WO2019035786A2 - Ice tea enriched with nano-emulsified essential oils - Google Patents

Abstract

Ice Tea Enriched with Nano-emulsified Essential Oils The present invention is related to the production method of ice tea enriched with nano- emulsified essential oil, which comprises the process steps of brewing the white, black or green tea after adding water and then, mixing again after adding sugar and acidity regulator; obtaining nano-emulsified oil; adding the essential oil nanoemulsion obtained into the brewed tea into which sugar, water and acidity regulator has been added; then, keeping the mixture in ultrasonic ice bath or applying sonication to the mixture by means of ultrasonic probe; and immediately after storing at 4±2°C.

Description

Ice Tea Enriched with Nano-emulsified Essential Oils Technical Field

The present invention is related to ice tea enriched with essential oils of nano-emulsified cinnamon quill, ginger, clove bud, citrus, orange peel, lemon grass or mint, and the production method of said ice tea. State of Art

Ice tea is obtained by enriching green, white or black tea with fruit extracts such as lemon, apricot, peach, apple, pear and mango, vitamins, sweeteners, stabilizers and artificial aroma substances. Ice tea is a beverage that is commonly preferred by many people today. Therefore, it should not comprise substances that harm the human health.

However, it has been found out in the scientific studies made that the artificial additives used in the production of foods have some negative effects on health.

The essential oils made of aromatic plants used by humans in their daily nutrition and having protective effects such as antimicrobial and antioxidant activity, are volatile oils that are commonly used by food industry in the foods thanks to their special aromas and lower costs. The essential oils most of which are included in the list of GRAS (generally recognized as safe), and their compounds can be used as aroma additive in many foods, beverages and candy products and in addition to their said characteristics, the foods are preserved and their shelf lives are prolonged. However, the use of said compounds may be limited due to problems such as lack of compliance, volatility, sensitivity to oxygen, decrease in bioavailability due to light and temperature during storage and processing, and most importantly, lack of dissolving in many of the food environments (as they are hydrophobic compounds).

As a result of the abovementioned drawbacks and the inadequacy of the present solutions regarding the subject, an improvement is required in the related field of ice tea.

Objects of the Invention

The present invention is related to ice tea enriched with nano-emulsified essential oils, which meets the abovementioned requirements, eliminates all the disadvantages and offers some additional advantages. The primary object of the present invention is to obtain ice tea by cooling the brewed tea produced with hot water at 70°C from white, green or black tea in the rate of 1 .5%; preparing white, black or green brewed tea after adding water in the rate of 93.3%, sugar in the rate of 5% and acidity regulator in the rate of 0.2%; then, adding nano-emulsified essential oils obtained at 27°C via nanoemulsion technology into white, black or green brewed tea and storing at 4±2°C after packaging.

An object of the present invention is to enrich the ice tea in terms of antioxidant activity, aroma and taste thanks to the use of nano-emulsified essential oils.

An object of the present invention is to obtain white, black or green tea enriched with the essential oil chosen from the group of essential oils, which consists of nano-emulsified cinnamon quill, ginger, clove bud, citrus, orange peel, lemon grass and mint. Another object of the present invention is to use ultrasound guided emulsification method that is a high-energy emulsion obtaining method. Thus, a steady emulsion with more limited particle size or droplet size is formed.

Another object of the present invention is to use the essential oils of cinnamon quill, ginger, clove bud, citrus, orange peel, lemon grass or mint. The aromatic compounds, antioxidant and antimicrobial activities and functional properties of tea produced by using said essential oils are maintained during production, sale and storage. Therefore, a beverage that is more useful for human health and tastier compared to the beverages produced in the state of art is obtained.

A similar object of the present invention is to perform emulsification by using ultrasonic probe instead of ultrasonic bath when preparing nanoemulsion. The ultrasonic probes transfer the mechanical energy directly to the food sample or solution. In order to achieve the abovementioned objects, the present invention is a production method of ice tea enriched with nano-emulsified essential oils, characterized in comprising the following process steps; a) brewing the white, black or green tea after adding water and then, mixing again after adding sugar and acidity regulator,

b) obtaining nano-emulsified essential oil, c) adding the essential oil nanoemulsion obtained into the brewed tea into which sugar, water and acidity regulator has been added,

d) then, keeping the mixture in ultrasonic ice bath or applying sonication to the mixture by means of ultrasonic probe,

e) immediately after, storing at 4±2°C.

