Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

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New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

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Phenolic compounds in Brassica vegetables.

Epidemiological studies associate whole grain consumption with a reduced risk of many diseases. This paper focuses on the antioxidant component of cereal dietary fibre starting from its chemical structure, bioavailability and biological meaning. By the critical assessment of the intervention studies performed using cereal bran and whole grains, the hypothesis that the slow and continuous release in the gut of the dietary fibre bound antioxidants determines the health benefits, is illustrated. In the last part of the work, new perspectives and technological possibilities to enhance the health potential of this cereal component are also highlighted.

Cereal dietary fibre: a natural functional ingredient to deliver phenolic compounds into the gut

BACKGROUND
The health benefits of organic foods are unclear.


PURPOSE
To review evidence comparing the health effects of organic and conventional foods.


DATA SOURCES
MEDLINE (January 1966 to May 2011), EMBASE, CAB Direct, Agricola, TOXNET, Cochrane Library (January 1966 to May 2009), and bibliographies of retrieved articles.


STUDY SELECTION
English-language reports of comparisons of organically and conventionally grown food or of populations consuming these foods.


DATA EXTRACTION
2 independent investigators extracted data on methods, health outcomes, and nutrient and contaminant levels.


DATA SYNTHESIS
17 studies in humans and 223 studies of nutrient and contaminant levels in foods met inclusion criteria. Only 3 of the human studies examined clinical outcomes, finding no significant differences between populations by food type for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection. Two studies reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not identify clinically meaningful differences. All estimates of differences in nutrient and contaminant levels in foods were highly heterogeneous except for the estimate for phosphorus; phosphorus levels were significantly higher than in conventional produce, although this difference is not clinically significant. The risk for contamination with detectable pesticide residues was lower among organic than conventional produce (risk difference, 30% [CI, -37% to -23%]), but differences in risk for exceeding maximum allowed limits were small. Escherichia coli contamination risk did not differ between organic and conventional produce. Bacterial contamination of retail chicken and pork was common but unrelated to farming method. However, the risk for isolating bacteria resistant to 3 or more antibiotics was higher in conventional than in organic chicken and pork (risk difference, 33% [CI, 21% to 45%]).


LIMITATION
Studies were heterogeneous and limited in number, and publication bias may be present.


CONCLUSION
The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.


PRIMARY FUNDING SOURCE
None.

Are organic foods safer or healthier than conventional alternatives? a systematic review

The objective of the present study was to evaluate the effect of three common cooking practices (i.e., boiling, steaming, and frying) on phytochemical contents (i.e., polyphenols, carotenoids, glucosinolates, and ascorbic acid), total antioxidant capacities (TAC), as measured by three different analytical assays [Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP), ferric reducing antioxidant power (FRAP)] and physicochemical parameters of three vegetables (carrots, courgettes, and broccoli). Water-cooking treatments better preserved the antioxidant compounds, particularly carotenoids, in all vegetables analyzed and ascorbic acid in carrots and courgettes. Steamed vegetables maintained a better texture quality than boiled ones, whereas boiled vegetables showed limited discoloration. Fried vegetables showed the lowest degree of softening, even though antioxidant compounds were less retained. An overall increase of TEAC, FRAP, and TRAP values was observed in all cooked vegetables, probably because of matrix softening and increased extractability of compounds, which could be partially converted into more antioxidant chemical species. Our findings defy the notion that processed vegetables offer lower nutritional quality and also suggest that for each vegetable a cooking method would be preferred to preserve the nutritional and physicochemical qualities.

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Effects of Different Cooking Methods on Nutritional and Physicochemical Characteristics of Selected Vegetables

Regular consumption of tomatoes has been associated with decreased risk of chronic degenerative diseases. Epidemiological findings confirm the observed health effects are due to the presence of different antioxidant molecules such as carotenoids, particularly lycopene, ascorbic acid, vitamin E and phenol compounds, particularly flavonoids. In this work, eight components contributing to the healthy quality of tomato (i. e. lycopene, beta-carotene, other carotenoids, flavonoids, phenolic acids, vitamins C and E, dry residue) were studied in the framework of breeding programs aiming to develop nutritional superior genotypes. Twelve tomato advanced breeding lines and six open pollinated cultivars were grown in strictly controlled conditions and analysed for their content of antioxidants. Among the 18 genotypes analysed, 10 showed a high level of total carotenoids, 6 high level of beta-carotene, 9 high lycopene levels, 15 high flavonoids and 2 relevant concentration of vitamin E. Based on such data and on a literature survey on tomato composition, an index, called index of antioxidant nutritional quality (I(QUAN)), was proposed as a tool to address the breeding programs in selecting tomato genotypes with antioxidant nutritional qualities.

Antioxidant nutritional quality of tomato.

Two pigmented wheat genotypes (blue and purple) and two black barley genotypes were fractionated in bran and flour fractions, examined, and compared for their free radical scavenging properties against 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (Trolox equivalent antioxidant capacity, TEAC), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), phenolic acid composition, carotenoid composition, and total anthocyanin content. The results showed that fractionation has a significant influence on the antioxidant properties, TPC, anthocyanin and carotenoid contents, and phenolic acid composition. Bran fractions had the greatest antioxidant activities (1.9-2.3 mmol TEAC/100 g) in all four grain genotypes and were 3-5-fold higher than the respective flour fractions (0.4-0.7 mmol TEAC/100 g). Ferulic acid was the predominant phenolic acid in wheat genotypes (bran fractions) while p-coumaric acid was the predominant phenolic acid in the bran fractions of barley genotypes. High-performance liquid chromatography analysis detected the presence of lutein and zeaxanthin in all fractions with different distribution patterns within the genotypes. The highest contents of anthocyanins were found in the middlings of black barley genotypes or in the shorts of blue and purple wheat. These data suggest the possibility to improve the antioxidant release from cereal-based food through selection of postharvest treatments.

Phytochemical profile of main antioxidants in different fractions of purple and blue wheat, and black barley

http://wpage.unina.it/fogliano/Slides%20FIPDes%20Seminars/Maggio%20DePascale%20EJA%202007.pdf

Sulphur fertilization may improve the nutritional value of Brassica rapa L. subsp. sylvestris

The effects of peeling and laboratory- or industrial-scale heating on carotenoid content and radical scavenging activity of tomato and tomato-virgin olive oil mixtures were investigated. A decrease in carotenoid content was detected only after long heating times. Such a decrease was lower for the unpeeled than for the peeled tomatoes. No change, either in lycopene concentration or in the chain-breaking activity of the lipophilic fractions, was observed when both laboratory- and industrial-scale heating treatments were performed on peeled-tomato puree containing 5% virgin olive oil. The aqueous fractions, including high-molecular-weight brown polymers formed as a consequence of heating, were also characterized for color, elementary composition and antioxidant activity.

Rita Pernice

Papers

Antioxidant nutritional quality of tomato.

Phytochemical profile of main antioxidants in different fractions of purple and blue wheat, and black barley

Sulphur fertilization may improve the nutritional value of Brassica rapa L. subsp. sylvestris

Effect of peeling and heating on carotenoid content and antioxidant activity of tomato and tomato-virgin olive oil systems

Glucosinolates profile of Brassica rapa L. subsp. Sylvestris L. Janch. var. esculenta Hort