Citrus Seeds Research Articles

Production and characterization of liquid biofuels from locally available nonedible feedstocks

AbstractMandarin (Citrus reticulata) seeds were exploited as possible nonedible feedstock for the synthesis of liquid biofuels, namely, biodiesel and bio‐oil via alkali–alcoholysis and pyrolysis routes, respectively. The alkali–alcoholysis reaction of mandarin seed oil with an equivalent mixture of methanol–ethanol alcohols was examined and optimized by analysis of variance (ANOVA). The best experimental yield of biodiesel (95.55 ± 1.55 wt.%) was comparable with the predicted yield (95.0 wt.%). Also, analysis by one‐way ANOVA showed that the selected variables were statistically significant. The 1H NMR spectroscopy asserted the transformation of the oil to biodiesel. Also, the evaluated properties of the biodiesel were in the range given by ASTM D6751 standards. The mandarin citrus seeds have also subjected to the thermal pyrolysis process in a fixed‐bed reactor to obtain bio‐oil and bio‐char. The influence of the pyrolysis temperature, time, feed particle size, and heating rate on the bio‐oil yield was optimized. The highest yield of bio‐oil (52.34 ± 1.25 wt.%) was attained at 475°C for 60 min using 70 mesh particle size of the feed with a heating rate of 20°C/min. The bio‐oil was analyzed by Fourier transform infrared spectroscopy (FTIR), 1H NMR spectroscopy, and ultimate analysis. The bio‐oil derived from MCS has an empirical formula of CH1.88 O0.16 N0.012 S0.0005 with 37.96 MJ/kg of heating value. The elevated carbon level, low oxygen content, and high calorific value (25.45 MJ/kg) of the attained bio‐char suggest its suitability as a solid fuel. Also, the obtained bio‐char can be utilized for preparing carbon adsorbent as a result of its good surface area.

Food factors that mimic bile acid functions

TGR5 is a member of the G protein-coupled receptor family and is activated by bile acids. TGR5 is thought to be a promising food factor target for preventing metabolic diseases because the activation of TGR5 prevents obesity and hyperglycemia in mice fed a high-fat diet. In the present study, we established an evaluation system for the TGR5 ligand activity, and identified a limonoid nomilin as an activator of TGR5 from among approximate 150 purified food compounds. Unlike bile acids, nomilin did not exhibit the farnesoid X receptor ligand activity. Although the nomilin derivative obacunone was capable of activating TGR5, limonin (the most abundant limonoid in citrus seeds) was not a TGR5 activator. When male C57BL/6J mice fed a high-fat diet for 9 weeks were further fed a high-fat diet either alone or supplemented with 0.2% w/w nomilin for 77 days, nomilin-treated mice had lower body weight, serum glucose, serum insulin, and enhanced glucose tolerance. Our results suggest a novel biological function of nomilin as an agent having anti-obesity and anti-hyperglycemic effects that are likely to be mediated through the activation of TGR5.

Revisiting seed transmission of ‘Candidatus Liberibacter asiaticus’ in different citrus species and hybrids

Huanglongbing (HLB) caused by ‘Candidatus Liberibacter spp.’ is the most destructive disease for citrus production. These bacteria are disseminated naturally by insect vectors, such as the psyllid Diaphorina citri. However, the transmission of the bacteria vertically from seeds to seedlings has been controversial. Therefore, the objective of this study was to re-investigate the vertical transmission of the bacterium ‘Ca. Liberibacter asiaticus’ (CLas) from seeds to seedlings. Seeds of ‘Rangpur’ lime, ‘Swingle’ citrumelo, ‘Ponkan’ mandarin and the sweet oranges ‘Folha Murcha’, ‘IAPAR-73’, ‘Pera Rio’, ‘Shamouti’ and ‘Valencia’ were included in the study. Besides the seeds, 3493 citrus seedlings were also examined for the presence of the bacterium and for the development of HLB symptoms. The presence of the bacterium in different parts of the seeds and in citrus seedlings was examined by standard PCR. CLas was detected in all parts of the seeds, including seed coat or testa, tegmen, and endosperm plus embryos of all citrus cultivars, except for ‘Shamouti’ sweet orange. Although transient, the presence of the HLB bacterium was also detected in seedlings of ‘Ponkan’ mandarin and ‘Folha Murcha’ sweet orange obtained from seeds of HLB-infected trees up to 18 months after seedlings transplanting. However, no typical symptoms of HLB were observed in the citrus seedlings. Although CLas may infect the citrus seeds, the results of this study do not support the vertical transmission of viable cells of CLas from seeds to seedlings.

