Botanical Studies (2008) 49: 215-224.

*

Corresponding author: E-mail: ccnee@dragon.nchu.edu.tw;

Fax: +886-4-22840340; Tel: +886-4-22840340.

INTRODUCTION

Kiwifruit (genus Actinidia) originated in China,

and although more than 60 species belong to the genus

Actinidia, few have economic importance (Ferguson,

1990). Rassam and Laing (2005) observed that A .

deliciosa and A. chinensis are the most common species

worldwide. The eight species: A. setosa, A. latifollia Merr,

A. arguta, A. callosa Lindl. var. callosa, A. callosa Lindl.

var. ephippioidea, A. rubricaulis, A. rufa Planch, and A.

tetramera are native to Taiwan (Flora of Taiwan, 1996).

In 1990, A. setosa branches were collected from different

areas on Ma Mountain in Taichung County for the

Department of Horticulture at the National Chung Hsing

University, Taiwan. These cuttings were grafted, and the

experimental vine A. setosa ¡¥No. 9¡¦ was selected because

it produced the largest fruit. Actinidia deliciosa ¡¥Chung

Hsing No.3¡¦ (¡¥CH3¡¦) and ¡¥Chung Hsing No.4¡¦ (¡¥CH4¡¦)

were seedlings from A. deliciosa ¡¥Bruno¡¦ (Chou and Nee,

2004; 2005; 2006).

Kiwifruit typically requires 25 weeks from anthesis to

reach physiological maturity¡Xthe earliest time at which

fruit can be picked and continue to ripen satisfactorily

(Beever and Hopkirk, 1990). The fruit is very hard while

developing; however, firmness declines slightly during the

latter stages of development (Gallego and Zarra, 1998).

Characterization of the physico-chemical and antioxidant

properties of Taiwanese kiwifruit (Actinidia setosa)

Hui-Na CHOU

1

, Cheng-Chu NEE

1,

*, Andi Shau-Mei OU

2

, Tse-Heng CHOU

3

,

and Chia-Chen

CHIEN

4

1

Department of Horticulture, National Chung Hsing University, Taichung, Taiwan, Republic of China

2

Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China

3

Department of Electronic Engineering, Wufeng Institute of Technology, Min Shong Township, Chia Yi, Taiwan, Republic

of China

4

Meilin Elementary School, Shi Kou Township, Chia Yi, Taiwan, Republic of China

(Received October 16, 2006; Accepted February 21, 2008)

ABSTRACT.

In Taiwan the kiwifruit Actinidia setosa grows higher than 1,500 m above sea level. The

National Chung Hsing University of Taiwan maintains a collection of experimental vines grown from cuttings

of the native A. setosa collection. Actinidia setosa ¡¥No.9¡¦, which produced the largest fruit, was selected

for a study of its physicochemical and antioxidant characteristics, which were compared with those of A.

deliciosa ¡¥Chung Hsing No.3¡¦ and ¡¥Chung Hsing No.4¡¦. Kiwifruit fresh weight, soluble solids content, flesh

firmness, titratable acidity, quinic, malic, ascorbic and citric acid contents, chlorophyll content, total phenol

compound content, peroxidase activity, polyphenolic oxidase activity, free radical scavenging (DPPH) effect,

and chelating effect were measured. Anthesis of A. setosa and A. deliciosa occurs in late April and late May,

and fruit maturity occurs in late September and late October, respectively. The strong insect and disease-

resistant characteristics of A. setosa ¡¥No.9¡¦ can be attributed to the long down on the branches, leaves, and

fruit. Actinidia setosa ¡¥No.9¡¦ has a yellow rust leaf infection rate of 14¡Ó3% while that of ¡¥Chung Hsing No.3¡¦

and ¡¥Chung Hsing No.4¡¦ leaves was 77¡Ó5% and 92¡Ó7%, respectively. The A. setosa ¡¥No.9¡¦ fruit has a flat,

long shape with a down length of 33¡Ó4 £gm, and the down length on ¡¥Chung Hsing No.3¡¦ and ¡¥Chung Hsing

No.4¡¦ fruit was 18.2¡Ó0.7 and 17¡Ó4 £gm, respectively. Under organic cultivation, A. setosa ¡¥No. 9¡¦ had a mature

fruit fresh weight of 66¡Ó10 g, soluble solids content of 6.2¡Ó0.1 ¢XBrix, and titratable acidity of 2.2¡Ó0.0%. In A.

