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THESIS
STARCH AS FOUND IN

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SEWICR AGRICULTURAL THESIS.

"STARCH AS FCUND IN VEGETABT.E FCCDS"

BY

ANNE CATHERINE WATKINS.

Michican Agricultural Collese,1898.
THESIS
STARCH (C6H1QCs)-

Plants produce by asSSimilation a larger amount of Sub-
Stance than tney can emplov at the time for cell growth.
Tris substance is stored in the cells and is curried ir s0-
lution through the plant from the protoplasm,where it is first
visible,to the chlorovhnyll granules.

Starch grains have always, origineally,a rounaed form,
usually spherical until vcrowtn presses them into the varied
forms in weich we find them.

Sturcn is never found in a perfectlv pure state,always
containing water of oreunizat ion. The luvers of stratifi-
cation ure alternately transparent and dark; those farthest
from the nucleus being the most watery and that luyer near-
est,being the most dense. This last laver surrounds the
Small,very watery certre,called the nucleus.e All lavers are
disroseqd about the nucleus aS a conron centre,-the size of
the layers increusins toward the direction of most vigorous
Browthe Growth accomplished wholly be intussusception.

Starch is a product formed by the vitul uctivity of
Plants. The umount of starch is increused bv light und con-
tains a lesser or ecreater amount of water acxordineg to the
variety of the plant in which it is found. It consists of
a soluble und an insoluble muss, granulose and oe lulose ,and
these two masses can be SeDarated by the action of Saliva or

pepsin. Starch is insoluble in cold water and swells tO a

104055
(2)
Sticky paste with boiling water. Grarules heated gsentlr to
40° or 509% C.,will snow lines of stratificution much pluiner.
Caustic potash and chronic acid act or Starch with the Same
result.

Sturch is colored by iodine from u very pale hlue to
purtie or bluck,according to cre streneth usec. Tris is the
princiviaul test for staracr.

Starch cellulose is only au small proportion(2%-6%) of starai.
ani mav be describe’! as tne skeleton of the starch granules.

Granulose muv be extrasted in several wus?

1. Muceration in Sulivu at 409-479 C.

2. By organic acids,diastase or pensin.

3. Rv slow uwotion of verv dilute HoSCq, or HCL.
"he volume of a Starch granule can be increased 125% heat-
ine or by tne action of caustic rotush.

Starch prauins mav be classified accordinre to size,the
limits ,nowever,beirg .~CC2 meme to those visihls to the mak-
ed eye:

small,(-CC2 = «C15 mm) which includes starches of rice,
Outs ,yobuck-wheat,and tre smaller ones of wheat,yrye and barley.

Medium,(.C2 - .C5 mm) as the gormound grariles of outs
and rice ,and the lurser ones of wheat yrve and burlev.

Large ,(visible to the naked eve) as potato,cunna etc.

Potato starch was discovered durine the 17th century,
(<3)
and Since that we nuve in use Starches from néurly all of
the edible plantS,most of which are illustruted in the Plates
of this thesis. The Starch of wheat was the only kind known
to the AncientS,and vias used extensivelv bv the keyptians
and the Greeks.

In murny plants we kruve not only sinele sturech grains;
but also aouble,trinle und even auudruvle erains. These
eonpound gruins uSuully corntair. aS manv nuclei us thev have
divisions ,and ure joined bv several lines of stratification,
wreile the remaining layers extend ahout onlv their individ-
uul nuclei. There are ulso sirnple or compound erunules where
the compound ones often contuin eist or ten Simvle ones.

etarch anreurs in nearly wll chloropryll beurine plants.
It wus most lacking ,however,in the Sugur beet and was distine-
uishanle in minute granules in the currot,ruta baga etce

Heated with dilute nitric ucid the sturch is converted
into dextrin and finally irto grave Sugar. It iS On account
of this that starch is used to obtain glueose on a large
Scale.

Stareh is used for munvy purposes: us a food, as glue, as
uw medicine und in tre luundry.

Potato Starch is obtained bv prutine the tubers and pass-
ing water over them until the water is no longer milky,vwhich

color is cuused bv the Stureh held in solution. Tre starch
(4)

will soon sink to the bottom und cun be thus obtained. The

process of obtaining wheut,yrve and other sturches,is mush

=

more difficult ;though essentially the sume.

Notes on Plate I.

