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RESEARCH ARTICLE

San Joaquin Valley blueberries evaluated fo r qua lity attributesy Vanessa Bremer, Gayie Crisosto,Richard Molinar, Manuel Jimenez,Stephanie Doliahite and Carlos H. Crisosto

in Californiamated in 2007 at around

acres and is rapidly increasing.on southern highbush culti-

lowchilling-hour require-being grown from Fresno

'Misty'.

e characterized the qualityof soluble

to titratablefirmness and antioxidantofsix southern highbush

at the UCural Center in Parlie

San Joaquin Valley, for three(200S-2007). We also con-

toevaluate the:byconsumers who eat

blueberries. W e found that theSan Joaquinofacceptable

toconsum ers and profitable

ighbush blueberr ies (Vacciniumcorymbosum), native to the north-etal. 2005)

in the world (Strik and YarboroughIn tlie United States, blueberriesincoolerregions; however, the develop-

of new southern cult ivars withof hours below 45F

to the southernan d California (Jimenezl. 2005).

New blueberry cuitivars that require fewer hours of chilling have made it possible togro w this specialty crop pro fitab ly in hot , dry places such as the San Joaquin Valley.Above, a blueberry field day at the UC Kearney Agricultural Center in Parlier.Blueberry production in Californiawas es t imated in 2007 at around 4,500acres (1,821 hectares) and is rapidly in-creasing. Common southern cult ivarsgrown include 'Misty' and 'O'Neal ' ,but other improved southern highbushcultivars are now being grown from

Fresno southward, such as 'Emerald','Jewel' and 'Star ' (Hashim 2004).Southern highbush " low-chil l" cult i-vars are notable for their productivity,fruit quality and adaptation (Draper2007), and require only 150 to 600 chill-hours , making them promising cult i-vars for the San Joaquin Valley's mildwinters (600 to1,200 chill-hours annu-ally). Since 1998, we have conductedlong-term productivity and perfor-mance eva lua t ions of these cult ivars atthe University of California's Kearney

Agricultural Center in Parlier (Jimenezet al. 2005).North American production ofhighbush blueberry has been increas-ing since 1975, due to expansion ofharvested area and yields throughimprovements incult ivars and produc-tion systems. In2005, No rth Americarepresented 69% of the world's acreageof high bus h blueberries, with 74,589acres (30,185 hectares) producing 306.4million p ou nd s (139,000 metric tons).Acreage and production increased 11%and 32%, respectively, from 2003 to2005. The U.S. West, South and Midw estexperienced the highest increases inacreage, hi 2005, 63% of the world's pro-duction of highbush blueberr ies wentto the fresh market. North Americaaccounts for a large part of global high-

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Consumers at a Fresno supermarket participated in taste testsof new southern highbush blueberry cultivars.Blueberry samples were presented in random order forconsumers to taste and rate on a 9-point hedonic scale(dislike extremely to like extremely).

hush blueberry production, represent-ing 67% of the fresh and 94% of theprocessed markets (Brazelton and Strik2007).Blueberry consumption is increasing,which is encou raging increased pro duc-tion. As a result, fresh blueberries are

becom ing a profitable specialty crop,especially in early production areas suchas the San Joaquin Valley (Jimenez etal. 2005). ln gene ral, a cons um er's firstpurc hase is dictated by fruit appe aranc eand firmness (texture). However, subse-quent purchases are dependen t on theconsumer's satisfaction with flavor andquality, which are related to fruit solublesolids (mainly sugars), titratable acidity(organic acids), the ratio of soluble solidsto titratable acidity, flesh firmness andantioxidant activity (Kader 1999).Vaccinium species differ in chemicalcomposition, such as sugars and organicacids. The sugars of the larger high bushblueberry cultivars that are grown inCalifornia are fructose, glucose andtraces of sucrose. Lowbush blueberries

(V. an^ustifolium) which are wild,smaller and grow mostly in Mainelack sucrose. (Kalt and McDonald 1996).The composition of organic acids is adistinguishing characteristic among spe-cies. In highbush cu ltivars, the predomi-nant organic acid is usually citric

(~ 83%), while the percentages of suc-cinic, malic and qu inic acids are 11%,2/ii and 5%, respectively. However, in"rabbiteye" blueberries (V. ashei) thepredominant organic acids are succinicand malic, with percentages of 50% and34%, respectively, while citric acid ac-counts for only about 10% (Ehlenfeldtet al. 1994). These different proportionsof organic acids affect sensory qua l-ity; the combination of citric and malicacids gives a sour taste, while succinicacid gives a bitter taste (Rubico andMcDaniel 1992).

