Authenticating apple cider vinegar’s home remedy claims: antibacterial,antifungal, antiviral properties and cytotoxicity aspect

These are the days when one would go online first seeking home remedies before seeing a doctor. Apple cider vinegar (ACV) is one such popular yet scientifically under-validated remedy. Our results prove the unequivocal antimicrobial activity of ACV to be true at full strength concentrations. However, the activity cannot be generalised because although strong antibacterial activity was observed at 25% concentrations, in terms of antifungal activity, yeasts, especially Candida were found to be less susceptible. The antimicrobial/antioxidant properties are ascertained to the total phenolic contents of ACV, as confirmed by our characterisation of the bioactive compounds and antioxidant activity. When checking for its cytotoxicity, ACV exhibited toxicity even at concentrations as low as 0.7%. These results indicate that there is no question of generalising the idea of ACV usage, instead more in vitro and in vivo validations are necessary in order to precisely weigh the pros and cons of ACV.     

Production of bacterial cellulose by Gluconacetobacter sp. RKY5 isolated from persimmon vinegar

The optimum fermentation medium for the production of bacterial cellulose (BC) by a newly isolated Gluconacetobacter sp. RKY5 was investigated. The optimized medium composition for cellulose production was determined to be 15 g/L glycerol, 8 g/L yeast extract, 3 g/L K₂HPO₄, and 3 g/L acetic acid. Under these optimized culture medium, Gluconacetobacter sp. RKY5 produced 5.63 g/L of BC after 144 h of shaken culture, although 4.59 g/L of BC was produced after 144 h of static culture. The amount of BC produced by Gluconacetobacter sp. RKY5 was more than 2 times in the optimized medium found in this study than in a standard Hestrin and Shramm medium, which was generally used for the cultivation of BC-producing organisms.     

Butyltin compounds in vinegar collected in Beijing: Species distribution and source investigation

Forty-eight vinegar samples including white vinegar,rice vinegar and mature vinegar were collected from several markets in Beijing.Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate.Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 μg Sn L 1.The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar.Vinegar samples with relatively high butyltin concentration(>1.5 μg Sn L 1) were those stored in plastic bags,indicating that the plastic bag was one of the possible sources of butyltin contamination.This was further confirmed by the leaching experiments of three selected plastic bags,and monobutyltin was detected in the leaching solvents.According to the estimation,the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w.,much lower than the Tolerable Daily Intake(TDI) of 100 ng Sn/kg b.w.set by the European Food Safety Authority(EFSA).     

Direct determination of mercury in white vinegar by matrix assisted photochemical vapor generation atomic fluorescence spectrometry detection

This paper proposes the use of photochemical vapor generation with acetic acid as sample introduction for the direct determination of ultra-trace mercury in white vinegars by atomic fluorescence spectrometry. Under ultraviolet irradiation, the sample matrix (acetic acid) can reduce mercury ion to atomic mercury Hg⁰, which is swept by argon gas into an atomic fluorescence spectrometer for subsequent analytical measurements. The effects of several factors such as the concentration of acetic acid, irradiation time, the flow rate of the carrier gas and matrix effects were discussed and optimized to give detection limits of 0.08 ng mL⁻¹ for mercury. Using the experimental conditions established during the optimization (3% v/v acetic acid, 30 s irradiation time and 20 W mercury lamp), the precision levels, expressed as relative standard deviation, were 4.6% (one day) and 7.8% (inter-day) for mercury (n = 9). Addition/recovery tests for evaluation of the accuracy were in the range of 92–98% for mercury. The method was also validated by analysis of vinegar samples without detectable amount of Hg spiked with aqueous standard reference materials (GBW(E) 080392 and GBW(E) 080393). The results were also compared with those obtained by acid digestion procedure and determination of mercury by ICP-MS. There was no significant difference between the results obtained by the two methods based on a t-test (at 95% confidence level).     

Economic analysis of biobutanol recovery from the acetone-butanol-ethanol fermentation using molasses

Commercial production of biobutanol via acetone-butanol-ethanol (ABE) fermentation is challenged by the energy-intensive recovery of biobutanol from inherently diluted fermentation broth. Towards the solution of this problem, four combinations (scenarios) of separation techniques such as distillation, gas stripping (GS), liquid-liquid extraction (LLE), and pervaporation (PV) are investigated for the minimum unitary production cost of biobutanol. Cost components for the installation and operation of the plant are estimated using Matlab software and method given by Peters and Timmerhaus. Production costs with significant variables viz. biobutanol yield, price of molasses, and fermenter volume are individually estimated. Gas stripping followed by distillation is found as the most economical scenario with a unitary production cost of INR 74/kg. The optimum values of yield and fermenter volume are found as 0.4 kg ABE/kg sugars and 100 m³, respectively. The optimization of three major variables around the baseline values provides nearly 10% reductions in the cost with present fermentation technology. This economic analysis of biobutanol recovery certainly contributes to the commercial production of biobutanol from renewable raw materials. The economic feasibility of biodiesel production may offer better environment to the mankind.