The influence of sodium caseinate on the physical properties of spray‐dried honey

The aim of this work was to spray dry honey (rape and buckwheat varieties) with Arabic gum (AG) as a carrier alone or in combination with sodium caseinate (1% and 2% w/w NaCas) as a drying aid. Powder recovery ranged from 66.2 ± 0.7% to 75.8 ± 4.9%, and the values were significantly higher for samples containing NaCas. Powders were characterised by good flowability, the addition of NaCas had positive impact on this factor. However, the hygroscopicity of protein‐containing powders was higher, especially at 2% w/w of NaCas. Powders hygroscopicity was related to particle size: AG powder of the smallest particle size was the most hygroscopic, while the particle size did not affected flowability, which was strongly related to the feed solution composition. Based on the obtained results, it was concluded that the addition of 1% w/w of NaCas as a drying aid during buckwheat and rape honey spray drying with Arabic gum as a carrier is favourable, while the further increase of protein content does not give additional benefits.     

Hydrogen production by propylene-assisted decomposition of methane over activated carbon catalysts

Catalytic decomposition of methane (CDM) permits obtaining hydrogen in high yields and – what is essential – it does not lead to release of CO₂. Unfortunately, most of the catalysts used in this process undergo fast deactivation. Their possible regeneration, consisting in the removal of pore blocking carbonaceous deposit of low catalytic activity, leads to generation of undesirable carbon dioxide. An alternative solution for maintaining high catalyst activity in the CDM reaction can be generation of the catalytically active carbonaceous deposit on its surface. Such a deposit can be obtained by decomposition of different organic substances. This paper reports on methane decomposition carried out in the presence of propylene (used in the concentration of 10 or 20%). The reaction was performed at three temperatures of 750 °C, 850 °C or 950 °C. Three types of activated carbon were tested as catalysts: the first one was obtained by activation of pine wood biomass with Na₂CO₃, whereas the second and third ones were commercial carbons (WG-12 and Norit RX3 Extra). According to the results, the addition of propylene to the CDM system effectively reduces deactivation of the activated carbon catalysts and permits fast stabilisation of their catalytic activity at a high level.     

A new generation of sludge-based adsorbents for H2S abatement at room temperature

The present paper discusses H2S removal by a new generation of sewage-sludge-derived materials which are characterized by their outstanding textural properties when compared to previous materials obtained by pyrolysis and/or activation of similar precursors. Alkaline hydroxide activation was used to prepare adsorbents/catalysts covering a wide range of porosities (SBET values from 10 to 1300 m2 g(-1)). Our results outline that textural properties are important for H2S abatement. However, not only highly porous sorbents, but also a high metallic content and a basic pH of these materials are required to achieve good performances. Proper combinations of textural properties and alkalinity render superior performances with retention values (x/M) as high as 456 mg of H2S removed per g of material. These retention capacities outperform previously published data for sewage-sludge derived materials and those achieved with commercial materials (including some activated carbons). Sulfur titration shows that most H2S is removed in the form of elemental sulfur, especially in the sewage/NaOH materials.     

Response of storage molds to different initial moisture contents of maize (corn) stored at 25 °C, and effect on respiration rate and nutrient composition

Maize was stored for 2 months in chambers maintained at 25 °C to simulate conditions observed in the central part of the “Corn Belt” of the United States when the grain warms because of high summertime temperatures after a period of winter storage. Maize was brought to three moisture contents (m.c.) within the range typically observed in farm and commercial storage, and was inoculated to simulate the amount of storage mold contamination typical of this situation. Certain of the experimental units were packed in insulation so that heat could accumulate within the grain masses to simulate hot spots. The wettest grain heated rapidly and became semi-anaerobic. The hot grain then dried rapidly, with the amount of moisture loss influenced by the ratio of water vapor pressures inside and outside the grain. The hot grain cooled and became more aerobic over time. New infections by storage molds, disappearance of viable field molds, development of kernel damage, and changes in atmospheric gases within the grain masses were correlated with the grain moisture or temperature and the rate at which the moisture and temperature changed. The rate of increase in new kernel damage was as high as 3.3% per week. Both the rate of respiration and the estimated ratio of starch to fat consumed were associated with the mean grain m.c. during the trial, and the estimated ratio of starch to fat consumed was in the range of 2.2/1–2.6/1 in the grain containing 16.6–18.2% m.c. That both fat and starch were consumed calls into question loss estimates based on starch metabolism alone. The fat content of the grain decreased more than 10% in some experimental units, but increased less than 5% in others. The protein content generally increased as other grain constituents were consumed.     

Bioactive compounds in rye flours with different extraction rates

Rye flours with extraction rate of 100% (wholemeal flour), 95% (brown flour), 90% (brown flour) and 70% (light flour) were prepared in order to study the relation between flour extraction rates and content of bioactive compounds. The following compounds were analysed: total phenolic compounds (TPC), total flavonoids (TF), inositol hexaphosphate (IP6), reduced (GSH) and oxidized (GSSG) glutathione, tocopherols (T) and tocotrienols (T3). The reduced/oxidized glutathione status (GSH/GSSG) of the flours was examined as a potential index of flour resistance against oxidative stress. The following observations were made in relation to the flour extraction rates and bioactive compounds contents: (a) milling process caused decrease in content in TPC, TF, IP6, GSH and GSSG, T and T3, (b) the most resistant against oxidation processes were suggested a brown flours, then light and finally wholemeal flour, (c) the ratio of tocotrienols to tocopherols (T3/T) was the highest in rye flours with extraction rate of 100–90% whereas light flour was the poorest source of tocopherols and tocotrienols. The provided data support current trend to increase number of rye products from wholemeal or brown flours.     

Parameters for the evaluation of the thermal damage and nutraceutical potential of lupin-based ingredients and food products

Foods based on sweet lupin proteins are gaining attention from industry and consumers because of their possible role in the prevention of cardiovascular disease. When promoting lupin-based foods for inclusion in a daily diet, the thermal damage suffered during processing is of relevance to the bioactive and nutritional quality of the food product. N-(2-furoylmethyl)-L-lysine (furosine) quantification demonstrates that currently available sweet lupin protein isolates have a thermal damage comparable to or lower than other traditional food ingredients, and are a good source of lysine in non-dairy products. In lupin-based foods claiming to have cholesterol-lowering potential, shotgun proteomics offers itself as a fast and effective screening method for assessing the biological availability of active peptides. Such a method is readily applicable to other legume-enriched food products.     

Biofuel developments in Mozambique. Update and analysis of policy,potential and reality

Climate change, rising oil prices and concerns about future energy supplies have contributed to a growing interest in using biomass for energy purposes. Several studies have highlighted the biophysical potential of biofuel production on the African continent, and analysts see Mozambique as one of the most promising African countries. Favorable growing conditions and the availability of land, water and labor are mentioned as major drivers behind this potential. Moreover, the potential of biofuel production to generate socio-economic benefits is reflected in the government’s policy objectives for the development of the sector, such as reducing fuel import dependency and creating rural employment. This article provides an overview of biofuel developments in Mozambique and explores to what extent reality matches the suggested potential in the country.