Comparison of Two Methods of Purple Top Turnip Drying Based on Energy Consumption and Quality Parameters

Document Type : Research Article

Authors

• H. Sadrnia
• H. Monfared
• M. Khojastehpour

Ferdowsi University of Mashhad

https://doi.org/10.22067/jam.v5i1.22910

Abstract

Drying is one of the oldest methods to preserve agricultural products and hence expanding the food market. By drying, the agricultural products can be stored and transferred to the market throughout the year. One of the most important and nutritious vegetables is turnip which can be used by drying in out of season. In this research, the hot air and vacuum drying methods of turnip were compared. The effect of independent factors including temperature and vacuum, on dependent factors such as the shrinkage, rehydration and rate of electric energy consumption on final products of turnip were investigated. A randomized completely design for hot air dryer and a factorial experiment based on completely randomized design for drying under vacuum condition were used. Results showed that the temperature and vacuum have affected the shrinkage, rehydration and electricity consumption. Shrinkage parameter is more depend on the final humidity of product and the energy consumption of the devices depends on time. The best quality of dried turnip was achieved from hot air drying device with final humidity of 14±1%, shrinkage of 39.98%, rehydration of 4.45 and consumed electricity of 32.36 kWh kg-1 of DM in 60˚C. For the vacuum drying device the best quality of produce achieved with shrinkage of 38.12%, rehydration of 4.87 and consumed electricity of 30.58 kWh kg-1 of DM in vacuum condition of 10 kPa in 60˚C. Comparison of results showed that the vacuum dryer is more appropriate than the hot air dryers for drying turnip with better quality and lower power consumption.

Keywords

• Rehydration
• Shrinkage
• Vacuum drier
• Turnip

20.1001.1.22286829.1394.5.1.15.6

References

1. Abbasi, S., S. M. Mousavi, and M. Mohebbi. 2011. Investigation of changes in physical properties and microstructure and mathematical modeling of shrinkage of onion during hot air drying. Iranian Food Science and Technology Research Journal 7: 92-98.

2. Aghbashlo, M., M. H. Kianmehr, and A. Arabhosseini. 2009. Performance analysis of drying of carrot slices in a semi-industrial continuous band dryer. Journal of Food Engineering 91: 99-108.

3. Artnaseaw, A., S. Theerakulpisut, and C. Benjapiyaporn. 2010. Development of a vacuum heat pump dryer for drying chilli. Biosystems Engineering 105: 130-138.

4. Bondaruk, J., M. Markowski, and W. Błaszczak. 2007. Effect of drying conditions on the quality of vacuum-microwave dried potato cubes. Journal of Food Engineering 81: 306-312.

5. Colak, N., and A. Hepbasli. 2007. Performance analysis of drying of green olive in a tray dryer. Journal of Food Engineering 80: 1188-1193.

6. Coogan, R. C., and R. B. H. Wills. 2002. Effect of drying and salting on the flavour compound of Asian white radish. Food Chemistry 77: 305-307.

7. Cui, Z. W., S. Y. Xu, and D. W. Sun. 2004. Microwave-vacuum drying kinetics of carrot slices. Journal of Food Engineering 65: 157-164.

8. Food and Agriculture Organization of the United Nations (FAO). 2011. FAOSTAT. Available from: http://faostat.fao.org. Accessed 1 September 2013.

9. Kamali, E. 2011. Construction of a laboratory scale vacuum dryer and investigate the possibility of drying kiwifruit. M.Sc. Thesis. Faculty of Agriculture. Ferdowsi University of Mashhad. Iran. (In Farsi).

10. Lee, J. H., and H. J. Kim. 2009. Vacuum drying kinetics of Asian white radish (Raphanus sativus L.) slices. LWT - Food Science and Technology 42 (1): 180-186.

11. Maskan, M. 2001. Drying, shrinkage and rehydration characteristics of kiwifruits during hot air and microwave drying. Journal of Food Engineering 48(2): 177-182.

12. Miranda, M., A. Vega-Galvez, P. Garcia, K. Di Scala, J. Shi, S. Xue, and E. Uribe. 2010. Effect of temperature on structural properties of Aloe vera (Aloe barbadensis Miller) gel and Weibull distribution for modelling drying process. Food and Bioproducts Processing 88: 138-144.

13. Mortazavi, S. A. 2004. Dehydration of Foods. Ferdowsi University of Mashhad press. Mashhad. Iran.

14. Schultz, E. L., M. M. Mazzuco, R. A. F. Machado, A. Bolzan, M. B. Quadri, and M. G. N. Quadri. 2007. Effect of pre-treatments on drying, density and shrinkage of apple slices. Journal of Food Engineering 78: 1103-1110.

15. Suslow, T. 2000. UC Davis Post Harvest Technology Research & Information Center Produce Facts- Apple: Golden Delicious. Department of Plant Sciences. University of California. Available from: http://postharvest.ucdavis.edu/Produce/ProduceFacts/Fruit/golden.shtml. Updated April 1, 2010. Accessed 1 September 2013.

16. Vega-Galvez, A., K. Ah-Hen, M. Chacana, J. Vergara, J. Martinez-Monzo, P. Garcia-Segovia, R. Lemus-Mondaca, and K. Di Scala. 2012. Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices. Food Chemistry 132: 51-59.

17. Wang, J., Y. Z. Lia, R. R. Chenb, L. Y. Baoa, and G. M. Yang. 2007. Comparison of volatiles of banana powder dehydrated by vacuum belt drying, freeze-drying and air-drying. Food Chemistry 104: 1516-1521.

18. Wua, L., T. Orikasaa, Y. Ogawab, and A. Tagawa. 2007. Vacuum drying characteristics of eggplants. Journal of Food Engineering 83: 422-429.