Juan Valverde

Quality improvement and extension of shelf life by 1-methylcyclopropene in plum as affected by ripening stage at harvest

Abstract Plum ( Prunus domestica L. cv. ‘President’) fruits were harvested at two pre-climacteric stages of ripeness (stage 1 and stage 2), and then treated with 1-methylcyclopropene (1-MCP) at two doses (0.3 and 0.5 μl l −1 ) followed by 1, 2, 3, 4 and 5 weeks of cold storage and their respective 7 days of shelf life at 20 °C. Both 1-MCP doses were effective in terms of ethylene inhibition during shelf life after cold storage, for both ripening stages. Similarly, lower weight losses, delayed colour changes, reduced softening rate and diminished ripening index were found in 1-MCP treated plums than in controls at both stages of ripeness. Hence, during cold storage and shelf life, the efficacy of 1-MCP on ethylene production, weight loss, pulp firmness and ripening index was dose-dependent, while for colour and respiration rate the dose-dependence was only found during shelf life. The storability of 1-MCP treated plums could be extended up to 4 weeks of cold storage plus 7 days at 20 °C, and only up to 1 week of cold storage plus 7 days at 20 °C for controls. Then, 1-MCP is an effective tool for quality improvement and extension of shelf life in plums, and fruit might be harvested in stage 2 of ripening, at which the most desirable organoleptic attributes had been developed on tree.

Feasibility Study on the Use of Visible–Near-Infrared Spectroscopy for the Screening of Individual and Total Glucosinolate Contents in Broccoli

The potential of visible-near-infrared spectroscopy to determine selected individual and total glucosinolates in broccoli has been evaluated. Modified partial least-squares regression was used to develop quantitative models to predict glucosinolate contents. Both the whole spectrum and different spectral regions were separately evaluated to develop the quantitative models; in all cases the best results were obtained using the near-infrared zone between 2000 and 2498 nm. These models have been externally validated for the screening of glucoraphanin, glucobrassicin, 4-methoxyglucobrassicin, neoglucobrassicin, and total glucosinolates contents. In addition, discriminant partial least-squares was used to distinguish between two possible broccoli cultivars and showed a high degree of accuracy. In the case of the qualitative analysis, best results were obtained using the whole spectrum (i.e., 400-2498 nm) with a correct classification rate of 100% in external validation being obtained.

Effect of organic, conventional and mixed cultivation practices on soil microbial community structure and nematode abundance in a cultivated onion crop

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, 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.

Chitosan-Containing Bread Made Using Marine Shellfishery Byproducts: Functional, Bioactive, and Quality Assessment of the End Product

Chitosan is natures second most abundant polymer after cellulose and forms the structural support in crustacean shell material and Basidomycete mushroom stalks. Chitosan is a known antimicrobial agent but, to date, was not examined as an antimicrobial agent in bread formulations for the prevention of mold or rope formation. The aim of this work was to investigate the effects of chitosan generated from prawn shell byproducts on the color, moisture, and texture and crumb formation of bread. A secondary aim of this work was to determine the antimicrobial effect of chitosan added to bread at a rate of 1% against the rope spoilage pathogen Bacillus cereus along with natural molds. The addition of chitosan to bread with a molecular mass of 124000 ± 10000 g/mol and 19% deacetylated was found to inhibit B. cereus growth and rope formation in bread when monitored over 3-5 days. Natural mold growth was also significantly delayed in bread made using chitosan substitution of flour at 1% compared to the control bread, where mold was observed growing on the bread surface after 72 h when bread was incubated at 30 °C.

Variation in bioactive content in broccoli (Brassica oleracea var. italica) grown under conventional and organic production systems

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.

Polyacetylene levels in carrot juice, effect of pH and thermal processing

This research focuses on the study of polyacetylenes in carrot juice and their response to pH, storage and thermal processing conditions. Falcarindiol-3-acetate (FaDOAc) and falcarinol (FaOH) were in fresh carrot juice at concentrations of 73 and 233 μg/L, respectively. Reducing the pH of the raw carrot juice from its natural pH 6.13 to pH 3.5 resulted in 2 and 5 fold better extraction of FaDOAc and FaOH respectively in comparison to a control sample (pH 6.13). Polyacetylenes were retained better in acidified juices and cold storage temperatures (4 °C) for first week of storage with respect to untreated juices. An increase in FaDOAc and FaOH of 10- and 16-fold, respectively, as compared to raw unprocessed samples was observed when processing samples at 90 °C for 1 min. This was assumed to be due to cell wall polysaccharides dissolution. However, negative correlation between total polyacetylenes and hexoses was confirmed by (1)H NMR spectroscopy, indicating some biological links between polyacetylenes and soluble sugars.

