柠檬苦素主要存在的柑橘类型果肉

… In this study, seeds were not removed during the preparation of pulp samples. Because of the high content of limonin in seeds, the content of limonin detected in pulp samples with …

… and Finisher Pulp. Commercially manufactured, dried (10% moisture) Valencia orange peel residue (dried citrus pulp) was comminuted in a Wiley mill to 1 mm particle size and finely …

The increased consumption of fruits, vegetables, and whole grains contributes to the reduced risk of many diseases related to metabolic syndrome, including neurodegenerative diseases, cardiovascular disease (CVD), diabetes, and cancer. Citrus, the genus Citrus L., is one of the most important fruit crops, rich in carotenoids, flavonoids, terpenes, limonoids, and many other bioactive compounds of nutritional and nutraceutical value. Moreover, polymethoxylated flavones (PMFs), a unique class of bioactive flavonoids, abundantly occur in citrus fruits. In addition, citrus essential oil, rich in limonoids and terpenes, is an economically important product due to its potent antioxidant, antimicrobial, and flavoring properties. Mechanistic, observational, and intervention studies have demonstrated the health benefits of citrus bioactives in minimizing the risk of metabolic syndrome. This review provides a comprehensive view of the composition of carotenoids, flavonoids, terpenes, and limonoids of citrus fruits and their associated health benefits.

… terms of its biochemical content (limonin, secondary metabolites), … Despite its NV, limonin an aglycones and glycosides are … bioactive functions of the limonin as therapeutic applications. …

… , r, were relatively low, averaging for all dates 0.48 for limonin and Brix, 0.56 for limonin and percent acid, and 0.62 for limonin and Brix/acid ratio. When regression equations were …

… limonin … pulp was separated from the juice using finisher. Orange juice was first heated to 95-98oC using heat exchanger to pasteurization and to convert all limonin precursors to limonin…

… The term ‘limonoid’ was given after limonin, the first bitter component identified in citrus … , deacetylnomilin, limonin, and nomilin. Lemon peels and pulp contained two components of …

Citrus limon (lemon) is important in pharmaceutical, restorative, and culinary (solid nourishment). It has uncommon properties and distinctive chemical compositions. The advantageous organic action of C. limon is decided by its tall substance of phenolic compounds, basically flavonoids (e.g., diosmin, hesperidin, limonin) and phenolic acids (e.g., ferulic, synaptic, p-hydroxybenzoic acids). The fundamental oil contains bioactive monoterpenoids such as D-limonene, β-pinene, and γ-terpinene. As of late, deductively demonstrated restorative exercises of C. limon incorporate anti-inflammatory, antimicrobial, anticancer, and antiphrastic exercises. This considers the point of utilizing liquid chromatography-mass spectrometry (LC/MS) to examine the distinctive chemical components in different parts of Jordanian lemon. Lemon peels have the most extreme substance of hesperidin.

… in the flesh portion is important from a juice-processing viewpoint because LARL that enters the juice during processing is converted to limonin, … to reduce the LARL content of citrus fruit. …

… This natural limonoid debittering process occurring in citrus fruit has been known for … limonin and nomilin in flesh extracts. System b was used for the analysis of deacetylnomilin in flesh …

… citrus fruit are synthesized from nomilin or deacetylnomilinic acid translocated from the phloem of stems.In our study, limonin … of limonin and nomilin in different fruit tissues of four Citrus …

… peel, seed and flesh of the citrus fruits. The other bitter component, limonin, is primarily in … The initiation of this work stems from the fact that prewashing of citrus fruits with hot water is …

… Limonin is the major limonoid found in most citrus fruit juices and is therefore the major cause of delayed bitterness. The taste threshold of limonin … in the peel and flesh tissue (10,68,73). …

… peel has 2 to 6 times the carotenogenic capacity of the endocarp (pulp); thus 70% of the fruit … of bitter components such as naringin and limonin. Reduction in the activity of the heat …

