Saffron Quality Research Articles

Saffron Drying with a Heat Pump–Assisted Hybrid Photovoltaic–Thermal Solar Dryer

Saffron is the most expensive spice and Iran is the largest producer of this crop in the world. Saffron quality is profoundly affected by the drying method. Recent research has shown that hybrid photovoltaic–thermal solar power systems are more efficient in comparison with individual photovoltaic and thermal systems. In addition, heat pump dryers are highly energy efficient. Furthermore, they are suitable for heat-sensitive crops such as saffron. Therefore, in the present study, the performance of a hybrid photovoltaic–thermal solar dryer equipped with a heat pump system was considered for saffron drying, in order to obtain a high-quality product and reduce fossil fuel consumption. The effect of air mass flow rate at three levels (0.008, 0.012, and 0.016 kg/s), drying air temperature at three levels (40, 50, and 60°C), and two different dryer modes (with and without the heat pump unit) on the operating parameters of the dryer was investigated. The results of the investigation showed that total drying time and energy consumption decreased as air flow rate and drying air temperature increased. Applying a heat pump with the dryer led to a reduction in the drying time and energy consumption and an increase in electrical efficiency of the solar collector. The average total energy consumption was reduced by 33% when the dryer was equipped with a heat pump. Maximum values for electrical and thermal efficiency of the solar collector were found to be 10.8 and 28%, respectively. A maximum dryer efficiency of 72% and maximum specific moisture extraction rate (SMER) of 1.16 were obtained at an air flow rate of 0.016 kg/s and air temperature of 60°C when using the heat pump.

Biochemical, Antioxidant and Antineoplastic Properties of Italian Saffron (<i>Crocus sativus L</i>.)

Saffron, the most expensive spice in the world, is got by Crocus sativus L. stigmas. The production of this substance has attracted human interest, since ancient cultures, for its medicinal and culinary properties. Because of saffron high economic value, sometimes, since Middle Ages, it is adulterated with other vegetal materials, dyes or synthetic molecules. Object of this work was the study of one of the best world saffron: Civitaretenga (AQ, Central Italy) C. sativus. Taste, color and aroma of Civitaretenga spice were determined, according to international standards (ISO/Technical Specification 3632), to define its high quality. A biochemical approach was then applied to obtain a secondary metabolite profile of this product. So, crocins, total phenolic content, flavonoids and phenolic acids were detected by HPLC-DAD and spectrophotometric analysis. Moreover, in vitro antioxidant properties and in vivo antineoplastic effects, on highly metastatic murine B16-F10 melanoma cell line, were successfully revealed in Civitaretenga C. sativus extract. All these data confirmed the elevated quality of Civitaretenga saffron and its highly reducing and chemopreventive activity.

Picrocrocin Kinetics in Aqueous Saffron Spice Extracts (Crocus sativus L.) upon Thermal Treatment

The kinetics of picrocrocin degradation in aqueous extracts of saffron upon thermal treatment from 5 to 70 °C have been studied, together with the degradation of purified picrocrocin in water at 100 °C. The best fits to experimental data were found for a second-order kinetics model. Picrocrocin showed high stability with half-life periods (t(1/2)) ranging from >3400 h at 5 °C in saffron extracts to 9 h in the experiments with purified picrocrocin at 100 °C. In saffron extracts, the evolution of the rate constant (k) with temperature showed maximum values at 35 °C, and filtration of the extracts contributed to picrocrocin stability. In the case of purified picrocrocin, the generation of safranal in the first 5 h (yield up to 7.4%) was confirmed. Spectrometric parameters used in saffron quality control (E(1cm)(1%) 257 nm and ΔΕ(pic)) were not appropriate for documenting the evolution of picrocrocin.

Effects of mild temperature conditions during dehydration procedures on saffron quality parameters

The dehydration procedure is responsible for saffron sensorial properties: colour, taste and aroma. Changes in the compounds responsible for these characteristics have been studied when dehydration processes at high and low temperature are employed. However, the evolution of these changes at mild temperatures is not available in the current bibliography. In this paper the effect of different mild conditions (18-20 degrees C for 24 h, 40-50 degrees C for 75 min and 55 degrees C for 75 min) applied to 45 saffron samples with the same origin was investigated. Crocetin esters, the compounds responsible for saffron colour, increased their content with no significant differences from other processes when high temperatures (55 degrees C) were used, thus producing a noticeable increment in saffron colouring capability. Similar behaviour was obtained for picrocrocin, the compound responsible for saffron taste, with higher average content at the highest temperature (55 degrees C) but without significant differences with the inferior conditions (40-50 degrees C). However, more volatile compounds were generated, especially safranal,at higher temperatures, e.g. 55 degrees C, during the dehydration procedure. The results found support the idea for employing mild to high temperatures during the dehydration process of saffron.

