Impact of liberalization on efficiency and productivity of sugar industry in Kenya

Purpose – The data used in this study is for the period 1980-2000. Almost midway through this period (in 1992), the Kenyan government liberalized the sugar industry and the role of the market increased, while the government's role with respect to control of prices, imports and other aspects in the sector declined. This exposed the local sugar manufacturers to external competition from other sugar producers, especially from the COMESA region. This study aims to find whether there were any changes in efficiency of production between the two periods (pre and post-liberalization). Design/methodology/approach – The study utilized two methodologies to efficiency estimation: data envelopment analysis (DEA) and the stochastic frontier. DEA uses mathematical programming techniques and does not impose any functional form on the data. However, it attributes all deviation from the mean function to inefficiencies. The stochastic frontier utilizes econometric techniques. Findings – The test for structural differences in the two periods does not show any statistically significant differences between the two periods. However, both methodologies show a decline in efficiency levels from 1992, with the lowest period experienced in 1998. From then on, efficiency levels began to increase. Originality/value – To the best of the authors' knowledge, this is the first paper to use both methodologies in the sugar industry in Kenya. It is shown that in industries where the noise (error) term is minimal (such as manufacturing), the DEA and stochastic frontier give similar results.

Continous annular chromatography for the separation of carbohydrate mixtures

The continuous separation of beet molasses resulting in a sucrose rich product and a non-sugar waste product was carried out using a rotating annular chromatograph. The annulus was 12 mm wide and 1.4 m long and was packed with a sodium charged 5.5% cross-linked polystyrene ion exchange resin. Separation was achieved by the simultaneous mechanisms of ion exclusion, size exclusion and partition chromatography. The entire packed bed was slowly rotated while beet molasses was fed continuously through a stationary feed nozzle to the top of the bed. Each molasses constituent having a different relative affinity for the packing and the deionised water mobile phase describes a characteristic helical path as it progresses from the stationary feed point to the bottom of the rotating bed. Each solute then elutes from the annulus at a different angular distance from the feed and separation of the multicomponent mixture is thereby achieved. When a 35% w/w sucrose beet molasses feed was used the throughput achievable was 45.1 kg sucrose m~3 resin h"1. In addition to beet molasses separation other carbohydrate mixtures were separated. In particular the separation of glucose and fructose by Ligand exchange chromatography on a calcium charged ion exchange bed was carried out. The effects of flowrates, concentration, rotation rate, temperature and particle size on resolution and dilution of constituents in the mixtures to be separated were studied. A small test rig was designed and built to determine the cause of liquid maldistribution around the annulus. The problem was caused by the porous bed support media becoming clogged with fines being introduced by eluent flows and off the resin. An outer ring was constructed to house the bed support which could be quickly replaced with the onset of maldistribution. The computer simulation of the operation of the rotating annular chromatograph has been carried out successfully.

The production of fructose from carbohydrate feedstocks

A review of the general chromatographic theory and of continuous chromatographic techniques has been carried out. Three methods of inversion of sucrose to glucose and fructose in beet molasses were explored. These methods were the inversion of sucrose using the enzyme invertase, by the use of hydrochloric acid and the use of the resin Amberlite IR118 in the H+ form. The preferred method on economic and purity considerations was by the use of the enzyme invertase. The continuous chromatographic separation of inverted beet molasses resulting in a fructose rich product and a product containing glucose and other non-sugars was carried out using a semi-continuous counter-current chromatographic refiner (SCCR6), consisting of ten 10.8cm x 75cm long stainless steel columns packed with a calcium charged 8% cross-linked polystyrene resin Zerolit SRC 14. Based on the literature this is the first time such a continuous separation has been attempted. It was found that the cations present in beet molasses displaced the calcium ions from the resin resulting in poor separation of the glucose and fructose. Three methods of maintaining the calcium form of the resin during the continuous operation of the equipment were established. Passing a solution of calcium nitrate through the purge column for half a switch period was found to be most effective as there was no contamination of the main fructose rich product and the product concentrations were increased by 50%. When a 53% total solids (53 Brix) molasses feedstock was used, the throughput was 34.13kg sugar solids per m3 of resin per hour. Product purities of 97% fructose in fructose rich (FRP) and 96% glucose in the glucose rich (GRP) products were obtained with product concentrations of 10.93 %w/w for the FRP and 10.07 %w/w for the GRP. The effects of flowrates, temperature and background sugar concentration on the distribution coefficients of fructose, glucose, betaine and an ionic component of beet molasses were evaluated and general relationships derived. The computer simulation of inverted beet molasses separations on an SCCR system has been carried out successfully.