Abstract Bitterness, which is mainly attributed to limonoids, seriously affects the taste of pomelo fruits and hinders their competitiveness in the market. Therefore, a high-performance liquid chromatography method was developed for simultaneous isolation and determination of limonin, nomilin, and limonin glucoside contents in pomelo fruit, and the method showed good precision (RSD ≤ 2.85%), repeatability (RSD ≤ 3.37%) and high sample recovery rate (95.8%–99.7%). Four pomelo varieties were used to investigate the accumulation and distribution of limonoids in different stages of fruit development and in different plant tissues and varieties, as well as to reveal the synthesis mechanism and provide a basis for the utilisation of pomelo resources in different industries. Results showed that flavedo was the tissue richest in limonoids, and the maximum limonoid content could reach 5959 μg/g fresh weight. During fruit growth and development, the limonin and nomilin contents in juice sacs and albedo first increased and then decreased. Although there were some fluctuations, the limonin and nomilin contents in the flavedo generally showed a decreasing trend with fruit development. Our investigation of the LGT gene expression pattern provided the basis for exploring natural debittering mechanisms in pomelo. Expression of the LGT gene was positively correlated with limonin glucoside content.

Delayed bitterness causes severe economic loss in citrus juice industry worldwide, which is mostly due to the formation of limonoid compounds, especially limonin, in juice. In this study, effects of postharvest time of fruits, heat treatment, pH and filtration of juice on limonin content in Newhall navel orange (Citrus sinensis Osbeck cv. Newhall) juice were investigated. Our research indicated for the first time that: (1) limonin content in juice would gradually increase to a maximal level and then remained almost constant thereafter as storage time going on, whereas the maximum constant value (MCV) of limonin content in juice significantly (p < 0.05) decreased with the increment of postharvest time of fruits being juiced; (2) heat treatment and acidification of juice only speeded up the formation of limonin to the maximal level while without changing the MCV of limonin content; (3) the juice after filtration exhibited much lower MCV of limonin content compared with the unfiltered one. These experimental observations might not only provide useful information for the development of new debitterness method for navel orange juice, but also strongly support the acid-promoted delayed bitterness mechanism, suggesting the formation of delayed bitterness might primary due to the acid-promoted rather than the enzyme-catalyzed lactonization of limonoate A-ring lactone (LARL) to produce limonin in juice of navel orange.

… limonin and nomilin in the sample from citrus fruit tissues, we compared our sample with the standard limonin … little lower than that of a 50 μg limonin standard, but it was markedly higher …

… and one of the citrus species because it contains large amounts of limonin, nomilin and … of Fortunella species with Citrus species both contain the calamin and limonin limonoids. …

Citrus limonoids (CLs) are a group of highly oxygenated terpenoid secondary metabolites found mostly in the seeds, fruits and peel tissues of citrus fruits such as lemons, limes, oranges, pumellos, grapefruits, bergamots, and mandarins. Represented by limonin, the aglycones and glycosides of CLs have shown to display numerous pharmacological activities including anticancer, antimicrobial, antioxidant, antidiabetic and insecticidal among others. In this review, the chemistry and pharmacology of CLs are systematically scrutinised through the use of medicinal chemistry tools and structure-activity relationship approach. Synthetic derivatives and other structurally-related limonoids from other sources are include in the analysis. With the focus on literature in the past decade, the chemical classification of CLs, their physico-chemical properties as drugs, their biosynthesis and enzymatic modifications, possible ways of enhancing their biological activities through structural modifications, their ligand efficiency metrics and systematic graphical radar plot analysis to assess their developability as drugs are among those discussed in detail.

… Some of these areas produce citrus on a … species of Citrus, each of which contains different cultivars which are grown in different areas of the world depending upon the climate. Citrus …

… Inhibition of P-glycoprotein activity by limonin and other secondary metabolites from Citrus species in human colon and leukaemia cell lines. Eur J Pharmacol. 626: 139–145 (2010). …

… process in different Citrus species has not yet been fully characterized. Limonin glucoside is the … LGTase is a key factor regulating limonin glucoside accumulation in fruit. The observed …

… Citrus species are a rich source of several bioactive compounds such as citric acid, ascorbic acid, … Three aglycones such as limonin, nomilin and obacunone were purified from Citrus …