UJI VIABILITAS TERHADAP BENIH POLYEMBRIONI

Seeds are mature ovules. One or more of the ovaries formed in the legume, but never more than one seed formed in the ovaries of monocots. Each ripe seed always consists of at least two parts, namely: (1) Embryo, (2) Seed coat (Seed coat or testa). Embryo is formed or derived from fertilized eggs (zygote) by undergoing cell division in the embryo sac. Seed coat is formed from the integument (one or more) of the ovules. In legumes generally there are two layers of seed coat. Every very young and growing seed always consists of three parts: (1) Embryo, (2) seed coat, (3) Endosperm. Endosperm is a storage food storage network which is absorbed by the embryo before or during seed germination and is always present in very young seeds. Polyembryonics is the presence of more than one embryo in one seed, but these embryos do not always mature or mature, remain undeveloped or degenerate. The purpose of this research is to study the germination of one seed that has more than one embryo and to determine the growth of seedlings from polyembryonic seeds. The results showed that the highest plant growth (plant height, number of leaves, fresh weight and dry weight of orange seeds) was found in orange seeds that had 1 embryo compared to orange seeds which had 2 and 3 embryos. Seed germination and growth is strongly influenced by the amount of food reserves stored in seeds (Magagula and Ossom 2011 in Hasnah M, 2013). Keywords: Citrus Seed, Polyembrioni, Seed Viability

Influence of Sumac Extract on the Physico-chemical Properties and Oxidative Stability of Some Cold Pressed Citrus Seed Oils.

The acidity values changed between 1.03 mgKOH/100g (control) and 1.11 mgKOH/100g (0.1% extract) for orange oil, 1.06 mgKOH/100g (0.5% extract) and 1.13 mgKOH/100g (0.1% extract) and 1.25 mgKOH/100g (0.5% extract) and 1.31 mgKOH/100g (control) for mandarin oil. The peroxide values were determined between1.37 meqO2/kg (0.5% extract) and 1.43 meqO2/kg (0.1% extract) for orange oil, between 1.24 meqO2/kg (control) and 1.27 meqO2/kg (0.1% extract) for lemon and 1.60 meqO2/kg (0.5% extract) and 1.71 meqO2/kg (control) in mandarin oil samples. The viscosity values of samples changed between 0.051 Pa.S (control) and 0.065 Pa.S (0.5% extract) for orange, 0.051 Pa.S (control) and 0.067 Pa.S (0.5% extract) lemon and 0.044 Pa.S (control) and 0.057 Pa.S (0.5% extract) in mandarin oil samples. At the end of storage study (28th day), the acidity values significantly changed, and their values ranged between 2.28 mgKOH/100g (0.5% extract) and 3.64 mgKOH/100g (control) in orange, 1.67 mgKOH/100g (0.5% extract) and 2.28 mgKOH/100g (control) in lemon and 1.74 mgKOH/100g (0.5% extract) and 2.36 mgKOH/100g (control) in mandarin oil samples. While peroxide values vary between 11.68 meqO2/kg (0.5% extract) and 32.57 meqO2/kg (control) for orange, 12.55 meqO2/kg (0.5% extract) and 34.63 meqO2/kg (control) for lemon and between 17.56 meqO2/kg (0.5% extract) and 37.81 meqO2/kg (control) for mandarin oils, viscosity values after 28 day storage changed between 0.123 Pa.S (0.5% extract) and 0.675 Pa.S (control) in orange, 0.257 Pa.S (0.5% extract) and 0.697 Pa.S (control) in lemon and 0.215 Pa.S (0.5% extract) and 0.728 Pa.S (control) in mandarin oil samples.