setosa ¡¥No.9¡¦ the ascorbic acid concentration was 83¡Ó6 mg/100 g, malic acid was 565¡Ó9 mg/100 g, and the

total phenol compound content was 0.4¡Ó0.1 mg/g of fresh weight, all significantly higher than those of ¡¥Chung

Hsing No.4¡¦. The peroxidase and polyphenolic oxidase activities of A. setosa ¡¥No.9¡¦ were 0.02¡Ó0.0 .A

470

/

min/g.fw and 0.01¡Ó0.0 .A

420

/min/g.fw at 150 days after anthesis (DAA), respectively. The DPPH ability of A.

setosa ¡¥No.9¡¦, ¡¥Chung Hsing No.3¡¦ and ¡¥Chung Hsing No.4¡¦ was 96.1¡Ó0.2%, 93¡Ó1% and 95¡Ó1%, respectively.

The experimental results indicate that A. setosa ¡¥No.9¡¦ has great potential for commercial production and

breeding.

Keywords: Actinidia setosa ¡¥No.9¡¦; Actinidia deliciosa; Ascorbic acid content; ¡¥Chung Hsing No.3¡¦; ¡¥Chung

Hsing No.4¡¦; DPPH and soluble solids content.

BIOCHEMISTRY

216

Botanical Studies, Vol. 49, 2008

These changes in firmness involve changes to cell wall

structure. Internal soluble solid concentrations (SSCs) are

utilized as the maturity index for kiwifruit in New Zealand

(Beever and Hopkirk, 1990), and in Chile and New

Zealand, a value of at least 6.2% SSC is used (Crisosto and

Crisosto, 2001). According to the University of California,

¡¥Hayward¡¦ fruit can be harvested when its SSC reaches a

minimum of 6.5% (Crisosto and Crisosto, 2001).

Ascorbic acid (Vitamin C) in fruits and vegetables is

considered an important component for human nutrition.

More than 90% of the ascorbic acid in the human diet

comes from fruits and vegetables (Lee and Kader,

2000). Ascorbic acid, as an antioxidant, is associated

with a decreased risk of arteriosclerosis, cardiovascular

diseases, and some forms of cancer (Harris, 1996).

The polyphenolic compounds (flavonoids) also have

antioxidant characteristics and can account for some

benefits associated with the consumption of fruits and

vegetables (Wong et al., 2006).

Peroxidase (POD, EC 1.11.1.7) is an enzyme located

in several subcellular compartments such as chloroplasts

(Kuroda et al., 1990). Polyphenolic oxidase (PPO, EC

1.10.3.2) is a copper-containing enzyme which acts on

phenols in the presence of oxygen (Haruta et al., 1999).

The pro- and anti-oxidant enzymes, such as peroxidase

(POD), superoxide dismutase (SOD), and catalase (CAT)

(Wang et al., 2005). POD requires a hydrogen donor

for its degradation of H

2

O

2

(Abassi et al., 1998). PPO is

suggested to act as a defensive enzyme (Mayer and Harel,

1990). The oxidation of phenolic compounds by PPO

may, however, also enhance the bioavailability of iron in

food from plants containing polyphenol (Matuschek and

Svanberg, 2005). Oxidation of phenolic compounds may

result in a reduced iron-binding capacity and a higher

availability of iron (Matuschek and Svanberg, 2005).

Health professionals advocate the consumption of fruit and

vegetables to protect against degenerative diseases such

as coronary heart disease, cancers, and other free radical-

mediated conditions (Kritchevsky, 1999). Fruits and

vegetables contain numerous compounds which display

antioxidant activities. These compounds include vitamin

C and E, phenolics, and carotenoids (Burns et al., 2003;

Kondo et al., 2005).

Actinidia setosa is a kiwifruit endemic to Taiwan

at elevations above 1,500 meters (m). This species

displays a greater resistance to Yellow rust infection and

Sympiezomios velatus infestation compared to A. deliciosa

and A. chinensis (Xiao, 2000). In this paper we describe

the measurement of some physicochemical and antioxidant

components and the characteristics of A. setosa fruit.

