Copper toxicity

Copper toxicity is rare because levels in food and water are generally low and because increased dietary intake results in decreased absorption and increased excretion.38 Cases of both acute and chronic poisoning have, however, been reported. Acute toxicity has been known to result from accidental or deliberate consumption of copper salts and, more commonly, from contamination of drinks by copper containers.6 A1957 report of contamination of cocktails stored for just two hours in a metal...

Relationship of structure to nutritional quality bioavailability

The overall content of a given nutrient in a food is not always a useful indicator of its nutritional value because not all of the nutrient present is absorbed. Nutritionists must concern themselves with understanding the proportion of an avail able nutrient that is digested, absorbed, and ultimately utilised. In the case of nutrients or phytochemicals, whose beneficial effects are directed towards inhibiting degenerative diseases, it is important to know whether or not the nutrient is reaching...

Effect of high pressure on vitamins

Many authors have reported that the vitamin content of fruit and vegetable products is not significantly affected by high pressure processing. According to Bignon (1996), a high pressure treatment can maintain vitamins C, A, Bj, B2, E and folic acid and the decrease of vitamin C in pressurised orange juice is negligible as compared to flash pasteurised juices during storage at 4 C for 40 days. Similar findings have been reported for red orange juice high pressure (200-500MPa 30 C 1min) did not...

Future trends

We have demonstrated that ohmic heating is a very unique thermal process. Ohmic heating is considered a 'minimal process' besides the 'HTST' process. Potential uses of ohmic heating include 15,47-50 2 Sterilisation and pasteurisation. However, as mentioned earlier, there has been only limited research quantifying the potential benefits of ohmic heating processes in terms of nutrition preservation. More research is needed to realize the advantages of ohmic heating and to promote the...

Vitamins and food product shelflife

As the tendency to include nutritional information on the labels of food products has increased, so have the liabilities of the manufacturers. For many, if not most, foods the inclusion of nutrition information is optional but any statements made on the label come under the force of law. A company making an inaccurate voluntary nutritional declaration can be subject to prosecution. Within a nutritional information statement, vitamins are the main category of declared nutrients where the...

Impact on health absorption and recommended intakes

Minerals function mainly in three ways in the body 1. As structural components, e.g. calcium, phosphate and magnesium in bones and teeth. 2. In organic combinations as physiologically important compounds, e.g. phosphorus in nucelotides, zinc in enzymes such as carbonic anhydrase, iodine in thyroid hormone. 3. In solution in body fluids to maintain pH, help conduct nerve impulses, control muscle contraction, e.g. sodium and potassium in blood and intra-cellular fluids. The macrominerals are...

Appendices

Appendix 21.1 Tentative list of universities actively involved in high pressure research in the last 10 years particularly in the field of bioscience, food science and chemistry Laboratory of biochemistry, Department Department of Agricultural Chemistry (Research Institute for Food Science) Institute for Chemical Reaction Science Department of Biological Science and Department of Chemical and Biological Environmental Science Faculty of Home Economics Biotechnology Research Centre Ochanomizu...

The microbial safety of MAP

Modified atmospheres containing CO2 are effective in extending the shelf life of many food products. However, one major concern is the inhibition of normal aerobic spoilage bacteria and the possible growth of psychrotrophic food pathogens, which may result in the food becoming unsafe for consumption before it appears to be organoleptically unacceptable. Most of the pathogenic bacteria can be inhibited by low temperatures (< 7 C). At these conditions, only psy-chrotrophic pathogens can...

The priorities for nutritional enhancement 841 For the developed world

Although it is known that the distribution and processing of food can lead to a significant loss in nutritional quality, there are few instances where present evidence suggests there is a need to change current practices. There is very little evidence for nutritional deficiencies. In those cases where public health authorities have thought there is a potential problem, food supplementation with nutrients is a commonly adopted policy. The use of nutritional supplements is widespread. Whilst the...

