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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Frutos de umbuzeiro (Spondias tuberosa Arruda) : características físico-químicas durante seu desenvolvimento e na pós-colheita /

Campos, Clarismar de Oliveira, 1950- January 2007 (has links)
Orientador: Giuseppina Pace Pereira Lima / Banca: João Domingos Rodrigues / Banca: Elizabeth Orika Ono / Banca: Lilia Willadino / Banca: Manuel Abilio de Queiróz / Resumo: Este trabalho foi conduzido em quatro etapas, visando acompanhar o desenvolvimento das características físico-químicas de frutos de umbuzeiro (Spondias tuberosa Arruda); estabelecer a curva de crescimento do fruto e aspectos pós-colheita dos frutos do umbuzeiro, objetivando estabelecer estratégias para melhor conservar os frutos, tendo em vista que o fruto desta fruteira, caracteriza-se como uma fruta exótica, já alcançando o mercado europeu. As plantas escolhidas, localizam-se na quadrícula 400 e 420 de Longitude (W. C) e 80 e 100 de Latitude Sul, sendo colhidos frutos de vinte plantas em cinco Unidades Geoambientais. O delineamento experimental utilizado foi o inteiramente casualizado e o arranjo, a depender da situação, fatorial aninhado (nested). Concluiu-se neste trabalho que os umbuzeiros presentes nas Unidades Geoambientais da Depressão Sertaneja, apresentam grande variabilidade fenotípica, manifestada pelo peso médio do fruto, peso médio da polpa, teor de vitamina C e acidez titulável. De acordo com a curva de crescimento do fruto, os estádios podem ser visualizados pelo peso do fruto e pela coloração da casca. O florescimento do umbuzeiro ocorre entre setembro e outubro, a fecundação das flores não ocorre todas de uma só vez, são fecundadas paulatinamente no decorrer de trinta dias, em média, fazendo com que a colheita se estenda entre vinte e trinta e cinco dias. A classificação proposta, dos estádios de desenvolvimento foi de 1FTV-F (fruto totalmente verde. Figa - caroço esbranquiçado, em formação), 2FTV-D (fruto totalmente verde. Devéz - caroço duro, ponto de umbuzeitona), 3FTV-In (fruto totalmente verde. Inchado - início da pigmentação), 4FPA-M-1 (fruto com predominância do amarelo - Maduro 1), 5FTA-M-2 (fruto totalmente amarelo - Maduro 2), 6FTA-P (fruto totalmente amarelo - Passado). O conteúdo de vitamina C no suco... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work was carried out in four stages in order to follow the development of the physical and chemical characteristics of umbu tree fruits (Spondias tuberosa Arruda) and to establish the fruit growth curve and aspects of postharvest of umbu tree fruits with the goal to establish strategies to improve conservation of umbu fruits since it is an exotic fruit reaching the European markets. The fruits were harvested from twenty plants randomly chosen in five Geoambiental unities located in quadrants 400 and 420 of longitude (W. C) and 80 and 100 of south latitude. The experimental design was completely randomized in a factorial (nested) arrangement when necessary. The conclusion was that the umbu trees present in the Geoambiental unities showed high variability expressed by average of fruit weight, fruit pulp, vitamin C contents and titrable acidity. According to the fruit growth curve the stage can be observed by fruit weight and coloration of rind. The bloom of umbu tree occurs between September and October, the fecundation of flowers do not develop at one time but instead gradually on average of thirty days and harvest occur between twenty and thirty five days. The proposal classification of umbu trees stages was the following: 1FTV-F (fruit totally green. Figa - seed white in formation), 2FTV-D (fruit totally green Devez - hard seed, ponto de umbuzeitona), 3 FTV -In (fruit totally green. Swelled - start of pigmentation, 4FPA - M - 1 (fruit predominantly yellow - ripe 1), 5 FTA -M - 2 (fruit totally yellow - ripe 2), 6FTA - P (fruit totally yellow - over-ripe). The vitamin C contents in umbu juice varied from 41, 9g in 100 ml in stage 1FTV - F (figa) to 8,5g in 100 ml in stage 5 FTA-M-2 (ripe 2). The titrable acidity, quantity of citric acid, varied from 4,5g in 100g of juice in stage 1FTV-F (figa) to 1,4g in 100g of juice in stage 5 FTA-M-2 (ripe 2). The soluble solids given... (Complete abstract click electronic access below) / Doutor
12

Postharvest physiology of fresh cut tomato slices.