Physiological quality of citrandarins, Poncirus trifoliata and Sunki mandarin seeds

Rangpur lime is the rootstock most used in Brazil, mainly due to its resistance to drought; however, it is susceptible to several diseases, requiring the search for other rootstocks tolerant to factors limiting citrus cultivation. In addition, the Brazilian legislation stipulates that citrus seeds can only be commercialized with at least 50% germination rate. Thus, the aim of this work was to evaluate the physiological quality of seeds of seven citrus rootstocks. The following citrus fruits were harvested: Poncirus trifoliata, Sunki mandarin and their hybrids –citrandarins (70, 106, 254, 299 and 310). Fruit mass, diameter and height were measured. Seeds were extracted from fruits, counting the number of normal seeds (not aborted). Seeds were dried up to 20% water content and stored for 3, 6, 9 and 12 months. The physiological quality of seeds was evaluated before storage (time 0) up to 12 months of storage. The quality of Poncirus trifoliata, Sunki mandarin and citrandarins 70, 106, 254, 299 and 310 seeds was reduced during storage. However, their germination rate remained above 50%, evidencing that seeds of all rootstocks could be marketed until 12 months of storage. The new rootstocks tested have seeds with physiological quality compatible with their parents, in compliance with current legislation.

Maturation and physiological quality of IAC-863 Rangpur lime seeds

There is a growing demand for high quality seeds to obtain citrus rootstocks. Normative Instruction 48 (MAPA) of September 24, 2013, requires minimum of 50% germination for the marketing of citrus seeds. Harvest season is one of the stages of seed production with great importance to ensure quality, which makes knowing its maturation process an important step. Thus, the objective of this study was to monitor physicochemical changes in IAC-863 Rangpur lime fruits in order to characterize the physiological maturity of seeds, and to define the ideal harvest point in order to obtain seeds with high physiological quality to obtain rootstocks. Physicochemical analysis of fruits (mass loss, color, soluble solids and acidity) and analysis of seeds (water content, germination and emergence) was performed. Higher germination results were observed in seeds obtained from fruits with higher color index and soluble solids content. The storage of IAC-863 Rangpur lime fruits after harvest increases germination rate, especially in mid-season fruits.

Identification and quantification of limonoid aglycones content of Citrus seeds

Citrus fruits are recognized as an important source of bioactive molecules such as limonin and nomilin. However, these molecules exhibit low bioavailability, therefore, obtaining these molecules using biotechnological techniques may be an alternative to harvesting them directly from fruits. The aim of this study was to quantify and identify limonoids in the dichloromethane extracts of Citrus seeds of Criolla orange, Oneco tangerine, Tangerine-lemon, Sour orange and Valencia orange from department of Antioquia-Colombia by high performance liquid chromatography with diode array detection, and high-resolution mass spectrometry. Although in all the samples total glycosidic free limonoids were present, Oneco tangerine seeds had the highest concentration, followed by Tangerine-lemon seeds, equivalent to 0.75% and 0.53% per total dry weight, respectively. These results suggest Oneco tangerine seeds may be used as an elite material for biotechnological processes looking for increased production of limonoids to support research and drug development.

In vitro study the effect of salinity stress on two citrus rootstock growth (Citrus Aruntium), (Cleopatra Mandarin)

This study was conducted at the plant tissue plant of the Biotechnology Research Center for the purpose of determining the effect ofadding different concentrations of Nacl on the growth and development of the citrus rootstocks (Narang and Cleopramtradrin). Citrus seeds were cultured on MS media supplemented with different concentrations ofNaCL100,80,60,40,20,0 mM. The result showed that citrus rootstocks growth negatively infected by salinity while plant length and number of laves decreased by increasing of salinityfor booth rootstocks .plant length and number of leaves were significantly higher in treatment 0 and 20 mMNaCL compared with other treatments, also the results showed that the plants continued to grow well until 60 mM concentration..

