Enzymes in Food and Beverage Processing

2 Use of Enzymes in the Manufacture of Black Tea and

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Instant Tea GARY W. SANDERSON and PHILIP COGGON Thomas J. Lipton, Inc., 800 Sylvan Ave., Englewood Cliffs, N.J. 07632

Black tea is manufactured from the rapidly growing shoot tips of the tea plant (Camellia sinensis, (L), O. Kuntze). These shoot tips are collectively known as the tea flush, and they are comprised of immature plant parts, namely, the terminal bud, the f i r s t 2 or 3 leaves, and the included stem piece. They also contain both the enzymes and the substrates that will react during the black tea manufacturing process. The enzymically catalyzed reactions involving tea flush constituents are essential to the preparation of black tea: These reactions are described further in the following discussion. The black tea manufacturing process i t s e l f begins as soon as the tea flush is plucked (harvested), and it is carried out on, or very near, the plantation where the tea flush is grown. The entire process, from plucking to finished black tea product, requires about 8 to 24 hours. The process is outlined in Table 1, and more details can be found in reviews by Harler ( 1 ) , Eden (2), Hainsworth (3), and Sanderson ( 4 ) . The enzymes known to be involved in black tea manufacture are listed in Table 2 (part A) and they are discussed in the text below. Instant tea may be prepared from either black tea or directly from fresh green tea flush. Processes for the manufacture of instant tea have been summarized by Pintauro ( 5 ) , and by Sanderson ( 6 ) . A few enzymic processes for use in manufacturing i n stant tea have been described in the patent literature. The enzymes involved are listed in Table 2 (part B) and their role in instant tea manufacture is discussed in the following text. Enzymes Involved in Black Tea Manufacture (Table 2 , Part A) Tea Catechol Oxidase. This enzyme is certainly the most important single enzyme in black tea manufacture. As soon as the withered tea flush is macerated (Table 1 ) , an enzymic oxidation of the tea flavanols (I-IV) is i n i t i a t e d . Tea catechol oxidase is the catalyst for this oxidation and the process is called "tea fermentation".

12 In Enzymes in Food and Beverage Processing; Ory, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

2.

SANDERSON A N D COGGON

Table 1 :

13

O u t l i n e of Black Tea Manufacturing Process.

Steps of Process


Manufacture of Black Tea and Instant Tea

Comments

1.

Growth of tea leaves

Tea plants (Camellia s i n e n s i s , [ L . ] 0. Kuntze) are c u l t i v a t e d to encourage the rapid growth of shoot t i p s c o l l e c t i v e l y c a l l e d the f l u s h .

2.

Harvest of tea leaves ( i . e . plucking)

The f l u s h i s picked once every 2 to 4 weeks during the growing season.

3.

Withering

The plucked f l u s h i s caused p a r t i a l l y to d e s s i c a t e from about 80% moisture down to about 65% moisture in 4 to 18 hours.

4.

Macerating

The withered tea f l u s h i s macerated to cause the endogenous enzymes and tea f l a v a n o l s to come i n t o c o n t a c t .

5.

Fermenting

The macerated tea f l u s h i s allowed to stand f o r 1 to 4 hours while i t oxidizes ( F i g . 1).

6.

Firing

The fermented tea f l u s h i s d r i e d to about 2% moisture in about 20 minutes using hot a i r a t 70° to 95°C.

7.

Sorting

The f i r e d black tea i s s i f t e d i n t o grades according to s i z e of tea particles.

8.

Storing/Shipping

F i r e d black tea may be consumed immediately but i t u s u a l l y takes 2 to 4 months f o r i t to t r a v e l from point of o r i g i n to point of consumption.

9.

Conversion to i n s t a n t tea

Most i n s t a n t tea i s prepared from black tea i n the country i n which i t w i l l be s o l d .

In Enzymes in Food and Beverage Processing; Ory, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977.

14

ENZYMES

Table 2:

IN FOOD AND BEVERAGE

Enzymes with Known Functions in Tea Manufacture.

Name of Enzyme


A.

