Orange Peel Essential Oil Research Articles

Limonene anti-TMV activity and its mode of action

The main component of orange peel essential oil is limonene. Limonene is a natural active monoterpene with multiple functions, such as antibacterial, antiseptic and antitumor activity, and has important development value in agriculture. This study found that limonene exhibited excellent anti-tobacco mosaic virus (TMV) bioactivity, with results showing that its protection activity, inactivation activity, and curative activity at 800 μg/mL were 84.93%, 59.28%, and 58.89%, respectively—significantly higher than those of chito-oligosaccharides. A direct effect of limonene on TMV particles was not observed, but limonene triggered the hypersensitive response (HR) in tobacco. Further determination of the induction activity of limonene against TMV demonstrated that it displayed good induction activity at 800 μg/mL, with a value of 60.59%. The results of physiological and biochemical experiments showed that at different treatment days, 800 μg/mL limonene induced the enhancement of defense enzymes activity in tobacco, including of SOD, CAT, POD, and PAL, which respectively increased by 3.2, 4.67, 4.12, and 2.33 times compared with the control (POD and SOD activities reached highest on the seventh day, and PAL and CAT activities reached highest on the fifth day). Limonene also enhanced the relative expression levels of pathogenesis related (PR) genes, including NPR1, PR1, and PR5, which were upregulated 3.84-fold, 1.86-fold and 1.71-fold, respectively. Limonene induced the accumulation of salicylic acid (SA), and increased the relative expression levels of genes related to SA biosynthesis (PAL) and reactive oxygen species (ROS) burst (RBOHB), which respectively increased by 2.76 times and 4.23 times higher than the control. Systemic acquired resistance (SAR) is an important plant immune defense against pathogen infection. The observed accumulation of SA, the enhancement of defense enzymes activity and the high-level expression of defense-related genes suggested that limonene may induce resistance to TMV in tobacco by activating SAR mediated by the SA signaling pathway. Furthermore, the experimental results demonstrated that the expression level of the chlorophyll biosynthesis gene POR1 was increased 1.72-fold compared to the control in tobacco treated with 800 μg/mL limonene, indicating that limonene treatment may increase chlorophyll content in tobacco. The results of pot experiment showed that 800 μg/mL limonene induced plant resistance against Sclerotinia sclerotiorum (33.33%), Phytophthora capsici (54.55%), Botrytis cinerea (50.00%). The bioassay results indicated that limonene provided broad-spectrum and long-lasting resistance to pathogen infection. Therefore, limonene has good development and utilization value, and is expected to be developed into a new botanical-derived anti-virus agent and plant immunity activator in addition to insecticides and fungicides.

ANN and RSM Modeling for the Synthesis of Avocado Seed Starch Combined Orange Peel Extract Antimicrobial Packaging Film

Cooperation of essential oil into film formation results in active packaging materials, which can improve the quality and freshness of the foods and extend the shelf life. In the present study, extraction of starch and essential oil was performed. The active films were developed through the solvent casting method. The influence of avocado seed starch and orange peel essential oil was investigated and optimized using response surface methodology and an artificial neural network on the tensile strength, water vapor permeability, and antimicrobial properties of active films. The results showed that both models performed reasonably well, but trained artificial neural networks have more modeling capability rather than the response surface method. The optimum conditions were found to be orange peel oil of 0.57 g and 30% w/w of avocado seed starch with the values of the corresponding responses of 3.94 MPa, 3.098 × 10 − 10 g/ms Pa, and 17.273 mm for tensile strength, water vapor permeability, and inhibition zone, respectively. Generally, the orange peel extract had an effective and promising alternative for the commercial production of antimicrobial packaging films.

Characterization of Synthetic Polymer Coated with Biopolymer Layer with Natural Orange Peel Extract Aimed for Food Packaging.

