A comparison of the nutritional value, sensory qualities, and food safety of organically and conventionally produced foods

Evaluation of the micronutrient composition of plant foods produced by organic and conventional agricultural methods

The aim of the present analysis was to evaluate the micronutrient content of plant foods produced by organic and conventional agricultural methods. Studies were identified from a search of electronic databases (1980-2007, inclusive) as well as manual searches. A total of 66 studies (describing 1440 micronutrient comparisons) were identified. Thirty-three studies (908 comparisons) satisfied the screening criteria which considered cultivar, harvesting, and soil conditions. In studies that satisfied the screening criteria, the absolute levels of micronutrients were higher in organic foods more often than in conventional foods (462 vs 364 comparisons, P=0.002), and the total micronutrient content, expressed as a percent difference, was higher in organic (+5.7%, P<0.001) as compared to conventionally grown produce. The micronutrient content of food groups was more frequently reported to be higher for organic vegetables and legumes compared to their conventional counterparts (vegetables, 267 vs 197, P<0.001; legumes, 79 vs 46, P=0.004). This trend was supported by a mean percent difference in micronutrient content favoring organic vegetables (+5.9%, P<0.001) and legumes (+5.7%, P<0.001). Further research is required to determine the effect of organic agricultural methods on a broader range of nutrients and their potential impact on health.

Application of an untargeted metabolomics approach for the identification of compounds that may be responsible for observed differential effects in chickens fed an organic and a conventional diet

The aim of this study was to apply an untargeted NMR and LC-MS-based metabolomics approach to detect potential differences between an organically and a conventionally produced feed, which caused statistically significant differences in growth, in the response to an immunological challenge and in the gene expression profiles in the small intestine of laying hens. A fractionation procedure was set up to create multiple fractions of the feed, which were subsequently analysed by NMR and UPLC-TOF/MS operating in positive mode. Comparison of the profiles revealed that the most apparent differences came from the isoflavones in the soy as well as a compound with a molecular mass of 441.202 (M + 1)⁺, which was identified as N,N'-diferuloylputrescine (DFP) and came from the corn. Whether the observed differences in effects are due to the higher levels of isoflavones and DFP is unclear, as is the fact whether the observed differences are typical for organic or conventional produced corn and soy. However, this study shows that this metabolomics approach is suitable for detecting potential differences between products, even in levels of compounds that would have been overlooked with a more targeted approach. As such, the method is suitable for a more systematic study on differences between conventionally and organically produced food.

Concentration of some heavy metals in organically grown primitive, old and modern wheat genotypes: implications for human health

The concentration of six HMs (Cd, Cr, Co, Pb, Hg and Ni) was analysed in 321 organically grown winter and spring wheat genotypes from six genotype groups, i.e. selections, old landraces, primitive wheat, spelt, old cultivars and cultivars. Also the potential risk of individual toxic HM to human health was estimated by using the Hazard Quotient (HQ). Significantly the lowest grain concentration of Cd was found in primitive wheat as compared to all other investigated genotype groups. Intake of HM by consumption of whole wheat grain was not found to pose a health risk to human for any of the investigated genotype groups. The bio-concentration factor of Cd for the different genotype groups indicated a lower ability to accumulate Cd for primitive wheat as compared to other genotype groups. The primitive wheat was found the most promising and might be of interest in future wheat breeding programs to develop wheat genotypes with low HMs concentration in the grain.

A metabolomic approach differentiates between conventional and organic ketchups

The agronomic environments in which tomatoes are cultivated potentially affect the levels of antioxidants and other metabolites in commercial products. In this study, biochemical and metabolomic techniques were used to assess the differences between ketchups produced by organic and conventional systems. An untargeted metabolomic approach using QToF-MS was used to identify those nutrients that have the greatest impact on the overall metabolomic profile of organic ketchups as compared to conventional ones. Individual polyphenols were quantified using LC-ESI-QqQ. This multifaceted approach revealed that the agronomic environment in which tomatoes are grown induces alterations in the content of antioxidant capacity, phenolics, and other metabolites in ketchups. Organic cultivation was found to provide tomatoes and tomato-derived products with a significantly higher content of antioxidant microconstituents, whereas glutamylphenylalanine and N-malonyltryptophan were detected only in conventional ketchups.

