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Articles 421 - 450 of 551

Full-Text Articles in Food Science

Barley For Brewing: Characteristic Changes During Malting, Brewing And Applications Of Its By-Products, Mahesh Gupta, Nissreen Abu-Ghannam, Eimear Gallaghar Aug 2010

Barley For Brewing: Characteristic Changes During Malting, Brewing And Applications Of Its By-Products, Mahesh Gupta, Nissreen Abu-Ghannam, Eimear Gallaghar

Articles

Barley is the basic raw material for brewing. Its chemical composition, brewing, and technological indices are highly determinative for the beer quality and the economical efficiency of the brewing process. Barley is rich in protein, carbohydrates, dietary fibers, minerals, and vitamins. The presence of non starch polysaccharides as mixed linkage (1-3),(1-4)-β-D-glucans and arabinoxylans together with the enzymes are responsible for barley modification. Malting is a complex process that involves many enzymes; important ones are α-amylase, β-amylase, α-glucosidase, and limit dextrinase. During the process of malting and brewing, the by-products left after separation of the wort are rich in protein, fibers, …


Effect Of Hydrothermal Processing On Colour, Antioxidant And Free Radical Scavenging Capacities Of Edible Irish Brown Seaweeds, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam, Shilpi Gupta Jul 2010

Effect Of Hydrothermal Processing On Colour, Antioxidant And Free Radical Scavenging Capacities Of Edible Irish Brown Seaweeds, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam, Shilpi Gupta

Articles

The effect of heat processing on change in colour (ΔE), level of bioactive compounds and overall antioxidant capacity in raw and heat processed Irish brown seaweeds was investigated. Raw seaweeds were heated at 85, 95, 100, 110 and 121 °C for 15 min in an autoclave and the samples were extracted with 60% methanol. Total phenol (TPC), total tannin (TTC), DPPH• scavenging and metal chelating ability (FIC) were significantly higher (p < 0.05) at 85 °C while the value of ΔE, total flavonoid (TFC), total sugar (TSC), lipid peroxidation and H2O2 scavenging capacity were higher at 95 °C, as compared to raw seaweeds, in all the species studied. Results showed that heat treatment affects not only the content of bioactive compounds in seaweeds but also beneficial biological activity associated with these compounds which can suggest new processing for the application of seaweeds extract as nutraceutical.


Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone Jun 2010

Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone

Articles

A confirmatory method has been developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in annex IV of council regulation 2377/90 and therefore prohibited for the use in animal husbandry. Milk samples are extracted by acetonitrile with addition of NaCl, while honey samples are first dissolved in water before a similar extraction. Honey extracts undergo a hexane wash to remove impurities. Both milk and honey extracts are evaporated to dryness and reconstituted in initial mobile phase. These are then injected onto an LC-MS/MS system and …


A Study Of The Physicochemical And Sensory Properties Of Organic And Conventional Potatoes (Solanum Tuberosum) Before And After Baking, Catherine Barry-Ryan, Roisin Burke, Clare Gilsenan Apr 2010

A Study Of The Physicochemical And Sensory Properties Of Organic And Conventional Potatoes (Solanum Tuberosum) Before And After Baking, Catherine Barry-Ryan, Roisin Burke, Clare Gilsenan

Articles

The objective of this study was to investigate if there were any differences in the physicochemical and sensory properties of organic and conventional potatoes (cv. Orla). The conventional potatoes had a lower dry matter content (P < 0.05) and a slightly softer texture (P V 0.05) than the organic potatoes. The trained panel perceived the conventional baked potato to be slightly softer, less adhesive and wetter than the organic baked potato (P


An Assessment Of The Antioxidant And Antimicrobial Activity Of Six Species Of Edible Irish Seaweeds, Sabrina Cox, Nissreen Abu-Ghannam, Shilpi Gupta Apr 2010

