Effects of liquid smoke infusion on osmotic dehydration kinetics and microstructural characteristics of apple cubes

Abstract

The influence of the addition of Refined Liquid Smoke (RLS) (1% w/w) to a sugar-based Osmotic Solution (OS) (42 °Brix) on the osmotic dehydration (OD) kinetics and microstructure of apple cubes was evaluated. Cubes of 10 mm were cut from peeled apples and subjected to OD at the incubation temperature of 50 °C and over a range of OD duration (5–240 min). Influence of addition of RLS was evaluated for selected OD kinetic variables: solid gain (SG), water loss (WL), dry matter (DM), soluble solid content (SSC), and moisture content. Results showed that addition of RLS significantly increased SG, DM, and SSC in apple cubes compared to pure sugar solution-based OD. As a result of RLS addition, the sugar concentration in apple cubes increased from 9.90 °Brix to 33.8 °Brix whereas it was 31.02 °Brix for the pure sugar solution-based OD. Further kinetic analysis showed that the effective diffusion coefficient for SG was same (4.40 × 10−10 m2/s) irrespective of the addition of RLS; however, the effective diffusion coefficients for WL were different (2.94 × 10−10 m2/s for pure sugar-based OD and 4.40 × 10−10 m2/s for RLS-added OD). Microstructural visualization of the dried apples revealed that the addition of the RLS might have prevented the collapse of cell wall up to the first hour of OD.