RESUMO
Wild bitter gourd (Momordica charantia L. var. abbreviata S.) is a kind of Chinese herbal medicine and is also a vegetable and fruit that people eat daily. Wild bitter gourd has many bioactive components, such as saponin, polysaccharide, and protein, and the extract is used to adjust blood sugar in patients with diabetes. The objective of this study was to investigate simultaneous hot air-assisted radio frequency (HARF) drying and pasteurization for bitter gourd extract, and then to evaluate its effects on blood sugar of type II diabetic mice. The results showed that the solid-liquid ratio of the wild bitter gourd powder to water was 1:10 and it was extracted using focused ultrasonic extraction (FUE) for only 10 min with 70 °C water. Then, 1 kg of concentrated bitter gourd extract was mixed with soybean fiber powder at a ratio of 2:1.1. It was dried by HARF, and the temperature of the sample could reach above 80 °C in only 12 min to simultaneously reduce moisture content (wet basis) from 58% to 15% and achieve a pasteurization effect to significantly reduce the total bacterial and mold counts. Type II diabetic mice induced by nicotinamide and streptozocin (STZ) for two weeks and then were fed four-week feeds containing 5% RF-dried wild gourd extract did not raise fasting blood glucose. Therefore, the dried powder of wild bitter gourd extracts by HARF drying had a hypoglycemic effect.
RESUMO
Nitroaromatic compounds (NACs) are an important class of nitrogen-containing compounds in fine particles. The investigation of characteristics and seasonal variation of NACs in PM2.5 increases our knowledge about nitrogen-containing compounds and contributes to the scientific basis in formulating reduction policies of NOx in urban areas. In this study, we analyzed the chemical composition of PM2.5 samples collected from March 2018 to February 2019 in an urban location in Shanghai. A total of 2439-3695 organic molecular formulas were detected using UPLC-Orbitrap MS. Nine NACs were quantified using an internal standard method. In spring, ρ(NACs) ranged from 3.12 to 16.76 ng·m-3, and the average concentration was 9.31 ng·m-3. In summer, it ranged from 1.05 to 9.70 ng·m-3, and the average value was 4.16 ng·m-3. In autumn, it ranged from 2.87 to 36.27 ng·m-3, and its average was 9.84 ng·m-3. In winter, it ranged from 4.83 to 56.23 ng·m-3, and the average was 22.37 ng·m-3. 4-Nitrophenol accounted for more than 25% of the quantified NACs in different seasons. In summer, the concentration of 5-nitrosalicylic acid accounted for 36%, but it decreased to 19% in winter. NACs in summer mainly originated from secondary formation, as evidenced by their clear correlation with the oxidant level, whereas biomass burning became the main source of NACs in winter.