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Fagopyrum 17: 63--66 2000

Rutin content in food products processed from groats leaves andflowers buckwheat

Cheol Ho PARK Yeon Bok KIM Yong Soon CHOI Kwon HEO Sun Lim KIMt

Ki Cheol LEE2, Kwang Jin CHANG3 and Han Bum LEECollege ofAgriculture and Life Sciences, Kangwon National University, Chunchon, 200-701. Korea

Department ofCropEnvironment, National Crop Experiment Station, Suwon, 441-100. Korea

2ChunchonNational UniversityofEducation. Chunchon, 200 703 , Korea

Korean National Agriculture College. Hwasung, 445-890, Korea Departmeni ofCrop Science, Kyeonggi Provincial Agriculture Technology. Hwasung, 445-970, Korea

Received September5, 2000; acceptedin revisedform September18,2000.

Key words: Fagopyrum species, flower tea, popped buckwheat groats, rutin content

ABSTRACTToassist in the develop of new buckwheat food products, the rutin content was analyzed in processed groats, leaves,

and flowers of buckwheat. The rutin content in the food products processed from groats, flowers, and leaves ofbuckwheat varied according to the processing method and plant part processed. The rutin content in seed derived

products ranged from 0.48mg/l gto 4.97mglI00g. The Korean var. Suwon 1 contained 28mg/l gof rutin before

boiling but this decreased to 0.5mgll gafter boiling. Popped groats 4.0mg/l g as well as powdered popped groats

5.0mg/100g showed higher rutin content than boiled groats. Flower tea had the highest rutin content, ranging from

396mg/100g first boiled tea to 78mg/l00g second boiled tea . There were big differences 74-301mg/100g among

the genotypes of common buckwheat and wild buckwheat species in rutin content of the liquid or powder when using

dried leaves.

INTRODUCTION

Buckwheat Fagopyrum esculentum Moench , familyPolygonaceae, classified as a pseudo-cereal, is a crop

adapted to cool, moist climates and to a growing season

60-70 days long. In Korea, the total area devoted to

the production of buckwheat was approximately 4600ha

in 1998. Buckwheat is marketed as flour for the manu

facture of noodles, and also as groats for several prod

ucts. is a crop species of considerable importance and

its use is now becoming more widespread due to its

high nutritive and pharmaceutical value Marshall and

Pomeranz, 1983; Choi et al., 1996; Shim et aI., 1998 .

Consumption in markets has already increased over the

past several years. is consumed mainly in the form of

noodles and dumplings. However, many people have a

desire in processing buckwheat materials to produce

high quality food products for health reasons. Especially,

the rutin content of buckwheat plants and food is a

matter of common interest to those for whom intensive

health care is needed. The rutin content in buckwheat

plants, including the leaf, stem, flower, root, groat, or

hull, has previously been reported in several research

papers Kim et aI., 1994; Choi et al., 1996; Shim et al.,

1998 but available information on rutin content in food

products made from buckwheat materials is very limited.In this paper we report on rutin content in processed

groats, leaves, and flowers of buckwheat as a strategy to

63

develop high quality food products.

MATERIALS AND METHODS

Korean common buckwheat cv. Suwon 1 and 8 intro

duced lines or species of buckwheat including Fagopy-

rum esculentum Youngwoljaerae , F tataricum, F ho-

motropicum, F cymosum (2x) from Kunming, Yunnan,

F cymosum (4x) from Baoshan, Yunnan F cymosum

(2x) from Heqin, Yunnan F statice from Chengjiang,

Yunnan, and F urophyllum from Luchen, Yunnan were

grown in the field at Chunchon. The 8 introduced lines

or species were kindly provided by Dr. O. Ohnishi, Plant

Germ-Plasm Institute, Kyoto University, Kyoto, Japan.

Seeds of Suwon 1 were harvested and used for making

beverage. The flowers and inflorecsences of Suwon 1

were picked at flowering time and dried in the shade

for making tea. Leaves of the 9 buckwheat lines were

harvested at flowering time and dried in an oven before

milling.

The pericarps of the seeds were removed and the

groats lOg were boi led in 500 ml of hot water for 10

min. Dehulled seeds were popped in a steel chamber

under high temperature and pressure. The popped groats

30 g, 109 were boi led in 500 ml hot water for 10 min.

The popped groats were ground by a mill to makepowder. The dried flowers and flower inflorescences of

buckwheat 2 g were boiled in 500 ml hot water for 10

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Table I.

Parket al.

Instrument and operating conditions for rutin analysis of9 buckwheat lines.

Instrument

Wave length

Column

Mobil phase

Flow rate

Shimazu SPD-7AVUV Detector

345 nm

IlBondapak C I8

Acetic acid (2.4 ) : Methanol : cetonitrile 35: 5 : 10 V/V)

1.0 ml/min

Table 2. Rutin content (mg/lOOg) in beverage made from processed buckwheat groats.

Food product Cultivar Use Rutin content

Boiled without popping Suwon I Beverage 0.48

Boiled after popped (30g) II II 4.00

Boiled after popped (lOg) II II 0.78

Milled after popped Snack 4.97

Table 3. Rutin content (mg/l g in tea made of flowers of buckwheat var. Suwon IProducts

Flower boiled for 10min

Second boiled one of flower boiled

Cultivar

Suwon I

Suwon I

Use

Tea

Tea

Rutin content

396

78.3

min to make tea.