An Assessment Of The Antioxidant And Antimicrobial Activity Of Six Species Of Edible Irish Seaweeds, Sabrina Cox, Nissreen Abu-Ghannam, Shilpi Gupta

Articles

Six species of edible Irish seaweeds; Laminaria digitata, Laminaria saccharina, Himanthalia elongata, Palmaria palmata, Chondrus crispus and Enteromorpha spirulina were screened for potential bioactivity. Extraction of secondary metabolites was carried out using different solvents to determine antioxidant and antimicrobial properties of the dried extracts. The total phenolic contents of dried methanolic extracts were significantly different (p < 0.05). H. elongata exhibited highest phenolic content at 151.3 mg GAE/g of seaweed extract and also had the highest DPPH scavenging activity (p < 0.05) with a 50% inhibition (EC50) level at 0.125μg/ml of extract. H. elongata also had the highest total tannin and total flavonoid contents (p < 0.05) of 38.34 mg CE/g and 42.5 mg QE/g, respectively. Antimicrobial activity was determined using a microtitre method which allowed detection of bacterial growth inhibition at low levels. All methanolic seaweed extracts inhibited the food spoilage and food pathogenic bacteria tested; Listeria monocytogenes, Salmonella abony, Enterococcus faecalis and Pseudomonas aeruginosa, except C. crispus extracts. It was found that dried methanolic extracts of red and green seaweeds had significantly lower antimicrobial activity than the brown species; H. elongata had the highest antimicrobial activity with up to 100% inhibition. In the studied work, the antimicrobial activity of red and green seaweed extracts significantly increased when ethanol and acetone were used as extraction solvents (p < 0.05). Inhibition of E. faecalis with C. crispus extracts increased from 39.28 to 100% when ethanol and acetone were applied as solvents.


Antioxidant Capacity And Polyphenol Content Of Brown Seaweeds After Heat Processing, Gaurav Rajauria, Shilpi Gupta, Nissreen Abu-Ghannam, Amit Jaiswal Mar 2010

Antioxidant Capacity And Polyphenol Content Of Brown Seaweeds After Heat Processing, Gaurav Rajauria, Shilpi Gupta, Nissreen Abu-Ghannam, Amit Jaiswal

Articles

Seaweeds or marine macroalgae are renewable living resources which are also used as food, feed and fertilizer in many parts of the world. They are able to produce a great variety of secondary metabolites characterized by a broad spectrum of biological behavior such as antibacterial and antioxidant activities. The effect of heat treatment was investigated on the level of bioactive compounds and changes in the overall antioxidant capacity of edible Irish brown seaweeds namely Himanthalia elongata, Laminaria saccharina and Laminaria digitata. In order to make the seaweeds safe and edible, they were heated at 85, 95, 100, 110 and 121°C …


The Problem Of Antimicrobial Resistance In The Foodchain, Ciara Walsh Jan 2010

The Problem Of Antimicrobial Resistance In The Foodchain, Ciara Walsh

Reports

Antimicrobial resistance (AMR) associated with the food chain is currently a subject of major interest to many food chain stakeholders. In response safefood commissioned this report to update our knowledge of this area and to raise awareness of the issue. Its primary focus is on the food chain where it impacts consumer health. This review will inform and underpin any future action to be taken by safefood with regard to AMR.


Effect Of Ultrasonic Processing On Food Enzymes Of Industrial Importance, Paula Bourke, Brijesh Tiwari, Colm O Donnell, Patrick J. Cullen Jan 2010

Effect Of Ultrasonic Processing On Food Enzymes Of Industrial Importance, Paula Bourke, Brijesh Tiwari, Colm O Donnell, Patrick J. Cullen

Articles

In the last decade power ultrasound has emerged as an alternative processing option to conventional thermal approaches for pasteurisation and sterilisation of food products. While sonication alone is not adequate for inactivation of various spoilage and harmful enzymes present in food, ultrasound in combination with mild heat treatment and/or pressure has shown potential for both enzyme and pathogen inactivation. Numerous studies have investigated ultrasound for inactivating enzymes such as pectinmethylesterase, polyphenoloxidases and peroxidases responsible for deterioration of fruit & vegetable juice and various enzymes pertinent to milk quality. The efficacy of ultrasound for the inactivation of enzymes in food is …


