Infrared Radiation and Microwave Vacuum Combined Drying Kinetics and Quality of Raspberry
详细信息 查看全文
- 作者：Xu Si ; Qinqin Chen ; Jinfeng Bi ; Jianyong Yi ; Linyan Zhou and Xinye Wu
- 刊名：Journal of Food Process Engineering
- 出版年：2016
- 出版时间：August 2016
- 年：2016
- 卷：39
- 期：4
- 页码：377-390
- 全文大小：168K
- ISSN：1745-4530
文摘
Infrared radiation and microwave vacuum combined drying (IR-MVD) kinetics and quality of raspberries under different microwave powers (400, 600, 800 W) and vacuum pressures (45, 65, 85 kPa) were investigated. Drying processes were found to be well fitted with Henderson and Pabis model for infrared radiation drying (IRD) and Midilli model for microwave vacuum drying (MVD). Drying time was reduced and moisture effective diffusivity (Deff) was promoted with the increase of microwave power. In terms of vacuum pressure, the most rapid moisture diffusion was noted at 65 kPa. IR-MVD led to brighter products but caused decreases in redness values. The highest a* value (11.33), lowest ΔE value (12.66) and largest h° value (9.01) were noted at the condition of 600 W and 85 kPa. No significant difference was found between crispness values for different IR-MVD conditions. Good rehydration property was obtained under the strongest microwave power and the highest vacuum pressure. Additionally, anthocyanin losses happened and antioxidant activity declined during dehydration. The highest anthocyanin retention (66.24%) was obtained at the condition of 600 W and 65 kPa. The maximum retention of the antioxidant capacity determined by ABTS (2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)), DPPH (1,1-diphenyl-2-picrylhydrazyl) and FRAP (ferric reducing ability of plasma) were 72.12, 75.03 and 55.19%, respectively, at the vacuum pressure of 85 kPa and microwave power of 600 W. By comparison, the time IR-MVD used was only 55.56% of IRD; moreover, raspberries dried by IR-MVD showed 25.63% higher rehydration ratio, 2.4 times higher crispness value, 17.55% higher anthocyanin retention and 21.21% higher DPPH radical-scavenging activity than IRD.