The influence of the fungal pathogen Mycocentrospora acerina on the proteome and polyacetylenes and 6-methoxymellein in organic and conventionally cultivated carrots (Daucus carota) during post harvest storage

Many carrots are discarded during post harvest cold storage due to development of fungal infections, caused by, e.g., Mycocentrospora acerina (liquorice rot). We compared the susceptibility of carrots grown under conventional and organic agricultural practices. In one year, organically cultivated carrots showed 3× to 7× more symptoms than conventionally cultivated, when studying naturally occurring disease at 4 and 6 months, respectively. On the other hand, we have developed a bioassay for infection studies of M. acerina on carrots and observed that organic roots were more susceptible after one month of storage than conventional ones, but no differences were apparent after four or six months storage. Levels of polyacetylenes (falcarinol, falcarindiol and falcarindiol-3-acetate) did not change, whereas the isocoumarin phytoalexin (6-methoxymellein) accumulated in infected tissue as well as in healthy tissue opposite the infection. The proteomes of carrot and M. acerina were characterized, the intensity of 33 plant protein spots was significantly changed in infected roots including up regulation of defence and stress response proteins but also a decrease of proteins involved in energy metabolism. This combined metabolic and proteomic study indicates that roots respond to fungal infection through altered metabolism: simultaneous induction of 6-methoxymellein and synthesis of defence related proteins.

Organically versus conventionally grown produce: common production inputs, nutritional quality, and nitrogen delivery between the two systems

One distinguishing conclusion found in most reviews of research studies comparing organically and conventionally grown produce is that variables shared alike by organic and conventional produce during production, harvest, and postharvest handling and storage were not applied. As a result, accurate and meaningful conclusions comparing the nutritional quality of organic and conventional produce are difficult to ascertain. Pairing common production variables such as the physical, biological, and chemical/nutritional attributes of soils, the irrigation sources and amounts, crop varieties, crop maturities and harvest dates, pre- and postharvest processing, handling, and/or storage methods, individually and collectively, provide greater clarity as to how inputs unique to organic and conventional systems affect produce quality. Variables to be paired during production, harvest, and postharvest handling and storage studies comparing organic and conventional produce are discussed along with findings indicating that organic crops often have higher dry matter, ascorbic acid, phenolic, and sugar and lower moisture, nitrate, and protein contents and yields than conventionally grown crops. Recent studies of nutritional quality in organic versus conventional produce also indicate that soil nitrogen delivery rates strongly affect nutritional quality. Nitrogen profiling is a promising new approach to improving the nutritional quality of both organic and conventional produce.

The Irish organic food market: shortfalls, opportunities and the need for research

In 2009 the Irish organic food market was forecasted to grow from €120 m to €239 m by 2013; however, recent figures set its value at just €90 m. An estimated 70% of this market is imported. Surveys of Irish consumers reveal that 66% of consumers prefer to buy local produce and most organic consumers are buying organic at supermarkets. This evidence reveals that Irish producers must trade at supermarkets, and promote 'local produce' to ensure their produce reach the majority of buyers. Seventy-eight % of organic rejecters state price and 21% state unawareness of the benefits as reasons for not buying organic. Many Irish consumers are buying organic food on the perceived belief that it is healthier, safer and tastes better; however, a review of studies on organic versus conventional foods in terms of health benefits, safety and sensory quality has shown that existing data is limited in scope and fails to show a clear trend. The review concludes with the need for a comprehensive study of a range of organic and conventional foods available to the Irish consumer in order to determine if differences in organic cultivation result in statistically significant differences in health linked compounds and sensory quality.

Verification of organic feed identity by fatty acid fingerprinting

The origin and authenticity of feed for laying hens is an important and fraud-susceptible aspect in the production of organic eggs. Chemical fingerprinting in combination with chemometric methods is increasingly used in conjunction with administrative controls to verify and safeguard the authenticity of food commodities. On the basis of fatty acid fingerprinting data of 36 organic and 60 conventional feeds, we have developed a chemometric classification model to discriminate between organic and conventional chicken feed. A two-factor partial least squares-discriminant analysis (PLS-DA) model was developed using 70% of the original data. External validation of the model with the remaining 30% of the data showed that all of the organic feeds and 90% of the conventional feeds (18 of 20) were correctly identified by the model. These results indicate that the PLS-DA model developed in this study could be routinely used to verify the identity of unknown or suspicious feed for laying hens.

