Mineral and biological ice-nucleating particles above the South East of the British Isles.

A small fraction of aerosol particles known as Ice-Nucleating Particles (INPs) have the potential to trigger ice formation in cloud droplets at higher temperatures than homogeneous freezing. INPs can strongly reduce the water content and albedo of shallow mixed-phase clouds and also influence the development of convective clouds. Therefore, it is important to understand which aerosol types serve as INPs and how effectively they nucleate ice. Using a combination of INP measurements and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), we quantify both the INP concentrations over a range of activation temperatures and the size-resolved composition. We show that the INP population of aerosol samples collected from an aircraft over the UK during July of 2017 is consistent with ice-nucleation on mineral dust below about -20 °C, but some other INP type must account for ice-nucleation at higher temperatures. Biological aerosol particles above ∼2 µm were detected based on visual detection of their morphological features in all the analysed samples at concentrations of at least 10 to 100 L-1 in the boundary layer. We suggest that given the presence of biological material, it could substantially contribute to the enhanced ice-nucleation ability of the samples at above -20 °C. Organic material attached to mineral dust could be responsible for at least part of this enhancement. These results are consistent with a growing body of data which suggests mineral dust alone cannot explain the INP population in the mid-latitude terrestrial atmosphere and that biological ice nucleating particles are most likely important for cloud glaciation.

Iceland is an episodic source of atmospheric ice-nucleating particles relevant for mixed-phase clouds.

Ice-nucleating particles (INPs) have the potential to remove much of the liquid water in climatically important mid- to high-latitude shallow supercooled clouds, markedly reducing their albedo. The INP sources at these latitudes are very poorly defined, but it is known that there are substantial dust sources across the high latitudes, such as Iceland. Here, we show that Icelandic dust emissions are sporadically an important source of INPs at mid to high latitudes by combining ice-nucleating active site density measurements of aircraft-collected Icelandic dust samples with a global aerosol model. Because Iceland is only one of many high-latitude dust sources, we anticipate that the combined effect of all these sources may strongly contribute to the INP population in the mid- and high-latitude northern hemisphere. This is important because these emissions are directly relevant for the cloud-phase climate feedback and because high-latitude dust emissions are expected to increase in a warmer climate.

Contributions of biogenic material to the atmospheric ice-nucleating particle population in North Western Europe.

A minute fraction of atmospheric particles exert a disproportionate effect on the phase of mixed-phase clouds by acting as ice-nucleating particles (INPs). To understand the effects of these particles on weather and climate, both now and into the future, we must first develop a quantitative understanding of the major INP sources worldwide. Previous work has demonstrated that aerosols such as desert dusts are globally important INPs, but the role of biogenic INPs is unclear, with conflicting evidence for their importance. Here, we show that at a temperate site all INPs active above -18 °C at concentrations >0.1 L-1 are destroyed on heating, consistent with these INPs being of biological origin. Furthermore, we show that a global model of desert dust INPs dramatically underestimates the measured INP concentrations, but is consistent with the thermally-stable component. Notably, the heat sensitive INPs are active at temperatures where shallow cloud layers in Northern Europe are frequently observed to glaciate. Hence, we suggest that biogenic material is important for primary ice production in this region. The prevalence of heat sensitive, most likely biogenic, INPs in this region highlights that, as a community, we need to quantify the sources and transport of these particles as well as determine their atmospheric abundance across the globe and at cloud altitudes.

Industrial corn flour enrichment with whole amaranth flour and milling fractions in corn-based products.

Whole flour and milling fractions of raw amaranth seeds were used in 90:10, 80:20 and 50:50 mixtures with industrialized corn flour (MINSA) to prepare tortillas and arepas, basic nutritional foods in several Latin American countries. The three corn-amaranth mixtures showed a good protein and fat content as well as amino acid profile, and presented adequate physical characteristics for making tortillas. Amaranth whole flour and commercial corn flour mixtures in the proportion of 80:20 and 50:50 were found suitable for the preparation of arepas. Protein and fat content were substantially improved, with no changes in organoleptic characteristics. The Mexican type of Amaranthus cruentus, selected due to its availability and bromatologic properties, yielded products of excellent nutritional quality, according to their amino acid content and protein efficiency ratio (PER). The protein-rich (1R) and starchy (2-R) fractions obtained by air classification, also yielded good results when substituting amaranth flour. The afore-mentioned flours and air-classified fractions of the 50:50 mixtures proved to be adequate in gruel preparations when used in 1:8 and 1:12 dilutions, as they improved their organoleptic characteristics. Flakes and extrudates were also used, yielding products with a 13.3-15% protein content, 1.7-3.7% fat, and 65.2-74.2% carbohydrates. In addition, extrudates were utilized to prepare snacks of better nutritional quality than existing similar commercial products. Improvement of the tortilla's mineral and fatty acid contents was achieved in every case. Enrichment of this product with whole amaranth flour is, therefore, recommendable for use in programs aimed at improving the nutritional status of the population.