MATERIALS AND METHODS

Materials

Actinidia setosa ¡¥No.9¡¦, A. deliciosa ¡¥CH3¡¦ and ¡¥CH4¡¦

fruit were harvested from vines, grown in the experimental

farm at the Department of Horticulture at the National

Chung Hsing University (altitude 1,900-2,100 m), during

the 2003 growing season in Taiwan. Kiwifruit samples

were collected at the start of anthesis to calculate the date

at 100 and 150 DAA. After harvesting, the fruit was stored

at 4¢XC in a laboratory refrigerator for fruit analysis. The

anthesis seasons of A. setosa and A. deliciosa are late April

and late May, respectively. Mature A. setosa fruit was

harvested on September 24 and mature ¡¥CH3¡¦ and ¡¥CH4¡¦

fruits were harvested on November 1. Each laboratory test

on these fruits was performed six times.

Microscope observation and infection

percentage

The branches, leaves, and fruit were examined

utilizing an anatomy microscope (WILD LFITZ, M

32) at magnifications of 16¡Ñ (branches and fruit) and

40¡Ñ (leaves) (Ontivero et al., 2005). The down length

of branches, leaves and fruit were measured for the

objective micrometer under the eyepiece on the anatomy

microscope. The percentage of yellow rust infection on

leaves was measured.

Fresh weight, fruit length, and diameter

The fruit were weighed using a digital balance

(METTLER TOLEDO, PB3002-S). Fruit length

(from stem and distal end) and maximum diameter

were measured using digital calipers (MITUTOYO

CORPORATION, CD-6" BS, Japan) (Smith et al., 1995).

Flesh firmness, SSC and titratable acidity

Flesh firmness was recorded by puncturing the

fruit using a penetrometer (EFFEGI, Italy) fitted with

a flat 7.2-mm-diameter tip. The SSC in the fruit juice

was measured using a refractometer (ATAGO N-1E,

Japan) (Antunes and Sfakiotakis, 2002). The titratable

acid content was measured using an automatic titrator

(METTLER DL25 Titrator, Sweden). Titration was

conducted with 0.1 N NaOH at pH 8.1, and the percentage

of citric acid equivalents was determined (Agar et al.,

1999; Luo, 2006).

Flesh color

A hand-held colorimeter (Nippon Denshoku, NR-3000)

was utilized to measure flesh in the CIE L*a*b* mode.

(Agar et al., 1999; Antunes and Sfakiotakis, 2002). The

L* value represents the lightness of colors. The a* value

is negative for green and positive for red. The b* value is

positive for yellow and negative for blue (Lee et al., 2005).

Organic acid content

20-30 g of fruit was ground in a juicer and added

to a 90-ml volume of distilled water. The extract was

centrifuged at 15,000 rpm and 4¢XC and filtered through

a 0.45

£g

m filter. Quinic, malic, ascorbic, and citric acid

analyses were performed by HPLC (Hitachi L-6000

pump), on a reverse phase C-18 column 250¡Ñ4.6 mm and

a mobile phase of 2% KH

2

PO

4

in H

3

PO

4

. Flow rate was 1.0

CHOU et al. ¡X

Taiwanese kiwifruit (

Actinidia setosa

)

217

ml min

-1

, and injection volume was 10

£g

l. A UV detector

(Model L-4000 UV Detector) was set at 214 nm. All data

were compared to standard curves of authentic quinic,

malic, ascorbic, and citric acids (Iwasa, 1975; Wang,

2006).

Total phenolic compound content

The total phenolic compound was extracted from 2

g of flesh tissue with 10 ml of cold 0.1 M phosphate

buffer, pH 7.0 at 4¢XC. Total phenolic compounds were

measured using the Folin-Ciocalteu method (Keith et al.,

1958). One ml of extract was added to 0.1 ml of Folin-

Ciocalteu phenol reagent, 0.2 ml of 20% Na

2

CO

3

, and 8.7

ml distilled water. The mixture was boiled for 3 min and

cooled immediately. The resulting blue complex was then

measured at 660 nm. Caffeic acid (Sigma) was utilized

to plot the standard curve, and analytical results were

expressed as mg of caffeic acid equivalent per g of fresh

weight (Hou et al., 2004; Huang et al., 2004).