Organic and conventional Coffea arabica L.: a comparative study of the chemical composition and physiological, biochemical and toxicological effects in Wistar rats

Differentiation between organic and conventional coffee has increased due to the growing demand and high consumption of healthy foods that contain compounds with antioxidant potential, which have been associated with the reduction of chronic diseases. We used organic and conventional coffee in powder 4% (w/w) and infusions 5%, 10% and 20% (w/v) incorporated in a commercial diet to test in vivo. The levels of chlorogenic acid, caffeine and trigonelline were determined by high performance liquid chromatography. The body weight, weight gain, food consumption, aberrant foci crypt, mucin depleted foci, stress biomarkers protein carbonyl and malondialdehyde, biochemical parameters and behavior of the rats were compared between the experimental and control groups within a framework of colon carcinogenesis. The organic coffee showed higher levels of chlorogenic acid, caffeine and trigonelline than conventional, however, this difference did not significantly affect behavior. The infusions had an antioxidant effect, reducing the levels of malondialdehyde; however, the biochemical parameters of the serum were not altered, and there was neither induction nor prevention of preneoplasic lesions.

Alimentos orgânicos na produção de refeições escolares: limites e possibilidades em uma escola pública em Florianópolis

OBJETIVO: O estudo objetivou analisar a introdução de alimentos orgânicos na produção de refeições em uma unidade escolar da Secretaria de Educação de Santa Catarina. MÉTODOS: O modelo de análise apresentou caráter exploratório, com base em um estudo de caso. Na coleta de dados, utilizaram-se a entrevista semiestruturada, a análise documental e a observação direta. RESULTADOS: Identificaram-se as possibilidades de aperfeiçoar a utilização de alimentos orgânicos, relacionadas com o planejamento de cardápios, com o sistema de compras, com o recebimento e o armazenamento dos alimentos. Constataram-se limites relacionados à inexistência de planejamento referente à compra e ao uso do alimento orgânico nos cardápios, ao fornecimento de alimentos orgânicos - tal como o despreparo de alguns fornecedores para atender as necessidades da escola -, e, principalmente, aos preços. CONCLUSÃO: Conclui-se que há necessidade de revisão na gestão adotada pela escola, incluindo-se estudo comparativo de preços, de estabelecimento de parcerias com fornecedores e da atuação dos agentes envolvidos com a alimentação escolar para o fortalecimento do programa. Destaca-se, ainda, a necessidade de novos estudos sobre a gestão de produção de refeições em escolas e sobre a utilização de alimentos orgânicos.

Phenolic acid concentrations in organically and conventionally cultivated spring and winter wheat

BACKGROUND

Organic crops are often thought to contain more phenolic secondary metabolites than conventional ones. This study evaluated the influence of organic and conventional farming on concentrations of phenolic acids in spring and winter wheat cultivars.

RESULTS

Five phenolic acids were identified: ferulic, sinapic, p-coumaric, vanillic and p-hydroxybenzoic acid. Ferulic acid was the main phenolic acid in the grain of all tested wheat varieties. Significant differences among the examined cultivars in concentration of particular compounds were observed. Concentrations of phenolic acids varied significantly in organic and conventional wheat. Levels of ferulic and p-coumaric acids, as well as the total phenolic acid content were higher in organic crops. Concentrations of sinapic acid in spring wheat, as well as vanillic and p-hydroxybenzoic acid levels in both types of wheat were significantly higher in conventional grains. The 1000 kernel weight (TKW) of spring and winter wheat was significantly lower in organic crops.

CONCLUSION

Organically produced spring and winter wheat had significantly higher concentrations of ferulic and p-coumaric acid as well as the total phenolic acid content than conventional wheat, though the differences in the levels of phenolics were not large. However, these differences are probably caused mainly by smaller size of organic wheat kernels (lower TKW).

Comparison of the content of bioactive substances and the inhibitory effects against rat plasma oxidation of conventional and organic hot peppers (Capsicum annuum L.)

