KLEVORN,)CLAIRE)MARIE.)Development)of)Lipid)Components)of)High?)and)Normal? Oleic)Peanuts.)(Under)the)direction)of)Lisa)L.)Dean).)
The)quest)for)accurate)methods)for)the)determination)of)peanut)seed)maturity)is) ongoing.)Much)work)has)been)done)to)identify)seed)components)which)can)serve)as) maturity)indices.)Studies)in)the)field)of)peanut)maturity)have)focused)on)understanding) how)various)components)of)the)seed)change)as)the)plant)matures.)The)development)of) peanut)cultivars)with)increased)oleic)acid)content)has)raised)questions)as)to)how)
development)of)the)lipid)fraction)of)the)seed)occurs.)These)questions)are)the)result)of)an) inconsistent)supply)chain)where)high?oleic)lots)are)contaminated)with)normal?oleic) seed.)Specifically,)this)work)aimed)to)test)the)theory)that)large)seeded,)high?oleic)
Virginia)type)peanut)cultivars)become)commercially)large)enough)before)maturation)so) that)immature)seeds)still)expressing)normal?oleic)levels)contaminate)high?oleic)lots.)In) order)to)accomplish)this,)a)high?oleic)cultivar)(Spain))and)a)low?oleic)cultivar)(Bailey)) were)planted)and)monitored)weekly)for)pod)and)seed)weight,)pod)maturity,)moisture) content,)fatty)acid)profile,)and)phytosterol)content.)The)results)of)these)analyses) indicated)that)maturity)plays)a)significant)role)in)dictating)the)compositional)
sorting)using)size,)it)is)improbable)that)totally)pure)high?oleic)lots)will)be)obtained.)
) ) ) )
)
) ) ) ) ) ) ) )
) by)
Claire)Marie)Klevorn) )
)
A)thesis)submitted)to)the)Graduate)Faculty)of) North)Carolina)State)University)
in)partial)fulfillment)of)the)) requirements)for)the)degree)of)
Master)of)Science) )
) Food)Science)
) )
Raleigh,)North)Carolina) 2014)
) ) ) )
APPROVED)BY:) )
)
_______________________________) ) ) ______________________________) Dr.)Lisa)L.)Dean) ) ) ) Dr.)Timothy)H.)Sanders) ) Committee)Chair) )
)
DEDICATION'
BIOGRAPHY' '
'
ACKNOWLEDGEMENTS' '
'
I)would)like)to)thank)everyone)who)helped)me)through)my)masters)program.))Thank) you)to)my)advisor,)Dr.)Lisa)Dean)for)giving)me)the)opportunity)to)continue)my)
TABLE'OF'CONTENTS' '
'
LIST'OF'TABLES'...'vii)
LIST'OF'FIGURES'...'viii)
CHAPTER'1:'INTRODUCTION'...'1)
REFERENCES)...)8)
CHAPTER'2:'LITERATURE'REVIEW'...'9)
PEANUTS)...)10)
Importance+to+Industry+and+Background+...+10)
Growth+and+Development+...+11)
Physiology+...+16)
Oil+synthesis+...+17)
HIGH?OLEIC)PEANUTS)...)20)
Development+...+20)
Advantages+over+traditional+cultivars+...+21)
Importance+to+industry+...+22)
HARVEST)AND)POST?HARVEST)OPERATIONS)...)23)
Harvesting+and+Curing+...+23)
Warehouse+Storage+...+25)
Methods+for+Evaluating+Oil+Content+...+26)
RESEARCH)OBJECTIVE)...)29)
REFERENCES)...)46)
CHAPTER'3:'THE'IMPACT'OF'NORMAL'PEANUT'DEVELOPMENT'ON'THE'LIPID'PROFILE' OF'THE'MATURING'PEANUT'SEED'...'51'
MATERIALS)AND)METHODS)...)52)
Determination+of+Fatty+Acid+Profile+...+52)
Determination+of+Phytosterol+Content+...+55)
Genotyping+of+Varieties+...+56)
Determination+of+Maturity+Classes+...+57)
Statistical+Analysis+...+58)
RESULTS)AND)DISCUSSION)...)58)
Pod+and+Seed+Development+...+58)
Analysis+of+Moisture+Content+...+63)
Analysis+of+Maturity+...+76)
Analysis+of+Phytosterols+...+81)
Analysis+of+Genotypic+Data+...+83)
CONCLUSIONS)...)84)
LIST'OF'TABLES' '
' Chapter'3'
Table)1.)Mean)O/L)ratio)for)early,)middle,)and)late)harvest)dates)by)variety)...)134) Table)2.)Average)and)standard)deviation)of)phytosterol)content)for)Bailey)seeds)for) early,)middle,)and)late)harvest)dates)...)135) Table)3.)Average)and)standard)deviation)of)phytosterol)content)for)Spain)seeds)for) early,)middle,)and)late)harvest)dates)...)136) Table)4.)Genotypic)data)for)a)selection)of)Bailey)and)Spain)seeds)harvested)during)the) 2012)growing)season)...)137)
LIST'OF'FIGURES' '
' Chapter'1'
Figure)1.)Work)demonstrating)high?oleic)seed)contamination)with)seed)expressing) normal?oleic)O/L)ratios)(Davis)2011))...)6) Figure)2.)Work)demonstrating)the)relationship)between)seed)size)and)O/L)ratio)(Dean) 2013))...)7) Chapter'2'
Figure)1.)Peanut)producing)regions)of)the)U.S.A.)(American)Peanut)Council)2011))...)30) Figure)2.)Root)system)of)the)peanut)(Marsalis)et)al.)2009))...)31) Figure)3.)The)peanut)flower)(American)Peanut)Council)2011))...)32) Figure)4.)The)desiccated)flower)as)the)peg)begins)to)move)toward)the)soil)surface)for) seed)development)(American)Peanut)Council)2011))...)33) Figure)5.)Peanut)pods)of)different)maturities)on)the)same)plant)(American)Peanut)
Figure)10.)A)digger)completing)the)first)stage)of)the)peanut)harvest,)digging)(American) Peanut)Council)2011))...)39) Figure)11.)Dug)peanuts,)which)have)be)placed)into)windrows)for)drying)(American) Peanut)Council)2011))...)40) Figure)12.)Combining)peanuts,)seeds)are)blown)into)the)hopper)(American)Peanut) Council)2011))...)41) Figure)13.)Drying)wagons)used)to)complete)the)second)stage)of)the)curing)process) (American)Peanut)Council)2011))...)42) Figure)14.)Sorting)of)shelled)peanuts)(American)Peanut)Council)2011))...)43) Figure)15.)Bulk)shelled)peanut)warehouse)storage)(American)Peanut)Council)2011))....)44) Figure)16.)In?line)color)sorter)to)kick?out)discolored)seeds)(American)Peanut)Council) 2011))...)45) Chapter'3'
Figure)5.)Seed)moisture)content)as)a)percentage)of)wet)weight)(g))for)weekly)harvests) for)Bailey)and)Spain)cultivars)...)105) Figure)6.)Summary)of)seed)moisture)content)as)a)percentage)of)wet)weight)(g))for) weekly)harvests)for)Bailey)and)Spain)cultivars)where)color)labels)correspond)to)the) weekly)color)assignments)in)Figures)4)&)5)...)112) Figure)7.)Relationship)between)O/L)ratio)and)fresh)seed)weight)for)early,)mid,)and)late) harvest)dates))for)Bailey)and)Spain)cultivars)...)113) Figure)8.)Development)of)oleic)acid)(18:1)))as)a)percent)of)total)fatty)acid)content)across) early,)middle)and)late)harvest)dates)for)Bailey)and)Spain)cultivars)...)114) Figure)9.)Development)of)linoleic)acid)(18:2))as)a)percent)of)total)fatty)acid)content) across)early,)middle)and)late)harvest)dates)for)Bailey)and)Spain)cultivars)...)115) Figure)10.)Development)of)O/L)ratio)across)early,)middle)and)late)harvest)dates)for) Bailey)and)Spain)cultivars)...)116) Figure)11.)O/L)ratio)broken)down)by)size)classification)for)Bailey)and)Spain)cultivars )...)117) Figure)12.)Content)of)oleic)acid)(18:1))as)a)percent)of)total)fatty)acids)broken)down)by) size)classification)for)Bailey)and)Spain)cultivars)...)118) Figure)13.)Content)of)linoleic)acid)(18:2))as)a)percent)of)total)fatty)acids)broken)down) by)size)classification)for)Bailey)and)Spain)cultivars)...)119) Figure)14.)Interaction)plot)showing)the)change)in)log)transformed)mean)O/L)for)
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The)peanut,)(Arachis+hypogaea+L.),)is)a)legume)that)originated)in)South)America.) Current)global)peanut)production)totals)approximately)29)million)metric)tons)annually) with)the)United)States)as)the)third)largest)producer)following)China)and)India,)
respectively)(American)Peanut)Council)2013).))In)the)U.S.A.,)seven)states)(Georgia,) North)Carolina,)Virginia,)Texas,)New)Mexico,)Oklahoma,)and)Florida))account)for)99%)of) the)peanut)production.))Within)the)United)States,)4)market)types)(Runner,)Virginia,) Valencia,)and)Spanish))are)produced.))The)majority)of)the)peanut)crop)produced)in)the) United)States)is)grown)as)a)food)crop.))Peanuts)are)used)in)food)products)not)only) because)of)their)appealing)flavor)but)also)due)to)their)perceived)positive)health)effects) due)to)their)lipid)composition)and)significant)protein)content)(American)Peanut)Council) 2013).)
