The peel essential oil (PEO) of sweet orange is used for flavoring liquors or foods and in the perfumery and cosmetics industry. The fruit maturity stage can modify the essential oil composition and aromatic properties, but little information is available on the evolution of PEO during the entire time set of fruit development. In this study, the yield, chemical composition and aromatic profile over the three phases of orange development were monitored. Four fruit traits (peel color, weight, acidity and sweetness) were recorded to characterize fruit development. Fruits of two sweet orange cultivars were sampled every two weeks from June to May of the next year. PEO was obtained by hydrodistillation and analyzed by gas chromatography coupled with a flame ionization detector (GC-FID). Compounds were identified with GC coupled with mass spectrometry (GC/MS). Ten expert panelists using the descriptor intensity method described the aromatic profile of PEO samples. The PEO composition was richer in oxygenated compounds at early fruit development stages, with an aromatic profile presenting greener notes. During fruit growth (Phases I and II), limonene’s proportion increased considerably as a few aliphatic aldehydes brought the characteristic of orange aroma. During fruit maturation (from November to March), the PEO composition and aromatic profile were relatively stable. Later, some modifications were observed. Regardless of the fruit development stage, the two sweet oranges presented distinct PEO compositions and aromatic profiles. These results constitute a temporal reference for the chemical and aromatic evolution of sweet orange PEO in the fruit development process under Mediterranean conditions. During the first two phases of fruit development, many changes occur in the PEO composition and aroma, suggesting that their exploitation could create new products.

The cosmetic and fragrance industry largely exploits citrus essential oils (EOs) because of their aromatic properties. EO compositions are complex and differ between fruit pericarp (PEO) and leaf (LEO). Citrus fruit grow in many countries under very different climates. Seventeen citrus cultivars were selected and their similarities between the two collections were verified by SSR (Single Sequence Repeat) and InDel (Insertion and Deletion) markers to assess the effects of the environment and cultivation practices on the EO yield and composition. LEOs and PEOs were extracted by water distillation and analyzed by GC-MS. PEO yields were generally higher in Corsica than in Bahia, especially in the citron family. PEOs in this family were richer in limonene in Bahia than in Corsica while, conversely, neral, geranial and derivatives were present in a higher proportion in Corsican varieties. A few minor components were site-specific, such as nookaton, a pummelo-specific compound that was not present in grapefruit cultivated in Bahia. If climate change over the last 20 years has not affected the PEO composition in Corsica, the contrasted environmental conditions and cultural practices between Bahia and Corsica could possibly explain the EO variations.

Citrus trees originated in an extensive area covering Asia (from India to the north of China) and Oceania (Queensland, Australia). The genus Citrus is defined by two different classification systems: Tanaka’s, with 156 species, and Swingle’s, with only 16 species. However, these two systems often contradict each other due to the overall sexual compatibility between the Citrus species and the frequent occurrence of apomixes (due to nucellar polyembryony), which leads many taxonomists to consid...

The Papeda Citrus subgenus includes several species belonging to two genetically distinct groups, containing mostly little-exploited wild forms of citrus. However, little is known about the potentially large and novel aromatic diversity contained in these wild citruses. In this study, we characterized and compared the essential oils obtained from peels and leaves from representatives of both Papeda groups, and three related hybrids. Using a combination of GC, GC-MS, and ¹³C-NMR spectrometry, we identified a total of 60 compounds in peel oils (PO), and 76 compounds in leaf oils (LO). Limonene was the major component in almost all citrus PO, except for C. micrantha and C. hystrix, where β-pinene dominated (around 35%). LO composition was more variable, with different major compounds among almost all samples, except for two citrus pairs: C. micrantha/C. hystrix and two accessions of C. ichangensis. In hybrid relatives, the profiles were largely consistent with their Citrus/Papeda parental lineage. This high chemical diversity, not only among the sections of the subgenus Papeda, but also between species and even at the intraspecific level, suggests that Papeda may be an important source of aroma diversity for future experimental crosses with field crop species.

Rootstock is widely used for the cultivation of citrus fruits because it brings resistance or tolerance to diseases or environmental constrains and modulates the fruit quality. Polyploidization is a widespread improvement strategy in citrus. The objective was to evaluate the effect of rootstock and ploidy level on the composition of essential oils. Two trials were conducted, one displaying a ‘Navelina’ orange grafted on three rootstocks and a second combining two ploidy levels (di and tetraploid) of scion (‘Pineapple’ orange) and rootstock (‘Carrizo’ citrange). The composition of peel essential oil (PEO) was analyzed by gas chromatography coupled with mass spectrometry, and a panel of experts analyzed its flavor variation with a triangle test approach. The rootstock influenced the yield and composition of the orange PEO, with a low impact on flavor. Neither the rootstock nor the scion ploidy level affected the PEO yield. Only the tetraploid level of the scion significantly modified the PEO composition, reducing the oxygenated compound fraction. Sensitive significant differences were detected between the reference sample (diploid scion–diploid rootstock) and the three other combinations. These results suggest that for the profiling of an aromatic flavor, the rootstock is a key element as is the ploidy level of the scion.

Sour oranges (Citrus aurantium L.) are well known in the processing and cosmetics industries for the aromatic properties of their essential oils. Intercultivar genetic and aromatic diversity is not well documented. The objective of this study was to evaluate the impact of morphological selection and genetic mechanisms of varietal diversification (mutation or hybridization) on the aromatic and odor variability of sour orange essential oils. Forty-five sour orange accessions from INRAE-CIRAD citrus Biological Resources Center (France) were assessed for ten simple sequence repeat (SSR) and 54 single nucleotide polymorphism (SNP) markers, nine morphochemical fruit traits and with the aromatic components of leaf and peel essential oils. Thirty-nine sour oranges displayed no intercultivar molecular polymorphism and six genotypes originated from interspecific hybridizations involving sour orange, citron, pummelo or mandarin. The peel essential oil (PEO) diversity was low, in accordance with the genetic diversity. The predominance of limonene (>90%) prevents any possible correlation to be made between the composition and the variation in sensory profiles detected by panelists. Few compounds in the leaf essential oil (LEO), such as linalool, linalyl acetate, α-terpineol and geraniol were significantly different across sour oranges varieties. The morphological fruit attributes mainly used in varietal selection differed highly across the main genetically identical group of sour orange accessions. These results confirm that mutation can generate variability in aromatic compounds and aromas and that their exploitation requires an improvement in characterization processes.