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 significant...
Dietary copper requirements
Despite the known essentiality of copper in humans, dietary requirements are still uncertain. World-wide, a number of Dietary Reference Values are recommended for copper intake see Table 5.2 but the variability between them is indicative of the lack of consensus between advisory bodies. Making dietary recommendations, even of Estimated Average Requirements EAR , is difficult owing to a lack of adequate data. In the UK, the Department of Health considers the available data on human copper...
Conclusion
There has been considerable emotive and public health debate over the last two decades on the relative importance of meat in the diet of modern humans. Early dismissive arguments have more recently been revisited and challenged as a result of the continual progress and review of nutritional science. The early focus on fat as the predominant cause of western style diseases of affluence led, na vely, to meat being blamed for diet related problems. More recently, the focus on the diets of our...
I 1
Fig. 11.4 Mechanism of the Strecker degradation of amino acids. Below pH 3 and above pH 8 or at temperatures above 130 C caram lisation , 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...
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...
The effect of MAP on the nutritional quality of fresh fruits and vegetables
During the last few years many studies have demonstrated that fruit and vegetables are rich sources of micronutrients and dietary fibre. They also contain an immense variety of biologically active secondary metabolites that provide the plant with colour, flavour and sometimes antinutritional or toxic properties Johnson et al, 1994 . Among the most important classes of such substances are vitamin C, carotenoids, folates, flavonoids and more complex phenolics, saponins, phytosterols,...
References 6
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1 donelan A and dobson D 2001 , 'Vitamin retention in prepared meal services', Food Service Technol, 1, 123-4 2 Williams p 1996 , 'Vitamin retention in cook chill and cook hot-hold hospital food-services', Journal of the American Dietetic Assoc, 96, 490-8 3 ranesh m n 1999 , 'Food preservation by heat treatment', in Handbook of Food Preservation, R S Rahman ed , New York, Marcel Dekker, 95-172 4 skudder p J 1988 , 'Ohmic heating new alternative for aseptic processing of viscous foods', Food...
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ALPAS H, KALCHAYANAND N, BOZOGLU F, SIKES A, DUNNE P and RAY B 1999 , 'Variation in resistance to hydrostatic pressure among strains of food-borne pathogens', Appl Environ Microbiol, 65 9 , 4248-51 ANGSUPANICH K and ledward D A 1998 , 'Effects of high pressure on lipid oxidation in fish', in Isaacs N S ed , High Pressure Food Science, Bioscience and Chemistry, Cambridge, UK, The Royal Society of Chemistry, 284-7 BARBOSA-C NOVAS G V, POTHAKAMURY U R, PALOU E and SWANSON B G 1997 , 'High pressure...