Impact of different water treatments of peanuts during the roasting process on the flavour profile and chemical qualities of the peanut oil

Abstract The objective of this study was to investigate the impact of different water treatments with different water contents in peanut kernels on the flavour profile and chemical qualities of roasted peanut oil (RPO). Based on relative odour activity value, the key aroma-active compounds of steamed peanut oil (SPO) and RPO were selected as the evaluation objects. An increase in water content in peanut kernels from 4.20% to 52.55% significantly enhances the intensity of sweet and steamed flavour attributes of RPOs. The enhancement observed can be attributed to a 7.26-fold increase in the content of benzeneacetaldehyde and an 8.03-fold decrease in 6 key aroma-active pyrazines. These 6 pyrazines are: 2,6-dimethylpyrazine, trimethylpyrazine, 2,3-dimethylpyrazine, methylpyrazine, 2-ethyl-5-methylpyrazine, and 2-ethyl-6-methylpyrazine. Model experiments verified the effect of water on the formation of pyrazines and Strecker aldehydes. From the quality point of view, an elevation in water content leads to a reduction in both acid value and phospholipid content. However, excessive water content can decrease the stability of RPOs. Thus, taking consideration of achieving mellow flavour characteristics and a better chemical quality, an optimal water content of 22.05% in peanut kernels is recommended. This finding offers a potential approach for optimising the flavour characteristics of RPOs through targeted adjustment of peanut kernel’s initial water content.