Preservation of Cucumeropsis 1I1(IIIIIii Nuud-Holl seeds

Indian /'1'),10/'01'"

33 (2) : 119-102 (20\)0)

Preservation ADEKUNLE, 1J""al'III"''''

of Cucumeropsis

A.A, AND UMA, NGWANMi\

0/ fl,iIO"Y

and Mtcrobiology,

Nuud-Holl

1I1(IIIIIii

seeds

U.

University of I.ag',)!.

l'(/bll-f.t1~"J.

!l'1J:I'r/O

AnSTltACT

t The preservatlen of ('/I('/lIII"WpS/,f monni! Nllud-lIull ('':\:u\i' melon) seeds by IIUllil'ullllilll! Iht Itruperature, relntlve hUnlldlty and Iype of 'tlltll~e "lIS urtlt" out. run\:1 wcr e Jllllhu\:t'nlc on melon Hl'lh sl"n,1 1I hi\!h retntlve hUllIldltles of IOOV. anll ~11·/.,but not I1t lu\\'u humidity hetween () .1111 !\~'/.,nlsuse IIIlnirl'\\t:,1 on lilt "H'I,,"

"ft'ds Rt tt''''''frll~Ute or 20°C and J7°C where AS 110 dinll\t' lnchlence ,•• s nhverve d .t ttnlpu.lurtS !i-lUoe .".1 ~U"C I>I~use IlIchlcnce ,,"rled ",'lIh sto't,lIge condition. St't'ds stored In the OHn (~lJoC 2; IUt 0%) h'ad IIU rUlIl!al i\"lalt' IIrtcr 11 mOllths 'stersge. Those seeds storl'd in the Jlllrdtn (27-.U~C; IU l 76-90%) and IlhorAtur) ~htlr (lH"C-JO°C; • JUt. 80-117%) for the SAme pertod hnll fUII!!nl lsotate which were .tncnl III tilt' hl'l:inllinK uf Slllll':('. 'I hcr e "u In increase III tilt' rrrct'IItRJle Infectivity of the melon sCflh u the slor .I!t' I'l'tiod Incre aserl, for seeds sltl!'t'd in lilt' I!,,"kn nnll lnbnrutury. Set'tI, stored In the oven 'Hre nnt-lnfccterl "I tilt' rllll Itf 11 /Ilonlh, storl.:e I'cr iud. lJn~hdl"11 /IIdUII s('tlh were tess Infected with fungi "hen compnred to shelled seeds.

*

Key wllnh

: l'rcservntion,

Cucumeropsis

m,lIIlIl; seeds, temperature.

ClI(,II//1l'rol'J;,\' //1(//",;; Nuud-l loll (' Egus]' melon) is variety of melon seeds available in Nigeria (I.owc and Soludoye, 19K9), Economically, C. //101/1';; seeds and its

It

oil serve ns n rich source of dietary energy. 1 he melon soirp ls a favourite of many West A Iricuns. 'I he seeds could also be tried and chewed as snacks (Abaclu, et al., 11)79), Melon seed oil has the potential for being used us a base for soap and body cream production. Biochemically healthy C, munnii seeds contain 53% oil, 3.K% protein and 1% carbohydiatc (Courscy, 1964; Adekunlc, 19(7), Seeds are attacked by fungi, bactet iu, insects, viruses nnd other plant pathogen during storage (Chrlstcnsen. 1957). Market sampling of CIlt'/lI/I' " opsis numnil revealed that nineteen fungi were involved in its deterioration during storage [Adckunlc. 1997), Seed storabllity depending on container is consider ably inIluenced by Ihe kind of variety of seeds (Lever, 1990), The umount or moisture in the seeds is one "I' the must important luctors Influencing seed viahility dill ing stnrnge. 'I he safe moisture content, however, depends upon storage length, type of storage structure, kind or variety ul' !,,'ed~, U.II.! type of puckuging milte. iul used (Nccrguar, 1(77), Besides meisturc environmental conditions, viz. temperature and Rel;Itive humidity) also intlucnce the Incidence of fling! on seeds. Aboabla and Amusike (1991) studied the effect of some storage cmulit ions on the growth of three fungi on melon seeds. I Iowcvcr, precise informntion is lacking (/11other fungi

rt:bliH humidity.

