• Acrylamide formation in potato products

      Brunton, Nigel; Gormley, Ronan T.; Butler, Francis; Cummins, Enda; Danaher, Martin; O'Keeffe, Michael (Teagasc, 2006-08)
      Acrylamide, a substance classified as a potential carcinogen, occurs in heated starchy foods at concentrations many times in excess of levels permitted in drinking water. Early surveys indicated that levels of acrylamide in potato products such as French fries and potato crisps were the highest of the foodstuffs investigated. The present project addressed this issue by determining levels of acrylamide precursors (asparagine and reducing sugars) in raw potatoes and levels of acrylamide in (i) potato products from different storage regimes, (ii) spot-sampled potatoes purchased from a local supermarket, (iii) samples that received pre-treatments and were fried at different temperatures and (iv) French fries reheated in different ovens.A risk assessment of the estimated acrylamide intake from potato products for various cohorts of the Irish population was also conducted.
    • Comparison of phenolic and flavonoid content and antioxidant activity in vitro among potato varieties.

      Valcarel, Jesus; Reilly, Kim; Gaffney, Micheal T.; Brunton, Nigel; O'Brien, N. (Teagasc, 2011)
      Diets rich in fruits and vegetables have been associated with a lower incidence of cancer and heart disease, which may be related to the antioxidant activity of bioactive compounds present in these foods. Phenolic compounds are potent antioxidants in vitro, of which flavonoids are of particular interest for their potential positive impact on health. Potatoes are one of the most consumed vegetables in the world and therefore an important source of phenolics. In Ireland they are the third most important crop with a farm gate value of approximately 45 million euros annually. The aim of this work was to evaluate the antioxidant activity of methanolic solutions extracted from the skin and flesh of potato tubers against the stable radical DPPH and analyze its relationship to the content of total phenolics and total flavonoids.
    • Effect of organic and conventional cultivation techniques on yield, phenolic content, and sensory parameters in two carrot varieties

      Reilly, Kim; Gaffney, Micheal T.; Brunton, Nigel (Teagasc, 2011)
      Carrots are one of the most important field grown vegetables in Ireland with a farm gate value of 16 million euros in 2007. They contain health promoting bioactive compounds including carotenoids, phenolics and polyacetylenes. Organically grown vegetables are often perceived as healthier and to have better flavour. The objective of this study was to determine levels of phenolics and flavonoids in organic and conventionally grown carrots, and to determine if they can be distinguished by taste.
    • Effect of organic, conventional and mixed cultivation practices on soil microbial community structure and nematode abundance in a cultivated onion crop

      Reilly, Kim; Cullen, Eileen; Lola-Luz, Theodora; Stone, Dorothy; Valverde, Juan; Gaffney, Michael; Brunton, Nigel; Grant, Jim; Griffiths, Bryan S (Wiley, 2013-06-07)
      BACKGROUND: Responses of the soil microbial and nematode community to organic and conventional agricultural practices were studied using the Teagasc Kinsealy Systems Comparison trial as the experimental system. The trial is a long term field experiment which divides conventional and organic agriculture into component pest-control and soil treatment practices. We hypothesised that management practices would affect soil ecology and used community level physiological profiles (CLPP), microbial and nematode counts, and denaturing gradient gel electrophoresis (DGGE) to characterise soil microbial communities in plots used for onion (Allium cepa L.) cultivation. RESULTS: Microbial activity and culturable bacterial counts were significantly higher under fully organic management. Culturable fungi, actinomycete and nematode counts showed a consistent trend towards higher numbers under fully organic management but these data were not statistically significant. No differences were found in the fungal/bacterial ratio. DGGE banding patterns and sequencing of excised bands showed clear differences between treatments. Putative onion fungal pathogens were predominantly sequenced under conventional soil treatment practices whilst putative soil suppressive bacterial species were predominantly sequenced from the organic pest-control treatment plots. CONCLUSION: Organic management increased microbial activity and diversity. Sequence data was indicative of differences in functional groups and warrants further investigation.
    • A note on the effectiveness of selenium supplementation of Irish-grown Allium crops.

      Reilly, Kim; Valverde, Juan; Finn, Leo; Gaffney, Michael; Rai, Dilip K.; Brunton, Nigel (Teagasc (Agriculture and Food Development Authority), Ireland, 2014)
      Onions and other Allium crops contain high levels of dietary phenolics and, unlike many other crops, accumulate the beneficial mineral selenium. Selenium-enhanced Allium crops are of interest both from a public good perspective and as a market positioning strategy for growers. Field trials were carried out to i) identify onion and scallion varieties that contain high levels of health-promoting phenolic and flavonoid compounds as potential targets for selenium supplementation and ii) investigate selenium supplementation in the widely-grown commercial onion variety ‘Hyskin’ at different application rates of nitrogen fertilizer. Levels of selenium in onion bulbs were significantly increased from 0.5–5.9 μg/g dry weight (DW) to 40.6–70.0 μg/g DW.
    • Observations on the water distribution and extractable sugar content in carrot slices after pulsed electric field treatment

