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Kafirin biofilm quality : effect of sorghum variety and milling fractionsDa Silva, Laura Suzanne 02 September 2005 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc (Agric) Food Sience and Technology)--University of Pretoria, 2005. / Food Science / unrestricted
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Assessment of precooling technologies for sweet cornCortbaoui, Patrick January 2005 (has links)
Sweet corn is classified among highly perishable horticultural commodities. Thus, it can be deteriorated rapidly after harvest resulting in high loss and poorer produce quality. Sweet corn's sugar loss is about four times higher at 10°C compared to 0°C. Precooling, immediately after harvest, has shown to be an effective method to maintain the quality for a wide range of fresh fruits and vegetables during storage. Further, this method leads to reduction in metabolism and respiration rate of the produce, retardation of its senescence, and inhibition of growth of pathogens. In addition to diminishing postharvest losses of the produce, efficient precooling is required for increasing the length of duration of marketing time for better profitability. / Precooling of sweet corn was accomplished by three main methods including forced-air, water and vacuum cooling. Operating parameters such as temperature, pressure, orientation of corn cobs, air flow rate and water flow pattern were defined and studied for optimization. The assessment and comparison of the performance of precooling systems was achieved by determining the effect of these parameters on half cooling time and quality of the produce during storage for 7 and 21 days at 1°C and 90-95% RH. In addition, room cooling method was also tested and compared to the three precooling systems. The use of three sweet corn cultivars was important to compare their quality response to different cooling methods. / Experiments were performed on a lab-scale vacuum cooler and modified forced-air and water cooler systems. The results showed that changing the cob orientation perpendicular to the direction of flow medium, using higher air flow rate in forced-air cooling and immersed water flow pattern in water cooling, can significantly reduce the half cooling time of the produce. Finally, the best method to be recommended for precooling sweet corn is by using hydrocooling which results in superior quality produce and minimum time.
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Postharvest treatments to reduce chilling injury symptoms in stored mangoesTasneem, Azra January 2004 (has links)
The market life of many fruits and vegetables can be extended through storage at low temperatures. Chilling injury (CI) is a major postharvest storage problem for tropical commodities. Storing these products at temperatures below their critical temperature may result in severe physiological disorders known as CI symptoms. Mangoes (Mangifera indica. L) are susceptible to CI when stored below 12 °C. Visual CI symptoms include uneven ripening, surface pitting, discoloration, shriveling and scalding. Research has been conducted to overcome these serious problems using various postharvest treatments such as hot water, methyl jasmonate (MJ) or diphenylamine (DPA) with some reduction of the incidence of CI symptoms in fruits and vegetables. / Experiments were performed to assess and compare the potential of the above-mentioned postharvest treatments to reduce the CI symptoms on mango cv. Kent. The obtained results indicated that MJ- and DPA-treatments gave significantly greater percentage of marketable fruits. / Experiments were also conducted with mangoes cv. Tommy Atkins treated with MJ and DPA before storing at low temperatures (1, 4, 7 and 10°C). The chemical treatments were successful at reducing CI symptoms of mangoes. Fruit decay was reduced during subsequent ripening. MJ-treated fruits had lower mass loss and higher total soluble solids (TSS) than the control treatment. The overall quality of MJ- and DPA-treated fruits was good with lower surface pitting and scalding compared with the control treatment. The best results were obtained at storage temperatures of 7 and 10°C. Both MJ and DPA postharvest treatments can reduce CI symptoms in mangoes cvs. Kent and Tommy Atkins when the mangoes are stored at below critical temperature.
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Postharvest treatments to reduce chilling injury symptoms in stored mangoesTasneem, Azra January 2004 (has links)
No description available.
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Assessment of precooling technologies for sweet cornCortbaoui, Patrick January 2005 (has links)
No description available.