PROCESSING

Function

BLACK TEA MANUFACTURE (These enzymes are endogenous to f r e s h green tea leaves) Oxidase

Oxidation of tea f l a v a n o l s r e s u l t i n g i n formation o f tea pigments ( F i g . 1) and i n d i r e c t l y i n formation of black tea aroma ( F i g . 2 ) .

1.

Catechol

2.

Peroxidase

Removes any peroxide formed during tea fermentation ( F i g . . 1 ) . Can cause oxidat i o n of tea f l a v a n o l s i f hydrogen peroxide i s added.

3.

Tea M e t a l l o p r o t e i n

Causes o x i d a t i o n of unsaturated f a t t y a c i d s , leading to formation of black tea aroma c o n s t i t u e n t s .

4.

Pectin Methyl Esterase

Demethoxylates tea pectins r e s u l t i n g in formation o f hard, glossy covering on black tea p a r t i c l e s when well made.

5.

Alcohol ase

Supposed to play a r o l e in the formation of some of the a l c o h o l s i n black tea aroma by causing reduction of the c o r responding c a r b o n y l s .

6.

Transaminase

Supposed to play a r o l e i n the b i o s y n t h e t i c transformation of amino acids to compounds t h a t are important i n black tea aroma.

7.

Peptidase

Acts to form amino acids from l e a f prot e i n s e s p e c i a l l y during w i t h e r i n g (Table 1): Amino acids are one type of black tea aroma precursor ( F i g . 2 ) .

8.

Phenylalanine Ammonia Lyase

Involved in the biosynthesis of tea flavanols.

9.

5-Dehydroshikimate Dehydrogenase

Involved i n the biosynthesis of tea flavanols.

Dehydrogen-

(Table 2, part B, continued next page)



Table 2:

Enzymes with Known Functions in Tea Manufacture,(cont.)

Name o f Enzyme


B.


Function

INSTANT TEA MANUFACTURE (These enzymes are from non-tea sources. They have been added to tea preparations f o r s p e c i f i c purposes). Catalyzes h y d r o l y s i s of g a l l o y l groups from tea polyphenolic compounds to produce c o l d water s o l u b l e tea s o l i d s .

1.

Tannase

2.

Polyphenol

3.

Peroxidase

Causes "tea fermentation" when H2O2 i s added.

4.

Pectinase

Causes breakdown o f water extracted tea pectins to reduce foam forming tendency of i n s t a n t tea powders.

5.

Cellulase

Breaks down c e l l wall material in tea l e a f to increase y i e l d o f i n s t a n t tea solids.

Oxidase

Causes "tea fermentation" (same as A J . above).


