How do we best model the role of antioxidants in foods

1. How do we best model the role of antioxidants in foods Angela Chen

2. What’s lipid oxidation and mechanism of lipid oxidation • The lipid oxidation which involves autoxidation of unsaturated fatty acid • Two principals of oxidation contributed to food deterioration; autoxidation of unsaturated fatty acids and enzyme catalyzed deterioration. • Product from autoxidation, free radical. • Mechanism of lipid oxidation : initiation, propagation and termination.

3. The problems from lipid oxidation • Development of rancidity, loss of color, texture since increase use of polyunsaturated oil( susceptible to oxidation ) • Also, loss the nutritional quality and safety by formation of secondary products. • A study conducted that rats consumed with highly oxidation fat that rendered decrease appetite, inhibit of growth, and swell of liver and further induce cancer. • Limit the shelf life

4. How to control lipid oxidation • Adding antioxidants to that delay or prevent the deterioration of foods by oxidative mechanisms.( to maintain quality and shelf life) • Antioxidants work to inhibit free radical oxidation by either reacting with peroxyl radicals or with alkoxylradicals in lipid peroxidation • Antioxidants can interrupt lipid autoxidation by interfering with either the chain propagation or the decomposition processes. 

5. Method of antioxidant • According to mechanism of action that chemical compound, antioxidants can be classified into two types: • Primary antioxidants –chain breaking antioxidants it can react with peroxy radical as well as convert into stable products which are not react rapidly with unsaturated fatty acid( Wilailuket al, 2007). • Secondary antioxidants- reduce the rate of oxidation such as, chelator,

6. Role of antioxidants in inhibiting lipid peroxidation ( chem. reactivity of antioxidants ) • 1. free radical scavenges (Pokorny, 2007) would slow the rate of autoxidation • 2. metal chelator(Frankel, 2005; Pokorny, 2007) that inhibits decomposition of hydroperoxide • 3. singlet oxygen quencher -physical quenching : energy transfer -chemical quenching : break down / oxidation quench • 4. Synergist that inhibit of lipid oxidation α-tocopheroland ascorbic acid in autoxidation (Liebler,1993)

7. The effectiveness of antioxidant activity and Interacting components ( physical factors ) • Interfacial phenomena • Antioxidant location in the emulsion is critical. • The antioxidant partitioning behavior between diff. pahse • The interface membrane, and type of surface activity also play a role. • The stability of colloidal, lipid bearing food is affected by surface active substance and interfacial interaction. • Frankel et al, (1996), antioxidants in lipid foods and their impact on food quality.

8. The effectiveness of antioxidant activity and Interacting components ( environment factors ) • Frank et al claims that high pH lower the lipid oxidation • Huang et al (1997 ) conducted that the pH level would affected their distribution, hydrogen donating ability, & relative oxidative stability in diff. phase.

9. The effectiveness of antioxidant activity and Interacting components ( others factors ) • Antioxidants are most effective in muscle food, which can reduce the rate of oxidation (Erickson, 2002). • In muscle food, oxidative most occurs in water enviro. , thus hydrophilic antioxidants works better than lipophilic antioxidants. ( Decker, 1998) • During the processing some factor alter the oxidation, Laguerre et al (2007) conducted that antioxidants efficiency seems have inversely proportional to the heat. • Antioxidant effectiveness is depend on the reaction of antioxidants, ex: heme

10. Conclusion • The effectiveness of antioxidants depends on several factors such as the polarity of the antioxidants, lipid substrate, pH, and temperature, the presence of metal ions, and the physical properties of the food

11. Reference • Kamal Eldin, A. (2006), Effective of fatty acids and tocopherol on the oxidative stability of vegetable oil. Eur. J. Lipid Sci.Technol. 58: 1051-1061 • Frankel, E.N.& Meyer, A.S, (2002) Review the problem of using one dimensional methods to evaluate multifunctional food and biological antioxidants. J.Sci Food Agri. 80:1925-1941. • Frankel, E.N (1996) Antioxidants in lipid foods and their impact on food quality.(1996). Food Chemistry . 57: 51-55. • Niki, E. & Noguchi, N.(2000)critical review evaluation of antioxidants capacity. What capacity is being measured by which methos? Life. 50:323-329. • Decker, E.A, Warner, K.,Richards.M.P, Shahidi, F.(2005).J Agri Food Chem.53: 4303-4310. • Sun, Y.E, Wang, W.D., Chen, H.W., Li, C.(2011) Autoxidation of unsaturated lipids in food emulsion. Critical Review in food science and nutrition. 51: 453-466. • Laguerre, M., Lecomte, J. Villeneuve, P.(2007) evaluation of the ability of antioxidants to counteract lipid oxidation: existing methods, new trends and challenge. Progress in lipid research. 46: 244-282. • Chaiyasit, W.Elisa, R.J., Mcclements, D.J., Decker, E.A.(2007). Role of physical structures in bulk oils on lipid oxidation. . Critical Review in food science and nutrition. 47: 299-317.