A study of some of the quality attributes of fresh mango and pineapple fruits

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1 Interntionl Scholrs Journls Africn Journl of Agronomy ISSN Vol. 7 (1), pp , Jnury, 219. Avilble online t Interntionl Scholrs Journls Author(s) retin the copyright of this rticle. Full Length Reserch A study of some of the qulity ttributes of fresh mngo nd pinepple fruits Yon Jfo 1, Jmes Nylndu 2 nd Ngu Bwnmdogo 2 1 Mikocheni Agriculturl Reserch Institute, Coc Col Rod 22, P.O. Box 6226 Dr es Slm, Tnzni. 2 Deprtment of Crop Sciences, Crl-Sprengel-Weg 1, 3775 Göttingen, Germny. Accepted July 3, 217 Horticulture in Tnzni hs become very importnt sector becuse the demnd for orgniclly produced tropicl fruits hs drmticlly incresed worldwide. In this study, orgniclly nd conventionlly grown mngo nd pinepple from different origins were nlyzed for nutritionl vribles. Chrcteriztion of fruit derivtives ws chieved using severl vribles, nmely fruits size nd colour, o brix (mesurement for the sugr concentrtion of liquids), titrtble cidity, ph, orgnic cids, free sugrs, nd minerls. Fruit smples nlyzed were: fresh orgnic mngoes locl cultivrs Dodo, Bolibo, Viringe, cultivr Tommy Atkins nd conventionlly produced cultivrs Kent, orgnic nd conventionl pinepple cultivrs Smooth cyenne. The cultivrs nd their type of cultivtions hve shown n influence on the levels of titrtble cidity, orgnic cids, sugrs nd minerl contents like clcium, potssium, mgnesium nd mngnese. Titrtble cidity ws higher in orgnic thn conventionl mngo cultivrs. Fructose nd glucose contents were 22 nd 28% higher in conventionl thn in orgniclly produced mngo fruits, respectively. Conventionl pinepple fruits hve shown higher fructose nd glucose content by 18 nd 1% s compred with orgnic pinepple fruits. Mlic nd citric cids levels were 3 nd 16% higher in conventionl thn orgniclly grown mngo cultivrs. Mngnese, clcium nd mgnesium contents were 33, 18 nd 12% in orgnic thn conventionlly grown pinepple fruit. Orgnic mngo cultivrs were shown to hve higher contents of phosphorus nd potssium by 17 nd 6%. Key words: Mngo, pinepple, orgnic cultivtion, nutritionl vribles. INTRODUCTION The qulity of fruit vries to lrge extent due to differences in terms of their tste, flvour, colour, rom nd size. Normlly, on purchsing fruits, consumers consider externl ppernce such s freedom from *Corresponding uthor. E-mil: jon_jfo@gmil.com externl dmge, weight, colour nd consistency. Ruben et l. (25) stted tht these qulity vribles re considered in crop mngement nd post-hrvest technologies. Mngo (Mngifer indic L.) nd Pinepple (Anns cosmus) re mong the most importnt populr nd best known tropicl fruits. Acceptble colour nd flvour with high contents of nutrients re importnt fetures in selecting mngo nd pinepple fruit cultivrs for processing. Forney et l. (2) found tht chemicl

2 Jfo et l. 412 composition could be influenced by geogrphicl loction, horticulture prctice, seson nd cultivr. Minerls ply mjor role in humn nutrition nd they re importnt for the mintennce of humn helth (Frossrd et l., 2). For exmple, iron is mjor component of the blood component hemoglobin nd involved in the electron trnsfer system of enzymes. A deficiency of iron my led to ftigue, hedche nd sore tongue in ddition to nemi. Clcium is importnt in bone formtion nd zinc is essentil for protein nd nucleic cid synthesis, crbohydrte metbolism, successful pregnncy, delivery nd norml physiologicl development of the infnt. Mgnesium is involved in most phosphte trnsfer rections, the structurl stbility of nucleic cids nd the intestinl bsorption of nutrients. In most developing countries, minerl deficiency, especilly tht of iron, is still public helth issue probbly due to the over-dependence on plnt food sources (Frossrd et l., 2). During the pek hrvesting seson, fresh fruit fces problems in sustining for lengthy period. Rough hndling of fruit my result in dmge of plnt cellulr structure, which plys protective role for the texture of the fruit. This my led to moisture loss nd ccelertes enzyme ctivities tht cuse browning (Tylor nd Olivs, 27). As result, there is n incresed susceptibility to microbil spoilge, discolourtion nd respirtion, nd finlly fruit loses its qulity. It is thus importnt to be wre of the nutritionl qulity of fruits during their shelf life periods nd the influences of griculturl prctice, geogrphicl loction nd type of cultivrs on qulity vribles. The min objective of the studies ws to evlute some of the qulity ttributes of fresh mngo nd pinepple fruit by evluting the following vribles: weight, colour, totl soluble solids, sugr, minerls, titrtble cidity nd orgnic cids. The hypothesis being tested ws tht griculturl prctice, geogrphicl loction nd type of cultivrs could significntly influence vrition in qulity. MATERIALS AND METHODS The study covered orgniclly nd conventionl grown fruit cultivrs of mngo nd pinepple. Orgniclly grown mngo (Mngifer indig L. cv. Dodo, Bolibo, Viringe) nd pinepple (Anns comosus L. cv. Sooth cyenne) from Tnzni were obtined from locl mrkets in Dr es Slm, Tnzni, nd trnsported by irplne to Germny. Fruit obtined from shops in Göttingen, Germny, were orgnic mngo cv. Tommy Atkins from Burkin Fso, conventionl mngo cv. Kent from the Ivory Cost, Mli, Peru nd Cost Ric, orgnic pinepple cv. Smooth cyenne from Ugnd nd conventionl pinepple cv. Smooth cyenne from Ghn nd Hondurs. All smples were obtined between Jnury nd Mrch in 26, 27 nd 28 nd nlysed in the Lbortory, Section of Qulity Plnt Products, Deprtment of Crop Science t the University of Goettingen, Germny. Five individul smples t similr stge of ripeness were obtined. After removing the nonedible prts, the smples were cut into smll pieces nd frozen. The smples were freeze-dried prior to determintion of minerl content, sugr, orgnic cids nd dry mtter content. Fresh fruit juices were used for the determintion of ph, pulp colour, titrtble cidity, totl soluble solids nd totl sensory evlution. The fruits were stored t Temperture of 13 C, Humidity of 95% nd the moisture content of fruits ws on the verge (88%). Pulp colour mesurement Objective colour mesurements were mde using Minolt Chrom Meter CIE 1976 (model CR-2, Minolt Corp., Rmsey, NJ) clibrted with white plte. CIE refers to the Commission Interntionle de l'eclirge (Interntionl Commission on Illumintion) (McGuire, 1992). Colour ws expressed s CIELAB (L**b*) colour spce, where L* defines the lightness nd * nd b* define the red-greenness nd blue-yellowness, respectively. The more representtive colour vribles re included in the results. In ll cses, five pieces per replicte were used. Sensory evlution The sensory test helps to understnd the ttributes of product from consumer's point of view, which is criticl to its cceptnce. The sensory qulity of orgnic fruit juices, mngo cultivr Dodo nd pinepple cultivr Smooth cyenne from Tnzni were evluted (overll qulity, colour, texture nd rom) by 11 untrined nd rndomly chosen pnelists. For overll qulity nd colour, the scle ws 1-9 (hedonic scle) s described by Meilgrd et l. (2). Pnel test procedures were performed t room temperture. A pnel of eleven judges scored the tste of juice. Like extremely = 9, Like very much = 8, Like modertely = 7, Like slightly = 6, Neither like nor dislike = 5, Dislike slightly = 4, Dislike modertely = 3, Dislike very much = 2, Dislike extremely = 1. Determintion of titrtble cidity, ph, nd totl soluble solids Juice smples were obtined by squeezing hlf of the fruit slices from ech replicte with hnd juicer. Totl

