R H-NMR 1 ın and others 2002; ´ C. There was strong ◦ 2010 Institute of Food Technologists Further reproduction without permission is prohibited C ´ anovas and others 2005), though vary The presence of membrane-bound compartments or organelles (Ulmer and others 2002; Casadei and others 2002). within plant cells allowsStudies biochemical show reactions that tocell be the segregated. cytoplasm plasma differs membrane from that other is intracellular enclosing membranes, the for and others 2005),pressure compared to processing other isvor novel potentially and technologies. nutrient less High contentlimited detrimental than effect thermal to on processingBoonyaratanakornkit covalent food because bonds and fla- of (San others its temperatures Mart (Oey 2002), and others especiallyresult 2008). at Most in biochemical a moderate reactions volume(Patterson change 2005). and Application are ofresults therefore in high affected microbial pressure by inactivation to and pressure vation may (Barbosa-C food enhance products inacti- greatly in their abilityis to true withstand pressure for (Pattersonduring other 2005). high As food pressure treatment processingpermeabilization, is technologies, considered but to the microbial be mechanisms death undergo a that under result microbial of high membranes cell pressure are still not completely understood C treatments. The texture of was influenced by the ◦ C and above in the thermal treatments. Membrane destabilization effects ◦ . ´ anovas and others 2005). Vol. 75, Nr. 7, 2010 doi: 10.1111/j.1750-3841.2010.01767.x r In this study, we used chemical, biochemical, and histological techniques to obtain information Two different analytical methods were evaluated for their capacity to provide quantitative information on high pressure, ion leakage, onions, pyruvate, texture, thermal processing Journal of Food Science of onions. These methods allowed for the monitoring of changes in the plasma and tonoplast membranes after high 2 T above in high pressure treatments and at 60 agreement between the methods in thein determination the of integrity the of ranges of the high plasma pressure and and temperature tonoplast that membranes. induce Membrane changes rupture could clearly be identified at 300 MPa and could already be visualized following the 200 MPa and 50 state of the membranes and was abruptly modified once membrane integrity was lost. pressure or thermal600 processing. MPa. High Thermal pressure treatments treatments consisted consisted of 30 of min 5 water min bath holding exposure to times 40, at 50, 50, 60, 100, 70, or 200, 90 300, or on cell membrane permeability andstrong agreement between tissue the integrity variousleakage, after methods into high used, routine pressure it quality and is assurance thermalof possible measurements processing. processed to to Because vegetables. implement determine there something the was relatively severity simple, of such preservation as methods ion and the shelf life formed as asolution. result These of results membrane were permeabilization compared followed to by previously enzymatic determined activity methods and that (2) quantified leakage cell of viability and electrolytes into onion cell membrane permeabilitythese and processing integrity treatments after onpermeability high cell pressure and/or compartmentalization and integrity and thermal texture the processing quality. and methodologies To determine to utilized changes study were: the in (1) impact cell measurement of membrane of a biochemical , pyruvate, Practical Application: Keywords: Abstract: In recent years, high pressure processing of biological sys- Novel food processing technologies are currently being stud- Changes Using Different Analytical Methods and Impact on Tissue Texture Maria E. Gonzalez, Gordon E. Anthon, and Diane M. Barrett Onion Cells After High PressureProcessing: and Comparison Thermal of Membrane Integrity inquiries to author Gonzalez (E-mail: [email protected]) E426 MS 20090979 SubmittedDept. 10/2/2009, Food Accepted Science and 4/23/2010. Technology, Univ. of Authors California, are Davis, with CA, U.S.A. Direct Introduction are microbiologically secure (Barbosa-C tems has received the greatest amount of attention (Welti-Chanes that provide convenience, are free from(Rastogi additives and and preservatives others 2007),tain remain microbiologically the safe, color, and texture, re- product flavor, and (De nutrient Belie attributes andStrategies of to others the meet 2000; fresh such Waldronfood demands and include processing others modification techniques of 2003). existing nologies and/or that the allow for adoption production of of higher novel quality tech- products that ied as alternativesto to traditional satisfy thermal consumer pasteurization demands methods for minimally processed products

