ika dan ipa di produk

8/8/2019 Ika Dan Ipa Di Produk

http://slidepdf.com/reader/full/ika-dan-ipa-di-produk 1/5

Water Absorption and Solubility and Amylograph Characteristics

of Roll-Cooked Small Grain Products!

R. A. ANDERSON, Northern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture,Peoria, IL 61604

ABSTRACT Cereal Chern. 59(4): 265-269

For many years, cereals and cereal products have been gelatinized or

cooked on hea ted rolls to prepare special ty products. Corn and grain

sorghum grits or flours have been the raw materials used most frequently.

Examination of the roll cooking of several other cereal derivatives (ie, gritsfrom wheat, barley, rye, and oats) has shownthat rheological characteristics

d if fe r when the var ious products are processed under like conditions.

Comparisons made ofwaterabsorption (WAI), watersolubility (WSI), and

Brabender amylograph patterns ofthe resultingproducts revealed not only

Gas- or s team-hea ted rolls have been used for many years to

prepare partially or completely gelatinized starches. flours, and

meals (Powell 1967, Whistler 1970). The degree of cooking of the

product generally depends on moisture content , par ticle size,

temperature, roll pressure, and duration of heating. By varying the

operating parameters, cooked products can be made that exhibit a

range of rheological properties. Products may bealtered to provide

materials with different water absorption and solubilities and with

different viscosity properties, as shown by Brabender amylographpatterns. We studied the roll cooking of corn and grain sorghum

grits (Anderson et al 1969a. 1969b, 1970) and include in this work

similar studies on grits prepared from wheat, barley, rye, and oats.

MATERIALS AND METHODS

MaterialsBarley, rye, hard wheat, and oats were obt ai ned through

commercial channels. Grits were prepared from barley, rye, and

wheat by passing each grain several times through an abrasive

dehulling machine to remove the bran, aspirating to recover bran,

and then reducing the dehulled grains on a roller mill to obtain grits

that would pass a no. 12 screen. Oats were dehul led in a scourer ,

aspirated, and then milled in a coffee mill to make grits that would

pass a no. 12 screen. Chemical analyses of these materials, and o f

corn and grain sorghum are shown in Table I.

Equipment and Experimental MethodsFo r these tests, the GF pilot-plant gas-fired roll drier having a

I Presented at the Annual Meeting of the American Association of Cereal Chemists.

October ~ 5 - 2 9 , 1981, Denver. CO.

Mention of firm names or trade products does not imply that they areendorsed or

recommended by the U.S. Department of Agricul ture over other f irms or similar

products not mentioned.

This a rt ic le is i n t he p Ub li c d om ai n an d not copyrightable. It may be freelyreprinted with customary crediting of the source. TheAmerican Association of

Cereal Chemists, Inc., 1982.

many similarit ies between the different cereals but also some interesting

differences. Cooked grits from oats had considerably lower WAI and WSI

values than the other grains under study; the WAI peaked about 100° F

(37° C) lower than that ofgrits from wheat, barley, rye, corn. and sorghum.Oat products gave amylograph patterns similar to those of corn, sorghum,

and wheat, whereas cooked barley grits gave atypical viscosity patterns,

with elevated values at all critical points.

12-in. diameter (General Food Package Equipment Co .. Benton

Harbor, MI) was used. Grits from the various grains were cooked

on the gas-fired' drier at temperatures ranging from 250 to 570 0 F

(121-299°C) and a t moisture levels of 15 and 25%. Roll clearance

was set cold at 0.00I in. (0.025 mm), and roll speed was 3 rpm.

Analytical MethodsRolled-cooked grit products were evaluated by measuring their

water-absorption index (WAI), water-solubilitv index (WSI), andBrabender viscosity patterns. .

