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Concept: Tangelo


Two cultivars (Citrus grandis (L.) Osbeck PO 51 and PO 52) of Malaysian pomelo juices were studied by examining their physicochemical properties (i.e. pH, °Brix and titratable acidity), volatile and non-volatile components (sugars and organic acids). Using solvent extraction and headspace solid-phase microextraction, 49 and 65 volatile compounds were identified by gas chromatography-mass spectrometer/flame ionisation detector, respectively. Compared to pink pomelo juice (cultivar PO 52), white pomelo juice (cultivar PO 51) contained lower amount of total volatiles but higher terpenoids. Descriptive sensory evaluation indicated that white pomelo juice was milder in taste especially acidity. Furthermore, principal component analysis and partial least square regression revealed a strong correlation in pomelo juices between their chemical components and some flavour attributes (i.e. acidic, fresh, peely and sweet). Hence, this research enabled a deeper insight into the flavour of this unique citrus fruit.

Concepts: Acid, Citrus, PH, Orange, Grapefruit, Pomelo, Tangelo, Juice vesicles


The effects of various factors, including the extraction time, temperature, solvent/material ratio, the ultrasonic intensity and duty cycle of ultrasonic irradiation on the extraction yield of all-trans-lycopene from red grapefruit by ultrasound-assisted extraction (UAE) were investigated. In comparison with conventional solvent extraction (CSE), UAE showed a pronounced greater extraction yield and reduced extraction time effectively with a peak value at 30 min. The extraction yield was significantly influenced by temperature and the optimum condition was 30 °C. The extraction yield increased with increasing of solvent/material ratio until equilibrium was arrived at the optimal ratio of 3:1 (mL/g). The extraction yield increased first and then decreased with an increase in ultrasonic intensity. The extraction yield of UAE increased with the increase of duty cycle, whereas pulsed ultrasound with proper intervals was more efficient than continuous ultrasonication. The degradation via isomerisation of all-trans-lycopene under ultrasonic treatment was also observed with the formation of 9,13'-di-cis-, 9,13-di-cis-, 15-cis-, 13-cis- and 9-cis-lycopene isomers which were tentatively identified by HPLC-PAD.

Concepts: Citrus, Physical quantities, Grapefruit, Tangelo


Aroma extract dilution analyses of the aromas of peels and juices of white and pink grapefruits revealed that rotundone that was responsible for woody odor was detected at higher flavor dilution factors of 256 to 1024. In both juices, rotundone was detected at the highest FD factor of 1024. Rotundone in the grapefruits was quantitated by a stable isotope dilution assay with a newly synthesized deuterium-labeled internal standard, rotundone-d2,3: its levels were 2180 and 1920 ng/kg in white and pink grapefruit peels, and 29.6 and 49.8 ng/kg in white and pink grapefruit juices. On the basis of these results, sensory analysis was performed to assess the effects of rotundone on a white grapefruit juice aroma reconstitute. This sensory analysis revealed that rotundone does not only impart a woody note or affect one of the existing attributes, but also increases various attributes, and thus confirmed that rotundone is indispensable for the aroma of grapefruit juice.

Concepts: Citrus, Grapefruit, Grapefruit juice, Tangelo, Grapefruit spoon


Although studies have quantified bacterial transfer between hands and various materials, cross-contamination between the surface of fresh citrus fruit and the edible portions during hand peeling has not been reported. This study quantifies transfer of Salmonella to the edible portion of citrus fruit from a contaminated peel during hand peeling. Citrus fruits used for this study were Citrus sinensis (sweet orange) cultivars ‘Valencia’ and ‘Navel’, Citrus unshiu (Satsuma mandarins), Citrus reticulata × Citrus paradisi (‘Minneola’ tangelo or ‘Honeybell’), and C. paradisi (grapefruit) cultivar ‘Marsh’. An avirulent Salmonella Typhimurium LT2 (ATCC 700720) resistant to rifampin was used for all experiments. The inoculum containing approximately 9 log CFU/mL (50 μL) was spot inoculated onto the equator, stem, or styler of each fruit and allowed to dry for 24 h. Six volunteers put on single-use latex gloves and peeled inoculated fruit. Peel, edible fruit portion, and gloves were collected and enumerated separately. Three replicates of the study were performed in which each volunteer peeled two inoculated fruit of each variety (n = 36 fruit per variety). Cross-contamination from contaminated surface of citrus fruits to edible portion or gloved hands during peeling was affected by inoculation sites. Average Salmonella transfer to the edible portion ranged from 0.16% (Valencia inoculated at the equator) to 5.41% (navel inoculated at the stem). Average Salmonella transfer to gloved hands ranged from 0.41% (grapefruit inoculated at the stem) to 8.97% (navel inoculated at the stem). Most Salmonella remained on the peel of citrus fruits. The average level of Salmonella remaining on the peel ranged from 5.37% (Minneola inoculated at the equator) to 66.3% (Satsuma inoculated at the styler). When grapefruit was inoculated, the Salmonella that remained on the peel showed a bimodal pattern in which some individuals left almost all Salmonella on the peel, while others left substantially less.

