research article size and charge stability of oil bodies

Research ArticleSize and Charge Stability of Oil Bodies from Peanut

Lihua Hao12 Fusheng Chen12 Yimiao Xia12 Lifen Zhang1 and Ying Xin1

1College of Food Science and Technology Henan University of Technology No 100 Lian Hua Rd Zhengzhou Henan 450001 China2Collaborative Innovation Center of Grain Storage Security in Henan Province Zhengzhou China

Correspondence should be addressed to Fusheng Chen fushengchauteducn

Received 1 November 2016 Revised 29 November 2016 Accepted 30 November 2016

Academic Editor Alexandre Giuliani

Copyright copy 2016 Lihua Hao et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

In order to offer scientific bases for the application of oil bodies from peanut in food this research was undertaken to study thesize and charge stability of oil bodies from five peanut varieties It showed that the mean diameter of oil bodies from yuhua9719and yuhua9830 is obviously larger than yuhua23 yuhua27 and yuhua9502 in the peanut cell Moreover the analysis of diameterdistribution of oil bodies also showed that the median diameter of oil bodies increased dramatically in the order of yuhua9719gt yuhua9830 gt yuhua23 gt yuhua27 gt yuhua9502 after aqueous extraction The charge stability of oil bodies from peanut wasobserved with zeta (120577) potential measurements which indicated that charge properties and the absolute value of oil bodies fromfive peanut varieties were significantly affected by pH and salt concentration but the degree of influence is different Of the fivepeanut varieties yuhua27 and yuhua9830 possessed excellent charge stability (120577-potential gt 35mV) in neutral microenvironmentwithout salt concentration

1 Introduction

Oleaginous plants store lipids in the form of distinct spheri-cal organelles called oil bodies (oleosomes or spherosomes)that serve as energy stores to support active metabolism[1] Each oil body has a neutral lipid matrix core that iscomprised mainly of triacylglycerols and the matrix coreis coated by one monolayer of phospholipids embeddedwith intrinsic proteins [1] Oil bodies could exist as separateunits and serve as an emulsifying agent in a wide varietyof products which range from imitation milk and yogurtto ice cream [2 3] Numerous studies have described theextraction isolation and characterization of oil bodies fromvarious plant materials [4 5]

The morphological characteristics of oil bodies such assize and shape are species-dependent these characteristicsare affected usually by nutritional and environmental factors[6 7] Oil bodies in different oleaginous plants vary insize from nanoscale to a few 120583m [8 9] For instancesimilar diameters have been observed (145 120583m) in maize andsunflower and the average size of peanut oil bodies is closeto 2120583m [7 10] Moreover the intraspecies differences of oilbodies in different varieties of coffee have shown that C

arabica had a different size distribution [11] In addition anumber of researches have been conducted which mainlyfind some relations between contrasted oil extractabilityand the structural organization of oil bodies (OBs) betweendifferent varieties [12 13]

In general the stability of oil bodies is crucial to the effec-tiveness of its commercial application in foodmanufacturingPrevious studies have investigated the influence that factorssuch as pH ionic strength and thermal processing had on thestability of oil bodies that were extracted from differentoilseeds For instance oil bodies that were extracted fromsoybeans were stable to aggregation in only a narrow rangeof pH values (pH = 2 and pH ge 6) and NaCl concentrations(le25mM) [14] Adams et al [15] reported that the oil bodiesof pumpkin seed proved to be stable to aggregation at pHvalues that were sufficiently far from their isoelectric point(pH 3ndash35) at relatively low salt concentrations (lt50mM)and they were stable at temperatures to 374∘C In the above-mentioned papers 120577-potential has been widely applied as anessential indicator to evaluate the stability of colloid particles[14 16ndash18] If the absolute value of 120577-potential of suspendingparticles was high it meant these particles were excluded byeach other and there was no trend to flocculation [19] To

Hindawi Publishing CorporationJournal of ChemistryVolume 2016 Article ID 5808172 8 pageshttpdxdoiorg10115520165808172

2 Journal of Chemistry

gain more information about the behavior of oil bodies inan aqueous environment muchmore properties of oil bodiesthat originated from other oilseeds should also be conducted

Peanuts are an important oilseed and economic crop inChina The total output of peanut in China is at the leadingposition around theworld in 2015 which reaches 16500 thou-sand metric tons (FAS-USDA) [20] More than 80 of pro-duction inChina takes place in eight provinces Henan Shan-dong Hebei Guangdong Anhui Sichuan Liaoning andGuangxi Moreover Henan is also the largest producersamong these eight provinces [21] There are mainly fourclasses of peanut in Henan yuhua series kainong seriespuhua series and yuanza series Yuhua series grow mostwidely in Henan province [22] Peanut is typically character-ized by approximately 36ndash54 lipids 21ndash36 proteins and alow percentage of carbohydrates and ash [23] To our knowl-edge however the stability of oil bodies from a numberof sources has been carried out until now handful ofliteratures on oil bodies prepared from peanut was sourceable and studied And there is much less research on cellulardistribution in cells and properties of oil bodies fromdifferentpeanut varieties under various environmental conditions

Oil bodies were recovered in the form of cream (oilbodies) using an aqueous extraction method in our workThe characteristic differences of oil bodies that were extractedfrom different peanut varieties were observed with trans-mission electron microscopy and a particle size analyzerbefore and after extraction The charge stability of oil bodiesextracted from five peanut varieties and how they wereaffected by pH and ionic strength were also the main goalsof this study