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Leaf blackening of proteasStephens, Iain Andrew 04 1900 (has links)
Dissertation (PhD (Agric))--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Leaf blackening is a particular problem limiting vase life and marketability of
Protea cut flowers. This research investigated suppression of Protea leaf blackening
with a specific focus on Protea cv. Sylvia (P. eximia x P. susannae) cut flowers.
Leaf blackening decreased significantly with decreasing storage temperatures m
'Sylvia' proteas and this was attributed to lower respiration rate and conservation of
carbohydrate. Low storage temperatures were beneficial in short term handling
procedures encountered during airfreight. However, use of low temperatures alone
during the longer sea freight period was unsatisfactory in either maintaining or
extending 'Sylvia' protea vase life. Cooling of 'Sylvia' proteas under vacuum
significantly suppressed leaf blackening and was of greater benefit than forced air
cooling.
Although removal of the uppermost leaves delayed leaf blackening in short term
storage no significant benefit was found for longer storage periods. Girdling directly
beneath the 'Sylvia' protea flowerhead significantly reduced leaf blackening and in
combination with low storage temperatures (O°C) enabled a significant extension in
both storage and vase life of 'Sylvia' proteas.
'Sylvia' proteas did not exhibit a climacteric respiration peak during 96 h storage
at O°C. Exposure to ethylene did not increase Protea leaf blackening or have a
detrimental effect on vase life of either proteas or pincushions evaluated.
No beneficial response to sucrose supplementation was found in 'Sylvia' proteas.
Analysis of the sugar content of both flowerhead and leaves indicated that glucose supplementation might be of benefit and was investigated. Holding solutions of 2.5 %
glucose significantly extended vase life due to a significant reduction in leaf
blackening. Vase life was terminated due to flowerhead collapse instead of leaf
blackening for the first time in 'Sylvia' protea cut flowers. Vase life was significantly
extended by 2:3% glucose pulse solutions and leaf blackening significantly suppressed
with increasing glucose pulse concentration. Solution uptake was facilitated by use of
high intensity PAR lights in the early morning and was attributed to increased stomata
opening and a consequent increase in both transpiration and glucose solution uptake.
The faster uptake of glucose solutions in shoots harvested in the afternoon was
attributed to higher shoot temperatures and consequent transpiration rate to those
harvested in the morning. There was a significant reduction in uptake time with
increasing pulse temperature, which enabled vacuum cooling to be performed earlier
further benefiting storage and vase life extension.
Enclosure of 'Sylvia' proteas in polyethylene (PE) lined cartons did suppress leaf
blackening in non-pulsed shoots. However, this had no practical significance on useful
vase life, which was terminated at this point due to excessive leaf blackening. Water
loss appears to have a minimal influence on 'Sylvia' protea leaf blackening.
Shading at four and three weeks prior to harvest coincided with a period of
significant flowerhead dry mass increase. It is thought that shading at this point,
concurrent with an increased carbohydrate demand by the developing flower head
resulted in a temporary limitation in carbohydrate supply resulting in the appearance of
preharvest leaf blackening. It would appear that proteas do not store large quantities of carbohydrate. Although accentuating winter light conditions by shading did result in a
decrease in carbohydrate content the fact that carbohydrate content was already low
precluded shading from having a significant impact on postharvest leaf blackening.
The finding that glucose was beneficial in extension of both storage and vase life
of 'Sylvia' proteas directed research into its use for other Protea and Leucospermum
cut flowers. Significant differences in the response to glucose supplementation were
found in both Protea and Leucospermum (pincushions). The significant difference in
sensitivity to glucose concentration in 'Pink Ice' proteas (phytotoxic at 2:4%) and
'Susara' proteas (no apparent toxicity), in conjunction with a lack of response in
'Cardinal' proteas, a hybrid from the same parents as 'Sylvia' indicates the need to
direct future research to individual cultivars. Glucose supplementation had no
beneficial effect on vase life of 'Scarlet Ribbon' and 'Tango' pincushions, whilst
significantly extending vase life of 'Cordi', 'Gold Dust', 'High Gold' and 'Succession'
pincushions. / AFRIKAANSE OPSOMMING: Blaarverswarting is 'n spesifieke probleem wat die vaasleeftyd en die
bemarkbaarheid van Protea snyblomme beperk. In hierdie navorsing is ondersoek
ingestel na die onderdrukking van Protea blaarverswarting met spesifieke fokus op die
snyblomme van die kv. Sylvia (P. eximia x P. susannae).