Pangaribuan, D. H. Unknown Date (has links)
No description available.
13

Resistance to airflow and moisture loss of table grapes inside multi-scale packaging

Ngcobo, Mduduzi Elijah Khulekani 03 1900 (has links)
Thesis (PhD(Agric))--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Postharvest quality of fresh table grapes is usually preserved through cooling using cold air. However, cooling efficiencies are affected by the multi-scale packaging that is commercially used for handling grapes after harvest. There is usually spatial temperature variability of grapes that often results in undesirable quality variations during postharvest handling and marketing. This heterogeneity of grape berry temperature inside multi-packages is largely due to uneven cold airflow patterns that are caused by airflow resistance through multi-package components. The aims of this study were therefore to conduct an in-depth experimental investigation of the contribution of grape multi-packaging components to total airflow resistance, cooling rates and patterns of grapes inside the different commercially used multi-packages, and to assess the effects of these multi-packages on table grape postharvest quality attributes. A comprehensive study of moisture loss from grapes during postharvest storage and handling, as well as a preliminary investigation of the applicability of computational fluid dynamics (CFD) modeling in predicting the transport phenomena of heat and mass transfer of grapes during cooling and cold storage in multi-packages were included in this study. Total pressure drop through different table grapes packages were measured and the percentage contribution of each package component and the fruit bulk were determined. The liner films contributed significantly to total pressure drop for all the package combinations studied, ranging from 40.33±1.15% for micro-perforated liner film to 83.34±2.13 % for non-perforated liner film. The total pressure drop through the grape bulk (1.40±0.01 % to 9.41±1.23 %) was the least compared to the different packaging combinations with different levels of liner perforation. The cooling rates of grapes in the 4.5 kg multi-packaging were significantly (P<0.05) slower than that of grapes in 5 kg punnet multi-packaging, where the 4.5 kg box resulted in a seven-eighths cooling time of 30.30-46.14% and 12.69-25.00% more than that of open-top and clamshell punnet multi-packages, respectively. After 35 days in cold storage at -0.5°C, grape bunches in the 5 kg punnet box combination (open-top and clamshell) had weight loss of 2.01 – 3.12%, while the bunches in the 4.5 kg box combination had only 1.08% weight loss. During the investigation of the effect of different carton liners on the cooling rate and quality attributes of ‘Regal seedless’ table grapes in cold storage, the non-perforated liner films maintained relative humidity (RH) close to 100 %. This high humidity inside non-perforated liner films resulted in delayed loss of stem quality but significantly (P ≤ 0.05) increased the incidence of SO2 injury and berry drop during storage compared to perforated liners. The perforated liners improved fruit cooling rates but significantly (P ≤ 0.05) reduced RH. The low RH in perforated liners also resulted in an increase in stem dehydration and browning compared to non-perforated liners. The moisture loss rate from grapes packed in non-perforated liner films was significantly (P<0.05) lower compared to the moisture loss rate from grapes packed in perforated liner films (120 x 2 mm and 36 x 4 mm). The effective moisture diffusivity values for stem parts packed in non-perforated liner films were lower than the values obtained for stem parts stored without packaging liners, and varied from 5.06x10-14 to 1.05x10-13 m2s-1. The dehydration rate of stem parts was inversely proportional to the size (diameter) of the stem parts. Dehydration rate of stems exposed (without liners) to circulating cold air was significantly (P<0.05) higher than the dehydration rates of stems packed in non-perforated liner film. Empirical models were successfully applied to describe the dehydration kinetics of the different parts of the stem. The potential of cold storage humidification in reducing grape stem dehydration was investigated. Humidification delayed and reduced the rate of stem dehydration and browning; however, it increased SO2 injury incidence on table grape bunches and caused wetting of the packages. The flow phenomenon during cooling and handling of packed table grapes was also studied using a computational fluid dynamic (CFD) model and validated using experimental results. There was good agreement between measured and predicted results. The result demonstrated clearly the applicability of CFD models to determine optimum table grape packaging and cooling procedures. / AFRIKAANSE OPSOMMING: Naoes kwaliteit van vars tafeldruiwe word gewoonlik behou deur middel van verkoeling