Biocatalysis in the production of Essential Oils
(Composition of essential oils, application, features of raw materials, production of rose oil (using b-glucosidase), the mode of the enzymatic process, features of the technology )
2. ESSENTIAL OILS
ESSENTIAL OIL is a concentrated hydrophobic liquid containing
volatile (easily evaporated at normal temperatures) chemical
compounds from plants. Essential oils are also known as volatile
oils, ethereal oils, aethereal, or simply as the oil of the plant from
which they were extracted, such as oil of clove. An essential oil is
"essential" in the sense that it contains the "essence of" the plant's
fragrance—the characteristic fragrance of the plant from which it is
derived. The term "essential" used here does not mean
indispensable or usable by the human body, as with the terms
essential amino acid or essential fatty acid, which are so called
because they are nutritionally required by a given living organism.
3. Essential oils are generally extracted by distillation, often by using
steam. Other processes include expression, solvent extraction,
sfumatura, absolute oil extraction, resin tapping, wax embedding,
and cold pressing. They are used in perfumes, cosmetics, soaps and
other products, for flavoring food and drink, and for adding scents
to incense and household cleaning products.
4. COMPOSITION OF ESSENTIAL OILS
Essential oils are complex aromatic substances derived from plants that are mainly composed
of terpenes and other compounds, namely aldehydes, fatty acids, phenols, ketones, esters,
alcohols, nitrogen and Sulphur compounds.
5. APPLICATION ESSENTIAL OILS
IN FOOD
Essential oils are a good source of several bioactive compounds, which possess antioxidative
and antimicrobial properties, so their use can be very useful to extend shelf-life in food
products.
Antibacterial Activity
essential oils characterized by a high level of phenolic compounds, such as carvacrol, eugenol,
and thymol, have important antibacterial activities.
These compounds are responsible for the disruption of the cytoplasmic membrane, the
driving force of protons, electron flow, active transport, and also coagulation of cell contents.
Antioxidant Activity
Numerous studies have demonstrated the antioxidant properties of essential oils.
6. APPLICATION ESSENTIAL OILS
Anti-Inflammatory Activity
Cancer Chemoprotective Activity
The varied therapeutic potential of essential oils attracted, in recent years, the attention of researchers
for their potential activity against cancer.
Repellent and Insecticidal Activity
Research has shown that essential oils have potential as a natural pesticide. In case studies, certain oils
have been shown to have a variety of deterring effects on pests, specifically insects and select
arthropods. These effects may include repelling, inhibiting digestion, stunting growth, decreasing rate of
reproduction, or death of pests that consume the oil. However, the molecules within the oils that cause
these effects are normally non-toxic for mammals. These specific actions of the molecules allow for
widespread use of these green pesticides without harmful effects to anything other than pests.Essential
oils that have been investigated include rose, lemon grass, lavender, thyme, peppermint, and
eucalyptus.
8. Features of raw materials
All parts of aromatic plants may contain essential oils as follows:
Flowers including orange, pink, lavender, and the (clove) flower bud or (ylang-ylang) bracts.
Leaves including eucalyptus, mint, thyme, bay leaf, savory, sage, pine needles, and tree
underground organs, e.g.
roots (vetiver).
Rhizomes (ginger, sweet flag).
Seeds (carvi, coriander).
Fruits including fennel, anise, Citrus epicarps.
9. Wood and bark including cinnamon, sandalwood, rosewood.
Volatile Synthesis by Cultured Microorganisms:
most of the recent effort is directed to using microorganisms.
Volatile aldehydes and alcohols are far more easily produced by cultured
microorganisms, and efforts to genetically alter microbes for producing or
biotransforming terpenoids or phenolics were met with rewarding success.
Therefore, in most cases microorganisms are used for their production, instead of
plant cell cultures. Also, microorganisms (bacteria, algae and fungi, including yeasts)
are sturdier than plant cells under bioreactor conditions.