In addition to flavor, consu mersalso value the nu tritional quality offresh fruits and their content of en-ergy, vitamins, minerals, dietary fiberand many bioactive compounds thatare beneficial for human health (Kader1999). Fruits, nuts and vegetables areof great importance for human nutri-tion, supplying vitam ins, mineralsand dietary fiber. For example, theyprovide 91% of vitamin C, 48% of vi-tam in A, 27% of vitam in B6, 17% ofthiam ine and 15% of niacin consum edin the U nited States (Kays 1997). The

daily consum ption of fruits, n uts avegetables has also been related toductions in heart disease, some foof cancer, stroke and other chronicdiseases. Blueberries, like other beries, provide an abund ant supply obioactive compounds with antioxiactivity, such as flavanoids (flavonanthocyanins and others) and phelic acids (Schotsmans et al. 2007). Fexample, a study performed in ratshowed that when they were fed dsupplemented with 2% blueberry etracts, age-related losses of behavi(Alzheimer's disease and other) ansignal transduc tion were delayed even reversed, and radiation-induclosses of spatial learning and memwere reduced (Shukitt-Hale et al.2007). Some studies have shown ththe effects of consuming whole foare more beneficial than consumincompounds isolated from the foodsuch as dietary supplements and ntraccuticals.

Because fruit consumption ismainly related to visual appearancflavor and antioxidant properties, Fresh blueberries are becoming a profitablespecialty crop, especially in early production areassuch as the San Joaquin Valley.

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oxidant capacity and con-

n in California. We characterized

titratable acidity, firm-

Field plots. For the quality evalua-

blueberry cultivars 'Emerald'

675), and three nonp atented 'Reveille', 'O'N eal' andfromby Fall Creek Farm and

2001, the trial plotto kill nut grass (Cyperusand C. esculeiitu^). Becausees require acidic conditions,d, which was incorporated to a depth10 to 12 inches (25.4 ti> 30.5 centime-rs) with flood irrigation, resu lting in a5.{) to 5.5. A completeula r fertilizer (15-15-15) waslied at a rate of 400 pounds(448 kilograms per hectare).The plants were mulched with 4 toches (10.2 to 15 centimeters) of pine

surface of the m ulch, oney was two to three times per

week in the spring and daily duringJune and July. The emitter spacing was18 inches (45.7 centimeters), w ith eachdelivering 0.53 gallon (2 liters) perhour of water acidified with urea sul-furic acid fertilizer to a pfi of 5.0.The plot received an application ofnitrogen in the first season, as well asin subsequent growing seasons. Therate was 80 pound s (36.3 kilograms) ni-trogen per acre at planting, 60 poun ds(27.2 kilograms) the second year, 90pounds (40.8 kilograms) the third yearand 120 pounds (54.4 kilograms) thefourth year. Ann ual pest control waslimited to one application of Pristinefungicide (a combination of the ac-tive ingredients pyraclostrobin andboscalid) in February for botrytis m an-agement, and two or three herbicidetreatments of paraquat (Gramoxone).In year three, the plants received oneinsecticide treatement of spinosad(Success) for thrips management.Twenty-eight plants per cultivarwere planted in a random ized blockdesign u sing seven p lants per block(row) as an experimental unit, repli-cated in four rows. Rows were spaced11 feet (3.4 meters) apa rt, with theplants in the rows spaced 3 feet (0.9meter) apart, with a space of 4 feet(1.2 meters) between plots. Fruit w asharvested at times when it would havebeen comm ercially viable if it hadbeen in a commercial field. Fruit fromeach of the seven plant blocks washarvested and a composite sam ple of80 random berries per each replicationwas used for quality evaluations.Quality mea surem ents. Berries wererandomly selected from each replica-tit)n for quality evaluation at the firstharvest time for each respective season(2005-2007). During the 2007 season,in addition to the initial quality evalu-

After harvest, blueberries were testedfor, /eft, soluble solids concentration(shown, Gayle Crisosto w ith refractometer),center, titratab le acidity (sh own , VanessaBremer wit h automatic titrator) and, right,firmness (shown, fruit texture analyzer), aswell as other qualities.