POD and PPO activity

The POD and PPO were extracted from 2 g of flesh

tissue with 2 ml of cold 0.1 M phosphate buffer, pH 7.0,

containing 1% PVP (polyvinylpyrrolidone) (Sigma) and

0.25% Triton at 4¢XC. The homogenate was centrifuged for

20 min at 15,000 rpm, and the supernatant was utilized

to determine POD and PPO activity (Asada, 1984). The

assay mixture contained 0.2 ml enzyme extract, 2 ml 3.6

¡Ñ10

-3

M guaiacol (2-methoxyphenol) (Sigma), 0.3 ml

distilled water, and 0.2 ml 0.0135 M H

2

O

2

. Oxidative loss

of guaiacol was followed by an increase in the absorbance

at 470 nm, according to a spectrophotometer (Hitachi

U-2000). The POD activity was presented as .A

470

/min/

g.fw (Gong et al., 2001; Torres et al., 2003).

To measure PPO activity, the reaction chamber

contained 0.1 ml enzyme extract, 1. 9 ml 0.1 M phosphate

buffer (pH 8.0), and 0.2 ml 0.5 M catechol (Sigma). The

oxidation of catechol to benzoguinone was followed by

an increase in its absorbance at 420 nm as measured by

spectrophotometer. The PPO activity was presented as

.A

420

/min/g.fw.

Scavenging activity of 1, 1-diphenyl-2-

picrylhydrazyl (DPPH) radical and chelating

effect

Samples were extracted from 4 g of flesh tissue with 20

ml of methanol at 4¢XC. The homogenate was centrifuged

for 20 min and the supernatant was used to determine

DPPH-radical scavenging and iron chelating effects. A

new paragraph is needed here with the heading "DPPH

scavenging" 2 ml of extract was added to 0.5 ml 0.5 mM

DPPH-MeOH, and the combination was mixed and kept

for 30 min at room temperature in the dark. The reduction

in the DPPH absorbance (517 nm) was measured with a

spectrophotometer (Kondo et al., 2002). The scavenging

activity of DPPH radicals (%) was calculated using the

following equation: [1- (A517

sample

¡Ò A517

blank

)] ¡Ñ 100%

(Hou et al., 2004).

Iron chelation

1 ml of extract was added to a solution of 3.7 ml

of methanol and 0.1 ml of 2 mM FeCl

2

¡P4H

2

O, and

allowed to stand at room temperature for 30 seconds.

After adding to 0.2 ml 5 mM ferrozine (3-(2-pyridyl)-

5,6-di (p-sulfophenyl)-1,2,4-triazine Disodium Salt),

the mixture was shaken vigorously and left to stand

at room temperature for 10 min. When the mixture

reached equilibrium, its absorbance was measured

spectrophotometrically at 562 nm. The percentage of

inhibition of ferrozine-Fe

2+

complex formation was

obtained using the formula: [1-(A562

sample

¡Ò A562

blank

)] ¡Ñ

100% (Dinis et al., 1994; Gulcin et al., 2004).

Statistical analysis

Data were subjected to an analysis of variance

(ANOVA) to determine whether differences existed

between treatments. Duncan¡¦s least significant differences

(LSDs) were calculated to compare the difference between

means following a significant ANOVA effect (Marsh et

al., 2004). A value of P<0.05 was considered statistically

significant. Standard errors were calculated using

Microsoft Excel.

RESULTS

Characters of branch, leaf and fruit

Table 1 shows the down length on the branches, leaves,

and fruit, and the yellow rust coverage on A. setosa ¡¥No.9¡¦,

¡¥CH3¡¦ and ¡¥CH4¡¦ leaves. The down length on A. setosa

¡¥No.9¡¦ branches (18¡Ó1 £gm), leaves (5¡Ó1 £gm), and fruit (33

¡Ó4 £gm) was significantly longer than that for both ¡¥CH3¡¦

and ¡¥CH4¡¦ (Figure 1). The low infection rate of A. setosa

¡¥No.9¡¦ by yellow rust (14¡Ó3% coverage) was correlated

with its leaf down length. Infection by yellow rust was 77

¡Ó5% for ¡¥CH3¡¦ and 92¡Ó7% for ¡¥CH4¡¦.

