Synergistic effect of microwave heating and hydrothermal treatment on cyanogenic glycosides and bioactive compounds of plum (Prunus domestica L.) kernels: An analytical approach

Abstract

The effects of microwave heating (450 W for 6 min), hydrothermal treatment (6, 9, and 12 h at 45 °C) and their combination on compositional characteristics, cyanogenic glycosides, color, and bioactive compounds of plum kernels have been studied. The conditions examined caused a significant reduction of 37.81, 72.17, 84.41, 91.24 and 98.02% in cyanogenic glycosides of differently treated plum kernels. Total phenolic and total flavonoid compounds of plum kernels showed hydrothermal time-dependent duration decline. The larger shifts in FT-IR spectra near 1157 cm-¹ provided valuable insights on the reduction of cyanogenic glycosides during combined treatments. The variation of color attributes (L*, a*, b*), during combined treatments indicates a more reddish tonality of plum kernel samples. The combined effect of hydrothermal (12 h at 45 °C) and microwave heating (450 W for 6 min) proved to be an effective tool for neutralizing the toxic effect of cyanogenic glycosides, opening up possibilities for its use in food industries.

Keywords: Bioactive compounds; Cyanogenic glycosides; Detoxification; FT-IR; Plum kernels.

Graphical abstract

Fig. 1

(a) Total phenolic compounds (TPC) and (b) total flavonoid compounds (TFC) of N: Native plum kernel sample; A1: Plum kernel sample microwaved at 450 W for 6 min; A2: Plum kernel sample soaked for 9 h at 45 °C; A3: Plum kernel sample soaked for 6 h at 45 °C and microwaved at 450 W for 6 min; A4: Plum kernel sample soaked for 9 h at 45 °C and microwaved at 450 W for 6 min and A5: Plum kernel sample soaked for 12 h at 45 °C and microwaved at 450 W for 6 min.

Fig. 2

Cyanogenic glycosides of N: Native plum kernel sample; A1: Plum kernel sample microwaved at 450 W for 6 min; A2: Plum kernel sample soaked for 9 h at 45 °C; A3: Plum kernel sample soaked for 6 h at 45 °C and microwaved at 450 W for 6 min; A4: Plum kernel sample soaked for 9 h at 45 °C and microwaved at 450 W for 6 min and A5: Plum kernel sample soaked for 12 h at 45 °C and microwaved at 450 W for 6 min.

Fig. 3

FT-IR Spectra of N: Native plum kernel sample; A1: Plum kernel sample microwaved at 450 W for 6 min; A2: Plum kernel sample soaked for 9 h at 45 °C; A3: Plum kernel sample soaked for 6 h at 45 °C and microwaved at 450 W for 6 min; A4: Plum kernel sample soaked for 9 h at 45 °C and microwaved at 450 W for 6 min and A5: Plum kernel sample soaked for 12 h at 45 °C and microwaved at 450 W for 6 min.