Food or edible material: processes – compositions – and products – Products per se – or processes of preparing or treating... – Beverage or beverage concentrate
Reexamination Certificate
2000-05-02
2001-10-09
Weier, Anthony J. (Department: 1761)
Food or edible material: processes, compositions, and products
Products per se, or processes of preparing or treating...
Beverage or beverage concentrate
C426S049000, C426S465000
Reexamination Certificate
active
06299926
ABSTRACT:
The invention relates to a method for obtaining improved quality of black tea. The invention particularly relates to a process of treating tea leaves post plucking with senescence modulators like jasmonic acid and its derivatives to enhance the aroma of black tea.
BACKGROUND AND PRIOR ART
Black leaf tea is traditionally produced by oxidising and drying freshly plucked green tea leaves. The method of preparing such teas is well known to those skilled in the art. Generally, to prepare black leaf tea, fresh green leaves of the plant
Camellia sinensis
are withered (subjected to mild drying), comminuted or macerated, fermented (in which process enzymes in the tea leaf use atmospheric oxygen to oxidise various substrates to produce brown-coloured products) and then fired (to dry the tea leaves).
The withering process, which is sometimes omitted, allows certain chemical and biochemical changes to occur and also the moisture content of the leaves is brought down from 90% to 50-70%. Biochemical/chemical changes taking place during withering, increase the yield of the volatile flavour compounds in tea.
The disruption of the cellular integrity of leaf during the maceration step allows oxidation of catechins by enzymes such as polyphenol oxidase that results in the development of colour and aroma molecules.
Phenylacetaldehyde and benzaldehyde are the major aroma components and are formed during the fermentation stage. During the process of fermentation, the quinones formed from catechins by the action of enzyme polyphenol oxidases/peroxidases convert phenylalanine into phenyl acetaldehyde. Phenyl acetaldehyde imparts a floral aroma whereas benzaldehyde has a sweet almond like aroma. Apart from phenylacetaldehyde and benzaldehyde, the terpenoids are also important in imparting floral aroma to tea.
Jasmonic acid and its derivatives such as methyl jasmonate and dihydro jasmonate are known to induce senescence in plants and also mimic wound signal. However, it has now been found that treating tea leaves post plucking with these chemicals significantly enhances the aroma of tea.
STATEMENT OF THE INVENTION
The present can be said in broad terms to relate to process for manufacturing black leaf tea comprising the steps of treating freshly plucked tea leaves with jasmonic acid or one of more derivatives thereof, macerating and fermenting the leaves, firing the fermented leaves to arrest fermentation and then drying them to yield black leaf tea. Treating the leaves in this way enhances the aroma of the black tea and tea beverages made form the black tea.
Preferred derivatives of jasmonic acid include methyl jasmonate and methyl dihydro jasmonate.
The leaves are preferably with jasmonic acid or one of more derivatives thereof at a concentration of 0.0001 to 0.5% for 10 minutes to 24 hours at a temperature of 10 to 45° C. The substances can be applied singly (i.e. in one dose) or in split doses.
The invention can also be said to be a process of manufacturing black tea comprising treating tea leaves post plucking with jasmonic acid or its derivatives or a mixture thereof at a concentration of 0.001 to 0.5% for 14 to 20 hours at a temperature 15 to 30° C. to improve the aroma of tea.
“Tea” for the purposes of the present invention means leaf material from
Camellia sinensis
var.
sinensis
or
Camellia sinensis
var.
assamica.
It also includes rooibos tea obtained from
Aspalathus linearis
however that is a poor source of endogenous fermenting enzymes. “Tea” is also intended to include the product of blending two or more of any of these teas.
For the avoidance of doubt the word “comprising” is intended to mean including but not necessarily “consisting of” or “composed of”. In other words the listed steps or options need not be exhaustive.
Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or concentrations of material ought to be understood as modified by the word “about”.
DETAILED DESCRIPTION OF THE INVENTION
The present invention concerns a modification to the well known process for manufacturing black tea. The modification involves treating the tea leaves with jasmonic acid or its derivatives or a mixture thereof in order to enhance the aroma of the black tea and tea beverages made form the black tea.
The aroma enhancing compounds are applied post plucking, preferably prior to an optional but preferable withering step. The compounds are preferably in the form of a solution at a concentration of 0.0001-0.5%. The application of the aroma enhancing compounds is either singly or in split doses. The treatment is preferably given in the form of a spray or dip.
The aroma enhancing compounds are preferably jasmonic acid or one or more derivatives such as methyl jasmonate and dihydro jasmonate, or mixtures thereof.
The concentration of the compounds is in the range 0.0001 to 0.5% on made tea basis but preferably in the range of 0.001 to 0.2%.
The duration of the treatment is preferably 10 minutes to 24 hours but especially 14 to 20 hours.
The temperature during the treatment is preferably maintained at 10-45° C. but especially 15 to 30° C.
After treatment with the aroma enhancing compounds, the shoots are withered following the normal procedure.
After withering the tea is further processed according to conventional procedures, i.e. given four CTC cuts, fermented and fired.
REFERENCES:
patent: 3709694 (1973-01-01), Killinger et al.
patent: 3966986 (1976-06-01), Hunter et al.
patent: 4297380 (1981-10-01), Horman et al.
patent: 4880649 (1989-11-01), Holzner et al.
patent: 5094860 (1992-03-01), Newhall et al.
patent: 30 06 092 A1 (1981-10-01), None
patent: 2 074 838 A (1981-11-01), None
patent: 63 129952 (1988-06-01), None
Dhanaraj et al, Journal of the Science of Food and Agriculture, 37(2):185-193 (1986).
Krefting et al, Tea and Coffee Trade Journal, 148(5):25-26 (1976).
Bauer, “Common fragrance and flavor materials”, 1985 (XP002123890).
Kobayashi et al, FSTA Abstract AN 89(07):H0069. Published 1989.
Balakrishnan Padma
Rao Anitha
Sharma Navin K.
Pillsbury & Winthrop LLP
Unilever Patent Holdings B.V.
Weier Anthony J.
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