To investigate the distribution pattern of bioactive components and their correlations between citrus varieties, we thoroughly analyzed secondary metabolites (including flavonoids, phenolic acids, carotenoids, and limonoids) in the peel and pulp of 11 citrus varieties from the production area of Zhejiang. Citrus peels accumulated metabolites far more than the pulp, and the accumulation varied significantly between species. Flavonoids were the most abundant compounds, followed by phenolic acids, with carotenoids and limonoids being far less abundant than the first two, but limonoids were more abundant than carotenoids. Hesperidin was the main flavonoid in most varieties, but cocktail grapefruit and Changshanhuyou contained naringin, with Ponkan having the most abundant polymethoxylated flavones (PMFs). The major components of phenolic acids, carotenoids, and limonoids were ferulic acid, β-cryptoxanthin, and limonin, respectively. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) indicated that these components were mostly correlated with each other, and these citrus varieties could be categorized into four groups by pulp and three groups by peel. The obtained results filled the data gap for secondary metabolites from local citrus and could provide data references for citrus resource utilization, selection and breeding of superior varieties, and other research.

Abstract Citrus fruits are consumed in large quantities worldwide due to their attractive aromas and taste, as well as their high nutritional values and various health-promoting effects, which are due to their abundance of nutrients and bioactives. In addition to water, carbohydrates, vitamins, minerals, and dietary fibers are important nutrients in citrus, providing them with high nutritional values. Citrus fruits are also rich in various bioactives such as flavonoids, essential oils, carotenoids, limonoids, and synephrines, which protect from various ailments, including cancer and inflammatory, digestive, and cardiovascular diseases. The composition and content of nutrients and bioactives differ significantly among citrus varieties, fruit parts, and growth stages. To better understand the nutrient and bioactive profiles of citrus fruits and provide guidance for the utilization of high-value citrus resources, this review systematically summarizes the nutrients and bioactives in citrus fruit, including their contents, structural characteristics, and potential health benefits. We also explore the composition variation in different citrus varieties, fruits parts, and growth stages, as well as their health-promoting effects and applications.

Citrus hybrids with Poncirus trifoliata L. Raf. introgression have gained interest due to their tolerance to Huanglongbing (HLB), a devastating disease for Florida citrus agriculture. While these hybrids inherit disease tolerance from P. trifoliata, they sometimes also suffer from undesirable off-flavors.A selection of thirteen genotypes were harvested over the 2020-2021 and 2021-2022 seasons. Their juices were evaluated by a trained sensory panel and were comprehensively analyzed for their chemical makeup, including soluble solids content (SSC), titratable acidity (TA), volatiles, flavonoids and limonoids.Overall, along with the commercial orange cultivars ‘Valencia’ and ‘Hamlin’, the HLB-tolerant Poncirus hybrid ‘US SunDragon,’ and the mandarin hybrids Sugar Belle®, FF-5-51-2, and ‘US Superna’ had positive citrus flavor quality. Esters, some sesquiterpenes, along with flavonoids, eriocitrin and quercetin-3-(3R-glucosylrutinoside), were positively correlated with orange flavor while β-ionone and eucalyptol were highly abundant in the mandarins. The flavonoid linarin, was more abundant in Poncirus hybrids with off-flavors than in the Poncirus hybrid ‘US SunDragon’, having high orange flavor. Two mandarin hybrids, FF-5-6-36 and FTP-6-32-67, were not bitter at harvest, but the juice exhibited delayed bitterness after storage at -20°C, which was associated with significant increases of limonin, nomilin, naringenin, and prunin. Interestingly, during freezer storage, a newly identified flavonoid in citrus, tricin-C-hexoside, increased dramatically across all of the genotypes. The identification of disease-tolerant hybrids with satisfactory flavor quality at juicing as well as after storage where delayed bitterness may develop, has great significance for future breeding efforts for fresh fruit or for use in stand-alone juice/juice blends.