2 Materials and Methods

21 Materials Peanuts of five varieties (yuhua23 yuhua27yuhua9719 yuhua9830 and yuhua9502 harvested in August2014 in Henan province China) were supplied by HenanAcademy of Agricultural Sciences and stored at 4∘C untilused The composition (g kgminus1 dry matter) of peanuts isshown in Table 1 Glutaraldehyde osmium tetraoxide Spurrrsquosresin uranyl acetate and lead citratewere purchased fromSPISupplies Other chemicals which were of analytical-gradewere purchased from Sinopharm Chemical Reagent Co Ltd(Shanghai China) Water was obtained from a Milliporewater purification system (ge182MΩ Milli-Q Millipore) andit was used in all runs

22 Analysis of Oil Bodies in the Peanut Cell with TransmissionElectron Microscopy Sections of 1-2mm of five seeds eachper variety which were cut in the middle transversally by arazor bladewere fixed in 25 (vv) glutaraldehyde in sodiumphosphate buffer (01M pH72) at 4∘C overnight and washedfor 30min with the same buffer three times Samples werepostfixed in 1 (wv) osmium tetraoxide for 2 h washed30minwith the same buffer three times and then dehydratedin a series of increasing acetone concentrations Dehydratedsamples were infiltrated progressively and embedded inSpurrrsquos resin and cut into ultrathin sections (50ndash70 nm thick)

Table 1 Composition (g100 g dry matter) of five peanut varieties

Peanut varieties Lipid Protein Lipidprotein rateYuhua23 454 plusmn10B 225 plusmn03B 20Yuhua27 439 plusmn08C 220 plusmn05B 20Yuhua9719 413 plusmn08D 265 plusmn06A 16Yuhua9830 487 plusmn09A 211 plusmn04C 23Yuhua9502 483 plusmn10A 225 plusmn04B 21Data were expressed as means plusmn standard deviations The data in the lipidand protein column marked with different capital letters were significantly(119875 lt 001) different

with an ultramicrotome (UC5 Leica Wetzlar Germany)Sections were mounted on copper grids stained with 2uranyl acetate and Reynoldrsquos lead citrate for 10min each andexamined with a transmission electron microscope (H-7650Hitachi Chiyoda-ku Tokyo Japan) that was operated at anaccelerating voltage of 80 kV Images were recorded with a4K CCD camera (832 ORIUS Gatan Pleasanton CA USA)Three biological repeats were performed for each peanutvariety and more than 10 ultrathin sections per block wereexamined [24]

23 Size Measurements of Oil Bodies in the Peanut CellIn order to determine the oil bodies and protein bodiesdiameter 80 to 140measurements of oil body diameter and 15to 20 measurements of protein body diameter were taken oneach image (from 10 images per sample type) obtained fromTEM at the same magnification (5 120583m or 6000x) by NanoMeasurer 12 The determination of mean diameter of theoil bodies and protein bodies was based on the results of 10images Statistical analysis of the data was performed usingthe SPSS 190 software

24 Extraction of Oil Bodies from Peanut Seeds Oil bodieswere isolated using an aqueous extraction method with somemodifications [8 25] In brief the dehulled peanut seeds werepeeled and then were comminuted by liquid nitrogen A 20 gsample of crushed peanuts was transferred to the beaker anddispersed in deionised water at a 1 5 (wtvol) seeds-to-water ratio The mixture was stirred by a Fluko homogenizer(18 000 rpm FM200) for 10 sThemixturewas then incubatedfor 1 h at 45∘C in a constant temperature bath shaker (THZ-82 Huafeng Jintan China) Then the resulting slurry wasfiltered through four layers of gauze cloth The filtrate washandled with a centrifuge (DZ267-32C6 anting ShanghaiChina) at 4000 rpm for 30min The oil bodies appeared asa cream at the top of the centrifuge tube which was collectedin a tube as a creamy pad from the top of the mixture Oilbodies were stored at 4∘C for not more than 24 h

25 Particle Size Analysis of Peanut Oil Bodies after AqueousExtraction Oil bodies were diluted to a concentration ofapproximately 01 wtvol by adding water to the beaker andthen it was leached by ultrasonic baths to ensure homogene-ity The particle diameter distribution was measured using alaser particle size analyzer (Microtrac S3500 America)

Journal of Chemistry 3

26 Preparation of Oil Body Suspensions and Measurementsof Zeta (120577) Potential The influence of pH and ionic strengthon oil body suspensions was achieved by the method [15]with slight modifications Oil body suspensions were madeby suspending 1 g of cream with 9 g of buffer solution 10mMNa2HPO4sdotNaCl (0 10 40 80 and 100mM) at pH30 74 and

90 whichwas then incubated at 37∘C for 20min and stored atthe room temperature (25∘C) for 24 h prior to the analysis of120577-potential

Suspensions obtained from the treatments above werediluted to a concentration of approximately 005wtvolDiluted suspensions were measured directly by a zeta (120577-) potential analyzer (Brookhaven Instruments CorporationAmerica) 120577-potential of the emulsion was measured threetimes with two freshly prepared parallel samples Statisticalanalysis of the data was performed using the SPSS 190software