3 413 Afr. J. Agron. soluble solids content ( o Brix) of the juice ws mesured with n Abbe Refrctometer, model 145 (Americn Opticl, Bufflo, NY), nd expressed s percentge. To mesure the ph nd titrtble cidity (TA), 3-5 ml juice smple per replicte ws diluted with 2 ml of distilled wter nd titrted with.1 N NOH to ph 8.1. TA ws clculted s percent of nhydrous citric cid s the predominnt cid (AOAC, 1998). Determintion of sugrs Crbohydrte nlysis frctions were extrcted s described by Keutgen (2). 1 mg of dried fruits smples with 1 ml of distilled wter were heted for 6 min in wter bth t 6 C nd centrifuged for 2 min t 1, rpm. Glucose, fructose, nd sucrose were determined from the membrne filtrted superntnt (dimeter.45 µm). These crbohydrtes were determined by injection of 2 µl smples volume into n HPCL system using LiChrospher 1 NH2 (5 µm) 4 4 mm pre-column (No , Merck KGA, Drmstdt, Germny) in combintion with LiChrospher 1 NH2 4 x 25 mm seprtion column (No , Merck KGA, Drmstdt, Germny). The column temperture of 2 C ws controlled by the column thermostt Jetstrem 2 (Knuer, Berlin, Germny). An cetonitrile: pure wter solution (8:2 v/v) ws used s mobile phse (flow rte 1. ml min -1 ). A Knuer differentil refrctometer 198. (Knuer, Berlin; Germny) ws used to detect crbohydrtes contents in the fruit smples nd their concentrtions were clculted ccording to the method of Keutgen (2). The sum of glucose, fructose, nd sucrose ws considered s mesure of soluble crbohydrtes. The results were expressed in % of dry mtter. Determintion of orgnic cids For mesurement, the smples were prepred s described for crbohydrtes. This determintion ws modified fter Neumnn ccording to the method of Mentsti et l. (1985), Keefer nd Schuster (1986) nd Szmigielsk et l. (1997). The protonted orgnic cids (ph of eluent = 2.2) ws seprted by hydrophobic interctions with the polr sttionry phse of the reversed phse column. The HPLC consists of n Inline Degser (Wter, Germny), Mxi Str, K 1 HPLC pump (Knuer, Germny), LKB utosmpler 2157 (Phrmci, Germny), UV/VIS - Photodiodenrry Detector 996 (Wters, Germny), Multi - Eluents support system Wter 6E Powerline nd Millennium dt cquisition system (Wters, Germny). Orgnic cids were seprted with 25 4 mm Lichrospher-1 5 µ RP-18 column with gurd column (Merck, Germny) t flow rte of.5 ml/min nd temperture of 2 C. 18 mmkh2po4 wter solution (ph 2.2) s isocrtic solution ws used s eluent. The concentrtion of the orgnic cids ws detected t 21 nm (smple volume 2 µl). The results were expressed in % of dry mtter. Minerl content Mcro nd micronutrients determintion in the smples were crried out ccording to the procedure used by Abu- Smr et l. (1975) nd Prdede (24). 4 mg mterils were weighed in specil plstic vessel resistnt to het nd cid (MPV 1, Germny) with 4 ml nitric cid (65%) ws dded. After being covered, the smples were tightly closed in specil metl holder nd heted up t 175 C for 12 h in n oven (Memmert GmbH - Germny). The resulting solutions were nlyzed for mgnesium (Mg) nd iron (Fe) using AAS (tomic bsorption spectroscopy) from Perkin-Elmer (USA), potssium (K) nd clcium (C) using FES (Flme Emission Spectrometer, Elex 6361) from Eppendorf - Germny nd phosphorus (P) using Spectrophotometer (Hewlett Pckrd 8453, Germny) following the P-yellow method on P (Wilhelm et l., 1983). Sttisticl nlysis The generted dt were entered into spred sheet nd imported into SigmStt progrm version 2, where vrious sttisticl tests were performed using ANOVA. A lest significnt different (LSD) test, multiple comprison test, ws performed in n ttempt to discern if significnt differences existed between the smple mens. RESULTS AND DISCUSSION Size nd colour mesurement A number of vribles relted to fruit qulity were evluted in order to chrcterize the smples. The men weight of the mngoes rnged from pproximtely 5 to 7 g, being clssified from medium to lrge. These sizes meet the mrket requirements for fresh mngo consumption (Crvlho et l., 24). Pinepple weight rnged between 1.4 to 1.8 kg. The fruit circumference in length nd width re shown in Tble 1. In the fruits nd vegetbles, wter represents the highest percentge of totl weight. The mximum mount vries mong fruits of the sme kind due to their structurl differences (Hnfi