Many citrus varieties are hybridized to improve their quality and to overcome the effects of climate change. However, there is limited information on the effect of the chemical profiles of hybrid varieties on their quality. In this study, we analyzed 10 citrus varieties and evaluated the correlation with their general characteristics and antioxidant activities. Chemical profiles, including the contents of sugars, organic acid compounds, flavonoids, limonoids, and carotenoids, which are related to taste, color, and health benefits, were significantly different depending on the citrus varieties, leading to different antioxidant capacities and general quality parameters. Based on these data, the correlations were investigated, and 10 citrus varieties were clustered into four groups—Changshou kumquat and Jeramon (cluster I); Setoka (cluster II-1); Natsumi, Satsuma mandarin, and Navel orange (cluster II-2); Kanpei, Tamnaneunbong, Saybyeolbong, and Shiranui (cluster II-3). Moreover, a metabolomic pathway was proposed. Although citrus peels were not analyzed and the sensory and functional qualities of the citrus varieties were not investigated in this study, our results are useful to better understand the relationship between citrus quality and metabolite profiles, which can provide basic information for the development and improvement of new citrus varieties.

Bitterness and off-flavors are problematic in some citrus genotypes, particularly Citrus hybrids with Poncirus trifoliata in their pedigrees that have shown tolerance to the devastating citrus greening disease. Comprehensive chemical profiling combined with sensory analysis of bitterness were used to determine bitter compounds in citrus juice. A selection of genotypes including orange, grapefruit, pummelo, tangelo, mandarin hybrids with and without P. trifoliata in their pedigrees, as well as pure P. trifoliata, were analyzed due to their broad range in bitterness intensity. Widely targeted LC-MS/MS analysis of flavonoids and limonoids confirmed the role of limonin, nomilin, neohesperidin and poncirin in bitterness perception. Other flavonoids, mainly rhoifolin, apigenin, and tricin also correlated with bitterness. Notably, rhoifolin was more strongly correlated with bitterness than the previously known bitter compounds. Identifying the compounds that contribute to bitterness in citrus is a crucial first step for future breeding efforts aimed at reducing these compounds biosynthetically.

The genus Citrus contains a vast range of antioxidant metabolites, dietary metabolites, and antioxidant polyphenols that protect plants from unfavorable environmental conditions, enhance their tolerance to abiotic and biotic stresses, and possess multiple health-promoting effects in humans. This review summarizes various antioxidant metabolites such as organic acids, amino acids, alkaloids, fatty acids, carotenoids, ascorbic acid, tocopherols, terpenoids, hydroxycinnamic acids, flavonoids, and anthocyanins that are distributed in different citrus species. Among these antioxidant metabolites, flavonoids are abundantly present in primitive, wild, and cultivated citrus species and possess the highest antioxidant activity. We demonstrate that the primitive and wild citrus species (e.g., Atalantia buxifolia and C. latipes) have a high level of antioxidant metabolites and are tolerant to various abiotic and biotic stresses compared with cultivated citrus species (e.g., C. sinensis and C. reticulata). Additionally, we highlight the potential usage of citrus wastes (rag, seeds, fruit peels, etc.) and the health-promoting properties of citrus metabolites. Furthermore, we summarize the genes that are involved in the biosynthesis of antioxidant metabolites in different citrus species. We speculate that the genome-engineering technologies should be used to confirm the functions of candidate genes that are responsible for the accumulation of antioxidant metabolites, which will serve as an alternative tool to breed citrus cultivars with increased antioxidant metabolites.

… Hesperidin, narirutin, didymin, limonin and vitamin C were obtained commercially from … such as citrus cultivar, tree age, harvest time, bacterial infection level and growing condition. …

BACKGROUND Citrus aurantium L. (Aurantii fructus) is a multi-purpose citrus fruit with high medicinal and nutritional value, but currently there is no data that can be used to investigate its appropriate harvest time to obtain high-quality citrus bioactive ingredients. RESULTS Phytochemicals and levels of the main bioactive ingredients were investigated by UHPLC-ESI-Q-TOF/MS. The contents of flavanones, polymethoxyflavones, coumarins, synephrine, and limonin in citrus fruit were analyzed at different harvest periods, and significant differences ranging from 0.03 ± 0.01 to 116.26 ± 40.20 g kg-1 (DW) were shown. These compounds were present in higher amounts in June and then decreased gradually, while biomass accumulation of most of them showed an increasing tendency along the harvest times. The H2 O2 -induced RIN-m5F cells model was employed to evaluate their antioxidant capacity. Citrus fruit harvested from June 11 to July 7 possessed an excellent antioxidant capacity by inhibiting the intensity of intracellular reactive oxygen species (ROS) (p < 0.01) and improving superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) activities (p < 0.01). In addition, chemical compositions and antioxidant capacities of citrus leaves, stems, and roots were evaluated, and these showed great variation compared with citrus fruits. Multivariate statistical analysis indicated that harvesting time was related closely to the phytochemical contents and antioxidant capacity. CONCLUSION Citrus fruit can be appropriately harvested from June to early July when the levels of bioactive ingredients and antioxidant activity reach higher values. This research provides practical information for producing high-quality citrus products. This article is protected by copyright. All rights reserved.

