Bioavailability of starch in various wheat-based bread products: evaluation of metabolic responses in healthy subjects and rate and extent of in vitro starch digestion13 J#{246}rgenHoim

and

ABSTRACt’ were

rate

of in vitro

evaluated starch

bread products two coarse-wheat

HSFB

Also

and

content

the

were

The

higher

released

ofchewed

from

g/100 g starch. a higher satiety

The

tubing

re-

structure

(HSFB), metabolic

those

and re-

to CB and

in metabolic

after

RS content

Am J C/in Nuir

of in vitro

reduction

and the was also

enzyme

ranged

HSFBs and the CB with score than did the WWBs

meal.

wheat

with intact kernels in these products

a dialysis

samples.

per se (4). However,

the

(WWB) products addition, three

than

prominent

prod-

were

fiber content included. The

in general

most

to bread studied

white-wheat-bread and monoglyceride

was noted with the CBs with oat bran. The starch

slowly

bation

test

ratio

responses

subjects.

with a high soluble breads (CB) were

products.

more

insulin

digestion Three

to WWBs

responses HSFBs

and

in healthy

starch (RS). in crust-crumb

sponses

Bj#{246}rck

Glucose

ucts sistant varying

Inger

incu-

from

0 to 1.7

intact kernels immediately

showed after the

1992;55:420-9.

than

WORDS

sistant

White

starch,

responses,

starch

healthy

bread,

digestion subjects,

whole rate,

grains,

soluble

glycemic

and

fiber,

re-

responses to starchy foods vary greatly depending as the botanical origin or the type and extent of (1-8). This is of consequence in the dietary

The glycemic on factors such food processing management betes

of important

(1, 2) and

metabolic

hyperlipidemia

(9).

disorders, The

including

glycemic

dia-

response

and

consequently the insulin demand appear to be closely related to the enzymic susceptibility of starch (10) as well as to the rate of gastric emptying (6). Much work has been done to evaluate mechanisms sorption

behind (3,

5-7,

differences 10) and

on the glycemic response conventional white bread and (1,

absorbed 6,

8,

food

10-14).

that

This

in the

to rank

Bread

makes

starch and dietary or more of the daily both

starchy

of digestion foods

and

by their

abeffect

(1, 2, 4-8). In many of these studies has been identified as a rapidly digested elicits

high

is probably

emptying (6) and to a high rate The high metabolic responses fortunate.

rate

glucose

related

insulin

(4,

12) or barley

may

also

fiber, with

such flour

It constitutes and cannot

part

(3). breads of our

the main easily be

Am

are unintake

of

part of one replaced in

J C/in

lower

glycemic

made

from

be reduced

in bread

ofincorporating the glycemic response

The

by the

addition

of whole metabolic

defined

analytically solubilized

as starch

in alkali baking

heat treatment

variable

of in vitro

of dietary

as well

(21-23)

and has been

amylose

(24,

appears

to resemble

it passes

undigested fermented

25).

shown RS

of soluble

to starch

19),

several

flour eg,

(RS).

in vitro

(18,

as during

types

respect starch

to amylases

Nutritionally,

certain

of wheat components,

with

or dimethylsulfoxide

(18-21)

rye

types

resistant

resistant

or cracked

to bread

of viscous

nutritional

formation

flour.

intact to bread

response

as guar gum ( 16), or by replacement types richer in viscous dietary fiber

is the

milled

the effect

grains.

rye flour (17). Another interesting

physical responses

RS,

unless

is formed

other

types

of

to consist

of retro-

in cereal

products

dietary

through the small intestine in the hind gut (20, 23). To

fiber in that

(20, 2 1 , 23) but a certain extent

delivery of starch to the colon microflora seems to be desirable (26). The amount of RS delivered daily to the large bowel by a Western diet was recently estimated at 2.5-5 g (8), which is considerable.

In view

of the

quantitative

importance

of bread

in our diet, bread can be expected to be one ofthe major sources ofRS. However, the actual amount in a bread product may vary ofvariations

because

The

purpose

improving

in formulas

of the present

the nutritional

and

study

properties

baking

conditions

was to evaluate ofstarch

in bread.