The aim of this study was to evaluate the chemical compositions and antioxidative activities of hot pepper fruits cultivated with strict management by organic and conventional agricultural practices. The ascorbic acid content in the organically grown hot pepper (OGP) was significantly higher than that of conventionally grown hot pepper (CGP) in both green and red fruits. The content of other bioactive compounds such as flavonoids (apigenin, luteolin, quercetin) and total phenolics in OGP was typically higher than in CGP regardless of fruit color. In addition, the ABTS(+) radical-scavenging activity of OGP red fruits was significantly higher than that of CGP red fruits. Moreover, regardless of the color of the fruits, a higher antioxidative activity was observed in blood plasma from rats administered the OGP fruit extracts than in blood plasma from rats administered the CGP fruit extracts. It was hypothesized that the higher antioxidant activity of the OGP fruits may have resulted from the higher antioxidant content in the OGP fruits. These results suggest that consumption of pepper fruits may increase antioxidant activity in the blood, and OGP fruits may be more effective in increasing this antioxidant activity than CGP fruits.

Cultivar choice provides options for local production of organic and conventionally produced tomatoes with higher quality and antioxidant content

BACKGROUND

Tomatoes (Solanum lycopersicum L.) are widely consumed and well known for their health benefits, many of which have been associated with the high levels of antioxidants present in tomatoes. With a growing interest in local and organic foods, it would be helpful to determine whether farmers could naturally improve the quality and antioxidant content of tomatoes for sale in local markets. This study evaluated antioxidant properties, quality attributes, and yield for 10 tomato cultivars grown for 2 years using certified organic and conventional practices.

RESULTS

Cultivar and year effects impacted (P < 0.05) all tests conducted, while growing method influenced (P < 0.05) yield, soluble solids content, ascorbic acid, and antioxidant radical scavenging capacity. Even when accounting for year-to-year variability, cultivars in the highest groups had 1.35- to 1.67-fold higher antioxidant levels than cultivars in the lowest groups. 'New Girl', 'Jet Star', 'Fantastic', and 'First Lady' were always in the highest groups, while 'Roma' and 'Early Girl' consistently had the lowest antioxidant content.

CONCLUSION

Compared to production practices and environmental effects of years that are generally beyond the control of small-scale producers, choice of cultivar provides the simplest and most effective means of increasing antioxidant properties. Knowledge of tomato cultivars with naturally higher antioxidant levels could assist smaller-scale producers to grow fruit that may provide a competitive advantage and the opportunity to capitalize on the increasing popularity of locally grown, high-quality fresh produce.

Influence of industrial and alternative farming systems on contents of sugars, organic acids, total phenolic content, and the antioxidant activity of red beet (Beta vulgaris L. ssp. vulgaris Rote Kugel)

The contents of sugars, organic acids, total phenolic content, and the antioxidant activity were quantified in the flesh of red beet from conventional (CON), integrated (INT), organic (ORG), biodynamic (BD), and control farming systems using established methods. Significant differences were measured for malic acid, total phenolic content (TPC), and total antioxidant activity, where malic acid content ranged from 2.39 g kg(-1) FW (control) to 1.63 g kg(-1) FW (CON, ORG, and INT). The highest TPC was measured in BD and control samples (0.677 and 0.672 mg GAE g(-1), respectively), and the lowest in CON samples (0.511 mg GAE g(-1)). Antioxidant activity was positively correlated with TPC (r2=0.6187) and ranged from 0.823 μM TE g(-1) FW to 1.270 μM TE g(-1) FW in CON and BD samples, respectively, whereas total sugar content ranged from 21.03 g kg(-1) FW (CON) to 31.58 g kg(-1) FW (BD). The importance of sugars, organic acids, phenols, and antioxidants for human health, as well as for plant resilience and health, gained from this explorative study, is discussed and put into perspective.

Mineral composition of organically grown wheat genotypes: contribution to daily minerals intake

In this study, 321 winter and spring wheat genotypes were analysed for twelve nutritionally important minerals (B, Cu, Fe, Se, Mg, Zn, Ca, Mn, Mo, P, S and K). Some of the genotypes used were from multiple locations and years, resulting in a total number of 493 samples. Investigated genotypes were divided into six genotype groups i.e., selections, old landraces, primitive wheat, spelt, old cultivars and cultivars. For some of the investigated minerals higher concentrations were observed in selections, primitive wheat, and old cultivars as compared to more modern wheat material, e.g., cultivars and spelt wheat. Location was found to have a significant effect on mineral concentration for all genotype groups, although for primitive wheat, genotype had a higher impact than location. Spring wheat was observed to have significantly higher values for B, Cu, Fe, Zn, Ca, S and K as compared to winter wheat. Higher levels of several minerals were observed in the present study, as compared to previous studies carried out in inorganic systems, indicating that organic conditions with suitable genotypes may enhance mineral concentration in wheat grain. This study also showed that a very high mineral concentration, close to daily requirements, can be produced by growing specific primitive wheat genotypes in an organic farming system. Thus, by selecting genotypes for further breeding, nutritional value of the wheat flour for human consumption can be improved.