The structural and characteristic features and all the advantages of the present invention will be more clearly understood thanks to the detailed description given below and therefore, the evaluation needs to be made by taking said detailed description into consideration.

Detailed Description of the Invention

In this detailed description, the preferred embodiments of the ice tea enriched with nano- emulsified essential oils according to the present invention are described only for the subject to be understood better without any limiting effects.

The present invention is an ice tea obtained by cooling the brewed tea produced with hot water at 70°C from white, green or black tea in the rate of 1 .5%; preparing white, black or green brewed tea after adding water in the rate of 93.3%, sugar in the rate of 5% and acidity regulator in the rate of 0.2%; then, adding nano-emulsified essential oils obtained at 27°C via nanoemulsion technology into white, black or green brewed tea and storing at 4±2°C after packaging.

Nanoemulsion is a method used in order to increase the solubility of essential oils, achieve long-term steadiness thereof in food environment, control their release in liquid environment and prevent the changes that may face in food applications. Encapsulation of essential oils by means of nanoemulsion technology enables the product in which said nano-emulsified essential oils are used, to be enhanced in terms of antioxidant activity, aroma and taste.

In the preparation of nanoemulsions, ultrasound guided emulsification method that is a high- energy emulsion obtaining method, is used. In said method, emulsion formation is achieved by homogenizing the oil phase and aqueous phase in the presence of a surfactant that dissolves in water.

The content of tea composition according to the present invention

Raw Material Preferred Amount by Weight Available Amount by Weight

(%) (%) White, black or green 98 90-99

brewed tea

Essential oil of cinnamon 0,02 0,01 -0,1 quill, ginger, clove bud,

citrus, orange peel, lemon

grass or mint

Tween 20 (polyoxyethylene 0,04 0,02-0,2

sorbitan monolaureate)

Span 80 (sorbitan 0,04 0,02-0,2

monooleate)

Pure water 1 ,9 0,95-9,5

Characteristics of Raw Materials

White tea is a type of tea air dried in the shade or in the rooms the temperature levels of which are controlled, without withering, rolling and shaking on the contrary of black, green or oolong teas, which can only be harvested in spring for a few days. For white tea, the leaves of tea plant, which are immature and do not bloom completely, plucked. Said leaves are covered with white hairs and white tea is named after said hairs. It has been determined that some types of white tea have a strong antimutagenic activity and prevent oxidative DNA damage induced by excited solar radiation as photoprotective agents. Some of its benefits:

• decreasing the risks of liver, skin, colon, prostate, oesophageal, pancreas, gastric and ovarian cancer,

• reducing the risks of cardiac diseases,

• preventing oxidative stress by providing protection against the free radicals thanks to the antioxidants in white tea and thus, preventing the adverse effects thereof.

Black tea: It is a type of the that is produced from the same plant with green, oolong and white teas, however, gains the color black as it is subjected to a process different from said teas. During the production of black tea, tea leaves are oxidized more than the other types of tea obtained from the same plant. Therefore, taste of the brewed tea is more intense than the other teas. Benefits:

• helping to protect cardiovascular health,

• decreasing the risk of paralysis and heart attack,

• being rich in terms of antioxidants,

· preventing atherosclerosis, • decreasing the risk of kidney stones,

• providing mental alert,

• giving energy. Green tea: It is a tea obtained from the leaves of Camellia sinensis. The leaves are dried slowly for black tea that is obtained from the same plant; however, green tea is obtained by firing and drying after the leaves are picked. Some of its Benefits:

• providing mental alert and concentration,

• increasing muscle force, strength and performance during exercise thanks to caffeine therein,

• decreasing bad cholesterol while increasing good cholesterol

• controlling insulin resistance and blood glucose.

