ALBERT

Description: This study evaluates the efficacy of Improved Forest Management for Sustainable Livelihoods Program in communities adjacent to Mua-Livulezi Forest Reserve, Malawi. The program is specifically aimed at alleviating poverty and enhance rural livelihoods through promoting greater community involvement in forest management while providing access and associated benefits. The study therefore evaluated the effect of the program on community organisation, forest access, forest use, product availability and commercialisation of forest products. The results show that despite the program putting in place strategies for the people to access different products for different uses; forest use is restricted mainly to subsistence use rather than cash income. The main forest product collected by the people for livelihood was firewood, mainly for cooking and heating. This is an indication that forests are an important natural capital for subsistence rather than cash income. Gender, location of the village, and distance to the nearest forest area were significant predictors of households’ forest use. Introduction of the co-management program has not brought out the expected outcomes in areas of community organization, forest access, forest product availability and commercialisation of forest products. A multi-institutional approach is recommended to draw upon diverse talents and experiences from individual institutions both government and non-governmental in order to achieve meaningful social change.

Description: Rhizosphere carbon sequestration plays a crucial role in soil carbon dynamics. Little information is available on the dynamics of rhizosphere soil labile organic carbon fractions compared with bulk soil at different citrus stand age. Two replicate sites of three stand ages (10-, 20-, and 30-year) of citrus in the Three Gorges Reservoir area of China were studied. The results showed that rhizosphere soil organic carbon has an increases of 18.76 % under 20-year stand and 11.09 % under 30-year stand compared with bulk soil (P 〈 0.05), respectively. The dissolved organic C of rhizosphere soil was 31.32, 19.57 and 31.81 % higher compared with bulk soil under 10-, 20- to 30-year stands (P 〈 0.05), respectively, whereas readily oxidizable organic C (ROC) was 50.47, 70, and 64.54 % higher (P 〈 0.05). Microbial biomass (MBC) and water-soluble carbohydrate (WSCh) had no significant difference between rhizosphere and bulk soils in the 10- and 20-year stands, whereas a 9.88 % lower for MBC and a 36.47 % higher for WSCh in rhizosphere soil compared with bulk soil under 30-year stand were found (P 〈 0.05). Rhizosphere soil respiration showed a significantly negative relationship with ROC (r = 0.51, P 〈 0.05), WSCh (r = 0.60, P 〈 0.01) and MBC (r = 0.68, P 〈 0.01). The effect of the citrus rhizosphere on measured soil labile organic carbon fractions differed for each citrus stand age.

Description: Esterification of fatty acids with glycerol is characterized by negligible solubility of the two liquid phases. The reactions to mono-, di- and triglycerides taking place in the fatty acid phase, are limited by chemical equilibrium. The scope of this study is to investigate in a tubular reactor the conversion of a homogeneous mixture of oleic acid and glycerol in tert -butanol. The liquid composition in this study was 1 mol of oleic acid, 6 mol of glycerol and 14 mol of tert -butanol. Experiments were conducted in a tubular reactor at 35 atm over a temperature range of 200–240 °C and residence times of 0.7–17.6 h to determine the kinetics and the chemical equilibrium. The selectivity to monoolein was 〉95 mol %. A reversible second order reaction fits the data well.