Fruit and soil quality of organic and conventional strawberry agroecosystems

Background

Sale of organic foods is one of the fastest growing market segments within the global food industry. People often buy organic food because they believe organic farms produce more nutritious and better tasting food from healthier soils. Here we tested if there are significant differences in fruit and soil quality from 13 pairs of commercial organic and conventional strawberry agroecosystems in California.

Methodology/Principal Findings

At multiple sampling times for two years, we evaluated three varieties of strawberries for mineral elements, shelf life, phytochemical composition, and organoleptic properties. We also analyzed traditional soil properties and soil DNA using microarray technology. We found that the organic farms had strawberries with longer shelf life, greater dry matter, and higher antioxidant activity and concentrations of ascorbic acid and phenolic compounds, but lower concentrations of phosphorus and potassium. In one variety, sensory panels judged organic strawberries to be sweeter and have better flavor, overall acceptance, and appearance than their conventional counterparts. We also found the organically farmed soils to have more total carbon and nitrogen, greater microbial biomass and activity, and higher concentrations of micronutrients. Organically farmed soils also exhibited greater numbers of endemic genes and greater functional gene abundance and diversity for several biogeochemical processes, such as nitrogen fixation and pesticide degradation.

Conclusions/Significance

Our findings show that the organic strawberry farms produced higher quality fruit and that their higher quality soils may have greater microbial functional capability and resilience to stress. These findings justify additional investigations aimed at detecting and quantifying such effects and their interactions.

Birds select conventional over organic wheat when given free choice

BACKGROUND

Global demand for organic produce is increasing by euro4 billion annually. One key reason why consumers buy organic food is because they consider it to be better for human and animal health. Reviews comparing organic and conventional food have stated that organic food is preferred by birds and mammals in choice tests.

RESULTS

This study shows the opposite result-that captive birds in the laboratory and wild garden birds both consumed more conventional than organic wheat when given free choice. There was a lag in preference formation during which time birds learnt to distinguish between the two food types, which is likely to explain why the present results differ from those of previous studies. A further experiment confirmed that, of 16 potential causal factors, detection by birds of consistently higher levels of protein in conventional seeds (a common difference between many organic and conventional foodstuffs) is the likely mechanism behind this pattern.

CONCLUSION

The results of this study suggest that the current dogma that organic food is preferred to conventional food may not always be true, which is of considerable importance for consumer perceptions of organically grown food.

Consuming organic versus conventional vegetables: the effect on nutrient and contaminant intakes

The health benefits of consuming organic compared to conventional foods are unclear. This study aimed at evaluating the nutrient and contaminant intake of adults through consumption of organic versus conventional vegetables, namely carrots, tomatoes, lettuce, spinach and potatoes. A probabilistic simulation approach was used for the intake assessment in two adult populations: (1) a representative sample of Belgians (n=3245) and (2) a sample of Flemish organic and conventional consumers (n=522). Although significant differences in nutrient and contaminant contents were previously found between organic and conventional vegetables, they were inconsistent for a component and/or vegetable. These findings were translated here into inconsistent intake assessments. This means that the intake of specific nutrients and contaminants can be higher or lower for organic versus conventional vegetables. However, when considering the consumption pattern of organic consumers, an increase in intake of a selected set of nutrients and contaminants is observed, which are explained by the general higher vegetable consumption of this consumer group. In public health terms, there is insufficient evidence to recommend organic over conventional vegetables. The general higher vegetable consumption of organic compared to conventional consumers outweighs usually the role of differences in nutrient and contaminant concentrations between organic and conventional vegetables.