Effects of maturity on the fruit physico-chemical

components

Table 2 lists physical and chemical properties of A.

setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ fruit at 100 DAA. Fresh

weight of A. setosa ¡¥No.9¡¦ was 54¡Ó3 g; fruit length was

68¡Ó2 mm; and diameter was 46¡Ó2 mm. The fresh weight

and length of kiwifruit samples were significantly different

(P<0.05); however, the diameters were not significantly

different. Actinidia setosa ¡¥No.9¡¦ fruit flesh firmness and

SSC were 144¡Ó5 N and 3.2¡Ó0.1 ¢XBrix, 188¡Ó6 N and 3.5¡Ó

0.1 ¢XBrix for ¡¥CH4¡¦. The fruit flesh color values L, a and

b were influenced by the green flesh. The L and a values

did not difffer significantly between fruits. The content of

quinic acid was highest at the start of fruit development

and decreased. The fruit quinic acid content was 1462¡Ó35

mg/100 g, malic acid content was 482¡Ó24 mg/100 g, and

citric acid content was 1116¡Ó74 mg/100 g for A. setosa

¡¥No.9¡¦.

218

Botanical Studies, Vol. 49, 2008

Table 1. Down length on the branches, leaves and fruit, and yellow rust infection of the leaves A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at

150 DAA.

Characteristics

A. setosa ¡¥No.9¡¦

¡¥

CH3¡¦

¡¥

CH4¡¦

Branch down (£gm)

18¡Ó1 a

a

4.5¡Ó0.2 b

b

5¡Ó1 b

Leaf down (£gm)

5¡Ó1 a

3.2 ¡Ó0.5 b

2.2¡Ó0.3 b

Fruit down (£gm)

33¡Ó4 a

18.2¡Ó0.7 b

17¡Ó4 b

Yellow rust infection (%)

14¡Ó3 b

77¡Ó5 a

92¡Ó7 a

a

Values are means ¡Ó standard error.

b

Means in the same row, followed by the same letter are not significantly different at the 5% level.

Figure 1. Microscopic observation of kiwifruit sample down at 150 DAA. Branch (A), leaf (B) and fruit (C) of A. setosa ¡¥No.9¡¦.

Branch (D), leaf (E) and fruit (F) of ¡¥CH4¡¦. (Bars = 10 £gm for A, C, D, F and 5 £gm for B, E).

CHOU et al. ¡X

Taiwanese kiwifruit (

Actinidia setosa

)

219

The fruit fresh weight of A. setosa ¡¥No.9¡¦ was 66¡Ó10 g

(Table 3). The fruit fresh weights for ¡¥CH3¡¦ and ¡¥CH4¡¦ at

150 DAA were 102¡Ó5 g and 111¡Ó4 g, respectively (Figure

2). Kiwifruit sample SSCs achieved harvest standards.

Actinidia setosa ¡¥No.9¡¦ had 6.2¡Ó0.1 ¢XBrix. Titratable

acidity was calculated for citric acid, and kiwifruit

titratable acidity demonstrated significantly different

effects (P<0.05). All kiwifruits had green flesh with L, a

and b values of 45.8¡Ó0.9, -11.4¡Ó0.3 and 18.9¡Ó0.3 for A.

setosa ¡¥No.9¡¦. Quinic acid, malic acid, and citric acid,

were the principal organic acids. Malic acid content for

A. setosa ¡¥No.9¡¦ and ¡¥CH4¡¦ was significantly different;

however the citric acid contents were not significantly

different at maturity.

Effects of maturity on fruit antioxidant

components and antioxidant characteristics

Figure 3A shows that the ascorbic acid content of

kiwifruit was significantly different at 100 DAA and 150

DAA. Actinidia setosa ¡¥No.9¡¦ had ascorbic acid content

that was higher than ¡¥CH4¡¦ and lower than ¡¥CH3¡¦.

Ascorbic acid content for A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦, and

Table 2. Properties of the fruit of A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at 100 DAA.

Components

A. setosa ¡¥No.9¡¦

¡¥

CH3¡¦

¡¥

CH4¡¦

Fresh weight (g)

54¡Ó3 c

a

81¡Ó5 a

b

68¡Ó3 b

Fruit length (mm)

68¡Ó2 b

74¡Ó2 a

61.9¡Ó0.6 c

Fruit diameter (mm)

46¡Ó2 a

47¡Ó2 a

45.6¡Ó0.8 a

Flesh firmness (N)

144¡Ó5 b

136¡Ó13 b

188¡Ó6 a

SSC (¢XBrix)

3.2¡Ó0.1 b

3.8¡Ó0.2 a

3.5¡Ó0.1 ab

Titratable acidity (%)

4.6¡Ó0.2 a

3.7¡Ó0.2 b

2.8¡Ó0.2 c

Flesh color (L)

47.2¡Ó0.7 a

49¡Ó1 a

48¡Ó0.2 a

Flesh color (a)

