Di Sun,Jin Mao,Zhijian Wang,Hui Li,Liangxiao Zhang,Wen Zhang,Qi Zhang,Peiwu Li
Peanut is an important resource of edible oil and digestible protein in daily life, which is rich in the nutriments and antioxidants such as vitamins, minerals and polyphenols. However, peanut is susceptible to the contamination of Aspergillus flavus ( A. flavus ), which can produce highly carcinogenic toxins that brings serious threats to human health and food safety. Exploring green and effective methods to control A. flavus is meaningful. Herein, a green and economical way to control A. flavus on peanuts was demonstrated. It was found that the growth of A. flavus hyphae and germination of its spores could be inhibited in the presence of α-Fe 2 O 3 nanorods under sunlight irradiation according to the agar diffusion method , flat colony counting method and fluorescence-based live/dead test. The diameter of inhibition zone was 22.3 ± 0.2 mm and the inhibition rate of spores germination was about 60 ± 5%, when the concentration of α-Fe 2 O 3 was 10 mg/mL for 7 h sunlight irradiation. Most important, α-Fe 2 O 3 showed the photocatalytic inhibition of A. flavus on peanuts under sunlight irradiation with the inhibition rate of about 90 ± 5%, and the production of aflatoxin B 1 and aflatoxin B 2 were reduced by 90 ± 2% and 70 ± 3%, respectively. By comparing the fat contents, protein contents, acid value, peroxide value and antioxidative compositions of peanuts, it was found that there was no obvious effect on the quality of peanuts after inhibition treatment. The findings provide a green, safe and economical strategy to control A. flavus on peanuts, which may be as a promising way to be used in food and agro-food preservation.
Wang Yun,Tan Hongjie,Sang Lexian,Xie Yunying,Jia Fuchao,Zhou Tong,Yin Guangchao,Sun Fazhe,Wang Xiaomei
An optimized acetone gas sensor based on Ti 3 C 2 / α -Fe 2 O 3 (TF) composite materials was synthesized using microwave and etching methods. The structures, morphology and composition of the TF composites were characterized via XRD, XPS, SEM and TEM. The crystal of α -Fe 2 O 3 porous nanorods is hexagonal, and the α -Fe 2 O 3 nanoclusters formed from α -Fe 2 O 3 nanorods were adhered adequately on the lamellar Ti 3 C 2 MXene in the TF composite. The specific surface area and surface defects of the TF composites increased compared with pure α -Fe 2 O 3 nanocluster material, thus exposing a large number of gas adsorption sites. Furthermore, the excellent electrical conductivity and high free charges transfer ability of Ti 3 C 2 MXene provided more electrons for the gas-sensitive reaction and enhanced the transmission capacity of gas-sensitive reaction electrical signal, respectively. The Schottky barriers were formed at the interface of α -Fe 2 O 3 and Ti 3 C 2 MXene increasing the resistance of TF gas sensor in air, which is beneficial to the response of TF gas sensor. So, the gas-sensitive performance of TF gas sensor to acetone was greatly improved. The response of TF gas sensor to 100 ppm acetone was up to 23.38, which was nearly 2.3 times higher than pure α -Fe 2 O 3 gas sensor. The lower detection limit of TF gas sensor could be as low as 1 ppm. In addition, the TF gas sensor had excellent selectivity, long-term repeatability and stability for acetone.