Gut microbiota shifts in spaceflight: a case study evidence and countermeasures for microbial homeostasis.

This study has conducted to determine the concentration levels of furan, furfural and 2-methylfuran in the six commercially available soy sauce varieties by an optimized Gas Chromatography Tripple Quadruple Mass Spectrometry. The extraction of analytes was performed by solid phase microextraction using 50/30 µm CAR/DVB/PDMS fibre in 25 min with 20% NaCl concentration under 35 °C and separation was performed on HP5-MS column. Different concentration levels of furan, furfural and 2-methylfuran were determined which differed significantly at p < 0.05. A total of four metal ions (Iron sulphate, magnesium sulphate, calcium sulphate and sodium sulfite), ascorbic acid and natural antioxidants (epicatechin, epigalactocatechin and kempferol) were added in the soy sauce samples by simulating sterilization conditions. A higher reduction level was given by calcium sulphate with reduction upto 90.68%, 89.07% and 65.42% for furan, furfural and 2-methylfuran, respectively, in comparison with other metal ions. Since iron sulphate and ascorbic acid have triggered formation of furanoic compounds upto high levels instead of reduction. Moreover, from natural antioxidants, epicatechin and kemferol have provided more reduction levels around 89.66%, 90.14% and 78.75% for furan, furfural and 2-methylfuran, respectively by sterilization with catichen and 88.80%, 90.36% and 84.29% for furan, furfural and 2-methylfuran, respectively by sterilization with kempferol than epigalactocatechin. Moreover, this method was also validated in terms of sensitivity, recovery, relative standard deviation and LOD and LOQ for all analytes.