Description: Pyrus communis ‘Rocha’ is an economically important crop very susceptible to the pathogenic fungus Stemphylium vesicarium , the causal agent of brown spot disease. Knowledge on the complexity of mechanisms responsible for resistance to S. vesicarium infection is necessary for definition of strategies to improve defence responses in susceptible cultivars. To investigate the molecular mechanisms behind Pyrus communis defence responses to S . vesicarium , a 6624 (3312 × 2) cDNA microarray was constructed to identify genes differentially expressed between a resistant/tolerant cultivar (‘Ercolini’) and a susceptible cultivar (‘Rocha’). Both cultivars were compared to evaluate their genetic background differences prior to inoculation (T0h) and transcriptional changes along a time course infection with S. vesicarium (T6h and T24h). Two cDNA libraries, from ‘Rocha’ and ‘Ercolini’ pear cultivars, spotted in the microarray resulted on 146 differential expressed genes. Transcriptome analysis revealed several transcripts related to stress and defence, namely peroxidases, 3-dehydroquinate dehydratase/shikimate 5-dehydrogenase, thiazole biosynthetic enzyme, serpins, cytochromes P450, 2-methyl-6-phytylbenzoquinone methyltransferase, 6-phosphogluconate dehydrogenase, polyneuridine-aldehyde esterase precursor, lipoxygenases and PR proteins. The results suggest that resistance/tolerance of ‘Ercolini’ cultivar may result from the rapid activation of defence mechanisms while in ‘Rocha’ cultivar the defence mechanisms may be activated too late for inducing an efficient response to infection by S. vesicarium . Cell wall strengthening and biosynthesis of antifungal compounds may constitute efficient physical and chemical barriers to S. vesicarium infection and priming emerges as a putative mechanism of resistance/tolerance. The evidence gathered combined with knowledge on host/endophyte signalling in mycorrhiza leads us to suggest priming as a measure to brown spot disease control in ‘Rocha’ pear cultivar through symbiosis with mycorrhizal fungi in order to anticipate and induce a more efficient activation of defence mechanisms. Also the thiazole biosynthetic enzyme and the serpins appears as potential candidates for the development of molecular markers for resistance to infection.

Description: Commercially available refined vegetable oils were investigated as calibration standards for the filtration device and protocol specified by ASTM D7501 for conducting the biodiesel cold soak filtration test. Filtration time was determined to be a function of the amount of vacuum applied during filtration, with an 8 % change in the filtration time of soybean oil occurring across the vacuum range specified by ASTM D7501. At a constant vacuum of 57 cm Hg the mean filtration time of 150 mL of soybean oil was independent of operator, device, and oil lot number. Mean filtration time was also largely independent of brand: the average of the mean filtration times of replicate samples of seven brands of soybean oil was 396 s with a minimum significant difference (MSD) of 28 s, and the filtration times of seven of eight brands of soybean oil tested fell within this MSD. Refined edible-grade corn, canola, peanut, safflower and sunflower oils gave reliable filtration times and would be suitable standards. Each oil exhibited a characteristic filtration time, all greater than that for soy oil. Filtration times were an approximately linear function of kinematic viscosities, as predicted by Darcy’s Law. Edible vegetable oils can serve as reliable, affordable, consistent and generally available materials for confirming the operability of the filtration device used in the biodiesel cold soak filtration test.

Description: Agroforestry systems (AFS) play a major role in the sequestration of carbon (C). The objectives of this study were to quantify the organic C stocks in the above- and below-ground tree biomass and in the soil in a cattle-farming system with live fences (CFSLF) of Gliricidia sepium and to compare the levels with those of a cattle-farming system based on a grass monoculture (CFSGM). The methodology included a forest inventory in nine randomly assigned plots and the destructive sampling of G. sepium 32 trees, measuring for each tree the diameter at breast height (DBH), stem height, total tree height, branch weight, leaf weight and coarse root weight. In addition, we measured grass biomass, collected litterfall and collected soil samples at depths of 0–10, 10–20 and 20–30 cm in the plots. A logarithmic model was developed to quantify the above- and below-ground tree biomass. The soil organic matter was determined by the dry combustion method. The total carbon stored in the CFSLF was 119.82 Mg C ha −1 , with the G. sepium trees contributing 5.7 % of the total C (6.48 Mg C ha −1 ). The CFSGM stored 113.34 Mg C ha −1 . The grass biomass stored 15.32 Mg C ha −1  year −1 in the CFSGM and 15.68 Mg C ha −1  year −1 in the CFSLF, and the litterfall in the CFSLF stored 0.205 Mg C ha −1  year −1 . Despite the modest contribution of G. sepium trees to the C storage, the total carbon accumulated in the CFSLF and CFSGM was similar.