CORM SIZE AND INCUBATION EFFECTS ON TIME TO FLOWERING AND THREADS YIELD AND QUALITY IN SAFFRON PRODUCTION IN ARGENTINA

Saffron flowering is greatly concentrated in time. In San Carlos, Mendoza, Argentina (33°44'S), 75% of flowers emerge at 7 times within a lapse of 20 days; in just 2 of these days, 50% of anthesis occurs. Due to this fact, the work intensity on the crop is extremely variable and the availability of manual labor is always challenging. The previous works of Molina et al. (2004) on saffron flowering physiology allow extending and arranging the flowering period at regular intervals, by means of incubating corms under controlled temperature conditions. The aim of this work was to verify possibilities of extending and modifying the flowering time of saffron in Argentina, evaluating the effect on flowers and saffron production of corm size and the duration of incubation under summer-like conditions (23-27°C), and comparing results from controlled environments with field crop data as well. Two categories of corm size (S3 and S4, 2.5-3.4 cm and 3.5-4.4 cm of equatorial diameter respectively), in six periods of incubation (between 59 and 101 days), were tested. Saffron quality was assessed following ISO standards. Saffron production under controlled environment was superior in yield as well as in quality to that obtained in the field. Corm size categories proven resulted of high agronomic usefulness, permitting the discrimination of production levels according to corm biomass. S4 corms were three times more productive than S3. There was a linear positive relationship between days of incubation and harvest time, allowing to forecast the flowering period and to improve the programmed use of farm facilities. Under these conditions, an earlier flowering up to 29 days was possible in relation to the field crop.

SUSTAINABLE PRODUCTION OF HIGH QUALITY SAFFRON (CROCUS SATIVUS L.) IN SOME MOROCCAN AREAS

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 (R 2 =0.84, 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.

Microbiological quality of saffron from the main producer countries.

A microbiological study of saffron spice was undertaken in the context of a European research project (Methodologies for Implementing International Standards for Saffron Purity and Quality, the acronym for which is SAFFIC), analyzing 79 samples obtained from the main producer countries, namely Greece, Iran, Italy, Morocco, and Spain. Current microbiological quality criteria are the same as for other spices, but saffron is added in minute quantities during the cooking process, so the health risk associated with microbial contamination might be lower. We did not detect Salmonella either by culture or by PCR methods in any sample, and Escherichia coli was only found in five samples. Enterobacteriaceae were frequently found (70.9% of the samples), but most of them belonged to species of probable environmental origin. Aerobic sporulated bacteria were also common, but only three samples contained Bacillus cereus at low levels (<200 CFU g(-1)). Clostridium perfringens counts were also very low, with only one sample reaching >100 CFU g(-1), an acceptable value. Overall, microbial contamination in saffron was markedly lower than it was in other spices.

Quantification of saffron ( Crocus sativus L.) metabolites crocins, picrocrocin and safranal for quality determination of the spice grown under different environmental Moroccan conditions

The primary goal of this study was 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 has to be evaluated prior to recommendation for commercial production. For this purpose, saffron was grown in experimental plots for the first time in eleven different experimental zones with a disparity of altitudes, soils and climates. High-performance liquid chromatography (HPLC) was used to quantify the most important saffron components crocins, picrocrocin, and safranal which are respectively responsible for its colour, taste and odour. The respective average values, in % dry matter, across all sites altogether are 29.01 ± 5.6; 14.04 ± 7.1 and 0.22 ± 0.11. The statistical analysis shows that crocins are stable under each specific environment tested ( p > 5%) for 3 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. Analysis of environmental impact on saffron quality showed that just the altitude affects crocins ( R 2 = 0.84, p < 0.05).

State of Art of Saffron (Crocus sativus L.) Agronomy: A Comprehensive Review

Saffron (Crocus sativus L.) is the most expensive spice of the world, and it is one of the 85 members of the genus Crocus. It is native of Asia Minor, and it is cultivated in Mediterranean countries. Saffron predominantly contains certain chemical constituents that are responsible for imparting colour, flavour, and aroma. Some of its components have cytotoxic, anti-carcinogenic and anti-tumor properties. Since, saffron is a triploid (2n = 3x = 24) plant and fails to produce seed upon selfing or crossing, so it is propagated through corms. The growing area for saffron is not extensive, although its demand in the international market is increasing. Research activities have been initiated to develop new production technologies of this spice in many countries. Saffron grows best in friable, loose, low-density, well-watered, and well-drained clay calcareous soils. Besides, climate and soil, planting time, seed/corm rate, planting depth, corm size/weight, crop density, nutrient management, weed management, growth regulators, harvest, and post-harvest management also influence saffron quality and quantity. In this paper, an attempt has been made to compile the recent agronomic research on saffron for commercial flower and corm production.