A.- Wild ctotato from Mexico,(varent of our cultivated vota-

to)

averuge size;

ae- Cocsked Sturch granule Showing fisSuresS. Greuat-
ly increased in size bv cooking.

be- Double granule with two nuclei.

Ce- Lore, ,slender,crooked eriumale.(rure)

de- Tricle grurule.

e.- Nearly circular granule.

f.- Most comion shaped grain of lurge size.

B.- Wild votuto of Arizona; medium Size wild:

ae- Grunule with nucleus at large end(most corimon).
KH - u ry Vv " Smal 1 " e

Ge- Xtra large yneurly oval granule.

de- Angular grurule.

€e~- Stur-Shuped granule.

P.e- Grarule with smull granude imbesied in one end.
G-h-1.- Types of grains.

m-ne= Cooked stura shoving menhrane at end ard fis-

Sures on surface.

In tris potuto,nucleus found most generally at lurge end.

 
Lanna re

(5)
C.- Piece of hreud seovwine muss of Sturmch etc. utter pro-
eess of conKine?
ae- Cooke? wheat sturck grain,fPluttered ani mich en-
lurged,thougsh still retaining original shure.
be- Grain snowing slighe lines of stratification,
which in wheat Stureh are usuallv invisible.
QA.- Granule shovine no lines of Stratifiszution.
Aeeef.- Cooked erauins tvisted wet turned during pro-
cess of convirg.e
he-i-j-k.=- Portions of wheat Starch frains imbedied
in gum urubic,to rold in pluce and tren cut a-
Gross to Snow Srape etc.
De- Cell from bananu vulp, containing Stureh grains of iiffer-
ent sizes and shaves?
dee Long, ytuprring grunule with nmacleus ut one end.
be- Varirus Snaupeld grains.
de- Cooked grain Snowing creat increase in size.

e.e- Loneg,yslender sonked eranale.

 

Notes on Plute II.
se- Cell contuininzg Starsh grains from the veollow flinty
portion of corn. Grurules closelv pucke il in the cell.
a-be- Lifterent forms of Starch Shovwine nucleus ut
the centre and radial lines running from it.
Grains angular in Svnupne.

Fe- Cell with its staurehn,from white vart of corn. Granules
 

(46)
less tnick in cells,less unsyuluryand each wavine a small
solit or fissure, ,often Star-Shured,in tre centre.
Gee Two cells of vwon-corn unvopned.
He- no " " Somewnat pooved,yund Snowine tne en-
largement of the cells und the action of heat wo98N them.
I.- Fully vorved corn srowing cells greatlv extended, .nd the
wavy Lines (u) showing themelted starch imitatine true
Plunt 2f11S.e
Ke- Masses of buck-wheut Sturoh granules filling the cells.
Te- Crarules of rve Suurch rowing no lines of stratifica-

tion and varvine in size and Supe.

Notes on Plate III.

 

Me- Portion of au aross seation of « kernel of out. Cells of
different sizes
ae- Pallisude cells contuinine Aleurone.
De- Sturch found in the centre of section of kernel.
GCe- Compound granule of out Starch shovine vortion
broken off.
de=- “YoOl] com™ound granule.
ee- Single grains broken from the compound grain.
fe- Conked out-meal showing compound grain enlursed
oy heate
Ne- Section from rice kernel:
uwe- Aleurone cells.

He- Cells of Sturen grains.
S.-

Ver

(7)
Ge- Comround grains of rice starch and tre separate
kernels.

Portion of a wneut kernel:

ade- Aleurone c#lls with thick valls.

He- Sturen cells with thin walls.
Various sizes und Shapes of the arrow root Stara erun-
ules,svowing plainly lines of ctratificution.
Granules from barlev Sturche
Grain from Solanum Mavliu of Souwtn America. Remarkably
varied in size and Srune.
Cranules form Allico Solernum of S.A... Used aS ua Potato
in Peru. Tiines of Stratification seldom visible.
Sturan from vea?

awe- Heart-Shuved pranule.

be- Doudle grunule.

Ce- Nearly trirle granule.
Tapioca Sturch, various sizes:

ae- Craurule with end sut off.

be- Cooked grains distorted and enlurged hv heute.
Feaun Starans

wen Boar, original size.

be- Doudl? granule Of heun Stars.

Yer Very minute gramiles of Staroh from the Ruta Ruga,starch

Pound about one ineh from the surface. Visible only by

usc of iodine.
FLAP ES VG:

 

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