This research was aimed to make biolayer coatings enriched with orange peel essential oil (OPEO) on synthetic laminate, oriented poly(ethylene-terephthalate)/polypropylene (PET-O/PP). Coating materials were taken from biobased and renewable waste sources, and the developed formulation was targeted for food packaging. The developed materials were characterized for their barrier (O2, CO2, and water vapour), optical (colour, opacity), surface (inventory of peaks by FTIR), and antimicrobial activity. Furthermore, the overall migration from a base layer (PET-O/PP) in an acetic acid (3% HAc) and ethanol aqueous solution (20% EtOH) were measured. The antimicrobial activity of chitosan (Chi)-coated films was assessed against Escherichia coli. Permeation of the uncoated samples (base layer, PET-O/PP) increased with the temperature increase (from 20 °C to 40 °C and 60 °C). Films with Chi-coatings were a better barrier to gases than the control (PET-O/PP) measured at 20 °C. The addition of 1% (w/v) OPEO to the Chi-coating layer showed a permeance decrease of 67% for CO2 and 48% for O2. The overall migrations from PET-O/PP in 3% HAc and 20% EtOH were 1.8 and 2.3 mg/dm2, respectively. Analysis of spectral bands did not indicate any surface structural changes after exposure to food simulants. Water vapour transmission rate values were increased for Chi-coated samples compared to the control. The total colour difference showed a slight colour change for all coated samples (ΔE > 2). No significant changes in light transmission at 600 nm for samples containing 1% and 2% OLEO were observed. The addition of 4% (w/v) OPEO was not enough to obtain a bacteriostatic effect, so future research is needed.

Process dynamics of orange peel essential oil extraction

ABSTRACT In this study, we investigated the extraction of essential oils from orange peels by steam distillation at the pilot plant level. We considered a two-stage mechanism to develop a kinetic model of oil extraction based on process dynamics principles with different dominant mechanisms. The first and second stages were found to be dominated by rapid diffusion and convection washing, and slow diffusion, respectively, with the diffusion speed in the first stage being considerably higher than that in the second. This model considered the inlet steam pressure and orange peel packing factor as independent variables based on their impact on the yield of the essential oils. High correlation coefficients were achieved through straightforward computation, demonstrating the goodness-of-fit of the model. Three important control parameters were determined for each stage, namely gain, time constant, and dead time; they provided an interesting insight into the mass transfer phenomena and served as a useful reference to minimize steam consumption. These control parameters support the design of an extraction process with a favorable impact on the production cost and environment.

EFFECT OF ORANGE PEEL ESSENTIAL OIL ON THE PROPERTIES OF CHITOSAN: GELATIN CASTED FILMS PREPARED FOR ACTIVE PACKAGING

Food packaging is a passive barrier that protects food against environmental factors such as ultraviolet light, oxygen, water vapor, pressure, heat, chemical, and microbiological contaminants. In a changing and developing world, consumers now want to reach healthier, fresher, and more diverse foods. In response to consumer demands and expectations, the food sector has focused on developing active and intelligent packaging. The purpose of active packaging is to protect the properties of the food by interacting with the coating material and prolonging the shelf life. In this context, it is aimed to prepare active package films by integrating bioactive agents into films prepared based on biodegradable polymers. It is an important point that is determined how the characteristics of the films such as morphology, molecular structure, surface property, and antimicrobial activity, will shift depending on the type and quantity of bioactive agent addition. Based on this, packaging films loaded with different concentrations of orange peel essential oil (OEO) (25, 50 and 100% of total polymer weight) were produced on the basis of chitosan and gelatin natural polymers. The changes that occur in the active films as a result of the increasing amounts of oil were revealed by determining the molecular structure, surface property, morphological characteristics, solubility quality, and antibacterial activity. The solubility of the films, which is an effective parameter in the evaluation of the environmental impact of the films that will be released as waste after use, varied between 20% and 25% at the end of 48 hours. The 100OEO@CH:GEL film showed the highest antibacterial properties against Escherichia coli and Staphylococcus aureus.