Quality And Safety Assessment During The Ozonation Of Cloudy Apple Juice, Sonal Patil, B. Torres, Brijesh Tiwari, Hilda Wingaard, Paula Bourke, Patrick J. Cullen, C. O'Donnell, Vasilis Valdramidis Jan 2010

Quality And Safety Assessment During The Ozonation Of Cloudy Apple Juice, Sonal Patil, B. Torres, Brijesh Tiwari, Hilda Wingaard, Paula Bourke, Patrick J. Cullen, C. O'Donnell, Vasilis Valdramidis

Articles

Traditionally, ozone processing within the food industry has focused on solid foods by either gaseous treatment or washing with ozonated water. However, with the FDA’s approval of ozone as a direct additive to food, the potential for liquid applications has emerged. This study investigates the effect of ozone processing on microbial inactivation (E. coli ATCC 25922 and NCTC 12900), and quality parameters (colour, phenolic content) of apple juice. Apple juice samples were ozonated at room temperature (20±1.5oC) with an ozone concentration of 0.048 mg O3 min-1 ml-1 and treatment time of 0 to 10 …


Untreated And Enzyme-Modified Bovine Whey Products Reduce Association Of Salmonella Typhimurium, Escherichia Coli O157:H7 And Cronobacter Malonaticus (Formerly Enterobacter Sakazakii) To Caco-2 Cells, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan Jan 2010

Untreated And Enzyme-Modified Bovine Whey Products Reduce Association Of Salmonella Typhimurium, Escherichia Coli O157:H7 And Cronobacter Malonaticus (Formerly Enterobacter Sakazakii) To Caco-2 Cells, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan

Articles

Adhesion of a micro-organism to a cell surface is often considered to be the first step in pathogenesis. Inhibiting this process may have therapeutic effects in vivo. This study investigates the inhibitory effects of various bovine whey products on the association of Salm. Typhimurium, E. coli O157:H7 and C. malonaticus (formerly Enterobacter sakazakii) to the human CaCo-2 cell line. Invasion of CaCo-2 cells by Salm. Typhimurium and C. malonaticus was also examined.


Efficacy Of Ozone And Ultrasound For Microbial Reduction In Fruit Juice, Sonal Patil Jan 2010

Efficacy Of Ozone And Ultrasound For Microbial Reduction In Fruit Juice, Sonal Patil

Doctoral

Concerns have arisen regarding the microbiological safety of fruit juices due to a number of outbreaks associated with pathogens. Non-thermal technologies for the inactivation of microorganisms are of increasing interest to the food industry for the control of spoilage as well as safety concerns. The objective of this thesis was to investigate the efficacy of ultrasound and ozone treatments for control of microbial issues associated with fruit juices. Inactivation of Escherichia coli (ATCC 25922, NCTC 12900) using power ultrasound was found to be influenced by strain, prior acid adaptation and suspension liquid, but the effect was negated at the higher …


Development Of New Functional Food Applications Of Edible Irish Seaweed, Sabrina Cox Jan 2010

Development Of New Functional Food Applications Of Edible Irish Seaweed, Sabrina Cox

Conference papers

No abstract provided.


