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Rural Industries
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Control of mint rust (Puccinia menthae) on peppermint – epidemiology and chemical control
Objectives
Mint rust is caused by a rust fungus that has a complicated life cycle involving five spore types. This cycle, as it occurs in NE Vic, has been studied for 4 years now and it is evident that only two spore types occur, of which the summer spore remains viable throughout winter and carries the disease into the next season. Experiments have been undertaken examining the effects of temperature and leaf wetness on the infection process. Optimum conditions are at least six hours of leaf wetness and temperatures of 15º - 20ºC. Below 15ºC the fungus is inhibited, and above 27ºC it is killed. Control measures should therefore begin early in the season.
There is a lot of variation within the fungus population. At least 8 races have been identified from 18 collections of rust, and there are clear differences between those races which attack peppermint and those which attack spearmint.
Of six fungicides trialed on Scotch spearmint over the past 2 years, Baycor and Foliar performed best under Victorian conditions. It is hoped that these results can also be applied to Peppermint
RIRDC Project No: UM-16A
Start Date: 1 July, 1993
Finish Date: 30 September, 1998
Researcher: Dr. Gerald Halloran
Organisation: The University of Melbourne, Royal Parade, PARKVILLE VIC 3052
Contacts: Phone: (03) 9344 7128 Fax: (03) 9344 5570
Generation of high quality Australian Echinacea products
Objectives
Analytical methods using HPLC to determine the level of alkylamides and caffeoyl phenols in echinacea extracts have been established and a routine service is now available to the industry. Examination of changes in these active constituents during growth shows the major concentration of active constituents is in the roots followed by the flowers and lowest in the stems and leaves. The concentration of active constituents was relatively constant over the growing period with some decline in over-mature plants during senescence. It seems that an increase in plant size is beneficial as the concentration of active constituents is not decreased during the additional plant growth. Preliminary studies of changes in active constituents during processing to obtain a liquid extract and subsequent concentration or drying showed considerable losses of active constituents during both extraction and subsequent concentration and drying.
RIRDC Project No: UNC-4A
Start Date: 1 September, 1996
Finish Date: 30 September, 1998
Researcher: Professor Ron Wills
Organisation: University of Newcastle, Central Coast Campus, PO Box 127, OURIMBAH NSW 2258
Contacts: Phone: (02) 4348 4140 Fax: (02) 4348 4145 E-mail: ftbhw@cc.newcastle.edu.au
Yield & quality of concentrate from Boronia megastigma (Nees)
Objectives
Significant increases in the production of floral extract, volatiles and beta-ionone occurred during post-harvest incubation of freshly harvested flowers at 12-16°C. Oxygen is required and temperature control is crucial, flower respiration appears to be a regulating factor. Clones differ in their post-harvest biosynthetic ability, potential increases being 20% of extract concentration (% dr. wt.), 120% of total volatiles and 190% of beta-ionone. Large scale (150kg) incubations have been successful, producing similar increases and paving the way for improved post-harvest handling techniques on-farm. Optimally harvested flowers (80% open) have the potential to produce more volatiles after harvest than late harvested flowers (90% + open).
The biochemical basis for the increases in extract and volatiles after harvest include hydrolysis of glycosidically bound volatiles or de novo synthesis. The former appears to be most likely; identification of potential precursors and hydrolytic enzymes is being pursued. There is an increase in the range of volatile compounds released from standard extracts by hydrolysis with enzymes made from flower material more advanced than 75% open flowers, suggesting that hydrolysis of glycosides is a natural part of flower senescence.
RIRDC Project No: UT-10A
Start Date: 1 August, 1995
Finish Date: 30 October, 199
Researcher: Professor Robert Menary
Organisation: University of Tasmania, GPO Box 252C, HOBART TAS 7001
Contacts: Phone: (03) 6226 2723 Fax: (03) 6226 7609 E-mail: r.menary@utas.edu.au
A new commercial flavour product from Tasmannia lanceolata
Objectives
A variety of extracts of T. lanceolata were sent to Toyotama and have been assessed by Dr. Ishizuka. Clones FG1, GL6, HY9 and PP1 rated well in terms of flavour and spice characteristics. For their current purposes, PP1 and TR5 were determined to be the most useful.
Principle co-ordinate analysis and cluster analysis were used to provide an insight into the chemical relatedness of plants within a localised area. A paper dealing with this work has been accepted for publication by the Journal of Agricultural and Food Chemistry.
