Effect of osmotic dehydration on qualitative and nutritional characteristics and kinetics of microwave drying of Iranian Quince slices

Abstract

Iranian quince is a nutritious fruit with antioxidants that protect against diseases. Due to its tough texture, it’s fresh form is rarely consumed. This study investigates the impact of osmotic dehydration (OD) on the quality of microwave-dried quince slices. The OD pretreatment was performed in a sucrose solution (30, 50, and 70◦Bx) and immersed at times of 10, 20, and 30min. Microwave power is also regarded as an independent variable at three levels of 150, 300, and 400 W. The OD pretreatment not only decreased the drying time by up to 32 % but also resulted in dried slices exhibiting greater antioxidant activity, total phenolic content, and vitamin C compared to fresh samples. For instance vitamin C increasing by 66 % in the control sample dried at 180 W, while OD achieved an impressive 87 % increase. The OD pretreatment decreased the drying time by up to 32 %. The dried slices pretreated with OD had greater antioxidant activity, total phenolic content, and vitamin C than fresh samples. Vitamin C increased by 66 % in the control sample dried at 180 W, while OD achieved an 87 % increase. The OD conditions had no significant effect (P > 0.05) on total phenolic content and antioxidant activity, but a significant effect on vitamin C (P ≤ 0.05). Additionally, Microwave power significantly influenced all color parameters of the samples. The least color change (ΔE) occurred in samples dried at 450 W microwave power, 50°Bx osmotic concentration, and 20 min immersion. Midilli et al.’s model was identified as the most effective for describing the microwave drying process. Besides, a comprehensive comparison of recent studies on the use of OD in fruit drying and the information they provide is presented. Consequently, optimal results were obtained at specific conditions, highlighting the effectiveness of the OD pretreatment in enhancing the microwave drying process of Iranian quince slices.

Keywords

• Antioxidant activity
• Color change
• Drying kinetics
• Drying rate
• Total phenolic content
• Vitamin C