Reunion overseas: introduced wild boars and cultivated orange trees interact in the Brazilian Atlantic Forest

Abstract: Reunion in the overseas: introduced wild boars and cultivated orange trees interact in the Mata Atlântica (Brazil). Novel interactions are attracting a lot of interest, especially those occurring between wild animal species and agricultural crops as a consequence of human activities. Novel interactions usually concern to species that interact only because human activity but that otherwise would not even coexist. Typically novel interactions arise from biological invasions as well as from interactions between native and crop species. Less studied are novel interactions between species that originally interact in their native range but, as consequence of human activity (domestication, game introductions, etc.), are now interacting out of their original distribution under new ecological conditionsIn this article, we study the interaction between orange and wild boar, both species sharing Asian origin but being introduced in America and then subjected to new ecological conditions. Dispersers of sweet orange seeds are unknown. As wild boar consumes fruits frequently in citrus orchards, here we assessed whether i) it consumes orange seeds, ii) they are viable after passing through boar’s digestive tract and iii) orange seedlings may naturalise in the Mata Atlântica of Brazil, in a citrus farm surrounded by a large natural area called Mata da Virgínia. We used camera surveys in the orange orchards and in the jungle to identify orange fruit consumers in two periods in 2014 and 2015. The jungle was additionally surveyed looking for citrus seedlings finding more than 50 seedlings in which it was confirmed that they belong to sweet orange trees by SSR techniques. As the wild boar was identified as the main orange consumer, 19 fresh boar feces were collected and citrus seeds removed and sown to assess their viability. Citrus seeds were also planted in the jungle and their germination and seedling survival were studied. Three years after sowing, just 5% of the seedlings remained alive with an average height of less than 10 cm.

Supercritical CO2 Extraction of Waste Citrus Seeds: Chemical Composition, Nutritional and Biological Properties of Edible Fixed Oils

Seeds of Citrus plants (Rutaceae), an major agro‐industrial waste, are a potential source of valuable by‐products. The chemical composition, the antioxidant profile, and the biological/nutritional properties of fixed oils (SFE oils) obtained by supercritical CO2 extraction (at 300 bar and 40 °C) from seeds of mandarin (Citrus reticulata), lemon (Citrus limon), and grapefruit (Citrus paradisi), discarded by a local agro‐alimentary industry are studied. The yields and compositions of SFE oils are compared to oils obtained by n‐hexane extraction of Citrus seeds in a Soxhlet apparatus (SoxE oils). Linoleic (35–42%), oleic (22–28%), palmitic (21–25%), α‐linolenic (4–10%), and stearic (4–7%) are the main oil fatty acids, while monolinolein and dilinolein derivatives represent the main triacylglycerols in SFE oils, determined by GC‐FID and HPLC‐DAD/ELSD techniques. Citrus SFE oils show lower yields than SoxE oils but similar chemical profiles. Principal components analysis applied to fatty acid and triacylglycerol data indicates that the oils from different seeds are tightly clustered. Moreover, SFE oils show radical scavenging activities (ABTS assays), an inhibitory effect on the growth of murine B16F10 melanoma cells and on the mushroom tyrosinase activity. Citrus SFE oils and de‐coated seeds are also evaluated for their attractant effect on the Mediterranean fruit fly Ceratitis capitata by behavioral assays. The results qualify Citrus SFE oils as a potential natural, environmentally‐friendly, resource for food/pharmaceutical applications.Practical Applications: The environmentally‐friendly supercritical CO2 extraction of waste lemon, mandarin, and grapefruit seeds gives edible fixed oils a richness in essential fatty acids, suitable for human nutrition and the preparation of nutraceuticals and pharmaceuticals.Edible fixed oils obtained from lemon, mandarin, and grapefruit seeds by SFE‐CO2 extraction show high levels of essential fatty acids, antioxidant, anticancer, and antityrosinase activity.