The dried leaves of 4 species [ esculentum

(Youngwoljaerae), tataricum homotropicum and

cymosum (Kunming)] were boiled for 10min to maketea and leaves of the other 4 species [ cymosum

(Baoshan), cymosum (Heqin), statice urophyllum

were ground by a mill to make leaf powder. The rutin

content in each processed product was analyzed in three

replications by HPLC analysis (see Table 1) based on

the method ofKim et al. (1998) and expressed on a dry

weight basis.

RESULTS ND DIS USSION

The rutin content in food products processed from

groats, flowers, and leaves of buckwheat varied accord

ing to the processing method and plant part analyzed

(Fig. I). The rutin content in seed derived products

ranged from 0.48mg/l g to 4.97mg/l g (Table 2).

The popped groat contained more rutin in both boiled

water and as a powder when compared to water boiled

groats without popping. However, second boiled ex

tracts of popped groats showed markedly decreased

rutin content.

Kim et al. (1994) reported 13.4mg/IOOg rutin content

in buckwheat groats. Shim et al. (1998) compared the

rutin contents in groats among different Korean buckwheat cultivars. They found a wide range of rutin con

tent from 9.5mg/lOOg to 30.3mg/100g among the culti-

vars. However, they didn t process the groats, hence

they didn t analyze the rutin contents in food products

made from groats after processing. In this study, Suwon

1 contained 28mg l00g of rutin before boiling but thisdecreased to 0.5mg/lOOg after boiling. However,

popped groats showed a higher rutin content than boiled

groats (4.0mg/I00g) as well as powdered popped groats

(5.0mg/I00g). Further studies are required to clarify the

reason for the difference between popped groats and

non-popped groats.

As shown in Table 3, it is very interesting that tea

frombuckwheat flowers was the highest in rutin content.

ranged from 396mg/iOOg (first boiled tea) to 78mg/

100g (second boiled tea). Its rutin quantity is almost 80

fold as compared to that of the seed-derived beverage.

Buckwheat flower tea tastes very good, much like green

tea. It seems to have good potential for ccmmercializa

tion when mass production becomes possible and any

side effects which may occur from any other compo

nents in the flower have been tested. Kim et al. (1994)

analyzed 377.3mg/lOOgof rutin content in flowers from

buckwheat. Park (1964) found that 68 of the rutin

content was contained in the flowers at flowering time.

The present study is the first report to confirm the high

rutin content in buckwheat flower tea. The very high

rutin content in both flowers and flower tea indicates a

good potential for commercialization of buckwheatflowers.

There were big differences among the genotypes of

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Rutin content in food products

Table 4. Rutin content mgt l g) in foodstuffs made with dried leaves of different species of buckwheat.

Species Cult ivar or species Use Rutin content

esc ulentum Yongwoljaerae Tea 197.64

tat r icum Clfa

106.91

homotropicum Wild species 301.26F cymosum Kunming)

1/ 150.58

cymosum Baoshan)

/I 166.97

cymosum Heqin)

236.30

statice

74.54

F urop yllum

89.06

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Fig. I A: popped groat B: flower tea C: leaf powder

common buckwheat and wild buckwheat species in rutin

content of both the liquid or powder prepared by usingdried leaves Table 4). Fagopyrum homotropicum con

tained the highest rutin content 30Img /I00g) in tea

made of leaves, while statice and F urophyllum were

lowest in rutin content of powder from dried leaves

74-89mg/ lOOg). Kim et al. 994) r eported 4 4mgl

I g in rutin content of leaves at the flowering stage just

before seed setting. Their results arc simi lar to the

present study, although there were some differences in

rutin content among the genotypes. Ilowever, dried

leaves generally lost rutin content as compared to un

dried leaves. TIle loss of rutin on drying buckwheat was

reported to be 36 as a minimum and 100 as a maxi

mum Co uch et al., 1946). The drying methods were

responsible for the differences in the rates of lost rutin.

Rutin was lost most severely when the buckwheat leaves

were dried at a low temperature over a long time. Ther e

fore, buckwheat leaves must be dried in a short time at a

high temperature for making high rutin tea and powder.

CKNOWLEDGEME TS

The author s wish to thank Dr. O. Ohn ishi, Plant Germ

Plasm Institute , Kyoto University. for kindly supplying seeds

ofwild species of Fagopyrum.

REFERENCES

Couch J. E, J. Naghski and C. F. Krewson, 1946. Buckwheat as a

source of rutin. Science February) : 197-198 .

Choi, B. H., S. L. Kim and S. K. Kim, 1996. Rutin and functionalingredients of buckwheat and their variations. Korean J. Crop

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Kim, S. K., Y. K. Son, J. J. IIwang, S. K. Kim and H. S. Hur, 1998.

Development of buckwheat sprout as a functional vegetable.

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Kim, J. S., Y. J. Park, M. H. Yang and J. W. Shim, 1994. Variation

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F agopyrum esculentum Moench ). Korean J. Breed, 26: 384

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Rutin and mineral contents on improved kinds of Korean buck

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Marshall, H. G and Y. Pomeranz, 1983. Buckwheat: Description.

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and Technology. 5: 157- 210.

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