(18,

19).

means

of

Attempts

were also made to explore possible mechanisms for the differences in metabolic responses to white wheat bread reported in the literature.

The

effects

on glycemic

and

insulinemic

responses

gastric

contrast to other rapidly digested base foods, eg, potato. Most results reported concern white wheat bread. Studies with wholemeal wheat bread indicate no effects of dietary fiber in wheat

420

(14)

as in bulgur

as well as the satiety scores for various bread products were evaluated in healthy subjects. In parallel to the clinical studies, starch

responses

to a rapid

of starch digestion to conventional

up a considerable fiber. meals

and

both

concerning

structure

as well as the firm

wheat kernels in bread. However, appears to be lower after incorporation

is easily Introduction

botanical (14)

( 1 5) produce wheat bread

products

are available

intact grains)

does a corresponding

graded

insulinemic

satiety

cracked

ofpasta

No data

during KEY

a more

(parboiled

Nuir

l992;55:420-9.

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/2/420/4715424 by guest on 29 January 2018

I From the Department of Applied Nutrition and Food University of Lund, Lund, Sweden. 2 Supported by grants from the Cerealia Foundation R&D,

Address reprint requests to I Bj#{246}rck, Department and Food Chemistry, Chemical Center, University 124, S-22 1 00 Lund, Sweden. Received December 27, 1990. Accepted for publication July 10, 1991. 3

Printed

in USA.

© 1992 American

Society

Chemistry, Stockholm.

ofApplied Nutrition of Lund, P0 Box

for Clinical

Nutrition

STARCH digestion

rate

system

was

measured

employing

artificially

in the

in a recently

enzyme

incubation

disintegrated

content

products

various

DIGESTION

bread

developed

of chewed in dialysis

products

also

VARIOUS

BREAD

was

strained

off. In another

than

was

brought

to boil

The

RS

determined.

Materials Bread

and methods

White

wheat from

bran

flour,

Nord

whole-grain

Mills

is prepared

wheat,

by steaming

protein,

and

oat bran

8% fat.

The

dehusked

followed by milling and bolting 2 1% dietary fiber (1 3% insoluble 20%

and

AB (Malm#{246}, Sweden).

The

Malm#{246},Sweden)

dietary and

fiber 31%

(36.3%

spaghetti

whole

used

contained

insoluble

and

wheat

(WWB-tl)

and

erides

All WWBs

were

(WWB-r).

flour, 200 g baker’s yeast, mg, 37 g monoglycerides

contained

7.4%

(WWB-r)

and

ing for 35 mm

Two

without

baked

from

they pouches

as rolls

#{176}C, 75%

of coarse

bread

composed

wheat

flour

(20%)

posed

of 70%

relative

then cooled. 1200 g water as with

(CB-wwg)

The

was

3700

except

doughs

that

by a second

humidity).

Baking

divided

to 45 mm

were performed was extended of 550

g and

variants

that

contained

HSFB-ob oat bran,

40 g yeast,

kernels white

wheat and

whole-grain

proofing

into

pieces

baking

time

breads

increased rich

according and

3300

to the following g water

were

baking

ac-

recipe:

mixed

and

fiber

bread blend 1665 g

the dough

1 85 g wheat

300

were

g water

and

Kristianstad,

Sweden), to that

proportion

discarded),

and

of starch

bags

milled

and

is shown

was

The

in Table

(30) with

in the product

com-

1.

for volume

determined

(measured

and

used

lipids.

to es-

The

divided starch

is free oflipids starch,

of crust

amounted

by BV for (St#{228}rkelsen,

and with

to 37

frac-

as BV

an amylose

was used as lipid-free

ofwheat

by

value (BV), (lipid-free)

was calculated

product potato

and (29).

by polarized

granules.

complexed

bread

total

HSFB-ob)

examined

starch

(< 0.8

The (27),

(only

were the

which

were

plastic

analysis.