Ginger: Ginger (Zingiber officinale (L.) Rose) is a plant, biological activities of which have been studied intensively and antifungal [1 ], antiviral [2], anti-inflammatory and antioxidant [3] effects of which have been described well. Plant roots and extracts comprise polyphenol compounds having high level of antioxidant activity [4] such as 6-gingerol and derivatives thereof. Ginger is a prophylactic and therapeutic spices [7] that is globally used in the treatment of many digestive system diseases such as bloating, colic and diarrhea [5,6]. In addition, the gastrointestinal, cardiovascular, antihyperglycemic and anti-tumoral characteristics of ginger have also been reported [8,9,10,1 1 ]. Ginger essential oil is a volatile oil that has a color changing from pale yellow to pale amber and can be obtained with an efficiency of 1 .5% to 3% depending on the product quality [12]. This essential oil can be used several foods, beverages and medical products [13].

Cinnamon: Cinnamon belonging to Lauraceae family, is an aromatic scented tree that has nearly 250 species {Cinnamomum zeylanicum, C. pauciflorum, C. burmannii and C. tamala etc.) [14] and is evergreen. It has been used as a drug especially in India and China [16] since the old times for treating the diseases such as dyspepsia, gastritis, blood flow troubles and inflammation [15]. It is known that it has antiallergic, antiulcerogenic, pain relieving and anesthetic effects. In vitro studies have shown that cinnamon mimics the function of insulin in isolated adipositis [17]. In addition to applications of cinnamon in medicine, it is among the most ancient spices used thanks to its strong aromatic, warm and sweet scent [18]. Cinnamon quill essential oil is a viscous liquid with pale yellow color and is made of the peels of cinnamon tree or other Cinnamomum species naturally. 90% of cinnamon quill essential oil consists of organic compound known as cinnamaldehyde and said compound provides the essential oil with typical cinnamon taste and smell. As a sweetener, cinnamaldehyde is commonly added to gums, ice creams, candies and beverages at the level of 9-4900 ppm (less than 0.5%) [19].

Clove: Clove bud essential oil extracted from the buds of clove (Eugenia caryophyllata Thunb.) plant, has characteristics such as antibacterial, antifungal, insecticidal and antioxidative activities and are generally used in the foods thanks to its sweetening and antimicrobial characteristics [20,21 ,22]. Its strong biological activity and antimicrobial effect arises from high amount of eugenol included therein [23]. Moreover, clove oils have many therapeutic characteristics such as anti-inflammatory, nausea preventing, pain killing, relaxing and antiseptic effects [24,25].

Citrus: Citrus essential oils are generally used by being transformed into concentrate via vacuum fractional distillation [26] and they comprise d-limonene more than 80% even if some of monoterpenes are removed during the process in accordance with the degree of concentration [27]. The commercially known name of d-limonene and other monoterpenes is "terpene". In the market, there are concentrates of tangerine, lemon, grapefruit and orange oils having different concentration degrees. The oxidation tendency of concentrate oils is lower, while water solubility thereof is higher and sensory characteristics are better [28,29]. It has been determined that thanks to concentration process, organoleptic sesquiterpenes (notkaton, valensen, mirsen) and oxygenators (decanal, octanal, citral) have increased [30]. As these citrus compounds are sensitive to heat and oxidation, heat transfer performed during the process to minimize the undesired smell and taste arising from thermal stress and thereby, partial spoilage in the oils, must be available [31 ].

Orange peel: Orange peel essential oil is among the most important volatile oils used in food, cosmetic and drug industries. The reason of popularity of the orange peel essential peel is that it has both enjoyable aromatic smell and healing (therapeutic) characteristics [32]. Generally, it comprises 94% limonene, 2% myricin, 0.5% linalol, 0.4% octanal, 0.4% decanal, 0.1 % neral, 0.1 % geraniol and etc. [33]. Thanks to high levels of aldeydes (octanal, decanal), alcohol (linalol) and terpene (limonene), which have low molecular weight, within orange peel essential oil [34], it is highly volatile [35]. Additionally, as most of said compounds have high levels of lipophilic features, they have lower solubility because of less hydrogen bond formation in the beverages comprising water and sugar [33]. Lemon grass: Belonging to poaceae family, this plant is known as Citronella in the world. It is named as lemon grass because the leaves of the tree on which it grows, smell like lemons. Some of its Benefits:

• cleaning respiratory tract and suppressing cough,

· having pain killing, expectorant, anti-inflammatory and antispasmodic effects,

• having appetizing effects and relieving stomach as it has peptic features,

• decreasing blood glucose level for diabetic patients,

• being good for prostate patients,

• being fever reducer.