The water-absorption index is the weight of gel obtained per

gram of dry sample through a modif icat ion of the method

descr ibed by Kite et al (1957) for measur ing swelling power of

starch. A 2.5-g sample of ground product «60 mesh) was

suspended in 3ml of water at 30°C in a 50-ml tared centrifuge tube,

stirred intermittently for 30 min, and centrifuged at 3,000 Xg for IO

min. The supernatant li qu id was poured careful ly in to a tar ed

evaporating dish. The remaining gel was weighed and the WAI

calculated from its weight.

As an index of water solubility, the amount o f dried solids

r ecovered by evaporating the supernatant from the water

absorption test was expressed as percentage of dry solids in the

2.5-g sample.

The amylograph tes t was done in the standard manner, with 500

g of 9% (db) suspension of the sample «60 mesh), heated from 29

to 95° C in44 min, held at 95° C for 16 min. and thencooled to 50° C

in 30 min.

Chemical analyses of the grains and their grit products were

conducted according to AACC methods (1962). Moisture was

determined in a Brabender moisture tester.

RESULTS AND DISCUSSION

Only two of the operating factors were varied du ring the

experimental work: the moisture content of the gri ts and the roll

surface temperature. The other operating conditions, such as roll

pressure, duration of heating, and particle size of the grits, were

Vol. 59, No.4, 1982 265



TABLE IChemical Analysis of Whole Grain and Prepared Grits Used in Cooking Experiments

Wheat Barley

Grain Grits Grain Grits

Moisture, % 12.7 12.2 10.9 12.0Nitrogen, % 2.4 2.2 1.5 1.4Crude fat, % 1.4 0.9 1.6 0.9Crude fiber, % l.7 0.8 4.7 0.6Ash, % 1.6 1.1 2.4 1.I

Rye OatsGrain

Corn Sorghum

Grain Grits Grain Grits Grits Grits

11.8 11.9 9.9 10.0 14.0 12.0

1.8 1.5 1.9 2.6 1.3 1.5

1.5 0.6 4.9 6.7 0.5 0.81.8 0.6 10.6 1.2 0.3l.7 1.3 3.1 l.7 0.4 0.3

265'F1129'CI

\ ~ / ? ~ 0 0 ' F I 2 0 4 ' C I

y

/\I \I \

I \I ' -

/ /

_ /

---

200

500

100

500

100

400

'""'".g 30005

;§ 400

'E:::l

j 300

e<Xl 200

560'FI294'CI

_L-----..- - - - - -ot:=:=r=::::::i:=:::::C::L------L_.l.-----l----I.._.l.---lo 10 20 30 40 50 60 70 80 90

Minutes

1---- Heat • I Hold· I Coo l - - - 1

29'C 95'C 95'C 50'C

Fig. 3. Roll cooking of wheatgrits: Effect of temperature on viscosity (25moisture).

265'F1129'CI

\/

/{/ 450'FI232'C)

/___// 550'F1288'CI

YI

~ .~

/ : , . . - - - - - - - - // o ~ s : = S ~ - ~ _ L _ _ _ _ L _ _L__.L_L..__L_.J

o 10 20 30 40 50 60 70 80 90

Minutes

t----Heat .. I Hold .. I Cool- l

29'C 95'C 95'C 50'C

Fig, 2, Roll cooking wheat grits: Effect of temperature on viscosity (15moisture).

600 r-------------------------,

600r - - - - - - - - - - - - - - - - - - - - ,

tvI

III

25% MOisture/ •

o ..... ° :P/-.......;; ......... ~ /-

-.. _ . ; : ~ ..

. -......--- . 15% Moisture

25%0Moisture_ ' __ .

, , " " - 0---0_O, ......._/' _-.0/ 15% Moisture

o /

...............

14

:= 12tr.l

><Q)

-g 10

.:.c:::::s 8ctr.l.

