Does low-carbon city pilot affect the enterprise competitiveness in China? Based on a staggered difference-in-difference model.

China has recently instituted the low-carbon city pilot (LCCP) policy in target areas to control its greenhouse gas emissions. Studies examining those environmental regulations have not focused on how they affect enterprise competitiveness, especially emphasizing the LCCP's dynamic effect. Here, we use the quasi-experimental opportunities of the LCCP policy along with a staggered difference-in-difference model to evaluate and explain the influences and transmission mechanisms of the LCCP policy on enterprise competitiveness. The empirical results show that (1) the construction of low-carbon cities significantly reduces, by 3.56%, the average enterprise competitiveness. Also, capital-intensive and small firms are more susceptible to adverse effects from the LCCP policy, but those effects weaken with time. (2) The LCCP policy affects enterprise competitiveness by increasing operating costs and reducing R&D. (3) However, those adverse effects can be suppressed when a region's degree of marketization is high and industry competition is fierce. Although our results show that the LCCP policy indeed brings more significant economic costs, those economic distortions can weaken through market-based reforms and improved market competition.

TiO2 nanoparticles negatively impact the bioavailability and antioxidant activity of tea polyphenols.

This study was to investigate the influence of TiO2 nanoparticles (NPs) on the stability, bioavailability, and antioxidant activity of co-ingested tea polyphenols extract using an in vitro digestion model. The tea polyphenol contents decreased significantly after addition of 0.5 % (w/w) TiO2 NPs. The gallocatechin gallate level decreased the most, changing from 101.9 to 27.2 µg/mL (about 73.3%). The TiO2 NPs also reduced the bioavailability of the tea polyphenols in a dose-dependent manner, which was ascribed to the formation of large polyphenol-TiO2 NP complex aggregates that could not pass through the pores in the dialysis tube used to simulate the gut wall. Additionally, the TiO2 NPs decreased the antioxidant activity of the tea polyphenols within the simulated gastrointestinal tract. In summary, our results show that high levels of TiO2 NPs (but within the current legal limits in many countries) may negatively impact the bioavailability and bioactivity of polyphenols in foods.

Polysaccharide conjugates from Chin brick tea (Camellia sinensis) improve the physicochemical stability and bioaccessibility of ß-carotene in oil-in-water nanoemulsions.

A natural antioxidant emulsifier, tea polysaccharide conjugate (TPC), was isolated from Chin brick tea. The impact of TPC on ß-carotene stability and bioaccessibility in oil-in-water nanoemulsions was assessed. TPC exhibited strong antioxidant activity and could be used to fabricate stable nanoemulsions (d < 140 nm). The extent of lipid digestion was considerably lower for lipid droplets coated by TPC (68%) than Tween 80 (94%) or whey protein isolate (WPI) (89%), probably because TPC formed interfacial layers that hindered the access of lipases to lipids. The chemical stability of ß-carotene in TPC-nanoemulsions was markedly higher than in those formulated with Tween 80 or WPI due to the high antioxidant activity of TPC. The bioaccessibility of ß-carotene (20-30%) was independent of emulsifier type. TPC from Chin brick tea can therefore be used as a dual-purpose functional ingredient in emulsified foods.

Impact of Polyphenol Interactions with Titanium Dioxide Nanoparticles on Their Bioavailability and Antioxidant Activity.

Titanium dioxide is widely utilized as a pigment in the food industry to enhance the whiteness or brightness of foods and beverages. The powdered forms of titanium dioxide used as food ingredients contain a substantial fraction of nanoparticles (d < 100 nm), which may have adverse effects on human health. This is a model study that investigated the molecular interactions between TiO2 nanoparticles and selected polyphenols, as well as their influence on the in vitro bioavailability and antioxidant activity of the polyphenols. Our results showed that the chemical structure of polyphenols significantly influenced their binding affinity to TiO2 nanoparticle surfaces, with those possessing vicinal trihydroxy groups having the highest binding affinities. The presence of TiO2 nanoparticles was shown to reduce the bioavailability of polyphenols using an in vitro digestion model. This effect was mainly ascribed to the formation of large TiO2 nanoparticle-polyphenol complex agglomerates that could not pass through the pores in the dialysis tube used to simulate the epithelium layer. Additionally, the binding of polyphenols to the surfaces of TiO2 nanoparticles reduced their antioxidant activity. This study provides valuable insights into the impact of inorganic nanoparticles on the bioavailability and bioactivity of polyphenols.