15


16

ENZYMES


PROCESSING

Tea catechol oxidase i s an endogenous component of tea f l u s h (7^9), and i t appears to be s o l u b l e i n the cytoplasm of i n t a c t f r e s h green tea leaves (10, 11). The enzyme does not r e a c t with the tea f l a v a n o l s ( I - I V ) , which are present i n the c e l l v a c u o l e s , u n t i l the tea l e a f t i s s u e s are d i s r u p t e d causing the c e l l contents to be mixed. The "Maceration" step o f the Black Tea Manufacturing Process (Table 1) brings about mixing of the tea f l u s h c e l l contents thereby i n i t i a t i n g "Tea Fermentation". The primary r e a c t i o n o c c u r r i n g during tea fermentation i s the o x i d a t i o n o f the tea f l a v a n o l s to t h e i r r e a c t i v e o x i d i z e d intermediates (V-VIII) which then form the black tea pigments (IX-XVI): These r e a c t i o n s are o u t l i n e d i n Figure 1. These same o x i d i z e d tea f l a v a n o l s (VVIII) a l s o act as o x i d i z i n g agents to cause the o x i d a t i v e degradation of other tea f l u s h c o n s t i t u e n t s (Figure 2 ) : Reactions of t h i s type are important in the formation of black tea aroma. The biochemistry of tea fermentation i s discussed f u r t h e r i n reviews by Sanderson (4, 12), Sanderson and Graham (13) and Reymond (14). Tea catecFol oxidase i s probably s o l u b l e i n the i n t a c t tea l e a f ( 1 0 , 1 1 , 1 5 , 1 6 ) , but i t i s r e a d i l y i n s o l u b i l i z e d by i n t e r a c t i o n with the tea f l a v a n o l s (17). The r e s u l t i s t h a t tea c a t e chol oxidase i s immobilized w i t h i n the i n s o l u b l e p o r t i o n o f the tea f l u s h during the maceration step of black tea manufacture. One of the s e c r e t s of black tea manufacture i s to obtain c o n d i t i o n s that w i l l bring the tea f l a v a n o l s to the a c t i v e s i t e of the enzymes s i n c e the reverse cannot take p l a c e . In f a c t , w i t h e r i n g , the step o f black tea manufacturing j u s t preceeding maceration, i s c r i t i c a l i n t h a t i t must be c a r r i e d f a r enough to destroy the semipermeable nature of the c e l l membranes and y e t not so f a r as to render the f l u s h so dry t h a t the tea f l a v a n o l s are no longer in s o l u t i o n . F u r t h e r , maceration of the tea f l u s h must be of the kind that w i l l cause mixing of the c e l l contents without reducing the t i s s u e s to a pulp thereby preventing the f r e e entry of oxygen i n t o the "fermenting" macerated tea f l u s h . The l e v e l s of a c t i v i t y of tea catechol oxidase in tea f l u s h appear to vary during the growing season (18-20) and during the black tea manufacturing process (15, 17). "The cause of these changes i s not known but they musT~be~Tmportant s i n c e the enzyme i s e s s e n t i a l to the black tea manufacturing p r o c e s s . C r e d i t f o r e l u c i d a t i o n of the true nature of the tea c a t e chol oxidase enzyme goes to Sreerangachar (21-24). The work, and the c o n t r o v e r s y , that l e d to the i d e n t i f i c a t i o n and charact e r i z a t i o n of tea catechol oxidase i s a most important p a r t o f the h i s t o r y of tea chemistry but one should c o n s u l t Roberts ( 2 5 ) , or Sanderson ( £ ) , f o r more d e t a i l s on t h i s s u b j e c t . The enzyme i s known to contain copper (24). The enzyme has a remarkable s p e c i f i c i t y f o r the ortho-diHydroxy group on the B-ring of the tea f l a v a n o l s ( I - I V ) : Besides the tea f l a v a n o l s , catechol (XVII) and p y r o g a l l o l (XVIII) w i l l serve as substrates f o r t h i s enzyme but g a l l i c a c i d (XIX) and chlorogenic a c i d (XX) do not (26). F i n a l l y , tea catechol oxidase i s s u s c e p t i b l e to p r e c i p i t a t i o n by



2.



(Structures

17

Unknown)

Figure 1. Oxidation pathway for teaflavanohduring fermentation. The tea flavanols (I: R = R' = H; II: R = H, R' = galloyl; III: R = OH, R' = H; and IV: R = OH, R' = galloyl) are enzymically oxidized to their respective intermediates (V-VIII) which undergo the following condensation reactions: (A) I or II plus III or IV —» IX—XII; (B) I or II plus gallic acid (XIX) -> XIII or XIV; (Cj I, II, III, or IV XV (by 4,8 linkages); and (D)I, II, III, or IV XVI (by unknown linkages).


In Enzymes in Food and Beverage Processing; Ory, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1977. fresh tea leaf)

(already present in

(dependent on tea fermentation and firing)

(dependent on tea fermentation only)

MANUFACTURING PROCESS

Black tea aroma constituents and precursors of black tea aroma constituents

flavanols (transitory)

Oxidized tea

Black

BLACK TEA

Black tea aroma constituents

pigments

tea

Figure 2. Proposed scheme for formation of bhck tea aroma. Materials present in fresh (or withered) tea flush are enclosed in tangles. Materials present in dashed enclosures are largely transitory in that they are undergoing change during the black tea man facturing process. Materials present in brackets are those present in the finished black tea product. The amount of any of the ab materials present in the bhck tea produced would be dependent on the conditions of manufacture.

FRESH TEA LEAF

constituents

Volatile aroma

Other precursors

Aroma precursors Amino acids Carotenes Lipids

Tea Flavanols

oxidase

Tea Catechol


2.


