Abstract: As a new non-thermal food processing technology, high hydrostatic pressure (HHP) has many advantages, such as less damage to the nutritional and sensory quality of foods. To study the effect of different food processing methods on the functional properties of buckwheat protein (BWP), the solubility, foaming and emulsifying properties of BWP were determined along with its carbonyl content, sulfhydryl content, surface hydrophobicity and Fourier transform infrared spectroscopy (FTIR) analysis after being treated by HHP or heat treatment (HT). The results showed that with the increase in HHP treatment pressure, the carbonyl content and surface hydrophobicity of BWP increased significantly (P < 0.05), while the sulfhydryl content decreased significantly (P < 0.05); the emulsifying and foaming capacities reached the maximum values (67.3 m2/g and 91.5%) at 500 MPa, which were 33.0% and 16.1%, 61.5% and 52.8% higher than those of the control group (without HHP treatment) and the HT group, respectively. The results of FTIR showed that the contents of α-helix and β-fold decreased, while the contents of β-turn and random coil increased after HHP treatment. Moreover, obvious correlations were found between the solubility, emulsifying capacity, foaming capacity, carbonyl content and sulphydryl content of BWP. Notably, the emulsifying capacity was significantly positively correlated with foaming capacity and surface hydrophobicity (P < 0.01), but significantly negatively correlated with sulfhydryl content (P < 0.01). It can be seen that HHP treatment can change the functional properties of BWP. This study provides a theoretical and experimental basis for further studies on the application of BWP in functional foods.

Key words: high hydrostatic pressure treatment; heat treatment; buckwheat protein; functional properties