Optimization of cryopreservation protocols for zygotic embryos of Citrus reticulata

Citrus seeds are known to have short life spans in conventional seed banks. Seed of most Citrus species show a typical intermediate storage behaviour where they survive desiccation to c. 7-10%. However, longevity is compromised at this low moisture content at sub-zero temperatures. Cryopreservation of zygotic embryos is an option for the long-term storage of germplasm of this species and we investigated its feasibility for Citrus reticulata var. Mandarin. The experimental strategies evaluated included: seed and embryo desiccation sensitivity assessment, naked embryo cryopreservation, encapsulation-dehydration cryopreservation, and cryopreservation of embryos following the PVS2 vitrification technique. Differential scanning calorimetry was used at every desiccation step to determine the critical water content for cryopreservation. Desiccated and cryopreserved naked embryos with a moisture content of 13% (fresh weight basis) showed the highest regrowth (60%). Maximum regrowth of about 58 and 52% was recorded for encapsulated embryos with a moisture content of ~22% and for embryos treated with PVS2 vitrification for 120 min, respectively. Although encapsulated, PVS2 treated and naked embryo cryopreservation had almost similar regrowth percentages, the seedlings obtained from naked embryo cryopreservation appeared more vigorous, probably because of the lack of mechanical contraints imposed by the alginate encapsulation and no exposure to cryo-protectant, a known plant stressor. We conclude that naked embryo desiccation is the optimum technique for cryopreservation of C. reticulata zygotic embryos.

Laboratory Evaluation of Extract from Peels and Seeds of Some <i>Citrus</i> Species against <i>Anopheles</i> Mosquitoes (Diptera: Culicidae)

Mosquitoes are the most important group of insects known for their public health importance. Efforts to eradicate this disease involve elimination of the vector with natural base insecticides which are safer when compared to synthetic insecticides which are harmful to human. Toxicity effect of extracts from peels and seeds of Citrus sinesis , Citrus aurantifolia and Citrus limonum were evaluated against adult Anopheles mosquitoes at different concentrations and time of exposure; 20, 40 and 60 minutes. The peels and seeds were air dried for 15 days before pulverization. The pulverized peels and seeds were subjected to extraction using soxhlet apparatus and ethanol as solvent. The stock solutions were prepared by adding 0.1 mL of extract to 9.9 mL of ethanol to make 1% concentration. The following different concentrations 5, 10, 15, 20, and 25% of the extract were prepared as followed; 0.5, 1.0, 1.5, 2.0 and 2.5 mL of the extract were dissolved in 9.5, 9.0, 8.5, 8.0 and 7.5 mL of the solvent (Ethanol) respectively with three (3) replicates for each concentration, while 10 mL of ethanol was used as the control (0%). The qualitative and quantitative analyses of the phytochemical constituents were analyzed. The efficacy of the extracted oils was tested on adult female Anopheles mosquitoes. At 25% concentration, C. aurantifolia peel extract recorded 62.22% mortality at 60 minutes while the seed extract recorded 50% mortality at the same concentration and time. The toxicity increased in respect to time of exposure, the toxicity estimation of LC 50 was 22.05% from the extract of C. aurantifolia peels and LC 95 was 112.27% for C. limonum peels extract after 60 minutes of application. The potency of the Citrus peels and seeds extracts may be as a result of the phytochemical constituents present in them. These results suggest that the Citrus peel and seed extracts have the potential to be used as ideally in eco-friendly approach for the control of the vector control programs.