Manufacture of Bhck Tea and Instant Tea

11


the tea f l a v a n o l s ( 2 7 ) , but the a c t i v i t y of t h i s enzyme only decreases slowly when"~the enzyme i s exposed to tea f l a v a n o l s . It i s c l e a r that the tea catechol oxidase enzyme i s well s u i t e d to c a t a l y z e the reactions of "tea f e r m e n t a t i o n . "

XVII

OH

OH

For a d d i t i o n a l information on work done on the e x t r a c t i o n , p u r i f i c a t i o n and p a r t i a l c h a r a c t e r i z a t i o n of tea catechol oxidase, see papers by Takeo (28), Takeo and U r i t a n i (29) and Gregory and Bendall (30). The work that e s t a b l i s h e s the r o l e of tea catechol oxidase as the c a t a l y s t f o r the o x i d a t i o n of the tea f l a v a n o l s during tea fermentation has been reviewed by Roberts ( 2 5 ) , Bokuchava and Skobeleva (31), and Sanderson ( £ ) . Peroxidase, The presence of peroxidase i n tea f l u s h was e s t a b l i s h e d as e a r l y as 1938 by Roberts and Sarma (8, 32). The enzyme i s r e a d i l y extracted from tea f l u s h (26), and^Hike tea catechol oxidase, r e t a i n s i t s a c t i v i t y even a f t e r exposure to the


20

ENZYMES


PROCESSING


tea f l a v a n o l s . The tea peroxidase enzyme has not been c h a r a c t e r ized except that i t i s reported to be composed of 6 or 7 i s o enzymes (33, 34). No r o l e has y e t been described f o r t h i s enzyme in black tea manufacture, but i t w i l l c a t a l y z e the o x i d a t i o n of tea f l a v a n o l s i f hydrogen peroxide i s present (8, 32, 35, 36). Tea M e t a l ! o p r o t e i n . L i n o l e i c and l i n o l e n i c acids a c t as black tea aroma precursors i n t h a t they are o x i d i z e d during f e r mentation to hexanal and 2 ( E ) - h e x e n a l , r e s p e c t i v e l y (37, 38). Recently, a m e t a l l o p r o t e i n present in tea leaves has Been shown (39) to be a non-enzymic f a c t o r that i s r e s p o n s i b l e f o r t h i s oxidation. L i p i d changes in the f i n i s h e d , f i r e d black tea have been i m p l i c a t e d (40) i n q u a l i t y changes t h a t occur during s t o r a g e . L i p o l y s i s has been shown to take place i n teas held under high humidity c o n d i t i o n s . On the other hand, l i p i d o x i d a t i o n was found to be most severe i n teas stored under dry c o n d i t i o n s at elevated temperatures. The non-enzymic nature of l i p o l y s i s and l i p i d o x i d a t i o n was demonstrated when tea heated a t 110°C f o r 15 min. showed the same amount of change in the l i p i d s during subsequent storage as unheated control samples of t e a . These r e s u l t s suggest that non-enzymic f a c t o r s , such as the m e t a l l o p r o t e i n c a t a l y z e d o x i d a t i o n of unsaturated f a t t y a c i d s , are important in determining the character of black t e a s . Pectin Methyl E s t e r a s e . The a c t i v i t y of t h i s enzyme i n tea leaves has been i m p l i c a t e d (41, 42) i n the control of the r a t e of fermentation by causing the formation of p e c t i c a c i d from methylated p e c t i n . This h y d r o l y s i s was shown to lead to reduced oxygen uptake when an anaerobic period preceeded fermentation. I t was suggested (42) that the demethylation causes some degree of gel formation anïï t h i s subsequently impedes oxygen d i f f u s i o n i n t o the macerated tea f l u s h , thereby i n h i b i t i n g tea fermentation. A l s o , well made black tea p a r t i c l e s have a dry hard p e c t i n l a y e r on t h e i r s u r f a c e : This p e c t i n coating i s supposed to prot e c t the q u a l i t y o f teas by a c t i n g as a b a r r i e r to water and oxygen, both of which promote r e a c t i o n s t h a t are involved i n loss of tea f l a v o r and the formation o f o f f - f l a v o r s . Alcohol Dehydrogenase. This tea enzyme, which has been studied e x t e n s i v e l y by Hatanaka and his co-workers (43-48), may be determining the amount of the l e a f a l c o h o l s 3(E)-hexenol, and 2(Z)-hexenol, and the corresponding a l d e h y d e s , t h a t are present in f i n i s h e d tea products. These v o l a t i l e compounds are important black tea aroma c o n s t i t u e n t s (1^2, 4 9 ) , which appear to enhance the f l a v o r q u a l i t y at c e r t a i n leveTT (50) but which are a s s o c i a ted with teas of poor q u a l i t y when present at high l e v e l s (51_,52). There appear to be two types of alcohol dehydrogenase i n tea f l u s h (46). The major one requires the co-enzyme n i c o t i n amide adenine dintacleotide (NAD) and the minor one needs n i c o t i n amide adenine d i n u c l e o t i d e phosphate (NADP). This means that the


