Autoxidation-Initiated Reactions in Foods

Karel, Marcus

doi:10.1016/b978-0-12-591350-8.50026-7

Cited by 21 publications

(15 citation statements)

References 46 publications

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“…Isto confirma as observações de outros autores (BROCKMANN & ACKER, 1977b;GOPALAKRISHNA & PRABHAKAR, 1983;KAREL & YONG, 1981), que no processo oxidativo atuam dois tipos de reações: primárias, diretamente sobre os lipídeos e, secundárias, que transformam os produtos das reações primárias. As secundárias são mais importantes no que se refere à aceitação pelos consumidores.…”

Section: Resultsunclassified

Umidade relativa de equilibrio e oxidação de lipídeos em farinhas de castanha do Pará, de macadâmia e de soja

Prado-Filho

1994

Sci. agric. (Piracicaba, Braz.)

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RESUMO -Foi estudada a oxidação de lipídeos adicionados a farinhas de castanha do Pará (Bertholleta excelsa), de macadâmia (Macadâmia integrifolia) e de soja (Glycine max) equilibradas nas atividades de água (Aa) 0,51; 0,57; 0,67; 0,75; 0,79 e 0,81, a 35°C. O substrato utilizado para quantificar tanto a oxidação autocatalítica como a oxidação enzímica foi o óleo de soja na proporção de 20% (p:p). Dois mecanismos de oxidação de lipídeos concorrem pelo substrato nas condições estudadas. A baixos valores de Aa -de 0,51 a 0,75 -o mecanismo mais eficiente é a autoxidação devida à maior exposição do substrato ao oxigênio e à menor mobilidade dos reagentes -enzima e lipídeo -nas reações de natureza enzímica. Em valores de Aa maiores -0,79 e 0,81 -predomina a oxidação enzímica, e atua a proteção do substrato pela água, frente à ação do oxigênio. O índice de peróxido medido no transcurso de 6 dias apresenta máximos e mínimos devidos a reações secundárias atuando sobre produtos das reações primárias. Descritores : oxidação autocatalítica e enzímica, lipídeos, farinha, castanha do Pará, macadâmia, soja EQUILIBRIUM RELATIVE HUMIDITY AND LIPID OXIDATION IN BRAZIL-NUT, MACADAMIA NUT AND SOYBEAN SEED FLOURSABSTRACT: Lipid oxidation was studied on the flour of Brazil-nut (Bertolleta excelsa), macadâmia nut (Macadamia integrifoliá) and soybean seed (Glycine max), in enviroments with controlled water activity (Aw) values of 0.51; 0.57; 0.67; 0.75; 0.79 and 0.81 at 35°C. Every 24 hours during 6 days the peroxide value was determined for each Aw in flour with enzyme inactivation (110°C, 2 hours) as well as in flour without inactivation. At low Aw values (up to 0.75) the oxidation by oxigen is the most effective mechanism of deterioration of the lipids. At higher water activity values (0.79 and 0.81) the protective effect of the humidity upon the lipids and the greater mobility of the reagents make the activity of the lipoxigenase the most important mechanism of lipid deterioration.

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Section: Resultsunclassified

Umidade relativa de equilibrio e oxidação de lipídeos em farinhas de castanha do Pará, de macadâmia e de soja

Prado-Filho

1994

Sci. agric. (Piracicaba, Braz.)

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“…Most of the published studies were conducted on the effects of dehydration on sensory qualities or some physical and chemical changes such as texture, color, flavor, aroma, taste of foodstuff (Drouzos & Schubert, 1996;Garcia, Leal, & Rolz, 1988;Karel & Young, 1981;Koller & Raghavan, 1995;Nykänen & Nykänen, 1987;Paakkö nen, Malsmten, & Hyvö nen, 1989;Prabhanjan, Ramaswamy, & Raghavan, 1995;Sinesio, Moneta, Spatora, & Quaglia, 1995;Venskutonis, Poll, & Larsen, 1996;Yü ksel, Luning, Vuurst-de Vries, Wichers, & Leguijt, 1995). But there are only a few studies on effects of drying processes on the mineral content of foods.…”

Section: Introductionmentioning

confidence: 98%

Effect of drying methods on the mineral content of basil (Ocimum basilicum L.)

Özcan¹,

Arslan²,

Ünver³

2005

Journal of Food Engineering

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“…Addition of water beyond boundary of mono-layers and multilayer zones results in an increase in rates of oxidation. Karel and Yong [61] have suggested that water added in this region of the isotherm may accelerate oxidation by increasing the solubility of oxygen and by allowing macromolecules to swell, thereby exposing more catalytic sites. In dried and fat-containing foods with very low moisture contents (a w < 0.1) oxidation proceeds very rapidly.…”

Section: Reaction Of Water With Other Components Of Foodmentioning

confidence: 98%

“…[2] At water activities more than 0.80, the added water may retard rates of oxidation, and dilution of catalysts reduces their effectiveness. [2,61] The rates of non-enzymatic browning (Maillard reaction) are greatest in foods with an intermediate moisture contents (bakery products, roasted nuts, toasted breakfast cereals, and roller-dried milk powder). [2] Undesirable Maillard reaction can be inhibited by decreasing moisture to a very low level or by increasing dilution (if the food is in liquid state).…”

Section: Reaction Of Water With Other Components Of Foodmentioning

confidence: 99%

Use of Water Properties in Food Technology: A Global View

Kasaai

2014

International Journal of Food Properties

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Water is a major component of drinking water, beverages, and most foodstuffs. In this study, an effort has been made to employ selected properties of water for: (1) evaluation of interactions of water with other food components; (2) discussion on the effects of water properties on food and beverage products; (3) applications of water properties in food technology; and (4) comparison of water properties with corresponding properties of similar substances. This study provides the following major conclusions: (i) unusual properties of water are mostly due to its high permanent dipole moment, partial ionic character of O-H covalent bonds, and extensive hydrogen bonds; (ii) different properties of many foodstuffs are strongly related to various properties of water; (iii) the properties of food products change depending on water availability and temperature; (iv) preparation of drinking water is a prerequisite for production of any safe drinks and foodstuffs; (v) water contributes important roles in quality, flavor, and shelf-life of foods; and (vi) water is used in food industries as a fluid for heat transfer; as a medium for temperature moderation in food processing; as a solvent for sugars, salts, water-soluble vitamins, and acids; as a dispersing agent for hydrophilic food components; as a dispersed phase for emulsified products; or as a reactant for several reactions in food processing.

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Autoxidation-Initiated Reactions in Foods

Cited by 21 publications

References 46 publications

Umidade relativa de equilibrio e oxidação de lipídeos em farinhas de castanha do Pará, de macadâmia e de soja

Umidade relativa de equilibrio e oxidação de lipídeos em farinhas de castanha do Pará, de macadâmia e de soja

Effect of drying methods on the mineral content of basil (Ocimum basilicum L.)

Use of Water Properties in Food Technology: A Global View

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