atit)ns, harvested berries w ere storedat 32"F (0"C) in plastic clam shells, andmeasured for firmness 15 days afterharvest and for antioxidant capacity5, 10 and 15 days after h arvest. Threereplications per cultivar (2005-2007seasons) were measured for each qual-ity parameter. The initial firmness of10 individual berries per replicationwas measured with a Fruit TextureAnalyzer (FTA) (Gss, GS.14, Strand,South Africa) (Slaughter and Rohrbach1985). Each berry was compressed onthe cheek with a 1-inch (2.5 centime-ters) flat tip at a speed of 0.2 inch persecond (5 millimeters) to a depth of0.16 inch (4 millimeters) and the m axi-niLim value of force was expressed inpounds force (lbf) (1 lbf = 4.5 N ewtons),Sixty be rries per replication w erethen wrapped together in two layers ofcheesecloth and squeezed with a handpress to obtain a composite juice sam-ple. The juice was u sed to determinesoluble solids concentration (SSC) witha temperature-compensated handheldrefractometer (model ATC-1, AtagoCo., Tokyo, Japan) and expressed as apercentage. Twenty-one hun dred ths ofan ounce (6 grams) of the sam e juicesample was used to determine titratableacidity (TA) with an automa tic titra-tor (TIM850 auto-titrator. RadiometerAnalytical, Lyon, France) and reportedas a percentage of citric acid. Somesamples that had a high viscosity werecentrifuged with a superspeed centri-

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TABLE 1. Production of six southern highbublueberry cultivars (20 05-20 07)'

fuge (SerVall type SS-1, U.S.A.) at 15,000rpm for 5 min utes , in order to get liquidjuice for soluble solids concen trationand t i t ratabie acidi ty measurements(both methods were compared and nodifferences were observed [data notpublished]). The ratio of soluble solidsconcentration to titratable acidity wascalculated.Antioxidant analysis. Antioxidantcapacity (Trolox Equivalent AntitixidantCapacity [TEAC]) was measured inthe 2005 and 2007 seaso ns. E ighteen-hun dre dth s of an ounce (5 grams) ofberries (not used for quality measure-ments) per replication was used todetermine the level of antioxidiints bythe PPH free-radical method (Brand-W illiams et a l. 1995). Samp les w ereextracted in methano l to assure a goodphenolic representat ion, homogenizedusing a polytron (Ultra-Turrax TP18/101 SI, Junke & Kunket, Staiifen,Germany) and centrifuged (Sorvall

Lab assistant Megan Bishop preparesblueberry samples for antioxid ant analysis.

RC5C, Du Ponf Company, Wilmington,Del.) for 23 min utes. The sup ern atan twas analyzed against the standard,Trolox, a water-soluble vitamin Eanalogue, and reported in micromolesTrolox equivalents per gram of fresh tii:--sue (iimoles TE/g FW).Consumer tests. An in-store con-sume r test was conducted on ' jewel' ,'O'Neal' and 'Star' blueberry cultivarsin 2006, and on the six blueberry cul-tivars studied in 2007, using me thod sdescribed previously (Crisosto andCrisosto 2001). The fruit samples wereheld for 2 day s after harv est at 32F (0C)prior to tasting. One hu ndred consumerswho eat fresh blueberries, representinga diverse com bination of ages, ethnicgroup s and genders , were surveyed in amajor supermarket in Fresno County.Each consumer was presented witha sample of each blueberry cul t ivar inrandom order a t room temperature ,68"F (20^C). A sample consisted ofthree fresh whole blueberries pre-sented in a 1-ounce (30 milliliters)souffl cup labeled with a three-digitcode. At the supermarket , the sampleswere prepared in the produce roomout of sight from the testing area. Foreach sample , the consumer was askedto taste it , and then asked to indicatewhich statement best described howthey felt about the sample on a 9-pointhedonic scale (dislike extremely to likeext remely). Consumers were ins t ructedto sip bot t led water between samplesto cleanse their palates. Consumeracceptance was measured as bothdegree of liking (on a scale of 1 to 9)and percentage acceptance, which wascalculated as the number of consumersliking the sample (score > 5.0) dividedby the total number of consumerswithin that sample (Lawless andHeymann 199S). In a s imi lar manner ,the percentage of consumers disl ik-ing (score < 5.0) and neither liking nordisliking (score = 5.U) the sample wascalculated.

