Hot air-assisted radio frequency (HA-RF) has great advantages in roasting of nuts compared to traditional roasting methods.To investigate the changes in antioxidant properties and pathogenic microorganisms of almond kernels during HA-RF roasting, almond kernels were roasted by three intensities, including HA-RF1 (target temperature 130 ℃, heating time 11 min, holding time 4 min), HA-RF2 (target temperature 155 ℃, heating time 15 min), and HA-RF3 (target temperature 155 ℃, heating time 15 min, holding time 19 min).Color, antioxidant properties, and the population of Enterococcus faecalis were determined before and after HA-RF treatments, where E.faecalis was used as a surrogate for Salmonella.After HA-RF roasting, ABTS cationic radical scavenging capacity and Fe3+ reduction capacity of almond kernels were increased, and overall antioxidant properties were improved.When the initial water activity (aw) of almond kernels was 0.65, hot air (HA) roasting (155 ℃, 20 min) only reduced E.faecalis by about 2 lg CFU/g.In contrast, HA-RF1 reduced E.faecalis by more than 4 lg CFU/g, and HA-RF3 exhibited the most effective killing effect, reducing it by 7 lg CFU/g.HA-RF roasting enhanced antioxidant properties of almond kernels and effectively pasteurized pathogens, which ensured superior microbiological safety compared to traditional HA roasting.This study provided basis for application of HA-RF in almond kernels.
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