van die produk met koue lug. Ongelukkig word die effektiwiteit van dié verkoeling beïnvloed deur die multivlakverpakking wat kommersieel gebruik word vir die naoes hantering van druiwe. Daar is gewoonlik ruimtelike variasie in die temperatuur van die druiwe wat ongewenste variasie in die kwaliteit van die druiwe veroorsaak tydens naoes hantering en bemarking. Die heterogene druiwetemperature binne die multivlakverpakkings word grootliks veroorsaak deur onegalige lugvloeipatrone van die koue lug as gevolg van die weerstand wat die verskillende komponente van die multivlakverpakkings teen lugvloei bied. Die doel van hierdie studie was dus om ‘n indiepte eksperimentele ondersoek te doen om die bydrae van multivlakverpakking op totale lugvloeiweerstand, verkoelingstempo’s en –patrone van druiwe binne kommersieël gebruikte multivlakverpakkings te ondersoek, asook die effek van die multivalkverpakking op die naoes kwaliteit van druiwe te bepaal. ‘n Omvattende studie van vogverlies van druiwe tydens naoes opberging en hantering, asook ‘n voorlopige ondersoek na die bruikbaarheid van ‘n berekende vloei dinamika (BVD) model om die bewegingsfenomeen van hitte en massa oordrag van druiwe tydens verkoeling en koelopberging in multivlakverpakkings te voorspel, was ook by die studie ingesluit. Die totale drukverskil deur verskillende tafeldruif verpakkingssisteme is gemeet en die persentasie wat deur elke verpakkingskomponent en die vruglading bygedra is, is bereken. Van al die verpakkingskombinasies wat gemeet is, het die voeringfilms betekenisvol tot die totale drukverskil bygedra, en het gewissel van 40.33±1.15% vir die mikro geperforeerde voeringfilm tot 83.34±2.13 % vir die nie-geperforeerde voeringfilm. Die totale drukverskil oor die druiflading (1.40±0.01 % to 9.41±1.23 %) was die minste in vergelyking met die verskillende verpakkingskombinasies met die verskillende vlakke van voeringperforasies. Die verkoelingstempos van die druiwe in die 4.5 kg multiverpakking was betekenisvol (P<0.05) stadiger as vir die druiwe in die 5 kg handmandjie (‘punnet’) multiverpakking. Die 4.5 kg karton het ‘n seweagstes verkoelingstyd van 30.30-46.14% en 12.69-25.00% langer, respektiewelik, as oop-vertoon en toeslaan-‘punnet’ multiverpakkings gehad. Na 35 dae van koelopberging by -0.5°C het druiwetrosse in die 5 kg ‘punnet’-kartonkombinasies (oop-vertoon en toeslaan-’punnet’) ‘n massaverlies van 2.01 – 3.12% gehad, terwyl die trosse in die 4.5 kg kartonkombinasie slegs ‘n 1.08% massaverlies gehad het. In die ondersoek na die effek van verskillende kartonvoerings op die verkoelingstempo en kwaliteitseienskappe van ‘Regal seedless’ tafeldruiwe tydens koelopbering, het die nie-geperforeerde kartonvoerings ‘n relatiewe humiditeit (RH) van byna 100 % gehandhaaf. Hierdie hoë humiditeit in die nie-geperforeerde voeringfilms het ‘n verlies in stingelkwaliteit vertraag, maar het die voorkoms van SO2-skade en loskorrels betekenisvol (P < 0.05) verhoog in vergelyking met geperforeerde voerings. Die geperforeerde voerings het vrugverkoelingstempos verbeter, maar het die RH betekenisvol (P ≤ 0.05) verlaag. Die lae RH in die geperforeerde voerings het gelei tot ‘n verhoging in stingeluitdroging en –verbruining in vergelyking met die nie-geperforeerde voerings. Die vogverliestempo uit druiwe verpak in nie-geperforeerde voeringfilms was betekenisvol (P<0.05) stadiger in vergelyking met druiwe verpak in geperforeerde voeringfilms (120 x 2 mm and 36 x 4 mm). Die effektiewe vogdiffusiewaardes vir stingelgedeeltes verpak in nie-geperforeerde voeringfilms was stadiger as vir stingelgedeeltes wat verpak is sonder verpakkingsvoerings, en het gevarieer van 5.06x10-14 – 1.05x10-13 m2s-1. Die uitdrogingstempo van stingelgedeeltes was omgekeerd eweredig aan die grootte (deursnit) van die stingelgedeeltes. Die uitdrogingstempo van stingels wat blootgestel was (sonder voerings) aan sirkulerende koue lug was betekenisvol (P<0.05) hoër as die uitdrogingstempos van stingels wat verpak was in nie-geperforeerde voeringfilms. Empiriese modelle is gebruik om die uitdrogingskinetika van die verskillende stingelgedeeltes te beskryf. Die potensiaal van koelkamer humidifisering in die vermindering van die uitdroging van druifstingels is ondersoek. Humidifisering het stingeluitdroging vertraag en het die tempo van stingeluitdroging en -verbruining verminder, maar dit het die voorkoms van SO2-skade op die tafeldruiftrosse verhoog en het die verpakkings laat nat word. Die bewegingsfenomeen tydens verkoeling en hantering van verpakte tafeldruiwe is ook ondersoek deur gebruik te maak van ‘n BVD model en is bevestig met eksperimentele resultate. Daar was goeie ooreenstemming tussen gemete en voorspelde resultate. Die resultaat demonstreer duidelik die toepaslikheid van BVD-modelle om die optimum tafeldruifverpakkings- en verkoelingsprosedures te bepaal. / PPECB and Postharvest Innovation Programme (PHI-2) for their financial support
14