3-glucans

of amylose

content close reference.

were

oven

also analyzed

amylose

pro-

was put in a 16 h. Subse-

proportion ofcrust. The blue to the amount ofuncomplexed

in starch,

fraction

ofcomplexed

starch

± 3% (wt:wt,

dry

basis, n = 3) in WWB-r, which was higher than the proportion in the corresponding white loafs (WWB-mg and WWB-tl) (24 ± 2%, n = 3). Addition of monoglycerides increased the bread volume of white loafs by 10%. The specific volumes were 3.4 and

3.8 cm3/g

for WWB-tl

the crumb was monoglycerides. was

only

two

other

much The

slightly

croscope

(data

and

softer fraction

higher

WWBs

in the appearance different bread

flour, added.

Rate

ofin

The

WWB-mg,

and more ofamylose

in WWB-mg

(46.0

± 1.2)

(n

=

respectively.

Further,

porous after complexed

(50.0

± 1.4%)

5). No

striking

addition of with lipids than

in the

differences

of starch granules were observed when products were examined with polarization not

the mi-

shown).

bating

the

Chemical,

cubations

the decoction

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/2/420/4715424 by guest on 29 January 2018

vitro starch

digestion

boil to extract

and

and

the

substrate)

(ends

contents

products

were

present the

otherwise

bread for

before

of samples

bread

acid, in Table

characterization

to characterize

products

amylose

with

components

(28),

ascorbic

foil and

in a vacuum for

suspensions of the

Proofing and baking were performed as with WWB-tl except that doughs were divided into pieces of 550 g and baking time was increased to 25 mm. HSFB-ls was baked according to the following recipe: 500 g linseed in 3000 g water was brought to water-soluble-fiber

fiber

In

contained

are shown

(as yeast

slices

Sweden)

analyzed

sources

g water.

(HSFB-mf).

wheat

and

first into

dietary

1850 g white

170 g yeast,

dried

Tecator,

microscopy

The to

to 25 mm.

was left to rest for 16 h. To this dough gluten,

and

was baked

ingredients

and physical

seed replacement) which is proportional

performed

oat bran bread (HSFB-ob), linseed product baked from a commercial of high-fiber

into

for lipid-free starch minus BV for lipid-free starch. Pure commercial

increased

in soluble

cut

corn-

(CB-sp).

WWB-tl except that the The doughs were divided was

50 g sucrose

was

commercial fiber

mixture

After cooling each at room temperature

were

were

position

g yeast WWB-

2000

to 27 mm;

bread

of 580 g and

#{176}C. CB-sp

products

dietary

light

and 200 as with

WWB-tl.

tion

200 g yeast, were

and

analysis

products

g of the

ie, amylase,

white

flour

was

as with

bread

and

in the mixture

was extended

same

Cyclotec,

timate

recipe: 2960 g for 20 mm and

flour, baking

The

g water

1 500

various

the

for rolls, and put in aluminium at -20 #{176}C until used.

Chemical

in 1500

batch

and

improvers,

and

(80%)

wheat

first

at 200

as with to 30 mm.

a mixture

was baked

baked:

flour

ingredients

ingredients

NaC1

the

except stored

this

100 g yeast,

fiber

in all recipes. bag and stored

WWB

per-

and

time the

grams

quently,

proofwas

recipe: 2600 g cuts of spaghetti (1-1.5 g water for 30 mm. Subsequently, 1 100 200 g yeast were added. Proofing and

ofhigh-fiber

(HSFB) were baked: (HSFB-Is), and one

were

was

Aqueous

44060-g

(20 mm for rolls) the first 30 s.

to the following in 2960 g water

the

into into

baking

Fifty

AB),

of baking

1 . The

included plastic

wheat

Mills

The

cedure

soluble

In the case of WWBdoughs were proofed

an experimental 30%

g white Proofing

were

increased

and

wheat

g white

types

cysteine.

mm;

monoglyc-

were divided or divided

wheat

according were boiled

cording to the following cm) were soaked in 2000 g white wheat flour and

Three

protein,

followed

(CB)

and

cuts

To this 740 were added.

WWB-tl

mm.

bread of intact

spaghetti

CB-wwg was baked whole-wheat grains

pieces

43.7%

24%

added

and 2000 g water. were added. The

formed

(38

variants

baking proofing

basis)

soluble),

formed at 2 10 #{176}C (200 #{176}C for rolls) for 22 mm in a convection oven with steam added during

30

exclu-

(Storhush#{226}lls Linseeds (AB R

(dry weight

rolls

for 20 mm at 28 #{176}C. Subsequently, g pieces and put in aluminium

time

grains

bread (WWB) were baked: loafs (WWB-mg) and without added

monoglycerides

wheat

oat

white

to flour

several and

fat.

