weight loss_.doc

Hort 418/518Postharvest Technology LabAssigned: October 8th, 24!"e: October 2#th, 24Water LossIntroduction:$oist"re loss is a %a&or ca"se o' red"ced ("ality in )erishable co%%odities*+t %ay res"lt in ,ilting, %ealiness, 'laccidity, so'tening, shriveling, )itting, or other te-t"ral changes, de)ending on the co%%odity*.-tensive ,ater loss can lead to cell deco%)art%entation, lea/age, colla)se and death*Other e''ects can be )hysiological in nat"re, s"ch as enhanced ethylene synthesis in ,ater0stressed )re0cli%acteric bananas 1Litt%an, 1#223*There are %any 'actors that a''ect loss o' ,ater 'ro% a co%%odity, incl"ding:1* 4iological 'actorsa* 5 ,ater in co%%odityb* 6"r'ace to vol"%e ratioc* 7at"re o' )rotective s"r'ace2* Physical 'actorsa* 8elative h"%idity 18H3b* Te%)erat"rec* Press"red* Air %ove%ente* Light 1light sti%"lates sto%ates to o)en in so%e )lant organs3$ini%i9ing ,ater loss 'ro% a )erishable o'ten re("ires co%%odity treat%ents and environ%ental o)ti%i9ation, incl"ding:1* Treat%entsa* 8a)id cooling a'ter harvestb* Avoid da%agec* :oatings 1e*g*, ,a-es, etc*3d* Pac/aginge* 8ed"ce s"r'ace area 1re%ove leaves, etc*32* .nviron%entala* Lo,er te%)erat"reb* +ncrease 8Hc* 8ed"ce air %ove%entd* 8ed"ce te%)erat"re 'l"ct"ations 1gradients3There are ti%es ,hen signi'icant ,ater loss can be desired*;:"ring; is a ra)id ind"ced %oist"re loss that is bene'icial*.-a%)les o' the c"ring )rocess incl"de shell hardening o' c"c"rbits, ginseng)re)aration, seed shells, and o"ter scales o' onions and b"lbs*1Objectives :To observe %oist"re loss over ti%e and its e''ect on a co%%odity*To learn the "se o' the sling )sychro%eter and hygrother%ogra)h*Procedure:6t"dents ,ill divide the%selves into )airs*.ach )air ,ill select a co%%odity, divide it into 'o"rths,and ,eigh and record each sa%)le se)arately 1sa%)les ,ill not be o' identical ,eight3*Place t,o sa%)les into )a)er bags and the other t,o sa%)les into )er'orated )oly bags, then sta)le the% sh"t*$ar/ the bags so that yo" can identi'y the%* Place one )oly and one )a)er bag in the cold roo%*Place the other t,o bags in roo% 22 on a ,agon*ra)h the 5 ,eight loss 15 ,t* loss on a vertical a-is, ti%e on hori9ontal a-is3 and note yo"r observations on the a))earance o' yo"r co%%odity* Ass"%e that all the ,eight lost ,as ca"sed by the loss o' ,ater*.-a%)le: initial ,t* 5 g ,t a'ter 1 ,/ 4# g,t loss 1 g5 ,t* lost 0 1 g - 15 ? 