Liquid fuel resources and prospects for ligno-cellulosic ethanol: An Egyptian case study

Fossil fuels (oil, natural gas and coal) presently represent about 90% of the world’s total commercial primary energy demand. Yet, they are depletable sources of energy. Growth in the production of easily accessible oil, the main source of high energy liquid transportation fuels, will not match the projected rate of demand growth, especially in developing countries. In the transport sector, today, the only alternative to non-sustainable fossil fuels is biofuels that are produced from biomass, a stored environmentally neutral solar energy. These fuels are compatible with current vehicles and blendable with conventional fuels. Moreover, they share the long-established distribution infrastructure with little, if any, modification of equipment. The main biofuels presently in commercial production are bioethanol and biodiesel. Industrial countries started production of the 1st generation bioethanol and biodiesel from food products (grains and edible oil) since a few decades and these fuels are currently available at petrol stations. Second generation bioethanol from ligno-cellulosic materials is on the research, pilot and/or demonstration stage. This paper discusses the current situation regarding liquid fuels in Egypt which are experiencing imbalance between total production and demand for gasoline and diesel fuels. The quantified need for nonconventional sources is presented. Based on a thorough assessment of current and prospective generated agriculture residues as distributed over the political areas, mapping of the number and capacity of plants to be installed for production of bioethanol from available residues namely rice straw, sugar cane residues and cotton stalks has been developed. Annual capacities of 3000, 10,000 and 20,000 tons ethanol/year until year 2021 have been proposed. Capital and operating requirements and economic indicators have been estimated. It has been concluded that at current price of ethanol of about $0.6/kg, the simple rate of return on investments is about 2.8%, 11% and 16% for the 3000, 10,000 and 20,000 tons annual capacity ethanol respectively.     

Effect of different pretreatments on egyptian sugar-cane bagasse saccharification and bioethanol production

Sugar-cane processing generates large amount of bagasse. Disposal of bagasse is critical for both agricultural profitability and environmental protection. Sugar-cane bagasse is a renewable resource that can be used to produce ethanol.In this study, twelve microbial isolates, five bacteria, four yeasts and three filamentous fungi were isolated from sugar-cane bagasse. Bacterial and yeast isolates were selected for their ability to utilize different sugars and cellulose. Chipped and ground bagasse was subjected to different pretreatment methods; physically through steam treatment by autoclaving at 121 °C and 1.5 bar for 20 min and/or different doses of gamma γ irradiation (50 and 70 Mrad). Autoclaved pretreated bagasse was further biologically treated through the solid state fermentation process by different fungal isolates; F-66, F-94 and F-98 producing maximum total reducing sugars of 18.4., 26.1 and 20.4 g/L, respectively.Separate biological hydrolysis and fermentation (SHF) process for bagasse was done by the two selected fungal isolates; Trichoderma viride F-94 and Aspergillus terreus F-98 and the two yeast isolates identified as Candida tropicalis Y-26 and Saccharomyces cerevisiae Y-39. SHF processes by F-94 and Y-26 produced 226 kg of ethanol/ton bagasse while that of F-98 and Y-39 produced 185 kg of ethanol/ton bagasse.     

Exposure assessment of mycotoxins in dairy milk

The objective of this study was to develop a quantitative Monte Carlo exposure assessment model for mycotoxins in dairy milk and to assess the potential human exposure levels. Mean concentrations of mycotoxins in milk were estimated using the simulation model (Aflatoxin M1 = 0.0161 μg/kg, Ochratoxin A = 0.0002 μg/kg, Deoxynivalenol = 1 μg/kg, Fumonisin B1 = 0.36 μg/kg, Zearalenone = 0.39 μg/kg, T-2 = 0.0722 μg/kg) while the simulated tolerable daily intakes (TDIs) from milk for males and females all fell below European Union guidelines. Aflatoxin M1 was the toxin of greatest concern as it had potential to exceed the EU limit of 0.05 μg/kg in milk. The sensitivity analysis identified the concentration of toxins in maize as the area which needs most attention in relation to crop management and agricultural practice. The sensitivity analysis assessed also identified the carry over rate as a factor closely related to risk and as a factor which required further research.     