Three variants ofwhite with added monoglycerides

pieces

ob-

and contains (wt/dry wt basis) and 8% soluble), 47% starch,

sively durum wheat with added monoglycerides spagetti, Kungs#{246}rnen AB, J#{228}rna,Sweden).

Lundberg,

were

commercial

g linseed

To

baking time was extended to 30 mm. for HSFB-mfconsisted of3450 g ofa Nord

addition

925

cooled.

2775 g white wheat flour, and baking were performed

containing

(Fiberform,

products

tamed oat

mixture

batch

and

decoction oflinseed, were added. Proofing tl except that The formula

421

TYPES

in vitro rather

tubings.

was

IN

rate

digestion of milled

samples

samples

with

St Louis)

with and without

pepsin

at pH

porcine

1 .5 (3 1). The

was

measured

pancreatic

a prior

60-mm

a-amylase

starch (1.8 U/mL sample suspension; mg maltose from soluble starch in 3 mm at pH

were

withdrawn

for determination

before

and after

of reducing

(Sigma

incubation

concentration

200 U/g Samples

by incu-

ct-amylase

15- and sugar

was

1U liberates 1 6.9 and 20 #{176}C).

120-mm

content.

The

inex-

422

HOLM

TABLE

AND

BJRCK

1 and composition

Ingredients

of the breads

based

on dry and wet (values

in brackets) Dietary

Product

White

fibert

Soluble

Protein

g/lOOg

g/lOOg

g/IOOg

79.7 [49.7]

3.5 [2.2]

1.1 [0.71

10.6 [6.6]

2.2 [1.4]

1637 [1022]

-

[38]

80.3 79.9

[49.7] [56.7]

3.7 [2.3] 3.7 [2.6]

1.1 [0.7] 1.1 10.8]

10.7 [6.6] 10.6 [7.5]

1.1 [0.7] 1.1 [0.8]

1604 [992] 1595 [1 135]

-

[38]

-

[29]

69.6

[34.4]

1 1.4 [5.6]

1.2 [0.6]

1 1.7 [5.8]

2.4

[1.2]

1491

[737]

-

[51]

1.2 [0.7]

12.8

1.1 [0.7]

1566

[971]

-

[38]

4.2 [2.2]

1558 [808]

-

[48]

Ingredients

wheat

weights6

Starch

Total

g/IOOg

Fat

Energy

g/lOOg

Water

ki

g/IOOg

breads

WWB-mg

White wheat flour: monoglycerides, White wheat flour White wheat flour

WWB.tl WWB-r Coarse breads CB-wwg

White

wheat

wheat

CB-sp

White

High-soluble-fiber breads HSFB-ob

flour

grains, wheat

cuts,

99:1

whole

20:80

flour

spaghetti

76.0

[47.1]

flour

oat bran:

61.4

[31.8]

10.9 [5.7]t

4.6 [2.4]

19.7 [10.2]

58.8 [33.6]

13.5 [7.7]

3.9 [2.2]

i5.1

[8.6]

10.0 [5.7]

1658 [946]

-

[43]

58.8 [37.4]

15.1 [9.6]

3.4 [2.2]

14.2 [9.0]

7.1 [4.5]

1528 [971]

-

[36]

4.0

[2.5]

[7.9]

30:70

White

wheat

gluten, 50:45:5

HSFB-ls

White wheat flour linseed, 75:25 White wheat flour, linseed, beet fiber, soybean pieces, maize

HSFB-mf

fiber,

pea

seeds,

fiber,

gluten,

cysteine,

sunflower oil,

lecithin,

amylase,

ascorbic

acid 6

Values

for protein,

fat,

t Dietary fiber figures t fl-glucans made up

tent

42%

ofa-amylolysis

to maltose.

the extent

of hydrolysis with

The digestion ucts ylase

within

tamed

of the total

calculated

from

after

dietary

fiber

as the proportion

index

120 mm after

with

120

were

used

The samples

on consecutive

days.

