Antibacterial Characteristics and Stability of Fractionated Extracts from Peanut Hull

In this paper,the effective antibacterial components in peanut hull were extracted by solvent extraction method. The antibacterial activity of different extracts on common spoilage bacteria and pathogenic bacteria in food was studied by filter paper method,and the influence of pH,temperature,ultraviolet radiation and metal ions on its stability was explored. The results showed that the peanut hull fraction extract had certain inhibitory activity on the tested bacterias,and the ethyl acetate extract had the strongest inhibitory effect on Staphylococcus aureus,and the minimum inhibitory concentration(MIC)against Staphylococcus aureus and Escherichia coli were 31.25 and 62.5 mg/mL,respectively. The stability experiment showed that the antibacterial activity of the ethyl acetate extract of peanut hull decreased significantly at 7 < pH < 10;after 20~80℃ treatment,the antibacterial activity was stable,but when the treatment was too high or too low(0,100℃),the antibacterial activity decreased. With the increase of UV irradiation time,the antibacterial activity decreased. The antibacterial effect of metal ions on the ethyl acetate extract of peanut shell was different,Cu²⁺,Fe²⁺ and Al³⁺ could enhance its inhibition,Mg²⁺,K⁺,Mn²⁺ could reduce its antibacterial effect. This experiment can provide a basis for the development of peanut shell extract as a natural preservative for food.