4 Jfo et l. 414 Tble 1. Fruit weight, length nd width circumference of mngo nd pinepple fruits. Fruit Fruit weight (g) Length circ. (cm) Width circ. (cm) Origin Production Mngo cultivrs Dodo 578.±73.2bc 3.3±4.66c 25.9±6.77b Tnzni O Bolibo 686.3± ± ±1.97 Tnzni O Viringe 329.3±23.2e 27.±.76d 25.8±.75b Tnzni O Tommy Atkins 56.9±19.8bcd 32.2±1.44bc 29.8±1.48b Burkin Fso O Kent 449.4±23.3d 31.5±.84c 25.8±6.88b Cost Ric C Kent 478.7±46.3cd 31.2±1.82c 29.6±.96b Ivory Cost C Kent 581.1±15.8b 35.4±1.39b 29.6±1.19b Mli C Kent 591.2±88.7b 32.9±1.24bc 3.7±1.6 Peru C Pinepple cultivr Smooth cyenne 172.5± ±1.8b 38.9±1.9 Tnzni O Smooth cyenne 1119.±34.5b 4.±3.46b 38.6±3.75 Ugnd O Smooth cyenne 21.8± ± ±1.15 Cost Ric C Smooth cyenne 194.4± ± ±1.34 Ghn C Smooth cyenne ±98.5b 39.4±.8b 35.5±1.56 Hondurs C Vlues within columns with different letters re significntly different (p.5). Abbrevitions: O=orgnic nd C=conventionl. The determintion of the coordintes L*, *, b* chrcterizes pulp colour. At this scle, L* mesures luminosity tht vries from zero (blck) to 1 (pure white); *nd b* vlues represent the levels of tonlity nd sturtion, with + (indicting red), - (indicting green), + b (indicting yellow) nd - b (indicting blue). Positive vlues of * nd b* s observed re ttributed to the crotenoids present in the pulp. et l., 29). The effect of plnttion mngement could influence the structurl differentition. A reduction in fruit weight, cn cuse fruit shrivelling nd dvnce senescence. In most cses, this is dependent on the reltive humidity surrounding the fruit nd lso could be ssocited with slight reduction in flesh firmness (Nock, 212). Normlly, the weight loss could be due to the rtes of respirtion nd trnspirtion of wter, which could be ttributed to biologicl chnges tking plce during storge. The colour of fruit pulp is shown in Tble 2. Slight differences were found for L, nd b prmeters. L vlues in mngoes rnged between nd 88.99, Dodo cultivrs from Tnzni hd the lowest L vlue s compred with other mngo cultivrs. Pinepples re lower in b vlues indicting less yellow colour. The findings indicted higher vlues of yellowness (b vlues) observed in the mngoes, which could be ssocited with n increse in crotenoids due to the ripening process. Mendes-Pinto (29) reported tht the production of crotenoids increses during the ripening of mngo fruits. Sensory evlution The sensory evlution of orgnic fruits juice of mngo cultivr Dodo nd pinepple cultivr Smooth cyenne collected from Tnzni ws done to ssess the cceptbility to consumers. Mngo cultivr Dodo is very populr for juice mking due to its short shelf life period. Pinepple cultivr Smooth cyenne, during pek periods, tends to mture in bulk. Due to its high perishbility, post-hrvest technology plys mjor role for its humn nutrition suitbility. The qulity ssessment nd durtion of post-hrvest life of fruit re importnt for the mngement of fresh products during the distribution chin, especilly from distribution points to mrkets. The results of the sensory evlution of mngo nd pinepple juices re shown in Tble 3. Differences in the cceptbility of the overll qulity of the fruit juices were observed during the sensory evlution. Mngo juice ws mostly preferred s compred with pinepple juice due to the tste. The tste of pinepple juice scored less, becuse pinepple juice tstes bitter when compred with mngo juices. The importnt ttributes for sensory evlution re level of sugr, slt, titrtble cid nd bitter compounds such s lkloids. These contribute significntly to tste. The sensory chrcteristics of fruit hve been correlted to the levels of sugrs nd orgnic cids nd their rtios (Colric et l., 25). The qulity ttributes for mngo nd pinepple fruits re shown in Tble 4. Pinepple ws shown to hve 3% higher citric cid content when compred with mngo, which contributed to the bitter tste of pinepple juices.

5 415 Afr. J. Agron. Tble 2. Pulp colour in mngo nd pinepple fruits. Fruit L A B Origin Production Mngo cultivrs Dodo 43.16±2.38c -3.39± ±27.82b Tnzni O Bolibo 73.27±5.42b -4.6±7.35b 48.36±13.27b Tnzni O Viringe 81.9±2.97b -6.66±4.43b 69.45±11.3 Tnzni O Tommy Atkins 8.29±1.86b -5.79±2.85b 61.19±3.1 Burkin Fso O Kent 88.99± ±5.55b 39.6±28.2b Cost Ric C Kent 8.89±.98b -9.8±3.16b 72.79±24.15 Ivory Cost C Kent 81.98±1.23b -8.84±2.35b 66.97±4.8 Mli C Kent 77.9±3.52b -5.52±4.45b 73.57±5.4 Peru C Pinepple cultivr Smooth cyenne 55.66±1.28c -3.5± ±.97c Tnzni O Smooth cyenne 8.26± ±.35bc 48.47±3.5b Ugnd O Smooth cyenne 79.85± ± ±3.45 Cost Ric C Smooth cyenne 78.23± ±.42bc 46.4±2.87b Ghn C Smooth cyenne 73.17±5.16b -2.39±6.29b 29.52±35.25 Hondurs C Vlues within columns of the sme fruits with different letters re significntly different (p.5). Tble 3. Sensory nlysis of mngo nd pinepple juices from Tnzni. Prmeter Mngo juice Pinepple juice Appernce 6.88± ±2.96 Arom 6.25± ±2.72 Tste 5.88±1.56b 3.37±2.56b Density 5.25±2.18b 5.±1.85b Overll 5.88± ±2.69 Vlues within columns of the sme fruit juice with different letters re significntly different (p.5). Tble 4. Qulity ttributes of mngo nd pinepple fruits from Tnzni. Attributes Units Mngo cultivr. Dodo Pinepple cultivr. Smooth cyenne TSS o Brix Fructose mg 1g -1 Glucose mg 1g -1 Sucrose mg 1g -1 Tste Score Titrtble Acidity (%) ph Mlic Acid mg 1g -1 Citric Acid mg 1g -1 Sugr/Acid rtio FW FW FW FW FW Mlundo et l. (21) showed tht in sensory nd chemicl evlutions of fruits, the individul sugrs nd orgnic cids, s well s their rtio, could be crucil in determining the tste. The orgnic cids ply n

