Identification of off-flavor compounds in high-density polyethylene (HDPE) with different amounts of abscents

The use of synthetic pipes for drinking water distribution has increased. High desnity polyethylene (HPDE) is preferred because of its favorable mechanical properties, ease of handling during manufacturing, and low permeability to external contaminants. Off-flavor drinking water is a problem with plastic pipes. The compounds causing off-flavors are mainly carbonyl compounds. A combined zeolite called Abscents is used to eliminate odors and to remove odor-causing compounds. In this study, four different amounts of Abscents were added to raw HDPE pellets, and the influence on the off-flavor properties were analyzed. When the maximum amount of Abscents was added, almost all the carbonyl compounds disappeared, and the intensities of odors also decreased. The use of Abscents notably increased the acceptability of HDPE pipes. The system used for analysis of volatile organic compounds was a gas chromatographic/mass spectrometric/sniffing system. Purge and trap techniques were used to introduce the volatile, off-flavor components into the gas chromatograph.     

Metabolic Fate of Lignin in Birch Glucuronoxylan Extracts as Dietary Fiber Studied in a Rat Model

Scope

While previously considered inert, recent studies suggest lignin metabolism with unknown metabolic fates is occurring in the gastrointestinal tract of several animal models. This study focuses on analyzing the potential metabolites of lignin.

Methods and results

The diets of rats include relatively pure birch glucuronoxylan (pureGX) with residual lignin or lignin-rich GX (GXpoly) in their diet. Nuclear magnetic spectroscopy of the lignin isolated from the GXpoly-fed rats fecal sample shows high alteration in chemical structure, whereas lignin-carbohydrate complexes (LCCs) are enriched in fecal samples from the pureGX group. Moreover, the increased syringyl-to-guaiacyl (S/G) ratio suggests that lignin G-units are predominantly metabolized based on pyrolysis gas chromatography–mass spectrometry (pyr-GC/MS). The presence of small phenolic metabolites identified in urine samples of the GXpoly group, for example, ferulic and sinapic acids, their sulfate and glucuronide derivatives, and 4-sulfobenzylalcohol, suggests that the small fragmented lignin metabolites in the large intestine enter the plasma, and are further processed in the liver. Finally, the relative abundances of polyphenol-degrading Enterorhabdus and Akkermansia in the gut microbiota are associated with lignin metabolism.

Conclusion

These findings give further evidence to lignin metabolism in the gut of nonruminants and provide insight to the potential microbes and metabolic routes.     

6G and the UN SDGs: Where is the Connection?

Wireless Personal Communications - Sustainability has entered all aspects of life, calling for an active approach from the wireless and mobile communications community to help in solving...     

Characterization of Internal and Surface Lipids of Oat Starches from Two Isolation Processes

Oat starches representing two different isolation methods were studied for lipid contents and compositions. One of the starch isolation methods utilized water and the other slightly alkaline solution. The internal lipids were practically identical in both starches. However, starch from the alkaline method contained 21% less non-starch lipids as total fatty acids, 63% less Kjeldahl nitrogen, and the content of non-starch free fatty acids was low. Instead, starch from the water method contained almost three fold higher amounts of free fatty acids which contributed up to 49% of non-starch lipids. Therefore, it was concluded that isolation of starch under alkaline conditions both reduces the content of non-starch lipids and maintains a better composition in the residual starch lipids.