AIR2-CT92-0818 Extraction of Useful Food and Cosmetic Ingredients of Vegetable Origin.

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AIR Cluster V - Speciality Chemicals : Essential Oil : Fine Chemicals : Pharmaceuticals/Cosmetics : Separation/Fractionation

	Proposal No:	AIR2-CT92-0818
	Date Prepared:	September 1999
	Source:	Final report 1998

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Final report 1998

Summary

Abstract

The main objectives of this project, known as Vegextract was to ascertain the potential of produce originating from non-agricultural land in the semiarid regions of Portugal, as well as of extracts obtained from them, as materials capable of use either as culinary or cosmetic ingredients. The deliverables include four monographs, in each of which the most important data about each of four different herbs is detailed. Their extraction and volatile extract preparation are shown to have been optimised with respect to quality and quantity, under both classical and supercritical extraction schemes. The modelling of this last operation was performed in order to permit reasonable production cost estimates. Information is given about odoriferous as well as antioxidant properties of extracts, and also about the various enzyme treatments that were investigated in order to make extraction easier. In each of these monographs, full details of present and potential production characteristics are presented in a straightforward way so that an interested industrial blender or end-user can pick the information they might need in order to determine whether the Portuguese cultivars investigated are of interest.

Initial entrants for which the degree of industrial interest was not so evident, such as algae and cyanobacteria, were given a less complete overall treatment though regarded as very interesting and with high potential. For these species, deliverables include only publications in scientific journals or. proceedings volumes, as well as the project reports. Results are given for sensory evaluation of three extracts.

It was not plausible to run a commercial operation for any one herb, but the production of extracts from all the herbs seemed a much better proposition, though only marginally attractive.

Introduction

Southern areas of Europe include a relatively high percentage of relatively dry land with poor characteristics for agricultural purposes. In some of these, wild vegetation includes herbs that are used in traditional cooking or in traditional healthcare and cosmetic products. The main reasons for using these herbs are the aroma they transmit and their eventual contribution to the preservation of the material they are blended into against oxidation. Other herbs are also grown in areas where a little more water is available, and provide the unique fragrances that characterise local cuisine. In many instances it is possible to use dry parts of the herb for instance for food flavouring purposes, but this is not the case in cosmetics and perfumery.

Microalgae and cyanobacteria are unicellular species which have for a long time been part of the diet consumed by human populations in many parts of the world. Examples are Chlorella vulgaris used in China and Japan, and Spirulina sp. used near lake Tchad and alkaline lakes in the Andes. The main reason for their use is because of their relatively high protein content, but they may also accumulate lipids which are useful from either a nutritional or cosmetic point of view. Their mass production may be attempted intensively within the completely controlled environment provided by an indoor bioreactor system, or using less sophisticated technologies in simpler, more extensive systems which may in a limit situation resemble salt pans, or may in fact be unused salt pans indeed, with some adaptation work.

The main drawback of the utilisation of vegetable material as such for any of the purposes above can be the fact that due to its intrinsic population variability as well as to innumerable climatic and soil circumstances, the active compounds' concentrations vary. One can thus never be sure of the necessary amount of herb which must be used. The technological alternative consists in finding out how and when the active principle's concentration is higher and to extract it unscathed from the starting material, then to preserve it and blend it into a user friendly and stable form, which can be characterised and tested in prospective applications.

Objectives

The main objective of this project was to look at such herbs and their extracts. The following herbs were investigated in detail:

• Rosmarinus officinallis - yielding both flavourings and deodorised antioxidant extracts
• Origanum virens and Thymus zygis - yielding essential oils or supercritical extracts
• Coriandrum sativum - although this proved exceptionally difficult because the extracts obtained from the fresh plant tended to react and their flavour went off, therefore it was necessary to devise a strategy whereby a new and stable flavouring extract was obtained

Other herbs studied included Thymus capitatus that yielded extracts that had both flavouring and antioxidant properties despite the strong volatility in steam, and Myrtus communes that yielded both an essential oil and an efficient antioxidant extract from the deodourised material, therefore useful at high temperature. In each case extraction methodology, both classical and supercritical, was optimised and the latter modelled. Two micro-organisms were also subject to supercritical extraction.

