Bio-hydrogen production by photo-fermentation of dark fermentation effluent with intermittent feeding and effluent removal

Pure culture of Rhodobacter sphaeroides (NRRL- B1727) was used for continuous photo-fermentation of volatile fatty acids (VFA) present in the dark fermentation effluent of ground wheat starch. The feed contained 1950 ± 50 mg L⁻¹ total VFA with some nutrient supplementation. Hydraulic residence time (HRT) was varied between 24 and 120 hours. The highest steady-state daily hydrogen production (55 ml d⁻¹) and hydrogen yield (185 ml H₂ g⁻¹ VFA) were obtained at HRT = 72 hours (3 days). Biomass concentration increased with increasing HRT. Volumetric and specific hydrogen formation rates were also maximum at HRT = 72 h. High extent of TVFA fermentation at HRT = 72 h resulted in high hydrogen gas production.     

The Effect of Zn Substitution of Ca in BiPbSrCaCuO Superconductors Sintered at 830 °C

The effect of partial substitution of Ca by Zn in Bi_1.7Pb_0.3Sr₂Ca_2−x Zn _x Cu₃O _y at x=0.00, 0.05, 0.10, 0.15 and 0.20 levels on the electrical and structural properties was investigated in this work. The characterization of the ceramics prepared by the conventional solid-state reaction method were done by resistance–temperature measurements, XRD, SEM and density analysis. Low levels of Zn substitution of Ca caused significant changes in the properties of the ceramics. The low-T _c superconducting properties were enhanced and the fraction of the low-T _c (2212) phase were found to increase at x=0.15 level of Zn substitution at 830 °C sintering temperature. Zero resistance was observed only in sample D with x=0.15 and the T _c was determined as 92 K. The SEM micrographs and the density analysis have shown that this was the densest packed ceramic.     

Usage of solar-assisted spouted bed drier in drying of pea

The main objective of this study is to evaluate the effects of solar-assisted spouted bed and open sun drying on the drying rate and quality parameters of pea. Color, shrinkage, bulk and apparent densities, internal and bulk porosities, rehydration capacity and microstructure were the quality parameters investigated in dried product.Drying rate for solar-assisted spouted bed was about 3.5 times of drying rate for open sun drying. Air temperature changed between 20 °C and 27.4 °C during open sun drying while temperature of air at the inlet of solar-assisted spouted bed dryer varied between 35.3 °C and 65.5 °C during the experiments. Effective diffusivities were found to be 0.64 × 10^?10 and 3.27 × 10^?10 m²/s for open sun and solar-assisted spouted bed drying of pea, respectively. In color analysis, it was observed that a* value increased while b* value decreased for both drying methods. Bulk density and apparent density of peas dried under open sun was higher than that in solar-assisted spouted bed drier. In both drying methods, internal and bulk porosities decreased. Shrinkage was more for open sun dried samples. Rehydration capacity for solar-assisted spouted bed dried sample was higher than the one for open sun dried.     

Development of novel pea flour‐based nanofibres by electrospinning method

The aim of this study was to produce pea flour and hydroxypropyl methylcellulose (HPMC)‐based novel nanofibres using electrospinning method. The effects of pH, pea flour and HPMC concentration on apparent viscosity, electrical conductivity of electrospinning solutions and nanofibre characteristics were studied. Solutions were prepared at different pH values (7, 10, 12), with different pea flour concentrations (1%, 2% w/v) and HPMC concentrations (0.25%, 0.5%, 1.0% w/v). For all pea flour concentrations, k values increased significantly with increase in pH and HPMC concentration. It also increased with increase in pea flour concentration for basic solutions. Pea flour concentration increased diameter and water vapour permeability (WVP) values of nanofibres. This study showed that electrospinning was a promising method for fabrication of homogenous pea flour and HPMC‐based nanofibres to be used in packaging industry.     

Rheology,particle-size distribution,and stability of low-fat mayonnaise produced via double emulsions

In this study, the effects of the double emulsification method on the rheological properties, particle size, and stability of low-fat mayonnaise were studied. Different water-phase-to-oil ratios (2:8 and 4:6) of primary emulsions and different stabilizer types (sodium caseinate, xanthan gum, and lecithin-whey protein concentrate) were used to produce double-emulsified mayonnaise. As a control sample, mayonnaise was prepared conventionally. Sodium caseinate was found to be the most efficient stabilizer. In the presence of sodium caseinate, the stability and apparent viscosity of double-emulsified mayonnaise increased but their particle sizes decreased. It was found that flow behavior of double-emulsified and conventionally prepared mayonnaise could be described by the power law model. The double-emulsified mayonnaise samples were not different from the control samples in terms of stability and particle size. In addition, using the double emulsion method, it was possible to reduce the oil content of mayonnaise to 36.6%.     