Quality and Functionality of Saffron: Quality Control, Species Assortment and Affinity of Extract and Isolated Saffron Compounds to NMDA and σ1(Sigma-1) Receptors

Extracts from saffron, the dried stigmata from Crocus sativus L., are being used more and more in preclinical and clinical trials for the treatment of cancer and depression. Because of the known quality problems of saffron, HPLC methods on RP(18) 2.5 microm and monolithic RP(18) material have been developed and validated for quality control including the quantification of crocins 1 to 5, crocetin, picrocrocin and the degradation products, the CIS-crocins. Additionally, a GC-MS method has allowed detection and quantification of the volatile compounds from the pentane extract of saffron. Both systems together allowed the comprehensive characterisation of saffron herbal material and extracts for clinical/preclinical trials. For effective preparation of the respective reference standards, a fast centrifugal partition chromatography (FCPC) method was developed allowing the quick isolation of crocins 1, 2, 5 and picrocrocin in good yields. Using these chromatographic methods and the reference standards, a representative survey of saffron from the global market indicated a high variability of quality, especially concerning the amounts of volatile compounds in saffron samples. A specification for high-quality saffron of >20% crocins, >6% picrocrocin and not less than 0.3% of volatiles, calculated as sum of safranal, isophorone and ketoisophorone, was developed. Because no detailed pharmacological studies are available to explain the clinical effects of saffron for the treatment of cancer and depression, receptor binding studies were performed. Saffron extracts and crocetin had a clear binding capacity at the PCP binding side of the NMDA receptor and at the sigma(1) receptor, while the crocins and picrocrocin were not effective. These data could give biochemical support for the above-mentioned pharmacological effects of saffron.

Saffron, an alternative crop for sustainable agricultural systems. A review

Saffron (Crocus sativus L.) is an autumnal flowering geophite whose dried stigmas, well known for their aromatic and colouring power, have been used since immemorial time as a spice in human nutrition, for medicinal purposes and as a dye. Many doubts remain on its origin; it was probably selected and domesticated in Crete during the Late Bronze Age. Saffron is an autotriploid geophyte species, self- and out-sterile and mostly male-sterile and therefore unable to produce seed, that reproduces by means of corms. Furthermore, it has a reverse biological cycle compared with the majority of cultivated and spontaneous plants: flowering first in October–November, then vegetative development until May, which means that the vegetative development is not directly important for production of stigmas, but for the production of new corms. Due to its unique biological, physiological and agronomic traits, saffron is able to exploit marginal land and to be included in low-input cropping systems, representing an alternative viable crop for sustainable agriculture. Notwithstanding this great potential and the considerable increase in new generation consumer demand for saffron, the future of the plant is still uncertain. Indeed, the main obstacles to saffron production are: (1) the limited areas of cultivation in countries where it is traditionally grown, (2) the great amount of sophisticated spice, (3) management techniques executed by hand, and (4) the very high price of the spice. Here we review the main biological, genetic and ecological traits associated with agronomic management techniques of saffron in relation to environmental conditions. Colour, taste and aroma are the essential features on which the quality of saffron stigmas is founded. In turn, these aspects are strictly connected with the biomolecular composition of the stigmas, namely, the carotenoids and their derivatives. With this in mind, the biosynthetic pathway that leads to the formation of saffron secondary metabolites and their abundance in the spice is presented, together with the biomedical properties commonly associated with saffron. Furthermore, a detailed overview of the more recent instrumental methods to assess the quality of saffron, strictly from a chemical point of view, will be discussed.

Quality and functionality of saffron: quality control, species assortment and affinity of extract and isolated saffron compounds to NMDA and sigma-1 receptors

Extracts from saffron are used for treatment of cancer and depression. Because of known quality problems HPLC methods on RP18 2.5µm and monolitic RP18 material were developed for quality control including the quantification of crocins 1 to 5, crocetin, picrocrocin and the degradation products cis-crocins. A GC-MS method allowed detection and quantification of the volatile compounds from saffron pentane extract. Both systems together allowed comprehensive characterization of saffron herbal material and extracts for clinical/preclinical trials. Based on a wide analytical survey of saffron from the global market a specification for high-quality saffron of >20% crocins, >6% picrocrocin and not less than 0.3% of volatiles, calculated as sum of safranal, isophorone and ketoisophorone, was developed.