Effect of heat treatment and milling on the seed, flour, rheology and baking quality of some amaranth ecotypes.

Forty-five harvests corresponding to the two predominating domestic species of amaranth in Mexico were studied. The proximate analysis revealed some statistically significant differences throughout three years of observation. The Ca, P and Fe content did not vary greatly in 15 samples. No chemical differences were either manifested in the Mercado and Aztec types of A. hypochondriacus, nor in the Mexican type of A. cruentus. The latter exhibits a higher grain yield and a shorter life cycle; however, its baking quality is apparently inferior to that of the Mercado type of A. hypochondriacus. The heat treatment of the seeds (toasting, popping and cooking) affected protein and lysine contents as does in cereals and leguminous seeds although toasting in particular improves its sensory characteristics without altering digestibility and PER. Popping only improves PER. Heating at 90 or 170 degrees C for three to five minutes, at the usual seed's moisture rate of 6 to 15%, does not affect protein content and does so only slightly in the case of the fatty acids content. Amylographic and farinographic values of the starchy fractions indicate similarities to C. quinoa and differences with respect to wheat. In the case of "amaranth milk", viscosity and gelatinization temperature produced satisfactory values. The extension of amaranth cultivation in the country is hereby suggested in view of the seed's nutritional quality, and considering the behavior of whole amaranth flour and its fractions.

Milling procedures and air classification of amaranth flours.

The different milling characteristics of Amaranthus cruentus, a domestic variety prevailing in Mexico, selected as representative sample, are herein discussed. This was subjected to proximate analysis, which confirmed its good quality. Milling trials were carried out for the preparation of whole flour by means of conventional mills and by combining some of these with the Raymond and Alpine separators for air classification. Results were then compared to those obtained with a Strong-Scott pearler. Grits and bran contained the highest protein concentration. After comparing overall results, it may be concluded that the best operating conditions are the following: a) seed pearling using five passes, in a pearler, with variable yields of approximately 22% containing 36% protein, and b) combining the Miag mill and Raymond air separator, with variable yields of approximately 32% and a protein content of 30-36%. Proximate analysis of the fractions as well as farinographic and amylographic characteristics--different from those of whole wheat and amaranth flours--suggest their use in the preparation of nutritionally-enriched food products.

Development and evaluation of a low-cost amaranth (Amaranthus cruentus) containing food for preschool children.

A powdered blend for feeding preschool children was prepared from whole amaranth (Amaranthus cruentus) seeds, pearled oats, soybeans, sucrose and vegetable oil. The blend was similar in proximal chemical analysis and total caloric content, and identical in calorie distribution and vitamin and mineral patterns to a soy/oats infant formula previously developed. The amaranth blend equalled the FAO/WHO 1973 children's pattern in tryptophan and exceeded this pattern, as well as the soy/oats formula in all other essential amino acids; it reflected higher PER than casein and the soy/oats formula. In feeding trials with children 1-3 years of age, no significant differences in weight gain was observed when either product was fed. The anticipated cost of the amaranth blend is 6% lower than that of the soy/oats formula.

Effect of trace elements on citric acid fermentation by Aspergillus niger.

Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of Aspergillus niger in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH(4)NO(3), 0.20; KH(2)PO(4), 0.10; MgSO(4).7H(2)O, 0.025; and (mg/liter): FeSO(4), 0.15 to 0.75; ZnSO(4), 0.10; and CuSO(4), 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%, pH of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements.

Sugar substrates for L-lysine fermentation by Ustilago maydis.

The extracellular production of l-lysine in media with cane sugar, blackstrap molasses, or clarified sugar-cane juice by a previously obtained mutant of Ustilago maydis was studied. Enzymatically inverted clarified juice (medium J-3) gave 2.9 g of lysine per liter under the following conditions: inoculum, 5%; pH 5.8; temperature, 30 C; K(La) in the fermentors, 0.41 mmoles of O(2) per liter per min; fermentation time, 72 hr. The concentrate, obtained by direct evaporation and drying of the fermentation broth, could be used as a possible feed supplement because of its amino-acid and vitamin content.

Chemical and nutritional evaluation of two amaranth (Amaranthus cruentus)-based infant formulas.

The objective of this study was to calculate, prepare and evaluate the Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) of two infant formulas made with amaranth (Amaranthus cruentus). Both formulas were formulated to match a previously developed and tested soy-oats infant formula. No significant differences were found between the three formulas with respect to corrected Protein Efficiency Ratio (P.E.R.) and Net Protein Utilization (N.P.U.) values. Only the product made with the 1-R fraction of amaranth was found to have a significantly lower P.E.R. than casein.