Evaluation of the bioaccessibility of carotenoid esters from Lycium barbarum L. in nano-emulsions: A kinetic approach.

Lycium barbarum L., known as goji berry, is a rich source of carotenoid esters, which are mainly composed of zeaxanthin dipalmitate (ZDP), lutein palmitate (LP), ß-cryptoxanthin palmitate (ß-CP), zeaxanthin palmitate (ZP), zeaxanthin myristate palmitate (ZMP), and zeaxanthin palmitate stearate (ZPS). Oil-in-water nano-emulsions containing carotenoid esters from L. barbarum L. with olive oil (ON) and soybean oil (SN) were prepared to investigate the liberation and bioaccessibility (BA) of in vitro digestion. The particle sizes of ON and SN were approximately 160 nm stabilized with sucrose esters and monoacylglyceride as emulsifiers. ON presented an equal liberation of each carotenoid ester as SN, except that LP had a high value. Incorporation of carotenoid esters into the micelle were evaluated using a fractional conversion model, containing two phases, namely, a rapid growth rate for the first phase, and then reaching a plateau for the second phase. The kinetic rate was related to the particle size, oil type and carotenoid ester nature. BA at plateau values for ZDP and ZPS were higher than that of the four other carotenoid esters in SN. Considering the great improvement of the liberation and BA, the excipient nano-emulsion prepared in this study is a good delivery system for carotenoid esters from goji berry.

Exploring microbial dynamics associated with flavours production during highland barley wine fermentation.

Highland barley wine (HBW) is a well-known grain wine in Qinghai-Tibet Plateau, China and is mainly fermented by local Qu (a traditional starter) with highland barley (Hordeum vulgare, Qingke (Tibetan hulless barley)), and the flavors profiles associated with microbiota succession during HBW fermentation are unrevealed. Hence, high-throughput sequencing (HTS) technology was used to investigate the dynamic changes of microbial community for the duration of the fermentation. In addition, metabolites were analyzed by gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC). A total of 66 volatile compounds and 7 organic acids were identified during the traditional brewing process. Results showed that the composition of microbiota varied over the fermentation process. The bacterial genera (relative abundance > 0.1%) decreased from 13 at 0 h to 4 encompassing Leuconostoc (13.53%) and Acetobacter (74.60%) after 48 h fermentation, whilst the structure of fungal community was more uniform in comparison with bacteria, as Rhizopus and Saccharomyces were predominant throughout the fermentation. Furthermore, the correlations between microbiota and the detected compounds were also explored, which highlighted that three bacterial genera, including Acetobacter, Leuconostoc, Bacillus and one fungal genus Rhizopus were significantly correlated with main flavours compounds (|r| > 0.7, FDR < 0.01). To conclude, the detailed information provided by this study offer screening strategies of beneficial bacterial and fungal strains to improve the quality of HBW.