Use Of Raw Materials Research Articles

Encouraging prospects for recycling incinerated sewage sludge ash (ISSA) into clay‐based building products

AbstractStaffordshire University has recently completed a laboratory investigation into the potential utilisation of incinerated sewage sludge ash (ISSA) which has now become a serious disposal problem in the United Kingdom. This study involved a physical, chemical and ceramic evaluation of a source of ISSA produced at a newly commissioned sewage sludge incinerator sited near Manchester, initially to establish its level of variability on a day‐to‐day basis. Subsequently, feedstocks from two commercial brick factories both using raw materials of contrasting ceramic properties were obtained to examine the effect of their partial replacement by this source of ISSA. This work programme involved fabricating and firing experimental test‐samples (containing 5% dry w/w ISSA substitution) by the plastic‐extrusion forming method which is employed at both brickworks to manufacture their respective products. Standard ceramic testing procedures were subsequently carried out on the products containing ISSA and compared with those of the normal brick products fabricated in parallel. From the positive results obtained it is believed that the introduction of this source of ISSA as a new raw material for use in brick manufacture potentially offers attractive prospects. Moreover, its application in this identified role would provide an innovative alternative to its current landfill disposal, while also offering a direct contribution towards maximising the conservation of traditional brickmaking raw material reserves.© 2002 Society of Chemical Industry

Designer milks for the new millennium

Milk is an inherently expensive raw material for use as a food. To compete in the new millennium, dairy products will need to be based on special values that can only come from milk. These include traditional dairy products and health-giving products. Designer milks will be needed to give new, enhanced products and to improve the quality and value of traditional products. The use of milk for traditional products is likely to continue to be strong in western cultures. For these products, key issues are naturalness of supply, with “organic” milk being an important issue; and low-fat products, which may imply a need for lower fat milk. Health products are the most exciting new area for milk-based products. A number of components in milk are being recognised as conferring health benefits. These include minerals (calcium), peptides derived from milk proteins (ACE inhibitor peptide) and lipid components (conjugated linoleic acid). A number of harmful effects have been attributed to milk, often by groups with a vested interest, and often based on dubious data. We have investigated claims relating to diabetes, ischaemic heart disease and hypercholesterolaemia and been unable to substantiate any harmful effect. Designer milks that are improved raw materials can be approached through various combinations of genetics (including traditional genetics, marker-assisted selection and genetic modification of dairy cattle) and by farm and feed management. Examples are presented.

Towards an understanding of starch granule structure and hydrolysis

Starch constitutes a major component of foods and also a raw material for use in the production of industrial products. The constituent macromolecules of starch are packaged in a highly ordered and compact manner, resulting in inert, insoluble granules. Food processing destroys starch structure, thereby releasing the component molecules, which are subsequently made available for hydrolysis or serve a functional role in the food system. The application of starch as a raw material usually requires the prior disruption of the inert granule structure, which involves additional processing steps. The hydrolysis of native granules has ramifications at all levels of the food processing chain, from postharvest losses to nutritional consequences of the ingested food. Technologists have not been able to take advantage of, or control, this process because the body of the information that is available on starch granule structure and the behaviour of hydrolysing enzymes is still incomplete. In this review, I have highlighted some of the more recent advances in this field, with the view to opening up the way for more efficient native starch hydrolysis.

Optimal recycling of waste materials in a plastic extrusion production process

In a plastic extrusion production process, waste materials are created, reground and mixed with virgin plastic raw materials for use in the subsequent production cycles. The recycling of these waste materials helps to reduce the cost of using the more expensive virgin raw materials. However, the yield of the overall extrusion process decreases as a result. In this paper we develop a model to determine the optimal number of regrinding cycles for reusing these waste materials. The objective is to maximize the average profit per production batch. Analytical results are derived to compute the optimal number of cycles efficiently. Two characterizations of the melting index deterioration, which affects the yield of the extrusion process, are studied in detail. Numerical examples are provided to illustrate the results and to analyze the impact of various parameters on the optimal solutions.