Solid-supported boronic acid conjugates for sugar and glycopeptide recognition

The Fmoc synthetic strategy was employed to synthesise two identical combinatorial peptide libraries on a hydrophilic PEG-PS resin. One library was appended with boronic acid moieties at two positionally-fixed locations. Successful inclusion of the boronic acid units was confirmed using a novel UV fluorescent colorimetric assay employing carminic acid as the dye compound. A study of the effect had by the resin-bound peptides bearing boronic acid groups on the binding characteristics of vancomycin, a medically relevant antibiotic glycoprotein, was conducted. In all, 132 library compounds were tested for their binding affinity with vancomycin, via immobilisation of the glycopeptide onto the solid support through hydrogen bonding or complexation with the boronic acid moieties. Subsequent cleavage via acidolysis afforded vancomycin containing solutions which were quantified by growth inhibition of methicillin susceptible Staphylococcus aureus. Comparison of the diameters of the resultant zones of inhibition and those produced by vancomycin of known concentrations afforded a means of calculating the vancomycin concentration of the cleavage solutions, and thereby determining the binding affinity of vancomycin to each peptide sequence. Five peptide sequences and twenty one of the peptidyl-boronic acid sequences showed zones of inhibition, demonstrating their reversible affinity for vancomycin. Three peptide sequences showed zones of inhibition in both libraries. The presence of boronic acid was therefore shown to impart, enhance, detract and remove the affinity of vancomycin to a range of resin-bound peptide sequences.

Biodeterioration of harvested sugar cane in Jamaica

The microbiological, physical and chemical changes which occur instored, harvested sugarcane were studied in Jamaica and the United Kingdom.The degree of deterioration was proportional to time of storage, and wasrevealed by a statistically significant reduction in sucrose content.Other symptoms included a fall in pH, and increases in reducing sugars,dextran, viscosity, and microbial count. Cut cane was universally infectedwith Leuconostoc mesenteroides, which reached a maximum count of 107 to 108organisms per ml. juice within. 3 to 4 days of harvest. Counts of othermicroorganisms were generally insignificant, except for occasional lactobacilli.A new dextran-forming species was named Lactobacillus confusus.Microorganisms isolated from deteriorated cane were screened for theirability to cause deterioration of a sterile, synthetic cane juice. L. mesenteroides strains were the most deteriogenic, but attempts toreproduce the symptoms of "sour" cane by inoculation of this organism intocut cane were only partially successful. L. mesenteroides was present in the soil and the epiphytic flora of the stalk. The principal vector of infection appeared to be the cutters' machete, especially in wet weather. Cane harvested by a chopper machine deteriorated more rapidly than hand-cut whole-stalks. Economic losses due to deterioration of harvested cane were estimated to be 9.2% of the initial recoverable sugar for the 1969 crop at Frome Estate, Jamaica. Dextran content was a useful indicator of cane biodeterioration. The dextran content of mill juices was correlated with rainfall, and significant correlations were obtained between dextran content and viscosity of mill syrups and the amount of sugar lost in final molasses; it also caused the formation of elongated crystals. Attempts to control sour cane by chemical and physical methods were unsuccessful, and it was concluded that the only solution is to mill cane within 24 hours of harvest. A novel method for removal of dextran from mill juices by enzymic treatment with dextranase was developed and patented.

Aggregation and caking processes of granular materials:continuum model and simulation with application to sugar

Aggregation and caking of particles are common severe problems in many operations and processing of granular materials, where granulated sugar is an important example. Prevention of aggregation and caking of granular materials requires a good understanding of moisture migration and caking mechanisms. In this paper, the modeling of solid bridge formation between particles is introduced, based on moisture migration of atmospheric moisture into containers packed with granular materials through vapor evaporation and condensation. A model for the caking process is then developed, based on the growth of liquid bridges (during condensation), and their hardening and subsequent creation of solid bridges (during evaporation). The predicted caking strengths agree well with some available experimental data on granulated sugar under storage conditions.

Sugar and coffee: A history of settler agriculture in nineteenth-century Liberia

This dissertation is about commercial agriculture in nineteenth-century Liberia. Based primarily on the archives of the American Colonization Society (founder of Liberia), it examines the impact of environmental and demographic constraints on an agrarian settler society from 1822 to the 1890s. Contrary to the standard interpretation, which linked the poor state of commercial agriculture to the settlers' disdain for cultivation, this dissertation argues that the scarcity of labor and capital impeded the growth of commercial agriculture. The causes of the scarcity were high mortality, low immigration and the poverty of the American “Negroes” who began to settle Liberia in 1822. ^ Emigration to Liberia meant almost certain death and affliction for many immigrants because they encountered a new set of diseases. Mortality was particularly high during the early decades of colonization. From 1822 to 1843, about 48 percent of all immigrants died of various causes, usually within their first year. The bulk of the deaths is attributed to malaria. There was no natural increase in the population for this early period and because American “Negroes” were unenthusiastic about relocation to Liberia, immigration remained sparse throughout the century. Low immigration, combined with the high death rate, deprived the fledgling colony of its potential human resource, especially for the cultivation of labor-intensive crops, like sugar cane and coffee. Moreover, even though females constituted approximately half of the settlers, they seldom performed agricultural labor. ^ The problem of labor was compounded by the scarcity of draft animals. Liberia is in the region where trypanosomiasis occurs. The disease is fatal to large livestock. Therefore, animal-drawn plows, common in the United States, were never successfully transplanted in Liberia. Besides, the dearth of livestock obstructed the development of the sugar industry since many planters depended on oxen-powered mills because they could not afford to buy the more expensive steam engine mills. ^ Finally, nearly half of the immigrants were newly emancipated slaves. Usually these former bondsmen arrived in Liberia penniless. Consequently, they lacked the capital to invest in large-scale plantations. The other categories of immigrants (e.g., those who purchased their freedom), were hardly better off than the emancipated slaves. ^