-12.5¡Ó0.4 a

-12.2¡Ó0.5 a

-12.4¡Ó0.5 a

Flesh color (b)

21¡Ó0.7 b

22.6¡Ó0.4 a

22.5¡Ó0.4 a

Quinic acid (mg/100 g)

1462¡Ó35 a

1169¡Ó49 b

1520¡Ó40 a

Malic acid (mg/100 g)

482¡Ó24 a

531¡Ó63 ab

355¡Ó13 b

Citric acid (mg/100 g)

1116¡Ó74 ab

1303¡Ó173 a

912¡Ó119 b

a

Values are means ¡Ó standard error.

b

Means in the same row, followed by the same letter are not significantly different at the 5% level.

Table 3. Properties of the fruit of A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at 150 DAA.

Components

A. setosa ¡¥No.9¡¦

¡¥

CH3¡¦

¡¥

CH4¡¦

Fresh weight (g)

66¡Ó10 b

a

102¡Ó5 a

b

111¡Ó4 a

Fruit length (mm)

73¡Ó1 b

83¡Ó1.7 a

71.7¡Ó0.9 b

Fruit diameter (mm)

44¡Ó0.8 c

49¡Ó1 b

53¡Ó1 a

Flesh firmness (N)

73¡Ó7 c

171¡Ó7 b

197¡Ó8 a

SSC (¢XBrix)

6.2¡Ó0.1 c

8.9¡Ó0.5 a

7.5¡Ó0.2 b

Titratable acidity (%)

2.2¡Ó0.0 c

3.7¡Ó0.2 a

2.8¡Ó0.2 b

Flesh color (L)

45.8¡Ó0.9 b

49.2¡Ó0.9 a

47.4¡Ó1 ab

Flesh color (a)

-11.4¡Ó0.3 a

-12.9¡Ó0.4 b

-12.2¡Ó0.3 ab

Flesh color (b)

18.9¡Ó0.3 b

22.0¡Ó0.4 a

22.0¡Ó0.5 a

Quinic acid (mg/100 g)

1384¡Ó46 a

1023¡Ó50 b

1430¡Ó38 a

Malic acid (mg/100 g)

565¡Ó9 a

471¡Ó63 a

228¡Ó2 b

Citric acid (mg/100 g)

1463¡Ó46 ab

1655¡Ó46 a

1361¡Ó45 b

a

Values are means ¡Ó standard error.

b

Means in the same row, followed by the same letter are not significantly different at the 5% level.

220

Botanical Studies, Vol. 49, 2008

¡¥CH4¡¦ was 83¡Ó6 mg/100 g, 119¡Ó6.0 mg/100 g, and 56¡Ó

3 mg/100 g, respectively. The kiwifruit had significantly

higher phenolic content at the start of fruit development,

but this decreased as the fruit matured. Fruit total phenolic

compound contents of A. setosa ¡¥No.9¡¦ were 0.5¡Ó0.0 mg/

g and 0.4¡Ó0.1 mg/g at 100 and 150 DAA, respectively

(Figure 3B). Total phenol content in A. setosa ¡¥No.9¡¦ was

significantly higher than in ¡¥CH3¡¦ (P<0.05) at maturity.

Figure 4A presents the POD activity for A. setosa

¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦. Actinidia setosa ¡¥No.9¡¦ and

¡¥CH4¡¦ activities did not differ significantly at either 100

or 150 DAA fruit POD. The POD activity of ¡¥CH3¡¦ was

higher than that of the other two cultivars at both 100

DAA and at maturity. All three fruits displayed lower POD

activity (5 fold) at 150 DAA than at 100 DAA. Fruit PPO

activity for A. setosa ¡¥No.9¡¦ was not significantly different

at 100 DAA and 150 DAA (Figure 4B). The PPO activity

for A. setosa ¡¥No.9¡¦ and ¡¥CH4¡¦ was 0.01¡Ó0.0 and 0.02¡Ó0.0

.A

420

/min/g.fw, respectively.