Die voorkoms van blaarverswarting by 'Sylvia' het merkbaar afgeneem tydens die
verlaging van bergingstemperature. Hierdie afname is toegeskryf aan 'n laer
respirasietempo en die behoud van koolhidrate. Lae bergingstemperature in die
korttermyn hantering van die produk tydens lugvrag was voordelig. Die gebruik van
lae temperature, slegs tydens die langer verskeepingsperiode, was egter onbevredigend
vir vaasleeftyd verlenging en onderhoud van 'Sylvia' protea. Die afkoeling van
'Sylvia' proteas onder vakuum het blaarverswarting in 'n groot mate onderdruk en het
beter resultate gelewer as geforseerde lugverkoeling.
Alhoewel die verwydering van die heel boonste blare blaarverswarting by
korttermynopberging vertraag het, het dit geen merkbare voordele vir langer
bergingsperiodes ingehou nie. Ringelering direk onder die blomkop van die 'Sylvia'
protea het blaarverswarting aansienlik verminder, en saam met lae bergingstemperature
(O°C) het dit 'n merkbare verlenging in beide die bergingstyd en die vaasleeftyd van
'Sylvia' proteas teweeggebring. 'Sylvia' proteas het geen klimakteriese respirasiekruin tydens 'n bergingsperiode
van 96 uur teen O°C getoon nie. Blootstelling aan etileen het nie die Protea
blaarverswarting laat toeneem of 'n nadelige effek op die vaasleeftyd van die proteas of
speldekussings wat geevalueer is, gehad nie.
Geen voordelige reaksie op sukrose-byvoeging is in 'Sylvia' proteas gevind nie.
'n Analise van die suikerinhoud van beide die blomkoppe en die blare het aangetoon
dat 'n glukose-byvoeging moontlik voordelig kon wees, en hierdie aspek is ondersoek.
Met stooroplossings van 2,5 % glukose is die vaasleeftyd aansienlik verleng omdat daar
'n merkbare afname in blaarverswarting was. Vir die eerste keer in die geval van die
'Sylvia' protea, het die vaasleeftyd van die snyblomrne tot 'n einde gekom omdat die
blornkoppe uitmekaar gebreek het en nie omdat blaarverswarting ingetree het nie. Die
vaasleeftyd is aansienlik verleng met ~ 3% glukose-pulsoplossings, en blaarverswarting
is merkbaar onderdruk met die verhoging van hierdie oplossings se
glukosekonsentrasie. Die opname van die oplossings is gefasiliteer deur hoe intensiteit
PAR (fotosinteties-aktiewe radiasie) ligte vroeg in die oggend, en is toegeskryf daaraan
dat meer huidmondjies oopgegaan het. Dit het gelei tot 'n toename in transpirasie en
'n toename in die opname van die glukose-oplossing. Die feit dat glukose-oplossings
vinniger opgeneem is deur lote wat in die middag geoes is, is toegeskryf daaraan dat
loottemperature dan hoer is as soggens en gevolglik lei tot 'n vinniger
transpirasietempo. Daar was 'n merkbare afname in die opnametyd wanneer die
temperatuur van die pulsoplossings verhoog is. Vakuumafkoeling kon dus vroeer
toegepas word, wat 'n verlenging in bergingstyd en vaasleeftyd tot gevolg gehad het. Verpakking van 'Sylvia' proteas in kartonne wat met poli-etileen uitgevoer is, het
blaarverswarting van lote wat nie aan pulsering onderwerp is nie, onderdruk. Hierdie
maatreel het egter geen praktiese waarde met betrekking tot vaasleeftyd nie; die
vaasleeftyd het tot 'n einde gekom as gevolg van omvangryke blaarverswarting. Dit
lyk asof waterverlies weinig invloed het op die blaarverswarting van' Sylvia' proteas.