Mint: Mint essential oil isolated from mint leaves (Mentha piperita L.) has economic importance and is commonly used in food, cosmetic, candy and drug industries [36, 37]. As of chemical composition, it generally comprises the compounds of 1 .76% d-limonene, 2.91 % cineol, 0.71 % terpeniol, 14.51 % menthone, 9.26% neomenthol, 30.69% menthol, 2.31 % pulegone, 12.86% menthyl acetate, 2.52% caryophilenne and 0.54% β-farnesene [38].

Surfactant: It is a chemical compound that affects surface tension when dissolved in water or an aqueous solution. In the composition according to the present invention, tween 20 and span 80 are used as surfactant. Said substances chosen as surfactant, are nonionic surfactants that do not have irritating characteristic and are assumed to be in the list of GRAS. The formation and stability of nanoemulsions consisting of nonionic surfactants are not affected from pH or ionic resistance. An important criterion for choosing surfactant is hydrophilic lipophilic balance (HLB) and HLB is required to be between 8 and 18 in order to form submicron oil/water emulsions. The balanced use of surfactants having low and high HLB values is important in the formation of stable emulsion formation (HLB values of Tween 20 and Span 80 are 16,7 and 4.3, respectively).

The production method of ice tea according to the present invention:

1) Brewing the white, black or green tea after adding water and then, mixing again after adding sugar and acidity regulator,

• grinding the white, black or green tea in the rate of 0.8% to 1 .5% by means of a grinder and sieving by means of 80 mesh stainless steel,

• adding the sieved tea, 15gL^~1 (15 g/L) powder, into hot distilled water at 70- 80°C and mixing constantly for approximately 7-10 minutes,

• subjecting the mixture to filtration process, • then, adding 4.1 -5.2% sugar, 0.1 -0.3% acidity regulator and 93-95% water therein,

• mixing the mixture at 300 rpm for 5 minutes. The content of brewed tea;

After said mixture is obtained, 90-99% of said mixture (brewed tea) is taken in order to prepare ice tea. 2) Obtaining nano-emulsified essential oil,

Tween 20 and Span 80, which do not have irritating characteristic and are assumed to be in the list of GRAS, are used as surfactants in the production of nanoemulsion. Ultrasound guided emulsification method that is a high-energy emulsification method is performed. In said method, essential oil (1 % w/w) and span 80 (2%) forms the oil phase, while aqueous phase consists of deionized water (95% w/w) and tween 20 (2% w/w) (oil and aqueous phases will be adjusted so as to be 100 g in total) (1 % essential oil, 2% Span 80 and 2% Tween 20).

• Mixing the essential oil that will be used, with span 80 (sorbitan monooleate) at 25-27°C and 700 rpm fixed mixing speed, until a clear emulsion is obtained, · Mixing the ultra-deionized water with tween 20 (polyoxyethylene sorbitan monolaureate) at 27°C and 700 rpm fixed mixing speed, until a clear emulsion is obtained,

• Dripping aqueous phase into the oil phase that is being stirred at 700 rpm, and mixing thereof for approximately 30 minutes,

· Homogenizing the mixture obtained in an ice bat at 8000-9000 rpm for approximately 30-40 minutes.

Essential oil used in said invention is cinnamon quill, ginger, clove bud, citrus, orange peel, lemon grass or mint. 3) Adding the essential oil nanoemulsion obtained into the brewed tea into which sugar, water and acidity regulator has been added,

Said essential oil nanoemulsion is added into the brewed tea into which sugar, water and acidity regulator has been added, in the rate of 1 -10%. In nanoemulsion, the rates of brewed tea are 2:198, 4:196, 6:194, 8:192, 10:190, 15:185 and 20:180, and represent the amounts of nanoemulsion in the rates of 1 , 2, 3, 4, 5, 7.5 and 10%, which are added into brewed tea.