)
The)shelf)life)and)quality)of)peanut)products)is)largely)related)to)the)composition) of)the)oil)within)the)seed.))Palmitic,)oleic,)and)linoleic)acid)are)the)primary)fatty)acids) present)within)the)peanut)seed)(Ahmed)1982).))High?oleic)peanut)cultivars,)that)is)those) where)the)ratio)of)the)percent)oleic)to)linoleic)acid)in)the)oil)is)greater)than)9,)were) reported)in)experimental)lines)in)1987)(Norden)1987).))The)discovery)of)high?oleic) peanuts)resulted)in)production)of)peanuts)with)increased)oxidative)stability)compared) to)traditional)cultivars)(O’Keefe)1993).))Use)of)high?oleic)peanuts)in)value)added) products)allows)processors)to)extend)flavor)stability)during)product)storage.))The) increased)oleic)acid)content)of)these)peanuts)decreases)the)incidence)of)lipid)oxidation) preventing)the)formation)of)off?flavors)associated)with)this)process)(Braddock)1995).)
)
Food)manufacturers)currently)utilize)the)more)expensive)high?oleic)nuts)for) products)containing)whole)nuts.))When)normal)oleic)seeds,)which)have)noted)decreased) shelf)stability,)are)used)the)nut)can)develop)off)flavors)more)quickly)and)repeat)
Presently,)the)industry)routinely)stores)various)lots)of)peanuts)separately,)e.g.)raw) separate)from)roasted,)the)various)market)types)separate)from)each)other,)or)whole) nuts)separate)from)split)and)blanched.))In)each)of)these)instances,)the)difference)among) the)various)items)is)readily)apparent)to)the)eye.))This)is)not)true)of)the)high?oleic)trait,) which)can)only)be)determined)by)some)type)of)compositional)testing.))The)
contamination)could)have)occurred)via)one)of)the)mechanisms)listed)above)however)an) additional)mechanism)of)contamination)was)suspected.))It)was)postulated)that)normal? oleic)seed)could)occur)among)high?oleic)seed)if)all)high?oleic)seed)started)out)as)normal? oleic)and)became)high?oleic)during)normal)development.))As)an)example,)a)preliminary) study)was)conducted)using)certified)seed)of)the)high?oleic)variety)Brantley)(Dean) 2013).))It)was)found)that)O/L)ratio)was)highly)correlated)with)seed)size)and)that)the) smaller)seeds)of)this)high?oleic)line)were)actually)still)in)the)range)of)normal?oleic)(O/L) <)9))(Figure)2).))If)such)seed)were)large)enough)to)make)it)past)industry)seed)sizing)into) lots)used)by)manufacturers,)then)problems)with)shelf?life)of)the)normal?oleic)kernels)in) whole)nut)products)could)occur.))Although)many)of)the)potential)contamination)
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Figure!1.!Work!demonstrating!high4oleic!seed!contamination!with!seed!expressing!normal4oleic!O/L!ratios!(Davis!2011)! !
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Figure!2.!Work!demonstrating!the!relationship!between!seed!size!and!O/L!ratio!(Dean!2013)
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REFERENCES'
Ahmed,!E.!M.,!&!Young,!C.!T.!(1982).!Composition,!quality,!and!flavor!of!peanuts.!In!H.!E.! Patee,!&!C.!T.!Young!(Eds.),!Peanut'science'and'technology!(pp.!655I688).!Yoakum,! Texas:!American!Peanut!Research!and!Education!Society,!Inc.!!
American!Peanut!Council!(2013).!About!the!peanut!industry.!!Retrieved!from! http://www.peanutsusa.com/aboutIpeanuts/theIpeanutIindustry3.html!
Braddock,!J.!C.,!Sims,!C.!A.,!&!O'Keefe,!S.!F.!(1995).!Flavor!and!oxidative!stability!of! roasted!highIoleic!acid!peanuts.'Journal'of'Food'Science,'60(3),!489I493.!
Davis,!J.P.!(2011)!Unpublished!Data.!!
Dean,!L.!L.,!Klevorn,!C.!M.,!Hendrix,!K.!W.,!Davis,!J.!P.,!&!Sanders,!T.!H.!(2013).!
Development!of!lipid!components!of!highI!and!normalIoleic!peanuts.!American'
Peanut'Research'and'Education'Society!,!Proceedings!of!the!45th!Annual!Meeting.!!
Norden,!A.!J.,!Gorbet,!D.!W.,!Knauft,!D.!A.,!&!Young,!C.!T.!(1987).!Variability!in!oil!quality! among!peanut!genotypes!in!the!Florida!breeding!program.'Peanut'Science,'14(1),!7I 11.!
O'Keefe,!S.!F.,!Wiley,!V.!A.,!&!Knauft,!D.!A.!(1993).!Comparison!of!oxidative!stability!of! HighI!and!normalIoleic!peanut!oils.'Journal'of'the'American'Oil'Chemists'Society,' 70(5),!489I492.!!
Williams,!E.!J.!&!Drexler,!S.!J.!(1981).!A!nonIdestructive!method!for!determining!peanut! pod!maturity.!Peanut'Science,'8!(2),!134I141.!
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PEANUTS'
Importance'to'Industry'and'Background'
Peanut!(Arachis'hypogaea'L.)!is!an!allotetraploid!species!that!serves!as!an!
important!food!and!oil!crop,!and!is!cultivated!around!the!world!in!tropical,!subItropical,!
and!temperate!climates!(Wang!2011).!!It!is!used!for!a!multitude!of!purposes!including!
food,!animal!feed,!and!industrial!raw!material!(Maiti!2002).!!Along!with!soybean!
[Glycine'max!(L.)!Merr.]!the!peanut!is!categorized!in!the!Leguminosae!family!although!it!
more!closely!resembles!tree!nuts!rather!than!most!beans!or!peas!(Holaday!1979).!!
Because!the!seed!has!a!lipid!content!between!36!and!54%,!a!majority!of!the!worldwide!
crop!is!grown!as!oilseed!(Stalker!1997).!!!Peanut!oil!is!pale!yellow!with!a!distinctive!
nutty!taste!and!odor,!which!is!obtained!from!the!processing!of!peanut!kernel!(Carrin!
2010).!!In!contrast!to!the!worldwide!crop,!most!of!the!crop!grown!in!the!United!States!
and!South!America!is!sold!as!food!(Stalker!1997).!!Peanut!seeds!serve!as!an!important!
dietary!contributor!in!many!countries!due!to!their!favorable!protein,!lipid,!and!fatty!
acid!composition!(Carrin!2010).!!!
!
In!the!United!States!approximately!1.9!million!tons!of!peanuts!are!produced!
annually!on!1.44!million!acres.!!Of!this,!99%!of!the!peanut!production!occurs!in!seven!
states:!Georgia!(41%),!Alabama!(10%),!Florida!(6%),!Virginia!(5%),!North!Carolina!
the!U.S.A!(American!Peanut!Council!2011).!!Peanut!production!in!the!U.S.A.!is!comprised!
of!four!dominant!market!types!(American!Peanut!Council!2011).!!These!are:!runner,!
Virginia,!Spanish,!and!Valencia.!!Runners!account!for!the!majority!of!the!peanut!crop!
produced!as!they!represent!80%!of!total!US!production.!!They!are!typically!grown!in!
Georgia,!Alabama,!Florida,!Texas!and!Oklahoma.!!A!large!portion!of!runners!produced!is!
used!in!the!production!of!peanut!butter.!!VirginiaItype!peanuts!represent!15%!of!the!
peanut!production!in!the!US.!!This!market!type!is!characteristically!grown!in!
southeastern!Virginia,!northeastern!North!Carolina,!and!West!Texas.!!Virginias!are!
typically!sold!inIshell!or!shelled!in!the!form!of!salted!peanuts.!!Spanish!peanuts!account!
for!4%!of!US!peanut!production!and!are!generally!grown!in!Oklahoma!and!Texas.!!These!
peanuts!have!the!highest!oil!content!of!the!market!types!and!they!are!used!primarily!in!
candies!containing!peanuts.!!The!final!market!type!produced!in!the!U.S.A.!is!Valencia.!!
This!market!type!accounts!for!less!than!1%!of!the!total!production!and!is!grown!
predominantly!in!New!Mexico.!!Additionally,!Valencia!peanuts!typically!have!three!or!
more!kernels!per!pod!and!they!are!sweeter!than!the!other!market!types!(American!
Peanut!Council!2011).!!!
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Growth'and'Development'
! Peanut!is!an!annual!legume!that!grows!close!to!the!ground!and!produces!fruit!
means!that!peanut!roots!produce!nodules!(Figure!2)!that!allow!them!to!absorb!nitrogen!
from!the!air!and!reduce!it!to!an!amine!form!to!provide!nutrients!to!the!plant!(American!
Peanut!Council!2011).!!In!the!United!States,!peanuts!are!planted!after!the!last!frost!of!
the!season!typically!between!April!10!and!May!10!for!the!majority!of!the!peanut!
growing!region!(Henning!1982).!!A!successful!growing!season!usually!contains!
approximately!200!frostIfree!days!and!occurs!between!April!and!October.!!A!complete!
growing!cycle!from!planting!to!harvesting!is!typically!four!to!five!months!in!length!and!
is!dependent!on!the!location!and!the!cultivar!grown!(American!Peanut!Council!2011).!!
Peanuts!are!best!grown!in!sandy,!loamy!soils!with!good!drainage!because!this!type!of!
soil!allows!for!the!pods!to!easily!expand!and!be!removed!from!the!ground!during!
harvesting!(Henning!1982).!!Planting!generally!occurs!when!soil!temperatures!reach!
20°!C.!!In!order!to!prepare!an!adequate!seedbed,!fields!are!often!tilled!prior!to!planting!
to!ensure!the!burial!of!all!previous!plant!material!and!weed!seeds!(Henning!1982).!!
Seeds!are!planted!4I5!cm!deep!and!5I15!cm!apart!depending!on!the!growing!region!
(American!Peanut!Council!2011).!!Row!spacing!is!dependent!on!the!type!of!equipment!
utilized!for!planting!and!harvesting!the!crop.!!When!grown!in!a!warm!climate!with!
adequate!moisture!and!fertile!soil,!the!peanut!plants!produce!leaves!10I14!days!after!
planting!(DAP).!!To!control!broadleaf!weeds!and!grasses,!peanuts!are!cultivated!once!or!
twice!during!the!growing!season!(Henning!1982).!!Disease!is!often!caused!by!fungal!
organisms!and!generally!requires!chemical!treatment!for!management!(American!