Copper distribution in the body

Copper distribution around the body appears to operate in two phases.60 In the first phase, copper ions are exported from enterocytes into the circulation. This is controlled by specific copper transporting proteins, including ATP7A, a P-type ATPase localised to the trans-Golgi network. It is also known as the Menkes protein MNK, because hereditary deficiency results in Menkes disease.99 Copper ions secreted from the intestinal mucosa are immediately bound to the high-affinity plasma proteins...

Meat and fish

Quick freezing is extensively used to preserve a wide range of raw and cooked meat and fish. Freezing and frozen storage does not significantly affect the nutritional value of meat and fish proteins. However, as pointed out above, on thawing frozen meat and fish substantial amounts of intra- and extra-cellular fluids and their associated water-soluble proteins and other nutrients may be lost ('drip-loss'). The volume of drip-loss on thawing of meat and fish is highly variable, usually of the...

Factors affecting vitamin stability

One of the very few attributes that the vitamins have in common is that none is completely stable in foods. The stability of the individual vitamins varies from the relatively stable, such as in the case of niacin, to the relatively unstable, such as vitamin B12. The factors that affect stability vary from vitamin to vitamin and the principal ones are summarised in Table 10.2. The most important of these factors are heat, moisture, oxygen, pH and light. The deterioration of vitamins can take...

Copper deficiency

Clinical copper deficiency is seen mainly in malnourished and recovering children, in premature babies, in patients receiving total parenteral nutrition (TPN) and as a consequence of malabsorption. Copper deficiency also occurs as the result of Menkes syndrome, a rare inherited defect of copper transport. Malnourished children are reported to be at particular risk of copper deficiency. A diet consisting exclusively or predominantly of cow's milk, with its poor bioavailability of copper,...

Mechanisms of copper absorption

Copper absorption in humans has been found to depend on a number of factors, of which the most important is probably dietary copper intake.6 The efficiency of copper absorption is regulated to maintain body copper status, with levels of uptake rising to 70 during periods of deficiency,63 and falling to 12 in high-copper diets.61 This modulation of absorption, which provides a means of adapting to changing dietary intake, appears to develop during childhood, with copper absorption in infants...

The principles of ohmic heating

Ohmic heating is a thermal process in which heat is internally generated by the passage of alternating electrical current (AC) through a body such as a food Fig. 19.1 A schematic diagram of an ohmic heating device. system that serves as an electrical resistance. Ohmic heating is alternatively called resistance heating or direct resistance heating. The principles of ohmic heating are very simple, and a schematic diagram of an ohmic heating device is shown in Fig. 19.1. During ohmic heating, AC...

Impact on key nutrients carbohydrates

Reducing sugars such as glucose and lactose participate in Maillard reactions, which will be discussed further in section 14.3. The shear forces during extrusion can also create reducing sugars from complex carbohydrates as well as from sucrose and other sugars. Sucrose losses of up to 20 were found in protein-enriched biscuits (Noguchi and Cheftel, 1983). While sucrose loss may affect product color and flavor, there is an opportunity to reduce the content of indigestible oligosaccharides that...

Consumer expectations and understanding of nutrition labelling

Of the many factors governing food choice, of which price is likely to be quite high on most people's lists, nutrition information may not figure strongly for many. But the enormous number and variety of food products available on the market today including imports of exotic foods and ingredients from all over the world, resulting from the increasing interest in ethnic dishes generated by long-haul travel and TV cooks, not to mention new ranges of products inspired by these developments, means...

The effect of ohmic heating on nutrient loss diffusion

Studies40,42 have shown that compared with conventional heating, ohmic heating enhanced diffusion of charged species between solid particles and the surrounding liquid, which could have some impact on loss of nutrients from solid particles to carrier liquid. This becomes undesirable only if the carrier liquid is not to be consumed together with the solid particles. Figure 19.3 shows that the transfer of betanin dye between beetroot and the surrounding fluid increases linearly with applied...

