Essential Oil Composition of Diploid and Tetraploid Clones of Ginger (Zingiber officinale Roscoe) Grown in Australia

Ginger oil, obtained by steam distillation of the rhizome of Zingiber officinale Roscoe, is used in the beverage and fragrance industries. Ginger oil displays considerable compositional diversity, but is typically characterized by a high content of sesquiterpene hydrocarbons, including zingiberene, arcurcumene, â-bisabolene, and â-sesquiphellandrene. Australian ginger oil has a reputation for possessing a particular “lemony” aroma, due to its high content of the isomers neral and geranial, often collectively referred to as citral. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were steam distilled 7 weeks post-harvest, and the resulting oils were analyzed by GC-MS. The essential oils of 16 of the 17 clones, including the tetraploid clones and their parent cultivar, were found to be of substantially similar composition. These oils were characterized by very high citral levels (51-71%) and relatively low levels of the sesquiterpene hydrocarbons typical of ginger oil. The citral levels of most of these oils exceeded those previously reported for ginger oils. The neral-to-geranial ratio was shown to be remarkably constant (0.61 ( 0.01) across all 17 clones. One clone, the cultivar “Jamaican”, yielded oil with a substantially different composition, lower citral content and higher levels of sesquiterpene hydrocarbons. Because this cultivar also contains significantly higher concentrations of pungent gingerols, it possesses unique aroma and flavor characteristics, which should be of commercial interest.

Geographic and Phenotypic Variation in Heartwood and Essential-Oil Characters in Natural Populations of Santalum austrocaledonicum in Vanuatu.

Phenotypic variation in heartwood and essential-oil characters of Santalum austrocaledonicum was assessed across eleven populations on seven islands of Vanuatu Trees differed significantly in their percentage heartwood cross-sectional area and this varied independently of stem diameter The concentrations of the four major essential-oil constituents (alpha-santalol, beta-santalol. (Z)-beta-curcumen-12-ol, and cis-nuciferol) of alcohol-extracted heartwood exhibited at least tenfold and continuous tree-to-tree variation Commercially important components alpha- and beta-santalol found in individual trees ranged from 0 8-47% and 0-24 1%, respectively, across all populations, and significant (P < 0 05) differences for each were found between Individual populations. The Erromango population was unique in that the mean concentrations of its monocyclic ((Z)-beta-curcumen-12-ol and cis-nuciferol) sesquiterpenes exceeded those of Its bi- and tricyclic (alpha- and beta-santalol) sesquiterpenes Heartwood colour varied between trees and spanned 65 colour categories, but no identifiable relationships were found between heartwood colour and alpha- and beta-santalol, although a weak relationship was evident between colour saturation and total oil concentration These results indicate that the heartwood colour is not a reliable predictive trait for oil quality The results of this study highlight the knowledge gaps in fundamental understanding of heartwood biology in Santalum genus The intraspecific variation in heartwood cross-sectional area. oil concentration. and oil quality traits is of considerable importance to the domestication of sandalwood and present opportunities for the development of highly superior S austrocaledonicum cultivars that conform to the industry's International Standards used for S album.

Screening selected myrtaceous tree species for production of essential oils in northern Queensland

Trials to identify alternative cropping options to Melaleuca alternifolia for northern Queensland essential oil growers were established at Dimbulah and Innot Hot Springs in 2001. Seed sources of Asteromyrtus symphyocarpa (1,8-cineole form), Eucalyptus staigeriana (citral), Melaleuca cajuputi subsp. cajuputi (trans-nerolidol), M. ericifolia (d-linalool), M. quinquenervia (trans-nerolidol and viridiflorol forms) and M. viridiflora (methyl cinnamate) with potential to produce commercial foliar oils were evaluated. Information was gathered on their adaptability, growth and oil yields over 49 months and 52 months (two harvests) from planting at Dimbulah and Innot Hot Springs, respectively. Of the species and chemotypes evaluated, M. quinquenervia showed potential for commercial production of trans-nerolidol, a compound used in perfumery. It had a very high survival rate (96%) and yields could be expected to improve dramatically from the average 100 kg/ha per harvest achieved in these trials with further research into selection of seed source, control of insect damage and breeding for genetic improvement. M. cajuputi subsp. cajuputi gave a similar performance to M. quinquenervia. The rarity of the trans-nerolidol form of this species and remoteness of its natural occurrence are impediments to further planting and research. E. staigeriana, with second harvest yields of ~600 kg/ha, performed exceptionally well on both sites but potential for development is limited by the ready availability of competitively priced E. staigeriana oil produced in South America. Survival of M. ericifolia ranged from 62% to 82% at 32 months (second harvest) at Innot Hot Springs and was deemed a failure at Dimbulah with poor growth and low survival, raising a major question about the suitability of this species for cultivation in the seasonally dry tropics. Planting of this species on a wider scale in northern Queensland cannot be recommended until more is known about factors affecting its survival. A. symphyocarpa and M. viridiflora were too slow-growing to warrant further consideration as potential oil-producing species at this time.