Ci>

C;;6

:

4

8

e:t:s:>< 6)

'"Cc::

c::.S: 4-ec

'"ce:t:.... 2)

-"s:0

400 DF(204 DC)

TemperatureFig. 1. Roll cooking of wheat grits: Effect of temperature and moisture on

water-absorption index (WAI) and water-solubility index (WSI).

constant throughout the study.In Figs. 1-3, results are given for the roll processing of wheat

grits. Peak WAI appears to be about 6, occurring at 25% moistureand 400°F (204°C); this peak was not reached with the 15%

moisture sample. The WAI of the 15% sample leveled off at thehigher temperatures because starch degradation was occurring,evidenced by toasting and by the viscosity patterns (Figs. 2 and 3).The WSI decreased slightly as temperature was increased at both

moisture levels to 400-425°F (204-218°C), then rose rather

rapidly. Characteristic viscosity patterns were obtained, with initialpaste viscosity (29°C) increasingwith an increase in temperature ofroll cooking, and the final cooked paste viscosity (50°C)

decreasing. Degradation occurred in both the 15 and 25% moistures'amples that were roll cooked at 550° F (288° C), as evidenced by

lower peak and final cooked paste viscosities. At maximum WAI,peak viscosity was 280 Brabender units (BU) at 15% moisture and450°F (232° C) and 480 BU at 25% moisture and 400° F (204° C).Figures 4-6 show the results obtained from the roll cooking of

barley grits. As shown in Fig. 4, the WAI follows a typical curveboth moisture levels. In the 25% moisture sample, the maximu

WAI of 8 is reached at about 425° F (218°C), after whichdecreases. At 15% moisture, WAI never reaches the maximumpeaking at about 7 at 460° F (238°C) and then falling off. The W

remains level at 5until about 425°F (218°C) and then progressiveincreases, with the 25% moisture sample increasing at a slightgreater rate.

Figure 5showsviscositycurves for barleygrits processed at 15moisture at three different temperatures. The initial paste viscosi

(29°C) increases as temperature of roll cooking increases; this alsoccurs with the 25% moisture samples (Fig. 6). Viscosity peaks

maximum WAI occurred at 460°F (238°C) for 15% moistusample and at 410° F (2100 C) for the 25% moisture sample. Theviscosity peaks are the highest we have seen for any of the grainstudied, varying from about 1,500 BU for the 15% moisture sampat 460°F (238°C) to 1,800 BU for the 25% moisture sample410°F (210°C). Final cooked paste viscosities (50°C) decreasecharacteristically as the roll cooking temperatures were increase

266 CEREAL CHEMISTRY



41 O'FI21 O'CI

\ //

\ // 550'FI2SS'CI.... . / ../

' - -.../, ../

.../ ........_---------__ -_ - --

O l . .- - . . .L - - - - - - - I - - - - . . . .L - - - - - - I

6

o 25% Moisture

, ~ " " " ' ' ' ' ' ' ' ' ' - ' ' 0 ..0/ ...........

/ 0 ~ /

4 / /o

fill

2-- - - '

6L--...L------l.----...L------.-4

8

300

1200

XQJ

"1:lc:

2000 r - - - - - - - - - - - - - - - - - - -

lS00

14 , . - - - - - - - - - - - - - ~

1500

10

J ~ ~ 1 5 % Moisture V80__~ ~ ~ . '

2= .... - = - ~ " 025% Moisture

oL----I_--l._-L_-L_..l-_.L-_L----l_--L_....Jo 10 20 30 40 50 60 70 80 90

Minutes

f - - - - - Heat • 1 Hold • 1 Coo l - - - J

29'C 95'C 95'C 50'C

Fig. 6. Roll cooking barley grits: Effect of temperature on viscosity (25%

moisture).

12 0

- II:l

3: /10

QJ /1:l

-= /G

8:E 25% Moisture/:::s 0C 7CI:l

,1fiJ •Q; 6 15% MOistureca ~ - ~ ~ ~ ~ - - - ~ . - -:

4

8 25% Moisture _0= .....