Die vermoede bestaan dat lae koolhidraatvlakke proteas ontvanklik maak vir
blaarverswarting. Alhoewel die beklemtoning van winterligtoestande deur
beskaduwing gelei het tot 'n afname in koolhidraatinhoud, was hierdie inhoud reeds
laag en blaarverswarting na die oes is nie beinvloed nie. Beskaduwing tydens die vier
en drie weke voor oestyd het saamgeval met 'n tydperk van aansienlike toename in die
droe massa van die blomkop. Die vermoede bestaan dat beskaduwing tydens hierdie
fase, saam met die toename in die ontwikkelende blomkop se behoefte aan koolhidrate,
aanleiding gegee het tot 'n tydelike beperking in koolhidraatvoorraad wat die voorkoms
van blaarverswarting voor die oes tot gevolg gehad het.
Die bevinding dat glukose voordelig is vir die verlenging van beide die
bergingstyd en die vaasleeftyd van 'Sylvia' proteas het die navorsing gerig om ook
ondersoek in te stel na die gebruik daarvan vir ander Protea en Leucospermum
snyblomme. Merkbare veranderinge is gevind in die reaksie op glukosebyvoegings in
beide Protea en Leucospermum (speldekussings). Die opmerklike verskil in
sensitiwiteit vir glukosekonsentrasie in 'Pink Ice' proteas (fitotoksies by ~ 4%) en
'Susara' proteas (geen klaarblyklike toksisiteit), saam met 'n gebrek aan reaksie by
'Cardinal' proteas, 'n hibried van dieselfde ouers as 'Sylvia', dui aan dat verdere navorsing op individuele kultivars toegespits sal rnoet word. Glukosebyvoegings het
geen voordelige uitwerking op die vaasleeftyd van 'Scarlet Ribbon' en 'Tango'
speldekussings gehad nie, terwyl dit die vaasleeftyd van 'Cordi', 'Gold Dust', 'High
Gold' en 'Succession' speldekussingkultivars merkbaar verIeng het.
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Combate, prevenção e otimização das perdas comerciais de energia elétrica. / Combat, prevention and optimization of non technical losses of electric power distribution.Penin, Carlos Alexandre de Sousa 28 April 2008 (has links)
As perdas de energia elétrica devidas a furtos e fraudes, também chamadas de Perdas Não-Técnicas (PNT) ou Perdas Comerciais, têm sido matéria prioritária das empresas concessionárias de distribuição de energia elétrica, bem como dos órgãos reguladores, tanto pelo seu crescimento nos últimos anos quanto pelo seu impacto no sistema elétrico brasileiro. As formas de fraude são as mais variadas possíveis, o que gera enormes dificuldades para as concessionárias. Este trabalho tem como objetivo o estudo do problema das PNT utilizando-se de uma abordagem multidisciplinar, que analisa a experiência tanto de concessionárias no Brasil como no exterior. O trabalho discute as melhores práticas para mitigação das mesmas e propõe melhorias nos processos de combate e de prevenção, e nos procedimentos legais para recuperação de receitas, apoiados sobre uma cuidadosa contextualização regulatória. Chamase a atenção para a diversidade sócio-econômica nacional, compara-se com diversos exemplos internacionais, e propõe-se identificar os aspectos mais relevantes a serem considerados na regulação sobre o tema, discutindo procedimentos e metodologias para o equacionamento do montante de recursos a serem aplicados pelas companhias distribuidoras para a adequada redução dessas perdas de energia. Observa-se que grande parte das PNT tem origem em questões de cunho social. O Estado pode e deve estabelecer políticas para resolver tais questões, possibilitando a universalização do acesso e subsidiando o fornecimento de energia elétrica. Não fez parte dessa pesquisa discutir se estes instrumentos são suficientes ou devem ser aprimorados, mas sim analisar amplamente a questão das PNT com base nos condicionantes regulatórios atuais, que obrigam as concessionárias a reduzir estas perdas visando entre outros a modicidade tarifária dos consumidores regulares. / The electric power losses due to thefts and frauds, also called Non technical Losses (NTL), have been priority matter for concessionary companies of electric power distribution, as well as for government regulatory agencies, not only due to rapid growth over the past years but also due to its impact on Brazilian electrical system. There is a wide range of possible types and methods of frauds, causing enormous difficulties to licensed companies. The objective of this work is to study the problem of NTL using a wide approach, analyze the experience of dealerships in Brazil and abroad, discuss the best practices for mitigation of those losses and propose improvements in the combat and prevention processes, and the legal procedures for recovery of incomes, leaning on a careful regulatory context. This study