Study on Mass Transfer and Physicochemical Properties of Avocado During Osmotic Dehydration

A previous study found that mass transfer occurring during the osmotic dehydration (OD) process. This phenomena is possible causing modification in physicochemical properties; therefore, understanding the OD effect on quality attributes is important. This research aimed to study the impact of sucrose concentration and immersion time on the kinetics of mass transfer and the physicochemical properties of avocado (Persea americana var. Miki) during the OD process. The samples were immersed in a sucrose solution (45, 55 and 65 ° Brix) for up to 300 min, then the mass transfer parameter and physicochemical properties were evaluated. The results showed that the highest rate of water removal (WR) was –0.037 g.g–1.h–1 using the 55 ° Brix solution, which also led to an increase in the soluble solid gain (SSG) value to 0.0126 g.g–1.h–1, while the highest WR/SSG ratio was obtained after 180 min of immersion using 65 ° Brix (2.451). A 2nd-order polynomial model accurately describes avocado mass transfer kinetics and their relationship to physicochemical properties. The model showed the best adjustment for WR, SSG, and weight loss (WL), as pointed out by R2 = 0.9671, 0.8968 and 0.9573, respectively. WR has a negative effect on firmness (R2 = 0.9278), vitamin C (R2 = 0.9349), and total fat (R2 = 0.8954). The uptake of sucrose correlated with decrease of vitamin C (R2 = 0.9391), whereas WL also affected the loss of total fat (R2 = 0.8288). The OD process modified the chroma of the avocado by reducing lightness, increasing greenness and yellowness, and yet protecting the flesh from the browning effect. Overall, this study provides insights into the relationship between mass transfer and physicochemical properties, and it is useful to predict the final condition of the osmo-avocado before subsequent processes. HIGHLIGHTS Immersing the avocado in a 55 ° Brix solution resulted in the highest rate of water removal (WR) and soluble solid gain (SSG). The highest ratio of WR and soluble solid gain (WR/SSG) was obtained at 180 min of immersion using a 65 ° Brix solution. The 2nd-order polynomial model fits the mass transfer parameters (WR, SSG, and weight loss/WL). WR contributed to a softened texture, color contrast, degradation of vitamin C, and total fat content. The combination of mass transfer and physicochemical property models is useful for designing the OD process and predicting the final condition of osmo-avocado. GRAPHICAL ABSTRACT