Characterization of Aloe Vera Gel-Based Edible Coating with Orange Peel Essential Oil and Its Preservation Effects on Button Mushroom (Agaricus bisporus)

In the present study, the effects of orange peel essential oils (EOs) on the physiochemical, rheological, particle size and zeta potential distribution of the developed aloe vera gel-based edible coating were investigated. We also investigated the effects of prepared aloe vera gel-based edible coating (with or without incorporation of orange peel essential oil) on the postharvest shelf life and characteristics such as physiological loss of weight (PLW), color, respiration rate, firmness, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and antimicrobial activity of button mushroom (Agaricus bisporus) at 4 °C during 16 days of storage. The results revealed that the 50% concentration of aloe vera gel-based edible coating without addition of essential oil had significantly superior properties with higher stability zeta potential (− 9.7 mV) as compared to other concentrations of aloe vera gel-based formulation. It also showed the highest potential to maintain the postharvest quality attributes of mushrooms throughout storage. The maximum concentration of orange peel essential oil (1500 µL/L) incorporated in the 50% aloe vera gel (F3)-based treatment significantly improved the postharvest quality attributes of mushrooms as compared to coating prepared with incorporation of 500 µL/L and 1000 µL/L concentration of EOs (orange peel essential oils) and helped extend the shelf life of mushrooms up to 4 days as compared to the control (50% AV (aloe vera gel) only). Further research should be performed to develop water and gas barrier composite edible coatings to further extend mushroom shelf life.

Novel Benzothiazole Derivatives as Potential Anti-Quorum Sensing Agents for Managing Plant Bacterial Diseases: Synthesis, Antibacterial Activity Assessment, and SAR Study

As quorum sensing (QS) regulates bacterial pathogenicity, antiquorum sensing agents have powerful application potential for controlling bacterial infections and overcoming pesticide/drug resistance. Identifying anti-QS agents thus represents a promising approach in agrochemical development. In this study, the anti-QS potency of 53 newly prepared benzothiazole derivatives containing an isopropanolamine moiety was analyzed, and structure-activity relationships were examined. Compound D3 exhibited the strongest antibacterial activity, with an in vitro EC50 of 1.54 μg mL-1 against Xanthomonas oryzae pv oryzae (Xoo). Compound D3 suppressed QS-regulated virulence factors (e.g., biofilm, extracellular polysaccharides, extracellular enzymes, and flagella) to inhibit bacterial infection. In vivo anti-Xoo assays indicated good control efficiency (curative activity, 47.8%; protective activity, 48.7%) at 200 μg mL-1. Greater control efficiency was achieved with addition of 0.1% organic silicone or orange peel essential oil. The remarkable anti-QS potency of these benzothiazole derivatives could facilitate further novel bactericidal compound development.

Valorization of essential oils from citrus peel powder using hydro-distillation

Citrus species exhibit many important natural bioactive compounds, such as ascorbic acid, essential oils, and antioxidant substances. Citrus essential oils are a complex mixture of volatile and non-volatile compounds obtained from the citrus fruit peel, which are discarded as waste. These citrus peels are a rich source of essential oils having medicinal benefits such as antioxidant, anticancer, antidiabetic, and anti-inflammatory properties. An experiment was carried out on two Citrus species (Citrus reticulata cv. (kinnow) and Citrus X sinensis (orange)) peel powder to study the essential oil composition. The kinnow and orange peels were dried using the sun and tray drying method and were compared. The peel powder obtained by sun and tray drying was tested for antioxidant activity (DPPH assay, TPC activity, and ascorbic acid activity). The essential oil was extracted from peel powder using a sustainable hydro-distillation technique. The results revealed that the highest yield was obtained in tray-dried orange peel powder (9.98%), followed by tray-dried kinnow peel powder (9.70%). The bioactive composition of the extracted essential oils was analyzed by gas chromatography-mass spectrometry (GC-MS). The kinnow and orange peel essential oil composition was predominated with d-limonene, terpenoids, and sesquiterpenes, enhancing its medicinal value. Thus, this study developed a green, sustainable, and eco-friendly hydro-distillation technique for citrus essential oil extraction.

