Mechanistic study of the solid-liquid extraction of phenolics from walnut pellicle fibers enhanced by ultrasound, microwave and mechanical agitation forces.

The molecular diffusion of phenolics inside walnut pellicle fiber particles under solid-liquid extraction enhanced by ultrasound (US), orbital agitation (OA), impeller agitation (IA), and the combined microwave and impeller agitation (MW-IA) were explored. Numerical modeling considering the temperature-dependent diffusivity revealed that the internal diffusivity of phenolics was the highest under MW-IA and the lowest under OA. At 35 °C, IA (126.246 mg/g, t = 10 min) was more effective to strengthen the phenolic diffusivity than the US-39W (95.538 mg/g, t = 10 min). Due to the simultaneous enhancement of internal diffusivity and external dissolution, the MW-IA extraction reached equilibrium within 16 min, reaching the highest yield among all the treatments (176.944 mg/g). The extraction was then divided into the increasing and falling driving force periods. The comparison of phenolic diffusivity among MW-IA and IA roughly indicated that the proportion of non-thermal effect of microwave at 315 W was 889% higher than 189 W at the extraction equilibrium. Moreover, some soluble polyphenols, i.e. quercitrin and syringic acid, could be adsorbed by the cell wall after equilibrium. The correlations between any two soluble phenolics varied with the phenolic type, deducing that soluble phenolics may interact with each other either positively or negatively. Besides, the mining of phenolic data also indicated that intensive impeller agitation is a good substitution for ultrasonication to extract phenolics effectively.

In vitro gastrointestinal digestion and fecal fermentation reveal the effect of different encapsulation materials on the release, degradation and modulation of gut microbiota of blueberry anthocyanin extract.

In this study, four different selected wall materials (namely gelatin, soy protein isolate, maltodextrin and Arabic gum) were applied for blueberry anthocyanin extract encapsulation. The effect of these wall material types on the release and degradation of anthocyanin and the modulation of gut microbiota during in vitro simulated gastrointestinal digestion and colonic fermentation were investigated. It was found that the encapsulation of anthocyanin extract using appropriate wall material could significantly enhance the colonic accessibility of anthocyanins. Soy protein isolate and gelatin delayed the release of anthocyanins, whereas the other two wall materials displayed no significant effect on the release time of anthocyanins. Gut microbiota mainly metabolized some phenolic compounds such as 4-hydroxycinnamic acid and chlorogenic acid. Meanwhile, different fermented anthocyanin extract microcapsule broth could significantly decrease the composition and abundance of Firmicutes and increase that of Bacteroidetes. Furthermore, the presence of anthocyanin extract microcapsules, especially those encapsulated with soy protein isolate, promoted the biosynthesis of short-chain fatty acids by gut microbiota. It is concluded that, amongst the wall materials studied, soy protein isolate appeared to be a functional and suitable candidate to delay anthocyanin release and prevent disease through the promotion of gut health.

Purification, preliminary characterization and in vitro immunomodulatory activity of tiger lily polysaccharide.

A water-soluble polysaccharide (LLPS) from tiger lily was extracted by ultrasonic wave-assisted extraction. The LLPS, which was isolated by alcohol precipitation, was further purified by DEAE Sepharose Fast Flow and Sephadex G-100 chromatography, which resulted in LLPS fractions in LLPS-1, LLPS-2 and LLPS-3, with molecular weights of 350.5, 403.3 and 146.2kDa, respectively. LLPS-1 and LLPS-2 primarily consisted of glucose and mannose in a molar ratio of nearly 1:2 and 1:1, respectively. In contrast, LLPS-3 was primarily composed of arabinose, galactose, glucose and mannose in a molar ratio of nearly 2:2:2:1. LLPS fractions could stimulate the proliferation of macrophages. The in vitro immunomodulatory activity of the fractions was evaluated. The results showed that treatment with 25-400 µg/mL of LLPS fractions could increase phagocytic activity and nitric oxide production of macrophages in a dose-dependent manner.

Physiological and biochemical metabolism of germinating broccoli seeds and sprouts.

Changes in physiological and biochemical metabolism as well as glucoraphanin and sulforaphane contents of germinating broccoli seeds and sprouts were investigated in this study. Sprout length, root length, and fresh weight increased with germination time. Dry weight varied from 2.5 to 3.0 mg per sprout. A rapid increase in respiratory rate of sprouts occurred between 24 and 36 h of germination and then stayed at a high level. HPLC analysis found that glucoraphanin content increased at the early stage (0-12 h) of germination, decreased to a low value of 3.02 mg/g at 48 h, and then reached the highest value of 6.30 mg/g at 72 h of germination. Sulforaphane content decreased dramatically during the first day of germination, then increased slowly, and reached a high value of 3.38 mg/g at 48 h before declining again.