Time-dependent fermentation of different structural units of commercial pectins with intestinal bacteria.

Many of the proposed health-related properties of pectins are based on their fermentability in the large intestine, but detailed structure-related studies on pectin fermentation have not been reported so far. Here, pectin fermentation kinetics were studied with a focus on structurally different pectic polymers. Therefore, six commercial pectins from citrus, apple, and sugar beet were chemically characterized and fermented in in vitro fermentation assays with human fecal samples over different periods of time (0 h, 4 h, 24 h, 48 h). Structure elucidation of intermediate cleavage products showed differences in fermentation speed and/or fermentation rate among the pectins, but the order in which specific structural pectic elements were fermented was comparable across all pectins. Neutral side chains of rhamnogalacturonan type I were fermented first (between 0 and 4 h), followed by homogalacturonan units (between 0 and 24 h) and, at last, the rhamnogalacturonan type I backbone (between 4 and 48 h). This indicates that fermentation of different pectic structural units might take place in different sections of the colon, potentially affecting their nutritional properties. For the formation of different short-chain fatty acids, mainly acetate, propionate, and butyrate, and the influence on microbiota, there was no time-dependent correlation regarding the pectic subunits. However, an increase of members of the bacterial genera Faecalibacterium, Lachnoclostridium, and Lachnospira was observed for all pectins.

Time Trends of Tetrahydrocannabinol (THC) in a 2008-2021 German National Survey of Hemp Food Products.

∆9-Tetrahydrocannabinol (THC) is known as the main psychotropic compound present in the hemp plant. It also occurs in commercially available hemp food products and may have adverse effects on consumers. This article provides an overview of the current situation of the THC content in hemp food products in Germany in recent years. The content of THC was evaluated in a data set of 5 different hemp food product groups (tea, seeds, seed oils, food supplements, and nonalcoholic beverages) comprising 511 samples. For the toxicological assessment, the THC intake was estimated and the exhaustion of acute reference dose (ARfD) and lowest observed adverse effect level (LOAEL) was calculated using average daily consumption scenarios. Data show that hemp beverages and seeds typically do not contain amounts of THC that can exceed toxicological thresholds. On the contrary, hemp food supplements, such as cannabidiol (CBD) products, can contain high levels of THC, since the THC content of 18% of the samples has the potential to exceed the LOAEL and 8% even exceed the minimum intoxication dose. However, a significant linear decrease in the THC content of hemp food supplements was observed between 2018 and 2021 (n = 111, R = -0.36, p < 0.0001). A problematic food group is also tea based on flowers, leading to an increase in overall THC levels in recent years. Regulation of low-THC products within the framework of controlled distribution of cannabis for recreational use appears to be advisable.