25 H2O loss at end o' ,/ 1!eter%ine the relative h"%idity o"tside and inside o' cold roo% @A "sing a sling )sychro%eter*The techni("e ,ill be de%onstrated*Observe the de%onstration o' the hygrother%ogra)h and "nderstand ho, it ,or/s*Conclusion:era/an "dara e* :ahaya 1cahaya %erangsang sto%ata "nt"/ %e%b"/a )ada bebera)a organ tana%an3Fsaha "nt"/ %e%ini%al/an /ehilangan air sering /ali %e%erl"/an )erla/"an /h"s"s )ada/o%oditas dan o)ti%asi ling/"ngan, diantaranya: 1* Perla/"an /h"s"s :a* Pendinginan ce)at setelah )anen b* Hindari /er"sa/an c* Pe%berian la)isan /h"s"s 1%isalnya, lilin, dll3 d* Penge%asan e* $eng"rangi l"as )er%"/aan 1%enghilang/an da"n, dll32* Ling/"ngan a* $en"r"n/an s"h"b* $ening/at/an /ele%baban relative 18H 3c* $eng"rangi sir/"lasi "darad* $eng"rangi 'l"/t"asi s"h" "dara 1gradien3Ada /alanya /ehilangan air yang signi'i/an &"str" diingin/an* ;:"ring; ata" )engeringan secarace)at adalahhilangnya/ele%babansecarace)at yang&"str"ber%an'aat* :ontoh)rosesc"ring%eli)"ti )engerasan cang/ang c"c"rbits, )ersia)an ginseng, /erang bi&i, dan /"lit l"ar ba,ang dan"%bi0"%bian*Tujuan :Fnt"/ %enga%ati hilangnya /ele%baban dari ,a/t" /e ,a/t" dan e'e/nya )ada /o%oditas* Fnt"/%e%)ela&ari )engg"naan psychrometer sling dan hygrothermograph*=Prosedur :6is,a a/an di/elo%)o//an dala%bebera)a reg"* 6etia) reg" a/an %e%ilih /o%oditas,%e%baginya%en&adi e%)at, /e%"dian%eni%bangdan%encatat setia)sa%)el secarater)isah1berat sa%)el tida/ a/an identi/3* Te%)at/an d"a sa%)el /e dala% /antong /ertas dan d"a sa%)ellainnya /e dala% /antong )oli berl"bang, /e%"dian segel /antong terseb"t dengan sta)les/ /li)*Tandai /antong terseb"t sehingga Anda da)at %engidenti'i/asinya* Te%)at/an sat" )oli dan sat"/antong /ertas di r"ang dingin* Te%)at/an d"a tas lainnya di /a%ar 22 di geroba/*Ti%bang dan%e%eri/sa /er"sa/an /o%oditas )ada a/hir %ingg" 1, 2, dan =* 4"at gra'i/ )en"r"nan )ersentaseberat 15)en"r"nan berat*)ada s"%b" verti/al, ,a/t" di s"%b" horisontal3 dan catat hasil)enga%atan Anda )ada )ena%)a/an /o%oditas*As"%si/an bah,a se%"a berat yang hilangdisebab/an oleh hilangnya air*:ontoh: berat a,al* 5 gberat setelah 1 %ingg" 4# g/ehilangan berat 1 g5 berat* hilang 0 1 g - 15 ? 25 /ehilangan H2O )ada a/hir %ingg" 1$enent"/an /ele%baban relati' di l"ar dan di dala% r"angan )endingin @ A %engg"na/an)sychro%eter sling* Te/ni/ ini a/an dide%onstrasi/anA%ati de%onstrasi )engg"naan hygrother%ogra)h dan )aha%i cara /er&anya*Kesimpulan:Dehilanganair %er")a/ansalahsat"'a/tor "ta%a/er"gian)asca)anen* !engande%i/ian,)enting "nt"/ da)at %engenali dan %encegahnya* Fnt"/ it", Anda har"s %e%aha%i 'a/tor0'a/toryang terlibat dan da)at %e%ani)"lasi %ere/a "nt"/ %e%ini%al/an hilangnya /ele%baban*!ala% %en"lis la)oran ini, sa%)ai/an hasil )enga%atan anda dan as"%si/an tentang a)a yangter&adi*:atat )erbedaan antara 8H l"ar dan di dala% r"angan yang dingin, dan beri/an /o%entaranda* Dait/an /ondisi )er%"/aan )ada /o%oditas anda dengan hasil a/hir observasi, danbagai%ana )eran /ondisi )er%"/aan /o%oditas )ada )eng"rangan /ehilangan air 1c"/"))enga%atan vis"al sa&a3*4