! The!development!of!legume!seeds!is!established!as!the!differentiation!of!organs!
and!tissues,!which!create!a!developmental!gradient!(Weber!2005).!!Due!to!the!
indeterminate!growth!habit!of!the!peanut,!determination!of!the!physiological!age!of!an!
individual!seed!has!proven!to!be!a!challenge!(Pattee!1974).!!Development!of!the!peanut!
occurs!in!a!successive!manner!(Weber!2005).!!Peanuts!begin!their!growth!cycle!with!
germination!(Munger!1998).!!This!process!occurs!from!the!time!that!the!seed!is!planted!
until!it!emerges!through!the!soil!surface.!!During!germination,!metabolic!activity!begins!
in!the!seed!due!to!the!hydration!of!cell!walls!and!the!protoplasm!(Ketring!1982).!!The!
primary!root!system!of!the!plant!is!tap!rooted,!however,!three!days!following!
germination!many!lateral!roots!begin!to!develop!(Stalker!1997)!(Figure!2).!!The!tap!root!
is!the!first!root!to!emerge!from!the!seed!with!the!lateral!roots!being!those!which!branch!
from!the!tap!root!(Zobel!2010).!!Once!the!cotyledons!have!completely!unfolded,!the!
aerial!development!of!the!plant!begins.!!Peanut!seedlings!typically!come!through!the!
soil!surface!10!DAP!(American!Peanut!Council!2011).!!Shortly!after!emergence,!the!
plant!begins!to!branch!through!the!formation!of!vegetative!side!shoots.!!RunnerI!and!
VirginiaItype!plants!follow!an!alternate!branching!pattern!(Munger!1998).!!Elongation!
of!the!main!stem!occurs!simultaneously!to!the!development!of!reproductive!and!
vegetative!side!shoots.!!Leaflets!on!the!main!stem!differ!in!size!and!shape!from!those!
found!on!the!lateral!branches!(Stalker!1997).!!Peanuts!grow!into!green!ovalIleafed!
plants!that!are!approximately!45!cm!tall!(American!Peanut!Council!2011).!!!
The!flowering!period!of!the!peanut!plant!is!relatively!long,!as!most!cultivars!
possess!an!indeterminate!growth!pattern!(Munger!1998).!!An!indeterminate!growth!
pattern!is!one!in!which!the!plant!does!not!produce!ovaries!all!at!the!same!time!so!the!
fruits!produced!mature!at!different!rates.!!The!time!from!germination!to!flowering!is!
dependent!on!variety!and!cultivar!although!it!is!typically!initiated!30I40!days!after!
planting!(Figure!3).!
!
Flowering!continues!until!late!in!the!growing!season,!typically!90I120!DAP,!
while!a!decrease!in!the!number!of!flowers!produced!per!day!is!observed!as!seeds!
mature!(Stalker!1997).!!SelfI!fertilization!usually!occurs!within!2!days!after!pollination!
(Stalker!1997,!Munger!1998).!!Following!selfIpollination,!the!petals!of!the!flower!
desiccate!as!the!ovary!begins!to!enlarge!(Munger!1998).!!The!budding!ovary,!better!
known!as!a!“peg”!grows!toward!the!soil!on!a!vine!slightly!away!from!the!axis!of!the!
vegetative!branch!from!which!it!arose!and!penetrates!the!soil!if!the!peg!has!not!formed!
too!far!above!the!soil!line!(Figure!4)!(American!Peanut!Council!2011).!
!
The!ovules!do!not!begin!to!grow!in!size!until!the!peg!penetrates!the!soil!where!
fruit!development!commences!(Pattee!1987).!!The!gynophore!(peg)!is!responsible!for!
pushing!the!ovary!into!the!ground!where!it!develops!into!pod!and!seed!(Pickett!1950).!!
The!peg!ceases!to!elongate!within!a!day!or!two!following!soil!penetration!at!which!point!
more!fully!developed!pods!begin!the!process!of!pod!filling!(Munger!1998).!!Pods!may!
develop!2I5!seeds.!!The!seeds!may!be!round!or!elliptical,!have!pointed!or!flattened!ends,!
and!range!in!color!from!white!to!dark!purple!(Stalker!1997).!!The!main!fruit!growth!
phase!of!peanuts!occurs!in!parallel!with!the!filling!phase!of!additional!fruits!on!the!
plant.!!Due!to!their!indeterminate!growth!pattern!as!well!as!the!relationship!between!
the!number!of!pods!on!a!plant!and!the!amount!of!rainfall!during!the!season,!peanut!
fruits!do!not!ripen!simultaneously!(Figure!5)!(Stalker!1997).!!!
!
The!indeterminate!nature!of!the!peanut!plant!leads!to!difficulty!in!using!planting!
date!as!a!metric!to!determine!the!exact!stage!of!development!of!the!fruits!(Pickett!
1950).!!Research!has!shown!that!most!Virginia!and!runner!type!cultivars!mature!within!
130!I!140!or!more!days!after!planting,!with!some!Spanish!and!Valencia!cultivars!
requiring!only!95!–!100!days!(Henning!1982).!!At!harvest,!pods!may!appear!to!be!the!
same!size;!however,!they!may!possess!significantly!different!maturities!and!seed!
weights!(Stalker!1997).!!Changes!in!pod!structure!allow!ripeness!to!be!characterized!by!
a!pericarp!that!is!hard,!clearly!structured,!and!easily!opened.!!Additionally,!it!has!been!
suggested!that!maturity!may!be!best!determined!through!a!combined!evaluation!of!
kernel!texture,!color,!tightness!of!the!kernel!in!the!hull,!degree!of!parenchymal!tissue!
within!the!pod,!and!change!of!color!on!the!inner!side!of!the!hull!(Figure!6)!(Pattee!
Physiology'
Seed!development!does!not!become!a!dominant!process!until!midway!through!
the!maturation!of!the!fruit!(Pattee!1974).!!As!the!peanut!matures,!physiological!and!
structural!changes!occur!that!impact!the!processing!quality!as!well!as!the!value!of!the!
crop!(Young!2004).!!The!differences!observed!between!fresh!weights!of!immature!and!
mature!seeds!are!due!almost!entirely!to!moisture!content!(Pattee!1974).!!Peanut!seeds!
are!often!classified!as!very!immature,!immature,!mature,!and!very!mature!(Young!
2004).!!As!the!seeds!progress!from!very!immature!to!very!mature,!the!cytoplasmic!
network!as!well!as!the!synthesis!of!storage!substances!in!parenchymal!cells!is!impacted.!!
Parenchymal!cells!are!the!thinIwalled!cells,!which!make!up!the!primary!tissues!of!the!
plant.!!Very!immature!peanuts!are!actively!synthesizing!large!amounts!of!lipid!and!
starch!and!a!much!smaller!amount!of!protein!(Young!2004).!!The!ability!of!the!peanut!to!
accumulate!protein!stores!during!development!is!mainly!dependent!on!the!availability!
and!uptake!of!nitrogen!(Weber!2005).!!Seeds!classified!as!“immature”!have!a!very!large!
amount!of!lipid!however!their!starch!synthesis!is!markedly!less!than!the!“very!
immature”!peanut.!!Starch!accumulation!happens!earliest!in!the!pericarp,!then!the!seed!
coat,!and!reaches!a!constant!level!in!the!seed!near!midImaturity!(Ketring!1982).!!It!
appears!that!starch!is!only!stored!rapidly!during!early!stages!of!maturity!before!
accumulation!of!lipid,!the!final!major!energy!reserve,!becomes!greater!(Pattee!1974).!!
Once!the!seed!is!classified!as!“mature”!and!“very!mature”!the!synthesis!of!lipid,!starch!
of!the!seed!decrease!as!the!seed!develops!(Pickett!1950).!!Additionally,!as!the!seed!
matures,!the!fatIcarbohydrate!and!the!proteinIcarbohydrate!ratios!increase.!!This!
indicates!that!the!fat!increases!in!the!seed!at!the!expense!of!the!carbohydrate!content!
(Pickett!1950).!
!
Oil'synthesis''
Lipid!synthesis!has!been!described!as!a!continuous!process!during!the!early!
stages!of!peanut!seed!development.!!Fatty!acid!synthesis!occurs!in!the!plastid!and!is!
regulated!by!two!enzyme!systems.!!These!are!acetylICoA!carboxylase!and!fatty!acid!
synthase!(Ohlrogge!1997).!!Lipid!begins!to!accumulate!during!the!early!stages!of!seed!
development!but!does!not!reach!its!maximum!levels!until!late!seed!maturity!(Ketring!
1982).!!McNair!has!noted!that!several!factors!such!as!stage!of!development,!heredity,!
and!environment,!along!with!others!impact!lipid!production!(McNair!1945).!!As!an!
example,!the!lower!temperatures!usually!observed!during!the!phase!of!the!peanut!life!
cycle!that!encompasses!seed!development!are!typically!associated!with!a!more!
unsaturated!peanut!oil!due!to!the!increased!activity!of!oleate!desaturase,!an!enzyme!
that!promotes!the!synthesis!of!linoleic!acid!(Andersen!2002,!Carrin!2010).!!This!
relationship!indicates!that!those!peanuts!grown!in!colder!climates!or!those!that!
experience!colder!temperatures!during!the!end!of!the!growing!season!possess!lower!
concentration!increases!and!linoleic!acid!decreases!as!the!seed!matures!with!the!largest!
changes!in!oil!composition!occurring!at!early!stages!of!maturity!(Carrin!2010!and!
Moore!1990).!!Mature!seed!contain!a!larger!proportion!of!stearic!and!oleic!acid!and!less!
arachidic,!behenic!and!lignoceric!acid!than!immature!seed!(Ahmed!1982).!!!
!