6 Jfo et l. 416 Tble 5. Titrtble cidity (TA) in citric cid, ph, mlic cid (MA) in nd citric cid (CA) in mngo nd pinepple fruits. Fruit TA(%) ph MA CA (mg 1g -1 FW) Origin Production Mngo cultivrs Dodo 1.89±1.1bc 3.63±.11bc.74±.43c.32±.12b Tnzni O Bolibo 2.31±.24b 3.62±.3bc.84±.8bc.26±.6bc Tnzni O Viringe 2.37± ±.8bc 1.24±.11b.21±.9c Tnzni O Tommy Atkins 1.25±.6bc 3.63±.1bc 1.61±.9.2±.3c Burkin Fso O Kent 1.3±.15c 3.7±.9b.84±.16bc.24±.3bc Cost Ric C Kent 1.43±.11bc 3.5±.2c 1.34±.22b.31±.12bc Ivory Cost C Kent 1.12±.8c 3.63±.12bc 1.67±.14bc.38±.16 Mli C Kent 1.31±.4bc 3.85± ±.48b.36±.11b Peru C Pinepple cultivr Smooth cyenne 1.52±.53b 3.79±.21b.12±.3b.43±.15 Tnzni O Smooth cyenne 2.23±.9 3.3±.2c.8±.1c.38±.1b Ugnd O Smooth cyenne 1.69±.27b 3.62±.11b.18±.8.32±.8c Cost Ric C Smooth cyenne 2.35± ±.6b.11±.1bc.38±.3b Ghn C Smooth cyenne 1.±.2b 4.3±.6.13±.4b.29±.9bc Hondurs C Vlues within columns of the sme fruits with different letters re significntly different (p.5). importnt role in fruit tste through the sugr/cid rtio. Although pinepple showed 3% higher sugr to cid rtio s compred with mngo, pnelists scored less for pinepple when compred with mngo. Sugr provides sweetness nd the orgnic cids sourness. The min orgnic cids present in fruits re citric nd mlic cids (Krdeniz, 24). In fruit, the content of sugr nd orgnic cid ccounts for sweetness nd cidity (Mlundo et l.,21). Kim et l. (215) found the tste of fruit ws influenced by the blnce between orgnic cids nd soluble sugrs, minly citric cid nd mlic cids, fructose nd glucose, respectively. Titrtble cidity, ph, nd orgnic cids The rtio H+/ cidity could be used s n index of mturity. The cidity my be useful s reference to the stge of mturity or s objective informtion relted to flvour. Therefore, fruit with lower cidity would hve sweeter flvour. Chnges in ph re ssocited with the cid content, which chnges during the development, nd consequently low ph ( ) vlues indicte high cid concentrtions. Titrtble cidity is directly relted to the concentrtion of orgnic cids present in the fruits. Orgnic cids, minly citric cid nd mlic cid, together with sugr contribution of fructose nd glucose led to their mutul ction, which derives the sweetness nd sourness of fruits (Degree et l., 212). Fruit qulity is one of the severl criteri to be considered in mking some industril products, for exmple, orgnic cids contents in fruits, fruit chemicl compounds, types of sugr contents, pigment nd mny others. These vribles hve plyed mjor role in improving the qulity of the products (Degree et l., 212). The high concentrtion of cid in ripe fruit my not only influence pltbility nd flvour of the derived products, but it my lso ffect the suitbility for specific uses (Sh et l., 211). It is commonly known tht different types of fruit contin different mounts of orgnic cids due to the fct tht edible fruits re used s food cidultes in mnufcturing beverges nd drinking juices. Some orgnic cids in ripe fruits my influence the sensory properties of the derived products, even though they my be considered s minor components (Sh et l., 211). When they re present in combintion with sugrs, they could possibly be n importnt influence on the sensory qulity of both rw nd processed fruits (Turhn nd Seniz, 29). Orgnic cids, such s citric, mlic, oxlic, scorbic nd trtric cids. could influence the flvour t the ripe stge (Shui nd Leong, 22). The orgnic cids s n importnt fruit component for mking juices nd beverges nd their rtios could determine the percentge of juice content (Mlundo et l, 21). In Tble 5, the mngo cultivrs show significnt vrition (p.5) in their titrtble cidity percentge. There were significnt vritions in their titrtble cidity mong the mngo cultivr Kent grown under

7 Citric cid in mg 1g- 1 FW Mlic cid in mg 1g-1 FW 417 Afr. J. Agron p > p <.5.2 b.6.4 p <.5 b.6.4 p <.5 b.2.2 Orgnic Conventionl Orgnic Conventionl n=12 n=12 n=16 n=16 Mngo Pinepple Figure 1. Orgnic cids (mg 1g -1 FW) in conventionl nd orgnic in mngo (n=12) nd pinepple fruits (n=16). Vlues with different letters re significntly different (p.5). conventionl production system in different loctions, which shows n effect of loction on titrtble cidity levels mong the fruits. Mngo cultivr Bolibo nd Viringe ws shown higher titrtble cidity thn other cultivrs nd vlue 54% higher in orgnic thn conventionl fruit. The ph vlues rnged between 3.5 nd 3.85 whereby the mngo cultivr Kent showed higher ph vlue of 3.85 s compred with other mngo cultivrs. Mngo cultivr Kent is normlly hrvested while green nd unripe, which leds to higher citric cid levels thn cultivrs hrvested lter. The ph level ws 1.9% higher in conventionl s compred with orgnic, indicting the sensitivity of ph level in mngo. Mlic cid levels vried significntly (p.5) within the mngo cultivrs nd it ws found to be higher in Kent nd Tommy Atkins. Mlic cid levels were 19.7% higher in mngo cultivrs under conventionl thn orgnic. Citric cid levels were significntly different (p.5) with cultivr Kent nd higher in some loctions thn others. Citric cid levels were 13.9% higher in mngo cultivrs produced in conventionl thn orgnic. The pinepple cultivr Smooth cyenne showed significnt vrition between conventionl nd orgnic production systems. Titrtble cidity ws 6.3% higher in conventionl thn in orgnic. Titrtble cidity is expressed s percentge of citric cid level (Figure 1). Pinepples grown in different loction showed significnt vritions in their titrtble. Likewise the ph vlues vried significntly within the pinepple cultivrs in conventionl nd orgnic being 1.6% higher in conventionl. The level of citric nd mlic cid in pinepple cultivrs vried significntly between the two productions systems. The results showed tht in orgnic production, citric cid ws 15.8% higher thn in conventionl systems, while