The free radical scavenging activity of fruit extracts

of A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦, and ¡¥CH4¡¦ were tested using

the DPPH technique (Table 4). Free radical scavenging

activities for all kiwifruit samples were >90%. The fruit

DPPH activities of A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH 4¡¦

were 95.3¡Ó0.3%, 95.3¡Ó0.1% and 95.6¡Ó0.3% at 100 DAA,

respectively. However, DPPH activities of A. setosa ¡¥No.9¡¦

had stronger radical scavenging ability than did ¡¥CH3¡¦ at

maturity. Actinidia setosa ¡¥No.9¡¦ 11¡Ó2% and ¡¥CH4¡¦ 10¡Ó

1% had higher ferrous ion chelating capability than ¡¥CH3¡¦

6¡Ó1% at 100 DAA (Table 4).

DISCUSSION

In today¡¦s business environment, a continuous supply

of novel products is essential to retaining a competitive

advantage (Jaeger et al., 2003). Thus new product

development is the key to survival and has driven the

industry to initiate large breeding programmes to formalise

the development of new cultivars (Jaeger et al., 2003). Stec

et al. (1989) found that parameters such as aroma intensity

and acceptability, sweetness, acidity, and ripe fruit flavour

were significantly affected by the firmness of the fruit.

The A. setosa only grows at elevations >1,500 m in

Taiwan. The relatively high insect and disease-resistant

characteristics of A. setosa are attributable to the length of

the down on its branches, leaves, and fruit. For A. setosa

¡¥No.9¡¦ these lengths are longer than on either ¡¥CH3¡¦ or

¡¥CH4¡¦, and both suffer a high rate of yellow rust infection.

yellow rust spore reproduction is attributable to the

temperature, water, and other environmental conditions on

kiwifruit leaves. The strong disease-resistance of A. setosa

is attributable to the long down on its leaves.

The largest fruit, A. setosa ¡¥No.9¡¦, had a mature

fresh weight of 66¡Ó10 g; fruit length was 73¡Ó1 mm, and

diameter was 44¡Ó0.8 mm. Fruit Fresh weights for A .

setosa grown at an experimental farm by the Department

of Horticulture at National Taiwan University (altitude

2,300 m) and the On Ma Mountain Peaceful Township in

Taichung County (altitude 2,000 m), Taiwan, were 24.3¡Ó

Table 4. % Scavenging of the DPPH radical by extracts of A. setosa ¡¥No. 9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at 100 DAA and 150 DAA, and Fe

2+

chelation (%) of kiwifruit samples at 100 DAA.

Characteristics

100 DAA

150 DAA

A. setosa ¡¥No.9¡¦

¡¥

CH3¡¦

¡¥

CH4¡¦

A. setosa ¡¥No.9¡¦

¡¥

CH3¡¦

¡¥

CH4¡¦

DPPH effect (%)

95.3¡Ó0.3 a

a

95.3¡Ó0.1 a

b

95.6¡Ó0.3 a

96.1¡Ó0.2 a 93¡Ó1 b 95¡Ó1 ab

Iron (Fe

2+

) chelation (%)

11¡Ó2 a

6¡Ó1 b

10¡Ó1 a

-

c

-

-

a

Values are means ¡Ó standard error.

b

Means in the same row, followed by the same letter are not significantly different at the 5% level.

c

No data.

Figure 2. The fruit shape of A. setosa ¡¥No.9¡¦ (A), ¡¥CH3¡¦ (B1)

and ¡¥CH4¡¦ (B2) at 150 DAA.

CHOU et al. ¡X

Taiwanese kiwifruit (

Actinidia setosa

)

221

0.3 g and 22¡Ó1 g, respectively. The SSC and flesh firmness

of kiwifruit were utilized as an index of maturation and

harvesting time. In this study, A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦

and ¡¥CH4¡¦ all attained the harvest standard at 150 DAA.

Generally, starch content rapidly decreases and SSC

rapidly increases at maturity. Chlorophyll degradation

is characteristic of fruit ripening (Martinez et al., 2001);

however, flesh color is attributable to the chlorophyll

content. Average ascorbic acid for A. setosa ¡¥No.9¡¦ was

83¡Ó3 mg/100 g, and the highest was 104¡Ó6 mg/100 g for

¡¥CH3¡¦ at 150 DAA. Fruit ascorbic acid content differs

according to habitat, harvest temperature, amounts of

sunshine and rainfall, cultivation management, and

measuring techniques (Gonzalez Rodriguez et al., 1993).

Ascorbic acid increases rapidly during mid-season when

seeds enlarge and fruit growth slows (Okuse and Ryugo,

1981). Gonzalez Rodriguez et al. (1993) determined that

quinic acid concentrations exceeded those of the other

acids at the start of fruit growth and then decreased as fruit

matured.

