The influence of soaking pretreatment on the mouthfeel and crispiness of fried broad beans (Vicia faba L.) and its mechanism

Abstract

Consumers dislike fried broad beans with hard core due to inadequate crispiness, so an alternative approach with its mechanism is proposed in the present work. Results showed that the optimum soaking procedure was that 5 h in water followed by 3 h in 2 % NaHCO₃. For water soaking process, water absorption, starch gelatinization and protein structure played antagonistic roles. As time lengthened, increased water uniformity and starch gelatinization (11.87 % to 92.36 %) induced structure swelling which was beneficial for later crispiness formation, but β-sheet dropped to 41.50 % which indicated the collapse of structure due to excessive soaking. NaHCO₃ enhanced crispiness through increased multilayer adsorbed water (17.03 % to 24.62 %) which occupied pores at room temperature and fled at fried temperature. It also promoted short-range order of starch (R_1047/1022 from 0.45 to 0.82) and the increase of β-sheet and α-helix in protein, contributing to a more stable internal network with uniform pore distribution.