Statistical analysis. Qual i ty val -ues (firmness, SSC, TA, SSC:TA andTEAC) and data on degree of l ikingwere analyzed wi th analys i s of var i -ance (mult i factor ANOV) and LSDm ean s epa ra t i on (P

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TABLE 2. Characterist ics of six southern highb ush bluebe rry cult ivars

f its low titratable acid-e lowest ratio due to itstitratable acidity. The rest of thermed an interm ediate group

d from 17 to 20.3.' and 'O 'Neal' also had the low-(1.2 lbf), while 'Reveille'(1.6 lbf).

(1.5 lbf).Quality attributes were also signifi-

and lowest in 200 6,ty w as highest06 . Soluble-solids-to-titratable-ess w ere signifi-ly higher in 2007 than the othercant interac-l these q uality attribu tes (table 3).The lowest soluble solids concentra-10.8% in 20 06 for 'O'Neal' andwas 15 ,8% for 'Reveille'. During this 3-ycar period,

which has been proposed as a

e seasons except for 'O'Neal' in0.3%, and 'Jewel'20 06 w ith about 1.0%.soluble-solids-to-titratable-

ratios from 11.4 to 20 .6.3-ycar period, 'Jewel' andal' were the softest cu ltivars, and' and 'Reveille' the firmest.Antioxidant capacity was signifi-y different among the cultivars

wide variability of TEAC

EAC within this gro up. Like thenificant interaction between

Cult ivarEmeraldJewelStarReveilleO'NealMisty

Plant statureErectErectErect

Very erectErect

Spreading

Harvest per iod *Early/midseason

EarlyEarlyEarlyEarly

Early/midseason

Fruit sizet50-80

60-10050-70

100-130100-13080-130

Berry gradedLargeLargeLarge

Me d iu mMe d iu mMe d iu m

Hand-harvest ease [Mode rately easyMode rately easy

Very easyModera te

EasyDi f f icu l t

Harvest period sppcifies nitiation of harvest. Early = initia l harvest; early/midseason = 7 days latert Number of berries per 5 oz, (0.18 liter) cup.F Based on average fru it size: extra large. < 64 berries/cup (6 oz.}; large, 64-91 berries/cup (6 o.);I medium, 92-134 berries/cup (6oz.).Source: Jimenez et al. 2005.

TABLE 3. Qua lity attribute s of six southern highbush b lueberry cu lt ivars grow ingin th e San Joaquin Valley, 2005-2007 (values per c ult ivar and season) 1Cult ivar SSC T A t SSCTA Firmness* TEAC2005EmeraldJewelMistyO'NealReveilleStar2006 ^ H iEmeraldJewelMistyO'NealReveilleStar2007EmeraldJewelMisty0-NealReveilleStar

%12.1 cdef Tl11.9 cdef12.2 cde f11.8 def14.3 ab12.9 bcde i i .Sd e f10.9 efn . i e f10.8 f13.3 bdf11.1 ef12.3 cdef12,3 cdef13.7 be11.5 de f15.8 a11.6 de f

% Citnc ad d0.53 ab0.57 ab0.70 ab0.60 ab0.80 a0.77 a0.90 a1.00 a0.57 ab0.77 a0.70 ab0.70 ab0.60 ab0.73 ab0.83 a0.27 b0-70 ab0-67 ab

ratio18.4 b18.1 b15.6 b19.0 b18.1 b16.4 b13.2 b11.4 b20.6 b14.5 b20.0 b17.4 b20.0 b17.2b17.3 b40 ,5 a22.9 ab17,1 b

Ibf1.60 ab1.07 d1.57 ab1.30 bed1.40 bed1.57 ab1.43 bed1.13 cd1.37 bed1.13 cd1.57 ab1.50 abc1.60 ab1.30 bed1.87 a1.27 bed1.90 a1.50 abc

((.imo/ TE /g FW )19.1 ab10.3 d2 1 , 9 a13.6 ed13.8 cd12.1 d N/A

N/AN/AN/AN/AN/A

13,2 Cd11.7d17,4 bc1 1 ,7 d20.7 ab12.7 d

LSD 0,05 1,88 0,4 8 18.07 0,4 1P value 0,001 0,001 < 0,0001 < 0,0001 0-0042 Soluble solids concentration.t Titratable acidity,t Firmness represents the maxirnum value o f force exprMsed in pounds force (Ibf) (1 Ibf = 4.5 Newtons)required to tom pre the fru it 0,16 inches (4 mm) using a fruit texture analyer with a 1-inch {2.S-centimeters)ftt tip at a speed of 0,2 inch/se( (5 mm/sec).5 TEAC (Trolox Equivalent Antioxid ant Capacity).H Same letters within the same column indicate no significant tiifference between means.

