Sustainable Production of High Quality Saffron (Crocus Sativus L.) in Some Moroccan Areas

Sustainable Production of High Quality Saffron (Crocus sativus L.) in Some Moroccan Areas M. Lage a , F. Gaboun, K. Bakhy, H. Dakak and A. Zouahri National Institute of Agronomic Research (INRA) URAPVCRP, Guich, B.P6570, Rabat Morocco C.L. Cantrell Natural Products Utilization Research Unit, USDA-ARS PO Box 8048, University, MS 38677 USA Keywords: Crocus sativus L., environmental impact, Morocco, processing Abstract The main goal of this study is to propose saffron as a sustainable substitute crop with high added value in some Moroccan agricultural areas with low and erratic rainfalls for their socio-economical development. The quality of the saffron spice crop produced under different Moroccan environments has to be evaluated prior to recommendation for commercial production. For this purpose, saffron was experimented in eleven different experimental zones with a disparity of altitudes, soils and climate. High performance liquid chromatography (HPLC) was used to quantify the three saffron components crocins, picrocrocin, and safranal which are respectively responsible for its colour, taste and odor. Two commercial controls from Morocco, ‘Taliouin Saffron’ and ‘Ourika Saffron’ were tested for comparison. The first step of this work was successfully achieved and the regions for the new saffron crop introductions, based on crocins level, were identified. Analysis of environmental impact on saffron quality showed that the altitude significantly affects crocins content (R2=0.84, p<0.05), and that crocins are stable under each specific environment tested (p>0.05) during three years of study. Meanwhile, there was a large variability in safranal content for the same period (p<0.05). This suggests that post-harvest processing of saffron produced under different environments may need to be improved. INTRODUCTION Saffron crop is practiced in Morocco since a long time. Its area of production is limited to a small region in the south, especially in the Anti-Atlas Mountains, on about 600 ha. The main region of its implantation lies in the Taliouine zone (Altitude 12001630 m, latitude 30°26’N and a longitude of 8°25’W), a remote area in the Southwest of Morocco with cold winters and hot summers. The objective of this study is to propose a sustainable substitute crop with high added value in some Moroccan agricultural areas with low and erratic rainfalls for a possible extension of the regions where this valuable crop can be grown. Saffron was tested in experimental plots for the first time in eleven different experimental zones with a disparity of altitudes, soils and climates. The purpose is to determine the range of variation in the main saffron compounds, crocins, safranal and picrocrocin, as influenced by the environment and to determine the region that yields the highest saffron quality based on crocins level. MATERIAL AND METHODS Corms Collection Corms are collected in fields and growers’ reserves from the main saffron region. The experiments were conducted in the same manner as done by local farmers, under diverse environments during the years 2005, 2006 and 2007. a mlage@fulbrightmail.org Proc. 3rd IS on Saffron Eds.: M.Z. Tsimidou et al. Acta Hort. 850, ISHS 2010 235 Stigma Collection The flowers on each experimental plot were picked by hand at approximately the same time of day (from 6 to 8 am). Methods for removal of the stigma from flowers and drying conditions were kept identical to the methods used by farmers in the main saffron Moroccan regions. Stigmas were brought indoors where they were separated by hand shortly after collecting in the field, and were dried, in the shade, for 8 to 10 days. Commercial Moroccan saffron from “Taliouin” (Anti-Atlas), the main saffron growing zone in Morocco and “Le Safranier d’Ourika” in Marrakech (High Atlas) were analysed in order to compare their composition with that of saffron obtained from experimental trials. The samples were bought from known farmers and are not adulterated. Quality Analysis - Plant Materials and Chemicals Saffron stigma samples collected from various locations (zones) in Morocco and two commercial saffron samples were analysed for quality. Two standards, safranal 88% and crocins were purchased from Sigma-Aldrich (St. Louis, MO). Picrocrocin was purified in the laboratory of NPUR, USDA-ARS, Oxford, MS, USA. HPLC Analysis The HPLC system used for samples harvested during 2006 was an Agilent 1100 series consisting of a degasser, quaternary pump, ALS auto-sampler and PDA detector. An Agilent Zorbax SB-C-18, 4.6 × 250 mm, 5 μm column was used for this analysis with a column flow of 1 ml/min. Sample injections were made at 25 μl for all samples and standards. Using a solvent system of H2O and ACN, a gradient elution was used for analysis. During 2007 we tried to use the same protocol used on 2006 on a ThermoElectron Surveyor HPLC (San Jose, California) consisting of a degasser, quaternary pump, PDA