E: Food Engineering & Physical Properties ml,prvt nlss o ekg,cl iblt Gnae and (Gonzalez viability and 2010a), cell ex- others leakage, for processing, ion thermal analysis, and pyruvate quantification pressure ample, high the after for integrity allow cell that of methods integrity perme- membrane and/or different ability of pressure results deter- high The processing. after in 2006; thermal integrity use and membrane Barrett for cell in proposed and changes also of (Anthon mination is tissue 1961) Weston onion and in Schwimmer formed pyruvate of (Snaar 2002). others resonance and Weerd magnetic der Van nuclear 1992; Angers- and As Van 1999; 1999), and others others and and (Rastogi bach Verkman impedance 1991; electrical exu- (Stanley 2000), volume and indicators soaking and fluorescent microscopy volume-sensitive fluorescence during scattering, lost light 2002), solids (Saltveit dates and conductiv- the leachates of of measurement using ity including: estimated methods, of been number previously a has Plant permeability life. shelf membrane retention, of cell prediction quality for and tools food quantitative provide of integrity may optimization and cellular for improved allow will for Angersbach turn processing 1994; in This (Knorr the 1999). products to others vegetable changes and and structure cell fruit plant of will of quality storage correlation better or a processing, for handling, allow during integrity of membrane indicator an as the used of integrity. be tonoplast thus content in may pyruvate loss processing a in of and result increase a its An as reach tissue place. to take enzyme reaction the the tonoplast for the occur and of rupture the must (Lancaster or membrane vacuole while permeability the in cells, Changes in the 1981). located Collin of initially cytoplasm is alliinase the enzyme in present S-alk(en)yl are 2002). sulphoxides of others and characteristic (Keusgen are onions derivatives processed strong-smelling These of compounds. variety sulfur a volatile into relatively decompose are compounds quickly aroma and primary unstable The juice. onion lachrymatory fresh smell of the characteristic the or cause which (Z)-propanethial-oxide, thiosulphanates factor corresponding into converted 4.4.1.4) rapidly their are (EC which either alliinase acids, by sulphonic unstable catalyzed form is to reaction The pyruvate, ammonia. acid, (alk)enLylsulphenic and into converted rapidly sulphox- cysteine are disrupted, ides are cells intact When 2002). Lancaster ( and sulphoxide en upoie,i atclrtas( trans particular in sulphoxides, teine nutrients. certain of 2008) extraction others and and 2008) (Oey yield others im- to and lead (Verlinde of may bioaccesability it disruption proved as cases, desired be other may In compartmentalization 2004). cellular oc- others may and compounds (Diaz-Maroto aroma cur and flavor unwanted of development ela hmclratossc sa nraei rwigreac- browning in increase as an 2000), as (V others such tions reactions and compartmentalization chemical (Rastogi cell as architecture in well loss tissue the the of in result changes, a As 1990). others (Vazquez-Tello and a compartmentalization cause may cellular structure of membrane modification in targets alterations first and the stresses, of plant one are of of membranes many cell affecting plants, 1999), In Hayashi functions. their and (Kato tempera- pressure low high as and such ture parameters thermodynamic with phase state undergo transitions and fluid fluidity a lose can in conditions, are physiological which under Membranes, 2000). (Stae- or- Newcomb composition other and and helin structure, and function, vacuole) in the membranes ganelle (surrounding tonoplast the example, . . . pyruvate and leakage, ion integrity, Onion nti ril,a nyai ehdta esrsteamount the measures that method enzymatic an article, this In of loss the by imparted disruption, cellular of quantification The natpatmtra foin oti h drescys- odorless the contain onions of material plant Intact amos-Vigy ´ + --ehlLcsen