EFFECTS OF HYDROCOLLOIDS ON APPARENT VISCOSITY OF BATTERS AND QUALITY OF CHICKEN NUGGETS

The effect of different types of starches and gums on batter consistency and the effect of batter consistency on quality parameters of deep-fat fried chicken nuggets were determined in this study. Consistency of batter was correlated with coating pickup and oil content of the product. Addition of different starch and gum species to batter was found to be effective for both viscosity development and quality attributes of deep-fat fried chicken nuggets. Hydroxypropyl methylcellulose gum (HPMC), xanthan gum, and pregelatinized starch provided the highest consistency to the batters. Amylomaize starch addition to the batter formulation provided about 50% increase in texture of nuggets as compared to the control. Chicken nuggets coated with batters containing HPMC, xanthan, or guar gum had the lowest oil content. HPMC reduced oil content by about 54%, while the reduction in oil content was 40% and 33% in the case of xanthan and guar gum addition, respectively.     

Quality of Gluten-Free Bread Formulations Baked in Different Ovens

The objective of this study was to determine the effects of different tigernut flour/rice flour ratios (0:100, 5:95, 10:90, 15:85, 20:80, and 25:75) on quality of gluten-free bread formulations baked in infrared–microwave combination and conventional ovens. The degrees of the starch gelatinization of breads baked in different ovens were also compared. Conventionally baked breads prepared with tigernut flour/rice flour ratio of 10:90 and the infrared–microwave combination-baked breads prepared with tigernut/rice flour ratio of 20:80 had the most acceptable firmness and specific volume values. These breads had also similar color. Tigernut flour had significantly higher gelatinization temperatures and lower gelatinization enthalpy (ΔH_g) values than rice flour (p?≤?0.05). As rice flour was replaced with tigernut flour, lower ΔH_g values were observed in dough samples. Breads baked in both conventional and combination oven had sufficient starch gelatinization degrees ranging from 91% to 94% and from 84% to 85%, respectively.     

Effects of dark/light bacteria ratio on bio-hydrogen production by combined fed-batch fermentation of ground wheat starch

Bio-hydrogen production by combined dark and light fermentation of ground wheat starch was investigated using fed-batch operation. Serum bottles containing heat-treated anaerobic sludge and a mixture of Rhodobacter sp. was fed with a medium containing 20 g dm^?3 wheat powder (WP) at a constant flow rate. The system was operated at different initial dark/light biomass ratios (D/L). The optimum D/L ratio was 1/2 yielding the highest cumulative hydrogen (1548 cm³), yield (65.2 cm³ g^?1 starch), and specific hydrogen production rate (5.18 cm³ g^?1 h^?1). Light fermentation alone yielded higher hydrogen production than dark fermentation due to fermentation of volatile fatty acids (VFAs) to H₂ and CO₂. The lowest hydrogen formation was obtained with D/L ratio of 1/1 due to accumulation of VFAs in the medium.     

Dark fermentative bio-hydrogen production from waste wheat starch using co-culture with periodic feeding: Effects of substrate loading rate

Dark fermentation experiments were performed for bio-hydrogen production from ground wheat starch solution (10 ± 1 g l⁻¹) using periodic feeding and effluent removal. A mixed culture of Clostridium butyricum-NRRL 1024 and Clostridium pasteurianum-NRRL B-598 were used with an initial biomass ratio of 1/1.Effects of wheat starch loading rate on the rate and yield of bio-hydrogen formation were investigated. Substrate loading rate was varied between 0.54 and 5.52 g d⁻¹ (HRT = 6-60 h). The highest hydrogen formation rate (280 ml d⁻¹), volumetric hydrogen formation rate (1857 ml H₂ l⁻¹ d⁻¹) and volatile fatty acids (VFAs) concentration were obtained with a substrate loading rate of 5.52 g d⁻¹ (HRT = 6 h). The highest hydrogen yield (109 ml H₂ g TS ⁻¹) was obtained with a substrate loading rate of 1.38 g d⁻¹.