with tap water

and subsequently

times

experiments).

in some

The

respect

They

chewed

were told the

immediately.

prod-

were

told

the product

to rinse

products

were

containing 50 mg pepsin FRG) in 6 mL 0.05 mol

buffer/L (containing mol HC1/L. Finally,

0.4 g NaCI/L) adjusted the subjects rinsed their

part

their

conmouths

15 times then

After mol

to 1.5 with

at 37

the peptic NaOH/L,

(Sigma

#{176}C for

digestion and

Chemical)

transferred 45 mm).

to a dialysis The bag was and

then

then

diluted

suspension

was

diluted

placed

2 mol mm

HC1/L.

with

to pH mouths

Each

mixing

porcine

containing to 30 mL

tubing turned into

(13-cm around a beaker

phate buffer at 37 #{176}C and gently dialysate were taken every 30 mm

with

(30

expecto-

(2000 FIP-U/g, Na,K-phosphate 1 .5 with 2 with 5 mL was and

sample

every

the pH was readjusted

1 mL

mixture

dients

30

of

order

phosphate buffer (pH 6.9) for 60 s and the rinsing solution also transferred into the beaker. The contents were stirred incubated

analyses

of the

breads.

reducing-sugar

was mm. to 6.9 with 2

pancreatic

Iysis

values

hydrolysis individual.

(30-180

values

Resistant

A standard

curve

was

prepared

by

mm)

for the

product

for the WWB-mg

divided

product

by the

chewed

sum

of

by the same

RS, ie, starch that is resistant to amylases in vitro unless solubilized in KOH, was determined as previously described (20). An amount of the dietary fiber residue obtained from the enzyrnatic gravimetric fiber analysis (28) was incubated with amyloglucosidase

KOH/L content

solubilization

prior

Glucose

and insulin

A group

12-15-mm

and

were

2, width the ingre-

mL phosagitated. Samples (2 ml) of up to 3 h and were analyzed 800

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/2/420/4715424 by guest on 29 January 2018

KOH

of three

in the morning intervals of 4-8

The

strips Spectrapor 10 times to mix

y and blood

and

without

in KOH

without

phosphate

buffer

with

prior

solubilization

in 2 mol

for 30 mm. Liberated glucose was quantified and starch was calculated as 0.9 X monomer weight. RS was exas the amount of starch available to amyloglucosidase

pressed after

10th

a-amylase

starch

1 10 U was added.

containing

content.

using maltose. The extent of hydrolysis was calculated as 100 x mg maltose equivalents X 0.95 mg starch in sample. An hydrolysis index was calculated as 100 times the sum of hydro-

not to eat

central

All portions

rated into a beaker Merck, Darmstadt,

pH was adjusted

on

-

a-am(15).

in a randomized

chew The

as

to the extent

with added procedure

from

were given

subjects

expressed

mm.

Samples

cut offand

1 g starch.

for

(%) of starch

was

by using

in the study.

experiment.

are based

content.

with pepsin and subsequently tubing, by a recently developed

participated

tables. All other values

food

starch.

A digestion-rate

WWG-mg

1 h of the

the crumb

are

for resistant

rate was also measured

incubated in dialysis

Six subjects

energy

was calculated

degraded of hydrolysis

and

corrected

the amount

responses men

in healthy

and seven

period.

ofstarch

available

The

34-44 for women,

age

and

y and

subjects

women

after a I 2-h overnight d. They were asked

in the ranges 17.5-23.0

minus

treatment.

body

18.5-23.5

respectively.

ate their

test meals

fast in random to eat the breakfast mass

index

for men

order at over a

(in

kg/rn2)

and

26-49

Finger-prick capillary the meal and at 30, 45, 70,

samples were obtained before 120, and 180 mm after the start of the meal for analysis of glucose and at 30, 45, 95, and 120 mm for analysis of insulin. Blood glucose concentration was determined with a glucose 95,