TABLE 4. Acceptance of six southe rn highbush blueberry cult ivars by U,in consumer test du ring 2007 season

Cult ivar Degree o f l ik in g ' Acceptance Neither l ike nor disl ike DislikeEmeraldJewelMistyO'NealReveilleStar

1-96 .2 edt6 .7 b6.9 b5.9 d7.4 a6 .6 bc

7 2 . 38 2 . 284.26 7 . 392.180 .2

%11.94-96 .9

12.92 .08 .9

15 .812 .98 .9

19,85 .9

10,9LSD 0,05 0 ,44P value < 0,0001* Degree of liking: 1 = dislike extremely, 2 = dislike very much, i = dislike moderately, 4 = dislike slighliy,

5 = neither like nor dislike, 5 = like slightly, 7 = like moderately, S = iiice wery much, 9 = like ejttremely,t Same letters with in the same column indicate no significant difference between means.

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capacity (data not shown). Storage ofthe six blueberry cul t ivars at 32F (0C)for 15 da ys did not affect either anti-oxidant capaci ty or firmness, except for'O'N eal ' and 'Misty ' , wh ose firmnesswas reduced slightly but not signifi-cant ly (data not shown).Consumer acceptance. During the2006 sea son, our in-store test results in-dicated that consum ers l iked the threetested cu ltivars slightly to moderately,with an acceptance range of 73.3% to80/0. There were no significant dif-ferences indegree of liking betw'een'Jewel' , 'O'N ear and 'Star'. In thesethree cul t ivars the percentage of con-sumers disliking these fruit reachedabout 17% (data no t shown ).Dur ing the 2007 season, there w eresignificant differences indegree of lik-ing between the six cultivars tested(table 4). In this test, degree of likingvaried from liking slightly to moder-ately. 'Reveille' had the highest (7.4) and'O'N eal ' the lowe st (5.9) deg ree of likingwith an acceptance of 92.1% and 67.3%,respectively. Degree of liking of 'Mis ty 'and 'Jewel' was significantly lower than'Reveille', but higher than 'Star ' and'Emerald' . Acceptance was near 80% for' Jewel' , 'Misty' and 'Star' , while only67% for 'O 'Neal ' and72% for 'Emerald ' .The percentage of consumers that dis-liked these cultivars varied from 5.9/to 19.8%; 'Reveille' and 'Misty' had thelowest disl ike percentage and 'O'N eal 'the highest .Degree of liking for 'Jewel' and 'Star'were similar (from slight to moderate)dur ing the two seasons. For 'O'Neal ' ,the degree of liking decreased from likeslightly-modera tely to like slightly. Thisreduction inconsumer acceptance canbe explained by the change of titratahleacidity from 0.6% to 0.8% in previousyears down to 0.3% in2007 that onlyoccurred in 'O'Neal' . This reduction oftitratable acidity for 'O'Neil ' was inde-p en d en t of soluble solids concentration,which remained between 10.8% and11.8% for the 2005 to 2007 seasons.These results indicated that blueber-ries with very low titratablf acidity(0.3%), despite solub le solids conc entra-tions between 10% and12%, are notacceptable to consu me rs. A similar situ-ation has been observed inwhite and

yellow flesh peaches and nectarines withvery low acid ity (less tha n 0.4%) (C. andG. Crisosto, personal comm unication).This reduction in consumer acceptancealso poin ts out that the ratio of solublesolids to titratable acidity is not a goodindicator ior blueberry taste when titrat-able acidity is low. We are not sure of th ereasons for the low titratable acidity in2007 of 'O'Neal' fruit, which appears tobo independent of other cultivars. The2007 season wa s characterized by highchilling accumulation and a hotter thannormal spring, which could have af-fected 'O'Neal' ripening.Choosing a variety