The effectiveness of roll-on aromatherapy of calamansi orange peel essential oil (Citrofortunella microcarpa) on reducing anxiety and pain in labor

Purpose: To determine the effectiveness of calamansi orange peel aromatherapy in reducing pain and anxiety in the active first stage of labor. Patients and methods: This research is a quasi-experimental pre-posttest control group design. The number of samples was 60 people, 30 mothers for each intervention and control group. Samples were obtained by accidental sampling from 10 independent Privat Midwifery Clinics in Bengkulu and divided into 2 groups randomly. Pain level was assessed by VAS, and anxiety level was measured by HARS. Data were collected before the intervention (pre-test and after the intervention (post-test) 1 (dilatation 4), post-test 2 (dilatation 7-8 cm), and post-test 3 (dilatation 9-10). Meanwhile, the level of anxiety was only measured 2 times during the pre-test and post-test (dilatation 4). The results were analyzed using the Wilcoxon signed rank test and the Mann-Whitney U test. Results: The results showed that in the intervention group, it was known that there was an effect of giving calamansi orange peel aromatherapy on pain (0.001) and anxiety (0.001) in mothers in the active phase of the first stage of labor. In the control group given orange aromatherapy, the results also showed an effect on pain (0.005) and anxiety (0.046). The results of the Mann-Whitney U test showed that there was a significant difference between the intervention and control groups in post-test 1 (0.000) and post-test 2 (0.004), but there was no significant difference in post-test 3 (0.121). Meanwhile, for the level of anxiety, it is known that there is a difference between the intervention and control groups (0.042). Conclusion: Using aromatherapy of calamansi orange peel essential oil as a complementary therapy effectively reduces the level of pain and anxiety in mothers during the active phase of the first stage of labor.

Uji Aktivitas Antibakteri Minyak Atsiri Kulit Jeruk Pontianak (Citrus nobilis Lour. var. microcarpa) terhadap Bakteri Staphylococcus aureus dan Staphylococcus mutans

Antibacterial is a substance that can inhibit the growth of bacteria and can kill bacteria that cause infection. Currently increasing resistance to antibiotics is an opportunity to utilize bioactive compounds from the diversity of plants in Indonesia, one of which is by utilizing Pontianak orange peels. Based on some literature, it is stated that essential oils from Pontianak orange peels can inhibit the growth of several types of bacteria. In this study, antibacterial tests were carried out on S.aureus and S.mutans bacteria. The essential oil of Pontianak orange peel was first tested for phytochemical screening and then an antibacterial test was carried out with several concentrations of 5%, 10%, 25%, and 50%, the antibacterial activity test was carried out using the disc diffusion method. The results of the phytochemical screening test showed that the essential oil of Pontianak orange peel contains flavonoids, saponins, and terpenoids. Furthermore, in testing the S.aerues bacteria, the essential oil of orange peel can have an inhibition zone with a range of 9-11 mm which is included in the strong antibacterial category, while in testing the inhibition of S. mutans bacteria, it is included in the moderate category, namely in the range of 7-10 mm. In the statistical test, there was no significant difference in the inhibition of S. mutans and S.aereus bacteria in inhibiting the growth of the orange peel essential oil as indicated by the diameter of the inhibition zone in the different treatment groups according to the concentration of orange peel essential oil.

In vitro and in vivo antifungal and immune stimulant activities of oregano and orange peel essential oils on Fusarium solani infection in whiteleg shrimp

In vitro and in vivo antifungal and immune stimulant activities of oregano and orange peel essential oils on Fusarium solani infection in whiteleg shrimp

Comparative GC Analysis of Valencia orange Ripe and Unripe Peel Essential Oils, Nano-formulation, Anti-Helicobacter Pylori and Anti-inflammatoryEvaluation: in vitro and in silico

