorption in the enteric lumen through protein fibril polymorphisms at the interface.

Lonicera japonica polysaccharides alleviate D-galactose-induced oxidative stress and restore gut microbiota in ICR mice.

Lonicera japonica polysaccharides (LJPs) exhibit anti-aging effect in nematodes. Here, we further studied the function of LJPs on aging-related disorders in D-galactose (D-gal)-induced ICR mice. Four groups of mice including the control group, the D-gal-treated group, the intervening groups with low and high dose of LJPs (50 and 100 mg/kg/day) were raised for 8 weeks. The results showed that intragastric administration with LJPs improved the organ indexes of D-gal-treated mice. Moreover, LJPs improved the activity of superoxide dismutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-Px) and decreased the malondialdehyde (MDA) level in serum, liver and brain. Meanwhile, LJPs restored the content of acetylcholinesterase (AChE) in the brain. Further, LJPs reversed the liver tissue damages in aging mice. Mechanistically, LJPs alleviate oxidative stress at least partially through regulating Nrf2 signaling. Additionally, LJPs restored the gut microbiota composition of D-gal-treated mice by adjusting the Firmicutes/Bacteroidetes ratio at the phylum level and upregulating the relative abundances of Lactobacillaceae and Bifidobacteriacesa. Notably, the KEGG pathways involved in hazardous substances degradation and flavone and flavonol biosynthesis were significantly enhanced by LJPs treatment. Overall, our study uncovers the role of LJPs in modulating oxidative stress and gut microbiota in the D-gal-induced aging mice.