An investigation of vascular discolouration in potato tubers (Solanum tuberosum L.) treated with imazethapyr

Spackman, Victoria M. T. January 1998 (has links)
No description available.
15

Evaluation of Induced Cells of ​Rhodococcus Rhodochrous​ to Inhibit Fungi​

Saqib, Muzna 13 December 2016 (has links)
Rhodococcus rhodochrous is an aerobic, non- pathogenic ,gram-positive bacterium that is often used in industries as a biocatalyst.R. rhodochrous DAP 96253 is capable of exhibiting contact-independent inhibition of selected fungal pathogens.The use of R. rhodochrous as a potential biocontrol agent against plant and animal fungi was examined.The fungi tested were Botrytis cinerea,Pseudogymnoascus destructans,Aspergillus flavus, Fusarium oxysporum’Cigar Tip’ , Rhizopus stolonifer’D1’ ,and other species isolated from berries.Each species was studied to establish the effect of dose (g/cells) and time of exposure to R. rhodochrous.Antifungal inhibition tests were done with the use of dosing,agar diffusion, frozen fermentation paste and exposed slides.Inhibition was observed with B.cinerea,P.destructans,A.flavus and D1,and reduced sporulation was observed with Cigar Tip. The results varied amongst the type of tests used on each target species.
16

Boron nutrition of hass avocado (Persea Americana Mill.)

Smith, T. E. Unknown Date (has links)
No description available.
17

The effects of clumped log distribution on line intersect sampling

Tansey, Joshua January 2014 (has links)
Line intersect sampling (LIS) is a method used for quantifying post-harvest waste. It is often used by forest managers to quantify merchantable volume remaining on the cutover so that compensation may be exacted under stumpage contracts. The theory has been extensively studied and will produce an accurate measure of harvest waste given the basic theoretical assumptions that: all logs are cylindrical, occur horizontally, are randomly orientated and randomly distributed. When these assumptions are violated, the method is not biased, although precision decreases substantially. A computer simulation was completed to determine whether or not the LIS method is appropriate, given a clumped distribution of logs produced by processing at central sites in cutover before using a forwarder to extract to the landing. The software ArcGIS with the application ModelBuilder was used to produce the LIS Model for running LIS assessments. It was determined through simulation that the conventional LIS method is not appropriate given these harvesting methods, as a level of bias was found in sampling determining that the LIS method underestimated true volume. T-tests confirmed the significance of this bias. LIS volume estimates were not precise, with the range of estimates ranging from 0 m3/ha to double the true volume. An increase in sampling length by a third was found to increase precision by only a small amount. Therefore, it was determine that increased sampling is not worthwhile as the costs associated with it do not justify the small increase in precision.
18

Boron nutrition of hass avocado (Persea Americana Mill.)

Smith, T. E. Unknown Date (has links)
No description available.
19

Anatomy and Physiology of Floral Organ Abcission in Geraldton Waxflower (Chamelaucium Uncinatum Schauer)

Macnish, A. J. Unknown Date (has links)
No description available.
20

CaracterizaÃÃo de GenÃtipos de aceroleira por variÃveis agronÃmicas e de pÃs-colheita em diferentes estaÃÃes climÃticas / Characterization of acerola genotypes for agronomic traits and post-harvest in different seasons

