Effect of antibrowning agents on browning and intermediate formation in the glucose-glutamic acid model

In this study, the inhibitory effects of antibrowning agents on browning and the formation of intermediates such as 3-deoxyglucosone (3-DG) and hydroxymethylfurfural (HMF) were evaluated with a glucose-glutamic acid model for soybean paste. The initial antibrowning capacity was measured in the following order: pentasodium tripolyphosphate < citric acid and oxalic acid < cysteine and glutathione < sodium sulfite. Our data showed that antibrowning agents, such as pentasodium tripolyphosphate, citric acid, and oxalic acid, were maintained antibrowning capacities during storage at both 4 and 30 °C, respectively. However, both cysteine and glutathione was reduced with storage time, especially in the air. A marked effect of nitrogen treatment was noted for 3 of the antibrowning agents after storage in air at 30 °C in the following order: sodium sulfite < cysteine < glutathione. The formation ratio of 3-DG and HMF was higher after storage at 30 °C than at 4 °C. These compounds were produced most abundantly in the presence of sodium sulfite, and the yields were not related significantly to the degree of browning. Citric acid and oxalic acid were identified as the most effective in inhibitors of browning and intermediates, even during storage in air at 30 °C.