Comparative Volatilomic Profile of Three Finger Lime (Citrus australasica) Cultivars Based on Chemometrics Analysis of HS-SPME/GC–MS Data

Abstract

Finger lime is receiving growing attention as an ingredient of gastronomic preparations of haute cuisine for its delicious flavor and fragrance and for its appealing aspect. Volatile compounds play a crucial role in determining the organoleptic characteristics of the fruit and its pleasantness for consumers. The aim of the present study was to investigate the volatile profiles by headspace solid phase micro-extraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC–MS) in the peel and, for the first time, in the pulp of three Australian finger lime cultivars grown in Sicily (southern Italy): Pink Pearl, Sanguinea, and Faustrime, allowing to overall identify 84 volatile organic compounds (VOCs). The analytical data showed that the three cultivars were characterized by distinct volatile chemotypes: limonene/sabinene/bicyclogermacrene in the Pink Pearl, limonene/γ-terpinene/bicyclogermacrene in the Sanguinea, and limonene/β-phellandrene/γ-terpinene in the Faustrime. Moreover, some volatiles, found exclusively in one cultivar, could be considered potential markers of the individual cultivar. PCA allowed us to clearly discriminate the samples into three clusters: the first related to the Sanguinea peel, the second to the Faustrime peel, and a third group associated with the Pink Pearl peel along with the pulp of the three cultivars. Accordingly, the VOCs that mostly contributed to the differentiation of the three finger lime cultivars were also identified. Among them, D-limonene, sabinene γ-terpinene, α-pinene, α-phellandrene, β-myrcene, p-cymene, linalool, δ-elemene, ledene, bicyclogermacrene β-citronellol, α-bergamotene, α-caryophillene, and β-bisabolene, have been previously reported to exhibit important biological activities, suggesting that these cultivars, in addition to possessing unique volatile profiles, can show promise for several applications in pharmaceutical and food industry, namely for development of functional foods.

LC-MS and GC-MS Data Fusion Metabolomics Profiling Coupled with Multivariate Analysis for the Discrimination of Different Parts of Faustrime Fruit and Evaluation of Their Antioxidant Activity

“…In particular, citronellal was the most relative abundant monoterpene hydrocarbon detected in the peel (23.47%), followed by limonene, citronellol, and linalyl acetate (12.99%, 10.65%, and 7.65% respectively). An inverse citronellal/limonene ratio was registered for the peel of the investigated cultivar compared to the studies reported in the literature [ 5 , 8 ]. Differently, the pulp of the fruit highlighted the main content of linalyl acetate and limonene (18.23% and 11.40%, respectively), along with a higher content of trans -piperitol (1.83%) conferring the typical hint of paper to the culinary used pulp, compared to the peel, in contrast with Cioni et al, 2022 [ 9 ].…”

“…Monoterpenes were the most abundant VOCs identified, followed by sesquiterpenes. Generally, a citronellal/limonene/linalyl acetate chemotype can be considered for the investigated cultivar, highlighting differences in abundance ratios with previous studies [ 5 , 9 ]. The occurrence of linalyl acetate was reported for the first time in Faustrime.…”

“…The peels are used as a fresh spice to flavor dishes, while other parts (seeds and albedo) are usually discharged despite the high price of the fruit. The distinctive aroma of the fruit could be determined by the unusual volatile constituents in Citrus , such as limonene, β-phellandrene, and γ-terpinene, as reported in the Faustrime cultivar from Sicily [ 5 ]. Moreover, the occurrence of citronellal is reported as a major compound along with limonene, β-phellandrene, and γ-terpinene in a cultivar from southern Italy [ 3 ].…”

The genome of Citrus australasica reveals disease resistance and other species specific genes

“…C. australasica has a high natural genetic diversity with a large number of VOC in different cultivars having β-citronellol, citronellal, γ-terpinene, and limonene as the predominant constituents [ 68 , 69 ]. A previous study has shown that C. australasica is rich in VOC such as citronellal, nonanal, β-phellandrene, δ-elemene, α-farnesol, β-farnesol which can act as antimicrobial agents to provide the plants with resistance against HLB.…”

D-Limonene: Promising and Sustainable Natural Bioactive Compound

“…The extraction of high-value chemical substances from fruit peels can not only effectively alleviate this problem, but can also achieve sustainable development and promote economic cycles [31]. D-limonene is widely present in essential oils extracted from the peels and leaves of natural plants and its content depends on the plant species and cultivar [32][33][34][35]; notably, D-limonene is present in large amounts (up to 98.54%) in citrus (Table 1). Natural plant extraction of D-limonene can be performed using organic solvent extraction, new bio-based solvent extraction, and natural deep eutectic solvent extraction [36][37][38].…”