Effects of Different Drying Methods on Moisture Content, Drying time and Qualitative Criteria of Saffron Stigma

Mollafilabi, Abdollah; Khorramdel, Surur; Shabahang, Javad

doi:10.22077/jsr.2018.1872.1072

Document Type : Original Article

Authors

¹ Assistant Professor, Research Institute of Food Science and Technology

² Department of Agrotechnology, Faculty of agriculture, Ferdowsi University of Mashhad

³ FUM

https://doi.org/10.22077/jsr.2018.1872.1072

Abstract

Saffron is considered to be one of the most expensive agricultural products in the world. Saffron specific compounds are crocin, picrocrocin and safranal. Different drying methods not only differ in energy consumption but also, influence the chemical and sensory properties of saffron. Accordingly, the current study was aimed to investigate the effect of different drying techniques on quality of saffron. The experiment was laid out as a completely randomized design with four replications at Ferdowsi University of Mashhad Faculty of Agriculture, Mashhad Iran in 2017. Four different drying techniques i.e. traditional technique (shade dried at laboratory temperature), oven (at 40, 60 and 80°C), microwave (at 200, 400 and 600 watts), freeze (at -18°C for 5 hr and then heating at 60±5°C with evacuation intervals of 15, 10, 10 and 10 minutes) were considered as the treatments. Chemical tests were performed according to ISO 3632-2 (E) 1993 and safranal content was measured using chromatography. The results indicated that the highest and the lowest moisture content were observed in traditional method (7.23%) and microwave technique at 600 w (1.47%), respectively. Freezing technique declined drying time compared to traditional method up to 69%. Chemical properties of stigma including moisture percentage, total ash, insoluble ash in acid and soluble extract in cold water and nitrogen are in accordance with Iranian National Standards. The maximum picrocrocin (140.66%) and safranal (42.64%) were obtained when stigmas were dried using microwave technique at 600 w. The maximum crocin percentage was related to freezing technique (299.64 mg.kg^-1). The maximum (245.91 mg.kg^-1) and minimum (88.15) safranal weight percentage were observed when freezing and traditional techniques were practiced. The lowest picrocrocin, safranal and crocin contents were obtained for oven at 800°C with 38.01, 13.18 and 109.44%, respectively. According to the results, although preserving all the qualitative features of saffron during drying process seems difficult, in order to achieve a higher level of quality controlled methods such as microwave or freezing techniques are recommended.

Keywords

References

Abrishamchi, P., 2003. Evaluation of some biochemical changes related to seed dormancy and flower formation in saffron. Third National Symposium on Saffron, 11-12 December. Mashhad, Iran. [In Persian].

Alonso, G.L., Salinas, M.R., Esteban-Infantes, F.J., and Sánchez-Fernández, M.A., 1996 Determination of safranal from saffron (Crocus sativus L.) by thermal desorption-gas chromatography. J. Agric. Food Chem. 44(1), 185-188.

Alonso, G.L., Salinas, M.R., Sanchez- Fernandez, M.A., and Garijo, J., 2001 Safranal content in Spanish saffron. Food Sci. Technol. Int. 7(3), 225-229.

Alonso, G.L., Varon, R., Gomez, R., Navaro, F., and Salinas, M.R., 1990. Auto-oxidation in saffron at 40 and 75 relative humidity. J. Food Sci. 55(2), 595-596.

Alonso, G.L., Varon, R., Salinas, M.R., and Navaro, F., 1993. Auto-oxidation of crocin and picrocrocin in saffron under different storage conditions. Bollettino Chimico Farmaceutico. 132, 116-120.

Atefi, M., 1999. The effect of freeze-drying method on saffron qualitative traits. Master thesis, Shahid Beheshti University, Faculty of Nutrition Sciences and Food Industry. Iran. [in Persian with English Summary].

Atefi, M., 2006. Saffron, Chemistry, Quality Control and Processing. Beynolnahreyn Press. First Edition. Iran. [In Persian].

Atefi, M., Akbari Oghza, AR., and Mehri, A., 2013. Effect of drying on chemical and sensory properties of saffron. Iran. J. Nutr. & Food Technol. 8(3), 201-208. [in Persian with English Summary].

Atefi, M., Taslimi A., Hasas, M.R., and Mazlomi, MT., 2004. Effect of freeze drying method on saffron qualitative traits. Iran. J. Food Sci. & Technol. 1(2), 39-47. [in Persian with English Summary].

Azizi Zahan, A.A., Kamgar Haghighi, A.A., and Sepaskhah, A., 2006. Effect of method and duration of irrigation on production of corm and flowering on saffron. J. Sci. Technol. Agric. & Nat. Res. 10, 45-53. [In Persian with English Summary].

Basker, D., Palevitch, D., and Putievsky, E., 1993. Saffron the costliest spice: drying and quality and price. Acta Hort. 344, 86-97.

Blose, N., 2001. Herb Drying Handbook: Includes Complete Microwave Drying Instructions. Sterling Publishing Co. Inc., New York, 96 pp.

Bolandi, M., Shahidi, F., Sedaghat, N., and Farhoush, R., and Mousavi-Nik, H., 2008. Shelf-life determination of saffron stigma: Water activity and temperature studies. World Appl.Sci. J. 5(2), 132-136.

