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Hossain M.B.,Dublin Institute of Technology | Hossain M.B.,Teagasc | Brunton N.P.,Teagasc | Patras A.,Biosystems Engineering | And 4 more authors.
Ultrasonics Sonochemistry | Year: 2012

The present study optimized the ultrasound assisted extraction (UAE) conditions to maximize the antioxidant activity [Ferric ion Reducing Antioxidant Power (FRAP)], total phenol content (TP) and content of individual polyphenols of extracts from marjoram. Optimal conditions with regard to amplitude of sonication (24.4-61.0 μm) and extraction temperature (15-35°C) and extraction time (5-15 min) were identified using response surface methodology (RSM). The results showed that the combined treatment conditions of 61 μm, 35°C and 15 min were optimal for maximizing TP, FRAP, rosmarinic acid, luteolin-7-O-glucoside, apigenin-7-O-glucoside, caffeic acid, carnosic acid and carnosol values of the extracts. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.45% to 1.55%. The extraction yields of the optimal UAE were significantly (p < 0.05) higher than solid/liquid extracts. Predicted models were highly significant (p < 0.05) for all the parameters studied with high regression coefficients (R 2) ranging from 0.58 to 0.989. © 2011 Elsevier B.V. All rights reserved.

Hossain M.B.,Dublin Institute of Technology | Hossain M.B.,Teagasc | Rai D.K.,Teagasc | Brunton N.P.,Teagasc | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2010

A total of 38 phenolic compounds in the solid/liquid extracts of five Lamiaceae spices, rosemary, oregano, sage, basil, and thyme, were identified in the present study using LC-ESI-MS/MS. These compounds were distributed in four major categories, namely, hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, flavonoids, and phenolic terpenes. Among them, the category of flavonoids was the largest, with 17 compounds. Identification of the phenolic compounds was carried out by comparing retention times and mass spectra with those of authentic standards. If standards were unavailable, phenolic compounds were identified on the basis of accurate mass of pseudomolecular [M - H] - ions and tandem mass spectrometry (MS/MS) data. The results of accurate mass measurements fit well with the elemental composition of the compounds. The diagnostic fragmentation patterns of the compounds during collision-induced dissociation (CID) elucidated the structural information of the compounds analyzed. © 2010 American Chemical Society.

Gonzalez-Fernandez C.,Agricultural Technological Institute of Castilla and Leon | Riano-Irazabal B.,Agricultural Technological Institute of Castilla and Leon | Molinuevo-Salces B.,Agricultural Technological Institute of Castilla and Leon | Blanco S.,University of Leon | Garcia-Gonzalez M.C.,Agricultural Technological Institute of Castilla and Leon
Applied Microbiology and Biotechnology | Year: 2011

There is great controversy regarding the best substrate (fresh or anaerobically digested swine slurry) for the development of microalgae-bacteria consortia. This study aims to elucidate the best substrate by assessing biomass productivity, microorganism predominance, and their ability for organic matter removal. In addition to the different substrates, different operational conditions and influent strengths were evaluated. Increasing organic matter content when favourable temperature and illumination conditions were present improved biomass production. However, these conditions were not favourable for microalgal growth, but they were favourable for bacteria. Regardless of the operational conditions, reactors fed with fresh slurry not only resulted in the highest biomass productivity, but also the greatest removal of total and soluble chemical oxygen demand (COD). On the other hand, reactors fed with digested slurry showed biomass productivity and COD removal values lower than those obtained for reactors fed with fresh slurry, most probably due to the recalcitrant nature of the former. Nevertheless, digested slurry was the substrate more appropriate for microalgae growth under harsh operational conditions (16 °C and 9-h illumination) at low influent strength and optimum operational conditions (30 °C and 24-h illumination) at higher influent strength. © 2011 Springer-Verlag.

Ahmed L.,Dublin Institute of Technology | Rico D.,University of Pamplona | Rico D.,Agricultural Technological Institute of Castilla and Leon | Martin-Diana A.B.,Agricultural Technological Institute of Castilla and Leon | Barry-Ryan C.,Dublin Institute of Technology
Journal of Agricultural and Food Chemistry | Year: 2011

Optimization of delactosed whey permeate (DWP) treatment for fresh-cut tomato was accomplished by evaluating different quality, nutritional and microbial markers. Response surface methodology was applied to obtain polynomial model equations. DWP concentration (0-5%) and storage (0-10 days) were used as independent factors in order to optimize the process. The analyses showed that increases in DWP concentration extended the quality of the fresh-cut tomato significantly (p < 0.05) by maintaining texture and antioxidant activity (FRAP) and controlling the spoilage during the storage. The total aerobic counts and yeast and molds were reduced by ∼1.5 log cfu/g and ∼1.0 log cfu/g respectively after 10 days of storage treated with 3% DWP. Ascorbic acid and lycopene were retained best within the range of 3 to 5% of DWP treatment. However, concentrations >3% were scored unacceptable by the sensory panel due to perceived off-odors. Predicted models were highly significant (p < 0.05) for all the markers studied in fresh-cut tomato with high regression coefficients (R2) ranging from 0.79 to 0.99. The study recommends the use of DWP at a concentration of 3% to extend the shelf life of fresh-cut tomato by preserving its quality and antioxidant properties during storage. © 2011 American Chemical Society.

Khiari Z.,Dublin Institute of Technology | Khiari Z.,University of Alberta | Rico D.,Agricultural Technological Institute of Castilla and Leon | Martin-Diana A.B.,Agricultural Technological Institute of Castilla and Leon | Barry-Ryan C.,Dublin Institute of Technology
Food Chemistry | Year: 2013

Gelatines were extracted from mackerel and blue whiting bones after chemical or enzymatic pre-treatments and their functional properties (solubility, foaming and emulsifying properties) were analysed. The pre-treatment significantly (p < 0.05) affected the composition and the functional properties of the extracted gelatines. The amino acid analyses showed that chemically pre-treated bone gelatines had higher imino acids (proline and hydroxyproline) contents compared to those extracted after the enzymatic pre-treatment, for both fish species. It was observed that all gelatines had higher solubility at low pH with a maximum value observed at pH 2. A significant effect of ionic strength was observed. Increasing the NaCl concentration to more than 1% resulted in a significant decrease of the solubility. Mackerel bone gelatines showed lower foaming capacity (FC) and higher foaming stability (FS) than blue whiting bone gelatines. Increasing the concentration of gelatine decreased the emulsifying activity index (EAI) but increased the stability index (ESI). The use of enzymes in the pre-treatment process gave gelatines with significantly (p < 0.05) higher EAI and ESI. © 2013 Elsevier Ltd. All rights reserved.

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