Relative glycaemic potency and glycaemicglucose equivalents

Control of postprandial glycaemia - the blood glucose response to food intake -is an increasingly important health issue. Diabetes mellitus, marked by an inability to control blood glucose levels, is increasing rapidly in many developed countries, in which an over-supply of high energy and highly digestible carbohydrate foods is coupled with predisposing factors, including physical inactivity, obesity, and inheritance.28 Many consumers need to be able to manage postprandial glycaemia by...

The principles of microwave heating

Microwave processing is simply heating by radiation (Kaatze, 1995). As such it is similar to infrared heating the energy transfer is by radiation and not by convection or conduction. However, there are significant differences in infrared heating the penetration of the radiation into the substance is marginal and the main portion is heated by conduction from the surface into the centre, in microwave processing microwaves penetrate throughout the volume of the substance and the 'heat-sources' are...

Watersoluble vitamins

The water-soluble vitamin group contains eight vitamins collectively known as the B-complex vitamins plus vitamin C (ascorbic acid). Thiamin is widely distributed in living tissues. In most animal products it occurs in a phosphorylated form, and in plant products it is predominantly in the non-phosphorylated form. Commercially it is available as either thiamin hydrochlo-ride or thiamin mononitrate. Both these salts have specific areas of application and their use depends on the product matrix...

Thermal processing

Livestock can be fed cereals or by-products from cereal processing without any thermal processing (cooking). In contrast, cereal-based foods intended for human consumption almost inevitably undergo some form of cooking. The cooking processes can be as simple as boiling the grain or its meal in water. Alternatively, they can be complex systems involving mixing with other ingredients to form a dough, followed by mechanical processing and subsequent cooking (e.g. baking, as in the case of bread)....

Other nutritional changes 1471 Antinutrients

Extrusion cooking also improves the nutritional quality of foods by destroying many natural toxins and antinutrients (Table 14.4). A dilemma exists as to whether it is desirable to remove these compounds. Enzyme inhibitors, hormonelike compounds, saponins and other compounds could impair growth and development in children, but these same compounds may offer protection against chronic diseases in adults. Allergens and mycotoxins are very resistant to thermal Table 14.4 Antinutrients and toxins...

Vitamins

Killeit (1994) reviewed vitamin retention in extruded foods. More research on the bioavailability of added and endogenous vitamins is needed, particularly in light of fortification programs for folate and other vitamins. Concerns of reduced vitamin levels prompt some manufacturers to apply vitamins post-extrusion as a spray. More recent research has focused on vitamin stability in feeds. Fat-coated ascorbic acid, menadione, pyridoxine and folic acid were retained better than were crystalline...

The effect of ohmic heating on nutrient loss thermal destruction

Since systematic research on ohmic heating has a much shorter history than has conventional heating, food scientists and technologists might look to microwave heating for information on nutrient changes. In general, many improvements in nutritional quality were found using microwaves (cooking in a minimum of water retained more K, vitamin B12, and vitamin C, and the absence of surface browning retained more amino acid availability, especially lysine), and microwave heating induces no...

Strategies for nutritional enhancement

There is no single approach to the improvement of the nutritional quality of plant foods since this is affected by a wide variety of factors. Amongst these are The application of traditional breeding methods to select for varieties with an increased level of the bioactive compound. A reduction in the content of antinutritional factors. The use of genetic manipulation to introduce new traits in plants. Improvements in handling, storage and food processing technologies. Each of these approaches...

Sources of further information and advice

For an extensive review of the effects of freezing on the chemical and physical properties of foods see Low temperature preservation of foods and living matter (1973), edited by Fennema OR, Powrie WD and Marth EH, published by Marcel Dekker, New York. For details of industry standards and procedures relating to frozen food see Recommendations for the Processing and Handling of Frozen Foods (1986), published by the International Institute of Refrigeration, Paris. For a description of the...