Concepts: Citrus, Fruit, Orange, Grapefruit, Rutaceae, Pomelo, Tangelo, Mandarin orange


The aim of this systematic review was to evaluate the evidence for or against the effectiveness of grapefruits (Citrus paradisi) on body weight, blood pressure and lipid profile. Electronic searches were conducted in MEDLINE, EMBASE, AMED and the Cochrane Clinical Trials databases to identify relevant human randomized clinical trials (RCTs). Hand searches of bibliographies were also conducted. Only overweight and obese subjects were included. The reporting quality was assessed using the CONSORT checklist, and the strength of the overall body of evidence was rated based on the GRADE criteria. 154 citations were identified and three RCTs with a total of 250 participants were included. The RCTs were of moderate quality. A meta-analysis for change in body weight failed to reveal a significant difference between grapefruits and controls, MD: -0.45 kg (95% CI: -1.06 to 0.16; I(2) = 53%, but analysis revealed a significant decrease in systolic blood pressure, MD: -2.43 mmHg (95%CI: -4.77 to -0.09; I(2) = 0%). Paucity in the number of RCTs, short durations of interventions, and lack of an established minimum effective dose limit the conclusions that can be drawn about the effects of grapefruit on body weight and metabolic parameters. Further clinical trials evaluating the effects of grapefruit are warranted.

Concepts: Epidemiology, Clinical trial, Evidence-based medicine, Effectiveness, Citrus, Grapefruit, Tangelo


The consumption of citrus fruits is associated with health benefits. However, clinical data regarding the effects of grapefruit flavanone consumption on vascular function are lacking.

Concepts: Clinical trial, Crossover study, Citrus, Fruit, Orange, Grapefruit, Tangelo, Naringin


Pomelo (Citrus grandis) is the largest citrus fruits, whose peel is one of the well-known agricultural wastes. Amounts of pomelo peel is disposed after consumption, causing serious environment problem. As a natural, versatile bio-absorbent, pomelo peel showed excellent adsorption capacity attributing to its micro-pores to several pollutants, however, there is no relevant report on its adsorption capacity in natural products or food ingredients. The ability of pomelo peel for adsorbing Epigallocatechin-3-gallate (EGCG) was examined in this study. The physicochemical characterizations of pomelo peel were determined by Fourier transform infrared spectroscopy, scanning electron microscopy and HPLC analysis. The adsorption process of EGCG onto pomelo peel from aqueous solution was carried out with a range of concentrations (50 - 800 mg/L) and temperatures (25, 40 and 55 °C).

Concepts: Spectroscopy, Concentration, Citrus, Orange, Infrared spectroscopy, Fourier transform spectroscopy, Grapefruit, Tangelo


Grapefruit (Citrus paradisi Mcfad) is a perenifolium tree 5-6 m high with a fruit of about 15 cm in diameter, protected by the peel we can find about 11-14 segments (carpels), each of which is surrounded by a membrane and each containing the juice sacs, as well as the seeds. The fruit is made up of numerous compounds, and is known to have nutritive value because of the presence of various vitamins and minerals, among other chemicals. The fruit is also used in the field of gastronomy. Information has been accumulated regarding the participation of the fruit structures in a variety of biomedical, antigenotoxic and chemopreventive effects, surely related with the presence of the numerous chemicals that have been determined to constitute the fruit. Such studies have been carried out in different in vitro and in vivo experimental models, and in a few human assays. The information published so far has shown interesting results, therefore, the aims of the present review are to initially examine the main characteristics of the fruit, followed by systematization of the acquired knowledge concerning the biomedical, antigenotoxic and chemopreventive effects produced by the three main structures of the fruit: peel, seed, and pulp.

Concepts: In vivo, Citrus, In vitro, Fruit, Orange, Seed, Grapefruit, Tangelo


Hot water treatment (HWT) against Anastrepha ludens were developed achieving 48°C in the core of grapefruits and holding it for 6 min. After heating, the grapefruits were hydro-cooled and stored at 23°C and analyzed for 16 days. The effect of microwave-assisted hot water treatment (MW-HWT) on grapefruit quality was analyzed and compared with the quality of fruits treated with HWT and control fruits (without treatment). The physico-chemical properties and chemical composition of essential oil were analyzed.

Concepts: Citrus, Fruit, Orange, Grapefruit, Tangelo


The mandarin horticultural group is an important component of world citrus production for the fresh fruit market. This group formerly classified as C. reticulata is highly polymorphic and recent molecular studies have suggested that numerous cultivated mandarins were introgressed by C. maxima (the pummelos). C. maxima and C. reticulata are also the ancestors of sweet and sour oranges, grapefruit, and therefore of all the “small citrus” modern varieties (mandarins, tangors, tangelos) derived from sexual hybridization between these horticultural groups. Recently, NGS technologies have greatly modified how plant evolution and genomic structure are analyzed, moving from phylogenetics to phylogenomics. The objective of this work was to develop a workflow for phylogenomic inference from Genotyping By Sequencing (GBS) data and to analyze the interspecific admixture along the nine citrus chromosomes for horticultural groups and recent varieties resulting from the combination of the C. reticulata and C. maxima gene pools. A GBS library was established from 55 citrus varieties, using the ApekI restriction enzyme and selective PCR to improve the read depth. Diagnostic polymorphisms (DPs) of C. reticulata/C. maxima differentiation were identified and used to decipher the phylogenomic structure of the 55 varieties. The GBS approach was powerful and revealed 30,289 SNPs and 8,794 Indels with 12.6% of missing data. 11,133 DPs were selected covering the nine chromosomes with a higher density in genic regions. GBS combined with the detection of DPs was powerful for deciphering the “phylogenomic karyotypes” of cultivars derived from admixture of the two ancestral species after a limited number of interspecific recombinations. All the mandarins, mandarin hybrids, tangelos and tangors analyzed displayed introgression of C. maxima in different parts of the genome. C. reticulata/C. maxima admixture should be a major component of the high phenotypic variability of this germplasm opening up the way for association studies based on phylogenomics.

Concepts: Gene, Molecular biology, Citrus, Orange, Grapefruit, Rutaceae, Pomelo, Tangelo