Quality evaluation of Alpinia oxyphylla after Aspergillus flavus infection for storage conditions optimization

In the storage of Alpinia oxyphylla, growth of mildew (especially toxic fungi, such as Aspergillus flavus) is a potential safety risk. Few reports have investigated how A. oxyphylla storage conditions impact mold growth or how mold growth impacts the bioactive components of A. oxyphylla. In this study, sterilized A. oxyphylla samples were contaminated by artificial inoculation of A. flavus spores. The main chemical components and aflatoxin levels in the infected A. oxyphylla samples were characterized. Central composite design-response surface methodology was used to study the effects of different temperature and humidity of storage conditions on the fungal growth in A. oxyphylla and accumulation of aflatoxins. The results showed that aflatoxins levels can be minimized by storing samples at temperatures below 25 °C and with humidity less than 85%. Additionally, we found that the yield and composition of volatile oil in A. oxyphylla exhibited small changes due to mold growth. However, polysaccharide content reduced remarkably. Temperatures below 25 °C and humidity below 85% were the best storage conditions to preventing A. oxyphylla from becoming moldy. Our results provide the theoretical basis for future studies the effects of storage conditions and mold growth on the quality and safety of traditional Chinese medicines (TCMs). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13568-017-0450-x) contains supplementary material, which is available to authorized users.