The increasing attention on the impact of food on human and environmental health has led to a greater awareness about nutrition, food processing, and food waste. In this perspective, the present work deals with the investigation of the chemical non-volatile and volatile profiles of two Citrus-based products, produced through a conscious process, using Citrus peels as natural gelling agents. Moreover, the total polyphenol content (TPC) and the antioxidant properties were evaluated, as well as their sensorial properties. Chemical and antioxidant results were compared with those of Citrus fresh fruits (C. reticulata, C. sinensis, and C. limon). Concerning the non-volatile fingerprint, the two samples showed a very similar composition, characterized by flavanones (naringenin, hesperetin, and eriodyctiol O-glycosides), flavones (diosmetin and apigenin C-glucosides), and limonoids (limonin, nomilinic acid, and its glucoside). The amount of both flavonoids and limonoids was higher in the Lemon product than in the Mixed Citrus one, as well as the TPC and the antioxidant activity. The aroma composition of the two samples was characterized by monoterpene hydrocarbons as the main chemical class, mainly represented by limonene. The sensorial analysis, finally, evidenced a good quality of both the products. These results showed that the most representative components of Citrus fruits persist even after the transformation process, and the aroma and sensorial properties endow an added value to Citrus preparations.

… factors affecting the limonin content of grapefruit juice (2) the effect of limonin content on … limonin content in ajficting grapejruit juice flavour and (4) methods for reducing limonin in citrus …

… can be mechanistically rationalized to proceed through glucoside hydrolysis of limonin glucoside followed by lactonization to form limonin and its C-17 epimer (epilimonin) (Figure 3 ). …

Citrus is the prime fruit crop cultivated worldwide, and well known for nutritional, organoleptic and nutraceutical related properties. Citrus fruits are rich source of several secondary metabolites (SM), like flavonoids, ascorbic acid, polyphenols, carotenoids, terpenoids, and limonoids. Citrus have evolved a multitude of defense mechanisms to enhance their resilience against biotic and abiotic stresses, with SM playing a critically significant role in plant survival, defence, adaptability, and reproduction. Among all biotic stresses, Huanglongbing (HLB, citrus greening) is the major constraint to limits citrus production. HLB is a destructive disease caused by Candidatus Liberibacter spp. HLB has been found in nearly all cultivated varieties which causes the losses by affecting fruit development, quality, tree vigor, and production. This review gives brief highlights on these compounds and discussed their function in citrus defence mechanism, role in fruit maturation, metabolic responses against Huanglongbing (HLB), and hormone signalling pathways. Majority of the amino acids, flavanone, terpenes, flavone, flavonoids, aldehyde, volatile compounds, and monoterpenes in HLB-tolerant cultivars were much higher than susceptible. Various metabolic studies indicated that specific metabolites play a crucial role in limiting the spread and multiplication of the pathogens. Additionally, these metabolic signatures have the potential to be developed as markers for tolerance against HLB. Advanced tools like CRISPR/Cas9, metabolomics, and synthetic biology should be employed to validate the candidate genes involved in enhancing the production of compounds associated with HLB tolerance. The identified genes or SM could serve as valuable targets for citrus breeding, providing long-term solutions to combat HLB disease.

The effect of fruit size and harvesting of Thai tangerine fruit (Citrus reticulata, Blanco) at different growth stages, 8–12 months after fruit set, on the distribution of limonin in whole fruit as well as in the individual fruit parts and extracted juice was investigated. The highest limonin concentration was observed in seed, followed by albedo, flavedo, segment membrane and juice sacs in decreasing order. The limonin concentration in juice as well as in whole fruit was decreased when fruit was harvested 8–12 months of fruit set. Increasing harvesting time from 8 to 12 months showed corresponding decreases in the amount of limonin in flavedo, albedo and seed. There was a decrease in titrable acidity and increase in total soluble solid and total soluble solid/titrable acidity ratio of juice with a later than normal harvesting time. However, fruit size showed no effect on limonin content and other properties of juice extracted from tangerine.

