Chunfang Song1,2, Xiaotong Ma1, Zhenfeng Li1, Tao Wu1,2, Gs Vijaya Raghavan3, Haiying Chen1,2. 1. Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, School of Mechanical Engineering, Jiangnan University, Wuxi, Jiangsu, P. R. China. 2. Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Technology, Beijing Technology and Business University (BTBU), Beijing, P.R.China. 3. Department of Biosource Engineering, McGill University, Ste.-Anne- de-Bellevue, QC, Canada.
Abstract
BACKGROUND: The combination of sugar osmotic dehydration and microwave vacuum drying is an effective method for the dehydration of blackberries, the retention of their antioxidant properties, and the extension of their shelf life. Mass transfer during the osmotic dehydration of blackberries in sugar solution was investigated together with its influence on microwave vacuum drying characteristics, and the retention rate of anthocyanins in dried frozen blackberries. RESULTS: The concentrations of the osmotic solutions that were tested contained 40%, 50%, and 60% sugar, and the osmotic solution temperatures were 30 °C, 40 °C, and 50 °C. The solution-to-blackberry mass ratio was 10:1 (w/w) and the process duration varied from 0 to 5 h. A two-parameter mathematical model was used to describe mass transfer in the osmotic dehydration of blackberry samples and estimate moisture loss and solid gain in the final equilibrium. The results showed that the dehydration rate and solid gain rate of the blackberries increased with an increase in osmotic concentration, osmotic time, and the temperature of the solution under certain experimental conditions. The effective diffusivity of moisture and solute were estimated using the analytical solution of Fick's second law of diffusion. The moisture and effective diffusivities of sugar in the above osmotic dehydration conditions were in the range of 1.77 × 10-9 -2.10 × 10-9 and 1.36 × 10-9 -1.60 × 10-9 m2 .s-1 , respectively. CONCLUSION: The pretreatment of sugar osmosis greatly reduced the microwave vacuum drying time in the latter part of the dehydration period and increased anthocyanin retention.
BACKGROUND: The combination of sugarosmotic dehydration and microwave vacuum drying is an effective method for the dehydration of blackberries, the retention of their antioxidant properties, and the extension of their shelf life. Mass transfer during the osmotic dehydration of blackberries in sugar solution was investigated together with its influence on microwave vacuum drying characteristics, and the retention rate of anthocyanins in dried frozen blackberries. RESULTS: The concentrations of the osmotic solutions that were tested contained 40%, 50%, and 60% sugar, and the osmotic solution temperatures were 30 °C, 40 °C, and 50 °C. The solution-to-blackberry mass ratio was 10:1 (w/w) and the process duration varied from 0 to 5 h. A two-parameter mathematical model was used to describe mass transfer in the osmotic dehydration of blackberry samples and estimate moisture loss and solid gain in the final equilibrium. The results showed that the dehydration rate and solid gain rate of the blackberries increased with an increase in osmotic concentration, osmotic time, and the temperature of the solution under certain experimental conditions. The effective diffusivity of moisture and solute were estimated using the analytical solution of Fick's second law of diffusion. The moisture and effective diffusivities of sugar in the above osmotic dehydration conditions were in the range of 1.77 × 10-9 -2.10 × 10-9 and 1.36 × 10-9 -1.60 × 10-9 m2 .s-1 , respectively. CONCLUSION: The pretreatment of sugar osmosis greatly reduced the microwave vacuum drying time in the latter part of the dehydration period and increased anthocyanin retention.
Authors: Lívia Muritiba Pereira de Lima Coimbra; Adrielle Zagmignan; Paulo Victor Vieira Gomes; Jânaira Farias Araujo; Gabrielle Damasceno Costa Dos Santos; Rita de Cássia Mendonça de Miranda; Silvana Magalhães Salgado; Samara Alvachian Cardoso Andrade; Luís Cláudio Nascimento da Silva Journal: Foods Date: 2022-03-10