2.


Manufacture of Bhck Tea and Instant Tea

21


l e v e l of these coenzymes, and t h e i r o x i d a t i o n s t a t e during tea fermentation, should be another f a c t o r that determines the l e v e l of l e a f a l c o h o l s , and t h e i r corresponding aldehydes, i n black tea. Transaminase. Wickremasinghe e t a l . (53, 54) have i d e n t i f i e d transaminase a c t i v i t y in macerated tea f l u s h . Wickremasinghe (54) suggests that t h i s enzyme i s involved i n the b i o s y n t h e s i s of terpenoid compounds that are important elements i n the aroma of good q u a l i t y black t e a s . Many f a c t o r s other than transaminase, some of which are a f f e c t e d by weather, are a l s o involved i n the b i o s y n t h e t i c systems that were proposed (54). Peptidase. There i s an increase i n the f r e e amino a c i d content of tea leaves during the withering period (about 18 h r . ) which follows p l u c k i n g . A peptidase enzyme has been shown to be present in tea f l u s h (55). This enzyme i s probably important in black tea manufacture because i t determines, i n p a r t , the l e v e l of f r e e amino acids i n tea f l u s h , and f r e e amino acids play a r o l e i n aroma formation ( F i g . 2) (12, 13). Phenylalanine Ammonia Lyase. Tea leaves have been shown (56) to contain phenylalanine ammonia l y a s e . This a c t i v i t y i s highest in the young leaves and decreases as the leaves grow larger. A p o s i t i v e c o r r e l a t i o n was observed between the a c t i v i t y of t h i s enzyme and catechin content as might be expected from an enzyme that i s known to be involved in f l a v a n o l b i o s y n t h e s i s . 5-Dehydroshikimate Reductase. This enzyme has been extracted from tea leaves i n an a c t i v e s o l u b l e s t a t e (57). The a c t i v i t y of t h i s enzyme was p a r t i c u l a r l y high i n tea f l u s h . This i s as would be expected of an enzyme which i s known to be involved in f l a v a nol b i o s y n t h e s i s and which i s endogenous in p l a n t material cont a i n i n g an e x t r a o r d i n a r i l y high l e v e l of polyphenolic compounds. Enzymes Involved In Instant Tea Manufacture (Table 2, Part B ) . Tannase. Cold water s o l u b i l i t y i s an important c h a r a c t e r i s t i c of i n s t a n t tea products s i n c e most i n s t a n t tea i s used to prepare iced t e a . The presence of "tea cream", a c o l d water i n s o l u b l e p r e c i p i t a t e that forms n a t u r a l l y i n brewed tea beverages when they are allowed to stand f o r a few hours at below about 40°C, i s t h e r e f o r e a major problem i n i n s t a n t tea manufacture (16). I t i s known (58-61) that tea cream i s a hydrogen bonded complex formed between the polyphenolic substances of black tea (IX-XVI) and c a f f e i n e (XXI). I t has been found (62, 63) that treatment of tea s o l i d s with the enzyme tannase causes most of the tea cream s o l i d s to become s o l u b l e i n cold water. Tannase i s a fungal enzyme obtained i n g r e a t e s t y i e l d from A s p e r g i l l u s sp. (64-66), and i t i s s p e c i f i c f o r the h y d r o l y s i s