Many!physiological!components!of!interest!exist!within!the!lipid!fraction!of!the!
peanut!seed.!!These!include!polyphenols,!tocopherols,!and!phytosterols.!!The!
aforementioned!bioactive!compounds!are!associated!with!health!benefits!making!them!
of!interest!to!the!greater!community!(Jonnala!2006).!
!
Many!of!the!bioactive!compounds!inherent!in!nuts!are!found!in!the!oil!fraction,!
including!tocopherols!in!peanuts!(Jonnala!2009).!!Peanuts!are!a!good!source!of!
tocopherols!being!highest!in!αI!and!γItocopherols!(Jonnala!2006!and!Kornsteiner!
2006).!!All!tocopherols!consist!of!a!chromanol!head!group!and!a!prenyl!side!chain!
(MunneIBosch!2002).!!Tocopherols!vary!from!one!another!only!in!the!placement!and!
number!of!methyl!substituents!on!the!aromatic!ring!(DellaPenna!2006).!!In!Virginia!
type!peanuts,!αItocopherol!levels!have!been!shown!to!decrease!while!γItocopherol!
levels!have!been!shown!to!increase!as!the!seed!matures!(Hashim!1993).!!HighIoleic!oils!
have!also!been!shown!to!possess!increased!levels!of!tocopherols!(Davis!2008).!!
Although!each!varies!in!its!specific!potency!and!function,!tocopherols!act!to!slow!or!
prevalence!of!αItocopherols!is!of!significance!as!it!has!been!shown!to!be!the!most!active!
vitamin!E!precursor!in!humans!(Kornsteiner!2013).!!Additionally,!tocopherols!have!
been!shown!to!protect!seedIstorage!lipids!from!oxidation!during!dormancy!and!
germination!(Della!Penna!2006).!!The!protective!role!against!oxidation!during!
dormancy!and!germination!is!the!only!demonstrated!function!of!these!compounds!
within!the!plant!itself!(DellaPenna!2006).!!!
!
In!terms!of!phystosterols,!βIsitosterol!is!the!major!compound!while!campesterol!
and!stigmasterol!are!also!present!(Jonnala!2006).!!βIsitosterol!comprises!>60%!of!the!
phytosterol!content!of!the!peanut!(Shin!2010).!!It!has!been!demonstrated!that!certain!
physiological!processes!such!as!plant!growth!are!regulated!by!the!presence!of!specific!
sterols!or!sterol!combinations!(Heupel!1986!and!Piironen!2000).!!Free!sterols!play!a!
critical!role!in!the!structure!and!function!of!plant!cell!membranes!(Piironen!2000).!!
Phytosterols!have!chemical!structures!similar!to!cholesterol!with!the!difference!being!
the!configuration!of!the!side!chain!(Piironen!2000).!!These!compounds!are!made!up!of!a!
tetracyclic!cyclopenta[α]phenanthrene!ring!with!a!long!flexible!side!chain!at!the!C17!
carbon.!!Due!to!their!structure,!sterols!are!amphiphilic!and!are!typically!found!in!the!
plasma!membrane!and!largely!determine!its!properties!(Piironen!2000).!!Additionally,!
phytosterols!play!a!role!in!the!differentiation!and!proliferation!of!cells.!!It!has!been!
suggested!that!they!accumulate!in!seeds!and!oils!to!serve!as!a!reservoir!for!new!cell!
their!concentration!decreases!as!seed!maturity!progresses!(Piironen!2000).!!Their!
synthesis!is!the!result!of!the!isoprenoid!biosynthetic!pathway!(Figure!7)!(Piironen!
2000).!
'
HIGHKOLEIC'PEANUTS'
Development'
! In!peanuts,!oleic!and!linoleic!acid!comprise!approximately!80%!of!the!fatty!acid!
content!(Norden!1987).!!The!known!genetic!range!of!fatty!acid!compositions!in!peanuts!
is!41I67%!oleic!acid!and!14I42%!linoleic!(O’Keefe!1993,!Davis!2008).!!Norden!et'al.''
was!the!first!to!identify!peanut!lines!having!highIoleic,!low!linoleic!levels!(1987).!!The!
incorporation!of!highIoleic!genes!into!peanut!breeding!lines!has!resulted!in!highIoleic!
cultivars!that!are!able!to!produce!oil!with!extended!shelf!life!(Carrin!2010).!!These!highI
oleic!cultivars!have!an!oleic!acid!content!greater!than!74%!and!a!linoleic!acid!content!
less!than!10%!(Barkley!2010).!!It!has!been!suggested!that!the!differences!in!relative!
rates!of!synthesis!and!metabolism!of!oleate!are!responsible!for!the!differences!in!fatty!
acid!composition!(Norden!1987).!!!
!
Genetic!manipulation!and!traditional!backcross!breeding!techniques!have!been!
crucial!in!achieving!improvements!of!peanut!cultivars!and!their!oils!(Carrin!2010,!Davis!
ol1!and!Ol2Gol2!through!simple!inheritance!(Barkley!2013,!Moore!1990,!and!Pattee! 2002).!!As!investigation!into!the!genetic!control!of!this!trait!has!progressed,!it!has!been!
shown!that!the!highIoleic!phenotype!is!controlled!by!homozygous!recessive!mutations!
in!the!homeologous!loci!ahFAD2A'and!ahFAD2B'(Barkley!2013).!!These!homeologous!
loci!encode!the!Δ12!fatty!acid!desaturase!2!(FAD2)!gene!which!is!responsible!for!
catalysis!of!the!conversion!of!oleic!acid!to!linoleic!acid!in!the!peanut!seed!(Figure!8)!
(Barkley!2013,!Moore!1990,!Wang!2011).!!Two!mutations!have!been!identified!in!the!
FAD2!genes!and!cultivars!with!one!or!both!mutations!have!been!shown!to!have!the!
highest!O/L!ratios!(Wang!2011).!!Breeding!efforts!have!indicated!that!nonIhighIoleic!
plants!have!a!measurable!range!of!values!of!O/L!ratios!indicating!that!a!polymorphism!
exists!within!the!dominant!alleles!Ol1'and!Ol2!(Isleib!2006a).!!Isleib!et'al.'also! demonstrated!that!the!highIoleate!trait!is!not!completely!recessive!(Isleib!2006a).!!!
!
Advantages'over'traditional'cultivars'
! The!physical!and!chemical!properties!of!fatty!acids!tend!to!dictate!the!properties!
of!an!oil!(Norden!1987).!!Fatty!acid!composition!of!a!peanut!is!influenced!by!its!cultivar,!
maturity!stage!and!the!environmental!conditions!in!which!it!is!grown!(Ahmed!1982).!!
The!ratio!of!oleic!to!linoleic!fatty!acids!has!been!used!as!an!indicator!of!oil!stability!as!
the!polyunsaturated!fatty!acids!present!in!peanuts!cause!them!to!be!susceptible!to!lipid!
to!be!the!major!cause!of!shelf!life!deterioration!and!development!of!offIflavors!and!
aromas!in!roasted!peanut!products!(Bolton!2002,!Isleib!2006b,!and!Wilkin!2012).!!
Oxidative!stability!of!highIoleic!peanut!oil!has!been!shown!to!be!much!better!than!that!
of!normalIoleic!peanut!oil!(O’Keefe!1993).!!Additionally,!the!native!antioxidants!present!
in!highIoleic!cultivars!have!been!shown!to!be!more!stable!during!storage!than!their!
traditional!counterparts!(Wilkin!2012).!!Increased!stability!is!attributed!to!the!
reduction!of!the!total!number!of!double!bonds!seen!in!these!oils!as!compared!to!
traditional!cultivars!(Davis!2008).!!Oils!high!in!oleic!acid!are!also!nutritionally!beneficial!
due!to!their!implications!in!maintaining!heart!health!(Barkley!2010).!!Additionally,!the!
highIoleic!trait!has!been!shown!to!have!a!positive!effect!on!the!intensity!of!the!roasted!
peanut!attribute!(Isleib!2006b).!
!
Importance'to'industry'
! A!major!concern!for!the!multibillionIdollar!per!year!peanut!industry!is!lipid!
oxidation!and!the!production!of!its!characteristic!offIflavors!in!peanut!products!(Bolton!
2002).!!Lipid!oxidation!results!in!the!production!of!volatile!aldehydes,!ketones,!
hydrocarbons!and!alcohols!that!are!undesirable.!!The!process!of!lipid!oxidation,!a!multiI
step!reaction!process!is!depicted!in!Figure!9.!!The!lipid!oxidation!reaction!occurs!
between!fatty!acids!and!oxygen!resulting!in!the!formation!of!a!free!radical.!!Free!radical!
oxidation!is!the!reaction!of!an!alkyl!radical!with!triplet!oxygen,!which!forms!a!peroxyl!
radical.!!The!peroxyl!radical!reacts!with!another!carbon!–!hydrogen!bond!which!leads!to!
the!formation!of!another!radical!and!a!hydroperoxide.!!This!reaction!continues!until!
termination!where!nonIradical!products!are!formed.!!Lipid!oxidation!is!controlled!by!
many!factors!including!the!type!of!fatty!acid!involved.!!Polyunsaturated!fatty!acids!are!
more!prone!to!lipid!oxidation!than!monosaturated!counterparts.!!The!double!bonds!
present!in!unsaturated!fatty!acids!serve!as!a!reaction!site!for!lipid!oxidation.!!Extending!
flavor!stability!of!the!peanut!during!storage!would!benefit!both!processors!and!
consumers!of!peanut!products!by!decreasing!losses!from!lipid!degradation!in!value!
added!products!(Braddock!1995).!!Studies!have!concluded!that!peanuts!with!higher!
oleic!to!linoleic!ratios!demonstrate!less!rancidity!and!are!more!shelfI!stable!than!their!
traditional!counterparts!due!to!their!increased!saturation!(Bolton!2002,!Carrin!2010).!
!
HARVEST'AND'POSTKHARVEST'OPERATIONS'
Harvesting'and'Curing'
Harvesting!involves!all!of!the!processes!required!to!remove!the!peanuts!from!the!
ground!and!separate!them!from!the!soil!and!vine.!!Typically,!these!processes!include!
field!preparation,!vine!clipping,!digging,!shaking,!windrowing,!and!combining!(Young!