3 Results and Discussion

31 Size of Oil Body from Five Peanut Varieties in the Cell Inchina Henan ranks as the Chinese largest peanut producerwhich is located in the Yellow River basin There are mainlyfour classes of peanut in Henan yuhua series kainongseries puhua series and yuanza series Meanwhile yuhuaseries grow most widely in Henan province [22] In thiswork the common varieties (yuhua23 yuhua27 yuhua9502yuhua9719 and yuhua9830) in the yuhua series were selectedin order to reflect some difference of oil body propertiesbetween peanut varieties basing the difference of lipid andprotein content The average values of lipid and proteincontent of these varieties are shown in Table 1 The resultsshowed that the protein ranged from 211 g kgminus1 to 265 g kgminus1and the lipid varied from 413 g kgminus1 to 487 g kgminus1 NormallyHenan peanuts are characterized by approximately 440ndash560 g kgminus1 lipid and 220ndash300 g kgminus1 protein [22] Table 1 alsoshows that the five peanut varieties involved high middleand low levels of lipid and protein content All data inthe Table 1 were processed by SPSS the results of monofactor analysis of variance indicated that there existed obviousdifference of lipid and protein content (119875 lt 001) betweenpeanut varieties

The original oil bodies that were distributed throughoutpeanut cells were generally sphere-shaped (Figure 1) Theseentities were abundant and they occupied much more intra-cellular volume than the protein bodies that were surroundedby oil bodies Oil bodies and protein bodies were closelyassociated in the peanut cells This distribution is differentthan in soybean cotyledons [26] As shown in Figure 1 therewas no uniformity in size distribution or organization of oilbodies among the different peanut varieties Moreover themorphological characteristics of oil bodies and protein bod-ies of peanuts showed that the oil body and protein bodywereclosely inside the cells and this appearance might determinethe interaction of oil and protein in extraction Moreover inthis case oil bodies couldmaintain their spherical shape evenif sometimes they appear to be pressed against each other[11] Measurements of oil bodies and protein bodies diameter

where possible revealed an average diameter fromfive peanutvarieties (Table 2) The mean diameter of oil bodies fromyuhua9719 and yuhua9830 is apparently larger than yuhua23yuhua27 and yuhua9502 (119875 lt 001) Yuhua27 had muchlarger protein bodies than the other four peanut varieties(Table 2) Additionally the standard value of deviation of oilbodies of yuhua27 and protein bodies of yuhua 9719 wassmaller than the other varieties (Table 2) so yuhua27 andyuhua 9719 had a more uniform size of oil body and proteinbody respectively Oil body diameter range of all examinedsamples is calculated fromTable 2 yuhua27 shows a narrowerdistribution range of 074ndash283120583m For another thing thewider diameter range of protein body from five peanutvarieties is yuhua27 (252ndash1349 120583m) It was indicated thatthere existed an intraspecific difference in size of oil bodyand protein body [27] These characteristics may partiallycorrelate with the content of oil and protein For exampleoil bodies of strains of maize with high oil content werelarger and more regular compared with a strain with lowoil content although these two strains were characterized bydifferent morphology [28] However there emerged a casethat yuhua9719 with low oil and high protein content alsohad a larger oil body mean diameter So it was possible thatlarger diameter of oil bodies was due to the lower or higherrate of oil and protein content which was not consistent withthe results fromprevious research [11] All these differences indistribution and size characteristics among the five peanutvarieties were greatly attributed to differences in genotypesgiven that the analyzed varieties had the same geographicalorigin and were grown under similar agronomic conditionsThese observations reflected the possibility that there isintraspecies morphological variation among oil bodies assuggested by Crisafulli et al [29]

32 Size Change of Oil Bodies from Five Peanut Varietiesafter Aqueous Extraction To understand the difference andchange in size of oil body further the median diameter ofpeanut oil bodies from different varieties was determinedafter aqueous extraction (Figure 2) Yuhua27 and yuhua9502showed anarrowdistributionwithmedian diameter (D50) of408120583mand 301 120583m respectivelyYuhua9719 and yuhua9830exhibited a similar distribution with about 50 of oil bodiesless than 1386 120583m and 1303 120583m respectively The D50 ofpeanut variety yuhua23 was 789120583m These results showedthat the mean diameter of oil bodies clearly became enlargedafter extraction compared with the initial state in the cell(Table 2) Similar results were obtained where the mediandiameters of oil bodies from yuhua9719 and yuhua9830 wereobviously larger than the other peanut varieties comparedwith the initial diameter in the peanut cell (see Table 2) Thereason may be that the protein in the peanut was releasedmoved to the surface of the oil body and exposed buriedhydrophobic amino acids to the surface of the oil body duringextraction [30] Consequently the initial oil bodies and thecoextracted exogenous proteins (storage proteins) probablyformed a second layer around the oil bodies [5] Thus thediameters of extracted oil bodies were larger than the initialsize in the peanut cell


Table 2 Oil bodies and protein bodies diameter (mean plusmn standard deviation) and minimum (119889min) andmaximum diameter (119889max) (120583m)

Peanut varieties Oil bodies Protein bodiesMean diameter 119889min 119889max Mean diameter 119889min 119889max

Yuhua23 159 plusmn009B 071 300 452 plusmn072B 162 953Yuhua27 163 plusmn017B 074 283 788 plusmn400A 252 1349Yuhua9719 194 plusmn029A 061 396 330 plusmn061B 105 640Yuhua9830 192 plusmn019A 087 504 373 plusmn065B 146 695Yuhua9502 165 plusmn015B 055 316 275 plusmn095B 087 602Values are means plusmn SD with the 119875 value lt 001 from a one-way ANOVA analysis Letters after means indicate significant differences in means