Infection by Alternaria alternata causes discolouration of Backhousia myrtifolia foliage and flowers.

The pathogenicity of three isolates of Alternaria alternata from Backhousia myrtifolia leaves was characterised and compared. Isolate BRIP 52222 was virulent compared to isolates BRIP 52223 and BRIP 52221. A comparison of inoculation methods showed that abrasion was more effective at establishing an infection than puncture wounding. Koch's postulates were assessed to confirm the pathogenicity of A. alternata on B. myrtifolia foliage and floral tissues using a conidial suspension of the most virulent isolate. Sporulation was triggered by incubating A. alternata (BRIP 52222) at 28 degrees C for 10 d under alternating 12 h black-light/12 h dark conditions on half-strength potato dextrose agar (PDA). In contrast, incubation of A. alternata under continuous black-light on either half- or full-strength PDA did not yield conidia. Host symptoms caused by inoculation with the pathogen included a brown-black discolouration of both foliage and floral tissues. Microscopic examination of cellular structures suggested that perturbation of oil glands may contribute to the tissue discolouration in B. myrtifolia caused by A. alternata infection. Oil gland structures can be disrupted during an active A. alternata infection, causing the leakage of essential oil followed by discolouration.

Effect of Packaging Materials and Storage on Major Volatile Compounds in Three Australian Native Herbs

Lemon myrtle, anise myrtle, and Tasmanian pepper leaf are commercial Australian native herbs with a high volatile or essential oil content. Packaging of the herbs in high- or low-density polyethylene (HDPE and LDPE) has proven to be ineffective in preventing a significant loss of volatile components on storage. This study investigates and compares the effectiveness of alternate high-barrier property packaging materials, namely, polyvinylidene chloride coated polyethylene terephthalate/casted polypropylene (PVDC coated PET/CPP) and polyethylene terephthalate/polyethylene terephthalate/aluminum foil/linear low-density polyethylene (PET/PET/Foil/LLDPE), in prevention of volatile compound loss from the three native herbs stored at ambient temperature for 6 months. Concentrations of major volatiles were monitored using gas chromatography?mass spectrometry (GC-MS) techniques. After 6 months of storage, the greatest loss of volatiles from lemon myrtle was observed in traditional LDPE packaging (87% loss) followed by storage in PVDC coated PET/CPP (58% loss) and PET/PET/Foil/LLDPE (loss of 23%). The volatile loss from anise myrtle and Tasmanian pepper leaf stored in PVDC coated PET/CPP and PET/PET/Foil/LLDPE packaging was <30%. This study clearly indicates the importance of selecting the correct packaging material to retain the quality of herbs with high volatile content.

Combinations of plant-derived compounds against Campylobacter in vitro

Campylobacter occur in fresh retail poultry products as a result of their colonization of the gastro-intestinal tract of chickens during growth. Feed additives could be used for suppression of Campylobacter levels in the chickens prior to slaughter. To address this opportunity, feed manufacturers are targeting natural antimicrobials from plant material as new forms of consumer-accepted feed additives. However, to be practical, these natural antimicrobials must be effective at low concentrations. The current study has validated an improved laboratory method to study minimal inhibitory concentrations of plant compounds and their combinations against Campylobacter. The assay was shown to be valid for testing lipid-soluble and water-soluble plant extracts and byproducts from the food industry. The study screened 29 extracts or plant-derived compounds and their mixtures for anti-Campylobacter activity using a laboratory assay. Combinations of oregano, lactic acid, and sorghum byproduct showed effective synergy in anti-Campylobacter activity. The synergies allowed a large reduction in the concentration of the individual compounds needed to kill the bacteria with an 80% reduction in concentration being achieved for oregano essential oil. The assay gives rise to further opportunities for the testing of a greater range of combinations of plant-derived compounds and other natural antimicrobials. The method is robust, simple, and easily automated, and it could be used to adjust the cost of feed formulations by reducing costs associated with antimicrobial feed additives.