draws attention to Brazil\'s socioeconomic diversity, comparing it to various international examples, and intends to identify the most relevant aspects that must be considered on the theme, discussing procedures and methodologies for the equation of the amount of resources to be applied by distributing companies to achieve the appropriate reduction of NTL. A large part of the commercial losses has its origin in issues of social stamp. The State owes and can establish policies to solve such issues, making possible the access to electric power supply for all consumers. It was not part of this research to discuss if these instruments are enough, but to analyze the issue of the commercial losses thoroughly based in the regulatory policies that push dealerships to reduce NTL objecting reasonable regular consumers\' tariff.
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Combate, prevenção e otimização das perdas comerciais de energia elétrica. / Combat, prevention and optimization of non technical losses of electric power distribution.Carlos Alexandre de Sousa Penin 28 April 2008 (has links)
As perdas de energia elétrica devidas a furtos e fraudes, também chamadas de Perdas Não-Técnicas (PNT) ou Perdas Comerciais, têm sido matéria prioritária das empresas concessionárias de distribuição de energia elétrica, bem como dos órgãos reguladores, tanto pelo seu crescimento nos últimos anos quanto pelo seu impacto no sistema elétrico brasileiro. As formas de fraude são as mais variadas possíveis, o que gera enormes dificuldades para as concessionárias. Este trabalho tem como objetivo o estudo do problema das PNT utilizando-se de uma abordagem multidisciplinar, que analisa a experiência tanto de concessionárias no Brasil como no exterior. O trabalho discute as melhores práticas para mitigação das mesmas e propõe melhorias nos processos de combate e de prevenção, e nos procedimentos legais para recuperação de receitas, apoiados sobre uma cuidadosa contextualização regulatória. Chamase a atenção para a diversidade sócio-econômica nacional, compara-se com diversos exemplos internacionais, e propõe-se identificar os aspectos mais relevantes a serem considerados na regulação sobre o tema, discutindo procedimentos e metodologias para o equacionamento do montante de recursos a serem aplicados pelas companhias distribuidoras para a adequada redução dessas perdas de energia. Observa-se que grande parte das PNT tem origem em questões de cunho social. O Estado pode e deve estabelecer políticas para resolver tais questões, possibilitando a universalização do acesso e subsidiando o fornecimento de energia elétrica. Não fez parte dessa pesquisa discutir se estes instrumentos são suficientes ou devem ser aprimorados, mas sim analisar amplamente a questão das PNT com base nos condicionantes regulatórios atuais, que obrigam as concessionárias a reduzir estas perdas visando entre outros a modicidade tarifária dos consumidores regulares. / The electric power losses due to thefts and frauds, also called Non technical Losses (NTL), have been priority matter for concessionary companies of electric power distribution, as well as for government regulatory agencies, not only due to rapid growth over the past years but also due to its impact on Brazilian electrical system. There is a wide range of possible types and methods of frauds, causing enormous difficulties to licensed companies. The objective of this work is to study the problem of NTL using a wide approach, analyze the experience of dealerships in Brazil and abroad, discuss the best practices for mitigation of those losses and propose improvements in the combat and prevention processes, and the legal procedures for recovery of incomes, leaning on a careful regulatory context. This study draws attention to Brazil\'s socioeconomic diversity, comparing it to various international examples, and intends to identify the most relevant aspects that must be considered on the theme, discussing procedures and methodologies for the equation of the amount of resources to be applied by distributing companies to achieve the appropriate reduction of NTL. A large part of the commercial losses has its origin in issues of social stamp. The State owes and can establish policies to solve such issues, making possible the access to electric power supply for all consumers. It was not part of this research to discuss if these instruments are enough, but to analyze the issue of the commercial losses thoroughly based in the regulatory policies that push dealerships to reduce NTL objecting reasonable regular consumers\' tariff.