References

Advertising standards authority (1999), The British codes of advertising and sales promotion, www.asa.org.uk alldrick a j (1998), 'Functional foods, assuring quality', in Sadler, M J and Saltmarsh, M (eds.), Functional Foods - The Consumer, The Products, The Evidence, Cambridge, Royal Society of Chemistry, 135-42 alldrick a j (2001), 'Developing fibre-rich foods in the twenty-first century', in McCleary, B V and Prosky, L (eds.), Advanced Dietary Fibre Technology, Oxford, Blackwell Science,...

Melanoidins

The modifications of amino acids described in the preceding section take place also during either mild treatments or short duration treatments at high tempera tures, where the changing of food appearance is hardly perceptible. However, many processes usually dealing with the processing of vegetables, such as bread baking, roasting of coffee and nuts, and kiln drying of malt as well as roasting of meat require severe thermal treatments. In these cases the Maillard reaction is responsible for...

Carbohydrates and fats

For mono- and oligosaccharides, little direct degradation occurs at temperatures typical of UHT processing but there are several reactions that occur that may affect nutritional quality. Firstly, Maillard reactions may occur, depending on the composition of the food, i.e. the presence of reducing sugars and amino acids. This is covered in Chapter 11 and will not be further discussed here. It is interesting to note that one of the intermediate compounds formed during the reactions,...

Changes in frying oil 1221 Types of reaction

The oil is subject to three types of reaction during deep frying pyrolysis of oxidation products. Triacylglycerols in frying oil are hydrolysed by steam produced from water in the fried product when it is in contact with the hot frying oil. As the two reacting partners are not miscible, the reaction is relatively slow, resulting in the formation of diacylglycerols and free fatty acids. Diacylglycerols are more polar and therefore their contact with water vapour is better monoacylglycerols and...

Proteins

Two reviews of protein extrusion have been published (Camire, 1991 Areas, 1992). The effects of extrusion on protein nutrition have been studied extensively for animal feeds and for human weaning foods. Total protein changes very little during most extrusion operations. Changes in nutritional quality may be overlooked if only total nitrogen is assayed animal feeding studies or in vitro protein digestibility testing should be performed on products that are designed to provide significant amounts...

Synthesis and actions of 125OHD

The most biologically active form of calciferol is 1,25-OHD and its synthesis is tightly controlled (Loveridge, 2000). The kidney produces both dihydroxylated forms of vitamin D (1,25 and 24,25-OHD) the dominant form is determined by Fig. 3.2 Metabolism of vitamin D and the biological actions of 1,25 dihydroxyvitamin D (1,25-OHD) in raising blood calcium from bone resorption and or the intestinal absorption. The figure shows the stimulatory role of parathyroid hormone (PTH) on kidney synthesis...

H2nhccoohncn COOH

Aldoketose

Fig. 11.4 Mechanism of the Strecker degradation of amino acids. Below pH 3 and above pH 8 or at temperatures above 130 C (caramelisation), sugars will degrade in the absence of amines (Ledl and Schleicher, 1990). Ring opening followed by 1, 2 or 2, 3-enolisation are crucial steps in ARP transformation and are followed by dehydration and fragmentation with the formation of many very reactive dicarbonyl fragments. This complex of reactions is considered the intermediate stage of the MR. Maillard...

Functions and requirements

TDP is the co-enzyme for pyruvate dehydrogenase (EC 1.2.4.1) and trans-ketolase (EC 2.2.1.1.) in carbohydrate metabolism, a-ketoglutarate dehydrogenase (EC1.2.4.2.) in the citric acid cycle and branched chain keto-acid dehydrogenase (EC 1.2.4.4.) in the metabolism of branched chain amino acids. 2. TTP acts in nerves (and maybe muscles) to activate a chloride ion channel (Bender, 1999). In addition, TTP may play a fundamental role in the control of conductance of axonal membranes as well as in...

Effect of high pressure on lipids

The most interesting effect of high pressure on lipids in foods is the influence on the solid-liquid phase transition, e.g. a reversible shift of 16 C per 100 MPa for milk fat, coconut fat and lard (Buchheim et al, 1999). With respect to the nutritional value of lipids, the effect of high pressure on lipid oxidation and hydrolysis in food products is of importance. Lipid oxidation is a major cause of food quality deterioration, impairing both flavour and nutritional values (related to health...

