The dried stigmas of Crocus sativus, commonly known as saffron, are consumed largely worldwide because it is highly valuable in foods and has biological activities beneficial for health. Saffron has important economic and medicinal value, and thus, its planting area and global production are increasing. Petals, which are a by-product of the stigmas, have not been fully utilized at present. We compared the metabolites between the stigmas and petals of C. sativus using a non-targeted metabolomics method. In total, over 800 metabolites were detected and categorized into 35 classes, including alkaloids, flavonoids, amino acids and derivatives, phenols and phenol esters, phenylpropanoids, fatty acyls, steroids and steroid derivatives, vitamins, and other metabolites. The metabolite composition in the petals and stigmas was basically similar. The results of the study showed that the petals contained flavonoids, alkaloids, coumarins, and other medicinal components, as well as amino acids, carbohydrates, vitamins, and other nutritional components. A principal components analysis (PCA) and an orthogonal partial least-squares discriminant analysis (OPLS-DA) were performed to screen the different metabolic components. A total of 339 differential metabolites were identified, with 55 metabolites up-regulated and 284 down-regulated. The up-regulated metabolites, including rutin, delphinidin-3-O-glucoside, isoquercitrin, syringaresinol-di-O-glucoside, dihydrorobinetin, quercetin, and gallocatechin, were detected in the petals. The down-regulated metabolites were mainly glucofrangulin B, acetovanillone, daidzein, guaiazulene, hypaphorine, indolin-2-one, and pseudouridine. KEGG annotation and enrichment analyses of the differential metabolites revealed that flavonoid biosynthesis, amino acids biosynthesis, and arginine and proline metabolism were the main differentially regulated pathways. In conclusion, the petals of C. sativus are valuable for medicine and foods and have potential utility in multiple areas such as the natural spice, cosmetic, health drink, and natural health product industries.

Saffron (Crocus sativus L.) is an important medicinal crop with high economic value in the world. Due to its growth patterns and environmental requirements, Chinese enterprises employ two-stage cultivation for saffron. However, the relationship between corm size and flowering characteristics in this cultivation remains understudied. This study investigated the correlation between corm size and flowering characteristics, including flower count, stigma yield, and mass concentration percentage of crocin and picrocrocin, as well as physiological differences in corm of different sizes indoors. Results indicated that there was a significantly positive correlation with corm size and flower number (r = 0.98) and stigma yield (r = 0.98). Additionally, a positive correlation was observed between corm size and mass concentration percentage of crocin (r = 0.54), whereas no correlation existed between corm size and mass concentration percentage of picrocrocin (r = 0.19). Significant variations in soluble protein, soluble sugar, starch, and hormone (ZR, IAA, GA₃, ABA) contents were noted in this study. Larger corm sizes had higher contents of soluble protein, soluble sugar, and starch. Meanwhile, starch content mostly had a decreasing trend indoors, which provides sufficient energy and nutrients for flower bud differentiation. ZR and IAA showed greater responsiveness, and increased levels of ZR and IAA potentially promote flower bud differentiation. This study provides theoretical guidance for field management optimization, yield improvement, and quality control of saffron in Chinese two-stage cultivation.

This study evaluated the effects of three storage temperatures (4 °C, −20 °C, −80 °C) on metabolites in saffron stigmas after one year of storage using non-targeted metabolomics based on LC-MS and GC-TOF-MS. Lower storage temperatures better preserved chemical activity, and different metabolites markedly included capsiate, sarmentine, sesamolinol, nobiletin, prostaglandin F1α, vanillin, and α-ketoglutaric acid. Amino acid-centered pathways, including alanine, aspartate, glutamate, and phenylalanine metabolism, constitute core temperature-responsive modules. Aspartic acid and alpha-ketoisovaleric acid exhibited strong correlations with key quality indicators crocin and picrocrocin. The −80 °C treatment significantly yielded the highest retention of crocin and picrocrocin, with their contents being 21.46% and 31.25% higher, respectively, than at 4 °C. −80 °C is recommended for long-term storage, whereas −20 °C is suitable for household use. This study provides a theoretical foundation and practical guidance for saffron preservation for producers and consumers.