Degree Of Heat Treatment Research Articles

Degradation of water-soluble fibre polysaccharides in carrots after different types of processing

The molecular weight distribution and the viscosity of water-soluble polysaccharides isolated from carrots were investigated after different types of heat-treatment, commonly used when preparing food. The materials studied were blanched, boiled, microwaved and canned. Freezing, without any heat-treatment, was used as a reference process. The water soluble polysaccharides were isolated using two different procedures, i.e. before and after enzymic digestion of protein and starch. Only minor differences in molecular weight distribution between frozen and blanched materials could be detected by gel-filtration. However, when the carrots were further heat-treated, i.e. boiled, microwaved and canned, there was an increase in both the high molecular and the low molecular weight fractions of soluble polysaccharides (especially pectic substances) isolated after digestion of protein and starch. This indicated a solubilization of originally isoluble material, as well as a degradation of the soluble high molecular weight material. On the other hand, in the polysaccharide fraction isolated directly, i.e. without any degradation of protein and starch, there was an increase only in the low molecular weight fraction and only when the materials were microwaved and canned. The viscosity of polysaccharides isolated without degradation of protein and starch could be correlated with the extent of degradation of the polysaccharides, and thus also with the degree of heat-treatment, in the following order: freezing, blanching, boiling, and canning. However, the viscosity of soluble fibre isolated after degradation of protein and starch was similar and low for all materials studied.

Effect of processing and storage on rheological properties of fortified milk and curd systems

SummaryFortified milk systems were prepared by blending pasteurized standardized milk with skim milk powder, peanut flour or peanut protein isolate to 15, 18, 20, and 23% total solids followed by processing at 60°C and 80°C for 30min and storage at 4°C for 24h. Curds were prepared by the lactic fermentation of the processed milk systems. The rheological properties showed that all the systems exhibited pseudoplastic flow. The flow became less Newtonian with increasing total solids, heat treatment, and storage. Curd obtained from the fortified milk processed at 80°C showed increased yield stress and curd strength with the increasing concentration. Degree of heat treatment, total solids content and storage were shown to have a pronounced effect on the apparent viscosity, consistency index, and yield stress of the fortified milk systems.

The surface topography of non-shear treated pitch and PAN carbon fibers as viewed by the STM

The atomic structure and roughness on the surface of a carbon fiber have a great effect on the degree of bonding of that fiber in a carbon fiber composite. Although there have been many studies on the bulk structure of these fibers, this is the first study dealing with the atomic surface structure of several carbon fibers. With the advent of the scanning tunneling microscope (STM), it is now possible to study both the roughness and structure of these fibers on the atomic scale. Type II PAN based fibers were found to have a rougher surface than type II pitch-based fibers. Similar to what has been observed in the interior of pitch fibers, the percentage of graphitic structure on the surface increased with the degree of heat treatment and with the modulus of the fiber.

Nondestructive testing using electromagnetic instrumentation

Mechanical, structural and geometrical properties of metals, such as the presence of defects, hardness, degree of heat treatment, and dimensions can often be tested nondestructively by electromagnetic methods. These methods include the use of eddy currents and magnetic particles, which are particularly effective for locating and sizing surface and subsurface defects, and the application of magnetic hysteresis. The established techniques and some of their more recent developments are described.

Vegetable proteins in cooked and/or fermented sausages.

AbstractMan is the only animal cooking meat for food. Various arts and degrees of heat treatment were devised by the early egyptians, Greeks and Romans; this was often combined with a surprisingly high degree of sophisticated fermentation. From initial meat searing in the Iron Age to modern barbecue pits, electronic conveyers, rotomats, the introduction of steam and controlled smoking, development of curing salts, and the controlled production of meat itself, man created new meat processing technology designed to improve flavor, texture, shelflife, availability, acceptability and economy, thus satisfying the crucial demands of both the consumer and processor. During this time man also discovered the disadvantage of heat, namely the inevitable loss of volume, changes in texture, color and palatability. At the same time, he started using various tubers, cereals and salts to minimize cooking losses. These functional comminuted meat product ingredients, today known as binders and fillers, have traditionally been locally available. They include potatoes, cereals, milk derivatives, hydrocolloids and vegetable proteins. It is estimated that 17,000 tons of various soy proteins were used in 1977 in Europe alone in heat‐treated and fermented meat products. Since sausages, fermented and hard salamis and similar ready‐to‐eat comminuted meat products are an important segment of European convenience meat consumption, this paper concentrates on the technological, nutritional and economical impacts of soy proteins on these products. While in heat‐treated meats bacteriological growth is not desired, it is a regulation factor in the production of fermented sausages. In both types of products, soy proteins in their present form as isolates, concentrates, textured, various grits and flours, as well as spun or structured, play an important role in providing the consumer with appealing, nutritional products at acceptable prices. Examples of applications of soy proteins are discussed.

The effects of heat treatment, UV and gamma radiation on some beetroot pigments

The dominating red and yellow pigments from beetroot separated by paper electrophoresis, were exposed to various degrees of heat treatment, UV- and gamma irradiation. The present investigations indicate that under the given conditions, the isolated beetroot pigments are not sufficiently resistant to the physical treatments that may be expected during pasteurization of food products by heat or ionizing radiation. The pigment solutions had relatively greater absorbante in the lower region of their visible spectra after UV-light exposure, but the solutions lost some of their colour, and spectral characteristics.