Growth And Kinetics Of Lactobacillus Plantarum In The Fermentation Of Edible Irish Brown Seaweeds, Shilpi Gupta, Nissreen Abu-Ghannam, Amalia G.M. Scannell Jan 2010

Growth And Kinetics Of Lactobacillus Plantarum In The Fermentation Of Edible Irish Brown Seaweeds, Shilpi Gupta, Nissreen Abu-Ghannam, Amalia G.M. Scannell

Articles

The aim of the present study was to see the applicability of using brown edible seaweeds as a sole source of nutrition for the growth of lactic acid bacteria. Growth kinetics of lactic acid bacteria (LAB; Lactobacillus plantarum) was studied using three species of edible Irish brown seaweeds Himanthalia elongata, Laminaria digitata and Laminaria saccharina. As part of the screening process, growth of the LAB was carried out on raw and heat treated forms of seaweeds. The seaweed species in their raw state could not support the growth of L. plantarum. Heat treatment resulted in almost 4 times increase in …


Modelling The Growth Inhibition Of Common Food Spoilage And Pathogenic Micro-Organisms In Presence Of Solvent Extract From Irish York Cabbage, Shilpi Gupta, Amit Jaiswal, Nissreen Abu-Ghannam Jan 2010

Modelling The Growth Inhibition Of Common Food Spoilage And Pathogenic Micro-Organisms In Presence Of Solvent Extract From Irish York Cabbage, Shilpi Gupta, Amit Jaiswal, Nissreen Abu-Ghannam

Articles

Preservatives are required to maintain the quality, extend shelf life, and ensure safety of fresh and processed food products. Although chemical preservatives form an essential part in food preservation, legislation has restricted their use in different foods. Vegetables in the Brassica family (Cabbage, Broccoli, Brussels sprouts) are a rich source of a number of bioactive compounds such as flavonoids, glucosinolates and their breakdown products which may have antimicrobial, antioxidant and anticancer properties. The present study investigates the antimicrobial activities of solvent extract from Irish York cabbage, Brocolli and Brussels Sprouts on the growth inhibition of common food spoilage (Listeria monocytogenes …


Inactivation Of Escherichia Coli By Ozone Treatment Of Apple Juice At Different Ph Levels, Sonal Patil, Vasilis Valdramidis, Patrick J. Cullen, Jesus Maria Frias, Paula Bourke Jan 2010

Inactivation Of Escherichia Coli By Ozone Treatment Of Apple Juice At Different Ph Levels, Sonal Patil, Vasilis Valdramidis, Patrick J. Cullen, Jesus Maria Frias, Paula Bourke

Articles

This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (106 CFU mL-1) as a challenge microorganism was treated with ozone at 75-78µg mL-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and juice filtered through 500mm or 1mm sieves. Fast inactivation rates for total reduction of E. coli …


Ozone Inactivation Of Acid Stressed Listeria Monocytogenes And Listeria Innocua In Orange Juice Using A Bubble Column, Sonal Patil, Vasilis Valdramidis, Jesus Maria Frias, Patrick J. Cullen, Paula Bourke Jan 2010

Ozone Inactivation Of Acid Stressed Listeria Monocytogenes And Listeria Innocua In Orange Juice Using A Bubble Column, Sonal Patil, Vasilis Valdramidis, Jesus Maria Frias, Patrick J. Cullen, Paula Bourke

Articles

Orange juice inoculated with Listeria monocytogenes strains ATCC 7644, NCTC 11994 and Listeria innocua NCTC 11288 (106 CFU/ml) as challenge microorganisms was treated with direct ozone at 0.098mg/min/ml for different time periods (0-8 min) using an ozone bubble column. Ozone treatment of mild acid stressed and mild acid stress-habituated (pH 5.5) cells of L. monocytogenes resulted in higher inactivation times compared to control non-acid stressed cells. Additionally acid stressed cells habituated in orange juice (ATCC 7644 & NCTC 11288), showed higher inactivation times during ozonation by comparison with the control as well as the mild-acid stressed cells. Overall the …


Prediction Of Polyphenol Oxidase Activity Using Visible Near-Infrared Hyperspectral Imaging On Mushroom (Agaricus Bisporus) Caps., Edurne Gaston, Jesus Maria Frias, Patrick J. Cullen, Colm O'Donnell, Aoife Gowen Jan 2010