… limonin was presented in entire oranges throughout the mature period. The concentration of limonin was two times in peel than in juice sacs. … determination of limonin in citrus juices by …

AbstractThis review discusses different facets of the subject of bitterness in, and debittering of, citrus juices. For this purpose, the tone is set up by giving an account of the biochemical properties of naringin, responsible for “immediate” bitterness, and of limonin, responsible for “delayed” bitterness. Their structures are ellucidated, and enzymes participating in their catabolic pathways are assigned. Thereafter, methods used to determine bitterness, based on the principles of colorimetry, chromatography, and biochemistry, are discussed, including their advantages and disadvantages. Finally, different physicochemical and biotechnological approaches for debittering are discussed.

… A parallel story unfolds with compounds like limonin and naringin, the bittersome duo found in grapefruit and pomelo. Their bitter contributions, though objectionable to some palates, …

Abstract Limonin is a biomolecule which is responsible for the bitter taste in citrus fruits such as oranges, grapes etc. The abnormally high level of limonin is indicative of citrus greening disease which results in stunted tree growth and affects fruit quality in terms of nutritional value, taste, texture and aroma. Therefore, quantification and detection of limonin is crucial for an early management of citrus greening disease to save the multibillion dollar citrus industry. To this end, an organic electrochemical transistor (OECT) functionalized with Ceria Nanoparticles (CNPs) as transducer has been developed to detect ultralow concentration of limonin. The device exhibited high sensitivity (detection limit: 10 nM) and selectivity towards limonin with response time in seconds. The detection is attributed to the switching of Ce3+ to Ce4+ at the gate electrode which decreases the overall effective gate voltage resulting in an increase in the output current. The increase in output current was observed in transfer characteristics as well as time-current curve. In-situ spectro-electrochemical studies were also performed to analyse the change in oxidation state of CNPs in the presence of limonin. This novel biosensor successfully detected the increase in limonin in infected juice samples as compared to healthy ones with a sensitivity of ∼10 μA/μM. A rapid, easy and on-site testing tool to detect and quantify the amount of limonin for an early detection of citrus greening disease has been demonstrated for the first time.

Limonin, a highly oxygenated triterpene biomolecule of citrus fruits is responsible for delayed bitterness of its juice lowering consumer's acceptability. Hence, limonin detection is essential for appropriate debittering intrusions. A novel interdigitated capacitive sensor using magnesium silicate-poly vinyl alcohol (MgSiO3.xH2O-PVA) composite has been introduced for quantification of limonin and debittering through selective adsorption of limonin from the citrus limetta juice. The sensor showed high sensitivity of 2.392 µF/ppm and fast response time of ∼6s. The sensor enables both quantification as well as measure debittering of citrus juice showing a reduction in limonin content from 5.77 ppm to 4.29 ppm with an exposure time of 60s to the sensing material making it distinctive in comparison to other methods. The sensor's results were validated with HPLC analysis. The device is simple, low-cost and reusable which promises easy, on-site and rapid quantification and reduction of limonin content in citrus juices without having toxicity.

… juice arises from a tetracyclic triterpenoid called limonin. The limonin is produced over time from limonic acid or limonin … , which is found in the seeds and membranes of most citrus fruits. …

Naringin and limonin are the principle bitterness components of citrus juices. Our objective was to determine if the perceived bitterness in grapefruit juice could be reduced during storage through interaction with active packaging film. Storage of 10° Brix grapefruit juice at 7°C in contact with fungal-derived naringinase immobilized on cellulose acetate film reduced bitterness as perceived by a sensory panel. The films reduced naringin and limonin concentration by hydrolysis and adsorption respectively. Reduction in the naringin and limonin content of grapefruit juice by cellulose acetate films containing immobilized enzyme from 600–400 mg/l and 8.0–6.7 mg/l respectively could be detected as a reduction in bitterness by a sensory panel (p < 0.10). As the area of film (cm2)/volume of juice (ml) ratio increased from 1.1 to 3.6, the time to decrease the naringin level decreased. The reduction in naringin was not affected by agitation or holding the samples quiescently. The amount of enzyme desorbed from the film represented only 2% of the amount of enzyme immobilized in the film. The reduction in bitterness comes from direct interaction with the active packaging films. © 1998 John Wiley & Sons, Ltd.