22

ENZYMES


PROCESSING


o f e s t e r s of g a l l i c a c i d (XIX) ( £ 6 - 6 8 ) . The l a r g e s t part of the tea f l a v a n o l s (I-IV) i s e s t e r i f i e d with g a l l i c a c i d ( i . e . II and IV) and these g a l l o y l f l a v a n o l s are transformed i n t o g a l l o y l o x i d a t i o n products (IX-XVI where R=3,4,5-trihydroxybenzoyl) during the tea fermentation process (see Figure 1 ) . Further, i t is known that the preponderance of polyphenolic substances present i n tea cream are e s t e r i f i e d with g a l l i c a c i d (59).

CH

3

Some work has been done to prepare immobilized tannase (69, 70). These s t u d i e s i n d i c a t e that tannase can be s u c c e s s f u l l y immobilized using v i r t u a l l y a l l of the usual methods and support m a t e r i a l s a v a i l a b l e today. A process f o r the preparation o f cold water s o l u b l e i n s t a n t tea d i r e c t l y from f r e s h green tea f l u s h , which uses tannase in a "pre-conversion" treatment, has been described by Sanderson and Coggon ( 7 j ) . Polyphenol Oxidases. It was pointed out i n the s e c t i o n on the r o l e of tea catechol oxidase i n black tea manufacture t h a t the enzyme was c e n t r a l to the process by which green tea s o l i d s are converted to black tea s o l i d s . S e l t z e r , e t ^ a U (72) were the f i r s t to describe a process f o r the conversion of solTcTs e x t r a c t e d from green tea to black i n s t a n t tea s o l i d s u t i l i z i n g the catechol oxidase enzyme from other tea l e a v e s . In t h i s process green tea e x t r a c t i s obtained from any green tea leaves and macerated f r e s h green tea leaves c o n t a i n i n g a c t i v e tea catechol oxidase i s added to c a t a l y z e the c o n v e r s i o n . Oxygenation of aqueous tea l e a f homogenates has been des c r i b e d (73,74) as a means of preparing i n s t a n t tea products d i r e c t l y from f r e s h tea f l u s h . This kind of process makes use of the catechol oxidase endogenous to the tea f l u s h to e f f e c t the tea fermentation p r o c e s s . Polyphenol oxidases e x t r a c t e d from a number of d i f f e r e n t p l a n t m a t e r i a l s (ex. potato p e e l i n g s ; c a l l u s t i s s u e s of beans, sycamore, and apple p l a n t s ; and c e r t a i n molds) have been shown (75) to be capable of c a t a l y z i n g tea fermentation i n aqueous e x t r a c t s of green tea f l u s h . U n f o r t u n a t e l y , the cost o f these polyphenol oxidases i s probably p r o h i b i t i v e and t h e i r s t a b i l i t y is questionable.


2.



23


Peroxidase. A process t o prepare i n s t a n t tea d i r e c t l y from f r e s h tea f l u s h has been described (35,36) which u t i l i z e s the peroxidase enzyme that i s endogenous to tea f l u s h to c a t a l y z e the tea conversion p r o c e s s . These processes depend on adding hydrogen peroxide (F^Op) t o s t i r r e d homogenates o f f r e s h tea f l u s h . Of course, the added hydrogen peroxide acts as the o x i d i z i n g agent i n the tea fermentation process and the tea peroxidase serves as an e s s e n t i a l c a t a l y s t f o r the o x i d a t i o n o f the tea flavanols (I-IV). Pectinase. This enzyme has been described as being useful f o r improving the foam forming tendency o f i n s t a n t t e a powders (76). I t i s presumed that pectinase treatment o f t e a e x t r a c t s destroys some o f the natural pectins present which lowers the a b i l i t y o f the s o l i d s present t o form s t a b l e f i l m s . Cellulases. Fungal enzymes which f a l l i n t o t h i s general c l a s s i f i c a t i o n have been used to r e l e a s e useful s o l u b l e tea s o l i d s which are normally bound t o the tea leaves ( 7 7 , 7 8 ) . Summary The manufacture o f black tea i s e s s e n t i a l l y the mechanical manipulation o f f r e s h green tea f l u s h to cause a conversion o f the green tea s o l i d s t o black tea s o l i d s : This conversion i s c a t a l y z e d by enzymes that are endogenous to the tea f l u s h (Table 2, Part A ) . The enzymology and biochemistry o f the o x i dation o f the tea f l a v a n o l s to black tea pigments (Figure 1) appears to be understood a t l e a s t i n o u t l i n e . On the other hand, the enzymology and the chemistry o f the formation o f black tea f l a v o r , i . e . t a s t e and aroma (Figure 2 ) , i s only beginning to be understood. The d i f f i c u l t y o f e x t r a c t i n g enzymes from t i s s u e s r i c h i n polyphenolic compounds (10, 79-81) such as tea f l u s h has undoubtedly been an o b s t a c l e to more rapid development o f knowledge i n t h i s f i e l d . The manufacture o f i n s t a n t tea o f f e r s many i n t e r e s t i n g p o s s i b i l i t i e s f o r the use o f enzymes (Table 2, Part B ) . It w i l l be i n t e r e s t i n g to watch f u t u r e developments i n t h i s f i e l d . Literature Cited 1. 2. 3.