Prediction Of Polyphenol Oxidase Activity Using Visible Near-Infrared Hyperspectral Imaging On Mushroom (Agaricus Bisporus) Caps., Edurne Gaston, Jesus Maria Frias, Patrick J. Cullen, Colm O'Donnell, Aoife Gowen

Articles

Physical stress (i.e. bruising) during harvesting, handling and transportation triggers enzymatic discoloration of mushrooms, a common and detrimental phenomenon largely mediated by polyphenol oxidase (PPO) enzymes. Hyperspectral imaging (HSI) is a non-destructive technique that combines imaging and spectroscopy to obtain information from a sample. The objective of this study was to assess the ability of HSI to predict the activity of PPO on mushroom caps. Hyperspectral images of mushrooms subjected to various damage treatments were taken, followed by enzyme extraction and PPO activity measurement. Principal component regression (PCR) models (each with 3 PCs) built on raw reflectance and multiple scatter …


Substrate Profiling And Aldehyde Dismutase Activity Of The Kvβ2 Subunit Of The Mammalian Kv1 Potassium Channel, A. Kumari, Barry Ryan, J. Dolly, Gary Henehan Jan 2010

Substrate Profiling And Aldehyde Dismutase Activity Of The Kvβ2 Subunit Of The Mammalian Kv1 Potassium Channel, A. Kumari, Barry Ryan, J. Dolly, Gary Henehan

Articles

Voltage-dependent potassium channels (Kv) are involved in various cellular signalling processes by governing the membrane potential of excitable cells. The cytosolic face of these α subunit-containing channels is associated with β subunits that can modulate channel responses. Surprisingly, the β subunit of the mammalian Kv1 channels, Kvβ2, has a high level of sequence homology with the aldo-keto reductase (AKR) superfamily of proteins. Recent studies have shown that Kvβ2 can catalyze the reduction of aldehydes and, most significantly, that channel function is modulated when Kvβ2-bound NADPH is concomitantly oxidized. As a result, the redox chemistry of this subunit is crucial to …


Postharvest Hardness And Color Evolution Of White Button Mushrooms (Agaricus Bisporus)., Debabandya Mohapatra, Zuberi M. Bira, Joseph Kerry, Jesus Maria Frias, Fernanda A.R. Oliveira Jan 2010

Postharvest Hardness And Color Evolution Of White Button Mushrooms (Agaricus Bisporus)., Debabandya Mohapatra, Zuberi M. Bira, Joseph Kerry, Jesus Maria Frias, Fernanda A.R. Oliveira

Articles

The quality evaluation of mushrooms was studied by storing fresh white button mushroom (Agaricus bisporus) for 6-8 days, at various controlled temperature conditions (3.5 -15°C) and measuring the instrumental textural hardness and color of the mushroom cap for different product batches. A non linear mixed effect weibull model was used to describe mushroom cap texture and color kinetics during storage considering the batch variability into account. Storage temperature was found to play a significant role in controlling texture and colour degradation. On lowering storage temperature i) the extent of the final browning extent in the mushroom after storage …


Characterization Of Phenolics Composition In Lamiaceae Spices By Lc-Esi-Ms/Ms, Mohammad Hossain, Dilip Rai, Nigel Brunton, Ana Belen Martin-Diana, Catherine Barry-Ryan Jan 2010

Characterization Of Phenolics Composition In Lamiaceae Spices By Lc-Esi-Ms/Ms, Mohammad Hossain, Dilip Rai, Nigel Brunton, Ana Belen Martin-Diana, Catherine Barry-Ryan

Articles

A total of 38 phenolic compounds in the solid/liquid extracts of five Lamiaceae spices such as 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. In case of unavailability of standards, phenolic compounds were identified based on accurate mass of pseudomolecular [M-H]- ions and …


Study Of The Microbial Diversity And Antimicrobial Properties Of Irish Edible Brown Seaweeds, Shilpi Gupta, Gaurav Rajauria, Nissreen Abu-Ghannam Jan 2010