8 Jfo et l. 418 Tble 6. Totl soluble solids, fructose, glucose nd sucrose in mngo nd pinepple fruits. Fruit TSS ( o Brix) Fructose Glucose Sucrose (mg 1g -1 FW) Origin Production Mngo cultivrs Dodo 14.2±1.1b 2.26±.36d 1.35±.58de 5.±2.29c Tnzni O Bolibo 1.4±1.5c 2.37±.57d.94±.38e 7.29±2.b Tnzni O Viringe 15.4± ±.49d 1.9±.46e 6.52±.13bc Tnzni O Tommy Atkins 15.9± ±.36b 2.9±.19b 6.86±.56bc Burkin Fso O Kent 12.5±1.1bc 2.87±.28cd 1.42±.16cde 6.54±1.91bc Cost Ric C Kent 15.9± ± ± ±1.6bc Ivory Cost C Kent 11.8±2.1c 3.32±.22bc 1.88±.18bc 7.92±.59 Mli C Kent 15.3± ±.87bc 1.85±.17bcd 5.23±.98bc Peru C Pinepple cultivr Smooth cyenne 15.1±2.1b 2.19±.53b 2.12±.78b 7.14±.54 Tnzni O Smooth cyenne 13.±.7b 2.49±.45b 1.65±.33bc 6.72±2.12b Ugnd O Smooth cyenne 12.8±.7b 1.68±.3b 1.17±.74c 3.4±1.21c Cost Ric C Smooth cyenne 12.6±1.4b 3.76± ±.45b 5.35±.36b Ghn C Smooth cyenne 16.± ±.31b 2.82± ±.35b Hondurs C mlic cid ws 3% higher in conventionl thn orgnic production system. Lu et l. (214) found tht mlic cid rnged from 3 to 161 mg/1 g FW nd citric cids rnged from 114 to 578 mg/1 g FW in pinepple fruits. The lower mlic cid levels in pinepple fruits found in the present study s compred with other literture might be due to the different methods of nlysis or storge. Vrition in time between hrvesting nd lbortory nlysis could ffect the qulity. Totl soluble solids nd sugr content Totl soluble solids content (TSS), sucrose, glucose nd fructose re importnt qulity ttributes, s well s the determintion of fruit mturity. They lso influence the sweet flvour of the product. In mngo, ccording to the vriety nd mturity, this vrible rnges between 9.1 nd 18.27%. The blnce between orgnic cids nd soluble sugrs hs n effect on the tste of fruits. In study by Mlundo et l. (21), it ws found during ripening tht the level of cidity decreses nd the totl soluble sugr concentrtion increses due to conversion of strch into sugrs. The sugr content of fruits hs usully been ssessed in terms of soluble solids content, or non-reducing nd reducing sugrs. Reducing sugrs hve been found to increse, or remin constnt, during ripening. Glucose, fructose nd sucrose hve been reported to be in similr concentrtions in ripe mngoes, nd sucrose hs been shown to be predominnt throughout ripening. In Tble 6, totl soluble solids vlues were found to vry significntly (p.5) in mngo cultivrs under conventionl nd orgnic production system in different loctions nd this is in line with the studies of Leonrdi et l. (2), Goemez et l. (21) nd Morru et l.(24) who found tht the totl soluble solid content is cultivr dependent. In severl studies by Andrews et l. (21) nd Regnold et l. (21), it ws found tht soluble solids nd totl sugrs content were higher in orgnic pples s compred with conventionl. Totl soluble solids (Gil et l., 26) in mngo rnged between 13.7 nd 14.4%. These vlues corresponded with this study's findings only for dodo wheres the cultivrs Tommy ktins nd Kent hd totl soluble solid vlues bove 15.%. In the pinepple cultivr Smooth Cyenne, the vlues vried significntly in orgnic nd conventionl production system in different loction. Gil et l. ( 26) found tht the totl soluble solid in pinepple rnged between 11.1 nd 13%; in this study, the pinepple cultivr Smooth Cyenne ws shown to hve totl soluble solid vlue of 15. nd 16. in some loctions. The levels of reducing nd non-reducing sugrs vried significntly (p.5) mong the mngo cultivrs in different loctions nd, between conventionl nd orgnic production systems. Fructose nd glucose levels were 22 to 28% higher in conventionl thn in orgnic produced mngo cultivrs. It hs been shown tht the growing system nd cultivr could influence the totl nd reducing sugr contents of tomto (Ünlü et l., 211). Mngo cultivrs Tommy Aktins hve shown higher levels of