Peptic ulcer associated with H. pylori infection and antibiotics resistance warranted the execution of the foregoing study to produce natural and safe alternatives. GC-MS analysis of the essential oil derived from the ripe and unripe peel of Citrus sinensis var. Valencia grown in Egypt was investigated besides its anti-Helicobacter pylori and COX-2 inhibition actions. Ripe mature peels displayed a higher oil yield than unripe ones (0.8 and 0.6%, respectively). Twenty-nine compounds were identified in all samples with volatile monoterpenes as the predominant class, (88.90% and 90.62% in fresh ripe peel (P1) and dried ripe peel (P2), respectively, however unripe fresh orange peel (P3) showed a lower quantity (83.95%). D-Limonene was the major compound in P1 and P2 (85% and 88 %, respectively), while 73% were found in P3. In comparison to standard Clarithromycin (MIC90 = 1.95 ± 0.002 μg/ml), the nano-hexosomal formula of P1 reduced H. pylori action more than P1 alone with MIC90= 1.95 ± 0.0029 μg/ml and MIC90= 3.90 ± 0.006 μg/ml for formulated and unformulated P1, respectively. An anti-inflammatory assay via COX-2 inhibition revealed that the formulated P1 is more potent (IC50= 0.85 μg/ml) than P1 alone (IC50= 2.04 μg/ml) in comparison with Celecoxib® (IC50= 0.28 μg/ml). To unravel the mechanism of the anti-Helicobacter pylori activity, an in silico study on D-Limonene has been performed, using H. pylori urease enzyme, which revealed that D-Limonene showed promising binding scores. Thus, Valencia orange peel essential oil offers a natural, cheap, and relatively safe candidate to combat Helicobacter pylori infection.

Chemical Composition and Physical Characteristics of Orange Peel Essential Oil

The citrus-based food and beverage industry is limited to using fruit flesh as the main raw material. Orange peels that cannot be utilized are disposed of as waste. The potential of citrus peel is very high to be processed into essential oil. Essential oils are widely used in the pharmaceutical, food, and agricultural industries. Various citrus varieties in Indonesia have different characteristics, including the content of essential oils in peel waste. The process of making essential oils can be done by distillation. This research was conducted to find out the chemical and physical of various essential oils from citrus varieties (RGL Mandarin, Gamindo B, and Montaji Agrihorti lemon). The test results show that the yield of each essential oil of RGL Mandarin, Gamindo B, and Montaji Agrihorti lemon is 3,866%; 1,174%; and 3,615%. The volatile compound content tested using GC-MS in Gamindo B citrus essential oil contained 3 compounds, RGL Mandarin found 4 compounds, and Montaji Agrihorti lemons found 4 compounds. A sensory preference test on color and odor attributes was conducted on 30 panelists. Montaji Agrihorti Lemon essential oil is the most preferred by color and Gamindo B essential oil is the most preferred by odor.

Influence of rootstock, fruit development stage and ploidy level on the yield, composition and aromatic properties of sweet orange peel essential oil

ISHS XXXI International Horticultural Congress (IHC2022): International Symposium on Integrative Approaches to Product Quality in Fruits and Vegetables Influence of rootstock, fruit development stage and ploidy level on the yield, composition and aromatic properties of sweet orange peel essential oil

Effect of Jungga Orange Peel Essential Oil (Citrus Jambhiri) on Platelet Function in Male Rats Given High Intensity Physical Activity

Physical activity is one of the stress factors that can provide physiological changes to the function of the hematological system such as changes in platelet count. Physical activity can produce free radicals that can result in cell damage including platelets. Platelets play a role in the hemostasis process, If the platelet count is too low, it can cause excessive bleeding. However, if there is an increase in platelet count too high, it can cause thrombosis that can inhibit blood vessels. Antioxidants have a protective effect on cells and eliminate free radicals. The objective of this research was to ascertain the reaction of platelets to the injection of jungga orange peel essential oil (citrus jambhiri) in male rats that were subjected to strenuous exercise. Twenty male rats (3-4 months old, 180-200 grams) of the Wistar strain of the white rat (Rattus norvegicus) were used in the experiment. Using a random number generator, 20 white rats were split into two groups. In group P1, the rats swam for 50 minutes, three times a week, for four weeks. In group P2, the rats swam for 50 minutes, three times a week, for four weeks, and were also given 0.05 milliliters of jungga orange peel essential oil every hour prior to swimming. Based on these findings, it appears that there is a statistically significant difference between the P1 and P2 groups in terms of the average platelet count, with the P2 group exhibiting a decline in platelet count. Antioxidant substances contained in the essential oil of jungga orang have the ability to inhibit the decline in platelet function after high-intensity physical activity.