The effect of Bacillus subtilis FZB24® on flowers quantity and quality of saffron (Crocus sativus L.)

The effect of Bacillus subtilis FZB24® on flowers quantity and quality of saffron (Crocus sativus L.)

Near-Infrared Spectroscopy in Saffron Quality Control: Determination of Chemical Composition and Geographical Origin

Near-infrared reflectance spectroscopy has been applied for the first time to saffron spice to determine the chemical composition and geographical origin of 111 samples from the there main producers' countries: Iran, Greece, and Spain. The validation procedures with the results obtained by UV-vis and HPLC-DAD measurements demonstrated that this technique is appropriate to determine the following parameters: moisture and volatile content, coloring strength, (250 nm), and (330 nm), established on the ISO 3632 Technical Specification Normative and used to certify saffron quality in the international market. Also, it can be used to estimate the content of the five main crocetin glycosides, the compounds responsible for saffron color, the best correlations being for trans-crocetin di-(beta-D-gentibiosyl) ester (R2= 0.93), trans-crocetin (beta-D-glucosyl)-(beta-D-gentibiosyl) (R2= 0.94), and picrocrocin (R2= 0.92), the compound accepted as responsible for saffron bitterness. Finally, a discriminant analysis among the three geographical origins reveals that Iranian samples are the most different, whereas Greek and Spanish samples are more similar. All of these results reveal that NIRS spectroscopy has an enormous potential for its application to saffron quality control as the results are obtained in 2 min and without any sample manipulation.

Agronomic management of saffron (Crocus sativus) A review

Saffron (Crocus sativus L.) is the costliest spice in the world, known for its colouring and aromatic and medici- nal properties. It is witnessing a declining trend in area and productivity in most of the saffron-producing countries. The decline is attributed to the degradation in soil fertility, changing climatic patterns, water stress, increasing labour cost and increasing biotic stress under the changing climate. Since the crop is propagated vegetatively, scope of genetic improvement through breeding techniques is very little. In order to reverse the declining trend in area and productivity, proper implementation of best agronomic practices assumes a very high importance in such a crop. Among the agronomic practices, the quality of corms, planting and establishment methods, balanced fer- tilization, water management, weed management and post-harvest handling have a profound effect on the pro- ductivity and quality of saffron. Mechanization in land preparation, planting, intercultural operations, harvesting and post-harvest processing can reduce the cost of production and increase the net profit. In this review, an at- tempt has been made to review the best agronomic practices evaluated across the saffron-growing regions of the world and their role in sustainable saffron production.

Note. Safranal Content in Spanish Saffron

Safranal is the compound mainly responsible for the aroma of saffron spice and can be used as a measure of saffron quality. It is described a “safranal value” of 269 (mostly Spanish) saffron samples by means of a spectrophotometric method based on ISO 3632 and the safranal content using a thermal desorption-gas chromatography method. The variation range of safranal was obtained from both methods, although there was no acceptable lineal correlation between them. Among all saffron samples the Spanish ones had the highest levels and those from Iran the lowest, which might be attributed to the different processes used for dehydrating the stigmas.

Post-Harvest Degradation of Carotenoid Glucose Esters in Saffron

It has been found that an indoor cultivation system of Crocus sativus L. is more favorable with regard to the quality of saffron, as compared to the usual cultivation in an open field. Carotenoid glucose esters increase from the period before blooming and reach the maximum in the full blooming period, and are sensitive for the presence of oxygen, light irradiation, and beta-glucosidase. Moreover, it is evident that storage of saffron at -20 degrees C promotes the constant supply of saffron with a homogeneous pharmacological activity.

Synthesis of Crocin, Picrocrocin and Safranal by Saffron Stigma-like Structures Proliferatedin Vitro

Crocin, picrocrocin, and safranal as the major secondary metabolites are important for the high quality of spice saffron. Crocin and picrocrocin were detected in stigma-like structures proliferated in vitro. Safranal appeared after heat treatment. The contents and relative ratio of these substances in the stigma-like structures were similar to those in intact young stigmas, indicating that these stigma-like structures showed not only morphological but also biochemical similarity to the intact stigmas.

Synthesis of crocin, picrocrocin and safranal by saffron stigma-like structures proliferated in vitro.

Crocin, picrocrocin, and safranal as the major secondary metabolites are important for the high quality of spice saffron. Crocin and picrocrocin were detected in stigma-like structures proliferated in vitro. Safranal appeared after heat treatment. The contents and relative ratio of these substances in the stigma-like structures were similar to those in intact young stigmas, indicating that these stigma-like structures showed not only morphological but also biochemical similarity to the intact stigmas.