9 419 Afr. J. Agron. glucose, fructose nd sucrose. Environmentl condition my influence the development of mngo nd s result hs effect on its qulity (Sleh et l., 29). In pinepple, reduced nd non-reducing sugrs were significntly different mong the fruits. Fructose nd glucose levels were higher in conventionl thn orgnic produced pinepple fruits by 2%, while sucrose levels were lmost orgnic nd in conventionl produced pinepple fruits. Anz et l. (26) reported tht since reduced sugrs were not vriety dependent, they were loction dependent. In study conducted by Regnold et l. (21), they found tht effects of interction of fctors such s frming prctices, mount of soil nutrients, plnt vrieties, nd time of hrvest my ffect the nutritionl qulity of products nd could lso complicte the comprison of food from orgnic nd conventionl systems. Although orgnic frming prctices in comprison with conventionl frming prcticed were shown to improve soil qulity (Figure 2). Minerl content in fruits Through the ctivity of soil microorgnism nd plnts, humn beings re ble to obtin essentil minerls nutrients (Lundegårdh, 25). It is known tht vitmins, minerls, wter, nd fibres re mong the mjor constituents for blnced diet (Brt et l., 26). There re direct nd indirect effects of minerls uptke on humn helth. The effects of minerls re directly observed on humn nutrition s consequence of consuming fruit nd vegetbles. In mny foods vitmins, minerls, nd fibre re dded during processing to enhnce the nutritionl qulity of food, which hs helped to decrese mlnutrition (Lrson- Duyff nd Robert, 22). A diet rich in potssium contributes to the lowering of blood pressure due to the blunting effects of slt (sodium), while higher blood pressure hs been ssocited with indequte intke of potssium (McCrronnd Reusser, 21). Clcium is n essentil element for the formtion of bone nd tooth structures, nd, for this reson, clcium requirements re higher during dolescence. Cohen nd Roe (2) found tht clcium is importnt to reduce the risk of osteoporosis, condition in which decresed bone mss wekens the bone. In plnts, clcium is primrily ssocited with the pectic mterils nd it seems to hve mjor influence on the rheologicl properties of the cell wll, n importnt fctor on the texture nd storge life of fruit nd vegetbles. Clcium helps to mintin membrne integrity nd cell structure, nd in metbolic regultion, it cts s secondry messenger (Hepler, 25; Boyer, 29). Mgnesium is importnt for the synthesis of proteins, relese of energy stored in the muscle nd for the regultion of the body temperture. It plys role in hert function nd in the formtion of bone, nd the ctivtion of over 1 enzymes (Lukski, 24). Phosphorus is primry bone-forming minerl. According to DiMggio et l. (2) inorgnic phosphte is n essentil compound for severl physiologicl processes such s skeletl minerliztion nd multiple cellulr functions, including glycolysis, gluconeogenesis, DNA synthesis, RNA synthesis, cellulr protein phosphoryltion, phospholipid synthesis nd intrcellulr regultory roles. Mngnese is importnt for bone development, nd is involved in metbolism of mino cid, lipid, nd crbohydrte. Mngnese is lso found in severl enzymes such s mitochondril superoxide dismutse, glutmine synthetse, rginse, nd involved in ctivtion of severl hydrolses, trnsferses nd crboxylses enzymes. Arredondo nd Núñez (25) stted tht iron (Fe) is needed in severl essentil proteins including the hemecontining proteins, electron trnsport chin nd microsoml electron trnsport proteins, nd iron-sulphur proteins. Iron is lso involved in number of enzymes, such s ribonucleotide reductse, prolylhydroxylse phenyllnine hydroxylse, tyrosine hydroxylse nd conitse. Minerls could not be directly detected through visul inspection or consumption; hence they re referred to s credence ttributes. Normlly, in qulity control progrm, no incentive is given to mesure minerls, unless there re specific nutritionl clims. In judging qulity, consumers bse their perceptions on two kinds of qulity ttributes: purchse ttributes which involve size, colour, firmness to the touch, rom nd bsence of defects; nd consumption ttributes such s flvour nd mouth feel (Shewfelt, 2). Altieri nd Nicholls (212) found tht minerl content could lso ffect most of these qulity chrcteristics, nd the cceptbility of both fruit nd vegetble is lso influenced by severl fctors. In fruits, minerl levels could be influenced by severl fctors such s the vriety of the produce item, time of hrvest, ripeness, climte, nturl soil nutrient sttus s well s the ppliction of fertilizers, nd possibly storge nd mrketing conditions. Phosphorus content vried significntly mong the mngo cultivrs nd this my indicte the effect of cultivr on phosphorus content of the fruits (Tble 7). The phosphorus content rnged between 5.9 nd 8.9 mg 1g -1 FW, which is close to the findings indicted by Wojciech et l. (29), where the men phosphorus content in mngo ws 11 mg 1g -1 FW. Phosphorus content ws found to be higher in orgnic thn conventionl produced mngo, which my be influenced by loction. In the comprison done by Worthington

10 Sucrose in mg 1g -1 FW Glucose in mg 1g -1 FW Fructose in mg 1g -1 FW Jfo et l p <.5 5 p >.5 4 b p < b 2 p > p > b p <.5 Conventionl Orgnic Conventionl Orgnic Mngo Pinepple Figure 2. Sugr contents (mg 1g -1 FW) in conventionl nd orgnic in mngo (n=12) nd pinepple fruits (n=16). Vlues with different letters re significntly different (p.5). (21), phosphorus content ws found to be higher (1.8%) in orgnic thn conventionl crops. Phosphorus content in pinepple did not vry significntly (Tble 7) nd rnged between 6.5 nd 8.5 mg 1g -1 FW, nd tht is close to the vlue of 8. mg 1g - 1 FW indicted by Wojciech et l. (29). Phosphorus content ws not significntly higher in orgnic thn in conventionlly produced mngo nd pinepple fruits.

11 421 Afr. J. Agron. Tble 7. Mcro nd micro minerl content in mngo nd pinepple fruits. Fruit P C K Mg Fe Mn mg 1g -1 FW Origin Production Mngo cultivrs Dodo 8.9± ± ± ± ±.5c.24±.11b Tnzni O Bolibo 8.4± ± ± ±1.1bc.118±.1c.21±.13b Tnzni O Viringe 7.9±1.1b 11.9± ± ± ±.4bc.2±.7b Tnzni O Tommy Atkins 8.1± ± ± ±.3bc.175±.1.35±.17b Burkin Fso O Kent 7.5±1.1b 12.3± ±8.8b 15.6±2.3b.133±.3bc.24±.5b Cost Ric C Kent 7.3±.5b 13.9± ± ± ±.2b.38±.8 Ivory Cost C Kent 5.9±1.8b 11.8± ±8.8b 12.1±1.2c.116±.2c.2±.2b Mli C Kent 7.9±1.7b 11.± ±13.7b 12.6±.3c.148±.3bc.19±.2b Peru C Pinepple cultivr Smooth cyenne 7.1± ± ± ± ± ±.29 Tnzni O Smooth cyenne 8.3±.7 9.3±.9b 139.9±17.1b 11.4±.7b.143± ±.11b Ugnd O Smooth cyenne 7.5± ±1.3b 15.7± ±4.b.141±.4.942±.23b Cost Ric C Smooth cyenne 8.5± ± ± ±7.3b.127±.8.976±.17b Ghn C Smooth cyenne 6.5± ±.4b 156.1± ±2.1b.145± ±.26b Hondurs C Vlues within columns of the sme fruits with different letters re significntly different (p.5) P = Phosphor, C = Clcium, K= Potssium, Mg = Mgnesium, Fe = Iron nd Mn = Mngnese. Clcium content in mngo cultivrs rnged between 11.3 nd 13.9 mg 1g-1 FW s compred with 8 mg 1g-1 FW found in the study conducted by Cunnighmet l. (21). There ws slight vrition of clcium between orgniclly nd conventionl cultivted mngo cultivrs (Figure 3), which shows tht the cultivtion methods could influence the clcium content of the mngo fruits. In pinepple smples, Clcium content rnged between 7.1 nd 11.3 mg 1g-1 FW. In study crried out by Cunnighm et l. (21), 9 mg 1g-1 FW in pinepple fruits ws observed. Clcium content ws 2% higher in orgnic thn in conventionlly produced pinepple fruits. The clcium content ws found to be higher in orgnic thn conventionl crops (Mgkos et l., 29). Mgkos et l. (29) noted tht climtic fctor my influence the vrition of nutrient levels in products even when other vribles re controlled, which my lter result in difficulties in compring the products. Orgnic pinepple hs shown to posses significnt higher clcium content thn conventionl (p <.5). Gstol nd Domgl-Switkiewicz (212) lso found the contents of clcium to be higher in orgnic thn in conventionl fruits. The cultivtion prctices could influence the chemicl composition of fruits; the vrition in their contents cn even occur within similr vriety (Sturm et l., 23; Lee et l., 23). Potssium content rnged between nd mg 1g -1 FW in mngo cultivrs, Cunnighm et l. (21) found 16 mg 1g -1 FW in mngo fruits, which is close the rnge found in this study. Potssium contents ws1% higher in orgnic thn conventionl produced mngo

12 Phosphorus in mg 1g-1 FW Mgnesium in mg 1g-1 FW Potssium in mg 1g-1 FW Clcium in mg 1g-1 FW Jfo et l p >.5 16 p < b p < p > b p > b p < p < p > b Conventionl Mngo Orgnic Conventionl Orgnic Pinepple Figure 3. Mcro minerl contents (mg 1g -1 FW) in conventionl nd orgnic mngo (n=12) nd pinepples fruits (n=16). Vlues with different letters re significntly different (p.5).