Proteolysis and amino acid breakdown of heated and irradiated poultry byproducts and muscle tissue1

As a result of intensification and centralization of poultry slaughtering, the amount of slaughter byproducts produced at a single location is increasing. These byproducts are rich in protein, fat, and vitamins and, therefore, constitute a potentially useful raw material for use as animal feed. To maintain the nutritive value of these byproducts they should be processed to minimize or eliminate degenerative changes that reduce the feed value of the product. In this paper amino acid breakdown in slaughter-fresh poultry viscera, heads, and breast meat is studied as a model. Initial amino acid breakdown in viscera was observed (also when bacterial growth was excluded by gamma-irradiation), which resulted in high levels of total volatile N and cadaverine. Putrescine was produced only in viscera after bacterial proliferation. In heads and breast meat, no production of metabolites of amino acid degradation was observed as a result of initial enzymatic activity. It is concluded that during preservation of poultry byproducts not only bacterial proliferation, but also enzymatic breakdown of amino acids, must be prevented.

Mineralogic and physico-chemical studies of Lahad Datu bentonite

The commencement of production of activated clay by the local industry has created the demand for bentonite (montmorillonite) clay which is the basic raw material used in the manufacturing process. In the search for this material, field augering and sampling programme were undertaken in areas which collectively form the Segama Group near lahad Datu, Sabah. Seven samples, representing the total variation in a montmorillonite clay deposit, have been investigated for their mineralogic and physico-chemical characteristics. The mineral is dominantly a Ca-montmorillonite clay, with quartz, feldspar and zeolite as the main impurities. Early investigations by chemical and physical properties tests showed that this material could be suitable as a bleaching clay (or as a raw material for use in the manufacture of acid activated clay). The commercial appraisal of this clay deposit still depends on many experimental studies such as trial acid activation and bleaching tests of activated products on crude oil.

Mutagenicity studies in a tyre plant: in vitro activity of workers' urinary concentrates and raw materials.

The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant. Twenty three clerks (16 smokers) engaged in the administrative department of the same factory served as presumptive unexposed controls. XAD-2 resin concentrates of urine samples were assayed in the plate incorporation test and in the microtitre fluctuation assay with Salmonella typhimurium strains TA1535, TA98, and TA100. Furthermore, the in vitro mutagenicity of the major raw materials in use at the plant was determined in the plate incorporation assay with S typhimurium strains TA1535, TA1537, TA98, and TA100. The results obtained from the urinary mutagenicity study show that smoking habits, but not occupation, were statistically significantly related to the appearance of a urinary mutagenicity that was detectable with strain TA98. A possible synergistic effect of occupation with smoking was observed among tyre builders who were also smokers. The study of the raw materials showed that three technical grade materials were weakly active as mutagens in strain TA98 in the absence (poly-p-dinitrosobenzene) or in the presence of metabolic activation (mixed diaryl-p-phenylendiamines and tetramethyltiuram disulphide). The latter chemical was also weakly active in strain TA100.

Pharmaceutical and cosmetic uses of palm and lauric products

AbstractThe pharmaceutical and cosmetic industries are large and still growing. New products, astute marketing and sophisticated advertising have been very effective in these industries. They are more and more exacting and highly complex in their requirements. They require specification products with specific performance characteristics.The cosmetic industry and drug or pharmaceutical industries are defined. Information is given about the unique composition of palm and lauric oils which make them suitable raw materials for use in these applications.These two base oils are used in the form of triglycerides, whole fatty acids, fractionated fatty acids or fatty chemical derivatives. Information is given about these various ingredients, their use in specific cosmetic and pharmaceutical products and reasons for their use.Particular use is made of palmitic, stearic, myristic and short‐chain fatty acids. The derivatives would include glycerine esters, monostearates, other monoglycerides, propylene glycol esters, polyglycerol esters, sorbitans and sorbitan ethylene oxide products, isopropyl palmitic and myristate. Specific powdered stearins and cocoa butter substitutes are used in various formulations.The production and marketing of ingredients for this industry are natural growths of the developing fatty acid industry in Malaysia and nearby countries of southeast Asia.