Raising Cane in the 'Glades: The Global Sugar Trade and the Transformation of Florida

Over the last century, the Everglades underwent a metaphorical and ecological transition from impenetrable swamp to endangered wetland. At the heart of this transformation lies the Florida sugar industry, which by the 1990s was at the center of the political storm over the multi-billion dollar ecological “restoration” of the Everglades. Raising Cane in the ’Glades is the first study to situate the environmental transformation of the Everglades within the economic and historical geography of global sugar production and trade. Using, among other sources, interviews, government and corporate documents, and recently declassified U.S. State Department memoranda, Gail M. Hollander demonstrates that the development of Florida’s sugar region was the outcome of pitched battles reaching the highest political offices in the U.S. and in countries around the world, especially Cuba—which emerges in her narrative as a model, a competitor, and the regional “other” to Florida’s “self.” Spanning the period from the age of empire to the era of globalization, the book shows how the “sugar question”—a label nineteenth-century economists coined for intense international debates on sugar production and trade—emerges repeatedly in new guises. Hollander uses the sugar question as a thread to stitch together past and present, local and global, in explaining Everglades transformation.

Sugar Feeding Affects the Male Contribution in Reproduction in Aedes Aegypti

Juvenile hormone (JH) is crucial for the stimulation and progression of oogenesis from emergence to the previtellogenic resting stage in female Aedes aegypti mosquitoes. Juvenile hormone has been suggested to be among the many substances transferred form the male accessory glands to the female during copulation but no evidence for this has previously been provided. Quantification of JH III in the accessory glands of males and in the bursae copulatrix and spermathecae of mated females was performed using HPLC-FD. These amounts were measured in relation to the quality of adult sugar feeding in the male. The effect of this variable transfer was measured on two fecundity markers that occur during the previtellogenic stage of oogenesis, specifically follicular resorption and ovarian lipids. Male mosquitoes provided with 20% sucrose contained ~ 60% greater amount of JH in the accessory glands and transferred 4 fmol more JH during copulation than males provided with 3% sucrose. These differences resulted in a nearly 40% reduction in follicular resorption and an approximate 3-fold increase in lipid content in the ovaries of mated females during the previtellogenic stage. These results suggest that the contribution of JH from the male is dependent on the quality of nutrition obtained during adult sugar feeding. Female fecundity is likely responsive to these variable previtellogenic effects, possibly resulting in a difference in the number of eggs laid. Improvements in female reproductive output may have wider implications in the transmission of diseases attributed to this important arbovirus vector.

Sugar and Revolution ( A Requiem) , Lecture by Duanel Díaz Infante

This flyer promotes the event "Sugar and Revolution ( A Requiem) : Lecture by Duanel Díaz Infante", cosponsored by FlU's Cuban Research Institute, Latin American and Caribbean Center, and the FlU Libraries.

Stabilisation of dehydrated nanoemulsions using sugar - protein matrices

There are numerous review papers discussing liquid nanoemulsions and how they compare to other emulsion systems. Little research is available on dried nanoemulsions. The objectives of this research were to (i) study the effect of varying the continuous phase of nanoemulsions with different carbohydrate/protein ratios on subsequent emulsion stability, and (ii) compare the physicochemical properties, lactose crystallisation properties, microstructure, and lipid oxidation of spray dried nanoemulsions compared to spray dried conventional emulsions having different water and sugar contents. Nanoemulsions containing sunflower oil (10% w/w), β-casein (2.5–10% w/w) and lactose or trehalose (10–17.5%) were produced following optimisation of the continuous phase by maximising and minimising viscosity and glass transition temperature (Tg’) using mixture design software. Increasing levels of β-casein from caused a significant increase in viscosity, particle size, and nanoemulsion stability, while resulting in a decrease in Tg’. Powders were made from spray drying emulsions/nanoemulsions consisting of lactose or a 70:30 mixture of lactose:sucrose (23.9%), sodium caseinate (5.1%) and sunflower oil (11.5%) in water. Nanoemulsions, produced by microfluidisation (100 MPa), had higher stability and lower viscosity than control emulsions (homogenization at 17 MPa) with lower solvent extractable free fat in the resulting powder. Partial replacement of lactose with sucrose decreased Tg and delayed Tcr. DVS and PLM showed that in powdered nanoemulsions, lactose crystallises faster than in powdered conventional emulsions. Microstructure of both powders (CLSM and cryo-SEM) showed different FGS in powders and different structure post lactose crystallisation. Powdered nanoemulsions had lower pentanal and hexanal (indicators of lipid oxidation) after 24 months storage due to their lower free fat and porosity, measured using a validated GC HS-SPME method, This research has shown the effect of altering the continuous phase of nanoemulsions on microstructure of spray dried nanoemulsions, which affects physical properties, sugar crystallisation, and lipid oxidation.