Estimate of aflatoxin M1 exposure in milk and occurrence in Brazil

The presence of aflatoxin M₁ (AFM₁) was investigated in 125 samples of powdered milk, pasteurized milk and ultra high treated (UHT) milk in the city of São Paulo, and estimates of AFM₁ intake were assessed. The samples were analysed using an immunoaffinity column for cleanup and a HPLC-FLD for determining AFM₁. The quantification limit was 10 ng/kg. AFM₁ was found in 119 (95.2%) at levels ranging from 10 to 200 ng/kg with mean concentration of 31 ng/kg. The average daily intake estimated for AFM₁ was 1 ng/kg bw per day for children and 0.188 ng/kg bw per day for adults.     

Economic evaluation and sensitivity analysis of some fuel oil upgrading processes

Seven upgrading schemes, identified as high distillate production schemes have been proposed for upgrading of 3.50 × 10⁶ t/y atmospheric residues. The seven schemes were evaluated using the discounting cash flow method. Economic parameters such as internal rate of return, IRR, payback period, PBP and net present value, NPV have been calculated for each option.All studied schemes proved profitable with IRR ranging between 25.2 and 33.7% with option 7 having the highest NPV, IRR and payback period. Sensitivity analyses were performed on this option. The parameters investigated are: sales price (Revenue); production rate (feed weight); feed cost; utilities cost; direct and indirect costs; tax% and discount rate%. Their impact on NPV and %IRR has been evaluated. Tornado diagrams were constructed to illustrate the effect of variation of different cost parameters on NPV and IRR. The single most effective input variable is Revenue on both NPV and IRR. With two-factor sensitivity analysis, the two most important input variables for NPV and IRR are revenue and utilities.Spider charts for option 7 have been created to show how the model’s outputs depend on the percentage changes for each of the model’s input variables.     

High-performance liquid chromatographic determination of glycoalkaloids in potatoes from conventional,integrated, and organic crop systems

During the last decade organic agro-food products, including potatoes, have been progressively introduced in the Portuguese consumer market. Nevertheless, the quality of these products with regards to chemical safety still requires the implementation of monitoring programmes. In this communication we compare the glycoalkaloid content in varieties Santé and Raja of marketed Portuguese potatoes from conventional, integrated, and organic crop systems, using HPLC. In Santé tubers, the corresponding total amount of α-solanine and α-chaconine was respectively 37.3, 44.2, and 38.4 mg/kg fresh weight, whereas for Raja a decreasing concentration on the total glycoalkaloid content was observed from conventional (79.5 mg/kg) to integrated (59.6 mg/kg) and organic tubers (44.6 mg/kg).     

Sensor array for the combined analysis of water–sugar–ethanol mixtures in yeast fermentations by ultrasound

For the sugar fermenting industry, it is important to know the exact concentration values of sugar and ethanol in the process fluid during the alcoholic fermentation as an indicator for the fermentation progress. In this study, an ultrasound-based method for determining the concentration of sugar and ethanol simultaneously is presented. The ultrasound velocity in various binary (water–saccharose, water–ethanol) an ternary (water–saccharose–ethanol) mixtures in dependance of the temperature was measured with a pulse-echo method. The sugar and ethanol fraction in aqueous solutions cause an additive, but nonlinear component to the sound velocity of pure water dependant on the concentration and the temperature. A calibration model for the ultrasound velocity in water–sugar–ethanol mixtures was found by establishing a polynomial approach based on the experimental results. The coefficients of this polynom are obtained with a linear regression method by inserting the measurement points. The derived calibration function is continuous, monotone and relates one value of sound velocity to one certain set of concentration values and temperature unambiguously. By means of these mathematical properties, it can be shown that it is possible to determine the sugar and ethanol concentration values in water–sugar–ethanol mixtures only by measurement of the sound velocity at two different temperatures. The method is evaluated by determining the sugar-, respectively ethanol concentration in standardized water–saccharose–ethanol mixtures and in commercial beer probes with an accuracy of approximately 0.5 g/100 g up to 0.01 g/100 g.     