Effects of organic and conventional cultivation methods on composition of eggplant fruits

Organic food is associated by the general public with improved nutritional properties, and this has led to increasing demand for organic vegetables. The effects of organic and conventional cultivation methods on dry matter, protein, minerals, and total phenolic content has been studied for two successive years in two landraces and one commercial hybrid of eggplant. In the first year, organically produced eggplants had higher mean contents (expressed on a fresh weight basis) of K (196 vs 171 mg 100 g(-1)), Ca (11.1 vs 8.7 mg 100 g(-1)), Mg (6.0 vs 4.6 mg 100 g(-1)), and total phenolics (49.8 vs 38.2 mg 100 g(-1)) than conventionally grown eggplants. In the second year, in which matched plots having a history of organic management were cultivated following organic or conventional fertilization practices, organically produced eggplants still had higher contents of K (272 vs 249 mg 100 g(-1)) and Mg (8.8 vs 7.6), as well as of Cu (0.079 vs 0.065 mg 100 g(-1)), than conventionally fertilized eggplants. Conventionally cultivated eggplants had a higher polyphenol oxidase activity than organically cultivated ones (3.19 vs 2.17 enzyme activity units), although no differences in browning were observed. Important differences in mineral concentrations between years were detected, which resulted in many correlations among mineral contents being significant. The first component of the principal component analysis separates the eggplants according to year, whereas the second component separates them according to the cultivation method (organic or conventional). Overall, the results show that organic management and fertilization have a positive effect on the accumulation of certain beneficial minerals and phenolic compounds in eggplant and that organically and conventionally produced eggplants might be distinguished according to their composition profiles.

Effect of organic production and fertilizer variables on the sensory properties of pac choi (Brassica rapa var. Mei Qing Choi) and tomato (Solanum lycopersicum var. Bush Celebrity)

BACKGROUND

The increased popularity of organic production has amplified the need for research that will help in understanding how this production system affects the final quality of vegetables. The effects of organic and conventional production on the sensory characteristics of pac choi (often called bok choy) and tomato were studied. Samples were grown in high tunnel and field environments at the Kansas State University Horticulture Research Center located in Olathe, Kansas. Highly trained descriptive panelists from the Sensory Analysis Center at Kansas State University used previously developed flavor lexicons for tomatoes and leafy greens to evaluate the samples.

RESULTS

ANOVA at a 95% confidence level was used to detect significant differences between treatments for individual attributes. Crispness, green-grassy/leafy, piney, and pungent attributes were normally higher in conventional pac choi only for the field samples. Pac choi grown in high tunnels showed slight differences only at individual amounts of fertilizer. Organic tomatoes grown in the field were generally juicier and less mealy compared to conventionally grown tomatoes. In the high tunnel, organic tomatoes were generally stronger in the characteristic tomato aroma. However, all differences generally were very small.

CONCLUSION

It can be concluded that organic and conventional production systems do not create major sensory differences in the vegetables evaluated. The few differences that do exist are so small they may not be of practical importance.

Effect of thermal treatments on phytochemicals in conventionally and organically grown berries

BACKGROUND

Consumer demand for organic foods is increasing despite a lack of conclusive evidence of nutritional superiority of organically grown produce. The objective of this investigation was to evaluate the effects of thermal treatments on phytochemicals in conventionally and organically grown berries. Two cultivars of conventionally and organically grown red raspberries and blueberries were analysed for total anthocyanins, total and specific phenolic compounds and total antioxidant activity. Fresh berries were thermally processed into cans and juice/puree with and without blanching, and the changes in phytochemicals were monitored.

RESULTS

Total anthocyanin and phenolic contents of berries were not influenced by the agricultural production system. Total antioxidant activity of berries was also not influenced by the production system, but antioxidant activity varied significantly between cultivars. After canning, total anthocyanins decreased by up to 44%, while phenolic contents and antioxidant activity of both berries generally increased by up to 50 and 53% respectively. The level of changes in phytochemicals during berry puree/juice processing was influenced by blanching and type of berries.

CONCLUSION

Phenolic contents and antioxidant activities of berries increased while total anthocyanins decreased during canning. Blanching prior to puree/juice processing improved the retention of phytochemicals in blueberries.

Influence of the input system (conventional versus organic farming) on metabolite profiles of maize ( Zea mays ) kernels

Maize ( Zea mays ) kernels grown conventionally and organically, respectively, were investigated using a gas chromatography/mass spectrometry (GC/MS)-based metabolite profiling methodology. By analysis of three cultivars grown at two locations with different input systems and at a third location where both organic and conventional farming were applied, the impact of the growing regime on the metabolite spectrum should be put into the context of natural variability. The applied analytical approach involved consecutive extraction of freeze-dried maize flour and subsequent subfractionation. Approximately 300 compounds from a broad spectrum of chemical classes were detected, of which 167 were identified. The metabolite profiling data were statistically assessed via principal component analysis (PCA) and analysis of variance (ANOVA). The PCA demonstrated that the observed separations were mainly due to genetic differences (cultivars) and environmental influences. The different input systems (conventional/organic) only led to minor differentiations. ANOVA and quantification of selected constituents confirmed these observations. Only three metabolites (malic acid, myo-inositol, and phosphate) were consistently different because of the employed input system if samples from all field trials were considered.