… Concentrations of limonin and naringin in citrus juices using different HPLC methods have … Citrus juice and tissues contained 0580 µg/mL of naringin and 0-135 µg/mLof limonin (14,28…

Abstract Limonoids, a group of highly oxygenated bioactive triterpenoid components, are abundant in citrus. In the present study, a comprehensive metabolomic analysis of limonoids was performed among the flavedo, albedo, segment membrane, juice vesicles, and seeds of pummelo by using Quadrupole-Orbitrap UHPLC-MS/MS. As a result, 21 limonoids were identified in the five tissues and their MS/MS fragmentation characteristics were elucidated. Significant positive correlations were found between juice vesicles and seeds as well as between albedo and segment membranes in limonoid metabolism. Seeds contained fourteen abundant limonoids, while by contrast the flavedo only accumulated three major limonoids (limonin, casimirolide and limonin A-ring lactone). Furthermore, a series of potential biomarkers were developed for limonoid characterization in different tissues or parts. Overall, our results reveal the structural diversity of limonoids and their tissue distribution in pummelo fruit, and lay a foundation for further development and utilization of limonoid metabolites of citrus species.

Citrus fruits are recommended components of the human diet because of their enriched composition in bioactive compounds and health benefits. Among their notable components are phenols, with a special emphasis on flavonoids, limonoids, and carboxylic acids. In this research, we have carried out a spatial metabolomics analysis for the characterization of these bioactive families in three citrus fruits, namely, lemons, limes, and mandarins. Sampling was undertaken, for which the juices and three fruit tissues, namely, albedo, flavedo, and segments, were analyzed. This characterization allowed for the determination of 49 bioactive compounds in all the samples. The composition of the different extracts was correlated with the antioxidant capacity measured by the DPPH radical scavenging activity and β-carotene bleaching assays. Flavonoids, found in the albedo and flavedo at higher concentrations, were the main components responsible for DPPH radical scavenging activity. On the other hand, the combined action of flavonoids and limonoids contributed to explaining the antioxidant activity measured by the β-carotene bleaching assay. Generally, the antioxidant capacity of juices was lower than that estimated for extracts from citrus tissues.

Citrus flavor and nutritional quality are closely tied to metabolite composition, yet comparative metabolic dissection of fruit pulp traits across citrus subspecies remains insufficient. Here, we applied non-targeted LC–MS/MS metabolomics to examine chemical diversity in the fruit pulp of three representative citrus varieties: Citrus reticulata ‘Hongju 418’, Citrus aurantium ‘Changshan-huyou,’ and Citrus junos ‘Hunan Xiangcheng.’ Through differential metabolite analysis, multivariate modeling, correlation network construction, and KEGG pathway enrichment, we characterized the extent and nature of metabolic divergence among these genotypes. PCA, PLS-DA, and OPLS-DA revealed distinct metabolic clusters, underscoring strong genotype-specific variation. More than 300 differentially expressed metabolites were identified, including flavonoid glycosides, organic acids, phenolic derivatives, and limonoids. Hongju 418 was enriched in flavonoid biosynthetic pathways, Xiangcheng accumulated higher concentrations of organic and amino acids, and Huyou displayed a unique hybrid profile marked by elevated fatty acid and purine metabolism. Correlation and KEGG analyses consolidated these observations, revealing coordinated pathway-level shifts that define subspecies-specific metabolic architectures. Collectively, this work deepens current understanding of citrus pulp chemotypes and provides a robust biochemical foundation for advances in citrus breeding, quality assessment, and functional product innovation.