AlÃssa Milena PaixÃo Bandeira 17 February 2012 (has links)
Apesar de vÃrios estudos jà desenvolvidos com a cultura da acerola, ainda existe um grande nÃmero de genÃtipos a ser caracterizados sob vÃrios aspectos, principalmente os genÃticos. Adicionalmente, alÃm dos fatores genÃticos, a composiÃÃo dos frutos da aceroleira pode ser afetada em funÃÃo das condiÃÃes ambientais durante seu desenvolvimento (estaÃÃo seca / Ãmida). Diante da demanda por novos clones a Embrapa AgroindÃstria Tropical desenvolveu, nos anos de 1996 a 2007, um programa de melhoramento genÃtico da aceroleira, lanÃando no ano de 2003 quatro clones recomendados para o Estado do CearÃ: BRS 235(Apodi), BRS 236 (Cereja), BRS 237 (Roxinha) e BRS 238 (Frutacor), originando atravÃs de seleÃÃo o Jardim de Sementes. Assim, o objetivo deste trabalho consistiu na caracterizaÃÃo dos genÃtipos de aceroleira do Jardim de Sementes por meio de variÃveis agronÃmicas e de pÃs-colheita e avaliaÃÃo da existÃncia de diversidade genÃtica desse material. O experimento foi instalado no campo Experimental de Pacajus (CE), sob delineamento inteiramente casualizado, avaliou-se 36 genÃtipos para variÃveis agronÃmicas (morfologia, fenologia e produÃÃo) e 25 genÃtipos para as variÃveis de pÃs-colheita (peso, firmeza, sÃlidos solÃveis, acidez titulÃvel, relaÃÃo SS/AT, pH da polpa, vitamina C, antocianina, flavonÃides, atividade antioxidante e polifenÃis), com trÃs repetiÃÃes e nas estaÃÃes seca de 2009 e Ãmida e seca de 2010, foi realizada anÃlise descritiva para as variÃveis agronÃmicas, na qual verificou-se que os genÃtipos apresentam altura e diÃmetro adequados para plantios comerciais. Observaram-se picos de floraÃÃo nos meses de abril, outubro e dezembro e cinco picos de frutificaÃÃo. Quanto à produtividade, destacaram-se os clones 9, 14, 28, 37 e 38. Foram realizadas anÃlises univariada e conjunta onde foram observadas mudanÃas nas variÃveis de pÃs-colheita durante as estaÃÃes com relaÃÃo a peso, sÃlidos solÃveis, acidez titulÃvel, vitamina C, antocianinas, atividade antioxidante e polifenÃis; entretanto, as mudanÃas na firmeza, pH e flavonÃides nÃo foram significativas. AtravÃs da anÃlise multivariada verificou-se a existÃncia de diversidade entre os materiais, destacando-se os clones 13 e 37. Utilizou-se do Ãndice de seleÃÃo de Mulamba e Mock para escolha dos materiais que apresentassem uma sÃrie de atributos favorÃveis quanto as caracterÃsticas de pÃs-colheita onde destacaram-se os clones 3, 13, 14, 27 e 38. / Although several studies have developed the culture of acerola, there is still a large number of genotypes to be characterized in many ways, mainly genetic. Additionally, from genetic factors, the composition of acerola fruit can be affected depending on environmental conditions during development (season dry/wet). Giver the demand for new clones to postharvest developed in the years 1996 to 2007, a breeding program of acerola, launching in 2003, four clones recommended for the state of CearÃ: BRS 235 (Apodi), BRS 236 (Cereja), BRS 237 (Roxinha) and BRS 238 (Frutacor), leading through the selection of garden seeds. The objective of this study was to characterize the genotypes of acerola garden seed through agronomic variables and post-harvest assessment of the existence of genetic diversity of this material. The experiment was installed in the field of experimental Pacajus (CE) under completely randomized design, 36 genotypes were evaluated for agronomc traits (morphology, phenology, and producyion) and 25 genotypes for post-harvest variables (weight, firmness, soluble solids, acidity, ratio ss/ta, pH of the pulp, vitamin C, anthocyanins, flavonoids, antioxidant activity and polyphenols) with three repetitions and the season dry of 2009 and wet and dry of 2010. Descriptive analysis was perfomed for agronomic traits in which it was found that the genotypes have height and diameter suitable for commercial plantation. Peaks were observed flowering in april, october and December and five fruiting peaks. As for productivity, the highlights were the clones 9, 14, 28, 37 and 38. We performed univariate and joint where we observed in variables during the post-harvest season with respect to weight, soluble solids, titratable acidity, vitamin C, anthocyanins, polyphenols and antioxidant activity, however, changes in texture, pH and flavonoids were significant. By multivariate analysis showed the existence of diversity among materials, especially clones 13 and 37. We used the selection index of Mulamba and Mock choice of materials to that presented a number of favorable attributes as the characteristics of post-harvest which highlights the clones 3, 13, 14, 27 and 38.

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