« / . " , . . . s .; 0

6 / '0QJ

0 / ~ 1:l

-=c:Q

4:Es'"..0

«2

Q;cas

0

As with wheat, some starch degradation occurred with samples thatwere roll cooked at 550° F (288° C), as shown by lower peak and

final cooked paste viscosity for both tempering treatments.

Results of the processing of rye grits are given in Figs. 7-9. TheWAI and WSI obtained from these studies gave patterns similar to

those obtained from wheat grits, except at a slightly higher level(Fig. 7). Peak WAI was about 7and, as with wheat, a similar dip in

WSI appeared. Charact eris tic viscosity pa tte rn s again were

obtained from the products of roll-cooked rye grits. Peak

viscosities at maximum WAI were higher than wheat bu t lowerthan barley. These peaks occurred at 450 BU for the 15%,450°F

(232° C) sample and at 990 BU for the 25%,405° F (207° C)sample.

Starch degradation occurs at 550°F (288° C) in both samples.The WAI for cooked oats does not follow the usual pattern

observed with the other cereals tested (Fig. 10). Maximum WAI isabout 4, occurring at 375 0 F (191 °C) for the 15% moisture sample

an d at 325°F (163°C) for the 25% moisture sample. In the other

400 0F(204°C)

Temperature

Fig. 4. Roll cooking of barley grits: Effectof temperature and moisture onwater-absorption index (WAI) and water-solubility index (WAI).

lS00 r - - - - - - - - - - - - - - - - - - - - ~

o"====:::::r:::_..l.----l_--L_...L-_L---l._-L--.Jo 10 20 30 40 50 60 70 SO 90

Minutes

f - - - - - Heat .. I Hold • I Cool---J

29'C 95'C 95'C 50'C

Fig. 5. Roll cooking barley grits: Effect of temperature on viscosity (15%

moisture).

1200

900

'2=>

600

Id5

300

450'FI232'CI

250'FI121'CI

/ ------- .../s'50'FI28S'CI

..-...._-----_ ... .."""",.- ...

o! = ; : r , ; ; ; ; ; ; ; ; ; ; ~ = _ . . L _ _ _ l _ _ _ _ L - - - . J _ . . L _ - L ~o 10 20 30 40 50 60 70 SO 90

Minutes

I Heat • 1 Hold • I Cool- - -J

29'C 95'C 95'C 50'C

Fig. 8. Roll cooking of rye grits: Effect of temperature on viscosity (15%

moisture).

Temperature

Fig. 7. Roll cooking of rye grits: Effect of temperature an d moisture on

water-absorption index (WAI) and water-solubility index (WSI).265'F1129'CI

300

600

1500

, 1200

:5

1900

ti;

Vol. 59, No.4, 1982 267



90

555'FI290'CI

80000000

1500

1200

:3 900

-g

= 600cD

I

300

10 ,----------------------,

when compared to the other cereals. After a slight increase, peakin

at abou t 300° F (149°C ), the WSI decreased to a minimum

400-425°F (204-218° C) and then rose sharply as temperatur

were increased. Figure 11 shows viscosi ty curves for oa t gri

processed at 15% moisture and at four different temperature

Initial paste viscosity (29° C) was the same for samples cooked

25% moistur e (Fig. 12). In both moisture series, peak viscosi

occurred in samples cooked at 265° F (129° C). With the exceptio

of the 25% moisture sample cooked at 320° F (160° C), final cooke

paste viscosi ty (50° C) decreased as temperature increased in

manner similar to that observed with viscosity patterns of the oth

cereals roll cooked under like conditions.