Activities

Treatment included enzyme pre-treatments, various extractions, characterisation of volatile extracts and determining antioxidant activities as well as the supercritical extraction and scale-up, in addition to sensory evaluation, formulation and cost evaluation. In addition the super critical extraction process was modelled.

The extracts obtained from the herbs were regarded as materials capable of providing ingredients of low or intermediate polarity by way of mild and environmentally friendly extraction procedures, enabling preparation of stable, processable blends. The use of these as either culinary or cosmetic ingredients was investigated. Other work included collection of material, extraction ad characterisation of characterisation of microalgal pigments, extraction and characterisation of vitamins and antioxidants present in lipidic fractions of the various raw materials, and evaluation of products obtained from some of the ingredients. The various herbs used were characterised as to their occurrence and habitats in Portugal, and estimates of production capabilities were made. The diversity of chemotypes was apparent in most cases, and some variability of extracts occurred from year to year.

Results

Stable herbal fractions were thus obtained from Rosmarinus officinallis, Thymus zygis, Origanum virens, Thymus capitatus, Myrtus communes and from Coriandrum sativum leaves. The last three were late entrants, brought into the project because of their popularity among local users for a variety of purposes.

It was concluded that whole Chlorella biomass was itself a useful ingredient for fish feed, and the existence of alternative sources made further processing into carotenoids a non-competitive. On the other hand, extraction and purification of phycobilins from Cyanobacteria has been described an patented.

Supercritical and near-critical extraction of Rosmarinus officinallis, Thymus zygis, Origanum virens and Thymus capitatus, was undertaken and the extracts characterised by identifying the major component fractions. Data obtained from extractions with carbon dioxide at various pressures and flow rates was used to develop and check models capable of predicting operational yields under scaleup conditions, and attempted operational cost estimations. In the special case of Coriandrum sativum, a fresh herb only capable of yielding its fragrance when cultivated in temperate to tropical climates and typical of Portuguese cooking, supercritical extraction from previously freeze-dried material was possible, but yielded a scent which was sensorially distinguishable from fresh, even when starting from the freeze dried material. In classical extraction, only a modified method of sample collection permitted the isolation of stable and characteristic extracts using classical hydrodistillation, with a special recovery technique.

Four monographs have been prepared, in each of which the most important data about each one of four main herbs, of Rosmarinus officinallis, Thymus zygis, Origanum virens and Thymus capitatus is detailed. Their extraction and volatile extract preparation are shown to have been optimised with respect to quality and quantity, under both classical and supercritical extraction schemes.

Information was sought on antioxidant extracts, as well as on essential oils. For this purpose the previously deodorised herbal material, after yielding an essential oil or a supercritical extract, was subject to solvent extraction, sometimes after an enzyme treatment to enhance its porosity.

Rosmarinus officinallis gave particularly strong antioxidant extracts in reasonable yield, while Myrtus communis also provided extracts of high antioxidant activity; in each case enzyme leaching was shown to be not necessary and even prejudicial.

For the extract of Thymus zygis, there was no clear positive response to its use as flavouring, and therefore no possibility of finding out more about ideal concentrations via sensory testing. For the second one, Coriandrum sativum, it was found that these - though they can only grow and produce odoriferous material under warm climates they need a substantial amount of water over a short life-span - can indeed yield a stable extract when using a classical but optimised methodology. Difficulty in separating the aromatic mixture from the water phase led us in this special case to explore the use of a relatively recent membrane technology pervaporation - which yielded extracts with good sensory attributes.

The extract is judged as very good by a sensory panel and it was possible to determine optimal concentration ranges. Evaluation of the blending of two distinct flavours, Allium and Coriandrum, in order to find optimal relative concentrations, did provide an optimal formulation. Nevertheless, and probably because a relatively cheap synthetic essence of Allium was used, the evaluation methodology showed that only the coriander flavour was instrumental in defining the optimum.

For Thymus capitatus, the essential oil was confirmed as an interesting high carcvacrol material with reasonable yield, and some members of the taste panel were extremely fond of it.

Attempts were also made to encapsulate the essential oils from these herbs into solid matrices, and experimentation on their liberation from these was performed using headspace chromatography. Results obtained were encouraging in as much as under particular sets of conditions the retention of these volatile essential oils was good, including a relatively slow release observed at cooking temperatures.