upoie(adeand (Randle sulphoxide )-S-methyl-L-cysteine z 91,oiaino eial uret,and nutrients, desirable of oxidation 1981), azo ´ 1 -M T H-NMR 2 Gnae n tes21b are 2010b) others and (Gonzalez + )-S-1-propenyl-L-cysteine noswr oldi c ae o 0mnatrpoesn and processing after min 10 for 4 experiment. water at the ice held slice. in initiating onion cooled before the were of refrigerator to Onions center in trials the kept preliminary to were in penetration Slices determined heat for time required the be was which min, 30 l aumpcae ne h aecniin stesecond the were as slices conditions treated same heat the and control. pressure under used High vacuum-packaged were control. U.S.A.) all Kans., second City, a Kansas Koch, as raw Pack, and (easy (approximately treatment, MPa) packaged control vacuum 0 were first that a slices onion de- as untreated the used integrity from were cell packaged obtained vacuum different and slices slice without the onion for single equatorial onions bulb untreated a Raw the the terminations. with of then slices equator and cm or removed middle 1 were into onions cut the were of layer or scale ( test were Tukey linear means using overall mixed The compared treat- 9.1). statistically A different (SAS package the onions. statistical of a same effects using analyze ments the to on used was out procedure measure- model carried texture and all leakage, were ion ments analysis, Pyruvate treatment day. per each analyzed (onions) on on subsamples triplicate 2 in with under days, out different day 3 carried UC were same treatments at the processing applied The on were Davis. Davis treatments processing UC Thermal to refrigeration. pressure-treated back the shipped then were and onions treatment to pressure Ill., (Glenview, shipped high Center were for Research U.S.A.) Strategic onions Fellow Foods Whole and Kraft U.S.A.) treatments. the Calif., processing (Oxnard, for Onions Gills used by provided were ter) betvs odtrieteetn owihteprocessing the which to extent the determine To objectives. to h pyruvate. and 2 of sulphoxides of formation S-alk-(en)yl-L-cysteine period the a of for breakdown temperature the controls room allow and at samples stand onion to processed allowed The were test. for the adjusted of volumes purpose reactant the the with using (2003), assayed Barrett of and was procedure of Anthon the Pyruvate action following tissue. subsequent (DNPH) onion 4-dinitrophenylhydrazine the 2, in and enzyme integrity cell alliinase of the loss the of measure etdi ae aha ihr4,5,6,7,o 90 or 70, 60, 50, 40, either at and bath water MPa) a 0 in (approximately heated vacuum-packed individually were eimws1pr rpln lclad2prso water. of parts 2 and glycol propylene part HP transmitting 1 Power pressure was and The Fluid medium U.K.). vessel (Stansted Essex, L level Stansted, 6 System, pressure a Iso-Lab maximum had unit MPa pressure 800 high an The level. pressure the on rxmtl 20 proximately no treatments Onion Methods and Materials yuaeanalysis Pyruvate eauerie oamxmmo prxmtl 35 approximately of tem- maximum the a compression, to During raised perature experiments. all in recorded were umrzdadteipc fmmrn nert ntetexture determined. the is on quality integrity of membrane component of impact the and summarized -i odtm n nta rcsigui eprtr (T a temperature for unit MPa processing 600 initial and and 300, time 200, hold 50, 5-min to exposed were onions packed ihpesr rcsigtreatments. processing pressure High diame- cm 8 (approximately Sabroso cv. onions yellow Spanish ape eepeae n2dfeetwy ome different meet to ways different 2 in prepared were Samples a as used was enzymatically generated pyruvate of amount The material. Raw hra rcsigtreatments. processing Thermal ◦ ni measurement. until C o.7,N.7 2010 7, Nr. 75, Vol. ◦ .Tepesr ul-ptm n temperature and time build-up pressure The C. h ue aeysae n h rtfleshy first the and scales papery outer The r ora fFo Science Food of Journal P no lcs( mthick) cm (1 slices Onion < 0.05). lcdvacuum- sliced ◦ dependant C ◦ Cfor i E427 )ap-

