Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: the oxygen radical absorbance capacity (ORAC) assay, the Folin-Ciocalteu method, and possibly the Trolox equivalent antioxidant capacity (TEAC) assay. ORAC represent a hydrogen atom transfer (HAT) reaction mechanism, which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity, which has normally been expressed as phenolic contents. The TEAC assay represents a second ET-based method. Other assays may need to be considered in the future as more is learned about some of the other radical sources and their importance to human biology.

https://faculty.missouri.edu/~glaserr/3700s14/Antioxidant-Capacity_jf0502698.pdf

Standardized Methods for the Determination of Antioxidant Capacity and Phenolics in Foods and Dietary Supplements

https://aggie-horticulture.tamu.edu/faculty/cisneros/Papers/Thaipong_2006.pdf

Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts

Phenolic compounds in plants and agri-industrial by-products: Antioxidant activity, occurrence, and potential uses

This publication is based on studies carried out from August 2010 to January 2011 by The Swedish Institute for Food and Biotechnology (SIK) on request from the FAO. The two studies on global food losses (one for high/medium-income countries and one for low income countries) have been carried out to serve as a basis for the international congress Save Food!, 16-17 May 2011, at the international packaging industry fair Interpack2011 in Dusseldorf, Germany.
The study highlights the losses occurring along the entire food chain, and makes assessments of their magnitude. Further, it identifies causes of food losses and possible ways of preventing them. The results suggest that roughly one-third of food produced for human consumption is lost or wasted globally, which amounts to about 1.3 billion tons per year. This inevitably also means that huge amounts of the resources used in food production are used in vain, and that the greenhouse gas emissions caused by production of food that gets lost or wasted are also emissions in vain.

Global food losses and food waste: extent, causes and prevention.

Food waste in the global food supply chain is reviewed in relation to the prospects for feeding a population of nine billion by 2050. Different definitions of food waste with respect to the complexities of food supply chains (FSCs)are discussed. An international literature review found a dearth of data on food waste and estimates varied widely; those for post-harvest losses of grain in developing countries might be overestimated. As much of the post-harvest loss data for developing countries was collected over 30 years ago, current global losses cannot be quantified. A significant gap exists in the understanding of the food waste implications of the rapid development of ‘BRIC’ economies. The limited data suggest that losses are much higher at the immediate post-harvest stages in developing countries and higher for perishable foods across industrialized and developing economies alike. For affluent economies, post-consumer food waste accounts for the greatest overall losses. To supplement the fragmentary picture and to gain a forward view, interviews were conducted with international FSC experts. The analyses highlighted the scale of the problem, the scope for improved system efficiencies and the challenges of affecting behavioural change to reduce post-consumer waste in affluent populations.

/pdf/food-waste-within-food-supply-chains-quantification-and-344f4n2oz2.pdf

Food waste within food supply chains: quantification and potential for change to 2050

http://ucce.ucdavis.edu/files/datastore/234-17.pdf

Preharvest and postharvest factors influencing vitamin C content of horticultural crops.

The antioxidant activity of pomegranate juices was evaluated by four different methods (ABTS, DPPH, DMPD, and FRAP) and compared to those of red wine and a green tea infusion. Commercial pomegranate juices showed an antioxidant activity (18-20 TEAC) three times higher than those of red wine and green tea (6-8 TEAC). The activity was higher in commercial juices extracted from whole pomegranates than in experimental juices obtained from the arils only (12-14 TEAC). HPLC-DAD and HPLC-MS analyses of the juices revealed that commercial juices contained the pomegranate tannin punicalagin (1500-1900 mg/L) while only traces of this compound were detected in the experimental juice obtained from arils in the laboratory. This shows that pomegranate industrial processing extracts some of the hydrolyzable tannins present in the fruit rind. This could account for the higher antioxidant activity of commercial juices compared to the experimental ones. In addition, anthocyanins, ellagic acid derivatives, and hydrolyzable tannins were detected and quantified in the pomegranate juices.

http://ucce.ucdavis.edu/files/datastore/234-60.pdf

Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing

Post Harvest Technology of Horticultural Crops

Modified atmospheres (MA), i.e., elevated concentrations of carbon dioxide and reduced levels of oxygen and ethylene, can be useful supplements to provide optimum temperature and relative humidity in maintaining the quality of fresh fruits and vegetables after harvest. MA benefits include reduced respiration, ethylene production, and sensitivity to ethylene; retarded softening and compositional changes; alleviation of certain physiological disorders; and reduced decay. Subjecting fresh produce to too low an oxygen concentration and/or to too high a carbon dioxide level can result in MA stress, which is manifested by accelerated deterioration. Packaging fresh produce in polymeric films can result in a commodity-generated MA. Atmosphere modification within such packages depends on film permeability, commodity respiration rate and gas diffusion characteristics, and initial free volume and atmospheric composition within the package. Temperature, relative humidity, and air movement around the package can influence the permeability of the film. Temperature also affects the metabolic activity of the commodity and consequently the rate of attaining the desired MA. All these factors must be considered in developing a mathematical model for selecting the most suitable film for each commodity.

Modified atmosphere packaging of fruits and vegetables.

Genotypic variation in composition and antioxidant activity was evaluated using 25 cultivars, 5 each of white-flesh nectarines, yellow-flesh nectarines, white-flesh peaches, yellow-flesh peaches, and plums, at the ripe (ready-to-eat) stage. The ranges of total ascorbic acid (vitamin C) (in mg/100 g of fresh weight) were 5−14 (white-flesh nectarines), 6−8 (yellow-flesh nectarines), 6−9 (white-flesh peaches), 4−13 (yellow-flesh peaches), and 3−10 (plums). Total carotenoids concentrations (in μg/100 g of fresh weight) were 7−14 (white-flesh nectarines), 80−186 (yellow-flesh nectarines), 7−20 (white-flesh peaches), 71−210 (yellow-flesh peaches), and 70−260 (plums). Total phenolics (in mg/100 g of fresh weight) were 14−102 (white-flesh nectarines), 18−54 (yellow-flesh nectarines), 28−111 (white-flesh peaches), 21−61 (yellow-flesh peaches), and 42−109 (plums). The contributions of phenolic compounds to antioxidant activity were much greater than those of vitamin C and carotenoids. There was a strong correlation...

http://ucce.ucdavis.edu/files/datastore/234-25.pdf

Adel A. Kader

Papers

Preharvest and postharvest factors influencing vitamin C content of horticultural crops.

Antioxidant activity of pomegranate juice and its relationship with phenolic composition and processing

Post Harvest Technology of Horticultural Crops

Modified atmosphere packaging of fruits and vegetables.

Antioxidant capacities, phenolic compounds, carotenoids, and vitamin C contents of nectarine, peach, and plum cultivars from California.