Antioxidant activity in apples to drive processed applications?
maximise on the health-boosting antioxidant component of the fruit
with a new study backing up previous findings that suggest levels
of polyphenols are dependent on variety and post-harvest processing
Apples, and especially apple peels, have been found to have a potent antioxidant activity that can inhibit the growth of cancer cells, with the antioxidant activity of one apple equivalent to about 1500 mg of vitamin C.
A recent study by Italian scientists at the University of Naples supports previous findings that demonstrate average concentrations of major phenolic (antioxidant) compounds vary according to the type of apple.
Napolitano et al. used an HPLC method, and a flow injection MS/MS procedure to quantify cholorogenic acid and catechins, to determine epicatechin, phloridzin, phloretin xyloglucoside, caffeic acid and total phenols in four different apple varieties.
Antioxidant activities of the apples, from orchards in the Naples area, were measured by two different spectrophotometric methods. Measurements of the four varieties - Annurca Traditional, Red Delicious, Golden Delicious and Empire - were carried out at harvest and after three and four months of storage at 2o C.
The researchers conclude that the highest levels of polyphenols were recorded for Annurca and Empire varieties after three months cold storage, at 352.2 mg/kg and 388.4 mg/kg fresh weight, respectively.
"The genetic characteristics of the Annurca variety together with the anticipated harvest time and the peculiar postharvest conditions are likely responsible for this increase of the antioxidant activity," said the researchers.
Both recent animal and cell culture studies show that there is an association between the polyphenolic compounds found in apples and a wide variety of effects that may help prevent chronic disease. This supports the hypothesis that it is the phytochemicals found in fruits, especially apples, that impart healthy benefits.
More research is still needed to clarify the effects of these compounds in vivo. In order to examine the effects of these compounds in vivo, it is necessary to understand the bioavailability of the specific compounds, and the bioavailability of these compounds within the fruit matrix.
The European consumer crunches their way through about 20 kilos of apples a year, about 1.5 apples a day, compared to the US counterpart who eats about 9 kilos a year, one every four days.
In terms of production, China has emerged in the last few years as the single largest processor of apples in the world. Industry observers attribute the success of the Chinese sector to a huge apple crop that now exists there, which at some 20 million tonnes per annum dwarfs all other producers, and makes the Chinese apple sector around 5 times the size of the US industry and 10 ten times bigger than the largest EU based producers such as France and Italy.
Further development of the Chinese sector is slated to be boosted by international investment from key players such as Danone, Yakult, Heinz, Unilever and PepsiCo, and from the UK, Bulmers and Tesco in the retail sector, predicts market analysts Promar International.
The analysts forsee tha market niches in areassuch as organics and functional food and drink products will continue to develop for processed apples, with new formulations competing alongside the more traditional concentrate juice markets.
Full findings for the Italian apple study are published in the September 25 online edition of the Journal of Agriculture (10.1021/jf049822w S0021-8561(04)09822-X).