Physicochemical properties, structural transformation, and relaxation time in strength analysis for honey powder models

Abstract Present study developed a strength analysis for relaxation time ( τ ) in characterizing physicochemical properties and structural transformation of freeze-dried honey/whey protein isolate (H/WPI) and honey/maltodextrin (H/MD) models based on water sorption, time-dependent crystallization, glass transition, and α-relaxation at various water activities (0.11 a w to 0.76 a w ) and 25 °C. Water sorption data of two models explained WPI was a more effectiveness drying stabilizer than MD as H/WPI model owned higher monolayer water content. Crystallization was observed in prepared models with drying-aids content below 50% of mass ratios at water activity above 0.44 a w and 25 °C, whereas the extent of crystallization and structural collapse were inhibited by WPI and MD addition based on sorption isotherms. Glass transition temperature, α-relaxation temperature, and τ for two models were composition-dependent and altered by water, WPI, and MD at water activity below 0.44 a w . According to strength analysis of τ , the S for H/WPI and H/MD models was affected by drying-aids and could give a quantitative measure to estimate compositional effects on τ . Moreover, a S -involved state diagram was established to determine the critical parameters (water content and S ) for controlling structural transformation of honey powder models during production and storage, i.e., collapse and stickiness.