Monitoring the contents of biogenic amines in fish and fish products consumed in Korea

In order to obtain the level of biogenic amines in fish and fish products, a reversed phase high performance liquid chromatographic method was used for the quantitation of 12 biogenic amines in 300 fish and 80 fish products in Korea. Biogenic amines were extracted with hydrochloric acid, derivatized with dansyl chloride, separated using gradient elution, and detected by photodiode array and all detected biogenic amines were identified by UPLC/MS/MS. The detection levels of biogenic amines in the sample ranged from ND (not detected) to 30.6 mg/kg for agmatine, from ND to 390.0 mg/kg for cadaverine, from ND to 19.8 mg/kg for dopamine, from ND to 70.1 mg/kg for histamine, from ND to 17.8 mg/kg for noradrenaline, from ND to 29.7 mg/kg for 2-phenylethylamine, from ND to 43.0 mg/kg for putrescine, from ND to 11.9 mg/kg for serotonin, from ND to 9.5 mg/kg for spermidine, from ND to 13.5 mg/kg for spermine, from ND to 12.8 mg/kg for tryptamine, and from ND to 67.7 mg/kg for tyramine. Anchovy samples showed the high levels of histamine from 15.2 to 70.1 mg/kg, putrescine from 9.1 to 43.0 mg/kg, cadaverine from 152.2 to 90.0 mg/kg, and tyramine from 27.1 to 67.7 mg/kg. Agmatine was found at 30.6 mg/kg in cuttlefish. In the others fish samples agmatine detection levels were in the range from ND to 27.2 mg/kg. Spermidine and dopamine were detected about more than 85% samples in the range from ND to 19.3 mg/kg. Most of fish product samples showed less than 20 mg/kg of each biogenic amine. The maximum histamine and tyramine detection levels were respectively less than those of the regulation and recommendation.     

Incidence of zearalenone and fumonisins in Bulgarian cereal production

Ninty-one small-grain cereals (wheat, barley, maize) collected during the 2007 harvest in Bulgaria were tested for zearalenone (ZON) and fumonisins contamination. Analytical methods based on immunoaffinity clean-up and detection by liquid chromatography was used after validation. Limits of detection for ZON in different matrices were below 4.0 μg/kg in barley and wheat, and slightly higher for maize (17.6 μg/kg). The limit of quantification for ZON was 12 μg/kg in barley and wheat, and 58.8 μg/kg in maize. Recovery values ranged between 84% and 105%. The occurrence of ZON in cereals were rather low and only single incidences was found – up to 148 μg/kg for maize and 36.6 μg/kg for other cereals. Fumonisins in maize have showed a widespread distribution (in 94.7% of tested samples). One of the tested samples was contaminated above the established maximum limits for unprocessed maize.     

Validation of the procedure for the determination of aflatoxin B1 in animal liver using immunoaffinity columns and liquid chromatography with postcolumn derivatisation and fluorescence detection

The validation of the procedure for the determination of aflatoxin B₁ in animal liver (pig, chicken, turkey, beef, calf) was performed. The limit of detection (LOD) and limit of quantification (LOQ) were 2 ng/kg and 7.8 ng/kg, respectively. The repeatability of measurements, represented by the standard deviation (RSD_r) was 7.5%, 7.1%, and 4.8% at the contamination levels of 0.025 μg/kg, 0.050 μg/kg, and 0.075 μg/kg, respectively. The relative standard deviation for the within-laboratory reproducibility (RSD_R) was 18% at the level of 0.025 μg/kg and 22% at the levels of 0.050 μg/kg and 0.075 μg/kg. The measurement uncertainties at the same contamination levels were ±0.007 μg/kg, ±0.016 μg/kg, and ±0.023 μg/kg, respectively. The mean recovery was 72.8%, the decision limit (CCα) 0.063 μg/kg and the detection capability (CCβ) 0.080 μg/kg. The results indicate that the procedure is suitable for the determination of aflatoxin B₁ in animal liver and can be implemented for the routine analysis.     