STARCH TABLE 2 Composition

DIGESTION

IN

VARIOUS

BREAD

TYPES

423

of the break fast test meals Dicta ry fiber Bread

WWB-mg WWB-tl

Cheese

Coffee or tea6

Margarine

g

g

g

g

101 101

32 32

6 7

220 220

Starch

Total

g

Soluble

Protein

Fat

Energy

g

g

g

g

kJ

50 50

2.2 2.3

0.7 0.7

15.9 15.9

15.5 15.6

1733 1738

WWB-r

88

32

7

235

50

2.3

0.7

15.9

15.6

1738

CB-wwg CB-sp HSFB-ob HSFB-ls HSFB-mf

145 106 157 149 134

26 26

8 9

185 220

SOt SOf

8.1 2.6

0.9 0.7

15.9 15.9

15.6 15.4

1738 1729

15

185

50

9.1

3.9

16.0

15.5

1738

4 7

195 210

50 50

11.5 12.9

3.3 3.0

15.7 16.1

14.6 15.7

1696 1746

6

Various

10 14

amounts

t 39 g originates

f

-

were given from from

35 g originates

because

of differences

oxidase peroxidase with an enzyme

reagent and immunoassay

plasma insulin kit (Boehringer

Mannheim,

The

index

FRG).

the 2-h incremental food (GI = 100)

glycemic

or lipids are added products. Also,

naturally

occurring

were

in the

similarly

WWB-mg ethics

lipids

or added

present

culated

(GI)

was

calculated

(HSFB-ob,

spaghetti).

HSFB-ls),

as reference. of the

meals bread

composition

response

index

of the study

University

of Lund,

lipids

margarine, water

contents

test

50 g starch were served

and

coffee of the

content

was 260 g for all breakfast

(three with

and

tea

test

meals

to balance

performed

with

the

All

breads

ceptability from

all subjects

by others. acceptability

was given

by the

except scores

cal-

WWB-r (Table

and

showed

very much Addition

and

and

satiety after

received

subjects

average tended

by increasing

resents

like

estimated

extremely.

numerically

3). However,

slices of bread). The amounts of cheese,

TABLE

3

the

Acceptability

fat,

and

finishing -4

the

breakfast,

ofthe

bread

the

subjects

Statistical

products

on a bipolar

represents dislike extremely, neither like or dislike, and

The

satiety

according

score

to Haber

extreme

of the

test

et al (33).

0 rep+4 repmeals

was

Assessments

satiety.

the

satiety

and satiety

otherwise stated. (bread product,

Results type of

bread, and subject were chosen as factors) and multiple comparisons were made by using least significant difference (LSD). The Wilcoxon signed-ranks test was also used to test significance between (WWB-mg)

softness

the of the

a higher satiating effect cornafter the meal was finished scores

for HSFBs

for the different

scores

Acceptability scoret

the white and each

wheat other

WWB-mg

bread with added product. Statistical

monoeval-

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/2/420/4715424 by guest on 29 January 2018

1.3 ± 04d 0.6 ± 0.5k

WWB-tl

WWB-r CB-wwg

0.8±0.7c

CB-sp

-0.3

± 06gb

HSFB-Ob

2502d

HSFB-ls HSFB-mf

1.5 ± 0.3” 1.7 ± 0.4

6

evaluation

Results are given as means ± SE ifnot were subjected to analysis of variance

ofdifferences glycerides

to increase the

and

CB-wwg

bread

products6

15 mm

wore

95 mm

180 mm

were

were done before the meal and at 15 (immediately after finishing the meal), 95, and 180 mm after the start of the meal on a scoring system graded from - 10, to represent extreme hunger, to + 10, to represent

CB-wwg

moderately

2. All

scores

scale (32) where a neutral response

acratings

score.

and disliked

of monoglycerides loaves

positive positive

meals.

asked to assess the acceptability hedonic resents

(SPSS

crumb.

Product Immediately

program

received

the highest

by some

of WWB

(Table in Table

CB-sp

3). HSFB-ob

All HSFBs and CB-wwg showed pared with WWB-mg immediately

protein,

SPSS/PC+

Results

(1 1) with

Sweden.

is shown

to four different

were

Satiety Acceptability

meals.

Chicago).

was liked

was

curves

Approval

whiteeither

monoglycerides

insulinemic

insulin

of the

contained products

The total water

from

added

(CB-sp;

The

the

Inc,

Test meals The

of the breads.

uations

as the reference because mono-

to most commercially baked all test products contained

monoglycerides

from

committee

content

concentration Mannheim,

glucose area using WWB-mg ( 1 3). WWB-mg was chosen

glycerides wheat-bread

(HSFB-mf),

in water

whole-wheat grains. spaghetti cuts.

