Relationships between Free Radical Scavenging and Antioxidant Activity in Foods

Abstract

Numerous attempts have been made to relate the free radical scavenging capacity of compounds to their antioxidant activity in foods even though antioxidant activity is dependent on both physical and chemical properties. The objective of this study was to compare the free radical scavenging activity of various compounds to their ability to inhibit lipid oxidation in foods. The order of free radical scavenging activity of polar compounds was ferulic acid > coumaric acid > propyl gallate > gallic acid > ascorbic acid as determined by a modified oxygen radical absorbance capacity, while the order of nonpolar compounds was rosmarinic acid > butylated hydroxytoluene >or= tert-butylhydroquinone (TBHQ) > alpha-tocopherol as determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Of these compounds, only propyl gallate and TBHQ were found to inhibit lipid oxidation in cooked ground beef as determined by thiobarbituric acid reactive substances, while only propyl gallate, TBHQ, gallic acid, and rosmarinic acid inhibited lipid oxidation in an oil-in-water emulsion as determined by lipid hydroperoxides and headspace hexanal. These data indicate that the free radical scavenging assays tested have limited value in predicting the antioxidant activity in complex foods.

Determination of the antioxidant capacity, total phenolic and flavonoid contents of seeds from three commercial varieties of culinary dates

“…The seeds of Deglet Nour and Khoaut Allig had similar values of 27698 and 26905 µmol TE 100 g −1 of DSP on FW basis, whereas significantly lower amounts (P ≤ 0.05) were detected in Zahidi (12540 µmol TE 100 g −1 of DSP on For future studies, the use of more than one single approach for TAC determination is recommended in order to take into account the diverse mechanisms of action of antioxidants (Huang et al, 2005;Capitani et al, 2009;Dudonne et al, 2009;Tabart et al, 2012). On the other hand, there are still controversies over the significance of current in vitro techniques in predicting the in vivo effects of antioxidant compounds (Serrano, Goni, & Saura-Calixto, 2007) and their functionality in preventing or delaying oxidation in foods (Fernandez-Panchon et al, 2008;Alamed, Chaiyasit, McClements, & Decker, 2009). In terms of the physiological effects of their consumption, in vitro studies should be supported by in vivo clinical tests aiming to investigate specific healthpromoting activities.…”

“…In terms of the physiological effects of their consumption, in vitro studies should be supported by in vivo clinical tests aiming to investigate specific healthpromoting activities. Moreover, in terms of their active properties further tests on actual food systems should be carried out looking at the ability of date seed extracts to counteract the formation of reactive species using appropriate techniques such as thiobarbituric acid reactive substances, lipid hydroperoxides and headspace hexanal analysis (Alamed et al, 2009). In the course of the study gallic acid was also investigated as potential alternative to Trolox.…”

Hurdles in Predicting Antioxidant Efficacy in Oil-in-water emulsions

“…However, free radical scavenging activity is not always a predictor of the 98 efficacy of an antioxidant in foods. For example, Alamed and coworkers reported that ascorbic 99 acid was twice as effective at scavenging peroxyl radicals as propyl gallate in the oxygen radical 100 absorbance capacity assay while propyl gallate was a much better antioxidant in oil-in-water 101 emulsions (Alamed et al, 2009). This highlights the issue of antioxidant location in a food and 102 its ability to inhibit lipid oxidation.…”

Natural antioxidants as stabilizers for polymers

“…Lipid oxidation leads to unsavory odor, color, taste and altered texture of food products, which can be hindered by the proper application of antioxidants [52]. Carotenes are usually applied as natural yellow, orange or red colorants in various foods like cakes, sauces, marinades, spice blends, beverages and dairy products [53].…”

“…As we discussed above, natural phenolic antioxidants inhibit the peroxidation of lipids, which is a major concern in the food industry [52]. Different types of flavonoids [91], tocopherols and tocotrienols [92] are applied as stabilizers in food, while curcumin is a natural colorant with additional stabilizing effect [93].…”