PBCW

OBs

(a)

CW

PB

OBs

(b)

PB

CW

OBs

(c)

OBsCW

PB

(d)

OBs

PB

CW

(e)

Figure 1 The transmission electron microscope (TEM) pictures of five peanut varieties ((a) yuhua23 (b) yuhua27 (c) yuhua9719 (d)yuhua9830 and (e) yuhua9502) Bar represents 5120583m (PB protein body CW cell wall OBs oil bodies)

In addition the degree of difference among the diameterof oil bodieswas different whichwas yuhua9719gt yuhua9830gt yuhua23gt yuhua27 gt yuhua9502 this sequence is almost inaccordance with mean diameter level of peanut oil bodies incell However the degree of increase in diameter was variousbetween peanut varieties These differences may have beendue to the different amounts of acidic amino acid and proteinstructure on the surface of the oil bodies among the differentpeanut varieties [31] For instance yuhua9719 and yuhua9830

showed a much wider diameter distribution than yuhua27and yuhua9502 because yuhua9719 contained much moreprotein and yuhua9830 contained much more oil That ismuch more protein was attached to oil bodies in yuhua9719but many more oil bodies potentially aggregated to form stilllarger units for yuhua9830 in the extractionThedistributionsof protein bodies and oil bodies the contents of proteinand oil and the ratio of protein and oil may combine tohave a joint effect on the diameters of oil bodies in aqueous


05 1 10 40 70

0

3

6

9

12

vol

ume

Volume mean diameter (120583m)

Figure 2 Diameter distribution of oil bodies extracted fromdifferent peanut varieties (◼ yuhua23 e yuhua27 998771 yuhua9719998787 yuhua9830 and permil yuhua9502) Results are expressed as thepercentage of the total volume of all the lipid particles

extraction [3] When exogenous protein reaches the surfaceof oil bodies strong viscoelastic films can be developed thatresist environmental stresses and which provide electrostaticand steric stabilization [32] Thus understanding the chargestability of oil bodies that are extracted from different peanutvarieties may provide important insights into the stability ofpeanut oil bodies and it might also yield guidelines as to thetype of food matrices (eg acidic neutral and alkaline) inwhich oil bodies of suitable peanut varieties could be utilizedsuccessfully

33 Influence of pH on Charge Stability of Oil Bodies Extractedfrom Five Peanut Varieties Zeta (120577) potentials could be usedas indicators of the stability of oil body suspensions [16]Guidelines classifying particles dispersions with 120577-potentialvalues of plusmn(0ndash10)mV plusmn(10ndash20)mV and plusmn(20ndash30)mV andgt plusmn30mV as highly unstable relatively stable moderatelystable and highly stable [33] 120577-potentials of the oil bodysuspensions (in 10mMphosphate buffer) in different salt con-centrations (0ndash100mM) were observed at various pH values(pH30 pH74 and pH90) with the aim of knowing howcharge stability would be affected by a combination of pH andsalt concentration (Figure 3) The results of tests of between-subjects effects of the univariate analyses concerning 120577-potentials of oil bodies extracted from different peanutvarieties at different salt concentrations under various pHare also given by SPSS It indicated that NaCl concentration(119875 lt 0001) and pH (119875 lt 0001) were significantly associatedwith 120577-potential Additionally we modeled the impact of thevariables jointly and detected that interaction of pH andNaClconcentration was also significant (119875 lt 0001)120577-potentials of the oil bodies extracted from five peanut

varieties remained positive at pH30 (Figure 3(a)) On theother hand these values remained negative at pH74 andpH90 (Figures 3(b)-3(c)) The better charge stability of these

five peanut varieties was at pH74 without salt Cao et al [34]proved that the charge property of oil bodies was affected bypH possibly because amino acid residues at the N- and C-terminus of the surface of oil bodies are attributed to pHThe positively charged amino acid residues of the N- and C-terminus are deprotonated by alkaline pH which decreasesthe number of salt bridges between oleosins and phospho-lipids As a result contaminated proteins could not anchorto oil bodies as strongly as before [34] and the coalescenceof oil bodies was more likely to emerge Consequently oilbodies have a net positive charge under acidic conditions anda net negative charge in the neutral or alkaline environmentIn this experiment five peanut varieties had different chargelevels at the same NaCl concentration under pH30 74 and90 which may be due to differences in the amount of acidicamino acid in the protein structure on the surface of the oilbodies [31] For instance two rapeseed genotypes (Amberand Warzanwski) have different stability due to the differentcomposition of H-oleosins and steroleosins phospholipidsand sterols on OBs surface [12]

With the increase in pH 120577-potential of oil bodies changedfrom positive to negative in accordance with the surfacecharge under various salt concentrations In this test theisoelectric point of oil bodies was at 120577-potential of zero (thesefigures not show) Oil body suspensions have maximal desta-bilization at these zero 120577-potentials and this property canbe used as an estimate of the isoelectric point [25] Theisoelectric point of oil bodies from different peanut varietieswas predicted according to 120577-potential of pH30 and pH74under different conditions of ion strength (NaCl concentra-tion of 0 10 40 80 and 100mM) The isoelectric point of oilbodies from yuhua23 yuhua27 yuhua9719 yuhua9830 andyuhua9502 was between pH45 and pH55 at 0ndash10mM NaClconcentrations and our isoelectric points were distinctlydifferent from some published results [4 7 14 35 36] Withthe further increase in NaCl concentration the point of zerocharge of five peanut varieties changed Therefore furtherwork is required to establish the potential role of the pointof zero charge on the stability of oil bodies extracted fromdifferent peanut varieties