EVALUATION OF BOTANICALS AND FUNGICIDES AGAINST SEED BORNE FUNGI AND GERMINATION OF ROUGH LEMON SEEDS

Citrus fruits are grown all over the world, including Pakistan. However, the poor storage conditions for citrus seeds in tropical and sub-tropical regions compromise their viability during growth. In this study, M. olifera (Moringa) and A. niger (Neem) leaves were used as seed coating agents and were utilized for the first time without any deep treatment of such leaves with an objective to reduce the cost of botanical fungicides and to control the harmful effects of synthetic fungicides. Topsin-M, a synthetic fungicide, was used as a reference compound to compare the results of fungicides from botanical sources than that of a traditionally available synthetic fungicide. Three different concentration of fungicide solutions (C1, C2 and C3), that were coated on the surface of seeds for different duration of time (8, 10 and 12h), were prepared. It was observed that the coating of seeds with fungicides, either botanical or synthetic, significantly improved the horticultural (germination %age and number of days required for germination) and pathological (fungi %age and number of contaminated seeds) parameters of rough lemon, as compare to control or non-coated seed samples. It is expected that the findings of this study will promote the use of botanicals as seed coating agent as they are readily available to famers and are also acceptable for the cultivation of organic crops.

Biotransformation and Metabolic Profile of Limonin in Rat Liver Microsomes, Bile, and Urine by High-Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry.

Limonin is a triterpenoid in citrus seeds, which has significant biological activities. However, the metabolic profile of limonin has not been fully understood. To expound its metabolism in vivo and in vitro, the metabolites of limonin was studied by rat liver microsomes, urine, and bile. High-performance liquid chromatography/quadrupole time-of-flight mass spectrometry was used for identification. Among the metabolites, the structures of M1 and M3 were confirmed by chemical synthesis and nuclear magnetic resonance spectra analysis. Our results indicated that reduction and hydrolysis were the two major pathways during limonin metabolism in vivo and in vitro. The results from this work are valuable and important for understanding the metabolic process of limonin.

Extraction, identification, and antioxidant property evaluation of limonin from pummelo seeds

Limonin, the main bioactive phytochemical constituent of limonoids with multi-functions, is enriched in citrus fruits and often found at a high concentration in citrus seeds. The present study was attempted to introduce a new and efficient extraction method to isolate limonoids from pummelo seeds, and to evaluate the antioxidant property of the main constituent limonin in HepG2 cells. Three key single factors were identified for the extraction of limonoids from pummelo seeds using the Box-Behnken experiment design of response surface methodology (RSM), and the optimized extraction parameters were treatment with 89.68 mL of anhydrous acetone for 4.62 h at 78.94 °C, while the yield of limonoids was 11.52 mg/g. The structure of isolated main constituent of the limonoids was further identified as limonin by Fourier transform infrared (FT-IR) spectrometer and nuclear magnetic resonance (NMR) spectrum. Moreover, the molecular data in HepG2 cells revealed that limonin exerted its anti-oxidant property mainly by the activation of nuclear factor (erythroid-2)-like 2 (Nrf2)/kelch-like ECH-associated protein 1 (Keap1)- antioxidant response element (ARE) pathway in the form of transcriptional regulation of Nrf2 mRNA and posttranscriptional regulation of Nrf2/Keap1 system. These results demonstrate that pummelo seeds are an ideal source of limonoids, and limonin is proved to exert its anti-oxidant property by the activation of Nrf2/Keap1 pathway.

Estimation of Polyploidy of Embryos and Gametes Based on Polyploidy of Endosperm Remaining in the Citrus Seed

Estimation of Polyploidy of Embryos and Gametes Based on Polyploidy of Endosperm Remaining in the Citrus Seed

Effect of location and Citrus species on total phenolic, antioxidant, and radical scavenging activities of some Citrus seed and oils