1982).!!Peanut!harvesting!takes!place!in!two!phases,!digging!and!threshing,!or!
indeterminate!and!will!continue!to!produce!pods!as!long!as!it!remains!healthy,!
harvesting!must!occur!at!the!correct!point!such!that!field!losses!are!minimal.!!Digging,!
the!first!stage!of!harvesting,!takes!place!when!approximately!70%!of!the!pods!have!
reached!maturity!(American!Peanut!Council!2011).!!In!the!digging!process,!a!digger!
moves!along!the!plant!rows!and!drives!a!horizontal!blade!10I15!cm!below!the!soil!
surface!which!loosens!the!soil!and!cuts!the!tap!root!of!the!plant!(Figure!10)!(American!
Peanut!Council!2011).!
!
Behind!the!digger!blade,!a!shaker!picks!up!the!plants!and!removes!the!dirt!from!
them.!!The!shaker!then!rotates!the!plants,!peanuts!up,!leaves!down!and!places!them!
back!onto!the!ground!in!windrows!(Figure!11).!!Windrows!are!utilized!to!dry!down!the!
peanuts!from!their!20I25%!moisture!content!after!digging.!!This!process!is!known!as!
curing!in!which!the!moisture!content!of!peanuts!is!reduced!to!a!level!that!allows!for!the!
maintenance!of!quality!(Young!1982).!
!
! Peanut!curing!has!been!designed!to!produce!seed!that!do!not!skin!or!split!
excessively!during!shelling!and!which!have!acceptable!flavor.!!The!curing!process!is!
typically!accomplished!in!two!stages.!!The!first!stage!is!comprised!of!field!drying!
completely!or!to!a!20!to!25%!wetIbasis!moisture!content.!!Once!the!peanuts!have!
reached!the!appropriate!moisture!content,!threshing!or!combining!takes!place.!!During!
separates!them!from!the!vine!(American!Peanut!Council!2011).!!The!peanuts!are!blown!
into!a!hopper!while!the!vines!are!spread!back!into!the!field!(Figure!12).!
!
Following!combining,!the!second!stage!of!the!curing!process!takes!place.!!During!
the!second!stage!of!curing,!drying!wagons!are!used!to!slowly!circulate!forced!hot!air!
through!the!freshly!harvested!pods!to!obtain!8!to!10%!wetIbasis!moisture!content!
(Figure!13)!(Young!1982).!!If!the!moisture!content!is!not!sufficiently!reduced,!the!
quality!of!the!peanuts!may!significantly!suffer!due!to!biological!activity!including!mold!
growth!and!mycotoxin!contamination!(Young!1982).!!!
!
Warehouse'Storage'
Farmers!typically!sell!their!peanut!crop!to!buying!points,!which!in!turn!store!the!
peanuts.!!Peanuts!may!be!precleaned!before!storage.!!Precleaning!facilities!typically!
consist!of!a!dump!pit,!cradle!hoist,!precleaner,!elevators,!and!a!shed!or!building!to!
enclose!the!equipment.!!The!precleaning!process!involves!dumping!the!peanuts!from!
the!tractor!trailer!into!the!dump!pit.!!The!peanuts!are!then!lifted!from!the!dump!pit!onto!
a!conveyor!that!will!take!them!through!the!precleaner.!!After!cleaning,!the!peanuts!will!
be!transferred!into!a!storage!unit!(Davidson!1982).!!Peanuts!are!best!stored!at!
approximately!7.5%!kernel!wet!basis!moisture!content!and!at!10!degrees!C!(Smith!
The!shelling!process!includes!precleaning,!presizing,!shelling,!separation,!
sorting,!seed!treatment,!handling,!and!packaging!(Figure!14)!(Davidson!1982).!!
Commercially!shelled!peanuts!are!usually!handled!in!bulk!as!large!cartons!or!bags!
(Figure!15).!!It!is!very!difficult!to!sample!shelled!peanuts!without!splitting!some!of!the!
seed!and!negatively!affecting!their!grade!(Davidson!1982).!!Peanuts!are!usually!
sampled!for!various!attributes!using!inIline!samplers!(Figure!16)(Davidson!1982).!!!
'
Methods'for'Evaluating'Oil'Content'
Oil!content!and!composition!are!important!factors!in!peanut!processing!because!
they!dictate!what!type!of!product!the!peanuts!should!be!incorporated!into!(Sundaram!
2010).!!Additionally,!the!fatty!acid!profile!of!peanuts!is!used!as!an!important!quality!
measure.!!Currently!the!oil!content!and!fatty!acid!profile!of!peanuts!are!evaluated!using!
multiple!methods!including:!nearIinfrared!spectroscopy!(NIR),!refractive!index!(RI),!
and!gas!chromatography!(GC).!!Methods!for!evaluating!oil!content!vary!in!the!amount!of!
skill!required!to!perform!the!analysis,!the!destructive!nature!of!the!method,!and!the!
cost.!!As!a!result,!these!factors!must!be!taken!into!account!prior!to!beginning!evaluation!
of!a!group!of!samples.!!Many!investigators!have!used!GC!for!profiling!peanut!fatty!acids!
because!it!is!efficient!and!the!most!precise!method!for!this!process!(Sundaram!2010).!!!
Determination!of!the!fatty!acid!profile!utilizing!GC!is!often!done!utilizing!the!fatty!
peanut!is!derivitized!with!methanolic!potassium!hydroxide!and!esterified!with!boron!
trifluoride!(BF3).!!The!methylated!fatty!acids!are!then!separated!utilizing!capillary!GC!
equipped!with!a!flame!ionization!detector.!!Capillary!GC!is!used!because!it!provides!for!
efficient!and!selective!separation!of!samples!(Skoog!2007).!!Gas!chromatography!is!a!
physical!method!of!separation!based!upon!the!selective!interaction!of!sample!
components!within!the!carrier!gas!with!the!stationary!phase!(Poole!2003).!!Individual!
sample!components!have!different!partition!coefficients,!which!allow!for!successful!
separation!as!they!elute!from!the!column!at!different!times.!!The!time!it!takes!for!a!
compound!to!elute!from!the!column!is!known!as!retention!time.!!The!retention!time!of!a!
given!compound!is!determined!based!upon!its!interaction!with!the!stationary!phase.!!
Compounds!with!the!most!affinity!for!the!stationary!phase!have!the!longest!retention!
times.!!Retention!time!is!utilized!to!identify!peaks!in!a!chromatogram.!!Peak!area!is!
utilized!to!determine!the!amount!of!given!compound!present!in!a!sample.!!Flame!
ionization!detection!is!the!most!common!type!of!detection!in!modern!GC.!!When!this!
type!of!detector!is!utilized,!effluent!from!column!is!directed!into!a!hydrogenIair!flame!
where!the!detector!monitors!the!current!produced!by!collecting!the!ions!and!electrons!
that!result!from!burning!of!the!effluent!(Skoog!2007).!!Additionally,!GC!–FID!is!highly!
sensitive!and!produces!low!noise.!!This!procedure!is!most!useful!for!the!analysis!of!
samples!containing!mainly!fatty!acids!greater!than!C12!(Bannon!1982).!!A!major!
sample!is!destroyed.!!Although!it!is!highly!sensitive,!the!destructive!nature!of!GC!makes!
it!difficult!to!use!in!a!processing!environment.!!!
!
!In!addition!to!the!traditional!GC!method,!newer!methods!using!NIR!have!been!
developed.!!NIR!is!a!rapid,!nondestructive!method!that!provides!information!about!the!
components!present!in!the!peanut!(Sundaram!2010).!!This!method!determines!oil,!
protein,!and!moisture!content!of!the!sample!by!deducing!CIH,!NIH,!and!OIH!bonds!
(Sundaram!2010).!!It!uses!absorbance!at!wavelengths!from!13000!to!4000!cmI1!detect!
the!overtones!of!stretching!vibrations!that!occur!in!the!3000!to!1700!cmI1!region!(Skoog!
2007).!!NIR!has!been!used!since!it!allows!for!quantitative!determination!of!various!
components!such!as!fatty!acids.!!Unlike!the!distinct!peaks!observed!in!GCIFID!
chromatograms,!the!spectral!bands!generated!using!NIR!are!often!broad!and!
overlapping!requiring!the!use!of!calibration!techniques,!such!as!least!squares,!to!
determine!the!quantity!of!the!component!present!(Skoog!2007).!!!!
!
The!refractive!index!of!a!material!is!the!speed!of!light!in!a!vacuum!compared!to!
the!speed!of!light!through!a!given!material.!!As!such,!it!can!be!utilized!to!characterize!
various!properties!of!a!material.!!RI!is!also!utilized!for!determination!of!fatty!acid!
content!in!the!peanut!as!described!by!Davis!et'al'(2013).''It!has!been!shown!that!as!the!
amount!of!unsaturated!fatty!acids!increases,!the!RI!of!the!oil!will!increase!as!well!(Davis!
bends!when!passing!through!a!sample!(Skoog!2007).!!RI!is!a!rapid!method!for!
measuring!the!O/L!ratio!in!peanut!lots!(Davis!2013).!!A!drawback!to!RI!for!determining!
O/L!ratios!in!peanut!lots!is!that!it!requires!the!oil!to!be!removed!from!the!seed!making!
it!a!destructive!method!of!analysis.!
'
RESEARCH'OBJECTIVE'
The!goal!of!this!research!is!to!understand!how!the!total!fat!and!lipid!composition!
of!the!peanut!fruit!changes!as!the!seed!matures!as!well!as!to!investigate!what!other!
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Figure!1.!Peanut!producing!regions!of!the!U.S.A.!(American!Peanut!Council!2011)!
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REFERENCES'
Ahmed,!E.!M.,!&!Young,!C.!T.!(1982).!Composition,!quality,!and!flavor!of!peanuts.!In!H.!E.! Patee,!&!C.!T.!Young!(Eds.),!Peanut'Science'and'Technology!(pp.!655J688).!Yoakum,! Texas:!American!Peanut!Research!and!Education!Society,!Inc.!!