E: Food Engineering & Physical Properties is = o fresh a = H–NMR 1 a Pyruvate-Loss of Pyruvate-Loss tonoplast integrity Pyruvate-Residual alliinase activity after processing a 100/total conductiv- × x) and to the more fre- + ), (Murray and others 1989; b x . k − ax/(b Treatment = b y is the % of total conductivity of the solu- 0.05). .(1–exp y o b < C P = y C) thaw (ambient temperature) procedure to cause b ◦ Raw Vacuum 40C 50C 60C 70C 90C 20 ) was analyzed. 1 − 9 8 7 6 5 4 3 2 1 0 −

10

-intercept of a linear equation fitted to the linear portion of

fwt)

y (umoles*g Pyruvate (Gonzalez 2010b) results. The relationship between membrane -1 The different methods described previously were used to eval- Pyruvate formed in onion tissue as the result of the hydrolysis A puncture test (2 mm diameter flat-tipped cylindrical probe) 2 Saltveit 2002) where tion and x the timethe interval parameter for both a equations. is Inlimiting the the % first asymptote total model, of conductivity reached theto and curve reach parameter that half b represents is asymptote the the (1/2 time time). In the second model, C uate onion cellpreviously membrane obtained cell integrity viability (Gonzalez and 2010a) were and compared to the of S-alk(en)yl cysteine sulphoxides (located in the cytoplasm) by was performed withSystem, a Haslemere, texture England). analyzer Eightobtained (TA.XT2, 1 Stable from cm Micro the diameteronion. The equatorial pieces test was were region performed toonion of 90% scale deformation the of thickness the and original 3rdinitial the slope scale test (gradient speed on from was(Nmm each initial set point to to 1 20% mm/s. maximum The force) complete rupture of cellsductivity (Palta measurements and were obtained others with 1977a,(Accumet a portable 1977b). conductivity AP65, Con- meter Fischer Scientific,were Singapore). fitted The data to the models: integrity and texture quality was evaluated. the the data atleakage long to incubation times, thewere and medium fitted with k (Saltveit a the nonlinear 2002).was procedure rate (SAS The selected 9.1). of by experimental The minimizing electrolyte bestthe data the model effect standard of errors the of treatmentusing the on Tukey test model the ( and model parameters was analyzed weight). Figure 2–Pyruvate formed in onion tissuecator of during integrity thermal of the processing tonoplast (indi- membrane) and(indicator residual alliinase of activity alliinase inactivation due to thermal processing) (fwt conductivity measured at aity). time The interval total conductivity wasfreeze obtained ( after a double cycle of a Integration of cell membrane integrity evaluationand methods texture analysis Results and Discussion Pyruvate analysis cent of total conductivity of the solution (% total conductivity Texture T quently used b a Pyruvate-Loss of Pyruvate-Loss tonoplast integrity Pyruvate-Residual alliinase activity after processing Vol. 75, Nr. 7, 2010 Treatment r b b b b Raw Vacuum 50MPa 200MPa 300MPa 600MPa Journal of Food Science C for 20 min. The reaction was ended by adding 1 mL of

5 4 3 2 1 0 9 8 7 6 fresh weight).

◦

10

fwt) Pyruvate (umoles*g Pyruvate = -1 To measure the impact of the food process (high pressure or The 3rd scale of each onion and equatorial region were used to Onion integrity, ion leakage, and pyruvate . . . 1.5 N NaOH. Absorbanceblank and values standards were were measured preparedpyruvate by at and adding water 515 0 volumes to nm. were 50 adjusted A uL appropriately. of 5 mM thermal) on cellresult integrity, of the the amount processing treatmentof of was alliinase determined pyruvate before by formed tissue inactivation onion as homogenization. samples Control a were and homogenizedthe processed with ratio 1 of M 1procedure TCA : was and 2 followed water : as in the 1. described sample The volume previously for homogenate mentioned, thepyruvate was reaction but content centrifuged was and doubled and the due the NaOH to volumes the of were lower water adjusted, and respectively.pyruvate aliquot The initially of present amount was 1.5 of measured N additional in endogenous amount the of raw control pyruvate and formedcell the was membrane used damage as result an of indicator processing. of E428 Figure 1–Pyruvate formed in onion(indicator tissue during of high integrity pressure of processing activity the (indicator of tonoplast alliinase inactivation due membrane) to high and pressure(fwt processing). residual alliinase Ion leakage treatment inactivated alliinase,maining residual in activity thecompletely of onion homogenizing alliinase tissue tissuepyruvate after re- and formed. processing measuring The was theapproximately samples 1 measured amount were g by prepared of of onion byallowed tissue for homogenizing with alliinase water (1 towhich : react 1), 2 with 15 parts min the were homogenate cysteine 1 was sulphoxides, M centrifuged after for trichloracetic 5force acid min (Centrifuge at (TCA) 5415D, 16.1 Eppendorf, were relativereaction Hamburg, added. centrifuge Germany). was The The started byclarified mixing homogenate, 1.5 in N aonion NaOH homogenate, culture to and neutralize tube 800 the 1501 uL acid of uL mL in distilled volume. of the Then, water the added, to 1 to reach mL the a samples of and final 0.025% theyat were DNPH 37 placed in in a 1 water N bath, heated HCL was obtain 1 cm diametersion onion onion disks disks with were a1 rinsed cork min twice borer. each in Afterferred time, deionized exci- surface water to for blotted petri-dishes, about withavoid then moisture a loss covered (Saltveit paper with 2002) towel3 and damp and h. kept in Samples tissue trans- the were paperbathed refrigerator equilibrated in for to to 20 room mL of temperatureM a for previously mannitol). 1 determined Conductivity h isotonic solution measurements and ferent (0.2 time were periods, obtained 0 at min,The 15 dif- ion min, 30 leakage min, of 1 excised h, onion 2 disks h, 3 was h, calculated and as 4 the h. per-