A sensitive and validated method for determination of melamine residue in liquid milk by reversed phase high-performance liquid chromatography with solid-phase extraction

A sensitive and validated method for the determination of melamine residue in liquid milk is developed using reversed phase high-performance liquid chromatography-diode array detection (RP-HPLC-DAD) with solid-phase extraction (SPE). The conditions of the extraction, SPE and HPLC were investigated and optimized. The linearity is satisfactory in the range of 0.1–50 μg/mL with a correlation coefficient of 0.9998. Under the optimal conditions, the method limit of detection (LOD) and method limit of quantification (LOQ) were 18 μg/kg and 60 μg/kg, respectively. The recovery of melamine for milk samples spiked with 0.10–3 mg/kg was in the range of 85.5–99.3% with the RSDs (n = 3) of 2.3–3.7%. The intra-day assay precision (RSD) was 5.6% for five replicates of quality control milk sample at 2 mg/kg level. Confirmation of the identities of melamine was achieved by monitoring the two transitions in multiple-reaction monitoring (MRM) mode, and has been applied successfully for the determination of melamine residue in liquid milk samples. The confirmatory method can permit the detection of melamine residues at levels as low as 60 μg/kg in different liquid milks.     

The storage of grape marc: Limiting factor in the quality of the distillate

Grape marc, the mass of skins, stalks and seeds left after the winemaking process, is stored before distillation to produce ethanol by the alcoholic fermentation of the residual sugars. In this work 24 samples of grape marc were stored in four different types of containers. After distillation process, the samples obtained were analyzed by GC–MS to evaluate the influence that the storage exercises on the major volatile composition. Grape marc stored in plastic sacks (1000 kg) produced distillates with low values of the majority volatile compounds, that implies a good quality but a poor aromaticity. Distillates from pomace in plastic drums (250 kg) showed a high content in ethyl esters and higher alcohols, however the concentrations of ethyl acetate and aldehydes and acetal are high too, due to the difficulty to control the aerobic bacteria spoilage. The principal problem of the concrete containers (70,000 kg) is the high methanol production and in the plastic sacks (50 kg) the quick aerobic and anaerobic degradation. With an exhaustive control of oxygen contact, plastic drums and plastic sacks (1000 kg) were the better systems to storage grape marc before distillation.     

High contents of cadmium,lead, zinc and copper in popular fishery products sold in Turkish supermarkets

Selected toxic (cadmium, lead) and essential (zinc and copper) trace metals were determined by means of differential pulse stripping anodic voltammetry (DPSAV) in some different brands and kinds of fishery products purchased from the popular supermarkets of Turkey. Among the fishery products, the highest concentration of cadmium, lead, zinc and copper were found in the frozen anchovy (494.2 μg/kg, 314.2 μg/kg, 566 mg/kg, 45.7 mg/kg, respectively). While the canned anchovy fillet had the lowest cadmium (25.1 μg/kg), zinc (33.8 mg/kg) and copper (7.1 mg/kg) concentrations, canned tuna fish (Brand A) had the lowest lead (76.1 μg/kg). The concentrations of all toxic and essential elements in the selected products were high and often exceeded legal limits set by health authorities. Therefore these products must be monitored more often.     

Changes in the concentration of aflatoxin M1 during manufacture and storage of White Pickled cheese

In this study White Pickled cheese was produced from cow’s milk contaminated artificially with aflatoxin M₁ (AFM1) at two different levels, 1.5 and 3.5 μg/kg (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization at 72 °C for 2 min caused losses of AFM1 about 12% and 9%, respectively, in milk contaminated with 1.5 μg/kg AFM1, and 3.5 μg/l AFM1. These losses were found to be statistically significant (P < 0.01). After the cheese production, about 56% and 59% of total AFM1 remained in cheese–curd while about 32% of total AFM1 transferred to the whey for both 1.5 μg/kg and 3.5 μg/kg AFM1 contaminated milk. After 3-month storage in brine, AFM1 content of cheeses produced from 1.5 and 3.5 μg/kg AFM1 contaminated milks decreased by 2.9% and 2.8%, respectively. Changes in AFM1 content of cheese samples were found statistically insignificant (P > 0.05 and P > 0.01) for 3-month storage periods.     

