Stefania Stelluti

Saffron is a geophyte grown in open field, but the possibility of year-round greenhouse cultivation is attracting increasing interest. We evaluated the application of supplemental lighting with white light emitting diodes (LEDs) in greenhouse conditions during the summer-winter period, in plants grown in pots on two benches, under two lighting treatments: natural light supplemented with LEDs (~ 260 µmol m ^− 2 s ^− 1 ) and natural light only (NL), which served as the control. LED lighting delayed flowering by almost a week (72 vs. 66 days after planting) but did not affect the mean number of flowers (4.2 flowers plant ^− 1 ) or spice yield (29.9 mg plant ^− 1 ). However, LED lighting increased the phenolic acid content in the spice (+ 52%) compared with NL, indicating an improvement in spice quality. During the subsequent vegetative phase, net photosynthesis was increased by supplemental lighting, while plant leaf area was reduced, since lighted plants developed more leaves but with a lower specific leaf area compared to control. Notably, plants under LED lighting produced more corms (7.5 vs. 6.0 corms plant ^− 1 ), with no differences in mean corm weight (3.4 g plant ^− 1 ) or starch content (645 mg g ^− 1 corm dry weight) compared with NL, suggesting a potential for increasing the yield of propagative material. Overall, supplemental LED lighting may contribute to improving spice phytochemical quality and corm multiplication, which are both agronomically relevant traits for greenhouse soilless saffron cultivation.

Saffron (Crocus sativus L.), a perennial plant of the Iridaceae family, which is also known as “red gold”, is one of the most expensive spices throughout the world. Originally, it was mainly used as a condiment and natural dye for food, and as a medicinal plant in folk medicine. Its cultivation is characterized by an extensive use of labor, since most of the crop management techniques (e.g., sowing, weeding, flower picking, and stigma separation) are performed manually. The aim of this work is to investigate how the adoption of sustainable cultivation techniques could improve the profitability of saffron at the primary level. Thus, economic and technical data were collected directly on a farm in a marginal area in Northwestern Italy, in order to compare the productivity and profitability of traditional and innovative cultivation techniques. The effect of sustainable practices, such as the use of beneficial microorganisms, that is, arbuscular mycorrhizal fungi (AMF), on the productivity of saffron was considered. In a previous work, AMF inoculation with Rhizophagus intraradices and Funneliformis mosseae led to an increase in the flower and saffron spice yields, compared to uninoculated controls. The profitability of the saffron (including tepals, its by-product) considered in our case study, expressed as economic profit (pure profit), was found to be slightly negative for the traditional cultivation method (without the use of AMF) and also, albeit to a lesser extent, for the innovative technology (with the use of AMF). This slightly negative result is mainly due to the implicit cost of family labor for both the traditional and innovative cultivation techniques. The results of our study can be considered a further step in favor of the use of cultivation techniques that improve crop productivity and, at the same time, are sustainable. They also support the spread of minor crops, which, nevertheless, are important to maintain agricultural activities in marginal territories.

Edible flowers are becoming increasingly popular as food products, since they give aroma, color, and visual appeal and are also health-promoting compounds. However, they are a highly perishable product, thus post-harvest technologies are needed to extend their marketability. In this study, active (N₂: 100%) and passive modified atmosphere packaging (MAP) technologies were applied to three edible flower species, namely Begonia grandiflora ‘Viking’, Tropaeolum majus, and Viola cornuta, stored at 4 °C. Even if the flowers’ quality decay occurred differently according to the species, active MAP better maintained petal colors and slowed down the edible flowers’ decay than passive MAP by decreasing flower respiration in all three species and sugars consumption in begonia; there was weight loss in nasturtium, and better preserved total phenolic content in begonia and viola. Coupling cold storage with active MAP can be an effective method to extend edible flowers’ post-harvest life.