Insecticidal and antifungal effects of lemon, orange, and grapefruit peel essential oils from Argentina

The aim of the present work was to study the bioactivity of lemon, orange, and grapefruit peel essential oils (EOs) obtained from Argentinian plantations on different agronomically important insect and fungal species. The chemical profile of EOs was determined by Gas Chromatography-Mass Spectrometry (GC/MS); the insecticidal activity was studied through contact and fumigant assays; the antifungal activity was evaluated with fumigant tests. Orange EO was the most effective against Rhyzopertha dominica, Oryzaephilus spp. and Sitophilus granarius in fumigation tests (LC50= 89.39, 94.50, and 163.64 µL/L air, respectively); while the insecticidal effect of EOs was species-dependent in contact toxicity assays. Regarding antifungal activity, Rhizoctonia solanii was more susceptible than Sclerotium rolfsii to the tested EOs, with lemon from Industry 1 and orange being the most toxic EOs (MIC=10.77 µL/plate and 11.02 µL/plate, respectively). Conversely, S. rolfsii was strongly inhibited by lemon EO from Industry 2 (MIC= 52.40 µL/plate). Besides limonene, other compounds that could be responsible for these bioactivities were: linalool, carvone, α-pinene, β-pinene, β-myrcene, α-terpineol, terpinen-4-ol, limonene oxide, β-phellandrene, γ-terpinene, sabinene, neral, neryl acetate, β-caryophyllene and p-cymene. Citrus peel EOs can be used against different pests, contributing to the valorization of citrus residues.

Physical Characteristics, Mineral Content, and Antioxidant and Antibacterial Activities of Punica granatum or Citrus sinensis Peel Extracts and Their Applications to Improve Cake Quality.

One-third of all food produced for human use is discarded as waste, resulting in environmental pollution and impaired food security. Fruit peels have bioactive compounds that may be used as antimicrobials and antioxidants, and the use of fruit peels is considered an alternative way to reduce environmental problems and agro-industrial waste. The aim of this study was to evaluate the phytochemical, mineral, extraction yield, total phenolic, total flavonoids, antioxidant, and antibacterial activity of several peel fruits, including Citrus sinensis (orange) and Punica granatum (pomegranate). The results revealed that pomegranate peel powder contains the highest amounts of ash, fiber, total carbohydrates, Ca, Fe, Mg, and Cu, while orange peel contains the highest amounts of moisture, protein, crude fat, P, and K. Furthermore, the aqueous and methanolic pomegranate peel extracts yielded higher total phenolic and total flavonoids than the orange peel extract. The identification and quantification of polyphenol compounds belonging to different classes, such as tannins, phenolic acids, and flavonoids in pomegranate peel and flavonoid compounds in orange peel were performed using UPLC-MS/MS. In addition, GC-MS analysis of orange peel essential oil discovered that the predominant compound is D-Limonene (95.7%). The aqueous and methanolic extracts of pomegranate peel were proven to be efficient against both gram-positive and gram-negative bacteria linked to human infections. Sponge cake substituting wheat flour with 3% pomegranate peel and 10% orange peel powder had the highest total phenolic, flavonoid compounds, and antioxidant activity as compared to the control cake. Our results concluded that pomegranate and orange peel flour can be used in cake preparation and natural food preservers.