Levels of aflatoxin M1 in milk,cheese consumed in Kuwait and occurrence of total aflatoxin in local and imported animal feed

A total of 321 milk samples (177 fresh, 105 long-life and 27 powdered milk, and 12 human milk), 40 cheese samples and 84 feed samples were analyzed for aflatoxin M1 (AFM1) and total aflatoxin. The samples were collected randomly during January 2005–March 2007, from Kuwaiti markets. The method used was ELISA technique. Results showed that all fresh milk samples except one were contaminated with AFM1 ranging from 4.9 to 68.7 ng/kg. Eight samples exceeded the EC’s regulatory limit. For the long-life milk samples, the ranges of AFM1 were from below the detection limit to 88.8 ng/kg, with four samples above the action limit of the EC. In the powdered milk samples, AFM1 ranged from 2.04 to 4.14 ng/kg. Of the human milk samples, only five were contaminated, with AFM1 levels ranging from 8.83 to 15.2 ng/kg with a mean 9.7 ng/kg. The cheese samples recorded 80% contamination with AFM1 with a range 23.8–452 and mean of 87.6 ng/kg, with one sample being above the regulatory limit (250 ng/kg) while the feed samples, showed 79.8% contamination with total aflatoxin.     

Effect of packaging and storage conditions on quality of shelled walnuts

The present study investigated the effect of packaging and storage conditions on quality of raw shelled walnuts. Walnut kernels were packaged in: (a) low density polyethylene (LDPE), 55 μm in thickness in air, (b) polyethylene terephthalate||polyethylene (PET||PE), 70 μm in thickness under N₂, and (c) PET-SiO_x||PE pouches, 62 μm in thickness under N₂. Samples were stored either under fluorescent light or in the dark at 4 or 20 °C for a period of 12 months. Quality parameters monitored were peroxide value (PV), hexanal, 2-thiobarbituric acid (TBA), odor, and taste of product. PV ranged between 0.3 for fresh walnut kernels and 31.4 meq O₂/kg oil for walnuts packaged in PE pouches exposed to light after 12 months of storage. Respective values for hexanal were <28.5 μg/kg and 36.0 mg/kg and for TBA ca. 0.2 and 11 mg MDA/kg. Values for odor ranged between 0.2 for fresh walnut kernels and 5.7 for walnut kernels packaged in PE exposed to light after 12 months of storage at 20 °C. Respective values for taste were 0.7 and 6.8. Taste proved to be a more sensitive attribute than odor. Based on shelf life (taste) values and PV data it is proposed that the upper limit value for PV is close to 10.0 meq O₂/kg walnut oil. Respective limit values for hexanal are 1–2 mg hexanal/kg walnut and for TBA is 1–2 mg malondialdehyde/kg walnut. Walnuts retained acceptable quality for ca. 2 months in PE-air, 4–5 months in PET||PE-N₂ and at least 12 months in PET-SiO_x||PE-N₂ pouches at 20 °C, with samples stored in the dark retaining slightly higher quality than those exposed to light. The effect of parameters investigated followed the sequence: temperature > degree of O₂ barrier > lighting conditions.     