detector coupled with a mass spectrophotometer LCQ advantage max. A BDS hypensil C-18 (150 × 4.6) mm × 5 µm column was used with a column flow of 1 ml/min. The analyses were triplicate for each sample. Safranal was detected at 310 nm and all crocins were detected at 440 nm and picrocrocin at 250 nm. Experimental Sites Soil properties analyses were done for the experimental sites. Meteorological data were collected from classical meteorological stations located in the region where experimental sites were located. The Global Positioning System (GPS) is used to estimate the coordinates (latitude, longitude, altitude) for each experimental site. Statistical Analysis Data for all experiments were analysed using a SAS (r) 9.1 (2007) (SAS Institute INC, Cary, NC, USA) statistical software package and Genstat Release 10.2, copyright 2007 (PC/Windows) (Law Agricultural Trust, Rothamsted Experimental Station). Statistical analysis was performed using one-way ANOVA followed by Duncan’s Multiple Range Test (DMRT) for multiple comparisons. The p-values less than 0.05 were considered statistically significant. Cluster analysis was conducted to group sites into subsets, which share the same common trait. RESULTS AND DISCUSSION Qualitative Analysis of Saffron from Different Experimental Sites Saffron quality, which is depending on the concentration of its three major metabolites, crocins, picrocrocin and safranal, is analyzed in different environments and results are presented in Table 1. The highest mean significant crocins values are achieved in both Moroccan commercial saffron and in the Marrakech experimental site (S1) (Table 1), and the highest content of picrocrocin is found in commercial saffron (C2). Meanwhile, safranal is slightly lower in commercial saffron compared to some 236 experimental sites, as S11 and S1, where average safranal obtained is the highest (Table 1). The difference noticed among sites and between sites and commercials is normally due to environmental factors, since saffron was conducted in the same way for all experimental sites, with the same processing and storage methods used by Moroccan saffron growers, and submitted to the same extraction, separation and quantification methods. Also, the genetic material obtained from the main saffron zone in the south of Morocco (Taliouin region) is tested in all the experimental trials. Environmental Impact on Saffron Quality The Pearson's correlation coefficient matrix of all the measured variables shows that the only significant positive correlations were found between altitude and crocins (p<5%). Based on results of this analysis, cluster analysis was performed to group sites into subsets, which share the same common trait based on crocins content and altitude (Fig. 1). Two groups were then identified. Group 1, which includes S1, S8, C1 and C2; which have an altitude over 1000 m and group 2 that include all the other sites, not S5, which have an altitude lower than 1000 m. The site S5 represents a coastal site with sandy and poor soil based on P and K and its pH is slightly acidic compared to other sites (pH<7), but we do not have statistical analysis for proof as to show that those factors influence saffron quality. This denotes that we would need to have multiple sites in the same region as to highlight others factors that could influence crocins production in interaction with altitude. CONCLUSION Altitude has a positive effect on crocins content. However, further researches on the impact of other environmental factors on saffron quality and the identification of the target region enabling the production of high quality saffron are to be continued. Nevertheless, this multi-year study provides important information about the region to grow saffron with high crocins content. Also this study suggests that for the experimental saffron produced under different environments, considerable improvements in the aroma content should be done without losing colour by using other drying methods. It is important to emphasize that this work constitutes the first study conducted on saffron quality determination in Morocco under diverse environments. Literature Cited Lage, M. and Cantrell, C. 2009. Quantification of Saffron (Crocus sativus L.) metabolites Crocins, Picrocrocin and Safranal for Quality Determination of the Spice Grown under Different Environmental Moroccan Conditions. Scientia Horticulturae 121:366373. 237 Tables Table 1. Determination of saffron constituents (% dry weight) under different environments in comparison to two commercial controls (C1 and C2) using HPLC method: crocins and safranal values are average of three years of experimentation (2005, 2006 and 2007), picrocrocin are values obtained during the harvest of 2006. (Sites are classified from the lowest to the highest altitude). Means with different letters in a column show differences at a significance level of 5% according to DMRT. Figures Fig. 1. Dendogram of saffron sites gathered on altitude and crocins basis. 238