34 Influence of Salt Concentration on Charge Stability of OilBodies Extracted from Five Peanut Varieties With increasingNaCl concentration at different pH values 120577-potentials of oilbodies from all five peanut varieties fell significantly (Figures3(a)ndash3(c)) High salt concentration resulted in a distinctlylower stability at pH30 pH74 and pH90 At pH30 120577-potential of oil bodies was over 22mV in the absence of saltwhich indicated that moderate charge stability exists As thesalt concentration increased the positive value declined 120577-potential of yuhua27 and yuhua9719 fell ultimately by 72and 73 respectively but 120577-potential of yuhua9830 andyuhua9502 decreased only slightly However the absolutevalue of 120577-potentials of yuhua9502 and yuhua9719 declineddramatically by 92 and 90 at pH74 in the given range of0ndash100mMNaCl concentrations The top 120577-potential value ofthese peanut varieties appears under the condition of 0mMNaCl at pH74 Particularly 120577-potentials of yuhua27 and


Yuhua23Yuhua27Yuhua9719

Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0

10

20

30

40

50

10 40 80 1000Concentration of NaCl (mM)

(a)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

minus50

minus40

minus30

minus20

minus10

00 10 40 80 100

Concentration of NaCl (mM)

(b)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0 10 40 80 100Concentration of NaCl (mM)

minus50

minus40

minus30

minus20

minus10

0

(c)

Figure 3 120577-potential of peanut oil bodies at different salt concentrations under various pH values ((a) pH30 (b) pH74 and (c) pH90)where error bar represents standard deviation

yuhua9830 were as high as minus40mV At pH90 the absolutevalue was significantly lower for yuhua27 and yuhua9719 at0ndash100mM NaCl concentrations but 120577-potential of yuhua23was reduced only slightly

These results showed that there was a general decreasein the absolute value of 120577-potential with increasing NaClconcentration and that all five peanut varieties were stable(120577-potential gt 20mV) at low salt concentrations (lt10mM)at pH74 and pH90 Meanwhile yuhua27 and yuhua9830exhibited outstanding charge stability (120577-potential gt 35mV)

in neutral microenvironment without salt concentration Inparticular yuhua9830 had nice charge stability in neutraland alkaline microenvironment without salt concentrationThus the adaptability of oil bodies from yuhua9830 to neutraland alkaline condition was better than other four peanutvarieties Similar results were obtained in soybean oil bodiesthat were uncoated by 120581-carrageenan [37] and in oil bodiesfrom a maize germ suspension in the absence of SDS [16]This decrease in 120577-potential absolute value in the range of0ndash100mM NaCl concentrations may be due to electrostatic


screening effects and to decreases in the energy of theelectrostatic interaction brought about by the salt [38 39]The relative insensitivity of 120577-potential of oil bodies fromsome peanut varieties to the addition of NaCl may be dueto the presence of some endogenous salt in the peanut cell[14] Thus low salt concentration can benefit the solubility ofthe surface protein of oil bodies in the aqueous media andenhance the stability of oil bodies although increased saltconcentrations have the opposite effect on the stability for theweaken protein hydration [14]

4 Conclusion

With the aim of understanding the possible difference ofoil bodies from different varieties the diameter and zeta (120577)potential of oil bodies from five peanut varieties (yuhua23yuhua27 yuhua9719 yuhua9830 and yuhua9502) were stud-ied The results showed that oil bodies occupied much moreintracellular volume than the protein bodies that were sur-rounded by oil bodiesThe differences in size and distributionof oil bodies and protein bodies in peanut cells existedamong five peanut varieties In the peanut cell the meandiameters of oil bodies from yuhua9719 and yuhua9830 wereapparently larger than yuhua23 yuhua27 and yuhua9502yuhua27 had much larger protein bodies than the other fourpeanut varieties The median diameter of oil bodies from fivepeanut varieties increased markedly and variously comparedwith the initial oil bodies in a cell after aqueous extractionand the degree of increase is based on the diameter levelof oil bodies in cell The zeta (120577) potential results of oilbodies from five peanut varieties under different conditionsof pH and salt concentration showed that oil bodies werestable at low salt concentrations (lt10mM) at pH74 andpH90 at room temperature Of the five peanut varietiesyuhua27 and yuhua9830 possessed excellent charge stability(120577-potential gt 35mV) in neutral microenvironment withoutsalt concentration In particular the adaptability of oil bodiesfrom yuhua9830 to neutral and alkaline condition was betterthan other four peanut varieties

Disclosure

This article does not contain any studies with human oranimal subjects

Competing Interests

The authors declare that there are no competing interestsregrading this paper

Acknowledgments

This work was supported by National Science Foundation ofChina (no 21376064 and no 21176058)

References

[1] J T C Tzen ldquoIntegral proteins in plant oil bodiesrdquo ISRNBotanyvol 2012 Article ID 173954 16 pages 2012