Features of raw materials
11. Rose oil
The fragrance of rose is sweet and honey like and is appreciated
by many people.
The principal flavor compounds of rose oil were analyzed, and
found to include citronellol, geraniol, phenylethanol, linalool,
nerol, farnesol, rose oxide, eugenol and methyleugenol.
Rose oil is one of the most important flower oils; the aroma of
rose is mostly widely applied in rose tea, wine, sweetmeat, cake
and top-grade cosmetics, so the application is not limited. Rose
oil adds mellowness It was reported that rose aroma components
mostly exist in a dissociative state, but some are combined with
other components with glucosidic linkages. When the glucoside
was completely hydrolyzed, the glucosidic linkage was fractured
and this produced sugar and glucoside. The released glucosides
may be potential aroma components.
12. Extraction Of Rose Oil Enhanced
By Β-glucosidase
It was reported that rose aroma components mostly exist in a dissociative state, but some are
combined with other components with glucosidic linkages. When the glucoside was
completely hydrolyzed, the glucosidic linkage was fractured and this produced sugar and
glucoside. The released glucosides may be potential aroma components. It was also reported
that the natural glucoside in roses was D-glucoside, and almost all of the natural glucosides
were β-glucoside, so β-glucosidase (EC3.2.1.4) was investigated as a flavor enzyme.3
Therefore, β-glucosidase could be applied in extraction to enhance the release of aroma
compounds, which could theoretically greatly increase output. a mutant with higher activity of
β-glucosidase was obtained, and this β-glucosidase could tolerate heat and preferred acid
conditions. Therefore, β-glucosidase was applied in the experimental extraction of rose oil to
increase output and to reduce cost, which would have social and economic benefits
commercially.
13. It was found that β-glucosidase could not only increase the output of rose oil, but
also could enhance the perceived quality of the aroma. The aroma of the sample
with enzyme hydrolysis was much stronger, which was validated by sensory
evaluation. There were differences in components after enzyme hydrolysis; most
components increased, some new components emerged, but some components
decreased or even disappeared many flavor precursors existing in rose flower
that could be released by βglucosidase. Therefore, the yield of rose oil could be
greatly increased, which showed the considerable potential of applying β-
glucosidase in the commercial extraction of rose oil.
Sensory evaluation:
the hydrolysis sample with enzyme hydrolysis smell stronger, which show that
the aroma enhancement effect of β-glucosidase evident.
Extraction Of Rose Oil Enhanced
By Β-glucosidase:
14. Raw material sources
Dry roses local
β-Glucosidase was prepared in laboratory (the activity of β-glucosidase was
221.36 IU/g).
Enhancement of aroma using β-glucosidase
crush rose and suspend in buffer solution (pH 4.5, 0.2 M Na2HPO4, 0.1 M
citric acid), then stir with β-glucosidase at the desired temperature for the
specified time, extract from the vapor headspace.
16. Dry roses were removed peduncle, then crushed before adding the enzyme.
After enzyme hydrolysis, rose oil was extracted with vapor .
17. The conditions of β-glucosidase hydrolysis
From the experiments, it was clear that βglucosidase could increase the output
of rose oil and different conditions of hydrolysis resulted in a different output.
Therefore, it necessary to optimize the hydrolysis parameters.
18. Enzyme amount:
The amount of beta-glycosidase enzyme should be 10% of the amount of powdered dry rose.
Stirring rate:
The Stirring rate optimal at 150 rpm, then dropped with the increase or decrease in stirring rate .
The rose oil may volatilize or release with higher stirring rate, but with the lower stirring rate, the
reaction incomplete because of the incomplete contact. Therefore, the best stirring rate for
complete contact of flower and enzyme 150 rpm.
Temperature of enzymatic reaction:
Therefore, the temperature of enzymatic reaction of 40°C the best.
The effect of extraction time on rose oil output After the optimal hydrolysis conditions were
obtained, an extraction time of 90 min was the best.
The conditions of β-glucosidase hydrolysis