The objective of this study was to determine the total phenolic content, antioxidant activity, and radical scavenging effect of the seeds and seed oils of some Citrus fruits (mandarin, orange, and lemon) collected from different locations of Turkey on November in 2008 and 2009. The total phenolic content, antioxidant activity, and radical scavenging of citrus are 209.90–287.20 mg gallic acid equivalent (GAE)/kg, 1.24–2.04 mmol TE/kg, and 2.21–0.73 DPPH. IC50 of mandarin;198.40–230.40 mg GAE/kg, 1.49–1.83 mmol TE/kg, and 1.40–0.58 DPPH. IC50 of orange; 152.70–212.30 mg GAE/kg, 1.39–1.86 mmol TE/kg, and 2.35–0.66 DPPH. IC50 of lemon seeds, respectively. They are 71.12–87.00 mg GAE/kg, 0.39–1.21 mmol TE/kg, and 5.93–3.74 DPPH. IC50 of mandarin; 46.63–92.80 mg GAE/kg, 0.65–1.18 mmol TE/kg, and 8.02–2.05 DPPH. IC50 of orange; 63.41–92.51 mg GAE/kg, 0.50–1.56 mmol TE/kg, and 3.24–2.83 DPPH. IC50 of lemon seed oils, respectively. The parameter levels are found lower in Citrus seed oils then seeds. Practical Application Citrus fruits are especially rich sources of important phenolic compounds. Antioxidants are the substances that delay the beginning of the oxidation. Phenolic compounds are widely distributed in fruits and vegetables and secondary metabolites which are synthesized in plants. Citrus seeds are a potential source for nutrients. Citrus seeds are important sources of oils.

The effect of drying temperatures on antioxidant activity, phenolic compounds, fatty acid composition and tocopherol contents in citrus seed and oils.

In this study, the effect of drying temperature on antioxidant activity, phenolic compounds, fatty acid composition and tocopherol content of citrus seeds and oils were studied. Kinnow mandarin seed, dried at 60°C, exhibited the highest antioxidant activity. Orlendo orange seed had the maximum total phenolic content and α-tocopherol content, with a value of 63.349mg/100g and 28.085mg/g (control samples), respectively. The antioxidant activity of Orlendo orange seed (63.349%) was higher than seeds of Eureka lemon (55.819%) and Kinnow mandarin (28.015%), while the highest total phenolic content was found in seeds of Kinnow mandarin, followed by Orlendo orange and Eureka lemon (113.132). 1.2-Dihydroxybenzene (13.171), kaempferol (10.780), (+)-catechin (9.341) and isorhamnetin (7.592) in mg/100g were the major phenolic compounds found in Kinnow mandarin. Among the unsaturated fatty acids, linoleic acid was the most abundant acid in all oils, which varied from 44.4% (dried at 80°C) to 46.1% (dried at 70°C), from 39.0% (dried at 60°C) to 40.0% (dried at 70°C). The total phenolic content, antioxidant activity and phenolic compounds of citrus seeds and tocopherol content of seed oils were significantly affected by drying process and varied depending on the drying temperature.

Swingle citrumelo seed vigor and storability associated with fruit maturity classes based on RGB parameters

Citrus seeds normally have low storability. Identifying an optimal fruit harvest time for production of high vigor seeds is important for nurseries; however, identifying this stage for Swingle citrumelo fruits has been based only on visual color examination, and research related to this parameter has been inconsistent. The main objective of this study was to evaluate a red-green-blue (RGB) color measurement system for successful identification of Swingle citrumelo fruits possessing seeds with maximum physiological potential and storability. Fruits were harvested at three ripening stages identified as green (G), greenish-yellow (GY), and yellow (Y) pericarp, photographed, and the images processed using ImageJ software. Data were expressed as the average pixel value of R, G and B color components and a mean RGB pixel value (R+G+B/3). After harvest, seeds were evaluated for water content, germination, seedling emergence, length, dry mass and vigor as measured by the Seed Vigor Imaging System - SVIS (uniformity and vigor indexes) after 0 and 5 months storage (5 °C and 65 % relative humidity). Percentage of ruptured coat seeds was also evaluated after extraction. The R color component provided the best identification of each G, GY and Y fruits. Seeds extracted from GY fruits had higher storage potential compared with seeds from G and Y fruits. Thus, precise fruit ripening classification can be generated using the RGB color system to identify the best time for harvest to obtain seeds with greater physiological and storage potential.