Ougan (Citrus suavissima Hort. et Tanaka) is valued for its distinctive sweet–bitter flavor and nutritional properties; however, tissue-resolved metabolic differences between two cultivar forms (seeded and seedless) of Ougan (C. suavissima) remains poorly understood. In this study, a comprehensive UPLC-MS/MS-based metabolomic analysis was conducted on peel (SP and NP), pulp (SF and NF), segment membrane (SM and NM) and seed tissues (SS, from seeded fruit only) of seeded and seedless Ougan fruits. A total of 1333 metabolites were annotated, with flavonoids (48.53%) and phenolics (12.25%) representing the predominant compound classes. Tissues specificity was the primary determinant of metabolic variation, with peel and segment membrane tissue showing relatively high abundance (fold change ≥ 2, |Log2FC| ≥ 1) of phenylpropanoid- and flavonoid-derived metabolites. Comparative analysis between seeded and seedless tissues revealed significant modulation of phenylpropanoid biosynthesis, flavonoid biosynthesis, phenylalanine metabolism, and related secondary metabolite pathways. Seeded tissues showed a higher relative abundance of selected flavonol glycosides (6-hydroxykaempferol-3,6-O-diglucoside), hydroxycinnamic acid derivatives, and santhocyanin-related compounds, whereas seedless tissues showed higher relative abundance of selected flavanones and malonylated flavonoid glycosides. Seeds were characterized by high limonin content, consistent with limonoid-associated bitterness chemistry. Overall, our findings provide a tissue-resolved metabolomic framework for understanding quality-associated secondary metabolite variation in mature Ougan fruit.

Citrus fruits are essential sources of food and energy and play a critical role in supplementing healthy diets. Citrus fruits contain mostly carbohydrates such as sucrose, glucose, and fructose and are good dietary fiber sources, which help prevent gastrointestinal disease and promote high circulating cholesterol. Besides, citrus fruits are also significant sources of vitamin C and various bioactive compounds. It is suggested that these components are of vital importance in improving human health due to their antioxidant properties and being converted to vitamin A. However, citrus fruit is still being used for different purposes like juice, jam, jelly, squash, pies, cake, candies, marmalades, etc. Most citrus waste materials are currently used as animal feed. Innovations are occurring in the conversion of citrus by-products into valuable commodities with the development of innovative technologies. This chapter has put up primary and secondary research findings of citrus fruits, especially lemon and pomelo, their chemical properties, composition, and their use in health and cosmetic needs.

… -flow mode with a distribution head that permits maximum filling of … Glucosides of limonin and other limonoids found in citrus … , the pulp content is too high and the juice and excess pulp …

Citrus fruits are among the most widely cultivated and consumed crops worldwide, exhibiting a complex evolutionary history driven by extensive hybridization and genomic admixture. They are widely appreciated for their sensory quality, rich nutritional composition, and health-promoting benefits, as well as for their significant contribution to the global economy. Considering the growing interest in citrus crops and particularly in citrus by-products as valuable natural resources, as evidenced in the comprehensive literature search, this study provides an overview of recent advances in our understanding of citrus origin, genetic diversity and global production trends. It also examines the phytochemical composition of citrus fruits and by-products and discusses the biological activities associated with these constituents, including antioxidant, antimicrobial and anti-inflammatory effects, as well as their potential health benefits. Additionally, conventional and environmentally friendly strategies for the utilization of citrus residues are presented within a biorefinery framework, with particular emphasis on the recovery and valorization of bioactive compounds. These circular economy approaches highlight the potential use of citrus by-products as valuable raw materials for applications in food, cosmetic and pharmaceutical fields. Overall, this review aims to provide a better understanding of citrus history, composition and potential applications that could support the sustainable and resource-efficient use of citrus substrates in industrial practice for the development of high-value products.

… The citrus pulp contains compounds with antibiotic-like properties that can reduce the … The citrus pulp contains high levels of phenolic compounds, flavonoids, and limonoids, which …

… cultivar that showed the highest content of limonin, while “Salustiana” showed the lowest (Figure 3). Limonin is a bitter compound present in citrus … measuring the limonin content is also …

… of Washington Navel, Kozan Yerli, sour orange and total phenolic content of all citrus varieties. … Also, in this study, limonin contents of control samples increased with time in all varieties. …

… limonin content in juice varied between the different cultivars, neither acid nor brix correlated with limonin content … The limonin content of the juice showed an overall decrease during the …