13 423 Afr. J. Agron. cultivrs (Figure 3). It hs been noted tht orgnic plnts hve reltively lrger root-blls to bsorb wider vriety of nutrients thn chemiclly fertilized plnts, due to the fct tht the concentrtion of potssium ffects wter uptke from the soil nd wter retention in the plnt tissues. Another fct is tht mcronutrients re less redily vilble in orgnic system thn in conventionl, so root systems of plnts in orgnic system must grow lrger to tke up nutrients (Prsd, 28). Furthermore, roots of plnts grown in orgnic griculturl system hve wider rnge to ccess sufficient nitrogen, phosphorous nd potssium. As result, in frms tht re mnged orgniclly, plnts come into contct with more micronutrients, such s iron nd mngnese, thn the smller root-blls of plnts in conventionl griculturl system (Prsd, 28). In conventionl frm, the vilbility of fertilizer nutrients in the soil is high long with lots of wter, s result, roots re likely to proliferte less thn under orgnic conditions in order to bsorb dequte nutrients (Worthington, 21). Potssium contents do not vry significntly between conventionl nd orgniclly produced pinepple fruits. It hs been noted in some plnts tht potssium fertilizers could reduce the content of mgnesium nd indirectly content of phosphorus, nd when soils re provided with potssium, the bsorption of mgnesium by the plnt is reduced. This is due to the fct tht bsorption of phosphorus depends on mgnesium, which mkes phosphorus to be less vilble. In conventionl systems, potssium fertilizer dissolves redily in soil wter, providing crops with n dequte supply of potssium, while orgnic systems soils tend to hold more moderte nd vilble quntities of both potssium nd mgnesium round the root zone (Worthington, 21). Mngo hs been shown to posses mgnesium content of between 12.1 nd 16.6 mg 1 g -1 FW s compred with 1 mg 1g-1FW found by Cunnighm et l. (21). Mgnesium content ws on verge, tht is, 8.3% higher in orgnic thn conventionlly produced mngo cultivrs. Worthington (21) found tht crops grown in orgniclly mnged frms hve 29.3% higher content of mgnesium thn crops grown in conventionl griculturl system, nd this could be ttributed to the fct tht in orgnic frming, soil orgnic mtter is involved in nutrient cycling by supplying nd holding nutrients, lso more efficient in holding wter (Worthington, 21). In mngo fruits mgnesium content vried significntly mong mngo cultivrs, where by cultivrs Viringe nd Dodo hve been shown to hve higher mgnesium content of 16.6 nd 16. mg 1g -1 fresh weight, respectively, nd in one loction cultivr Kent hs shown to hve mgnesium content of 16.2 mg 1g -1 fresh weight. This my show tht the levels of mgnesium content in mngo fruits could be influenced by type of cultivrs nd loction. Pinepple ws found to hve mgnesium content of between 9.6 nd 12.4 mg 1g -1 FW s comprd with 13 mg 1g -1 FW found by Cunnighm et l. (21). Mgnesium content ws with verge 12.3% higher in orgnic thn in conventionlly grown pinepple fruits. In orgnic nd conventionl griculturl systems, potssium is presented differently to plnts. In conventionl griculturl systems, potssium dissolves redily in soil when dded with potssium fertilizers, resulting in high mount of potssium in crops, while for soil mnged in the orgnic griculturl system, the root zone of the crops tends to hold moderte mounts of both potssium nd mgnesium (Worthington, 21). The iron contents mong mngo cultivrs rnged between.116 nd.175 mg 1 g -1 FW, which ws slightly below.2 mg 1 g -1 FW found by Cunnighm et l. (21). The iron content vried significntly mong the mngo cultivrs, lthough vrition between conventionl nd orgniclly produced mngo fruits ws not significnt (Figure 4). There ws significnt vrition in terms of iron content between orgnic nd conventionlly cultivted mngo cultivrs. Iron content ws 3.1% higher in conventionl thn in orgnic mngo, which ws not significnt (Figure 4). Gstol nd Domgl-Switkiewicz (212) found in their study tht species nd frming method hs effect on minerl content of fruit juices. A comprtive studies conducted by Worthington (21) nd Fliessbch nd Mäder (21) showed tht higher levels of minerl element, such s iron, mgnesium nd phosphorus, in orgnic rw mterils were influenced by higher levels of microorgnism in the soil. In pinepple, iron content rnged between.127 nd.145 mg 1g-1 FW, which is slightly below.2 mg 1g-1 FW (Cunnighm et l., 21). Orgnic pinepple when compred with conventionl pinepple fruits ws shown to hve 2% higher content of iron (Figure 4). Gstol nd Domgl-Switkiewicz (212) found tht the cultivtion system hs no influence on iron juice content. Orgniclly mnged soils hs been found to hve more microorgnisms (Worthington, 21).These micro-orgnisms produce severl compounds, such s citrte nd lctte, tht combine with soil minerls nd mke these minerls more vilble to plnt roots, especilly iron, which is found in mny soils in dequte mount but in n unvilble form. Method of frming hs been shown to hve significntly higher minerl content in orgniclly grown thn non-orgniclly grown fruit nd vegetbles (Holden, 21). Mngnese content mong the mngo cultivrs rnged between.19 nd.38 mg 1g -1 FW, which correspond with.27 mg 1g -1 FW indicted by Wojciech et l. (29). Mngnese content vrition ws not significnt in both conventionl nd orgniclly cultivted mngo cultivrs, similr observtions ws noted by (Liron, 21) who found tht the production systems could not significntly influence vrition of the minerl

