304. The gas-packing and storage of milk powder

1943 ◽  
Vol 13 (2) ◽  
pp. 162-215 ◽  
Author(s):  
C. H. Lea ◽  
T. Moran ◽  
J. A. B. Smith

The following summary of the effect of increasing quantities of oxygen in producing ‘off’ flavour in gas-packed full-cream milk powder during storage for long periods has been based on observations made in the present series of experiments, supplemented to some extent by results from later work on the gas storage of spray-dried powder which is not here reported in detail.(a) Full-cream powders stored in the presence of up to 0.01 ml. of oxygen per g. of powder kept very well at both normal and high temperatures. This figure corresponds to 1 % of oxygen (after completion of desorption) in the free-space gas of a can of spraydried powder packed to a bulk density of 0.55 g./ml., or to 0.5 % of oxygen in a can of roller powder packed to a bulk density of 0.35 g./ml. Tallowiness was never definitely detected under such conditions, and there seems to be little or no advantage to be gained, at least so far as palatability is concerned, by improving on this figure. An atmosphere containing not more than 0.01 ml. of oxygen per g. of powder can therefore be considered an ideal pack for milk powder.

1864 ◽  
Vol 13 ◽  
pp. 204-217

The experiments upon which I have been engaged for some time past, in connexion with the manufacture and properties of gun-cotton, have brought under my notice some interesting points in the behaviour of both gun. cotton and gunpowder, when exposed to high temperatures, under parti­cular conditions. I believe that these phenomena have not been previously observed, at any rate to their full extent, and I therefore venture to lay before the Royal Society a brief account of them. Being anxious to possess some rapid method of testing the uniformity of products obtained by carrying out General von Lenk’s system of manu­facture of gun-cotton, I instituted experiments for the purpose of ascer­taining whether, by igniting equal weights of gun-cotton of the same com­position, by voltaic agency, within a partially exhausted vessel connected with a barometric tube, I could rely upon obtaining a uniform depression of the mercurial column, in different experiments made in atmospheres of uniform rarefaction, and whether slight differences in the composition of the gun-cotton would be indicated, with sufficient accuracy, by a corre­sponding difference in the volume of gas disengaged, or in the depression of the mercury. I found that, provided the mechanical condition of the gun-cotton, and its position with reference to the source of heat, were in all instances the same, the indications furnished by these experiments were sufficiently accurate for practical purposes. Each experiment was made with fifteen grains of gun-cotton, which were wrapped compactly round the platinum wire; the apparatus was exhausted until the column of mercury was raised to a height varying from 29 inches to 29·5 inches. The flash which accompanied the deflagration of the gun-cotton was apparently similar to that observed upon its ignition in open air ; but it was noticed that an interval of time always occurred between the first application of heat (or incandescence of the wire) and the flashing of the gun-cotton, and that during this interval there was a very perceptible fall of the column of mercury. On several occasions, when the gun-cotton, in the form of “roving,” or loosely twisted strand, was only laid over the wire, so that it hung down on either side, the red-hot wire simply cut it into two pieces, which fell to the bottom of the exhausted vessel, without continuing to burn. As these results appeared to indicate that the effects of heat upon gun-cotton, in a highly rarefied atmosphere, differed importantly from those observed under ordinary circumstances, or in a very imperfect va­cuum, a series of experiments, under variously modified conditions, was instituted, of which the following are the most important.


1946 ◽  
Vol 14 (3) ◽  
pp. 378-399 ◽  
Author(s):  
J. D. Findlay ◽  
Constance Higginbottom ◽  
J. A. B. Smith

1. Storage tests on spray-dried full-cream milk powders prepared from milk preheated at 160,170,180, 190 and 200° F. for approximately 20 sec. and dried by the Krause process have been carried out at 47, 37 and 15° C. or room temperature. The storage tests were carried out independently at two different research stations. At the Hannah Institute the powders were packed in plain tin-plate containers as received from the factory. At Cambridge grease-free plain tin-plate and lacquered tin-plate containers were used. Deterioration was followed at both stations by a tasting panel and by determination of the amount of oxygen absorbed by the powder and of the accumulation of peroxide in the fat.2. When fresh the powder pre-heated at 180° F. had the best flavour, followed in order of preference by those pre-heated at 190 and 200° F., which had a definite but quite pleasant ‘boiled’ or ‘cooked’ flavour, and by those pre-heated at 160 and 170° F. which had an incipient tallowy flavour, but were nevertheless still acceptable. The 200 and 190° F. powders gave a strong reaction for volatile sulphur, the 180° F. powder a much weaker but quite definite reaction, and the 170 and 160° F. powders a negative reaction. The copper content of the 180° F. powder which, with the 170° F. sample, was the highest of the group, may have been partly responsible for the weakness of the reaction for volatile sulphur given by this sample. The solubility of the 180, 190 and 200° F. powders was not adversely affected by the high pre-heating temperatures, and the moisture contents of all the powders were sufficiently low to prevent any obvious loss of solubility, which remained very good indeed throughout the storage tests.