[2] S Gallier K CGordon andH Singh ldquoChemical and structuralcharacterisation of almond oil bodies and bovine milk fatglobulesrdquo Food Chemistry vol 132 no 4 pp 1996ndash2006 2012

[3] C V Nikiforidis A Matsakidou and V Kiosseoglou ldquoCom-position properties and potential food applications of naturalemulsions and cream materials based on oil bodiesrdquo RSCAdvances vol 4 no 48 pp 25067ndash25078 2014

[4] C V Nikiforidis and V Kiosseoglou ldquoAqueous extraction of oilbodies frommaize germ (Zea mays) and characterization of theresulting natural oil-in-water emulsionrdquo Journal of Agriculturaland Food Chemistry vol 57 no 12 pp 5591ndash5596 2009

[5] C V Nikiforidis V Kiosseoglou and E Scholten ldquoOil bodiesan insight on their microstructuremdashmaize germ vs sunflowerseedrdquo Food Research International vol 52 no 1 pp 136ndash1412013

[6] A H C Huang ldquoOleosins and oil bodies in seeds and otherorgansrdquo Plant Physiology vol 110 no 4 pp 1055ndash1061 1996

[7] J T C Tzen Y-Z Cao P Laurent C Ratnayake and A H CHuang ldquoLipids proteins and structure of seed oil bodies fromdiverse speciesrdquo Plant Physiology vol 101 no 1 pp 267ndash2761993

[8] C V Nikiforidis O A Karkani and V Kiosseoglou ldquoExploita-tion of maize germ for the preparation of a stable oil-body nanoemulsion using a combined aqueous extractionndashultrafiltration methodrdquo Food Hydrocolloids vol 25 no 5 pp1122ndash1127 2011

[9] G I Frandsen J Mundy and J T C Tzen ldquoOil bodies andtheir associated proteins oleosin and caleosinrdquo PhysiologiaPlantarum vol 112 no 3 pp 301ndash307 2001

[10] A H C Huang ldquoOil bodies and oleosins in seedsrdquo AnnualReview of Plant Physiology and Plant Molecular Biology vol 43no 1 pp 177ndash200 1992

[11] P Crisafulli L Navarini F Silizio A Pallavicini and A IllyldquoUltrastructural characterization of oil bodies in different coffeaspeciesrdquo Tropical Plant Biology vol 7 no 1 pp 1ndash12 2014

[12] C Boulard M Bardet T Chardot et al ldquoThe structuralorganization of seed oil bodies could explain the contrasted oilextractability observed in two rapeseed genotypesrdquo Planta vol242 no 1 pp 53ndash68 2015

[13] P Jolivet C Deruyffelaere C Boulard et al ldquoDeciphering thestructural organization of the oil bodies in the Brassica napusseed as a mean to improve the oil extraction yieldrdquo IndustrialCrops and Products vol 44 pp 549ndash557 2013

[14] D Iwanaga D A Gray I D Fisk E A Decker J Weiss and DJ McClements ldquoExtraction and characterization of oil bodiesfrom soy beans a natural source of pre-emulsified soybean oilrdquoJournal of Agricultural and Food Chemistry vol 55 no 21 pp8711ndash8716 2007

[15] G G Adams S Imran S Wang et al ldquoExtraction isolationand characterisation of oil bodies from pumpkin seeds fortherapeutic userdquo Food Chemistry vol 134 no 4 pp 1919ndash19252012

[16] R Sukhotu X Shi Q Hu K Nishinari Y Fang and S GuoldquoAggregation behaviour and stability of maize germ oil bodysuspensionrdquo Food Chemistry vol 164 no 12 pp 1ndash6 2014

[17] N Nantiyakul S Furse I D Fisk G Tucker and D A GrayldquoIsolation and characterization of oil bodies from Oryza sativa


bran and studies of their physical propertiesrdquo Journal of CerealScience vol 57 no 1 pp 141ndash145 2013

[18] X Shi and S Guo ldquoEffect of diluent type on analysis of zetapotential of colloid particles of soymilk proteinrdquo Transactionsof the Chinese Society of Agricultural Engineering vol 32 no 7pp 270ndash275 2016

[19] M Kosmulski ldquoZeta potentials in nonaqueous media how tomeasure and control themrdquo Colloids and Surfaces A Physico-chemical and Engineering Aspects vol 159 no 2-3 pp 277ndash2811999

[20] FAS-USDAOilseeds World Markets and Trade httpappsfasusdagovpsdonlinepsdHomeaspx

[21] W M Zhang Rural Statistical Yearbook in China ChinaStatistics Press Beijing China 2015 (Chinese)

[22] S L YuChinese Peanut Varieties andTheir Genealogy Shanghaiscientific and Technical Publishers Shanghai China 2008(Chinese)

[23] C LHoffpauir ldquoPeanut composition relation to processing andutilizationrdquo Agricultural and Food Chemistry vol 1 no 10 pp668ndash671 1953

[24] J Cao Y Song H Wu L Qin L Hu and R Hao ldquoUltrastruc-tural studies on the natural leaf senescence of Cinnamomumcamphorardquo Scanning vol 35 no 5 pp 336ndash343 2013

[25] G Payne M Lad T Foster A Khosla and D Gray ldquoComposi-tion and properties of the surface of oil bodies recovered fromEchium plantagineumrdquo Colloids and Surfaces B Biointerfacesvol 116 pp 88ndash92 2014