Physicochemical, antioxidant and antimicrobial properties of citrus peel essential oils

Essential oils are produced as secondary metabolites of aromatic plants and can be extracted from leaves, seeds or fruit peel of the plants. Citrus peel is a rich source of limonene which is antimicrobial in nature. The present study aimed to deal with the physicochemical, antioxidant and antimicrobial properties of citrus peel essential oil from Citrus reticulate (mandarin orange), Citrus limetta (mosambi) and Citrus limon (lemon). The lemon peel oil had lower peroxide value (1.6 meq/kg of sample), saponification value (112.2 mg KOH/g of oil) and higher iodine value (116 gI2/100g oil) when compared with orange and mosambi peel essential oil. DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity of citrus peel essential oil was measured and the result indicated that the total antioxidant activity of lemon peel oil was 89.2 % Radical Scavenging activity (RSA). The antifungal activity was assessed by agar dilution method, whereas the antibacterial property was assessed by the agar diffusion method. Lemon peel oil recorded better antimicrobial properties with minimum inhibitory concentration of 0.3% against Aspergillus flavus MTCC 277, 0.2% for Penicillium MTCC 1995 and Fusarium oxysporum MTCC 284. Likewise, the minimum inhibitory concentration of lemon peel oil against Staphylococcus aureus MTCC 96 was 0.3%; Salmonella enterica MTCC 733 and Erwinia sp MTCC 2760 was 0.5%; Pseudomonas aeruginosa MTCC 1688 and Escherichia coli MTCC 443 was 0.7%. This comparative study showed that lemon peel oil had better physicochemical and antioxidant property. Lemon peel oil can be used as a preservative in the food system as it exhibited antibacterial and antifungal activity.

Recovery of Orange Peel Essential Oil from ‘Sai-Namphaung’ Tangerine Fruit Drop Biomass and Its Potential Use as Citrus Fruit Postharvest Diseases Control

In this study, we assessed the quality of essential oil recovered from fruit drop biomass and assessed its usefulness in preventing postharvest diseases in the tangerine ‘Sai-Namphaung’. Greening was the primary cause of the fruit drop, based on the enduring symptoms and occurrence of the disease in the area. Limonene, together with the presence of β-pinene and linalool, was discovered to be prevalent in essential oils of tangerine fruit peel, particularly that of ‘Sai-Namphaung’. Through isolation of citrus postharvest fungi, we were able to identify four genera which were later DNA sequenced using Internal Transcribed Spacer: ITS and subjected to Basic Local Alignment Search Tool (BLAST), with a high possibility (>98% similarity) of being Penicillium digitatum, Colletotrichum gloeosporioides, Fusarium sarcochrum and Geotrichum candidum. Essential oil from ‘Sai-Namphaung’ and ‘Fremont’ peel biomass positively inhibited green mold rot and citrus anthracnose caused by P. digitatum, C. gloeosporiodes, but were less effective than the commercial citrus oil and Zanthoxylum myriacanthum oil. This is the first evidence of ‘Sai-Namphaung’ postharvest diseases caused by these two fungi and their controls using citrus essential oil.

Influence of Heating on Thermal Stability of Essential Oils During Storage

Volatile oils are natural products with high antioxidant activity but their chemical composition and antioxidant activities may change due to the thermal storage conditions. In the present study, the changes in antioxidant activity and thermal stability of bay laurel, lemon peel, and orange peel essential oils stored at refrigerator temperature (4°C), room temperature (20°C), and elevated temperature (37°C) for 12 months were examined. In the determination of antiradical activity measured using DPPH method at the beginning of storage, the bay laurel essential oil (82.82%) showed a better inhibition percentage when compared to lemon (32.30%) and orange (46.52%) peel oils. During the storage, a decrease was observed in the antioxidant and antiradical activity values of the oils. The aromatic compositions of volatile oils were determined using GC/MS and the main components of volatile oils were found to be 1,8 Cineolene (50.4%) for bay laurel, d-limonene (80.1%) for lemon peel, and d-limonene (94.6%) for orange peel. At the end of this study, it was found that the change in the compositions of essential oil samples stored in the refrigerator was at a lower level, whereas significant changes were observed in both volatile compositions and antioxidant activity values of the samples stored at elevated temperatures. Moreover, it was also observed that the volatile oils obtained might form natural potential agents that can be used as antioxidant in food products.