Newsgroup: it.salute.alimentazione
Titolo: Re: Gli antiossidanti di frutta e verdura

 Spinach -- 11260 Spinaci
Sono valori certi? Mi piacerebbe avere conferme di altre fonti... 

 A study from Tufts University in Boston ranks the antioxidant value of
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Uno studio della Tufts University di Boston classifica frutta e verdura in
base agli antiossidanti contenuti, grazie a un test chiamato ORAC che
appunto determina "the total antioxidant power of foods".
In pole position, come frutta con maggior concentrazione di antiossidanti
per 100 grammi, i mirtilli, le more, le fragole e i lamponi (a parte la
frutta secca che è ovviamente più concentrata, ma anche più zuccherina e
calorica). Tra le verdure, il cavolo e gli spinaci.
 
http://www.mdsupport.org/library/antiox.html
Antioxidant Values in Fruits And Vegetables
by Dan Roberts
A study from Tufts University in Boston ranks the antioxidant value of
commonly eaten fruits and vegetables using an analysis called ORAC (Oxygen
Radical Absorbance Capacity). This is a test tube analysis that measures
the total antioxidant power of foods and other chemical substances.
Antioxidants are special compounds that protect against oxidation, or
cellular damage caused by free radicals, and they have been shown to be
effective in helping to prevent retinal diseases such as macular
degeneration. Familiar antioxidants include vitamin E, vitamin C and beta
carotene. It may be important to remember that, while antioxidant vitamin
supplements are popular, it may be the combination of the nutrients in the
foods that have the greatest effect.
Top-scoring fruits and vegetables ORAC units per 100 grams (about 3½
ounces)
Fruits:
(ho aggiunto la traduzione in italiano)
Prunes -- 5570 Prugne secche
Raisins -- 2830 Uvetta
Blueberries -- 2400 Mirtilli
Blackberries -- 2036 More
Strawberries -- 1540 Fragole
Raspberries -- 1220 Lamponi
Plums -- 949 Prugne
Oranges -- 750 Arance
Red grapes -- 739 Uva rossa
Cherries -- 670 Ciliegie
Kiwi fruit -- 602 Kiwi
Grapefruit, pink -- 483 Pompelmo Rosa
Vegetables:
Kale -- 11770 Cavolo
Spinach -- 11260 Spinaci
Brussels sprout -- 1980 Cavoletti di Brussels
Alfalfa sprouts -- 1930 Germogli di Alfaalfa
Broccoli Flowers -- 1890 Cavolfiore
Beets -- 1840 Barbabietola
Red bell pepper -- 1710 Peperoni rossi
Onion -- 1450 Cipolla
Corn -- 1400 Mais
Eggplant -- 1390 Melanzana
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Beh, penso che i valori possono variare, ovviamente, a seconda della
varietà esatta di frutta o verdura che consideri, stato di conservazione,
ecc... Inoltre esistono diversi metodi per calcolare il potenziale
antiossidante, AFAIK.
Ho trovato anche quest'altra ricerca che riguarda in particolare alimenti
che si trovano in Italia. Anche se la metodologia non è la stessa usata
dalla Tufts (si usano appunto altri metodi per calcolare il potenziale
antiossidante, non l'ORAC), la "classifica" mi pare non dissimile: gli
spinaci sono in testa tra le verdure, more, lamponi e altre bacche tra la
frutta.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=12949370
 J Nutr. 2003 Sep;133(9):2812-9.Click here to read Links
    Total antioxidant capacity of plant foods, beverages and oils consumed
in Italy assessed by three different in vitro assays.
        * Pellegrini N,
        * Serafini M,
        * Colombi B,
        * Del Rio D,
        * Salvatore S,
        * Bianchi M,
        * Brighenti F.
    Department of Public Health, University of Parma, Parma, Italy.
    Epidemiologic studies have demonstrated an inverse association between
consumption of fruits and vegetables and morbidity and mortality from
degenerative diseases. The antioxidant content of fruits and vegetables may
contribute to the protection they offer from disease. Because plant foods
contain many different classes and types of antioxidants, knowledge of
their total antioxidant capacity (TAC), which is the cumulative capacity of
food components to scavenge free radicals, would be useful for
epidemiologic purposes. To accomplish this, a variety of foods commonly
consumed in Italy, including 34 vegetables, 30 fruits, 34 beverages and 6
vegetable oils, were analyzed using three different assays, i.e., Trolox
equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant
parameter (TRAP) and ferric reducing-antioxidant power (FRAP). These
assays, based on different chemical mechanisms, were selected to take into
account the wide variety and range of action of antioxidant compounds
present in actual foods. Among vegetables, spinach had the highest
antioxidant capacity in the TEAC and FRAP assays followed by peppers,
whereas asparagus had the greatest antioxidant capacity in the TRAP assay.