E: Food Engineering & Physical Properties ert ol eueu npoessta ontla oenzyme to in- lead membrane not do of that indicator processes an in treated inactivation. useful as pressure be pyruvate high would in of tegrity (1994) use characteris- others The organoleptic and inactivation onions. in Butz alliinase changes by of reported the tics consequence with agreement a in present as pyruvate was samples of amount processed reduced of in The inactivation occurred. substantial as- also rupture, alliinase in membrane pressure itself and for by temperature required the value levels at limited because of rupture, high tonoplast is either sessing of processing result a thermal as or indicate formed pressure tissue results in These content pyruvate 2). the these that (Figure with treatments observed temperature also was higher inactivation alliinase and treatments naypoi uv Fgr n ) h equation The 4). followed and time 3 and (Figure bathed) curve the were asymptotic disks an in onion the concentration relation- which electrolyte in The solution (the tissue. conductivity the from between leakage ship ion in others increases and significant (Palta system transport active the influx the to 1977a). decreased to damage a damage or to to membrane, due due plasma leakage efflux the ion increased of net an semipermeability Increased whereas either transport. diffusion, from active passive result to be may due to be considered must be outside influx a may concentration from low efflux is a the to leakage it, cell, the the Since appear- inside translucent. the concentration more high make tissue that plant plant changes into of undesirable leakage ance to ion leads and apoplasts rupture cell Membrane Vasquez-Tello 1990). 1989; others others and and perme- (Murray and membranes intactness the cell of of leak- measurement ability electrolyte a as with used solution, being into long ions age of leakage the in increase iiyi no ic fcnrl n ihpesr rae onions. treated pressure high and conduc- controls total of of discs percent onion a in as tivity leakage ion in increase 3–Cumulative Figure leakage Ion 90 and 70, 60, the of result a as occurred level brane after activity treatment. alliinase pressure residual MPa the 600 by the formed lower pyruvate significantly also the of higher was by amount alliinase indicated At as MPa), pressure, 1). 600 high (Figure and by inactivated 300 higher example, or (for MPa levels pressure 300 high following at occurred treatments level pressure membrane tonoplast processing the that at the indicated changes indicator by content pyruvate caused as in increases integrity used Significant membrane treatments. was tonoplast 2002) of Lancaster loss and of and (Lancaster Randle alliinase 1981; enzyme vacuole-located Collin the of action the . . . pyruvate and leakage, ion integrity, Onion ohhg rsueadtemlteteto nosrsle in resulted onions of treatment thermal and pressure high Both an is alterations membrane accompanying feature common A ntetemlytetdoin,cagsa h ools mem- tonoplast the at changes onions, treated thermally the In