Anise Myrtle (Syzygium anisatum) Oils

Syzygium anisatum (formerly Backhousia anisata and Anetholea anisata) is an Australian rainforest tree with leaves that produce an essential oil (EO) that has the characteristic aroma of aniseed. It is referred to as aniseed myrtle or anise myrtle in the trade and the fresh and dried leaves of this plant are used as a herb in culinary applications. The EO is extracted by steam distillation of the leaves and the major aromatic volatile compound is anethole. The EO has broad spectrum antimicrobial activity but is more effective against bacteria than fungi. Indigenous Australians have used anise myrtle for its medicinal values and in recent times it has been used as a flavoring agent by the food and beverage industry. This chapter covers the use of anise myrtle EO in food and agricultural applications, botanical aspects, and chemical composition.

Lemon Myrtle (Backhousia citriodora) Oils

Lemon myrtle has been traditionally used by indigenous Australians for cooking and healing. More recently, lemon myrtle leaves are used as a dry or fresh herb in food applications and the essential oil (EO) used as a flavoring agent in food and beverages. The leaf of the lemon myrtle (Backhousia citriodora) is steam distilled to produce the EO. Lemon myrtle EO is known for its characteristic lemon flavor and the major chemical component contributing to the aroma is citral. The EO has broad spectrum antimicrobial activity and is very effective against fungi and has increased the potential of using the EO in food preservation and treatment of postharvest diseases in fruits. This chapter covers the use of lemon myrtle EO in food and agriculture applications, general usage, botanical aspects, and chemical composition.

Tasmanian Pepper Leaf (Tasmannia lanceolata) Oils

Tasmannia lanceolata, commonly known as Tasmanian pepper leaf or mountain pepper, is an Australian native plant that produces an essential oil with a characteristic pungent flavor attributed to the sesquiterpene polygodial. The dried and fresh leaves are used in culinary applications. The essential oil is produced by a solvent extraction process, and the resultant concrete is a rich source of the principal pungent molecule polygodial and other volatiles. The Tasmanian pepper leaf extract has broad-spectrum antimicrobial activity and is very effective against fungi, especially yeasts. This demonstrates its potential to be used in the food industry as a natural preservative. Indigenous Australians have used Tasmanian pepper leaves for therapeutic purposes; in recent times, it is been used as a flavoring agent and enhancer of pungency in food products. This chapter covers the use of Tasmanian pepper leaf essential oil in food applications, its botanical aspects, and its chemical composition.

Effect of citrus peel chemicals on Bactrocera tryonilarval survival

Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is a major horticultural insect pest in Australia which significantly limits domestic and international market access for Australian horticultural produce. Citrus is one of the industries seriously affected by the fruit fly problem in Australia. This research investigated the effect of citrus peel essential oil chemicals on B. tryoni larval survival in five different commercially important Citrus species and cultivars as a way of better understanding fruit susceptibility. The fruits used were Murcott Mandarin, Navel orange, Eureka lemon, Valencia orange and yellow grapefruit. The essential oils of each citrus type were extracted using hydrodistillation and then mixed, at different concentrations, with artificial larval diets to which B. tryoni eggs were added. Surviving larvae were counted after five trial days. The same process was repeated for six essential oil components. Regression analysis of increasing oil concentration against larval survival showed that the crude oil blends of Navel orange, Eureka lemon and yellow grapefruit had significant negative effects on B. tryoni larval survival, but no such effects were seen for Murcott Mandarin and Valencia orange. Of the individual essential oil fractions, only D-limonene had a significant effect on B. tryoni larval survival, with this chemical being highly toxic at very low concentrations. The results of this study open up opportunities for incorporating B. tryoni resistance mechanisms into citrus through minor peel property changes which would not impact on the eating attributes of the fruit.