American!Peanut!Council!(2011).!About!the!peanut!industry.!!Retrieved!from!
http://www.peanutsusa.com/images/phocadownload/WebDocsGeneral/USA%20 Peanuts%20Growing%20and%20Harvesting%20FINAL.pdf!
Andersen,!P.!C.,!&!Gorbet,!D.!W.!(2002).!Influence!of!year!and!planting!date!on!fatty!acid! chemistry!of!highJoleic!acid!and!normal!peanut!genotypes.'Journal'of'Agricultural' and'Food'Chemistry,'50(5),!1298J1305.!!
Bannon,!C.!D.,!Craske,!J.!D.,!Hai,!N.!T.,!Harper,!N.!L.,!&!O'Rourke,!K.!L.!(1982).!Analysis!of! fatty!acid!methyl!esters!with!high!accuracy!and!reliability!:!II.!methylation!of!fats! and!oils!with!boron!trifluorideJmethanol.'Journal'of'Chromatography'A,'247(1),!63J 69.!!
Barkley,!N.!A.,!Chamberlin!Chenault,!K.!D.,!Wang,!M.!L.,!&!Pittman,!R.,!N.!(2010).! Development!of!a!realJtime!PCR!genotyping!assay!to!identify!highJoleic!acid! peanuts!(arachis'hypogaea!L.).'Molecular'Breeding,'25(3),!541J548.!!
Barkley,!N.,!Isleib,!T.,!Wang,!M.,!&!Pittman,!R.!(2013).!Genotypic!effect!of!ahFAD2!on! fatty!acid!profiles!in!six!segregating!peanut!(arachis!hypogaea!L)!populations.'BMC' Genetics,'14(1),!62.!!
Bolton,!G.!E.,!&!Sanders,!T.!H.!(2002).!Effect!of!roasting!oil!composition!on!the!stability! of!roasted!highJoleic!peanuts.'Journal'of'the'American'Oil'Chemists'Society,'79(2),! 129J132.!!
Braddock,!J.!C.,!Sims,!C.!A.,!&!O'Keefe,!S.!F.!(1995).!Flavor!and!oxidative!stability!of! roasted!highJoleic!acid!peanuts.'Journal'of'Food'Science,'60(3),!489J493.!!
Bradley,!A.!(2012).!Peanut!maturity!is!early.!Retrieved!from!
http://edgecombe.ces.ncsu.edu/2012/09/peanutJmaturityJisJearly/!!
Davidson,!J.!I.!J.,!Whitaker,!T.!B.,!&!Dickens,!J.!W.!(1982).!Grading,!cleaning,!storage,! shelling,!and!marketing!of!peanuts!in!the!united!states.!In!H.!E.!Pattee,!&!C.!T.!Young! (Eds.),!Peanut'Science'and'Technology!(pp.!571J623).!Yoakum,!TX:!American!Peanut! Research!and!Education!Society,!Inc.!!
Davis,!J.!P.,!Dean,!L.!O.,!Faircloth,!W.!H.,!&!Sanders,!T.!H.!(2008).!Physical!and!chemical! characterizations!of!normal!and!highJoleic!oils!from!nine!commercial!cultivars!of! peanut.'Journal'of'the'American'Oil'Chemists'Society,'85(3),!235J243.!!
Davis,!J.,!Sweigart,!D.,!Price,!K.,!Dean,!L.,!&!Sanders,!T.!(2013).!Refractive!index!and! density!measurements!of!peanut!oil!for!determining!oleic!and!linoleic!acid! contents.'Journal'of'the'American'Oil'Chemists''Society,'90(2),!199J206.!!
DellaPenna,!D.!&!Pogson,!B.J.!(2006).!Vitamin!synthesis!in!plants:!tocopherols!and! carotenoids.!Annual'Review'of'Plant'Biology,!57,!711J738.!
Hashim,!I.!B.,!Koehler,!P.!E.,!&!and!Eitenmiller,!R.!R.!(1993).!Tocopherols!in!runner!and! virginia!peanut!cultivars!at!various!maturity!stages.'Journal'of'the'American'Oil' Chemists'Society,'70(6),!633J635.!!
Henning,!R.!J.,!Allison,!A.!H.,!&!Tripp,!L.!L.!(1982).!Cultural!practices.!In!H.!E.!Pattee,!&!C.! T.!Young!(Eds.),!Peanut'Science'and'Technology!(pp.!123J138).!Yoakum,!Texas:! American!Peanut!Research!and!Education!Society,!Inc.!
Heupel,!R.,!Sauvaire,!Y.,!Le,!P.,!Parish,!E.,!&!Nes,!W.!D.!(1986).!Sterol!composition!and! biosynthesis!in!sorghum:!Importance!to!developmental!regulation.'Lipids,'21(1),! 69J75.!!
Holaday,!C.!E.,!Williams,!E.!J.,!&!Chew,!V.!(1979).!A!method!for!estimating!peanut! maturity.'Journal'of'Food'Science,'44(1),!254J256.!!
Isleib,!T.!G.,!Wilson,!R.!F.,!&!Novitzky,!W.!P.!(2006a).!Partial!dominance,!pleiotropism,! and!epistasis!in!the!inheritance!of!the!highJoleate!trait!in!peanut.'Crop'Science,' 46(3),!1331J1335.!!
Isleib,!T.!G.,!Pattee,!H.!E.,!Sanders,!T.!H.,!Hendrix,!K.!W.,!&!Dean,!L.!O.!(2006b).!
Compositional!and!sensory!comparisons!between!normalJ!and!highJoleic!peanuts.' Journal'of'Agricultural'and'Food'Chemistry,'54(5),!1759J1763.!!
Jonnala,!R.!S.,!Dunford,!N.!T.,!&!Dashiell,!K.!E.!(2005).!New!highJoleic!peanut!cultivars! grown!in!the!southwestern!united!states.'Journal'of'the'American'Oil'Chemists' Society,'82(2),!125J128.!!
Jonnala,!R.!S.,!Dunford,!N.!T.,!&!Dashiell,!K.!E.!(2006).!Tocopherol,!phytosterol!and! phospholipid!compositions!of!new!highJoleic!peanut!cultivars.'Journal'of'Food' Composition'and'Analysis,'19(6J7),!601J605.!!
Ketring,!D.!L.,!Brown,!R.!H.,!Sullivan,!G.!A.,!&!Johnson,!B.!B.!(1982).!Growth!physiology.!In! H.!E.!Pattee,!&!C.!T.!Young!(Eds.),!Peanut'Science'and'Technology!(pp.!411J457).! Yoakum,!TX:!American!Peanut!Research!and!Education!Society,!Inc.!!
Kornsteiner,!M.,!Wagner,!K.,!&!Elmadfa,!I.!(2006).!Tocopherols!and!total!phenolics!in!10! different!nut!types.'Food'Chemistry,'98(2),!381J387.!!
Maiti,!R.!K.!(2002).!About!the!peanut!crop.!In!R.!Maiti,!&!P.!WescheJEbeling!(Eds.),!The' Peanut'(Arachis'hypogaea)'Crop!(pp.!1J12).!Enfield,!NH:!Science!Publishers.!!
Marsalis,!M.!A.,!Puppala,!N.,!Goldberg,!N.!P.,!Ashigh,!J.,!Sanogo,!S.,!&!Trostle,!C.!(2009).! New!mexico!peanut!production.'New'Mexico'State'University'Cooperative'Extension' Service'Circular,'(645),!1J16.!!
McNair,!J.!B.!(1945).!Plant!fats!in!relation!to!environment!and!evolution.'Botanical' Review,'11(1),!1J59.!!
Moore,!K.!M.!(1990).!Genetic,'developmental,'and'molecular'characterization'of'a'highU oleic'acid'peanut'(arachis'hypogaea'L.).'University!of!Florida.!Dissertation.!
Moss,!J.!P.,!&!Rao,!V.!R.!(1995).!The!peanut!J!reproductive!development!to!plant! maturity.!In!H.!E.!Pattee,!&!H.!T.!Stalker!(Eds.),!Advances'in'Peanut'Science!(pp.!1J 13).!Stillwater,!OK:!American!Peanut!Research!and!Education!Society,!Inc.!!
Munger,!P.,!Bleiholder,!H.,!Hack,!H.,!Hess,!M.,!Strauss,!R.,!van!den!Boom,!T.,!&!Weber,!E.! (1998).!Phenological!growth!stages!of!the!peanut!plant!(arachis'hypogaea'L.):! Codification!and!description!according!to!the!BBCH!scale.'Journal'of'Agronomy'and' Crop'Science,'180(2),!101J107.!!
Norden,!A.!J.,!Gorbet,!D.!W.,!Knauft,!D.!A.,!&!Young,!C.!T.!(1987).!Variability!in!oil!quality! among!peanut!genotypes!in!the!Florida!breeding!program.'Peanut'Science,'14(1),!7J 11.!!
Ohlrogge,!J.!B.,!&!Jaworski,!J.!G.!(1997).!Regulation!of!fatty!acid!synthesis.'Annual'Review' of'Plant'Physiology'and'Plant'Molecular'Biology,'48,!109J136.!!
O'Keefe,!S.!F.,!Wiley,!V.!A.,!&!Knauft,!D.!A.!(1993).!Comparison!of!oxidative!stability!of! HighJ!and!normalJoleic!peanut!oils.'Journal'of'the'American'Oil'Chemists'Society,' 70(5),!489J492.!!
Pattee,!H.!E.,!Isleib,!T.!G.,!Moore,!K.!M.,!Gorbet,!D.!W.,!&!Giesbrecht,!F.!G.!(2002).!Effect!of! highJoleic!trait!and!paste!storage!variables!on!sensory!attribute!stability!of!roasted! peanuts.'Journal'of'Agricultural'and'Food'Chemistry,'50(25),!7366J7370.!!