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Quantifying non-uniformity in hot air treatment using tomato as a test material for postharvest quality and disease controlLu, Jianbo. January 2008 (has links)
The influence of uniformity of heat transfer with respect to the effect of heat treatment was investigated by correlating engineering parameters with the quantified heat treatment effects. Differences in treatment effect in terms of quality, anti-pathogen and chilling injury (CI) control properties among commodities was studied by exposing them to different target temperatures. Similar effects were also evaluated and quantified within an individual commodity by a custom-designed device. This device, whose design parameters were based on a heat transfer simulation, insured that one hemisphere of a tomato was exposed to air at 39°C and 0.24 m s-1; while the other hemisphere was exposed to air at a lower temperature with a velocity of0.24 m s-1 or 0.12 m s-1. / Single-temperature heat treatment was most effective in limiting pathogen development and varied according to the parameter measured: 38°C for hypersensitive response (HR), 36°C for tissue breakdown, 36°C, 38°C or 39°C for mycelium abundance, and 38°C or 39°C for lesion size. Bilateral differences in temperature across the fruit significantly affected disease control: decreasing temperature differences significantly improved the uniformity of disease control. / Some of the effects of heat treatment on tomato quality, such as color development and resistance to CI, appear to be localized. A significant difference in redness was identified between heated parts and unheated parts of tomato fruits immediately after treatment; and the differences persisted during storage. Differences in lightness and chroma were noted on day 4. Delay in ripening caused by heat treatment was confirmed through the higher TA and TSS values of heated tomatoes or heated portion of partially heated tomatoes. / The heated parts of tomatoes showed a stronger resistance to chilling injury. The effective temperature control range for CI was wide, but temperatures higher than 39.5°C for 23 h hot air treatment could lead to adverse effects. / Differences in physiological effects between hemispheres in two chambers was reduced by directly decreasing the temperature difference between upper and lower chambers or relatively increasing the heating air flow rate, highlighting the importance of improving the uniformity of air flow around each individual treated fruit.
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Evaluation of hot water and hot air heat shock treatments on South African avocados to minimise the occurrence of chilling injuryKritzinger, Madeleine 12 1900 (has links)
Thesis (MSc Food Sc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The South African avocado fruit industry is export driven and the successful
storage of fruits for extended periods is, therefore, essential. It was recorded
that 7.7 million cartons were exported during the 1995 season. The shipping
of the avocados takes approximately 15 days and the fruits are being stored
at low temperatures to minimise the possibility of fruits softening.
Unfortunately low temperature storage results in chilling injury. A possible
method to increase avocado resistance to chilling injury is to administer a heat
shock treatment. In this way the fruits are protected from chilling injury by
inducing the formation of so-called heat-shock proteins which render the cell
membranes more resistant to chilling injury.
The objective of this study was to evaluate different heat shock
treatment protocols as a method of preventing or minimising chilling injury and
to extend the shelf-life of avocado fruits while exporting at the lowest possible
temperature. Examining the effect of different temperatures and exposure
times on the quality of the different avocado cultivars pursued this. The
exterior chilling injury on each fruit was quantified and the firmness and
internal quality parameters evaluated.