Description: Uniform suspension of particulates (salt or spices) in oil-based marinades requires a gel behavior of the matrix. This can be achieved by adding a solid fat to the liquid oil. Besides rheology, appearance and thermal stability are important for the utilization as marinades. The influence of solid fat concentration ( c fat  = 2.5–5.5 wt%) and average cooling speed (1.4, 2.6, and 4.7 °C/min) on the functional properties of oil-fat gels from palm fat and canola oil was investigated. Oil-fat mixtures showed complex physiochemical behavior depending on the solid fat concentration and cooling rate. All samples had a shear-thinning behavior. Yield stresses and apparent viscosities increased at a constant cooling rate with increasing solid fat concentration. Frequency dependence of storage and loss modulus showed a transition from a viscous solution to a weak gel at c fat 〉 3.5 wt%. Samples at increasing cooling rates transitioned to weak gels at lower fat concentration (2.5 wt%). Mixtures became turbid and increasingly whiter as both solid fat concentration and cooling rates increased, which was explained by increased light-scattering by fat crystal aggregates. Results show the critical importance of proper formulation and preparation conditions on the functionality of oil-based marinades.

Description: Natural antioxidants to inhibit oxidation in edible oils are in high demand. Grape pomace is an abundant, inexpensive source of polyphenolic antioxidants, which are responsible for numerous health benefits. We examined pomace from eight varieties of Midwestern hybrid grapes for phenolic content and antioxidant activity. Ethanolic extracts produced from the pomace of each grape variety were added to two model systems, bulk soybean oil and oil-in-water emulsions, to determine antioxidant activity. Oxidation was monitored in each model system at a temperature appropriate to that particular system. While the extracts had relatively little effect in bulk oil, we observed dose-dependent antioxidant effects of some extracts in oil-in-water emulsions. Oxidation in bulk oils was assessed via total polar compounds and polymerized triacylglycerols. Oxidation in emulsions was assessed by peroxide value, headspace oxygen measurements, gas chromatography of headspace volatiles, and fatty acid analysis. Pomace extracts derived from red grapes generally outperformed those from white grapes, with the Marechal Foch variety showing high antioxidant activity at intermediate concentrations. At higher concentrations, Marechal Foch, Corot Noir, Frontenac, and Norton extracts showed promising antioxidant activity. This is the first report on antioxidant activity in an oil and emulsion setting for many of these grape varieties.

Description: There is a need to verify the quality of organically produced olive oils and to compare them to conventional ones. The objective of this study was to assess possible differences in nutritional quality between agronomic practices in Picual and Hojiblanca olive oil varieties at different stages of olive ripeness. The results showed that organic versus conventional cultivation did not consistently affect acidity, peroxide index or spectrophotometric constants of the virgin olive oils considered in this study. On the contrary, phenol content, oxidative stability, tocopherol content and fatty acid composition were affected by the agronomical practices. Principal component analysis indicated that linolenic acid and β-tocopherol were mainly responsible for discriminating Hojiblanca organic oils, whereas total phenols, palmitoleic acid and α-tocopherol were the major contributors to differentiating Picual conventional oils. Lignoceric and stearic acids were related to oils from unripe and ripe olive fruits, respectively. Long-term experiments are required to confirm these results.

Description: As part of a broader pattern of recovery after decline called forest transition, tree cover and carbon stocks have increased through agroforestry systems in many parts of Indonesia. The associated tree diversity transition implies that only the most useful parts of local tree flora are promoted. Swampland jelutong, Dyera polyphylla , has been domesticated in peat areas Jambi province, Indonesia. We discuss jelutong domestication in two coastal districts, referring to seven steps in a gradual change from products collected from communal natural forests to specific genotypes managed on private farms. Domestication of D. polyphylla in Jambi was in the initial stages three decades ago, when jelutong latex was directly tapped from the trees in its natural habitat of peat swamp forests. Tapping jelutong latex stopped in 2005 following the national regulation taxing forest products. Some farmers then started jelutong cultivation, motivated by the profitability of trading jelutong latex in the past. Our on-farm study showed that jelutong can be planted in various mixed agroforestry systems, with rubber, coffee or oil palm as dominants. Planted jelutong with good farm management showed diameter growth rates of 1.3 to 1.9 cm year −1 . On-farm trials showed that dolomite as soil ameliorant did not affect diameter growth, but had some effect on height. Jelutong planted between young oil palm had the best performance, while jelutong that was underplanted in mature rubber gardens grew slowly. Slow market revival currently constrains further tree domestication of jelutong.