Among fruits, the highest antioxidant activities were found in berries
(i.e., blackberry, redcurrant and raspberry) regardless of the assay used.
Among beverages, coffee had the greatest TAC, regardless of the method of
preparation or analysis, followed by citrus juices, which exhibited the
highest value among soft beverages. Finally, of the oils, soybean oil had
the highest antioxidant capacity, followed by extra virgin olive oil,
whereas peanut oil was less effective. Such data, coupled with an
appropriate questionnaire to estimate antioxidant intake, will allow the
investigation of the relation between dietary antioxidants and oxidative
stress-induced diseases.
    PMID: 12949370 [PubMed - indexed for MEDLINE]
Qui c'è il testo integrale con le tabelle.
http://jn.nutrition.org/cgi/content/full/133/9/2812
Per quanto riguarda lo studio della Tufts,  non ho trovato il testo
integrale su Pubmed, ma potrebbe essere questo di cui riporto l'Abstract.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=10995120&query_hl=13&itool=pubmed_docsum
J AOAC Int. 2000 Jul-Aug;83(4):950-6. 	
    Analysis of botanicals and dietary supplements for antioxidant
capacity: a review.
    Prior RL, Cao G, Prior RL, Cao G.
    US Department of Agriculture, Agricultural Research Service, Jean Mayer
USDA Human Nutrition Research Center on Aging at Tufts University, Boston,
MA 02111, USA.
    Free radicals and other reactive species are considered to be important
causative factors in the development of diseases of aging such as cancer
and cardiovascular diseases. This relationship has led to considerable
interest in assessing the antioxidant capacity of foods and botanicals and
other nutritional antioxidant supplements. The use of the oxygen radical
absorbance capacity (ORAC) assay as a tool for antioxidant assessment is
described and proposed as a method for comparing botanical sources and for
standardizing nutritional supplements. The free radical or oxidant source
is important and direct comparisons cannot be made between procedures that
use different sources. The ORAC procedure uses
2,2'-azobis(2-amidinopropane) dihydrochloride as a peroxyl radical source,
which is relevant to biological systems because the peroxyl radical is the
most abundant free radical. Other oxidant sources (hydroxyl radical and
Cu++) can also be used to characterize antioxidants in botanicals.
Phenolics or polyphenolics are responsible for most of the antioxidant
capacity in fruits, vegetables, and most botanical antioxidant supplements.
Although little is known about the absorption and metabolism of these
components, improvement in the in vivo antioxidant status has been observed
in human subjects following consumption of antioxidant botanicals. The ORAC
method provides a basis from which to establish appropriate dietary intakes
that might impact health outcomes.
Sui diversi metodi per calcolare il potenziale antiossidante di un
alimento, infine...
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=12628499
Mutat Res. 2003 Feb-Mar;523-524:9-20
    Methodological considerations for characterizing potential antioxidant
actions of bioactive components in plant foods.
        * Aruoma OI.
    Department of Neuroinflammation, Faculty of Medicine, Division of
Neuroinflammation and Psychological Medicine, Imperial College London,
Charing Cross Hospital Campus, Fulham Palace Road, London W6 8RF, UK.
[...]
 Use continues to be made of several in vitro analytical tools to
characterise the antioxidant propensity of bioactive compounds in plant
foods and supplements. For example, the oxygen radical absorbance capacity
(ORAC), ferric reducing antioxidant power (FRAP), total oxidant scavenging
capacity (TOSC), the deoxyribose assay, assays involving oxidative DNA
damage, assays involving reactive nitrogen intermediates (e.g. ONOO(-)),
Trolox equivalent antioxidant capacity (TEAC) and the
2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. There is need to agree
governance on in vitro antioxidant methods based on an understanding of the
mechanisms involved. Because some of the assays are done in
non-physiological pH values, it is impossible to extrapolate the results to
physiological environment. The consensus of opinion is that a mix of these
tools should be used in assessing the antioxidant activities in vitro. The
proof of bio-efficacy must emanate from application of reliable in vivo
models where markers of baseline oxidative damage are examined from the
standpoint of how they are affected by changes in diet or by antioxidant
supplements. Copyright 2002 Elsevier Science B.V.
PMID: 12628499 [PubMed - indexed for MEDLINE]
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