Study Of The Microbial Diversity And Antimicrobial Properties Of Irish Edible Brown Seaweeds, Shilpi Gupta, Gaurav Rajauria, Nissreen Abu-Ghannam

Articles

Brown Irish edible seaweeds, Himanthalia elongata, Laminaria sachharina and Laminaria digitata, were evaluated for the microbiota in raw and heat processed form. Raw seaweeds showed complete absence of aerobic mesophiles, halophiles, yeasts and molds. However, heating at 85 C for 15 min resulted in spore germination. Bacterial counts as high as 107 were observed for aerobic mesophiles and halophiles. Heating above 95 C for 15 min resulted in complete inactivation of surface microflora. Bacteria belonging to Bacillaceae, Paenibacillaceae, Moraxellaceae and Enterobacteriaceae family were identified by 16S rRNA sequencing. In vitro antimicrobial activity of the methanolic extracts of the seaweed on …


Visible Near-Infrared Hyperspectral Imaging For The Identification And Discrimination Of Brown Blotch Disease On Mushroom (Agaricus Bisporus) Caps, Edurne Gaston, Jesus Maria Frias, Patrick J. Cullen, Colm O’Donnell, Aoife Gowen Jan 2010

Visible Near-Infrared Hyperspectral Imaging For The Identification And Discrimination Of Brown Blotch Disease On Mushroom (Agaricus Bisporus) Caps, Edurne Gaston, Jesus Maria Frias, Patrick J. Cullen, Colm O’Donnell, Aoife Gowen

Articles

Brown blotch, caused by pathogenic Pseudomonas tolaasii (P. tolaasii), is the most problematic bacterial disease in Agaricus bisporus mushrooms. Although it does not cause any health problems, it reduces the consumer appeal of mushrooms in the market place, generating important economical losses worldwide. Hyperspectral imaging (HSI) is a non-destructive technique that combines imaging and spectroscopy to obtain information from a sample. The objective of this study was to investigate the use of HSI for brown blotch identification and discrimination from mechanical damage on mushrooms. Hyperspectral images of mushrooms subjected to i) no treatment, ii) mechanical damage or iii) …


Use Of Fourier Transform Infrared Spectroscopy And Chemometric Data Analysis To Evaluate Damage And Age In Mushrooms (Agaricus Bisporus) Grown In Ireland, Aoife O'Gorman, Gerard Downey, Aoife Gowen, Catherine Barry-Ryan, Jesus Maria Frias Jan 2010

Use Of Fourier Transform Infrared Spectroscopy And Chemometric Data Analysis To Evaluate Damage And Age In Mushrooms (Agaricus Bisporus) Grown In Ireland, Aoife O'Gorman, Gerard Downey, Aoife Gowen, Catherine Barry-Ryan, Jesus Maria Frias

Articles

The aim of this research was to investigate whether the chemical changes induced by mechanical damage and aging of mushrooms can be (a) detected in the mid-infrared absorption region and (b) identified using chemometric data analysis. Mushrooms grown under controlled conditions were bruise-damaged by vibration to simulate damage during normal transportation. Damaged and non-damaged mushrooms were stored for up to 7 days post-harvest. Principal component analysis of FTIR spectra showed evidence that physical damage had an effect on tissue structure and the aging process. Random forest classification models were used to predict damage in mushrooms producing models with error rates …


Effect Of Drying Method On The Antioxidant Capacity Of Six Larniaceae Herbs, M. Hossain, Catherine Barry-Ryan, Ana Belen Martin-Diana, N. Brunton Jan 2010

Effect Of Drying Method On The Antioxidant Capacity Of Six Larniaceae Herbs, M. Hossain, Catherine Barry-Ryan, Ana Belen Martin-Diana, N. Brunton