Transformations not involving sugars crosslinked amino acids

Another kind of transformation of the side chains of protein-bound amino acids induced by thermal treatments of foods, particularly in basic conditions, is the formation of cross-linked amino acids. A dehydroalanine residue may be formed through elimination of a leaving group from protein-bound serine, O-phosphorylserine, O-glycosylserine, or cystine, and may undergo Michael addition by another nucleophilic amino acid residue (Fig. 11.12). For example the e-amino group of lysine may react to...

Introduction

The most common dietary problems in developed countries are due mainly to over nutrition. The incidence of overweight, obesity and adult onset-diabetes is increasing steadily. Cancer is now the most common cause of death in many developed countries. The most common cancers are breast, lung, bowel and prostate, which are virtually absent in some developing countries. However, even in our affluent society, we also see signs of nutritional inadequacies. For instance, in the UK nearly half of...

Safety of vitamin A and bcarotene 371 Safety of retinol

Symptoms of hypervitaminosis A may occur in the skin, nervous system, musculoskeletal, circulatory systems or in internal organs. Toxicity varies with the dose, body mass, age, sex, disease conditions, concurrent drugs being taken and environmental chemical exposure (Blomhoff, 2001). Toxicity is rare from natural diets, the exception is from high intakes of liver (3-5mg 100g) (Northrop-Clewes, 2001b). Fortified foods are used in industrialised countries and can be consumed excessively (e.g....

Faecal bulking index and wheat bran equivalents

Faecal bulking capacity is an important property of foods because bulk in the large bowel has a crucial role in large bowel function and health (Table 7.6). The direct relationship between faecal bulk and 'regularity' is of concern to a large Table 7.6 Putative links between properties and effects of bulk in the large intestine Toxin removal, colonic exposure reduced, decreased transit time. Replenishment of substrates for fermentation - decreased colon cancer Less protein putrefaction to...

Vitamin K status and health 3211 Adults

Vitamin K deficiency in adults leading to clinical bleeding is almost unheard of, except as a consequence of hepato-intestinal disorders which disturb the absorption or utilisation of the vitamin. Use of warfarin or other anti-coagulant drugs, i.e. vitamin K antagonists, in the management of thromboembolic disease, reduces circulating concentrations of vitamin K-dependent clotting factors. The anticoagulants inhibit the biosynthesis of prothrombin and other vitamin K-dependent factors in the...

Nutritional enhancement versus food fortification

The importance of enhancing the levels of a natural protective constituent in plant foods is well illustrated in the case of the folates. There is a good chance that folate status even in affluent countries is not optimal.25,26 The most important sources of folates in the diet are liver, products derived from yeast, eggs, green vegetables, legumes and certain fruits. Plant foods (vegetables, fruits and potatoes) are by far the single largest contributor to the overall folate intake of...

Meat and micronutrients 9111 Iron in meat

Iron deficiency (Schrimshaw, 1991) and iron deficiency anaemia (Walker, 1998) remain the most common nutritional disorders in the world today. Iron deficiency is the only widespread nutrient deficiency occurring in both developed and developing countries. Iron deficiency affects between 20 and 50 of the world's population (Beard and Stoltzfus, 2001). There are many causes of iron deficiency, including hook worm infestation, low iron intakes, low bioavailability of dietary iron and increased...

Effect of high pressure on other healthrelated food compounds

Synthetic dipeptide aspartame (aspartylphenylalanyl methyl ester) is widely used as a sweetener in light (low calorie) foods and diets for diabetics. The effect of high pressure on aspartame stability has been reported by Butz and co-workers (1997). Aspartame (0.5 g L corresponding to the concentration in commercial diet cola and chocolate milk) in full cream milk (pH 6.8) lost almost 50 of active substances after pressure treatment at 600 MPa and 60 C for 3 minutes while the non-sweet...