An Overview of Plant Phenolics Measurement

Abstract

Plant phenolics are widely distributed in nature and are well known for their remarkable antioxidative properties in biological systems such as plants and non-biological systems such as foods. Substantial work has been done to measure plant phenolics in different matrices; the four common steps involved in a measurement process are sampling, sample preservation, sample preparation, and analysis. This review addresses how sampling and sample preservation affect phenolic compounds levels and stability in different plant materials. Other important measurement factors including various sample extraction techniques and analysis methods are also reviewed in this paper.

Advances in the Study of Selenium‐Enriched Probiotics: From the Inorganic Se into Se Nanoparticles

“…Endemic Se deficiency is a worldwide nutritional problem, making Se supplementation a top priority. [ 15 ] Se‐enriched probiotics effectively relieve this problem with their remarkable safety, high activity and high utilization rate. However, the mechanisms of Se in metabolism such as what substance reduces the selenate to selenite remain to be further investigated.…”

“…However, the probiotics themselves can produce some characteristic changes during the Se enrichment process, such as the transformation of more vigorous metabolites including extracellular polysaccharides, bacteriocins, antimicrobial peptides, and organic acids. [ 15 ] These changes endue the Se‐enriched probiotics with more functional properties than the non‐Se probiotics. Se‐enriched probiotics have been widely used in animal husbandry and biomedical field, and their application is listed in Table 1 .…”

“…[ 80 ] It has been shown that anaerobic reduction involves nitrate reductases and/or selenate reductases, sulfhydryl groups of peptides or proteins (such as GSH), but such a complex process needs further investigation. [ 15,80–82 ] Recent research has shown that B. subtilis 168 reduces the production of SeNPs by selenite under aerobic conditions, which offers a novel insight into the molecular mechanisms of Se (VI) reduction in aerobic bacteria. Furthermore, this study identified PutC, GabD, and CysJI (cysteine [Cys]) as novel bacterial aerobic Se (IV) reductases and demonstrated for the first time that the proline metabolism pathway and the sulfite metabolism pathway were involved in the reduction of sodium selenite in B. subtilis .…”

“…Despite massive research work, the mechanism by which SeNPs are assembled remains unclear. [ 15 ] In the assembly process, small nanoparticles (behave as seeds of nucleation) will grow into large SeNPs by further aggregation, which resembles the Ostwald ripening mechanism. [ 97,98 ] Reduction of selenite to Se (0) occurs intracellularly, in the periplasmic space, or extracellularly, in different microorganisms, and thus SeNPs can grow either intracellularly or extracellularly.…”