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You searched for subject:(isolatietechnieken). Showing records 1 – 2 of 2 total matches.

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1. Kiskini, Alexandra. Sugar beet leaves: from biorefinery to techno-functionality.

Degree: 2017, Wageningen University

Sugar beet leaves (SBL), which are a side stream of the sugar beets cultivation, are currently left unexploited after sugar beets have been harvested. The general aim of this thesis was to study the biorefinery of SBL, with a special focus on the isolation of proteins. To reach this aim the research was divided into three sub-aims: 1) to determine whether there is variability in the chemical composition of the leaves due to pre-harvest conditions (plant age), 2) to evaluate the variability of the techno-functionality of leaf soluble protein concentrate (LSPC) due to system conditions and 3) to extend current product and process synthesis approaches to enable the design of biorefining process. To address the first aim, SBL collected at different time points were used. Despite a small variation in the chemical composition of the leaves of different plant ages, a large effect of the plant age on the quality of LSPC was observed. In particular, LSPC from old plants was brown (indicative of polyphenol oxidase - PPO - activity), whereas LSPC from young plants was yellow. Based on these data, samples extracted with sodium disulfite (to inhibit PPO-mediated browning) were used for further experiments. The obtained LSPC consisted mainly of protein (69.3% w/w db (N∙5.23)) and carbohydrates (5.1% w/w db; half of which was charged carbohydrates). The main protein present in LSPC was Rubisco. The emulsion and foam properties of LSPC were studied as a function of protein concentration (Cp), pH and ionic strength (I). The minimal Cp of LSPC needed to form a stable emulsion (Ccr) was comparable to that of other widely used plant proteins, such as soy protein isolate. A critical ζ-potential (ζcr ~ 11 mV) was identified, below which flocculation occurs. At pH 8.0 and high I (0.5 M) the Ccr was higher than at low I (0.01 M), which relates to a higher protein adsorbed amount at the interface (Γmax). The foam ability (FA) of LSPC increased with Cp at all conditions tested. The FA was related to the soluble and not to the total Cp in the bulk. Interestingly, the minimal Cp; i.e.CcrFA needed to reach highest FA was constant as a function of pH. At high I (0.5 M) LSPC had higher FA than at low I (0.01 M), which was related to the faster adsorption of proteins at the interface. A minimum Cp was required to form stable foams. At pH 3.0 and 5.0 the foam stability of LSPC was higher than at pH 8.0. This was postulated to be due to formation of aggregates (between proteins or between proteins and charged carbohydrates). From these data it was shown that the techno-functional properties of LSPC could be linked to the molecular and interfacial properties of the dominant proteins in the concentrates. Thus, predictions for the techno-functional properties of impure systems, such as LSPC, can be made using only the known molecular properties of the dominant proteins and a small set of experiments. The knowledge acquired through the previous studies was used to adapt an existing methodology; namely the product-driven-process synthesis (PDPS)… Advisors/Committee Members: Wageningen University, H. Gruppen, P.A. Wierenga.

Subjects/Keywords: suikerbieten; suikerbietenloof; bioraffinage; bioproceskunde; eiwitten; isolatietechnieken; fysiologische leeftijd; Levensmiddelen- en bioproceskunde (algemeen); sugarbeet; sugarbeet tops; biorefinery; bioprocess engineering; proteins; isolation techniques; physiological age; Food and Bioprocess Engineering (General)

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Kiskini, A. (2017). Sugar beet leaves: from biorefinery to techno-functionality. (Doctoral Dissertation). Wageningen University. Retrieved from http://library.wur.nl/WebQuery/wurpubs/528399 ; urn:nbn:nl:ui:32-528399 ; urn:nbn:nl:ui:32-528399 ; http://library.wur.nl/WebQuery/wurpubs/528399

Chicago Manual of Style (16th Edition):

Kiskini, Alexandra. “Sugar beet leaves: from biorefinery to techno-functionality.” 2017. Doctoral Dissertation, Wageningen University. Accessed October 17, 2019. http://library.wur.nl/WebQuery/wurpubs/528399 ; urn:nbn:nl:ui:32-528399 ; urn:nbn:nl:ui:32-528399 ; http://library.wur.nl/WebQuery/wurpubs/528399.

MLA Handbook (7th Edition):

Kiskini, Alexandra. “Sugar beet leaves: from biorefinery to techno-functionality.” 2017. Web. 17 Oct 2019.

Vancouver:

Kiskini A. Sugar beet leaves: from biorefinery to techno-functionality. [Internet] [Doctoral dissertation]. Wageningen University; 2017. [cited 2019 Oct 17]. Available from: http://library.wur.nl/WebQuery/wurpubs/528399 ; urn:nbn:nl:ui:32-528399 ; urn:nbn:nl:ui:32-528399 ; http://library.wur.nl/WebQuery/wurpubs/528399.