involved in post-hur vcst Jell,.iu.ali"",,r( ',,, /1'11"'"1'.''' 11/(//11111 ~l·l'lls. In lite present ~luJ) the IlIne. \ ,1111111 "r CIICI/lIIl·'IJI,.Il.f 11/(///111;seed by '";lIliplIl.llillg Ihe f{ 11. illltl temperalure \\a~ umlcrtukvu and the gll)\\ lit 01 thirteen Itlllgdl pathogens of the ~t:eJ) was It:lIlI d,,1 I he , clalil'"~hil' O.:l\\C':11 IlK: biochcm« JI plup,'rlln IIf infected seeds and varitive humiduics, the dfl'l:1 III durutiun .1IIJ 1)l'e or storugc UII Ihe iucidciu c III fUllbi uud moisun e come tof rl cshly hill \ nll:J ( 'Ill 1I/lILI"/'1" mUIIII;; seeds were also invcstig.ncd I\'AU:JU,\LIj

ANU METIIOUS

Enl'ct of. l'IlIli\ e hu IIIitlit), onlh·tu imHtilln uf IItllncinll} Innoculatcd Cucumerop»!« 11/.11/11;; ~1'l:lh: Funga! deterioration of melon SI'd,,,,,:

alld thl (""'elll,,1

lI,d""

seeds

-------------------------------------------------------~

124

lndlan Phytopathology

IVul.

gain 01 91 and 100% humidities. Infected seeds behaved differently, they lost weight at all R.II tested. For all fungi, (Table I and 2), except Aspergillus wentii, slight increase in proteins of infected seeds were recorded for seeds kept at 91 and 100% humidities only. On the other hand, seeds infected with Aspergillus wenti! hod 0 decrease in protein content at 91 and 100% humidites. There were no changes in the carbohydrate content of seeds used .for control in nil the relative humidities but sharp increases were observed for nil Infected seeds kept at 91 and 100% humidities. At relative humiditles, 0, 10 and 32.5% the carbohydrate content of nil infected seeds did nol change. A 11 infected seeds nt 91 and 100% humiditics had a decrease in oil content. There was no change in oil content of infected seeds at 0, 10 and 32.5% R.II. lhe seeds used fur control had no change In oil content for all humiditics tested. F.rreel ur relutlve humidity and temperature IlIltlwl!enldty or nrlecnrungllllsolates on Cncumcropsls "',11I,,11 seeds In the absence moisture

on the or

Generally, there were reduced percentage pathogenicity caused by the fungi on melon seeds stored ill l'olythcnc (1'1.) bags than in semi-liquid agar (LA) plates. The percentage pathogenicity by all the fungi \\ as reduced in unshelled seeds than shelled seeds ut 91. 100% IUI; nnd 5-10, 28-31 and 37"C lelllpclallllc ,·b· pvrgillus 1\'('1/1;; and Taluromyces wet e not palhogcnic on unshelled seeds under all stored conditions used here. Percentage pathogenicity was below 20% for infected seeds kept at 5-1 o"e except seeds infected with A.vl'er~;lIl1j jlm'lIs and Rhizopus CJr)'ZlJI!wh ich showed I'a~hogenicity above 35%. The fungi were must pathogenic nt room temperature (28-31 "C), Only A.ji/llli~IIIII,f \\'1I!1 patlw!!enic on shelled seeds at •• but not pathogenic on unshcllcd seeds. The seeds were gcuing burnt hy the Rlh day of the experiments at 4Y'C. Also at -lOT. only Aspergillus fumigatus had high pathogen icily .

