Antioxidant content

Esterbauer et cil. (1992) have studied the in vitro effects of copper on LDL oxidation and have shown that there are three distinct stages in this process. In the first part of the reaction, the rate of oxidation is low and this period is often referred to as the lag phase the lag phase is apparently dependent on the endogenous antioxidant content of the LDL, the lipid hydroperoxide content of the LDL particle and the fatty acid composition. In the second or propagation phase of the reaction, the rate of oxidation is much faster and independent of the initial antioxidant status of the LDL molecule. Ultimately, the termination reactions predominate and suppress the peroxidation process. The extensive studies of Esterbauer et al. have demonstrated the relative importance of the endogenous antioxidants within the LDL molecule in protecting it from oxidative modification. 

Nielsen J H, Lund-Nielsen T and Skibsted L (2004), Higher antioxidant content in organic milk than in conventional milk due to feeding strategy , Newsletter from Danish Research Centre for Organic Farming, September, No. 3. 

Important intrinsic quality criteria currently determining the market potential of new apple cultivars are related to the sensory quality such as fruit firmness (crispness) and the sugar and acidity contents. On the other hand, the nutritional composition (e.g. the vitamin or antioxidant contents) is currently not used as a criterion in the choice of cultivars, neither in conventional nor in organic fruit production. The difference in the content of such components between fruit species is in most cases more relevant than between cultivars of the same species (e.g. vitamin C content of oranges versus apples). 

Markus F, Daood HG, Kapitany J and Biacs PA. 1999. Changes in die carotenoid and antioxidant content of spice red pepper (paprika) as a function of ripening and some technological factors. J Agric Food Chem 47 100-107. 

Howard LR and Hernandez-Brenes C. 1998. Antioxidant content and market quality of jalapeno pepper rings as affected by minimal processing and modified atmosphere packaging. J Food Qual 21 317-327. Hribar J, Plestenjal A, Vidrih R and Simcic M. 1994. Influence of CO2 shock treatment and ULO storage on apple quality. Acta Hort 368 634. 

With regard to chemical analysis, literature data may underestimate phytochemical antioxidant contents, because studies generally focus only on antioxidants extracted by aqueous-organic solvents without taking antioxidants linked to DF into account (P6rez-Jim6nez and Saura-Calixto 2005 Saura-Calixto and others 2007). 

Du Toit R, Volsteedt Y and Apostolides Z. 2001. Comparison of the antioxidant content of fruits, vegetables and teas measured as vitamin C equivalents. Toxicology 166(l-2) 63-69. 

Tsai HL, Chang SKC and Chang SJ. 2007. Antioxidant content and free radical scavenging ability of fresh red pummelo [Citrus grandis (L.) Osbeck] juice and freeze-dried products. J Agric Food Chem 55(8) 2867-2872. 

Several studies have reported that modified/controlled atmosphere packaging delayed senescence and microbial growth in fmits and vegetables (Ayala-Zavala and others 2007). On the other hand, it has been observed that the antioxidant content and bioactivity could vary depending on the kind of treated fmit and treatment (Ayala-Zavala and others 2005). 

Propyl gallate, BHA, BHT, TBHQ, THBP, 4-hydroxymethyl-2,6-di-ferf-butylphenol, thiodipropionic acid and dilauiylthiodipropionic acid may be used provided that the total antioxidant content does not exceed 200 mg kg"1 of the fat or oil content when used according to good manufacturing practice. Anoxomer may be used provided that the total antioxidant content does not exceed 5000 mg kg 1 of the fat or oil content of the food. 

Appearance, assay, and degradation products, preservative, and antioxidant content as applicable should be considered for all dosage forms. The microbial bioburden of sterile dosage forms must be controlled and tested in compliance with pharma-copeial and/or internal specifications. The microbial bioburden of nonsterile dosage forms should be controlled, with appropriate sampling and testing. 

Sridevi, Yenagi, N., and Basarkar, P. W. (2008). Antioxidant contents of whole grain cereals of north Karnataka. Karnataka J. Agric. Sci. 21,602-603. 

New methods for non-destructive quantitative analysis of additives based on MIR spectra and multivariate calibration have been presented [67, 68], One of the limitations in the determination of additive levels by MIR spectroscopy is encountered in the detection limit of this technique, which is usually above the low concentration of additive present, due to their heavy dilution in the polymer matrix. The samples are thin polymer films with small variations in thickness (due to errors in sample preparation). The differences in thickness cause a shift in spectra and if not eliminated or reduced they may produce non-reliable results. Methods for spectral normalisation become necessary. These methods were reviewed and compared by Karstang et al. [68]. MIR is more specific than UV but the antioxidant content may be too low to give a suitable spectrum [69]. However, this difficulty can be overcome by using an additive-free polymer in the reference beam [67, 68, 69, 70]. On the other hand, UV and MIR have been successfully applied to quantify additives in polymer extracts [71, 72, 66]. 

Homeostasis at the cellular and, especially, at the organismal level includes equilibrium between the formation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and reactions of antioxidants maintaining appropriate levels of ROS and minimizing their unspecific reactions with vital biomolecules. Understanding this aspect of homeostasis is the reason for interest in antioxidant levels in the body and the antioxidant content of food and beverages. 

Fig. 6. Principle of reductive assays. The indicator is reduced by a sample assuming that reductants = antioxidants, the result is a measure of the antioxidant content of the sample.

Daood, H.G, Tomoskozi-Farkas, R. and Kapitany, J. (2006) Antioxidant content of bio and conventional spice red pepper (Capsicum annuum L) as determined by HPLC. Acta Agronomica Hungarica 54(2), 133-140. 

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