3.6 ± 0.4k

0.9

± 0.9

-3.8

± 0.7

3.7 ± 0.Sa

1.2 ± 0.8

-3.6

± 0.6

4.0±0.3w

1.1 ±0.8

-3.6±

5#{149}20#{149}4b

2.1±0.7

-3.0±0.8

4.0 ± #{216}5C

1.0 ± 0.8

-3.4

45#{216}5abc

1.8±0.8

-2.3±0.9

2.2 2.3

-3.4

± 0.6

-2.6

± 0.7

5.0 ± 0.4 5.1

±

0.2*

± 0.6 ± 0.6*

1.1 ± 1.1

SE.

t Means not sharing the same superscript letter are ferent according to analysis ofvariance (LSD): P < 0.01 r vs WWB-tl, WWB-r vs CB-wwg, WWB-mg vs CB-sp CB-wwg (P < 0.05). Means not sharing the same superscript letter are ferent according to analysis ofvariance (LSD): P < 0.05 mg vs CB-wwg (P < 0.01). No significant differences 95 and 180 mm. § Significantly different from WWB-mg reference P < signed-rank test).

significantly difexcept for WWBand HSFB-ob vs significantly difexcept for WWBwere observed at 0.05 (Wilcoxon’s

424

HOLM

did

not

mm

with

remain

The

significantly

the

WWBs

at 95

and

of starch

bation

with

pepsin

bread

products.

of hydrolysis quently,

and

were

the

with

a-amylase

1 5 and 39-43%

hydrolysis

milled were

120 mm and

indexes

samples

similar

for

a-amylolysis

7 1-75%,

eight

bread

products,

close

to

glucose

was extended

incubation,

the

difference

from

WWBs

was

15 to 30 times.

were

observed

After

completely

is equivalent

between

the

two

white

of chewed

or partially

CB-wwg

disintegrated

resulted

in a mixture

pepsin in that

with

intact

kernels.

RS was detected in all bread products except in HSFB-mf (Table 5). Only traces of RS (< 0.1% dry weight basis) were detected

ofRS

in fiber

was highest

glycerides

residues

(WWB-mg)

decrease

the

RS

from

in CB-wwg.

the

or baking

content

raw

Ofthe

materials.

WWBs, as rolls

compared

with

The

addition

content

of mono-

(WWB-r)

tended

that

to

in

observed

WWB-tl.

TABLE In vitro

4 starch

digestion

rate,

area under

glucose-

and insulin

graph,

(180

responses

response

Product

hy drolysis

Milled6

and glycemic

and insulinemic

Glucose area

Chewedt

mmo/#{149} L’

%

WWB-mg WWB-tl

100 102

WWB-r

104

CB-wwg

105

CB-sp

102

nd

HSFB-ob

103

86 ± lI’

HSFB-ls

103

nd

HSFB-mf

100

nd

Milled

(< 0.8 mm)

100’ 96

±

re-

than

not significant. lower glucose

In the values

compared

with

HSFB-ob

and

WWB-mg.

HSFB-mf

The

were

to be

lower

after

WWB-tl

than

sig-

after

indexes

of the bread

products

variables

79

±

nmol

.

L’

.

min’

%

%

18.6

20.0 ± 2.8 16.6 ± 2.8

84

18.7

19.0±2.9

96±

11ab

80.4 ± 12.011

14.3 ± 3.811

68 ±

911b

93.2 ± 13.311

15.6 ± 2.611

79 ± 9b

13.611 1 16.6 ± 24.5 90.3 ± 12.6)1

12.9 ± 2.711 14.7 ± 2.511 15.5 ± 2.4

75 ± 9II’’ 93 ± l5’’

67 ±

78 ± 711ab

89 ± 15”J

89.8

digestion

min’

Insulinemic indext

14.8

112.7±

peptic-amylolytic

.