Bushbeck E., Keiner E., and Klinner J., 1967. Trocknungsphysikalische und Warmetechnische Untersuchung Zur Trocknung von Pfefferminze (Physical and thermal properties affecting drying characteristics of peppermint). Archiv fur Landtechnik 2, FL. pp. 163-200.

Caceres, A., 2000. Calidad de la material prima para la elaboracion de productos fitofarmaceuticas. Primer Congreso.

Carmona, M., Zalacain, A., Pardo, J.E., Lopez, E., Alvarruiz, A., and Alonso, G.L., 2005. Influence of different drying and aging on saffron constituents. J. Agric. & Food Chem. 53, 3974-3979.

Diaz, G.R., Martinez-Monzo, J., Fito, P., and Chiralt, A., 2003. Modeling of dehydrating and rehydrating of orange slices in combined microwave/air drying. Innov. Food Sci. & Em. Technol. 4, 203-209.

Drouzas, E., Tsami, E., and Saravacos, G.D., 1999. Microwave/vacuum drying of model fruit gels. J. Food Eng. 63, 349-359.

Fatemi, H., 2001. Food Chemistry. Enteshar Corporation. p. 480. [In Persian].

Hemmati Kakhki, A., 2001. Effects of drying methods on quality of saffron (Crocus sativus L.). Pajouhesh Va Sazandegi. 14(51), 25-31. [in Persian with English Summary].

Hevia, F., Melin, P., Berti, M., Fischer, S., and Pinichet, C., 2002. Effect of drying temperature and air speed on cichoric acid and alkylamide content of Echinaceae purpurea. Acta Hort. 576, 321-325.

Hosseini Nejad, M., 2000. Evaluation of quality characteristics and microbial contamination of saffron samples dried by microwave. ISHS Acta Horticulturae. 650, International Symposium on Saffron Biol. & Biotechnol. doi: 10.17660/ActaHortic.2004.650.43

International FITO., 2000. Por la investigacion, conservacion y diffusion del conocimiento de lasplantasmedicinals”. 27-30 de septiembre, 2000, Lima, Peru.

Izli, N., Izli, G., and Taskin, O., 2017. Influence of different drying techniques on drying parameters of mango. Food Sci. & Technol. 37(4), http://dx.doi.org/10.1590/1678-457x.28316.

Kafi, M., Koocheki, A., Rashed, M.H., and Nassiri, M., 2006. Saffron (Crocus sativus): Production and Processing. CRC Press, 252 pp.

Mannio, S., and Amelotti, G., 1977. Determination of optimum humidity for storage of saffron. Rivista della Società Italiana di Scienze dell'Alimentazione. 6.(2).(95).1977.F.S.T.A. 10T, 599.

Molina, R.V., Renav Morata, B., Nebauer, S.G., Garcia Luis, A. and Guardiola, J.L., 2010. Greenhouse saffron culture temperature effects on flower emergence and vegetative growth the plants. Acta Hort. 850, 91-94.

Morimoto, S., Umezaki, Y., Shoyama, Y., Saito, H., Nishi, K., and Irino, N., 1994. Post-harvest degradation of carotenoid glucose esters in saffron. Planta Medica. 60(5), 438-440.

Negbi M., 1999. Saffron (Crocus sativus L). Netherland: Harwood Academic Publishers. Pp. 81-92.

Orfanou, O., and Tsimidou M., 1996. Evaluation of the colouring strength of saffron spice by UV- Vis spectromentry. Food Chem. 57(3), 463-469.

Parker, J.C., 1999. Developing a herb and spice industry in Callide Valley, Queensland. A report for the Rural Industries Research and Development Corporation. RIRDC Publication No. 99, p. 45.

Rania, B.L., Agarwal, S.G., Bhatia, A.K., and Gaur, G.S., 1996. Changes in pigments and volatiles of saffron (Crocus sativus L.) during processing and storage. J. Sci. Food & Agric. 71: 27-32.

Rödel W, Petrzika M., 1991 Analysis of the volatile components of saffron. J. High Resol. Chromatog. 14(11), 771-774.

Rudy, S., 2009. Energy consumption in the freeze- and convection-drying of garlic. Teka Komisji Motoryzacji i Energetyki Rolnictwa O.L. PAN, 9, 259–266.

Saffron Standard., 2003. Properties. Institute of Standards and Industrial Research of Iran. Karaj, Iran. p. 1-259. [In Persian].

Shoyama, Y., 2002. Study on stability of red color component, crocin. The san-Eigen foundation for food. Chem. Res. Research Reports No. 8.

Soysal, Y., and Oztekin, S., 2001. Technical and economic performance of a tray dryer for medicinal and aromatic plants. J. Agric. Eng. Res. 79, 73-79.

Sujata, V., Ravishankar, G.A., and Venkataraman, L.V., 1992. Methods for the analysis of the saffron metabolites crocin, croecetins, picrocrocin and safranal for the determination of the quality of the spice using thin- layer chromatography high-performance liquid chromatography and gas chromatography. J. Chromatog. 624(1-2), 497-502.

Von Hörsten, D., 1999. Einsatz von Mikrowellenenergie und Hochfrequenztechnik zur Trocknung und Entkeimung von Arznei und Gewürzpflanzen. Zeitschrift für Arznei und Gewürzpflanzen. 4(2), 101-102.

Winterhalter, P., and Straubinger, M., 2000. Saffron-renewed interest in an ancient spice. Food Rev. Int. 16(1), 39-59.