Raw % Total Conductivity 100 20 40 60 80 0 0101020250 200 150 100 50 0 Vacuum 50MPa Time (min) 200MPa 300MPa y = ◦ Cthermal ax/(b 600MPa + x) eeautdi hsatceadi tes o xml,pyruvate example, for others, 2 methods in and different article the this by in in determined evaluated changes we as the of integrity 1986; comparison membrane a (Mohsenin follow- cell illustrates treatments disks 5 Figure thermal onion 2002). or the Bourne pressure of high test either puncture ing a in curve deformation oa odciiyvle fte20Maad50 and MPa 200 the of limiting lower values mem- significantly conductivity in the total changes in observed subtle resulting as more permeability, leakage plasma brane indicated Ion and treatments barriers. tonoplast cell milder the as from acted case longer which no membrane in membranes of achieved, loss complete was A mannitol. integrity M 0.2 in period cubation n h aftmsotie o h otos ihpesr,and pressure, high controls, the onions. for treated obtained thermally times conductivity half total the of percent and limiting the of 1–Comparison Table analysis integrity membrane cell and Texture 70, 60, at treatments thermal and 90 MPa and 600 applied, and pressure temperature 300 High of or reached. treatments conductivity pressure total treat- limiting% of the the processing level higher different indicates the the the 1 higher for Table The model behavior. ments. fitted leakage the of ion parameters the described best iiyi no ic fcnrl n hral rae onions. treated thermally and conduc- controls total of of discs percent onion a in as tivity leakage ion in increase 4–Cumulative Figure eeosre ewe h ifrn ihpesr rthermal or this by pressure described parameter. differences high information additional statistical different no indicating no the limiting treatments, vary, the between to reach observed appeared to were required conductivity values total time % half While 1). (Table auswt omnlte ontdfe infiaty( significantly differ not do letter common a with Values Thermal (min) time Half (%) conductivity total Limiting pressure High Treatment aum9 90 108 70 108 27 60 11 50 11 40 Vacuum MPa 600 MPa 300 MPa 200 MPa 50 Vacuum a 8 9 Raw Raw % Total Conductivity force/ a of slope initial the from determined was stiffness Tissue ◦ ◦ ◦ ◦ ◦ 100 114 110 104 C C C C14C11 20 40 60 80 0 Raw ◦ ece 0%o oa odciiywti h in- h 4 the within conductivity total of 100% reached C 0101020250 200 150 100 50 0 o.7,N.7 2010 7, Nr. 75, Vol. Vacuum 40C Time (min) b d b c c c a a a bc cd a a r 50C ora fFo Science Food of Journal P 60C < 0.05). 70C ◦ treatments C 55 53 49 29 26 21 19 23 21 16 16 16 19 a a a a a a a a a a a a a 90C E429

E: Food Engineering & Physical Properties kage

G H ) Ion leakage measured as % total ∗ fresh weight. Treatment Treatment Treatment Treatment Treatment = m 40C 50C 60C 70C 90C m 40C 50C 60C 70C 90C m 40C 50C 60C 70C 90C m 40C 50C 60C 70C 90C m 40C 50C 60C 70C 90C uu uu uu uu uu c c c c c a a a a a wV wV wV wV wV a a a a a R R R R R 0 0 0 0 8 8 7 6 5 4 3 2 1 0

8 60 40 20 60 40 20 8

1,4 1,2 1,0 0, 0,6 0,4 0,2 0,0

1,6 1,4 1,2 1,0 0, 0,6 0,4 0,2 0,0

100 2 120 120 100 T ) ) s ( Initial Slope (N.mm Slope Initial Relative % Total Conductivity Total % Stained Area Stained

g . s (umole Pyruvate fwt) -1 -1 a a a a a C D E I J B A F A ) Dash line indicates membrane rupture; fwt 600 MP 600 MP 600 MP 600 MP 600 MP ∗∗ a a a a a 00 MP 00 MP 00 MP 00 MP 00 MP a3 a3 a3 a3 a3 200 MP 200 MP 200 MP 200 MP 200 MP (E,J) for high pressure (left) and thermally processed (right) onion samples. ( a a a a a 2 Treatment Treatment Treatment Treatment Vol. 75, Nr. 7, 2010 Treatment r m 50 MP m 50 MP m 50 MP m50 MP m50 H-NMR T m 50 MP 1 uu uu uu uu uu c c c c c a a a a a wV wV wV wV wV a a a a a R R R R R 0 0 0 0 8 8 6 5 4 3 2 1 0 7