Council of Science Editors:

Kiskini A. Sugar beet leaves: from biorefinery to techno-functionality. [Doctoral Dissertation]. Wageningen University; 2017. Available from: http://library.wur.nl/WebQuery/wurpubs/528399 ; urn:nbn:nl:ui:32-528399 ; urn:nbn:nl:ui:32-528399 ; http://library.wur.nl/WebQuery/wurpubs/528399

2. Holthoon, van, F.L. Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System.

Degree: 2004, NARCIS

Infochemicals play an important role in interactions between living organisms in aquatic environments. Although the presence of these chemical cues is confirmed in more and more systems, the chemical structures of the compounds involved remain predominantly elusive and the identification of these compounds is essential to advance the research on chemical communication. An overview of chemical cues involving Daphnia (either as producer or receiver) is given and the progress towards their isolation and structure elucidation is described (</span><span lang=EN-GB style='font-size:14.0pt;line-height:125%; mso-ansi-language:EN-GB'>Chapter 1</span><span lang=EN-GB style='mso-ansi-language: EN-GB'>). Most of the research so far has concentrated on the elucidation of kairomones produced by predators of Daphnia (especially Chaoborus and several species of fish). Less study has been devoted to the isolation of the infochemical exuded by Daphnia that causes colony formation in its prey Scenedesmus. One of the main aims of this study was the isolation and identification of this chemical cue. Colony formation in Scenedesmus only occurs when unicellular populations are exposed to either Daphnia or water that had contained Daphnia. It was concluded that the responsible cue had a chemical rather than a mechanical nature, since filtered Daphnia water also showed the colony formation activity. This colony formation was the basis for the development of a bioassay (</span><span lang=EN-GB style='font-size:14.0pt;line-height:125%; mso-ansi-language:EN-GB'>Chapter 2</span><span lang=EN-GB style='mso-ansi-language: EN-GB'>). A bioassay is a test that is used to measure biological activity (in this case colony formation) of chemical mixtures or biological parameters. Colonies are indicated by high values and single cells are indicated by low values. Unfortunately over time a gradual decline of the difference between negative and positive controls was observed and efforts were undertaken to determine the cause for this decline. Several conditions were investigated (such as time, temperature, algae strain, culture medium, location, incubator, Erlenmeyer size, bacterial growth and microevolution). Additionally some general properties of the kairomone (such as thermal decomposition, biodegradation and concentration) were tested. A correlation between any of the above mentioned factors and the gradual decline of the difference between negative and positive controls was not found. Given that the bioassay was performed under such highly variable and not strictly controlled circumstances, this particular bioassay seems to be rather robust. However this does not defer from the fact that the quality of the bioassay did decline over time. Until the variable is identified that is responsible for the observed decline in difference between positive and negative controls, more care should be taken to standardise as many variables as possible. Despite its drawbacks, a bioassay still remains the best option to guide isolations of bioactive compounds through… Advisors/Committee Members: Wageningen University, Aede de Groot, Teris van Beek, E. van Donk.

Subjects/Keywords: daphnia; predator prooi verhoudingen; waarschuwingsferomonen; isolatietechnieken; chemische structuur; fractionering; hplc; kernmagnetische resonantiespectroscopie; Organische chemie; daphnia; predator prey relationships; alarm pheromones; isolation techniques; chemical structure; fractionation; hplc; nuclear magnetic resonance spectroscopy; Organic Chemistry

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Holthoon, van, F. L. (2004). Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System. (Doctoral Dissertation). NARCIS. Retrieved from http://library.wur.nl/WebQuery/wurpubs/336498 ; urn:nbn:nl:ui:32-336498 ; urn:nbn:nl:ui:32-336498 ; http://library.wur.nl/WebQuery/wurpubs/336498

Chicago Manual of Style (16th Edition):

Holthoon, van, F L. “Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System.” 2004. Doctoral Dissertation, NARCIS. Accessed October 17, 2019. http://library.wur.nl/WebQuery/wurpubs/336498 ; urn:nbn:nl:ui:32-336498 ; urn:nbn:nl:ui:32-336498 ; http://library.wur.nl/WebQuery/wurpubs/336498.

MLA Handbook (7th Edition):

Holthoon, van, F L. “Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System.” 2004. Web. 17 Oct 2019.

Vancouver:

Holthoon, van FL. Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System. [Internet] [Doctoral dissertation]. NARCIS; 2004. [cited 2019 Oct 17]. Available from: http://library.wur.nl/WebQuery/wurpubs/336498 ; urn:nbn:nl:ui:32-336498 ; urn:nbn:nl:ui:32-336498 ; http://library.wur.nl/WebQuery/wurpubs/336498.

Council of Science Editors:

Holthoon, van FL. Isolation and Identification of Kairomone(s) in the Daphnia-Scenedesmus System. [Doctoral Dissertation]. NARCIS; 2004. Available from: http://library.wur.nl/WebQuery/wurpubs/336498 ; urn:nbn:nl:ui:32-336498 ; urn:nbn:nl:ui:32-336498 ; http://library.wur.nl/WebQuery/wurpubs/336498

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