A total of 32 Experimental Studies were conducted. The results
showed that the Hot Water Heat shock Treatment (HWHST) worked
effectively for the South African 'Fuerte' cultivar between 40° and 42°C for
exposure times of between 20 and 30 min. The 'Edranol' cultivar also showed
promising results between 40° and 42°C for exposure time of between 8 and
22 min. The HWHST was not effective on the South African 'Hass' cultivar.
The 'Ryan' cultivar with its thick skin made this cultivar less susceptible to
chilling injury and therefore HWHST would be unnecessary. The 'Pinkerton'
cultivar had a lot of factors that influenced the results. Therefore, more
research needed to be done on the 'Pinkerton' cultivar, before any
conclusions could be obtained from this cultivar, although it showed potential.
Hot air treatment worked fairly well, but unfortunately the long exposure time
needed made this treatment unpractical. Throughout the whole study the
importance of maturity surfaced as a major role in all the aspects of post
harvest quality. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse avokado vrugtebedryf is hoofsaaklik gerig op die
uitvoermark en daarom is dit belangrik dat die vrugte vir 'n bepaalde tyd
suksesvolopgeberg kan word. Die sensus opname gedurende die 1995
seisoen het getoon dat 7.7 miljoen bokse avokados uitgevoer is. Die
avokados word vir ongeveer 15 dae per boot vervoer, wat kan lei tot vrugte
wat sag word. Om dit te verhoed, word die vrugte by lae temperature
opgeberg. Ongelukkig veroorsaak lae opbergingstemperature koueskade. 'n
Moontlike metode om avokados te beskerm teen lae temperature en
koueskade te verminder, is om 'n hitteskok behandeling toe te pas. Op
hierdie manier word die vrugte beskerm teen koueskade deur die vorming van
sogenaamde hitteskok proteïene wat die selwande meer bestand maak teen
koueskade.
Die doel van hierdie studie was om die verskillende hitteskok
behandelings protokols te evalueer as 'n metode van beskerming of
vermindering van koueskade en om sodoende die rakleeftyd van avocados te
verleng as die vrugte by lae temperature uitgevoer word. Eksperimente is
uitgevoer om die effek van verskillende temperature en blootstellingstye op
die kwaliteit van die verskillende avokado kultivars te bepaal. Die koueskade
op die oppervlakte van elke vrug is bepaal en die fermheid en interne kwaliteit
parameters is geëvalueer.
In totaal is daar altesaam 32 Eksperimentele Studies gedoen. Die
resultate het gewys dat die Warm Water Hitteskok Behandeling (WWHB)
effektief was op die Suid-Afrikaanse 'Fuerte' kultivar by temperature tussen
40° en 42°C en by blootstellingstye van tussen 20 en 30 min. Belowende
resultate is ook met die 'Edranol' kultivar by temperature tussen 40° en 42°C
met blootstellingtye van tussen 8 en 22 min behaal. Die WWHB was
oneffektief vir die Suid-Afrikaanse 'Hass' kultivar. Die 'Ryan' kultivar se dik
skil het hierdie kultivar minder vatbaar gemaak vir koueskade en daarom was
'n WWHB onnodig gewees. By die 'Pinkerton' kultivar kon daar nog nie 'n
gevolgtrekking gemaak word nie, aangesien daar nog baie faktore is wat
ondersoek moet word, alhoewel die kultivar baie potentiaal getoon het. Warm
lug behandeling het potensiaal gehad, maar die lang blootstellingstye het hierdie behandeling onprakties gemaak. Gedurende die hele studie is daar
klem gelê op die rypheisgraad van die vrugte wat na vore gekom het as 'n
belangrike faktor wat 'n hoofrol speel in al die aspekte van die na-oes
kwaliteit.
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