Articles

The present study investigated the changes in total phenols (TP), rosmarinic acid content and antioxidant capacity of six Lamiaceae herbs (rosemary, oregano, marjoram, sage, basil and thyme) after three drying treatments (air-, freeze- and vacuum oven-drying) stored for 60 days at −20 °C and compared to fresh samples. Ferric reducing antioxidant property (FRAP) and oxygen radical absorbance capacity (ORAC) were used as markers for antioxidant capacity. Air-dried samples had significantly (p < 0.05) higher TP, rosmarinic acid content and antioxidant capacity than had freeze-dried and vacuum oven-dried samples throughout the storage period. Fresh samples had the lowest values for the parameters tested. Vacuum oven-drying resulted in higher TP and FRAP values in rosemary and thyme during 60 days of storage than did freeze-drying. In ORAC assay, the difference was significantly higher only in thyme. Storage did not show any effect on the dried samples for the parameters tested.


Enzymatic Synthesis Of Galactooligosaccharides From Whey Permeate, Federica Manucci Jul 2009

Enzymatic Synthesis Of Galactooligosaccharides From Whey Permeate, Federica Manucci

Masters

Galactooligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut. GOS are commonly produced from lactose in a reaction catalysed by β-galactosidase, termed transglycosylation. In the present work the synthesis of GOS from Whey Permeate (WP) using commercially available β-galactosidases was studied. The enzymes used were from Kluyveromyces lactis (Maxilact® L2000) and Escherichia coli. Initially, a novel quantitative TLC-based assay to monitor GOS synthesis was developed. This method was employed for kinetic analysis but precision and bias problems in quantification were observed. An HPLC assay was subsequently developed …


The Effects Of Acid Adaptation On Escherichia Coli Inactivation Using Power Ultrasound, Sonal Patil, Paula Bourke, Bridget Cullen, Jesus Maria Frias, Patrick J. Cullen Jul 2009

The Effects Of Acid Adaptation On Escherichia Coli Inactivation Using Power Ultrasound, Sonal Patil, Paula Bourke, Bridget Cullen, Jesus Maria Frias, Patrick J. Cullen

Articles

Inactivation of Escherichia coli in liquids was carried out using power ultrasound. Parameters examined included amplitude levels (0.4µm, 7.5 µm, 37.5 µm), treatment time, cell condition (non-adapted cells, acid adapted cells), liquid media (TSB, model orange juice and model apple juice) and E. coli strain (ATCC 25922, NCTC 12900). The efficacy of ultrasound treatment was found to be a function of amplitude level, treatment time and media (p0.95), with the highest inactivation achieved using an amplitude of 37.5 µm. The D-values of E. coli 25922 at all amplitudes in model orange juice were not significantly different than in TSB media. …


Modelling Browning And Brown Spotting Of Mushrooms (Agaricus Bisporus) Stored In Controlled Environmental Conditions Using Image Analysis, Catherine Barry-Ryan, Jesus Maria Frias, Leixuri Aguirre, Helen Grogan Jul 2009

Modelling Browning And Brown Spotting Of Mushrooms (Agaricus Bisporus) Stored In Controlled Environmental Conditions Using Image Analysis, Catherine Barry-Ryan, Jesus Maria Frias, Leixuri Aguirre, Helen Grogan

Articles

Mushrooms have a short postharvest shelf life compared to most vegetables, due to a very high metabolic activity and high water content, making them prone to microbial spoilage and to exhibit enzymatic browning. Storage conditions and natural product variability are both important factors that affect the management of mushrooms, and both of them can be managed using monitoring systems. In order to study the effect of the temperature and relative humidity on the whiteness decrease and appearance of brown spotting, an image analysis system was employed. Twenty five batches of mushrooms were subjected to combinations of three storage temperatures (T) …


Orange Juices Enriched With Chitosan: Optimisation For Extending The Shelf-Life, Catherine Barry-Ryan, Ana Belen Martin-Diana, Daniel Rico, J. Barat Jul 2009