Effect of organically and conventionally produced diets on jejunal gene expression in chickens

Using a nutrigenomics approach we studied the response of second-generation chickens at a transcriptional level to organically grown feed ingredients compared with conventionally grown feed ingredients. Both diets consisted of the same amounts of ingredients, the only difference was the production method. Gene expression was analysed in jejuni using whole genome chicken cDNA arrays. After analysis, forty-nine genes were found to be differentially regulated between chickens fed on the different diets, independent of their genetic background. Of these forty-nine genes, seven genes were involved in cholesterol biosynthesis. Genes involved in cholesterol biosynthesis were higher expressed in jejuni from organically fed birds. Other genes found to be regulated were involved in immunological processes, such as B-G protein (part of chicken major histocompatibility complex), chemokine ah221, and the immunoglobulin heavy chain. Using quantitative PCR the effect of genetic background on the differential expression of genes was studied. Differences in gene expression existed between animals fed different diets as well as between different chicken lines. This indicated that diet and genetic background influence the transcriptional response of the jejunum. This is the first time that significant differences in gene expression were shown between animals on diets with organically or conventionally produced ingredients.

Nutritional quality of organic foods: a systematic review

BACKGROUND

Despite growing consumer demand for organically produced foods, information based on a systematic review of their nutritional quality is lacking.

OBJECTIVE

We sought to quantitatively assess the differences in reported nutrient content between organically and conventionally produced foodstuffs.

DESIGN

We systematically searched PubMed, Web of Science, and CAB Abstracts for a period of 50 y from 1 January 1958 to 29 February 2008, contacted subject experts, and hand-searched bibliographies. We included peer-reviewed articles with English abstracts in the analysis if they reported nutrient content comparisons between organic and conventional foodstuffs. Two reviewers extracted study characteristics, quality, and data. The analyses were restricted to the most commonly reported nutrients.

RESULTS

From a total of 52,471 articles, we identified 162 studies (137 crops and 25 livestock products); 55 were of satisfactory quality. In an analysis that included only satisfactory-quality studies, conventionally produced crops had a significantly higher content of nitrogen, and organically produced crops had a significantly higher content of phosphorus and higher titratable acidity. No evidence of a difference was detected for the remaining 8 of 11 crop nutrient categories analyzed. Analysis of the more limited database on livestock products found no evidence of a difference in nutrient content between organically and conventionally produced livestock products.

CONCLUSIONS

On the basis of a systematic review of studies of satisfactory quality, there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs. The small differences in nutrient content detected are biologically plausible and mostly relate to differences in production methods.

Three-year comparison of the polyphenol contents and antioxidant capacities in organically and conventionally produced apples ( Malus domestica Bork. Cultivar 'Golden Delicious')

The present study was performed to evaluate the polyphenol content and antioxidant capacity of apples (cv. ;Golden Delicious') grown under defined organic and conventional conditions. Apples were harvested at five comparable commercial farms over the course of three years (2004-2006). In 2005 and 2006 the antioxidant capacity was 15% higher (p < 0.05) in organically produced apples than in conventionally produced fruits. In 2005 significantly higher polyphenol concentrations were found in the organically grown apples. In 2004 and 2006 no significant differences were observed (2004, 304 +/- 68 microg/g organic vs 284 +/- 69 microg/g conventional, p = 0.18; 2005, 302 +/- 58 micro/g organic vs 253 +/- 41 microg/g conventional, p = 0.002; 2006, 402 +/- 100 microg/g organic vs 365 +/- 58 microg/g conventional, p = 0.17). Year-to-year variations in the antioxidant capacity and the polyphenol content of up to 20% were more significant than the production method found within one year. Finally, flavanols and flavonols were major determinants of the antioxidant capacities in these apples. Overall, the production method had a smaller impact on the variation in the polyphenol content and antioxidant capacity of apples than the yearly climate.