Safrole concentrations in leaves have been followed throughout the season.
Chemical characterisation of the Native Pepper extract has identified over 75% of the components, including most of the major constituents. A new HPLC/MS/MS system will be commissioned by the CSL early in June. Our separatory methods will be transferred to the new system, where the further identification of unknowns will proceed.
A new method for screening clones for temperature tolerance is being investigated. The collection of 140 clones is being maintained in a nursery clone bank.
A report from the marketing company, EOT, suggests that the process of product registration has been initiated, and we are waiting for a response from FEMA.
Note: This report relates to the modified objectives as agreed in October 1996.
RIRDC Project No: UT-11A
Start Date: 1 October, 1995
Finish Date: 30 September, 1998
Researcher: Professor Robert Menary
Organisation: University of Tasmania, GPO Box 252C, HOBART TAS 7001
Contacts: Phone: (03) 6226 2723 Fax: (03) 6226 7609 E-mail: r.menary@utas.edu.au
Determination of pesticide minimum residue limits in essential oils
Objectives
Analytical methods have been developed for the herbicides Stomp, Allicide, Solicam, Simazine, Sertin, Krovar, Frontier, Lontrel, Dicamba, MCPA, and Garlon.
The methods have been applied to the analyses of field trials in boronia. Most of the herbicides were translocated into the boronia plant. Those, which produced residues above 5ppm, were rejected for inclusion in future studies.
Oils produced by the major growers in the industry in 1996 and 1997 have been screened for the presence of residues of Tilt and Nuvacron. No residue problems are evident for Nuvacron. However, problems still exist within the industry with respect to residues of the active ingredient of Tilt, propiconazole.
Studies to determine the stability of pesticides in peppermint and boronia under storage have been completed. Field trials of Folicur in boronia show that the degradation of the fungicide in boronia is markedly lower than that already determined in peppermint crops. In addition samples of boronia treated with Tilt were collected and a comparative rate of the degradation of Tilt and Folicur has been established.
A paper dealing with the dissipation of propiconazole and tebuconazole in Peppermint Crops and their Residues in Distilled has been submitted to the 'Journal of Agriculture and Food ChemistryÆ.
RIRDC Project No: UT-13A
Start Date: 1 July, 1996
Finish Date: 30 September, 1998
Researcher: Professor Robert Menary
Organisation: University of Tasmania, GPO Box 252C, HOBART TAS 7001
Contacts: Phone: (03) 6226 2723 Fax: (03) 6226 7609 E-mail: r.menary@utas.edu.au
Maximising of yield and productivity of peppermint through double harvesting
Objectives
Peppermint oil is used as a flavouring in toothpaste, chewing gum and confectionery and approximately 5000 tonne per year is consumed world-wide of which Australia imports about 60 tonne p.a. This research project is investigating means to increase the yield of our peppermint crops through having tow harvests per season. This research on double harvesting has been carried out on plots on research stations and on commercial crops. The main effects studied are the timing of the first and second harvests and use of nitrogen fertilisers. Preliminary results show that the oil from both the first and second harvests are complete mature oils of high quality. However achieving sufficient yield from the second harvest is proving difficult and requires further research.
RIRDC Project No: VMP-1A
Start Date: 1 October, 1996
Finish Date: 30 September, 1998
Researcher: Dr. Leo Cahill
Organisation: VicMint Partners Pty Ltd, 87 The Crescent, ASCOTVALE VIC 3032
Contacts: Phone: (03) 9375 2985 Fax: (03) 9326 2326
Developing essential oils of honeydew melon, carrot and spinach for export
Objectives
Tall spinach varieties are high yielding, suited to machine processing, with overseas market demand for their juice flavour and aroma. Dedicated spinach processing crops are achievable if harvesters and herbicides for broadleaf weeds are developed to reduce labour costs. Short, hand harvested, spinach varieties are preferred by the fresh market. Methods to reduce high sodium in spinach juice are required through management of fertiliser, irrigation and planting time. Spinach maturing by spring, has better quality due to reduced aphid-spread Cucumber Mosaic Virus, and bolting.
Honeydew and muskmelon juice and aroma have overseas market demand. Production costs are high and fruit perishable and bulky. Processing local, fresh market reject fruit reduces costs and transport, but production is variable. Melons with tight maturities, enabling a once-over-pick are preferred and require further development. Extraction equipment to exclude skins, and methods to reduce pH in juice are being developed, as markets reject off-flavours and additives.
