Determinants of Choice of Marketing Outlets for African Indigenous Vegetables among the Agro-Pastoral Maasai of Narok and Kajiado Counties of Kenya

The Maasai of Narok and Kajiado counties have started embracing agro-pastoralism as a livelihood diversification strategy. Among the crop enterprises they have incorporated are African Indigenous Vegetables (AIVs) in a bid to take advantage of their resilience to the changing environment. Literature on market outlet choices has been thin, especially in developing countries where significant frictions make this question most salient. It is prudent to note that none of past studies identified factors affecting vegetable market outlet choices in Narok and Kajiado despite the high potential of vegetable production and marketing. However, for AIVs to be beneficial, it requires efficient marketing. An AIVs marketing analysis study was conducted in Narok and Kajiado counties to established the factors influencing the choice of AIVs marketing outlets among the agro-pastoral Maasai. Data was collected from 200 respondents using structured questionnaires. Purposive sampling method was used to select the sub counties and locations while a list from the extension offices was obtained and systematic sampling technique was used to select the households for the data collection. A multinomial logistic regression model was used to establish the factors influencing the choice of marketing outlets of AIVs. The results of the logistic regression model revealed that the choice of marketing outlet of the sampled agro-pastoral Maasai is influenced by quantity of AIVs sold, distance to the agricultural market, sex of the household, education level, household size, levels of value addition, farming experience in agro-pastoralism, off-farm income and marketing costs. In view of the research findings, it is imperative to enhance AIVs marketing in the studied areas to contribute to improved livelihoods among the agro-pastoral Maasai communities. Keywords: Agro-pastoralism, marketing outlets, choice of marketing outlets, livelihood

Direct analysis of plant materials using ambient ionization mass spectrometry

Ambient ionization mass spectrometry has revolutionized the area of mass spectrometric analysis by allowing the analysis of organic and inorganic compounds in their native environment without sample preparation. Eliminating sample preparation has consequently reduced analysis time by several orders of magnitude compared to traditional mass spectrometry techniques such as those involving liquid and gas chromatography. This has been true especially in the analysis of plant materials, where extensive extraction and purification steps are typically required prior to mass analysis. Here we report on applications of different ambient ionization methods developed in our laboratory for direct analysis of biologically relevant compounds in plant materials. The first part of this thesis discusses the use of the low temperature plasma (LTP) probe for qualitative analysis of extra virgin olive oil. Compounds which could be used to determine the authenticity of extra virgin olive oil such as free fatty acids and phenolic compounds were detected without the need for organic solvents or extraction processes. The second part of the thesis explores the direct analysis of chlorophyll catabolites in senescent plant tissues using desorption ionization (DESI) mass spectrometry. Non-fluorescent chlorophyll catabolites (NCCs), which are the final products of chlorophyll degradation, were detected and their molecular structures confirmed using tandem mass spectrometry (MS/MS) and reactive-DESI experiments. A novel imprinting method for imaging the spatial distribution of plant metabolites is described as well. Lastly, the relatively new paper spray ionization method was applied for direct analysis of polar lipids in green microalgae. A multi-step experimental protocol was employed to successfully characterize four classes of lipids in microalgae without the need for sample preparation. A novel approach for determining the position of unsaturation in olefins using reactive-paper spray ionization is described. Ozone produced in situ using simple low temperature plasma was used as the reagent molecule to cleave double bonds in the ions being analyzed by mass spectrometry

Direct Plant Tissue Analysis and Imprint Imaging by Desorption Electrospray Ionization Mass Spectrometry

The ambient mass spectrometry technique, desorption electrospray ionization mass spectrometry (DESI-MS), is applied for the rapid identification and spatially resolved relative quantification of chlorophyll degradation products in complex senescent plant tissue matrixes. Polyfunctionalized nonfluorescent chlorophyll catabolites (NCCs), the “final” products of the chlorophyll degradation pathway, are detected directly from leaf tissues within seconds and structurally characterized by tandem mass spectrometry (MS/MS) and reactive-DESI experiments performed in situ. The sensitivity of DESI-MS analysis of these compounds from degreening leaves is enhanced by the introduction of an imprinting technique. Porous polytetrafluoroethylene (PTFE) is used as a substrate for imprinting the leaves, resulting in increased signal intensities compared with those obtained from direct leaf tissue analysis. This imprinting technique is used further to perform two-dimensional (2D) imaging mass spectrometry by DESI, producing well-resolved images of the spatial distribution of NCCs in senescent leaf tissues

Unambiguous regiochemical assignment of sulfoquinovosyl mono- and diacylglycerols in parsley and spinach leaves by liquid chromatography/electrospray ionization sequential mass spectrometry assisted by regioselective enzymatic hydrolysis

Rationale: Sulfoquinovosylmonoglycerides (SQMG) and sulfoquinovosyldiglycerides (SQDG) in the lipid extracts of parsley (Petroselinum crispum) and spinach (Spinacia oleracea) leaves were investigated. The aim of this work was to assess and establish the chemical characterization of fatty acyl chains in sulfolipids (SQMG and SQDG) and their regiochemistry. Methods: A key component of this approach is a combination of hydrolysis reactions catalyzed by Lecitase® Ultra, which is a sn1-regioselective hydrolase enzyme, and reversed-phase liquid chromatography with electrospray ionization and sequential mass spectrometry (RPLC/ESI-MS) by collision-induced dissociation (CID)-MSn (n = 2, 3). Results: The occurrence of SQMG bearing 16:0 or 18:3 acyl chains was established for the first time. A regiochemistry-dependent fragmentation pattern of SQMG was attained whereby the sulfoquinovosyl anion ([C6H11O8S]â\u88\u92 at m/z 243.0) provides a diagnostic product ion. Regioselective enzymatic treatment also provided a posteriori confirmation of a widely accepted fragmentation rule for SQDG. The sulfoquinovosyl anion was found to play a role also in the fragmentation pattern of SQDG, whose regiochemical assignment could be ultimately confirmed by MS3 experiments. Conclusions: The predominant sulfolipid in leaf extracts of raw parsley (Petroselinum crispum) and spinach (Spinacia oleracea) was identified as SQDG 18:3/16:0, along with SQMG 18:3/0:0 and SQMG 16:0/0:0. The present CID-MS-based method can be considered a successful approach to validate the regiochemical characterization of sulfolipids paving the way for their unambiguous characterization