Kiwifruit has more ascorbic acid than fruits such as

cashew apples (Assuncao and Mercadante, 2003), bananas,

papayas, longan, lychees,

and rambutan (Wall, 2006). The

ascorbic acid content of ¡¥Abbott¡¦ and ¡¥Monty¡¦ were 159.20

mg/100 g and 164.05 mg/100 g, respectively (Chou and

Nee, 2005). The current recommended dietary allowance

(RDA) for ascorbic acid for adult nonsmoking men and

women is 60 mg/day, based on a mean requirement of 46

mg/day to prevent scurvy (Carr and Frei, 1999). More

attention has been paid to the antioxidants contained in

fruits because epidemiological studies have revealed high

fruit intake to be associated with reduced mortality and

morbidity of cardiovascular disease and some types of

cancer, and one of the possible mechanisms involves the

antioxidant activity present in the fruits (Lampe, 1999;

Guo and Yang, 2001).

Total phenolic content of kiwifruit, oranges, apples, and

pears was 0.22, 0.51, 0.48 and 0.12 g/100 g of fresh weight

(Cai et al., 2004). In this study, total phenolic content

was significantly different between 100 and 150 DAA.

Kiwifruit total phenolic content was highest at the initial

growth period. The PPO activity varied significantly, likely

depending on the fruit species, cultivar, stage of maturity,

analytical methods, and experimental extraction conditions

(Nicolas et al., 1994). Kiwifruit POD and PPO activity

were both low at 100 and 150 DAA. The PPO activity for

Psidium guajava ¡¥Shui-Jing Bar¡¦ and ¡¥Li-Tzy Bar¡¦ was

3 and 2 .A

420

/min/g.fw at maturity, respectively (Hang,

2002). The POD activity for Psidium guajava ¡¥Shui-Jing

Bar¡¦ and ¡¥Li-Tzy Bar¡¦ was 0.8 and 1.1 .A

470

/min/g.fw at

maturity, respectively (Hang, 2002).

The DPPH is a stable free radical. Antioxidants,

Figure 3. The fruit as co rbic a ci d (A) and t ota l phe noli c

compound content (B) of A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at

100 DAA and 150 DAA. Columns labelled with different letters

are significantly different from one another for different varieties

(P<0.05).

Figure 4. The fruit POD (A) and PPO (B) activity of A. setosa

¡¥No.9¡¦, ¡¥CH3¡¦ and ¡¥CH4¡¦ at 100 DAA and 150 DAA. Columns

labelled with different letters are significantly different from one

another for different varieties (P<0.05).

222

Botanical Studies, Vol. 49, 2008

when interacting with DPPH, either transfer electrons or

hydrogen atoms to the DPPH radical, thereby neutralizing

it (Naik et al., 2003). Free radical DPPH scavenging

activities were all >90% for A. setosa ¡¥No.9¡¦, ¡¥CH3¡¦

and ¡¥CH4¡¦ at 100 DAA and 150 DAA. The antioxidant

defence system of the body is composed of a mixture of

antioxidants. Fruit are good sources of antioxidants that

may be more effective and economical than supplements

in protecting the body against oxidative damage under

different conditions (Leong and Shui, 2002). Mature

fruit does not have ferrous ion chelating capability. The

radical scavenging and chelating activities are beneficial

antioxidative effects against radical-associated health

problems, such as cancer and coronary heart disease (Yu et

al., 2004).

In summary, the relatively high insect and disease-

resistant characteristics of A. setosa ¡¥No.9¡¦ can be

attributed to the adult plant, leaves, and the length of the

down on the fruit. Anthesis early and matures early for

A. setosa ¡¥No.9¡¦; however, the fruit has a long flat shape.

Fruit fresh weight was 66¡Ó10 g, SSC was 6.2¡Ó0.1 ¢XBrix.

Flesh firmness was 73¡Ó7 N. Ascorbic acid content was 83

¡Ó3 mg/100 g. Total phenolic compound content was 0.4

¡Ó0.1 mg/g, and PPO activity was 0.01¡Ó0.0 .A

420

/min/

g.fw. Thus, A. setosa ¡¥No.9¡¦ has significant potential for

commercial production.

Acknowledgments. The authors would like to thank

the National Science Council of the Republic of China,

Taiwan, for financially supporting this research under

Contract No. NSC92-2313-B-005-081.

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