The occurrence of volatile and semi-volatile aromatic hydrocarbons in virgin olive oils from north-eastern Italy

Twenty eight mono- (MAHs) and polyaromatic hydrocarbons (PAHs) were simultaneously determined in fifty-four virgin olive oils from three successive crops in the same geographical region. MAHs such as: toluene, C2-, C3- and C4-benzenes, and PAHs species containing 2, 3 and 4 aromatic rings were detected and quantified. MAHs were predominant in all of the samples, and had a mean concentration of 677 μg/kg. The mean concentration of total light PAHs was 80 μg/kg. Mean concentrations of C3- and C4-benzenes, which had not been previously quantified in olive oils, were 268 and 35 μg/kg, respectively. Finally, differences among crop years were evaluated, and the hypothetical daily intake of each aromatic hydrocarbon through virgin olive oil consumption was derived. The mean intake of single aromatic hydrocarbons ranged from 0.1 to 3.1 μg/day, while the mean exposures calculated for total MAHs and light PAHs were 15.6 and 1.8 μg/day, respectively.     

Deoxynivalenol reduction during the frying process of turnover pie covers

The effect of the frying process on deoxynivalenol contamination was evaluated. Deoxynivalenol naturally contaminated flour (1200 μg/kg) and fortified flour artificially contaminated (260 μg/kg) were used to prepare turnover pie dough covers. Frying was performed at three temperatures (169 °C, 205 °C and 243 °C) for different times. The final time for cooking at every temperature was established by measuring the colour during the frying process. Deoxynivalenol reduction was greater in the artificially contaminated samples (>66% at 169 °C, 43% at 205 °C and 38% at 243 °C). For the level of 1200 μg/kg, the average percentage of deoxynivalenol reduction, based on medians, was 28% when the dough covers were fried at 169 °C, 21% at 205 °C and 20% at 243 °C.     

Evaluation of immunoenzymatic methods for the detection of aflatoxin M1 in ewe’s milk

Ewe milk samples spiked with aflatoxin M1 (AFM1) at concentrations of 25, 50, 75 and 100 ng/kg were analysed by 5 different (Kits A to E) commercial Enzyme-Linked ImmunoSorbent Assay kits to evaluate the mycotoxin recovery average. The least accurate results of sensitivity were obtained at the 25 ng/kg concentration with underestimation in all cases. When the sample contamination-level was increased (50, 75 and 100 ng/kg), the results of four kits improved. Low coefficients of variation (3–14%) indicate good repeatability. Acceptable results of mean recoveries were obtained (47–60 ng/kg), especially at 50 ng/kg (EC Maximum Level) in all tests except Kit A. We conclude that Kits B, C, D and E are appropriate for the screening of AFM1 in ewe’s milk, but not for regulatory purposes.     

Aflatoxin M1 contamination in dairy products marketed in Iran during winter and summer

In the present study, 298 dairy product samples consisting of pasteurized milk (91 samples), yoghurt (68 samples), white cheese (72 samples), butter (31 samples) and ice cream (36 samples) collected from popular markets in four large Iranian cities were examined for aflatoxin M₁ (AFM₁) by thin layer chromatography (TLC) technique. The toxin was detected in 66 (72.5%) pasteurized milk samples (mean: 0.052 μg/l; range: 0.013–0.250 μg/l), 45 (66.1%) yoghurt samples (mean: 0.032 μg/kg; range: 0.015–0.119 μg/kg), 59 (81.9%) white cheese samples (mean: 0.297 μg/kg; range: 0.030–1.200 μg/kg), 8 (25.8%) butter samples (mean: 0.005 μg/kg; range: 0.013–0.026 μg/kg) and 25 (69.4%) ice cream samples (mean: 0.041 μg/kg; range: 0.015–0.132 μg/kg). The concentration of AFM₁ in 36.2%, 20.6%, 30.5%, 9.6% and 27.7% of pasteurized milk, yoghurt, white cheese, butter and ice cream samples, respectively, were higher than Iranian national standard limits. Levels of AFM₁ in samples of pasteurized milk, yoghurt, butter and ice cream collected in winter were significantly higher (P < 0.05) than those collected in summer. In the case of white cheese, level of AFM₁ was higher in winter than in summer, but the difference was not statistically significant (P > 0.05). The results indicated that the contamination of the dairy products in such a level could be a serious public health problem at the moment.