8 60 40 20 40 20 8 60

0,4 0,2 0,0 1,4 1,2 1,0 0, 0,6 Journal of Food Science 1,2 1,0 0, 0,6 0,4 0,2 0,0 1,6 1,4

120 100 2 120 100 T ) s ( -1) Initial Slope (N.mm Slope Initial % Total Conductivity Total % Pyruvate (umole Pyruvate fwt) g . s -1 Onion integrity, ion leakage, and pyruvate . . . conductivity; cell viability measured as relative stained area. ( Figure 5–Relationship between tissue stiffness (A,F) and cell membrane integrity as determined by various methods: pyruvate content (B,G); ion lea E430 (C,H); cell viability (D,I); and

E: Food Engineering & Physical Properties emndb o ekg,cl iblt,adprvt otn in content pyruvate de- and viability, as cell treatments integrity ( leakage, MPa tissue membrane ion 600 of by and loss 300 termined complete the the after with stiffness coincided tissue in change eerhwsfne yteCne o dacdPoesn and Processing Advanced for Center (CAPPS). the Packaging by This from processing. funded Tay pressure was high Abdullatif research with and assistance their Lau, for particular Foods Ming in Kraft Turek, thank Evan to colleagues like would our We and Commission. (OAS) States Fulbright American the of Organization the from scholarships minimally of characteristics. quality “fresh-like” and maintain texture monitoring to the vegetables, life processed of shelf pro- optimization of of and improvement result prediction a for as allow occur will that comparison cessing methods. changes valid processing structure more cell thermal of a traditional Knowledge for to allow technologies novel that changes of integrity, quantify to tissue ability plant the and in methods these the using emphasize that of studies treatments validity The integrity. temperature membrane or in changes pressure in high result of range deter- the for employed mining methods the was between There found processing. permeability agreement thermal strong membrane and pressure cell high after on integrity information and obtain to used were n onie ihtegets hne nprvt otn,ion T content, and pyruvate viability, in cell changes greatest leakage, the with coincided and P ramn yteinlaae(iue5) elvaiiy(Fig- viability cell 200 5C), and the (Figure coincided 5D), leakage after ure MPa ion detected the 200 integrity by at membrane treatment in MPa stiffness to loss in compared initial 5A) change the (Figure with This stiffness control. tissue raw of loss the treatment small MPa a 200 the in onions, resulted processed pressure high the In 5F). Acknowledgments Conclusions pressures 50 at above place temperatures taking and changes MPa significant 200 most above the with ness and 2010a) or viability, (Gonzalez cell area 2010b). conductivity), stained (Gonzalez total relative of of (% % leakage ion content, . . . pyruvate and leakage, ion integrity, Onion h hral rcse nosocre ewe 0ad60 and 50 between occurred in onions stiffness processed in thermally decrease significant the most the Similarly, 2010b). zalez r oiso eerhta a il nih nopoesn opti- attributes. processing texture into and insight structure cell yield maintain can to 2002) that mization others research and mi- of Casadei for topics 2002; are suggested others and/or as and transitions proteins (Ulmer phase bound croorganisms lipid membrane as of processing, denaturation rupture during and cells 2005). permeabilization plant others membrane in and increased underlying (Ananta of the causes death is The cell processes for food responsible various cellular of mechanism to result damage a the as that membranes found have which microorganisms, in fruits of texture the 1991). of others and component (Shackel a vegetables as and the turgor emphasizing cell 2007), cells of others onion and importance