Ren Wang

Ozonolysis pretreatment of maize stover: the interactive effect of sample particle size and moisture on ozonolysis process.

Maize stover was ozonolyzed to improve the enzymatic digestibility. The interactive effect of sample particle size and moisture content on ozonolysis was studied. After ozonolysis, both lignin and xylan decreased while cellulose was only slightly affected in all experiments. It was also found that the smaller particle size is better for ozonolysis. The similar water activity of the different optimum moisture contents for ozonolysis reveals that the free and bound water ratio is a key factor of ozonolysis. The best result of ozonolysis was obtained at the mesh of -300 and the moisture of 60%, where up to 75% lignin was removed. The glucose yield after enzymatic hydrolysis increased from 18.5% to 80%. Water washing had low impact on glucose yield (less than 10% increases), but significantly reduced xylose yield (up to 42% decreases). The result indicates that ozonolysis leads to xylan solubilization.

Detoxification of aflatoxin in corn flour by ozone

BACKGROUNDnCorn, which is one of most important agricultural products worldwide, is prone to pollution by aflatoxins (AFs) in many areas, thus seriously jeopardizing human health and threatening economic growth. This study evaluated the effects of ozone on the detoxification of AFs in corn flour (CF) and the moisture content (MC) thereof.nnnRESULTSnThe detoxifying effects of ozone on CF became more obvious as the ozone concentration and exposure time increased. After CF was treated with 75 mg L(-1) ozone for 60 min, the contents of AFB1 , AFG1 and AFB2 decreased from 53.60, 12.08 and 2.42 µg kg(-1) to 11.38, 3.37 and 0.71 µg kg(-1) , respectively, which are lower than the maximum limits of AFB1 , AFG1 , AFB2 and total AFs (20 µg kg(-1) ) for CF regulated by the Chinese government. Ozonation significantly affected the MC of CF, and ozone at a higher concentration decreased the MC more drastically. After CF was exposed to 15, 30, 45 and 75 mg L(-1) ozone for 60 min, the MC of CF decreased from 17.4% to below 15%, fulfilling the long-period storage requirements for CF.nnnCONCLUSIONnOzone is potentially applicable in effectively degrading the AFs in CF and in greatly decreasing the MC of CF.

Analyses by UPLC Q-TOF MS of products of aflatoxin B1 after ozone treatment

Analysing the products of ozone-treated aflatoxin B1 (AFB1) is essential in order to study the practical use of ozone treatment. In this paper, the products of AFB1 were investigated using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC Q-TOF MS). The products were well separated using UPLC, and the accurate masses of all the products were determined using Q-TOF MS. Finally, the possible pathways of fragmentation ion generation from the products of AFB1 and the structures of four products were proposed. From the view of the proposed structures of products, the C8-C9 double bond in the terminal furan ring was destroyed. According to the structure–activity relationship, the toxicity of products was significantly reduced compared with that of AFB1. The result indicated that ozone was an effective agent for degrading AFB1, and UPLC Q-TOF MS was a useful analytical tool for proposing and identifying a series of unknown products.