Thesis (Ph. D.)--Dept. of Organic Chemistry, University of Adelaide, 1983. / 8 leaves of plates in pocket. Includes bibliographical references (leaves 148-154).

'Marion' and 'Thornless Evergreen' blackberry volatiles were analyzed by capillary gas chromatography-flame ionization detection (GC-FED) and GC-mass spectrometry (GC-MS). Based on total percentage of FID area 'Thornless Evergreen' contains significantly more alcohols, hydrocarbons, and phenols than the 'Marion'; 'Marion' contains more acids and esters. Both cultivars contained comparable amounts of aldehydes and ketones; alcohols were most abundant. The six most abundant volatiles in 'Marion' were ethanol, acetic acid, hexanoic acid, ethyl acetate, linalool, and 2-heptanol; they totaled 52% of total peak area. In 'Thornless Evergreen' the six most abundant volatiles were 2-heptanol, ethanol, 2,3-butanediol, hexanol, α-pinene, and ethyl acetate; they totaled 43% of total peak area. 'Marion' and 'Thornless Evergreen' blackberry aromas were compared using a pair of extraction and gas chromatography-olfactometry-mass spectrometry (GC-O-MS) methods. One method is based on purge-and-trap (P&T, dynamic headspace) extraction and aroma intensity rating by detection frequency (DetF) and a numeric scale, and the other based on solvent assisted flavor extraction (SAFE) and aroma threshold dilution analysis (AEDA). The parallel use of P&T-DetF GC-0 and SAFE-AEDA provided more representative blackberry volatile compositional data than either alone. Eighty-four compounds were identified; seventy-seven were in 'Marion', and sixty-eight in 'Thornless Evergreen'. Thirty-seven have not been previously reported in blackberry. Fourteen volatiles out of eighty-four were described with aroma descriptors specific to bramble fruit (berry, blackberry, bramble, raspberry); no single compound was unanimously described as "characteristically blackberry". Fresh 'Marion' blackberry aroma has been described as floral, fruity, sweet, caramel-fruity, and woody, while fresh 'Thornless Evergreen' aroma is spicy, green, herbaceous, fruity, and sweet. Except for esters, the cultivars contain comparable numbers of acids, alcohols, aldehydes, furanones, hydrocarbons, ketones, phenolics, sulfur, and Theaspirane compounds. Research data implies some portion of the more floral, fruity, and sweet aroma of the 'Marion' blackberry may be the result of additional esters not shared with the 'Thornless Evergreen' blackberry, yet both cultivars apparently contain five furanones, which are powerful sources of sweet, fruity, and spicy aromas. Aroma reconstitution studies will be the key to resolving the significant aroma profile differences between 'Marion' and 'Thornless Evergreen' blackberries, as characteristic blackberry aroma is apparently a complex formulation of volatiles. / Graduation date: 2004

8 leaves of plates in pocket / Bibliography: leaves 148-154 / 154 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Dept. of Organic Chemistry, University of Adelaide, 1983

Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2007. / Regal Seedless is a white, seedless grape which has the potential to become a profitable cultivar for the table grape producer since it has the advantages of early season harvesting and inherently large berries. There is, however, a downside to this cultivar, namely the seasonal occurrence of an unacceptable, astringent taste. This negative taste affects the demand by local and international markets. The astringency perception is due to the presence of phenolic compounds. It is well known that the phenolic composition and concentration change during the ripening of the grape. Different postharvest treatments are applied to fresh fruit like persimmons to remove astringency. These treatments include the use of carbon dioxide, nitrogen and ethanol. The aim of this study was to determine the optimum maturity level for Regal Seedless where the phenolic concentration is the lowest and the astringent taste acceptable. The use of postharvest treatments to manipulate the taste and the phenolic content, were also investigated. The effect on other quality parameters like total soluble solids (TSS), pH and total titratable acidity (TTA) were also evaluated.

Thesis (MScAgric)--Stellenbosch University, 1992. / One microfiche copy / ENGLISH ABSTRACT: The possibility of harvesting grapes at an earlier stage of maturity, based on differences in glucose and fructose concentration which influence the sweetness of grapes, was investigated. Although differences between cultivars were found the extent was not such that a specific cultivar could be selected in order to harvest at a lower sugar concentration, but with the same sweetness. Certain characteristics of table and wine grape cultivars with respect to anatomical composition and skin penetration resistance (SPR) were also investigated in order to ascertain the extent to which grapes would resist external damage, and to what extent turgor and skin thickness contributed to SPR. Daily variances in SPR confirm that not only skin strength, but also the turgor of the grape berry contributed to SPR. Skin penetration resistance seems to be a good criterion of the extent to which cultivars would resist external damage, because it is based on the toughness of the skin and the turgor of the berry. / AFRIKAANSE OPSOMMING: Die moontlikheid van vroeer oes op grond van verskille in die glukose- en fruktosekonsentrasie wat 'n invloed op die soetheid van druiwe mag he, is ondersoek. Daar is gevind dat die verskille wat tussen cultivars voorkom nie van so 'n grootte-orde is dat 'n spesifieke cultivar geselekteer kan word ten einde by 'n laer totale suiker, maar by dieselfde soetheidsgraad, te kan oes nie. Verder is sekere eienskappe van tafel- en wyndruifcultivars t.o.v. anatomiese samestelling en doppenetrasieweerstand (DP\V) ondersoek om die moontlike weerstand teen eksterne beserings en die mate waartoe turgor en dopdikte 'n invloed daarop mag uitoefen, _vas te stel. Daaglikse variasie in DPW het bevestig dat die DPW nie alleen afhanklik is van dopsterkte nie, maar ook van die turgor van die korrel. Doppenetrasieweerstand blyk 'n goeie maatstaf te wees vir die mate waartoe cultivars weerstand hied teen sekere eksterne beserings omdat dit gebaseer is op dopsterkte en turgor van die korrel.

The purpose of the experiment was to investigate the effect of fruit flavor compounds on biogas production from fruit wastes. The flavor compounds from different fruits were selected and synthetic medium was used throughout the experiment. The experiment was carried out both in batch and continuous process using thermophilic inoculums obtained from Söbacken waste management plant. The inhibitors were added at three different concentrations 0.05g/L, 0.5g/L and 5g/L respectively and were carried out in triplicates for batch cultivation.The result from batch cultivation showed that hexanal, (E)-2-hexanal, myrcene and octanol showed inhibitory activity. Hexanal, (E)-2-hexanal, myrcene, and octanol decreased biogas production by factor of 316.8%, 434.22%, 329.68% and 433.61% at concentration of 5g/L. Continuous experiment was carried out on Automatic Methane Potential Test System AMPTS II. Eight reactors, each with inhibitor compounds were used with a retention time of 30 days and an organic loading rate of 3g VS/day. The inhibitor concentration was increased from 0.5g/L to 5g/L and for some compounds up to 10g/L. During cultivation, several factors were measured periodically such as pH, total biogas production, biogas composition, FOS/TAC and VFA.The inhibitory effect was clearly shown at concentration higher than 0.5g/L. Addition of 5g/L hexanal, nonanal, (E)-2-hexanal, α-pinene , car-3-ene, myrcene and octanol resulted in reduction of biogas production by 81.2%, 4.67%, 50.74%, 7.06%, 24.01%, 31.84% and 52.85% respectively. When compared to batch process, continuous process required higher concentration of flavor compounds to reduce biogas production. This might be due to adaptation of cells towards toxic compounds during continuous process. / Program: Master of Science with a major in Resource Recovery-Industrial Biotechnology