4.

Harler, C.R. (1963), "Tea Manufacture", Oxford Univ. Press, London, England, 126 pp. Eden, T. (1965), "Tea", 2nd E d . , Longmans, Green and C o . , L t d . , London, England. Hainsworth, E. (1969), "Encyclopedia of Chemical Technology", 2nd. E d . , Editor, A. Standen, pp. 743-755, Wiley (Interscience), New York. Sanderson, G.W. (1972), "Structural and Functional Aspects of Phytochemistry", Runeckles, V . C . , and Tso, T.C., E d . , Academic Press, New York, pp 247-316.


24

5. 6. 7.


8. 9. 10. 11. 12.

13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34.

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Pintaro, N. (1970), "Soluble Tea Processes", Park Ridge, N . J . , Noyes Data Corp. Sanderson, G.W. (1972), World Coffee & Tea, A p r i l , 1972, pp 54-57. Bamber, M.K. and Wright, H . , 1902, "Year Book of the Planters Association for 1901-1902", Planters Association, Colombo, Ceylon. Roberts, E . A . H . , and Sarma, S.N. (1938), Biochem. J. 32: 1819-1828. Sreerangachar, H.B. (1939), Current Sci., 8: 13. Sanderson, G.W. (1964), Biochim. Biophys. Acta. 92: 622-624. Buzun, G . A . , Dzhemukhadze, K.M., and Mileshko, L.F. (1970), P r i k l . Biokhim. Mikrobiol. 6: 345-347. Sanderson, G.W. (1975), "Geruch- und Geschmackstoffe", Drawert, F. (editor), Verlag Hans Carl, Nurenburg, W. Germany, pp 65-97. Sanderson, G.W., and Graham, H.N. (1973), J. Agric. Food Chem. 21: 576-585. Reymond, E. (1976) (ACS Centennial Symposium, New York City, A p r i l , 1976, to be published). Takeo, T. (1966), Agr. B i o l . Chem. 30: 931-934. Buzun, G . A . , Dzhemukhadze, K.M., and Mileshko, L.F. (1966), P r i k l . Biokhim. Mikrobiol. 2 (5): 609-11. Sanderson, G.W. (1964), J. S c i . Fd. Agric. 15: 634-639. Sanderson, G.W. (1964), Tea Quarterly 35: 101-110. Sanderson, G.W. and Kanapathipillai, P. (1964), Tea Quarterly 35: 222-229. Takeo, T., and Baker, J.E. (1973), Agr. B i o l . Chem. 12: 21-24. Sreerangachar, H.B. (1943), Biochem. J. 37: 653-655. Sreerangachar, H.B. (1943), Biochem. J. 37: 656-660. Sreerangachar, H.B. (1943), Biochem. J. 37: 661-667. Sreerangachar, H.B. (1943), Biochem. J. 37: 667-674. Roberts, E.A.H.(1962), "Chemistry of Flavanoid Compounds," Geissman, T . A . , e d . , pp 468-512, London, Pergamon Press. Coggon, P . , Moss, G . A . , and Sanderson, G.W. (1973), Phytochem. 12: 1947-1955. Sanderson, G.W. (1965), Biochem. J. 95: 24-25. Takeo, T. (1965), Agr. Biol. Chem. 29: 558. Takeo, T., and Uritani, I. (1966), Agr. B i o l . Chem. 30: 155-163. Gregory, R . P . F . , and Bendall, D.S. (1966), Biochem. J. 101: 569-581. Bokuchava, M.A., and Skobeleva, N.I. (1969), Advan. Food Res. 17: 215-280. Roberts, E.A.H. (1939), Biochem. J. 33: 836-852. Takeo, T., and Kato, Y. (1971), Plant and Cell Physiol. 12: 217-223. Tirimanna, A . S . L . (1972), J. Chromatogr. 65: 587-588.