sac

UlSCllSSION

I In thi!! study, moisture content of melon seeds was related to the relative humidity of Ihe cuvh oumcnt ngreelng with earlier observation of Mad,,,y (1%7) on other seeds. The oil content of infected seeds decreased at 91 and 100% humidity. There was also all increase in carbohydrate content Ior jhese humlditics. it that the lilllglll enzymes broke down the oil eventually into monosacchnrldes causing increase, which is then absorbcd hy the fllnl;lIs for Its metahulic activity. '1his obscrvution 15similar to the work of Adckunlc and Umn

SJ(2)

2t/UUI

(1997) on the b.iochemistry of fUllgal infected melon seeds. 1 here was a greater fungal activity at high humidities of 91 and 100% than low humiditics of 0, I U and 32.5% where there was no fungal activity. '1 hest: results confirm earlier reports by Oycniran (11)8U). and Sillgh and l'rasad ( 11}83). Seeds stored in the oven (·IU''C) had reduced moisture content accompanied with reduced number of Iung] and infectivity on the seeds compared with seeds stored in the garden und luborutor y. This probably shows that the moisture content of seeds favoured the incidence of fungi and their infectivity on melon seeds. Invariably, the relative humidity of the environment where melon seeds ale ~Illlcd is importaut in 1'1cset v ing the seeds. Obse r vutious

in this

study

also

shows

that

uushcllcd melon seeds stored in b"g~ OIl·\uT \\ ill be the 11I051advisable means of preserving melon !>ceu\. Melon seeds can be stored 01 5-1 onc a~ suggested b)' Abouba and Amasike (1991). but seeds at these ICIIIperuturcs were water soaked and swollen. '1 huv, this tcinpcrann e (5-1 O"C) is not good enough for IUl'g I'er iud (2 months) of storage. A"ano and OSlI (11)!)1l) observed shrivelling and water snaked uppcarance on Onion bulbs at 5-IO"C alter three monlh~ uf sllll.h,:t:. '1he)' explained Ihat this was due III culd illjlll) Cold injUly on rnclon seeds might also hc Inl'IlI"I"!.: IClr Ib heing water soaked and swollen w h•..1I~llIIcJ ill 5·ICI t ' f\llIIe IlIlIgi were isolated liulII ('1/"11''''/''/'\1, /11,1111/" seeds stut cd in the garden than in lite uv cu (.1lI l' I. shuw iug Ihal the seeds in the g;lIden plll..l'llllf1 IlIlll:1 li om its env iron IIIcut. 1 his supports K 197.1) llh~"'Ivatinn 11t,,1 produce picked up inlcction hUIII uthvr mouldy products and fungal sJ10ln I'le~elll ill the envinnunent. '1he fungi isolated lunu seeds stored in the liven (-IO"C) were isolated durin]; the krllll'ntalilln pel iod of the seed. 1 his means thal Ihc\c hlllgi 11I11\1 ha~ c been gol dUI ing processing of the secds or (In the Iicld. '1 hcretore, the elimination ot tllllgi 1'111111 melon seeds dUI ing processing prior to 5101age is impurt.nu 10 improve preservation or the seeds.

""U (

'I he lime uf incidence of ill~ccls lIlI the seeds with the time the stored melon !>eeJ~ became powdery. The pi escnce of in\cclS on IIIcI'lIl seeds during these investigations confirms U}enilall\ (IlJI!U) slalelllent Ihal storuge lo~~es IIIc 1I0t dill' hI a pm ticular hiulogicai ngcncy. Ther di'r c, the pow 11..-1)ncvs of the seeds as observed in this sllllly mighl IIlII he due 10 the presence of insects alone, '1 he oven (.'0' C) \\a~ able 10 prevcut the presence of insects 1111 uughout the illvesli~:tlioll period.

coucspondcd

lrorn

these

lnvestigatlons,

{'I/CI/II1