Molecular Gastronomy in Ireland

This article summarizes the activities of molecular gastronomy (MG) in Ireland since the scientific discipline was first introduced in the country. MG has been developing over the last five years, however, the authors of this article have been trying to establish a strong MG infrastructure in Ireland. Indeed, a lot of work still needs to be done, but public interest and positive perceptions of “chemistry” have increased very quickly; consequently, there is great potential for further development. Indeed, we can now say that MG has crossed the Rubicon in Ireland.

Simultaneous Determination of Sulphoraphane and Sulphoraphane Nitrile in Brassica Vegetables using Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry

INTRODUCTION Several analytical methods exist for the determination of sulphoraphane or sulphoraphane nitrile from biological matrices and plant extracts. However, no UPLC-MS/MS method exists for the simultaneous detection of both. OBJECTIVE To develop and validate an UPLC-MS/MS method for the simultaneous analysis of sulphoraphane and sulphoraphane nitrile from Brassica oleracea L. ssp. italica METHODS This method was developed utilising an Acquity BEH C8 column with gradient elution combined with tandem mass spectrometry, using positive electrospray ionisation in multiple reaction monitoring mode. RESULTS The retention times for sulphoraphane and sulphoraphane nitrile were 0.4 and 0.6 min respectively, and total run time was 3 min. The method was validated for linearity, sensitivity, precision, accuracy, matrix effects and recovery. The method was employed to determine glucoraphanin hydrolysis products in broccoli and the predominant product was found to vary depending on the variety tested. It was also applied to the accurate determination of sulphoraphane and sulphoraphane nitrile in broccoli samples hydrolysed under different conditions. It was observed that the formation of sulphoraphane and sulphoraphane nitrile was influenced by the temperature of the reaction. CONCLUSION The validated UPLC-MS/MS method for simultaneous detection of sulphoraphane and sulphoraphane nitrile was shown to be applicable to broccoli plants and is expected to be applicable to other cruciferous sources.

Development of a Novel Functional Soup Rich in Bioactive Sulforaphane Using Broccoli (Brassica oleracea L. ssp. italica) Florets and Byproducts.

Broccoli florets are rich in health-promoting compounds such as glucoraphanin, the precursor of the bioactive compound sulforaphane. In addition, broccoli byproducts such as stalk also contain health-promoting compounds and represent attractive ingredients in the development of functional foods. The bioconversion of glucosinolates into bioactive isothiocyanates is affected by many factors including heat and therefore cooking of Brassica such as broccoli may result in significant loss of sulforaphane production. The aim of this study was to develop a suitable food system as a vehicle for the delivery of sulforaphane in the human diet in adequate quantities. To this end, the feasibility of dry-mix ready soup as a food matrix for the delivery of broccoli floret and byproducts was evaluated. In particular, this study investigated the bioconversion of glucosinolates into bioactive isothiocyanates during the cooking process of this novel food product by microwave heating. In addition to total isothiocyanate and sulforaphane content, other key physical and biochemical quality attributes of the broccoli floret- and byproduct-enriched soups were investigated. Total isothiocyanate and sulforaphane content in floret- and stalk-enriched soups was high in both cases and increased in the order stalk<floret. The overall acceptability of stalk containing soups was not significantly different compared with the control soups, whereas floret containing soups received significantly lower acceptability scores. These results suggest that ready soups prepared by microwave heating represent a feasible food product for the delivery of broccoli florets and byproducts which is compatible with the bioconversion of glucosinolates into bioactive isothiocyanates.

Cardioprotective potential of Irish macroalgae: generation of glycine betaine and dimethylsulfoniopropionate containing extracts by accelerated solvent extraction.

Accelerated solvent extraction (ASE®) was used to generate 18 macroalgal extracts from Irish seaweeds. The glycine betaine and dimethylsulfoniopriopionate content of the generated ASE® extracts were estimated using (1)H-NMR and confirmed for selected extracts using ultra performance liquid chromatography and mass spectrometry. Dimethylsulfoniopriopionate was only identified in the ASE® extract generated from Codium fragile ISCG0029. Glycine betaine was identified in the ASE® extract generated from Ulva intestinalis ISCG0356 using (1)H-NMR. Mass spectrometry analysis found that the seaweed species Cytoseira nodicaulis ISCG0070, Cytoseira tamariscofolia ISCG0283, and Polysiphonia lanosa ISCG0462 also had a glycine betaine content that ranged from 1.39 ng/ml to 105.11 ng/ml. Generated ASE® macroalgal extracts have potential for use as functional food ingredients in food products.