Comparisons of WAI values of grits from different graincooked at 25% moisture overa range of temperatures are given

Fig. 13. Data fo r corn and sorghumare from Andersonet al (1969

1969b). Characteristic WAI curves were obtained from all th

g rains ex cept oa ts, with WAI peaking for all but oats

temperatures from 400°F (204° C) to 450°F (232°C). The curve fo

oats showed very little change over the complete range

temperatures used. The peculiar behavior of oa t grits perhaps ca

be attributed to the considerably greater amount of oil and crud

f iber present in oats. Although not shown, the water solubility

cooked grits from the different grains was similar, ie, with little

no change in WSI until about 400°F (204° C), then increasingas th

temperature of cooking was increased. Wheat and rye showed th

highest WSI, which was attained at 550°F (288°C). A small peak

about 300°F (149° C) on the WSI curve for oat grits was not note

on the others, bu t the remainder of the curve followed thcharacteristics of the other grains. However, the value at 550°

(288° C) was somewhat less than those from the other grains und

study.

Table II gives comparative amylographdata for selected sampl

of roll-cooked grits from the different grains studied. Except fo

corn. all samples were cooked at 25% moisture content and

approximately 400° F (204° C). The corn sample was cooked

50

Minutes

f - - - - - Heat • I Hold • I Cool-j

29cC 95'C 95'C 50'C

Fig. 12. Roll cooking of oat grits: Effect of temperature on viscosity (25

moisture).

260'FI127CCI

550'FI2BB'C!

/ '

/ , - -405 cFI207'CI

- - - - ~ . . ; " " "

/' ./ \

/ \/ / \

_/--

4

300

900

t 600

cD

10 r----------------. . . ,

2 ' - - - - L . . - - - - . . L - - - - - . . . 1 . - - - - - - - - '

cereals, maximum WAI generally occurred from 410° F (210°C) to

450° F (232° C), and WAI was 6 or higher. For the cooked oats,

WAI increased at high cooking temperatures after showinga slight

decrease. This phenomenon did not occur with WAI of o ther

cereals, in which WAI declined after reaching maximum. Oat grits

cooked at 500° F or higher (260° C) started browningand exhibited

other appearance characteristics similar to those noted with the

other cereals cooked at temperatures exceeding 500° F (260° C).

Water-solubility index curves indicate rather atypical patterns

21. . . . - - . . . J . - - -_--- I . . . . ! - -- j

« 8s:x

'"c-= 6c::

.

.. Q

o'".Q«

1200 , - - - - - - - - - - - - - - - - - - - - - - ,

400 DF

(204DC)

Temperature

Fig. 10. Roll cooking of oat grits: Effect of temperat.ure and moisture onwater-absorption index (W AI) and water-solubility index (WSI).

o ~ ~ ~ ~ : : . = . : : : : : : r : : . : : : = . : i = - - - L - - - - l . _ . . L - - L ~o 10 20 30 40 50 60 70 BO 90

Minutes

f---- Heat • 1 Hold -I Cool-j

29'C 95'S 95'C 50'C

Fig. 9. Roll cooking of rye grits: Effect of temperature on viscosity (25%

moisture).

Rye

8arley - - - : : / . Corn

\ /,-' 7 ...... /", ' " -- "-/'" ,,---""""""'=.---,

....'" ,At::-:::.\------- ............."" -/--- ......:--., ..

/' /" : / '" Grain Sorghum Wheat - - - - - - ~ _Co1 ~ ~ ~ ~ Oats

;;: 4 ./~ ~ - - - - - - - / -------~ - - - - - - - - - - - - - - -

1200

900

'" ,

::>

m 600""m"";:"" 300

o~ ~ ! ! ! ' ! ! ! ! ! ! ! ! ! ! ! ! ! ! E : = : ; ; = = = = : : = . : : : : r . : ~ _ . . . . L - - - . Jo 10 20 30 40 50 60 70 80 90

Minutes

f---- Heat .. I Hold • I Cool-j

29'C 95'C 95'C 50'C

Fig. 11. Roll cooking of oat grits: Effect of temperature on viscosity (15%

moisture).

300'F 400'F1149'CI i204'CI

Fig. 13. Roll cooking studies: Water-absorptiondifferent grains roll cooked at 25% moisture.