The determination of essential oils in Sandalwood via NIR Spectroscopy

Sandalwood oil is widely used in the medicinal, cosmetic and aromatherapy industries. The oil is distilled from the heartwood of the sandalwood tree Santalum - a genus of hemi-parasitic tree species occurring throughout South and Southeast Asia, Australia and the Pacific. With international concern on the sustainability Sandalwood oil (Fox, 2000), the quality of oil entering the market is being compromised either through extraction from underdeveloped heartwoods or through adulteration with lower grade Sandalwood oils or synthetic substitutes (Howes et al. 2004). Although no standard method exists to assess the quality of Sandalwood oil, the International Organisation for Standardisation recommends GCMS analysis of santalol oil content. NIR spectroscopy has had a demonstrated success for other essential oils (Schulz et al. 2004, Steur et al. 2001). In addition, NIR spectroscopy has also been applied as both a qualitative and quantitative analytical tool in the forestry industry (Steur et al. 2001). This project aimed to assess the ability of NIR spectroscopy as a non-invasive, rapid and cheap analytical alternative to GCMS for Santalol determination.

Near infrared reflectance as a rapid and inexpensive surrogate measure for fatty acid composition and oil content in peanuts (Arachis hypogaea L.)

The fatty acid composition of ground nuts (Arachis hypogaea L.) commonly known as peanuts, is an important consideration when a new variety is being released. The composition impacts on nutrition and, importantly, self-life of peanut products. To select for suitable breeding material, it was necessary to develop a rapid, non-derstructive and cost-efficient method. Near infrared spectroscopy was chosen as that methodology. Calibrations were developed for two major fatty-acid components, oleic and linoleic acids and two minor components, palmitic and stearic acids, as well as total oil content. Partial least squares models indicated a high level of precision with a squared multiple correlation coefficient of greater than 0.90 for each constitutent. Standard errors for prediction for oleic, linoleic, palmitic, stearic acids and total oil content were 6.4%, 4.5%, 0.8%, 0.9% and 1.3% respectively. The results demonstrated that reasonable calibrations could be developed to predict oil composition and content of peanuts for a breeding programme.

The essential and non-essential genes of Bovine herpesvirus 1

Bovine herpesvirus 1 (BoHV-1) is an economically important pathogen of cattle associated with respiratory and reproductive disease. To further develop BoHV-1 as a vaccine vector, a study was conducted to identify the essential and non-essential genes required for in vitro viability. Randominsertion mutagenesis utilizing a Tn5 transposition system and targeted gene deletion were employed to construct gene disruption and gene deletion libraries, respectively, of an infectious clone of BoHV-1. Transposon insertion position and confirmation of gene deletion were determined by direct sequencing. The essential or non-essential requirement of either transposed or deleted open reading frames (ORFs) was assessed by transfection of respective BoHV-1 DNA into host cells. Of the 73 recognized ORFs encoded by the BoHV-1 genome, 33 were determined to be essential and 36 to be non-essential for virus viability in cell culture; determining the requirement of the two dual copy ORFs was inconclusive. The majority of ORFs were shown to conform to the in vitro requirements of BoHV-1 homologues encoded by human herpesvirus 1 (HHV-1). However, ORFs encoding glycoprotein K (UL53), regulatory, membrane, tegument and capsid proteins (UL54, UL49.5, UL49, UL35, UL20, UL16 and UL7) were shown to differ in requirement when compared to HHV-1-encoded homologues.

Controlling fly strike and louse infections in sheep with tea tree oil

This study aimed to assess the effect of tea tree oil based formulations against two major ectoparasitic diseases in the sheep industry, flystrike and louse infestation, and to provide data to assist the assessment of the commercial feasibility of development of tea tree oil based ectoparasiticides. The results demonstrate insecticidal effects against both sheep lice and blowflies and repellent effects against adult flies and maggots. Dipping sheep in a Tea Tree Oil based formulation appeared to completely eradicate lice and suggests its potential use in sheep dipping formulations. Repellent and insecticidal effects against sheep blowflies, together with previously reported anti-microbial and wound healing properties, suggest significant benefits from the inclusion of tea tree oil in flystrike and wound treatment formulations. These effects occurred at concentrations of Tea Tree Oil that suggest the commercial viability of development of Tea Tree Oil based formulations for sheep parasite control and wound treatment and a potential new market for Tea Tree Oil.

Use of tea tree oil against buffalo flies in cattle

Testing tea tree oil against buffalo flies on cattle.