Pattee,!H.!E.,!Johns,!E.!B.,!Singleton,!J.!A.,!&!Sanders,!T.!H.!(1974).!Composition!changes!of! peanut!fruit!parts!during!maturation.'Peanut'Science,'1(2),!57J62.!!
Pattee,!H.!E.,!&!Mohapatra,!S.!C.!(1987).!Anatomical!changes!during!ontogeny!of!the! peanut!(arachis!hypogaea!L.)!fruit:!Mature!megagametophyte!through!heartJ shaped!embryo.'Botanical'Gazette,'148(2),!156J164.!!
Pickett,!T.!A.!(1950).!Composition!of!developing!peanut!seed.'Plant'Physiology,'25(2),! 210J224.!!
Piironen,!V.,!Lindsay,!D.!G.,!Miettinen,!T.!A.,!Toivo,!J.,!&!Lampi,!A.!(2000).!Plant!sterols:! Biosynthesis,!biological!function!and!their!importance!to!human!nutrition.'Journal' of'the'Science'of'Food'and'Agriculture,'80(7),!939J966.!!
Poole,!C.!F.!(2003).!Chapter!1!J!general!concepts!in!column!chromatography.!The' Essence'of'Chromatography!(pp.!1J78).!Amsterdam:!Elsevier!Science.!!
Shin,!E.,!Pegg,!R.!B.,!Phillips,!R.!D.,!&!and!Eitenmiller,!R.!R.!(2010).!Commercial!peanut! (arachis'hypogaea!L.)!cultivars!in!the!United!States:!Phytosterol!composition.' Journal'of'Agricultural'and'Food'Chemistry,'58(16),!9137J9146.!!
Skoog,!D.!A.,!Holler,!F.!J.,!&!Crouch,!S.!R.!(2007).!Principals'of'Instrumental'Analysis!(6th! ed.).!Australia:!Cengage.!!
Smith,!J.!S.!J.,!Blankenship,!P.!D.,!&!McIntosh,!F.!P.!(1995).!Advances!in!peanut!handling,! shelling!and!storage!from!farmer!stock!to!processing.!In!H.!E.!Pattee,!&!H.!T.!Stalker! (Eds.),!Advances'in'Peanut'Science!(pp.!500J527).!Stillwater,!OK:!American!Peanut! Research!and!Education!Society,!Inc.!!
Stalker,!H.!T.!(1997).!Peanut!(arachis'hypogaea'L.)!Field'Crops'Research,'53(1J3),!205J 217.!!
Sundaram,!J.,!Kandala,!C.!V.,!Holser,!R.!A.,!Butts,!C.!L.,!&!Windham,!W.!R.!(2010).!
Determiniation!of!inJshell!peanut!oil!and!fatty!acid!composition!using!nearJinfrared! reflectance!spectroscopy.'Journal'of'the'American'Oil'Chemists'Society,'87(10),! 1103J1114.!!
Wang,!M.!L.,!Barkley,!N.!A.,!Chen,!Z.,!&!Pittman,!R.,!N.!(2011).!FAD2'Gene!mutations! significantly!alter!fatty!acid!profiles!in!cultivated!peanuts!(arachis'hypogaea).' Biochemical'Genetics,'49(11J12),!748J759.!!
Weber,!H.,!Borisjuk,!L.,!&!Wobus,!U.!(2005).!Molecular!physiology!of!legume!seed! development.'Annual'Review'of'Plant'Biology,'56,!253J279.!!
Wilkin,!J.,!Ashton,!I.,!Fielding,!L.,!&!Tatham,!A.!(2012).!Storage!stability!of!whole!and! nibbed,!conventional!and!highJoleic!peanuts!(arachis!hypogeae!L.).'Food'and' Bioprocess'Technology,'7(1),!105J113.!!
Young,!J.!H.,!Person,!N.!K.,!Donald,!J.!O.,!&!Mayfield,!W.!D.!(1982).!Harvesting,!curing!and! energy!utilization.!In!H.!E.!Patee,!&!C.!T.!Young!(Eds.),!Peanut'Science'and'
Technology!(pp.!458J485).!Yoakum,!Texas:!American!Peanut!Research!and! Education!Society,!Inc.!!
Young,!C.!T.,!Pattee,!H.!E.,!Schadel,!W.!E.,!&!Sanders,!T.!H.!(2004).!Microstructure!of! peanut!(arachis!hypogaea!L.!cv.!‘NC!7’)!cotyledons!during!development.'LWT'U'Food' Science'and'Technology,'37(4),!439J445.!!
Zobel,!R.!W.,!&!Waisel,!Y.!(2010).!A!plant!root!system!architectural!taxonomy:!A! framework!for!root!nomenclature.'Plant'Biosystems,'144(2),!507J512.!!
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CHAPTER'3:'THE'IMPACT'OF'NORMAL'PEANUT'DEVELOPMENT'ON'THE'LIPID'
MATERIALS'AND'METHODS' '
Peanut!plants!of!the!VirginiaJtype!cultivars!Spain!(USDAJAMS!Plant!Variety!
Certificate!No.!201200394)!and!Bailey!(Isleib!et'al.!2011)!were!grown!during!the!2012!
season!at!NCSU!Experimental!Station,!Rocky!Mount,!NC.!!The!plots!utilized!had!not!been!
planted!with!peanuts!for!two!years!prior!to!the!study.!!Bailey!seeds!were!planted!22!
May!and!Spain!seeds!were!planted!23!May!2012.!!Plants!were!harvested!beginning!65!
days!after!planting!(DAP)!and!subsequently!on!a!weekly!basis!until!148!DAP.!!
Harvesting!began!65!DAP!as!this!was!the!point!at!which!pod!production!was!first!
observed.!!Following!each!harvest,!pods!were!removed!manually!and!debris!was!
washed!off!using!a!water!hose.!!Samples!were!allowed!to!airJdry!overnight.!!Total!pod!
weights!were!obtained!before!seeds!were!removed.!!Each!pod!was!opened!using!a!razor!
blade!and!the!individual!seeds!were!removed.!!Each!seed!and!the!remaining!pod!
structure!were!assigned!a!unique!number!for!tracking!purposes.!!!Weights!were!
obtained!for!each!individual!seed!before!placing!them!individually!in!plastic!screw!
capped!culture!tubes!for!storage.!!Seeds!were!stored!at!J20°C!prior!to!analysis.!!!
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Determination'of'Fatty'Acid'Profile'
To!determine!the!fatty!acid!profile!of!the!maturing!peanut!seeds,!the!fatty!acid!
modifications.!!A!core!sample!of!each!seed!was!removed!using!a!hollow!needle.!!The!
needle!was!25!mm!long!with!an!interior!opening!of!1!mm.!!Peanut!seeds!were!sampled!
to!obtain!core!samples!amounting!to!~0.10!g!per!seed,!size!permitting.!!In!instances!
where!the!seed!was!too!small!to!be!punched,!the!entire!seed!was!used!for!analysis.!!
(Zeile!1993).!
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Samples!of!~0.1000!g!per!seed!were!weighed!into!glass!screw!topped!culture!
tubes.!!The!first!step!in!the!methylation!process!was!the!addition!of!1mL!0.5M!
methanolic!potassium!hydroxide.!!Methanolic!potassium!hydroxide!was!prepared!by!
weighing!28.14!g!potassium!hydroxide!(KOH)!(Fisher!Scientific,!Pittsburgh,!PA)!into!a!
1000!mL!volumetric!flask.!!The!flask!was!then!filled!halfway!with!methanol!and!stirred!
mechanically!with!a!stir!bar!until!all!solids!dissolved.!!No!heat!was!utilized.!!After!
dissolving,!the!solution!was!diluted!to!volume!with!methanol!and!transferred!to!a!
plastic!screw!capped!bottle!and!stored!at!room!temperature.!!Following!the!addition!of!
methanolic!KOH,!tubes!were!capped!and!heated!for!5!minutes!in!a!water!bath!at!85°C.!!
After!heating,!tubes!were!uncapped!and!allowed!to!cool!slightly!before!1!mL!of!BF3!
(14%!in!methanol)!(Sigma,!St.!Louis,!MO)!was!added.!!Tubes!were!then!capped!and!
heated!for!10!minutes!in!a!water!bath!at!85°C.!!!When!removed!from!the!water!bath,!
tubes!were!uncapped!and!allowed!to!cool!for!approximately!5!minutes!before!the!
addition!of!1!mL!hexane!(Optima!grade,!Fisher).!!This!cooling!step!was!included!to!
of!the!samples.!!After!the!hexane!addition,!samples!were!vortexed!vigorously!for!30!
seconds.!!Saturated!sodium!chloride!(NaCl)!solution!was!added!at!approximately!1J2!
mL!to!each!tube.!!Substitution!of!saturated!NaCl!for!water!was!utilized!to!aid!in!the!
prevention!of!emulsion!formation!due!to!the!high!protein!content!of!the!samples.!!
Samples!were!then!allowed!to!sit!until!distinct!layers!were!visible!in!the!tubes.!!The!
hexane!layer!(top)!was!removed!from!the!sample!tubes!using!a!Pasteur!pipette!and!
placed!into!a!culture!tube!with!a!small!amount!of!sodium!sulfate!(Sigma).!!The!culture!
tube!was!then!swirled!to!remove!any!water!from!the!solvent.!!Once!water!was!removed,!
the!hexane!was!transferred!to!GC!vial!with!a!crimp!top!closure!for!analysis.!
!
The!samples!were!analyzed!on!a!PerkinJElmer!Clarus!500!gas!chromatograph!
(GC)!(Perkin!Elmer!Corp.,!Shelton,!CN)!fitted!with!a!SGE!BPX70!!capillary!column!(30!m!
length,!0.25!mm!i.d.,!0.25!μm!film)!(SGE!Analytical!Science,!Austin,!TX)!and!equipped!
with!a!flame!ionization!detector!(FID)!set!to!265°C.!!The!temperature!program!utilized!
was!as!follows:!60°C!for!2!minutes,!increased!to!180°C!at!10°C/min,!then!increased!to!