[26] A Rosenthal D L Pyle and K Niranjan ldquoAqueous andenzymatic processes for edible oil extractionrdquo Enzyme andMicrobial Technology vol 19 no 6 pp 402ndash420 1996

[27] A Huang J Tzen K Lee F Bih J Ting and C RatnayakeldquoSeed oil bodies in maize and other speciesrdquo Botanical Bulletinof Academia Sinica vol 34 no 4 pp 289ndash297 1993

[28] J T L Ting K Lee C Ratnayake K A Platt R A Balsamoand A H C Huang ldquoOleosin genes in maize kernels havingdiverse oil contents are constitutively expressed independentof oil contents size and shape of intracellular oil bodies aredetermined by the oleosinsoils ratiordquo Planta vol 199 no 1 pp158ndash165 1996

[29] P Crisafulli F Silizio A Pallavicini and LNavarini ldquoOil bodiesultrastructure in green coffee seeds with different geographicaloriginrdquo in Proceedings of the ASIC 23rd International Conferenceon Coffee Science Bali Indonesia October 2010

[30] P Walstra Physical Chemistry of Foods CRC Press 2002[31] L Wang Q Wang H Liu L Liu and Y Du ldquoDetermining

the contents of protein and amino acids in peanuts using near-infrared reflectance spectroscopyrdquo Journal of the Science of Foodand Agriculture vol 93 no 1 pp 118ndash124 2013

[32] S Tcholakova N D Denkov I B Ivanov and B CampbellldquoCoalescence stability of emulsions containing globular milkproteinsrdquoAdvances in Colloid and Interface Science vol 123-126pp 259ndash293 2006

[33] V R Patel and Y K Agrawal ldquoNanosuspension an approach toenhance solubility of drugsrdquo Journal of Advanced Pharmaceuti-cal Technology amp Research vol 2 no 2 pp 81ndash87 2011

[34] Y Cao L Zhao Y Ying X Kong Y Hua and Y Chen ldquoThecharacterization of soybean oil body integral oleosin isoformsand the effects of alkaline pH on themrdquo Food Chemistry vol177 pp 288ndash294 2015

[35] P C Calder and P Yaqoob ldquoLipid raftsmdashcomposition charac-terization and controversiesrdquoThe Journal of Nutrition vol 137no 3 pp 545ndash547 2007

[36] R L C Chuang J C F Chen J Chu and J T C TzenldquoCharacterization of seed oil bodies and their surface oleosinisoforms from rice embryosrdquo Journal of Biochemistry vol 120no 1 pp 74ndash81 1996

[37] N-NWu X Huang X-Q Yang et al ldquoStabilization of soybeanoil body emulsions using 120580-carrageenan effects of salt thermaltreatment and freeze-thaw cyclingrdquo Food Hydrocolloids vol 28no 1 pp 110ndash120 2012

[38] D J McClements Food Emulsions Principles Practices andTechniques CRC Press Boca Raton Fla USA 2005

[39] G A Martınez-Munoz and P Kane ldquoVacuolar and plasmamembrane proton pumps collaborate to achieve cytosolic pHhomeostasis in yeastrdquo Journal of Biological Chemistry vol 283no 29 pp 20309ndash20319 2008

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


gain more information about the behavior of oil bodies inan aqueous environment muchmore properties of oil bodiesthat originated from other oilseeds should also be conducted

Peanuts are an important oilseed and economic crop inChina The total output of peanut in China is at the leadingposition around theworld in 2015 which reaches 16500 thou-sand metric tons (FAS-USDA) [20] More than 80 of pro-duction inChina takes place in eight provinces Henan Shan-dong Hebei Guangdong Anhui Sichuan Liaoning andGuangxi Moreover Henan is also the largest producersamong these eight provinces [21] There are mainly fourclasses of peanut in Henan yuhua series kainong seriespuhua series and yuanza series Yuhua series grow mostwidely in Henan province [22] Peanut is typically character-ized by approximately 36ndash54 lipids 21ndash36 proteins and alow percentage of carbohydrates and ash [23] To our knowl-edge however the stability of oil bodies from a numberof sources has been carried out until now handful ofliteratures on oil bodies prepared from peanut was sourceable and studied And there is much less research on cellulardistribution in cells and properties of oil bodies fromdifferentpeanut varieties under various environmental conditions

Oil bodies were recovered in the form of cream (oilbodies) using an aqueous extraction method in our workThe characteristic differences of oil bodies that were extractedfrom different peanut varieties were observed with trans-mission electron microscopy and a particle size analyzerbefore and after extraction The charge stability of oil bodiesextracted from five peanut varieties and how they wereaffected by pH and ionic strength were also the main goalsof this study

2 Materials and Methods

21 Materials Peanuts of five varieties (yuhua23 yuhua27yuhua9719 yuhua9830 and yuhua9502 harvested in August2014 in Henan province China) were supplied by HenanAcademy of Agricultural Sciences and stored at 4∘C untilused The composition (g kgminus1 dry matter) of peanuts isshown in Table 1 Glutaraldehyde osmium tetraoxide Spurrrsquosresin uranyl acetate and lead citratewere purchased fromSPISupplies Other chemicals which were of analytical-gradewere purchased from Sinopharm Chemical Reagent Co Ltd(Shanghai China) Water was obtained from a Milliporewater purification system (ge182MΩ Milli-Q Millipore) andit was used in all runs