Overseas demand for carrot juice has declined due to surplus. If markets redevelop, processors are well placed to use the 20-30% overrun fresh market carrots for juice and aroma extraction.
The final report is now completed and under peer review to reach RIRDC by 31 June 1998.
RIRDC Project No: DAS-39A
Start Date: 1 July, 1994
Finish Date: 31 March, 1998
Researcher: Mrs. Shirlie Sylvia
Organisation: Department of Primary Industries and Resources SA, Loxton Centre, PO Box 411, LOXTON SA 5333
Contacts: Phone: (08) 8585 9123 Fax: (08) 8585 8199
Development of an onion oil industry in Tasmania
Objectives
Start Date: 1 February, 1994
Finish Date: 30 September, 1998
Researcher: Mr. Breven Howe
Organisation: Vecon Pty Ltd, PO Box 417, DEVONPORT TAS 7310
Contacts: Phone: (03) 6428 2108 Fax: (03) 6428 2681
Enantiomeric composition of essential oils
Objectives
In nature, one structural form of an essential oil component will predominate over several possible enantiomers, whereas in synthetic products a racemic mix is generally observed. Chiral columns can elucidate the enantiomeric composition of essential oils to confirm the naturalness of additives.
The feasibility of measuring enantiomeric ratios in commercial essential oils using chiral columns was assessed. Literature, dealing with the enantiomeric excesses (ee) encountered in natural extracts has been coordinated. The retention order of the racemic mix of the standards (-)-menthol, (+)-limonene, (-)-limonene, (±)-?-pinene and ?-pinene, (±)-?-ionone, (±)-terpinen-4-ol, ?-terpineol and racemic mix of menthone isomers were determined by comparison to the GC profiles of essential oils known to contain only one enantiomeric form of the chemicals. Different conditions of pressure, temperature and loading quantities on 20% permethylated ?-cyclodextrin chiral columns were trialed. Separation was achieved for all enantiomeric forms. Elution orders were confirmed for enantiomers of limonene, linalool and terpinen-4-ol. After optimisation using GC FID, the chemical identities were confirmed by GC MSD.
The separation of components of peppermint oil and lavender oil was trialed on the chiral column. Comparison with the purified chemicals available indicated that retention time of enantiomeric form is only slightly affected by the matrix in which it is introduced to the chiral column. MSD proved to be a valuable tool in identifying the presence of other components of essential oil which co elute with the enantiomer of interest.
RIRDC Project No: UT-15A
Start Date: 15 June, 1997
Finish Date: 23 March, 1998
Researcher: Professor Robert Menary
Organisation: University of Tasmania, GPO Box 252-54, HOBART TAS 7001
Contacts: Phone: (03) 6226 2723 Fax: (03) 6226 7609 E-mail: r.menary@utas.edu.au
Investigation of potential new opportunities for commercial liquid CO2 extraction
Objectives
The objective of this preliminary study was to investigate the suitability of using an new liquid CO2 refinery to refine extracts of essential oils for sale in overseas markets. A sample of boronia flowers was solvent extracted using a commercial extraction plant and a good yield of oleoresin was obtained. Samples of this oleoresin has been refined using a laboratory scale liquid CO2 refinery. Various refined samples have been analysed using GC equipment. Results to date have indicated that the CO2 refined product is very clear and generally free of coloured plant compounds. The yields of volatile compounds appear promising and good yields of the ionone were achieved. Suitable refined product samples will be sent to potential overseas customers for market evaluation in the near future. If promising market opportunities are available, more work may be conducted to fine-tune the extraction and refining process to increase the yield and quality of the refined product.
Botanical Resources Australia Pty Ltd (BRA) is currently a major producer, manufacturer and exporter of pyrethrum products to world markets. New plant extract products would complement the existing manufacturing processes such as extraction and refining and will allow BRA to diversify and become a supplier or a range of botanical products.
RIRDC Project No: BRA-1A
Start Date: 15-Sep-1997
Finish Date: 30-Apr-1998
Researcher: Dr. Lee Peterson
Organisation: 9 Rodgers, ICHOLLS RIVULET TAS 7112
Contacts: Phone:
(03) 6295 1897 Fax: (03) 6295 1897