235°C!at!4°C/min!with!a!total!run!time!of!27.7!min.!!Helium!at!20!psi!was!used!as!a!
carrier!gas.!!The!injection!was!split!with!a!flow!rate!of!20!mL/min.!KelJFim!FAMEJ5!
Standard!(Matreya!LLC,!Pleasant!Gap,!PA)!and!GLCJ21A!Standard!(NuJCheck!Standards)!
were!utilized!as!standards!to!establish!retention!times.!!Fatty!acid!content!was!
Determination'of'Phytosterol'Content'
To!determine!the!phytosterol!content!of!ground!peanut!samples,!the!method!of!
Maguire'et.'al'was!used!with!minor!modifications.!!Whole!peanut!remainders!from!the!
fatty!acid!analyses!were!ground!using!a!coffee!grinder!(Krups!203!Fast!Touch!Coffee!
Grinder)!and!a!sample!weighing!approximately!0.2500!g!was!taken!and!placed!in!a!
screw!top!culture!tube.!!An!aliquot!of!ethanol!solution!(500!μL)!containing!100!mcg!of!
cholestane!was!added!to!each!tube.!!Then,!300!mcL!of!50%!(w/v)!of!potassium!
hydroxide!in!water!followed!by!1.5!mL!of!1%!pyrogallol!in!ethanol!solution!was!added!
to!each!and!the!tubes!were!capped.!!The!tubes!were!heated!for!30!min!at!70°C!in!a!
water!bath.!!After!cooling!briefly!on!ice,!1!mL!of!water!and!4!mL!of!hexane!were!added!
to!the!tubes.!!The!tubes!were!vortexed!at!full!speed!for!30!sec,!then!allowed!to!stand!to!
form!layers.!!The!top!layer!(hexane)!was!removed!to!a!clean!glass!tube.!!Another!aliquot!
of!2!mL!of!hexane!was!added!to!the!reaction!tube,!vortexed!for!30!seconds!and!the!tube!
was!centrifuged!for!10!min!at!1,000!rpm.!!The!top!layer!was!pooled!with!the!original!
hexane!portion.!!The!hexane!containing!the!sterols!was!then!evaporated!under!a!stream!
of!nitrogen.!!An!aliquot!of!200!∼μL!of!hexane!was!added!to!solubilize!the!residue.!!The!
solution!was!transferred!to!a!vial!and!100!∼μL!of!TriJSil!Reagent!was!added!to!
derivatize!the!phytosterols!in!the!sample!to!their!trimethylsilylesters.!!Samples!were!
then!analyzed!using!a!PerkinJElmer!Clarus!500!gas!chromatograph!(GC)!(Perkin!Elmer!
length!was!30!m!with!an!internal!diameter!of!0.25!mm!and!a!film!thickness!of!0.25!μm.!!
The!temperature!gradient!was!100°C!with!a!0.2!min!hold!time,!increased!at!10°C!per!
min!to!a!final!temperature!of!305°C!with!a!hold!time!of!15!min.!!The!run!time!was!35.7!
min.!!The!carrier!gas!used!was!helium!at!a!flow!rate!of!15!psi.!!The!injection!was!split!at!
70!mL/min.!!Cholestane!internal!standard!was!added!to!an!aliquot!of!Sterol!Standard!
Mix!(Matreya!LLC,!Pleasant!Gap,!PA).!!The!mixture!was!derivatized!as!the!samples!and!
was!used!to!calculate!the!amount!of!each!sterol!in!the!samples!using!Relative!Response!
Factors!(RRF).!!!
!
Genotyping'of'Varieties'
The!genotypic!analysis!of!14!peanut!seeds!was!performed!at!the!USDAJARS!Plant!
Genetic!Resources!Conservation!Unit!(Griffin,!GA).!!The!analysis!was!performed!
according!to!Barkley!et'al.'(2013).!!Slices!from!the!single!seeds!were!used!for!DNA!
extraction.!!DNA!was!extracted!from!the!seed!samples!following!the!instructions!from!
an!OmegaJBiotek!E.Z.N.A!Plant!DNA!kit!(Norcross,!GA.).!!Real!time!PCR!assays!were!
utilized!to!genotype!the!peanuts!for!the!ahFAD2!alleles.!!The!PCR!reactions!were!
performed!using!an!ABI!StepOne™!RealJtime!PCR!machine!using!MicroAmp®!fast!optical!
48Jwell!plate!and!adhesive!film!seals!(Applied!Biosystems,!Foster!City,!CA.).!!The!
genotyping!test!used!picks!up!the!G448A!substitution!in!FAD2A!and!the!A442!insertion!
(Applied!Biosystems)!was!utilized!to!analyze!and!score!the!sample!genotypes.!!Testing!
for!the!MITE!insertion,!the!less!common!mutation!for!highJoleic!trait,!was!not!
performed.!
!
Determination'of'Maturity'Classes'
For!determination!of!maturity,!approximately!7!kg!samples!were!taken!at!the!
final!sampling!date!148!DAP!for!each!cultivar,!Bailey!and!Spain.!!Care!was!taken!to!
ensure!all!peanuts!were!collected!and!none!were!left!in!the!soil.!!Following!collection,!
samples!were!rinsed!in!water!to!remove!soil!and!other!debris.!!The!color!of!the!exposed!
mesocarp!of!the!pod!was!used!to!indicate!seed!maturity!after!the!exocarp!was!removed!
with!a!power!washer.!!In!order!to!protect!very!immature!soft!pods!from!the!power!
washing,!these!pods!were!removed!prior!to!blasting.!!The!power!washer,!equipped!with!
a!turbo!nozzle,!was!used!to!blast!the!pods!inside!a!wire!cage!placed!inside!a!bucket.!!
Drain!holes!cut!in!the!bottom!of!the!bucket!allowed!water!to!escape.!!Pods!were!blasted!
in!batches!of!approximately!2!kg!pods!from!a!height!of!around!12!inches!so!that!the!
exocarp!could!be!removed!without!compromising!the!integrity!of!the!pods.!!!After!pod!
blasting,!pods!were!placed!in!a!cooler!at!40°F!until!the!pods!could!be!sorted!into!the!
color!classes!black,!brown,!orange!B,!orange!A,!yellow!and!white.!!Pods!were!color!
sorted!based!on!the!method!of!Williams!and!Drexler!(1981).!!Tiny!seeds,!less!than!0.01!
Statistical'Analysis'
The!data!were!analyzed!using!SAS!Statistical!Package!9.3!(SAS!Institute,!Cary,!NC).!!
The!MIXED!Procedure!and!the!GLIMMIX!Procedure!were!utilized!for!data!analysis.!!The!
MIXED!procedure!was!used!in!place!of!the!standard!linear!model!GLM!procedure!
because!it!allows!for!the!analysis!of!data!that!exhibit!correlation!and!that!do!not!have!
constant!variability!(SAS!Institute!2014b).!!The!MIXED!procedure!relies!on!the!
assumption!that!the!data!are!normally!distributed!and!as!graphical!analysis!indicated!
that!the!residuals!of!the!data!were!not!normally!distributed,!the!GLIMMIX!procedure!
was!also!utilized.!!The!GLIMMIX!procedure!fits!generalized!linear!mixed!models!to!data!
that!have!correlations,!nonJconstant!variability!or!that!may!not!be!normally!distributed!
(SAS!Institute!2014a).!!!
!
RESULTS'AND'DISCUSSION'
Pod'and'Seed'Development'
The!primary!focus!of!this!work!was!to!investigate!how!O/L!ratio!varied!during!
growth!and!development!in!both!normalJ!and!highJoleic!peanut!cultivars,!To!begin!this!
study,!it!was!necessary!to!carefully!site!and!plant!both!cultivars!(high!and!normal!oleic)!
to!ensure!that!sampled!peanuts!would!be!free!of!contaminating!germplasm!from!
neighboring!fields!or!from!volunteer!plants!leftover!from!previous!growing!seasons!in!
fields!that!had!not!had!peanuts!for!at!least!two!years!prior!to!the!study!and!the!planter!
was!cleaned!before!and!after!planting!each!cultivar!to!ensure!no!contamination!
occurred!there.!!Beginning!when!small!seeds!first!began!to!appear!in!the!pods,!each!
variety!was!sampled!weekly!and!assessed!for!pod!maturity,!pod!weight,!seed!weight,!
moisture!content!and!fatty!acid!profile.!!!Additionally,!100!certified!seed!from!each!
variety!used!for!planting!were!analyzed!using!gas!chromatography!to!determine!their!
O/L!ratio.!!All!Bailey!seeds!(normalJoleic)!analyzed!were!classified!as!normalJoleic!
while!97%!of!Spain!seeds!(highJoleic)!analyzed!were!characterized!as!highJoleic.!!!!
!
In!order!to!clearly!accomplish!the!objective!of!this!study,!it!was!necessary!to!
relate!the!O/L!ratio!to!other!parameters!indicative!of!peanut!development.!!Practically!
speaking,!peanut!size!has!always!been!used!as!a!proxy!for!development!as!it!is!an!easily!
measurable!trait!(Pattee!1977).!!On!a!weekly!basis,!five!plants!from!each!cultivar,!Bailey!
(normalJoleic)!and!Spain!(highJoleic)!were!harvested!and!the!pod!and!seed!weights!
measured.!!Pod!and!seed!weights!were!recorded!beginning!65!days!after!planting!(DAP)!
(27JJulJ12)!and!71!DAP!(1JAugJ12),!respectively,!and!continued!weekly!until!the!final!
measurement!for!pods!and!seeds!of!both!varieties,!which!occurred!148!DAP!(18JOctJ
12).!!Bailey!pod!weights,!seed!weights,!and!seed!weight!as!a!percentage!of!pod!weights!
for!each!week!of!the!study!are!found!in!Figure!1.!!Bailey!pods!grew!to!4!to!5!g!by!71!
DAP.!!!Smaller!pods!constantly!formed!due!to!the!indeterminate!flowering!trait!of!