2

SANDERSON

35. 36. 37. 38. 39.


40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64.

AND

COGGON


25

Fairley, C.J., and Swaine, D. (1973), British Patent No. 1,318,035, published May 23, 1975. Fairley, C.J., and Swaine, D. (1975), U.S. Patent No. 3,903,306, published Sept. 2, 1975. Gonzalez, J.G., Coggon, P. and Sanderson, G.W. (1972), J. Food S c i . 37: 797-798. Saijyo, R . , and Takeo, T. (1972), Plant and Cell Physiol. 13: 991-998. Coggon, P . , Romanczyk, L.J., and Sanderson, G.W. (1976), J. Agric. Fd. Chem. (in press). Stagg, G.V. (1974), J. S c i . Fd. Agric. 25: 1015-1034. Lamb, J., and Ramaswamy, M.S. (1958), J. S c i . Fd. Agric. 9: 46-51. Lamb, J., and Ramaswamy, M.S. (1958), J. S c i . Fd. Agric. 9: 51-56. Hatanaka, A. and Harada, T. (1972), Agr. B i o l . Chem. 36: 2033-2035. Hatanaka, A. and Harada, T. (1973), Phytochem. 12: 2341-2346. Kajiwara, T., Harada, T., and Hatanka, Α . , Agr. B i o l . Chem. 39: 243-247. Sekiya, J., Kawasaki, W., Kajiwara, T., and Hatanka, A. (1975), Agr. B i o l . Chem. 39: 1677-1678. Hatanaka, Α . , Sekiya, J., and Kajiwara, T. (1976), Phytochem. 15: 487-488. Sekiya, J., Numa, S., Kajiwara, T., and Hatanaka, A. (1976), Agr. B i o l . Chem. 40: 185-190. Yamanishi, T. (1975), Nippon Nogei Kagaku Kaishi 49: R1-R9. Tenco Brooke Bond Ltd. (1973), British Patent No. 1,306,017. Yamanishi, T., Wickremasinghe, R . L . , and Perera, K.P.W.C. (1968), Tea Quarterly 39: 81. Gianturco, M.A., Biggers, R . E . , and Ridling, B.H. (1974), J. Agric. Food S c i . 22: 758-764. Wickremasinghe, R . L . , Perera, B.P.M., and deSilva, U . L . L . (1969), Tea Quarterly 40: 26-30. Wickremasinghe, R.L. (7974), Phytochem. 13: 2057-2063. Sanderson, G.W., and Roberts, G.R. (1964), Biochem. J. 93: 419-423. Iwasa, K. (1974), Nippon Nogei Kagaku Kaishi 445. Sanderson, G.W. (1966), Biochem. J. 98: 548-252. Roberts, E.A.H. (1963), J. S c i . Food Agr. 14: 700-705. Wickremasinghe, R.L. and Perera, K.P.W.C. (1966), Tea Quarterly 37: 131-133. Smith, R.F. (1968), J. S c i . Fd. Agric. 19: 530-535. Rutter, P . , and Stainsby, G. (1975), J. S c i . Fd. Agric. 26: 455-463. Tenco Brooke Bond Ltd. (1971), British Patent No. 1,249,932. Takino, Y. (1976), U.S. Patent No. 3,959,497, issued 5/25/76. Yamada, K . , Iibuchi, S., and Mirada, Y. (1967), Hakko Kagaku Zasshi 45: 233-240.



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