Soy flour and grits for use in food products.

AbstractProcessing alternatives enable the soybean processor to manufacture soy flour products which vary in fat content, granulation and degree of heat treatment. By controlling these variables, the processor is able to regulate the nutritional value and functional properties of these products. The application of soy flour products is dependent upon their functional properties, nutritional value and low cost. Currently, the major markets for soy flour and grits are in pet foods and animal feeds, cereal based foods and ingredients, meat based foods, and as a substrate for refined protein products such as the textured vegetable proteins, soy protein concentrates, isolates and hydrolysates. These soy protein products are generally marketed as functional and nutritional substitutes for meat, milk and egg protein. For example, soy flour is a functional replacement for milk in many cereal‐based foods, e.g., bread, and also enhances the nutritional value of the cereal protein by supplying lysine to the formulation. The United States government has pioneered the development and marketing of protein‐enriched, cereal‐based foods designed to combat worldwide starvation. The government has directly supported the research and development of corn and wheat‐based food substrates supplemented with soy flour, and has purchased over one billion pounds of these products since 1966 for worldwide distribution.

The sorption of sulphur dioxide on silica gel

Adsorption isotherms of sulphur dioxide on silica xerogels have been obtained for the range 263–323°K. High purity xerogels were used after various degrees of heat treatment at 240, 500, 600, 650, 700, 900, and 1100°. These materials were characterised by low-temperature nitrogen adsorption and by measurement of the density by immersion in mercury. Comparative isotherms were measured at 263°K on commercial silica gels of widely different surface characteristics. Heats of adsorption (qst) were determined from isosters for the monolayer region (θ= 0–0·85). The qst values show a steady decrease with increasing surface coverage from 9·3 to 7·8 kcal. mole–1(240° xerogel). The sorption process is discussed in terms of a physical model.

The effect of heat treatment in the processing of groundnut meal on the value of the protein for ruminants with some additional experiments on copra

1. Groundnut meals subjected to different degrees of heat treatment during manufacture were fed to lactating goats on nitrogen-balance experiment. The ‘toasted’ groundnut meal was more effective than undenatured or air-dried meals in promoting nitrogen retention.2. The heat treatment of the groundnut meals did not influence the digestibility of the protein.3. The groundnut meals were typed by determining their salt-peptizability giving values ranging from 44% for the ‘toasted’ meal to 80% for the air-dried meal.

Mustard seed processing: Simple methods for following heat damage to protein meals

AbstractProcessed mustard seed contains a considerably higher content of reducing sugar than other oilseeds. During processing, the natural reducing sugar is supplmented with glucose released by enzyme hydrolysis of the thioglucoside, and this total content reaches a value of more than 3% of the defatted mustard meal. This quantity of reducing sugar in mustard seed is three times more than that in soybean meal. Consequently, the browning reaction, which degrades protein, presents a greater problem in processing oilseeds containing thioglucosides than oilseeds free of thioglucosides. In developing the processing of mustard seed, the degree of heat treatment given the protein meals had to be determined. Several indirect methods were developed for following the effects of heat treatment on protein quality. Nitrogen solubility index, optical density of aqueous extracts, and reducing sugar content correlated well with degradation of heat‐labile amino acids, such as lysine, arginine, and histidine, and gave an index of protein quality.

The growth of aerobic spore-forming bacilli in sterilized milk

SummaryThe sterilization of homogenized milk at 115·5°C for 15 min in bottles having a partial vacuum in the headspace produced conditions inhibitory to the growth from very small numbers of spores ofBacillus subtilis, B. licheniformis, B. cereusandB. breviswhen compared with growth in the same milk sterilized in open bottles.B. circulansdiffered from the other strains tested in showing greater inhibition in milk sterilized in open bottles than in milk sterilized under partial vacuum.The extent of the inhibition became less as the size of the inoculum was increased. It became less also as the temperature of incubation approached the optimum growth temperature of the bacillus, and was influenced by the strain of the bacillus and the source of the milk but not by the degree of heat treatment within the range 107–117·5°C for 15 min. Inhibition was manifested by a prolongation of the lag phase, and in addition with some strains inhibition of spore germination could be demonstrated.Spore formation following vegetative growth occurred more readily in milk sterilized in open than in evacuated bottles.Milks sterilized under partial vacuum frequently failed to show any growth from small inocula in 30 days at 22°C although growth occurred readily in milk sterilized in open bottles.

The photometric determination of the hemagglutinating activity of soyin and crude soybean extracts

A photometric procedure for measuring the hemagglutinating activity of soyin and crude soybean extracts is described. This method is based on the observation that rabbit erythrocytes sediment at a rate which is proportional to the concentration of the hemagglutinin. Hemagglutinating activity is calculated from absorbance measurements of the suspension of unsedimented cells after a given time. This technique was found to have potential value for predicting the nutritive value of soybean meals subjected to various degrees of heat treatment.

ALUMINUM 75S

Abstract ALUMINUM 75S is an ultra-strength aluminum alloy exhibiting exceptional mechanical properties, workability, and response to various degrees of heat treatment and refrigeration. It is suitable for highly stressed primary structures. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-5. Producer or source: Aluminum Company of America.