The six southern highbush blue-berry cul t ivars s tudied ( 'Emerald ' ,'Jewel' , 'Star' , 'Reveille' , 'O'Neal' and'Misty ' ) grow ing in the San JoaquinValley had soluble sol ids c oncentrat ionlevels above the10%> proposed for aminim um qual i ty s tandard . Ti t ratab leacidity ranged from 0.6%* to 0.9%,with the exception of 0.3% (2007) for'O'Neal ' . Firmness ranged from 1.2 to1.6 lbf. 'Revei l le ' was the cul t ivar withthe highest soluble sol ids concentra-t ion, fi rmness and degree of l iking.Antioxidant capaci ty ranged from 10

ReferencesBrand-Williams W. Cuvelier M E. Bersei C 1995.Use of a free radical method to evaluate antioxidantactivity. Le bensmittel W issenschaft Technologie28:25-30,Brazelton D. Strik BC. 20 07, Perspective on theU.S, and globa l blueberry industry, J Am Pom Soc61(3)1144-7,Crisosto CH, Criso5to G M, 200 1, Urideritdndingconsumer acceptance of early harvested 'Hayward'kiwif ruit Postharvest Bid Technol 22,20 5-13 ,Draper A, 2007, Blueberry breeding- Improving theunwild blueberry. J Am Pom Soc 61(3 )140-3.Ehlenfeidt MK, Mered ith Fl, Ballington JR, 1994.Unique organic profile of rabbiteye vs, highbushblueberries. HortScience 29(4):321-3,HashimJ 2004 Blueberry production gaining in Cali-fornia, Western Faim Press. h ttp:/Avesternfarmpress,conVmag/{arming_.blueberry_production_gaining.Jimene? M,Carpenter F, Molinar RH, etal. 2005.Blueberry research launches exciting new Californiaspecialty crop. Cal Ag 59(2t:65-9,Kader AA. 1999, Fruit maturity, ripening, and quaiilyrelationship. Acta Hortkulturae (iSHS) 485 :203-8 .

to 22 Mmoles TE/g FW, with 'M istyand 'Reveil le ' the cul t ivars with hiant ioxidant capaci ty for the 2005 an2007 seasttns. Antioxidant capacityfirmness of the cul t ivars s tudied wnot affected bystorage up to 15 dayat 32F (0C). Blueb erries with verylow titratable acidity, despite accepable soluble sol ids c oncentrat ion, hlower consum er acceptance and deof liking, indicating that the solublsolicis-to-titratable-acidity ratio is ngoiid indicator of consumer acceptfor blueberries .For San Joaquin Valley con ditionthese cul t ivars are al l good optionsour fast-growing, early fresh bluebemarket .

y. Bremer is Research Assistant, G. CrisosAssociate Specialist, S. Doilahite is Researtant, and C.H. Crisosto is Postharvest PhysDepartment of Plant Sciences. UC Davis, at the UC Kearney Agricuitural Center; andlinar and M. Jimenez are Farm Advisors, Uoperative Extension, Fresno and Tulare corespectively. Thanks to the UC Smali Farmand Kearney Agricultural Center for their suon the development of this work.

KaltW, McDonald JE 1996, Chemical compositionof lowbush bluebeny cultivars. J Am Soc Hon Sei

Kays SJ, 1997 Positiarvest Physiology of PerishaPlant Producs. Athens, GA: Exon Pr, 532 pLawless HT, Heymann H, 1998, Sensory Evaluatioof Food: Principles and Practices. Food Science Series- NY: Chapman Hall, 827 p,Rubico SM , McDaniel MR 1992. Sensory evaluatioof acids by free-choice profilin g. Chem ical Senses17(3):273-89,Schotsmans W, Molan A, MacKay B. 2007, Con-trolled atmo5phere storage of rabbiteye blueberrieenhances postharvest quality aspects, PostharvestBiol Technol 44:277-85Shukitt-Haie B, Carey AW, Jenkins D, et al, 2007,Beneficial effeas of fruit extracts on neuronal function and behavior in a rodent model ofaccelerateaging, Neurobiol Aging 28(8): 1187-94,Slaughter DC , Rohrbach RR 1985 Developing ablueberry firmness standa rd, Trans Am Soc Agrie E2 8(3): 986-92Strik B, Yarboiough D, 2005, Blueberry productiontrends in North America, 1992 to 2003 and preditions for grovi-lh. HortTechnol 15 :39I- S,

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