22 Analysis of Oil Bodies in the Peanut Cell with TransmissionElectron Microscopy Sections of 1-2mm of five seeds eachper variety which were cut in the middle transversally by arazor bladewere fixed in 25 (vv) glutaraldehyde in sodiumphosphate buffer (01M pH72) at 4∘C overnight and washedfor 30min with the same buffer three times Samples werepostfixed in 1 (wv) osmium tetraoxide for 2 h washed30minwith the same buffer three times and then dehydratedin a series of increasing acetone concentrations Dehydratedsamples were infiltrated progressively and embedded inSpurrrsquos resin and cut into ultrathin sections (50ndash70 nm thick)

Table 1 Composition (g100 g dry matter) of five peanut varieties

Peanut varieties Lipid Protein Lipidprotein rateYuhua23 454 plusmn10B 225 plusmn03B 20Yuhua27 439 plusmn08C 220 plusmn05B 20Yuhua9719 413 plusmn08D 265 plusmn06A 16Yuhua9830 487 plusmn09A 211 plusmn04C 23Yuhua9502 483 plusmn10A 225 plusmn04B 21Data were expressed as means plusmn standard deviations The data in the lipidand protein column marked with different capital letters were significantly(119875 lt 001) different

with an ultramicrotome (UC5 Leica Wetzlar Germany)Sections were mounted on copper grids stained with 2uranyl acetate and Reynoldrsquos lead citrate for 10min each andexamined with a transmission electron microscope (H-7650Hitachi Chiyoda-ku Tokyo Japan) that was operated at anaccelerating voltage of 80 kV Images were recorded with a4K CCD camera (832 ORIUS Gatan Pleasanton CA USA)Three biological repeats were performed for each peanutvariety and more than 10 ultrathin sections per block wereexamined [24]

23 Size Measurements of Oil Bodies in the Peanut CellIn order to determine the oil bodies and protein bodiesdiameter 80 to 140measurements of oil body diameter and 15to 20 measurements of protein body diameter were taken oneach image (from 10 images per sample type) obtained fromTEM at the same magnification (5 120583m or 6000x) by NanoMeasurer 12 The determination of mean diameter of theoil bodies and protein bodies was based on the results of 10images Statistical analysis of the data was performed usingthe SPSS 190 software

24 Extraction of Oil Bodies from Peanut Seeds Oil bodieswere isolated using an aqueous extraction method with somemodifications [8 25] In brief the dehulled peanut seeds werepeeled and then were comminuted by liquid nitrogen A 20 gsample of crushed peanuts was transferred to the beaker anddispersed in deionised water at a 1 5 (wtvol) seeds-to-water ratio The mixture was stirred by a Fluko homogenizer(18 000 rpm FM200) for 10 sThemixturewas then incubatedfor 1 h at 45∘C in a constant temperature bath shaker (THZ-82 Huafeng Jintan China) Then the resulting slurry wasfiltered through four layers of gauze cloth The filtrate washandled with a centrifuge (DZ267-32C6 anting ShanghaiChina) at 4000 rpm for 30min The oil bodies appeared asa cream at the top of the centrifuge tube which was collectedin a tube as a creamy pad from the top of the mixture Oilbodies were stored at 4∘C for not more than 24 h

25 Particle Size Analysis of Peanut Oil Bodies after AqueousExtraction Oil bodies were diluted to a concentration ofapproximately 01 wtvol by adding water to the beaker andthen it was leached by ultrasonic baths to ensure homogene-ity The particle diameter distribution was measured using alaser particle size analyzer (Microtrac S3500 America)














PBCW

OBs

(a)

CW

PB

OBs

(b)

PB

CW

OBs

(c)

OBsCW

PB

(d)

OBs

PB

CW

(e)





05 1 10 40 70

0

3

6

9

12

vol

ume











Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0

10

20

30

40

50


(a)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

minus50

minus40

minus30

minus20

minus10

00 10 40 80 100


(b)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)


minus50

minus40

minus30

minus20

minus10

0

(c)







4 Conclusion


Disclosure


Competing Interests


Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of














PBCW

OBs

(a)

CW

PB

OBs

(b)

PB

CW

OBs

(c)

OBsCW

PB

(d)

OBs

PB

CW

(e)





05 1 10 40 70

0

3

6

9

12

vol

ume











Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0

10

20

30

40

50


(a)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

minus50

minus40

minus30

minus20

minus10

00 10 40 80 100


(b)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)


minus50

minus40

minus30

minus20

minus10

0

(c)







4 Conclusion


Disclosure


Competing Interests


Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


05 1 10 40 70

0

3

6

9

12

vol

ume











Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0

10

20

30

40

50


(a)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

minus50

minus40

minus30

minus20

minus10

00 10 40 80 100


(b)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)


minus50

minus40

minus30

minus20

minus10

0

(c)







4 Conclusion


Disclosure


Competing Interests


Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

0

10

20

30

40

50


(a)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)

minus50

minus40

minus30

minus20

minus10

00 10 40 80 100


(b)


Yuhua9830Yuhua9502

120577-po

tent

ial (

mV

)


minus50

minus40

minus30

minus20

minus10

0

(c)







4 Conclusion


Disclosure


Competing Interests


Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



4 Conclusion


Disclosure


Competing Interests


Acknowledgments


References



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article size and charge stability of oil bodies

Documents