the Araya within 1994; pressure others turgor and is of (Greve This loss dramatically. the declined of stiffness consequence tissue a the membrane lost, once was processing, onion integrity after that indicate results These h uhr cnweg h nnilspoti em of terms in support financial the acknowledge authors The histological, and biochemical, chemical, approaches, Several ohtemladhg rsuetetet eue isestiff- tissue reduced treatments pressure high and thermal Both hs nig noinclscrepn ihpeiu studies previous with correspond cells onion in findings These 1 -M T H-NMR 1 -M T H-NMR 2 a o esrdaoe20Mai Gon- in MPa 200 above measured not was 2 Fgr E ehd.Tenoticeable The methods. 5E) (Figure 2 eemntos(iue5 o5J). to 5G (Figure determinations ◦ C(Figure5Aand 1 -M T H-NMR ◦ C, 2 ozlzM,BretD,MCrh J egltF,GreaE asrA,VnA H. As Van AM, Matser E, Gerkema FJ, Vergeldt MJ, McCarthy on DM, integrity Barrett cell ME, of Gonzalez Influence 2010a. DM. Barrett DC, Slaughter JA, Jernstedt ME, Gonzalez izMrt C aooE,Csr ,VnsMG ee-oloM.20.Cagspro- red Changes in 2004. loss MS. Perez-Coello turgor MAG, for Vinas model L, kinetic Castro A ES, Palomo 2000. MC, J. Diaz-Maroto Baerdemaeker De W, Herppich N, Belie De aae A aa ,NvnE ed ,Mce M 02 oeo ebaefluidity membrane of Role 2002. BM. Mackey E, Needs E, Niven G, Manas chemical onions: MA, of processing Casadei pressure Diego, Ultra-high San 1994. S. ed. Wolf 2nd B, Tauscher measurement. W, Koller and P, concept Butz viscocity: and texture Food 2002. M. intermolecular Bourne and intra- on effects Pressure 2002. DS. Clark CB, Park BB, Boonyaratanakornkit na ,VnA .19.Poigwtrcmatet n ebaepreblt npatcells plant with in permeability associated membrane and changes compartments turgor water Probing Cell 1992. H. 1991. As Van H. J, Snaar Ahmadi JM, Labavitch C, measure Greve a as KA, onion Shackel in acid pyruvic of development Enzymatic 1961. N.C. WJ. Weston Cary, S, Inc., Schwimmer Insti. SAS 2003. 9.1. SAS le M eehl ,Fhe ,Gnl G itrR oe F 02 fet of Effects 2002. RF. Vogel R, Winter MG, Ganzle S, Fahsel H, Heberhold tissues. HM, food in Ulmer losses quality associated and In: deterioration membrane organelles. Biological 1991. membranous D. Stanley and structure Membrane 2000. EH. Newcomb LA, Staehelin Barbosa-C pectin of 2007. activation AJ. Mawson C, temperature Stewart N, Smale the S, Buggenhout Van of B, Verlinden M, Hendrickx Characterization X, Araya 2006. DM. Barrett with GE, acid pyruvic Anthon of determination the for processed method and Modified intact 2003. spray-dried of DM. model of Barrett Electrophysiological GE, stability 1999. Anthon storage D. and Knorr injuries V, Heinz Cellular A, 2005. Angersbach D. Knorr M, Volkert E, Ananta References atetM.20.Tert finlaaefo hligsniietsu osntimmediately not does tissue chilling-sensitive from Mart San leakage ion of Op- rate The 2007. 2002. D. ME. Saltveit Knorr K, Niranjan VM, pressure Balasubramaniam hydrostatic KSMS, high Raghavarao of NK, effect Rastogi Synergistic 2000. D. Knorr A, Angerbasch dehydra- osmotic NK, during Rastogi transfer mass Accelerated 1999. quality. D. flavour Knorr to MN, relation Eshtiaghi in NK, Alliums Rastogi in compounds 98:1400–9. Sulphur of Microbiol 2002. significance Appl JE. Physiol and J Lancaster bulbs foods. Plant WM, pressure-treated onion Randle of cells. of Microbiology bulb 2005. tolerance MF. Freezing onion Patterson 1977b. in EJ. injury Stadelmann J, Freezing Levitt 1977a. J, EJ. Palta Stadelmann processing J, pressure Levitt high J, Does 2008. Palta M. Hendrickx A, Loey rates Van by I, tissues Plancken plant Der in Van damage I, frost Oey of Quantification 1989. D. 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