Starch residue samples from two Australian sweet potato varieties (Beauregard and Northern Star) and two Indonesian sweet potato varieties (Bis192 and Bis183), and commercial sample of sweet potato starch residue, were studied for their pectins. Pectins were extracted using 0.1M HCl, 0.05M NaOH, 0.1M HCl/0.75%SHMP, and 0.05M NaOH/0.75% SHMP. Hydrolysis of residual starch in the cell wall of sweet potato using heat stable α-amylase and amyloglucosidase was employed prior to pectin extraction to eliminate starch contamination. Pectins were characterised for yield, moisture, ash, galacturonic acid content (GA), degree of esterification (DE), neutral sugars content and molecular weight (MW). Selected pectins were also characterised for their dispersion and gel properties. Pectin with the highest yield was compared to commercial low methoxyl pectin (GRINSTED??YF 450) for its application in milk pudding. The pectin characteristics are dependent on variety and extraction process; however, the extraction methods were dominant. Yields were between 7 and 30 % of the cell wall. Ash varied from 2.9 to 6.8%. NaOH/SHMP extraction gave higher yields and ash contents. Moisture was between 5.5 and 6.7. GA varied from 27 to 80% with the highest found in Bis192 extracted using NaOH/SHMP. DE varied between traceable and 57%. HCl extraction gave higher DE, while NaOH/SHMP caused demethylation. Neutral sugars varied from 10 to 25% where galactose was the predominant sugar, followed by arabinose, rhamnose, glucose and xylose. Pectin MW was very heterogeneous. HCl extraction gave higher MW than the others. Dispersion of sweet potato pectins displayed shear-thinning. Consistency coefficient (K) increased, while flow behaviour index (n) decreased with increasing pectin concentration. HCl-extracted pectins formed stiff sugar-gels at concentrations higher than 2%. The optimum Ca2+ concentration for NaOH/SHMP-extracted pectin gels was 20 mg/g pectin. Pectin with the highest yield and stiffness (Norther Star extracted using NaOH containing SHMP) was used for milk pudding preparation. This pudding had comparable texture to pudding prepared from commercial low methoxyl citrus pectin (GRINSTED??YF 450). Overall, this study demonstrated that pectin from sweet potato starch residue is mainly low methoxyl pectin with possible chemical structure of rhamnogalacturonan I (RGI) that has potential for food applications.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1958. / Includes bibliographical references (p. 62-88).

The Microwave-Assisted Process (MAP$ sp{ rm TM}$) is an enhanced extraction technology patented by Environment Canada. MAP uses microwaves to rapidly transfer target compounds from one phase to another by selectively heating the phase containing the target compounds. This thesis presents the results of research performed to determine whether the MAP technique can be further developed into a large-scale soil treatment process that overcomes the limitations of conventional remediation technologies. / The dielectric properties of several mixtures of acetone and hexane over a temperature range from 25$ sp circ$C to 50$ sp circ$C were measured. The dielectric constants of these mixtures were found not to vary significantly with temperature. / A study of microwave absorption by heterogeneous mixtures showed that adding a solid material to a low dielectric constant solvent resulted in energy being preferentially absorbed by the solid. / The results of laboratory extraction tests showed that the ability of the MAP technique to extract contaminants was affected by the organic matter content of soil, particularly in the presence of water. / Use of a closed-vessel system yielded a 60% to 175% increase in the extraction of PAHs from a low organic-content soil relative to that achieved in an open-vessel system. (Abstract shortened by UMI.)

A colorimetric method was developed to determine the quantity of total azadirachtin related limonoids (AZRL) in neem extracts. A mathematical model was also developed to aid in the multivariate calibration technique for the analysis of the spectra. With this model and the multivariate calibration technique, the colorimetric method can be used directly to analyse the purified neem seed kernel extracts and to eliminate interferences from other absorbing species. The AZRL and simple terpenoids (ST) content in the neem seed kernel, the seed shell, the leaf and the leaf stem was determined with conventional extraction method and the newly developed quantification technique. The results showed that the AZRL content in these parts of neem decreases in the order of seed kernel > leaf > seed shell > leaf stem. With the HPLC quantification technique, the content of azadirachtin in the neem seed kernel was determined, and the comparison of the azadirachtin content and the AZRL content suggested that azadirachtin accounts for around 58% of the total AZRL. Microwave-assisted extraction (MAE) of AZRL and ST from various parts of neem was also investigated. Various parameters affecting the extraction such as the power and the microwave irradiation time were studied. The comparison of the MAE with two conventional extraction methods, viz., room temperature extraction (RTE) and reflux temperature extraction (RFX) revealed that the property of sample matrix affected the special accelerating effect of the MAE. The study on the influence of solvents on the MAE showed that the solubility of the solvent to the target components and the ability of the solvent to absorb microwave energy played an important role in MAE.

Starch residue samples from two Australian sweet potato varieties (Beauregard and Northern Star) and two Indonesian sweet potato varieties (Bis192 and Bis183), and commercial sample of sweet potato starch residue, were studied for their pectins. Pectins were extracted using 0.1M HCl, 0.05M NaOH, 0.1M HCl/0.75%SHMP, and 0.05M NaOH/0.75% SHMP. Hydrolysis of residual starch in the cell wall of sweet potato using heat stable α-amylase and amyloglucosidase was employed prior to pectin extraction to eliminate starch contamination. Pectins were characterised for yield, moisture, ash, galacturonic acid content (GA), degree of esterification (DE), neutral sugars content and molecular weight (MW). Selected pectins were also characterised for their dispersion and gel properties. Pectin with the highest yield was compared to commercial low methoxyl pectin (GRINSTED??YF 450) for its application in milk pudding. The pectin characteristics are dependent on variety and extraction process; however, the extraction methods were dominant. Yields were between 7 and 30 % of the cell wall. Ash varied from 2.9 to 6.8%. NaOH/SHMP extraction gave higher yields and ash contents. Moisture was between 5.5 and 6.7. GA varied from 27 to 80% with the highest found in Bis192 extracted using NaOH/SHMP. DE varied between traceable and 57%. HCl extraction gave higher DE, while NaOH/SHMP caused demethylation. Neutral sugars varied from 10 to 25% where galactose was the predominant sugar, followed by arabinose, rhamnose, glucose and xylose. Pectin MW was very heterogeneous. HCl extraction gave higher MW than the others. Dispersion of sweet potato pectins displayed shear-thinning. Consistency coefficient (K) increased, while flow behaviour index (n) decreased with increasing pectin concentration. HCl-extracted pectins formed stiff sugar-gels at concentrations higher than 2%. The optimum Ca2+ concentration for NaOH/SHMP-extracted pectin gels was 20 mg/g pectin. Pectin with the highest yield and stiffness (Norther Star extracted using NaOH containing SHMP) was used for milk pudding preparation. This pudding had comparable texture to pudding prepared from commercial low methoxyl citrus pectin (GRINSTED??YF 450). Overall, this study demonstrated that pectin from sweet potato starch residue is mainly low methoxyl pectin with possible chemical structure of rhamnogalacturonan I (RGI) that has potential for food applications.

Thesis (M. Sc.)--Carleton University, 2005. / Includes bibliographical references (p. 85-91). Also available in electronic format on the Internet.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 151-159). Also available in electronic format on the Internet.

Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 71-74). Also available in electronic format on the Internet.