To understand whether domestication had an impact on susceptibility and responsiveness to arbuscular mycorrhizal fungi (AMF) in tomato (Solanum lycopersicum), we investigated two tomato cultivars (“M82” and “Moneymaker”) and a panel of wild relatives including S. neorickii, S. habrochaites and S. pennellii encompassing the whole Lycopersicon clade. Most genotypes revealed good AM colonisation levels when inoculated with the AMF Funneliformis mosseae. By contrast, both S. pennellii accessions analysed showed a very low colonisation, but with normal arbuscule morphology, and a negative response in terms of root and shoot biomass. This behaviour was independent of fungal identity and environmental conditions. Genomic and transcriptomic analyses revealed in S. pennellii the lack of genes identified within QTLs for AM colonisation, a limited transcriptional reprogramming upon mycorrhization and a differential regulation of strigolactones and AM‐related genes compared to tomato. Donor plants experiments indicated that the AMF could represent a cost for S. pennellii: F. mosseae could extensively colonise the root only when it was part of a mycorrhizal network, but a higher mycorrhization led to a higher inhibition of plant growth. These results suggest that genetics and functional traits of S. pennellii are responsible for the limited extent of AMF colonisation.

Tepals constitute the most abundant bio-residues of saffron (Crocus sativus L.). As they are a natural source of polyphenols with antioxidant properties, they could be processed to generate valuable biorefinery products for applications in the pharmaceutical, cosmetic, and food industries, becoming a new source of income while reducing bio-waste. Proper storage of by-products is important in biorefining and dehydration is widely used in the herb sector, especially for highly perishable harvested flowers. This study aimed to deepen the phytochemical composition of dried saffron tepals and to investigate whether this was influenced by the extraction technique. In particular, the conventional maceration was compared with the Ultrasound Assisted Extraction (UAE), using different solvents (water and three methanol concentrations, i.e., 20%, 50%, and 80%). Compared to the spice, the dried saffron tepals showed a lower content of total phenolics (average value 1127.94 ± 32.34 mg GAE 100 g⁻¹ DW) and anthocyanins (up to 413.30 ± 137.16 mg G3G 100 g⁻¹ DW), but a higher antioxidant activity, which was measured through the FRAP, ABTS, and DPPH assays. The HPLC-DAD analysis detected some phenolic compounds (i.e., ferulic acid, isoquercitrin, and quercitrin) not previously found in fresh saffron tepals. Vitamin C, already discovered in the spice, was interestingly detected also in dried tepals. Regarding the extraction technique, in most cases, UAE with safer solvents (i.e., water or low percentage of methanol) showed results of phenolic compounds and vitamin C similar to maceration, allowing an improvement in extractions by halving the time. Thus, this study demonstrated that saffron tepals can be dried maintaining their quality and that green extractions can be adopted to obtain high yields of valuable antioxidant phytochemicals, meeting the requirement for a sustainable biorefining.

Saffron is a well-known spice, produced for a long time, mainly in the Mediterranean area. In the last few years, saffron has been seen as an alternative crop for the diversification of agricultural production and a new source of income, due to its high price, including in Alpine areas. Apart from the spice, constituted by the stigmas, saffron production provides a high amount of fresh tepals, which have so far been considered agricultural waste. Recently, studies on the composition of saffron tepals have been revealing their potential as a rich source of bioactive compounds. In this study, we evaluated the productive traits and the quality of the spice of saffron cultivated in open fields in the north western Italian Alps, for 2 years. In addition, in order to valorize the crop residues, we evaluated the bioactive compound content in tepals by using maceration and ultrasound assisted extraction with different rates of water and methanol as solvents. Higher yields in spice were obtained in the second year of cultivation. However, in both years, the spice had a high quality (ISO 3632), and a very high total phenolic content and antioxidant activity. Thirteen bioactive compounds were identified, including flavonols, cinnamic acids, benzoic acids, catechins, and vitamin C, with few differences between sites and year of cultivation. In tepals, the extraction method and the solvent used influenced the evaluated parameters, i.e., total phenolics and total anthocyanins content, antioxidant activity, and the amount of the four phenolic compounds found (hyperoside, rutin, ellagic acid, and epicatechin). Overall, this study revealed that both saffron spice and its by-product, the fresh tepals, produced in the north western Italian Alps can be considered a source of bioactive compounds with nutraceutical properties, having an antioxidant capacity that is often similar or higher than those of some vegetables and fruits.