      Aguilo-Aguayo, Ingrid; Downey, Gerard; Keenan, Derek F.; Lyng, James G.; Brunton, Nigel; Rai, Dilip K (Elsevier, 2014-06-13)
      The impact of pulsed electric field (PEF) processing conditions on the distribution of water in carrot tissue and extractability of soluble sugars from carrot slices was studied. Time domain NMR relaxometry was used to investigate the water proton mobility in PEF-treated carrot samples. Three distinct transverse relaxation peaks were observed in untreated carrots. After PEF treatment only two slightly-overlapping peaks were found; these were attributed to water present in the cytoplasm and vacuole of carrot xylem and phloem tissues. This post-treatment observation indicated an increase in water permeability of tissues and/or a loss of integrity in the tonoplast. In general, the stronger the electric field applied, the lower the area representing transverse relaxation (T2) values irrespective of treatment duration. Moreover an increase in sucrose, β- and α-glucose and fructose concentrations of carrot slice extracts after PEF treatment suggested increases in both cell wall and vacuole permeability as a result of exposure to pulsed electric fields.
    • Potential of cultivar and crop management to affect phytochemical content in winter-grown sprouting broccoli (Brassica oleracea L. var. italica)

      Reilly, Kim; Valverde, Juan; Finn, Leo; Rai, Dilip K; Brunton, Nigel; Sorenson, Jens C; Sorenson, Hilmer; Gaffney, Michael (Wiley, 2013-07-08)
      BACKGROUND: Variety and crop management strategies affect the content of bioactive compounds (phenolics, flavonoids and glucosinolates) in green broccoli (calabrese) types, which are cultivated during summer and autumn in temperate European climates. Sprouting broccoli types are morphologically distinct and are grown over the winter season and harvested until early spring. Thus they show considerable potential for development as an import substitution crop for growers and consumers during the ‘hungry gap’ of early spring. The present study investigated the effect of variety and management practices on phytochemical content in a range of sprouting broccoli varieties. RESULTS: Yields were significantly higher in white sprouting broccoli varieties. Levels of phenolics and flavonoids were in the range 81.6-270.4 and 16.9–104.8 mg 100g -1 FW respectively depending on year and cultivar, and were highest in varieties TZ 5052, TZ 5055, Red Admiral and Improved White Sprouting. In-row spacing did not affect flavonoid content. Phenolic and flavonoid content generally increased with increasing floret maturity and levels were high in edible portions of the crop. Crop wastes (leaf and flower) contained 145.9-239.3 and 21.5–116.6 mg 100g -1 FW total phenolics and flavonoids respectively depending on cultivar, tissue and year. Climatic factors had a significant effect on phenolic and flavonoid content. Levels of total and some individual glucosinolates were higher in sprouting broccoli than in the green broccoli variety Ironman. CONCLUSION: Levels of total phenolics, flavonoids and glucosinolates are higher in sprouting than green broccoli types. Sprouting broccoli represents an excellent source of dietary bioactive compounds.
    • Status Report on Acrylamide in Potato Products

      Brunton, Nigel; Gormley, Ronan T.; Murray, Brendan (Teagasc, 2005-01-01)
      Acrylamide is a toxin that can potentially occur in high concentrations in heated starchy foods especially potato products such as crisps and french fries. In model systems isotopic substitution studies have demonstrated that acrylamide is formed via the Maillard type reaction between the amino acid aspargine and a carbonyl source such as the reducing sugars glucose and fructose. Levels of acrylamide in cooked potato products are primarily influenced by the levels of reducing sugars in the product and this in turn is influenced by storage time, temperature and variety of potato used. During cooking acrylamide formation begins to occur at temperatures above 100°C and increases up to temperatures of 220°C but decreases thereafter due to thermal degradation of the compound. Risk assessment studies on acrylamide intakes have been conducted in a number of countries and mg/kg body weight daily intakes have been estimated to be between 0.2-0.8. Adequate analytical techniques exist for quantification of acrylamide in potato and are mainly based around liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) techniques
    • Variation in bioactive content in broccoli (Brassica oleracea var. italica) grown under conventional and organic production systems

      Valverde, Juan; Reilly, Kim; Villacreces, Salvador; Gaffney, Michael; Grant, Jim; Brunton, Nigel (Wiley on behalf of Society of Chemical Industry, 2014-07-30)
      BACKGROUND Broccoli and other cruciferous vegetables contain a number of bioactive compounds, in particular glucosinolates and polyphenols, which are proposed to confer health benefits to the consumer. Demand for organic crops is at least partly based on a perception that organic crops may contain higher levels of bioactive compounds; however, insufficient research has been carried out to either support or refute such claims. RESULTS In this study we examined the effect of conventional, organic, and mixed cultivation practices on the content of total phenolics, total flavonoids, and total and individual glucosinolates in two varieties of broccoli grown over 2 years in a split-plot factorial systems comparison trial. Levels of total phenolics and total flavonoids showed a significant year-on-year variation but were not significantly different between organic and conventional production systems. In contrast, levels of the indolyl glucosinolates glucobrassicin and neoglucobrassicin were significantly higher (P < 0.05) under fully organic compared to fully conventional management. CONCLUSION Organic cultivation practices resulted in significantly higher levels of glucobrassicin and neoglucobrassicin in broccoli florets; however, other investigated compounds were unaffected by production practices.