14 Mngnese in mg 1g-1 FW Iron in mg 1g-1 FW Jfo et l p >.5.2 p > p > p < b Conventionl Orgnic Conventionl Orgnic Mngo Pinepple Figure 4. Micro minerl contents (mg 1g -1 FW) in conventionl nd orgnic mngo (n=12) nd pinepples fruits (n=16). Vlues with different letters re significntly different (p.5). composition of pple fruits. It hs lso been reported tht minerl contents in strwberry ws not ffected consistently by orgnic cultivtion (Hkl et l., 23). Mngnese content vried significntly (p.5) mong pinepple fruits from different cultivtion nd loction. Mngnese content ws 32.8% higher in orgniclly thn conventionlly produced pinepple fruits; this shows the effect of method of production nd loction on mngnese content of pinepple fruits. In orgnic griculturl prctice, soil hs high orgnic substnces, which serves s cheltes for micronutrient metls. These cheltes re soluble orgnic compounds tht bind metls nd increse their solubility nd vilbility to plnts (McCuley et l., 29). The results showed tht the pinepple fruits with mngnese content rnged between.942 nd mg 1g -1 FW, which is close to.927 mg 1g -1 FW reported by Wojciech et l. (29). In fresh fruits nd vegetbles, the composition of minerls fluctutes due to pre-hrvest fctors, such s soil fertility, which includes ph nd nutrients vilbility to plnt, soil moisture content, growth temperture nd griculturl prctices determined by the mount nd timing of fertiliztion nd irrigtion, the ppliction of plnt growth regultors, pruning nd thinning of tree fruit species (Wojciech et l. 29). A study by Crisosto nd Mitchell (22), it ws shown tht, in most cses, these prctices hve been developed to increse yields nd improve qulity of products suitble for humn helth nd the prctices lso hve influence on post-hrvest life or flvour qulity of horticulturl crops. Normlly, fertilizers re pplied with the im of rising nutrient levels for the successful growth of the crop, nd to mintin the fertility of the soil.

15 425 Afr. J. Agron. Conclusion This study shows tht the vritions in nutritionl chrcteristics of fruits could be influenced by griculturl prctice, geogrphicl loction nd genetic vrition between cultivrs. Mngo nd pinepple fruits from different loctions showed significnt vritions in their glucose, fructose, sucrose nd totl soluble solids contents. Orgnic cid, titrtble cidity nd ph levels in the fruits vried significntly mong the mngo nd pinepple fruits from different loctions. There were significnt vritions in minerl contents mong pinepple nd mngo fruits produced in different loctions. These results indicte the influence of loction on nutritionl sttus of fruits. Sugr, minerls nd orgnic cids contents vried mong different cultivrs of mngo fruits, indicting tht there is correltion between type of fruit cultivrs nd qulity ttributes of the fruits. The type of cultivtion my influence vribility in the qulity of fruits components in terms of sugr, minerl nd orgnic cid contents. It cn be concluded from the study tht levels of nutritionl vribles of mngo nd pinepple of the sme cultivr nd sme climtic condition could significntly be ffected by the type of griculture prctices influencing the rtes of vilbility of plnt nutrients. Orgnic frming promotes production without the use of synthetic chemicls or fertilizers while enhncing soil composition nd promoting biodiversity. This type of production relies on ecosystem services to mintin the integrity of the lndscpe while still producing sufficient yields. Conventionl frming uses synthetic chemicls nd fertilizers to mximize the yield of prticulr crop or set of crops, whereby systems requires significnt mount of chemicl nd energy input nd wekens the ecology of lndscpe. It is importnt to highlight the fct tht the fruits studied differed in soil composition, geogrphy, nd rottion systems, which hs contributed to vrition of their qulity ttributes. ACKNOWLEDGEMENT The uthors grtefully cknowledge the deprtment of crop science division of qulity product under Georg August University- Gottingen. REFERENCES Abu-Smr A, Morris JS, Koirtyohnn SR (1975). Wet shing of some biologicl smples in microwve oven. Anl. Chem., 47: Altieri MA, Nicholls CI (212). Sustinble Agriculture Reviews. Sustinble Agriculture Reviews (Vol. 11). Andrews PK, Fellmn KJ, Glover JD, Regnold JP (21). Soil nd Plnt Minerl Nutrition nd Fruit Qulity under Orgnic, Conventionl nd Integrted Apple Production Systems in Wshington Stte, USA. Act Horticult., 564: Anz, Mike, Rig, Ptrick, Grbisu C. (26). Effects of vriety nd growth seson on the orgnoleptic nd nutrionl qulity of hydroponiclly grown tomto. J. Food Qul., 29(1): AOAC (1998). Officil Methods of Anlysis of AOAC Interntionl. Assocition of Officil Anlysis Chemists Interntionl, CD ROM. Arredondo M, Núñez MT (25). Iron nd copper metbolism. Mol. Aspects Med, 26: Brt J, Pilr CM, Gusek T, Sidhu JS, Sinh N (26). Hndbook of Fruits nd Fruit Processing. Boyer JS (29). Cell wll biosynthesis nd the moleculr mechnism of plnt enlrgement. Functionl Plnt Biol., 36: Crvlho CRL, Rosseto CJ, Mntovni DMB, Morgno MA, Cstro JVBN (24). Evlution of mngo cultivrs selected by Instituto Agronômico de Cmpins compred to others of commercil importnce. Rev Brs Frutic, 26: Cohen AJ, Roe FJC (2). Review of risk fctors for osteoporosis with prticulr reference to possible etiologicl role of dietry slt. Food Chem. Toxicol., 38: Colric, M., Veberic, R., Stmpr, F nd M. Hudin, M. (25). Evlution of pech nd nectrine fruit qulity nd correltion between sensory nd chemicl ttributes. J. Sci. Food Agri., 85: Crisosto CH, Mitchell FG (22). Pech, nectrine nd plum. In: Kder A.A. (ed.). Posthrvest Technology of Horticulturl Crops. Specil Publiction No University of Cliforni, Division of Agriculture nd Nturl Resources, Oklnd, Cliforni, pp Cunnighm JH, Millign G, Trevisn L. (21). Minerls in Austrlin fruits nd vegetbles- comprison of levels between the 198s nd 2, Food Stndrds, Austrli nd New Zelnd, pp Degree P, Advisor M, Chen S, Amit K (212). Deprtment of Agronomy Ntionl Chung Hsing University 博士學位論文 Disserttion for the Doctor of Philosophy Degree. DiMggio LA, White KE, Econs MJ (2). Disorders of phosphte metbolism. Endocrinol. Metb. Clin. North Am., (29): Fliessbch,A nd Mäder, P. (21). Microbil biomss nd size density fctions differ between soils of orgnic nd conventionl griculturl systems. Soil Biol. Bioch., 32: Forney, C. F., Klt, W., & Jordn, M. A. (2). The composition of strwberry rom is influenced by

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