1894 ◽  
Vol 56 (336-339) ◽  
pp. 8-19 ◽  

During the last two years we have carried out a long series of experiments with explosive compounds for the purpose of studying chemical reactions at high temperatures and pressures, and of elucidating certain thermal constants relating chiefly to the specific heat of gases under such conditions. For these experiments we have principally used nitro-glycerin, nitro-cellulose, and several combinations of these two bodies which are used as smokeless gunpowders, for the reason that such modern explosives offer the advantage of not only presenting comparatively simple chemical reactions, owing to the absence of solid residue, but also of enabling considerable variations to be made in their composition so as to vary the proportions of the elements reacting.


2014 ◽  
Vol 14 (66) ◽  
pp. 9439-9453
Author(s):  
CN Ishiwu ◽  
◽  
JE Obiegbuna ◽  
JO Iwouno ◽  

Samples of spray-dried soy milk powder were produced at various spray-dryer inlet air temperatures and characterized. Soybean seed (Glycine max TAX 1448 – 2E Var.) was sorted, boiled for 40 min, manually dehulled, wet milled using plate mill and sieved with muslin cloth to obtain water soluble extract (soy milk). The soy milk was divided into two portions (samples A and B) and spray-dried using co-current spray dryer at a constant feed rate (20.5 ml/sec) but at air-inlet temperatures of 204oC and 260oC, respectively. Preliminary investigation carried out on this study showed that samples produced at air inlet temperatures below 200oC exhibited wet and agglomerated particles. The recovered powdered samples were analyzed for proximate composition, pH, available lysine, total solids, pack bulk density, viscosity, solubility and wettability at different reconstituting water temperatures, and sensory properties. Results showed that 38.60% and 45.55% yield (soy milk powder) were achieved at the end of the process for samples A and B respectively. The samples showed no significant differences (P ≥ 0.05) in some of these evaluated parameters such as fat, ash and pH. Soy milk powder showed high protein content (62.05±0.23%), fat (19.92±0.08%), ash (1.41±0.02 %) and available lysine (5.02±0.29%), but low carbohydrate content (12.85±0.01 %) and moisture (3.66±0.23%). The physical properties showed that the mean total solid of the samples was 10.33±0.33%, pack bulk density (0.57±0.00 g/ml), while the mean viscosity was 47 mpas. The sample spray-dried at 204oC had solubilities of 48% and 78% at reconstituting water temperatures of 40oC and 80oC, respectively while the sample produced at 260°C showed lower solubility of 38.46% and 45.01% when temperature of reconstitution were 40oC and 60oC, respectively. However, the sample produced at 260oC exhibited decreased solubility when the reconstituting water temperature was raised above 60oC. Its solubility was 40.39% at reconstituting water temperature of 70oC which further decreased to 38% at 80o C. The wettability of the samples steadily decreased as the reconstituting water temperature increased from 40 to 80oC. The wettability of the sample spray-dried at 204oC decreased from 36 to 22 sec, while that of sample spray-dried at 260oC decreased from 29 to 18 sec. Sensory scores showed that the sample spray-dried at 204oC was preferred to the sample spray-dried at 260oC.


Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.


Author(s):  
Cindy T. Sepúlveda ◽  
Ailén Alemán ◽  
José E. Zapata ◽  
M. Pilar Montero ◽  
M. Carmen Gómez-Guillén

Proceedings ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 2
Author(s):  
Noé Anes García ◽  
Antonio Luis Marqués Sierra

In recent years, developments made to reduce the consequences generated using petroleum products have been strengthening; therefore, biofuels have become a requirement in different countries worldwide with the objective of reducing not only the high levels of current pollution, but also mitigating the effects generated by global warming. Despite the advances that have been made in the field of research on Jatropha, it is still necessary to carry out more detailed studies aimed at achieving a better use of it, identifying the influence of its physical–chemical properties in terms of quality levels, as well as determining its behavior when mixed with palm oil to achieve a biodiesel with better yields, whose impact will be reflected mainly in the environmental field, helping to mitigate the production of greenhouse gases that are produced by petroleum products. Although currently the biofuels sector has made important advances in research, it is necessary to deepen the physical–chemical analyses both in the production and storage processes of biodiesel, so that in the future it can be fully fulfilled with the energy requirements that are currently only achieved with fossil fuels, so it is necessary to direct this research toward the development of new products with improved characteristics, especially when exposed to prolonged storage times and low temperatures.


1955 ◽  
Vol 53 (4) ◽  
pp. 387-397 ◽  
Author(s):  
P. H. R. Anderson ◽  
Doris M. Stone

SummaryEight explosive outbreaks of food poisoning, occurring in school canteens in England during 1953 and affecting 1190 known cases, are described. The clinical features were characteristic of the toxin type of illness. No deaths occurred.The food causing all of these outbreaks was prepared from spray-dried skim milk powder. It was not subsequently heat-treated and was usually consumed 3–4 hr. after preparation.The spray-dried milk powder proved to contain a high content of bacteria, including large numbers of Staph. aureus, of a phage pattern often associated with food poisoning. The assumption was therefore made that these outbreaks were caused by staphylococcal enterotoxin.Because the food was often consumed within 3–4 hr. of reconstitution of the milk powder—before, in fact, the staphylococci had had time to grow—it is concluded that the poisoning must have been due mainly to pre-formed toxin.Consideration is given to the opportunities for the formation of toxin in a spray-drying plant, and reasons are brought forward for believing that it is formed mainly in the balance tank where the warm milk is kept, sometimes for several hours, before passing into the final drying chamber.The processing of the milk and the precautions for preventing contamination of the finished product are discussed.


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