Use of Mechanically Deboned and Manually Deboned Poultry Meat in Meat Emulsions: a Review

The increasing availability of mechanically deboned meats from under-utilized poultry parts (backs, necks, wings, turkey frames, spent layers) has presented the meat industry with a potentially valuable raw material for use in emulsion-type meat products. This review examines the various factors influencing emulsifying characteristics of poultry meats as they relate to potential ingredient usage in meat emulsions. In addition, composition and quality factors that can influence the usage of mechanically deboned poultry meats are examined. Some of the areas requiring further research have been identified.

On the Discrimination of Raw Materials for Use in Margarine by the Phytosteryl Acetate Test

Sterol contents of 23 commercial margarines sold in Japan were measured by the digitonin method as described in the International Dairy Federation Standard. The contents ranged from 0.080 to 0.296%. The phytosteryl acetate test established for the detection of foreign vegetable oil or fat in butterfat can be applied to the discrimination of raw materials used to margarine. Four commercial margarines were made from pure vegetable source, nine from animal source and the remaining ten were the mixture of vegetable and animal oil or fat.

The Sensitive Price Index

THE weekly sensitive price index, to which there has been frequent reference in both the Weekly Letters and this REVIEW, was designed as an aid in forecasting intermediate fluctuations in business.' The series selected, therefore, were those which were found to be most consistent in anticipating such intermediate movements during the years upon which the choice of prices was based (I923, I924, and I925) when compared with indexes of wholesale commodity prices and of the physical volume of production of basic commodities. A list of the series is given in the table on page 44. The constituents of the index are mainly raw materials for use in manufacture, and their prices are therefore responsive to industrial prospects. Furtfhermore, several of them are byproducts; the supply of such goods is relatively inelastic, and the price consequently especially dependent upon demand. Finally, the commodities as a whole are subject to wider influences than their small number would suggest, since most are important in international trade, and many are used in numerous industries. The index is an unweighted geometric mean of actual prices, relative to the average for I926 as base.2 The considerations governing the choice of such an average are quite different from those that are important in the construction of an index to measure purchasing power or to be used in studying the quantity theory of money. In the present case, the purpose directs attention to the timing and direction of changes, not to the general level of the index. The type of average follows from this fact and from the several assumptions that follow concerning the relationship between commercial fluctuations and prices. These assumptions are: first, that any given change in the conditions of demand and supply for any one of the commodities has an influence that is relative to the price of the commodity at the moment; and, second, that the various commodities are of equal value for the purpose of the index. The index has been computed weekly, and is designated as applying to the week ending Wednesday; the prices included are those datedwithin the week either prices for a given day or averages of daily prices for a seven-day period. The index for any month is obtained by averaging the weekly indexes for those weeks whose major part falls in the month in question. The computation of the weekly index is, of course, performed with the aid of logarithms; the logarithm of the base is subtracted from the average of the logarithms of the actual prices to obtain the logarithm of the index.3 The number of commodities used in the index is relatively small, so that there is at all times possibility of distortion resulting from extraordinary fluctuations in one of the constituents. For example, the exceptionally wide movements in the price of rubber (arising from causes peculiar to this particular commodity) have at times had considerable undesirable effect on the index. But it is probable that such temporary disturbances have at least during the period covered merely necessitated caution in the interpretation of the index, and not impaired its usefulness. The period for which the sensitive index is now available (I92I-3I) is sufficiently long to make fruitful some review of the success or failure of the index in accomplishing the purpose for which it was designed.4 From I923 through 1925 (the test period) its performance was, as is