500'F(260'CI

index of grits from

268 CEREAL CHEMISTRY



TABLE II

Amylograph Data for Roll-Cooked and Uncooked Cereal-Derived Grits

Viscosity'Final Cooked Paste

Sample ViscosityIdentification at 29°C at 95°C Peak at 95° C for 16 min (50°C)

BarlevC o ~ k e d b 605 1.200 1,820 470 850Uncooked 10 I.l40 1,140 580 1.240

Rye

Cooked" 330 575 1,100 450 780Uncooked 20 200 230 210 540

Wheat

Cookedb 60 420 480 240 505

Uncooked 0 180 180 180 390Oats

Cookedb

30 420 450 360 960Uncooked 20 380 405 280 850

Corn'

Cooked" 320 260 490 210 450Uncooked 30 280 280 330 730

Sorghum'

Cooked' 170 240 330 240 330Uncooked 20 300 300 280 700

'I n Brabender units.

bCooked at ~ 4 0 0 ° F (204°C) at 25% moisture.

,Anderson et al (1969a, 1969b).

dCooked at ~ 4 6 5 ° F (240° C) at 20% moisture.

465°F (240° C) at 20% moisture. Amylograph data for uncooked

grits from the grains are also included. The viscosity data followedthe amylograph patterns expected from both the cooked and

uncooked grits, Viscosity developed slowly as the temperature of

the material was being increased to the point of gelatinization, at

which viscosity peaked, of ten dramatically. It decreased when

material was stirred at 95° C for 16 min, and once again increased

during the cooling cycle to the final cooked paste viscosityat 50°C.

Uncooked wheat , oats, rye. corn, and sorghum gri ts had similar

amylograph pat terns, with some minor variations. Uncookedbarleygrits, on the other hand. gave unusually high values for both

peak and final cooked paste viscosity. Viscosity values that werehigher than usual also were obtained from the cooked barley grits.

Cooked rye grits gave a some\vhat higher viscosity pattern than didthe wheat. oats, corn, or grain sorghum.

These studies show that a b road range of products possessing

dif ferent vi scos ity character is ti cs can be made by roll cookingcereal grits under different conditions of temperature and moisture.

Furthermore, the various cereal grains, either cooked or uncooked,

can exhibit viscous properties that differ from one another.

LITERATURE CITED

AMERICAN ASSOC IATION OF CEREAL CHEMISTS. 1962.

Approved Methods of the AACC. Methods 08-01, 30-20, 32-15, and

46-10, approved April 1961. The Association, St. Paul. MN.

ANDERSON. R. A., CONWAY, H. F., PFEIFER, V. F., and GRIFFIN,

E. L., Jr. 1969a. Gelat in izat ion of corn gri ts by rol l and extrusion

cooking. Cereal Sci. Today 14:4-12.

ANDERSON, R. A.. CONWAY. H. F. , PFEIFER, V. F., and GRIFFIN,

E. L., Jr . 1969b. Roll and extrusion cooking of grain sorghum grits.

Cereal Sci. Today 14:372-375.

ANDERSON, R. A .• CONWAY. H. F., and PEPLINSKI. A. J. 1970.Gelatinization of corn gri ts by roll cooking , ext rusion cooking and

steaming. Staerke 22: 130-135.

KITE, F. E., SCHOCH. T. J.. and LEACH. H. W. 1957. Granule swelling

and paste viscosity of thick-boiling starches. Bakers Dig. 31(4):42-44.

POWELL, E. L. 1967. Production and use of pregelatinized starch. Page

523 in: Starch: Chemistry and Technology. Vol. II. R. L. Whistler and

E. F. Paschall, eds. Academic Press, New York.

WHISTLER, R. L. 1970. Industrial uses of corn starches. Page 171 in:

Corn: Culture, Processing, Products. G. E. Inglett, ed. Avi Publishing

Co., Westport, CT.

[Received October 19, 1981. Accepted January 25, 1982J

Vol. 59. No.4. 1982 269

ika dan ipa di produk

Documents