Glycemic mndext

±

98.7

4(1b

Insulin area

±

122.2

4’

nd

before

initial

WWB-tl

index

%

6

mm)

after

tended

Metabolic In vitro

after

(Fig 3, top) and the difference was statistically significant after 45 mm (P < 0.05 by Wilcoxon test). The response to CB-wwg was significantly lower at all times except at 30 mm (Fig 3, middle). All HSFBs showed significantly lower insulin concentrations than did WWB-mg after 45 and 95 mm (Fig 3, bottom). The GI was significantly lower after CB-wwg than after WWBmg (P < 0.05 by LSD and Wilcoxon tests) (Table 4). The GIs of HSFB-ob and HSFB-mf were also lower than that of WWBmg according to the Wilcoxon test (P < 0.05). The GI group mean for CBs was lower than that ofWWBs (P < 0.05 by LSD). The insulinemic indexes of CB-wwg and HSFB-ob were significantly lower than those ofWWB-mg and WWB-r (P < 0.05 for all four differences by both LSD and Wilcoxon tests). The insulinemic indexes of CB-sp and HSFB-ls were also lower than that of WWB-mg according to the Wilcoxon test. The insulinemic index group means for CBs and HSFBs were significantly lower than that ofWWBs (P < 0.01 and P < 0.05, respectively, by LSD). A statistical evaluation based on the areas under the

WWB-mg disintegrated more rapidly and a very fine milky suspension was obtained. Microscopic examination showed a suspension of free swollen starch granules. In contrast peptic incubation

to be lower

WWB-mg

A small

loaves

glucose

insulin

tested

30-mm

disintegrated.

tended

did not differ the

nificantly lower than after WWB-mg whereas HSFB-ls showed a response similar to that obtained with WWB-mg at all times (Fig 2, bottom). Apart from the response to HSFB-ls, the insulin responses were closely associated with the glucose responses (Fig 3). The

HSFB products used in the experiment (CB-wwg and HSFB-ob) showed significantly lower digestion rates. No changes in the degrees of hydrolysis were observed with WWB-mg and CB-wwg when chewing

concentration

initial

to a decrease of 1 5%. After 120 mm the corresponding figures were 73 ± 2% and 71 ± 2%, respectively. The digestion rate for chewed products subjected to a-amylolysis in dialysis bags was highest with the two WWBs (WWB-mg and WWB-tl) (Fig 1, Table 4). The CB and

(30 and 45 mm)

WWBs

However,

than did the WWB-mg reference (Fig 2, middle). CB-sp showed a very slow decline, which resulted in a significantly higher late

Conse-

were

which

2, top).

after WWB-mg but the differences were initial phase both CBs showed significantly

eight

degrees

(Table 4). When the peptic-digestion step the initial degree of hydrolysis (15 mm) decreased magnitude with all samples, on average from 41

± 2% to 35 ± 2% for the

to the three

(Fig

the the

samples

responses point

sponse

respectively.

for milled

at any

on incu-

for all products

was omitted, by the same

glucose

significantly

hydrolysis

After

BJORCK The blood

180

a few exceptions.

rates

100

above

AND

±

in a beaker.

Mean

of two experiments.

100’

The coefficient

±

100’

12*L

88

±

9ab

103± 12’ 69 ± 8II’

J

of variation

78

± 6IIb

911”

‘

77 ± 811ab }

did not exceed

6*

2.3%

for any product.

t Chewed before peptic-amylolytic digestion in a dialysis sac. Mean ofsix experiments. Means not sharing the same superscript letter are significantly different by analysis of variance (LSD): P < 0.001 except for WWB-mg vs HSFB-Ob (P < 0.01) and WWB-tl vs HSFB-ob (P < 0.05). f Means not sharing the same superscript letter are significantly different according to analysis of variance (LSD): P < 0.05. § I ± SE. II Significantly different from WWB-mg reference by Wilcoxon’s signed-rank test: P < 0.05. #{182} Group mean for CBs significantly different from group mean for WWBs by analysis of variance (LSD): P < 0.05 (glycemic (insulinemic index). 66 Group mean for HSFBs significantly different from group mean for WWBs by analysis of variance (LSD): P < 0.05.

Downloaded from https://academic.oup.com/ajcn/article-abstract/55/2/420/4715424 by guest on 29 January 2018

index),

P