4) Then, keeping said mixture in ultrasonic ice bath or applying sonication by means of ultrasonic probe.

In order for said mixture to form nanoemulsions, two different methods are performed. In the first method, ultrasonic ice bath is applied. In said method, said mixture is kept in ultrasonic ice bath at 200 W for 30-40 minutes and then nanoemulsions are formed.

In the second method, however, probe is placed within jacketed glass cylindrical cell so as to be 1 cm below the emulsion surface and sonication (UP400S ultrasonic processor Hielscher, Germany) is performed. Sonication is performed in different amplitudes ranging from 70% to 100% and in different processing periods ranging from 90 hours to 150 hours (three different amplitude values (70, 80 and 100%) x three different sonication periods (90, 120 and 150 hours). In order for product temperature to be fixed at 5-45°C ±1 °C, anti-freezing liquid will be passed through the glass double-jacketed cylindrical cell. Thanks to constant circulation of anti-freezing liquid within the system, it has been reported that the temperature is fixed at (5-45) ±1 °C that is the targeted temperature, during sonication.

5) Then, packaging and storing at 4±2°C.

Points to consider in the present invention;

• maintaining in cool environment and keeping away from sunlight,

• shaking before drinking because precipitation may occur naturally. REFERENCES

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Claims

1. A production method of an ice tea enriched with nano-emulsified essential oils, characterized in comprising the following process steps; a) brewing the white, black or green tea after adding water and then, mixing again after adding sugar and acidity regulator,

b) obtaining nano-emulsified essential oil,

c) adding the essential oil nanoemulsion obtained into the brewed tea into which sugar, water and acidity regulator has been added,

d) then, keeping the mixture in ultrasonic ice bath or applying sonication to the mixture by means of ultrasonic probe,

e) immediately after, storing at 4±2°C.

2. Production method according to Claim 1 , characterized in that the white, black or green tea used for preparing the brewed tea mentioned in process step a, comprises the following process steps;

• grinding,

· sieving afterwards,

• adding water at 70-80°C into the sieved tea and mixing,

• subjecting the mixture to filtration process.

3. Production method according to Claim 1 , characterized in that the white, black or green tea mentioned in process step a is in the rate of 0.8-1 .5%, sugar is in the rate of 4.1 -5.2%, acidity regulator is in the rate of 0.1 -0.3%, and water is in the rate of 93-95%.

4. Production method according to Claim 1 , characterized in that the mixing process mentioned in process step a is performed at 300 rpm for 5 minutes.

5. Production method according to Claim 1 , characterized in that the essential oil mentioned in process step b is cinnamon quill, ginger, clove bud, citrus, orange peel, lemon grass or mint.

6. Production method according to Claim 1 , characterized in that the nano-emulsified essential oil mentioned in step b is obtained in the following process steps; mixing the essential oil that will be used, with sorbitan monooleate at 25-27°C and 700 rpm fixed mixing speed, until a clear emulsion is obtained,

mixing the ultra-deionized water with polyoxyethylene sorbitan monolaureate at 27°C and 700 rpm fixed mixing speed, until a clear emulsion is obtained, Dripping aqueous phase into the oil phase that is being stirred at 700 rpm, and mixing thereof for approximately 30 minutes,

homogenizing the mixture obtained in an ice bat at 8000-9000 rpm for approximately 30-40 minutes.

7. Production method according to Claim 1 , characterized in that the essential oil nanoemulsion mentioned in step b is added into the brewed tea in the rate of 1 -10%.

8. Production method according to Claim 1 , characterized in that the mixture mentioned in process step c is kept in ultrasonic ice bath mentioned in process step d, at 200 W for 30-40 minutes.

9. Production method according to Claim 1 , characterized in that sonication process mentioned in process step d is performed by placing a probe within jacketed cylindrical glass cell so as to be 1 cm below the emulsion surface.

10. Ice tea enriched with nano-emulsified essential oils, which is obtained by the method according to Claim 1 .