Abstract: The purpose of this study was to investigate the effect of heat treatment on the stability and protein structure of hemp seed milk. The stability was monitored by the nitrogen solubility index (NSI), centrifugal precipitation rate, emulsification characteristics, emulsion surface potential and particle size. Fourier transform infrared (FTIR) spectroscopy was used to characterize the secondary structure of hemp seed milk proteins. The results showed that with the increase in heat treatment temperature (55–95 ℃), the NSI decreased from 58.55% to 39.81%, the centrifugal precipitation rate increased from 16.58% to 34%, and the average particle size increased from 192.2 nm to 304.6 nm. The results of FTIR analysis showed that the secondary structures of hemp seed milk proteins changed with the increase in heat treatment temperature. The relative content of α-helix decreased from 28.57% to 23.70%, while the relative content of random coil increased from 21.13% to 25.41%. The maximum absolute value of zeta potential of 20.57 mV was observed when hemp seed milk was treated at 65 ℃, accompanied by the best stability and the highest emulsification activity and emulsification stability with emulsifying activity index (EAI) of 0.357 m2/g and emulsion stability index (ESI) of 43.74%. This study will provide a theoretical basis for the processing and application of hemp seed milk.

Key words: hemp seed milk; heat treatment; stability; secondary structure