Orange Juices Enriched With Chitosan: Optimisation For Extending The Shelf-Life, Catherine Barry-Ryan, Ana Belen Martin-Diana, Daniel Rico, J. Barat

Articles

Optimisation of the incorporation of chitosan in orange juice was accomplished by the evaluation of quality and nutritional markers. Response surface methodology was applied to obtain quadratic and second degree response surface model equations. The analyses showed that increases in chitosan concentration extended the quality of the orange juice significantly (p < 0.05), reducing enzymatic and non-enzymatic browning and controlling the spoilage during the storage time; however, concentrations N 1 g L− 1 produced a significant (p < 0.05) reduction in the concentrations of ascorbic acid and carotenoids associated with the positive charge of chitosan and its ability to flocculate and coagulate negatively charged substances. Also, concentrations N 1 g L− 1 were scored as unacceptable for the sensory panel due to an increase in bitterness. The study recommends the use of chitosan at concentrations up to 1 g L− 1 to extend quality and preserve ascorbic acid and carotenoids during storage time of fresh orange juice, thus avoiding the use of standard thermal treatments which produces a negative impact on the nutritional value. Industrial relevance: One of the major problems of fresh orange juice is its limited shelf-life. Spoilage and quick degradation of vitamins are two of the most important causes of quality loss during the shelf-life of this product. Moreover, the U. S. Food and Drug Administration issued a warning to consumers against drinking unpasteurised orange juice products because of the potential contamination with Salmonella typhimurium and its association with an outbreak of human disease caused by this organism [FDA issues nationwide health alert on Orchid Island unpasteurised orange juice. Products Recalls, Market Withdrawals and Safety Alerts.]. The main objective of this study was the study of chitosan as a natural preservative for extending the shelf-life of orange juice and as an alternative to pasteurisation.


Identification Of Volatile Quality Markers Of Ready-To-Use Lettuce And Cabbage, Catherine Barry-Ryan, Michael Devereux, Julien Lonchamp Jul 2009

Identification Of Volatile Quality Markers Of Ready-To-Use Lettuce And Cabbage, Catherine Barry-Ryan, Michael Devereux, Julien Lonchamp

Articles

Volatile emission changes of ready-to-use vegetables directly result from minimal processing and can reflect the sensory changes occurring in the product. Based on the detection of key volatile compounds, novel on-line and consumer quality-monitoring methods can be developed. The aim of this study was to identify volatile biomarkers for a range of leafy green ready-to-use vegetables (Butterhead and Iceberg lettuce and Irish York cabbage). Headspace volatile compounds were monitored using gas chromatography/mass spectrometry (GC/MS). The sensory quality of the products was evaluated at days 1, 7 and 14 using sensory and analytical measurements. Changes of volatile concentrations and sensory attributes …


Impact Of Plant Essential Oils On Microbiological, Organoleptic And Quality Markers Of Minimally Processed Vegetables, Jorge Gutierrez, Paula Bourke, Julien Lonchamp, Catherine Barry-Ryan Apr 2009

Impact Of Plant Essential Oils On Microbiological, Organoleptic And Quality Markers Of Minimally Processed Vegetables, Jorge Gutierrez, Paula Bourke, Julien Lonchamp, Catherine Barry-Ryan

Articles

The objectives of this study were to evaluate the efficacy of plant essential oils (EOs) for control of the natural spoilage microflora on ready-to-eat (RTE) lettuce and carrots whilst also considering their impact on organoleptic properties. Initial decontamination effects achieved using EOs were comparable to that observed with chlorine and solution containing oregano recorded a significantly lower initial TVC level than the water treatment on carrots (p < 0.05). No significant differences were found between the EO treatments and chlorine considering gas composition, color, texture and water activity of samples. The sensory panel found EO treatments acceptable for carrots throughout storage, while lettuce washed with the EO solutions were rejected for overall appreciation by Day 7. Correlating microbial and sensory changes with volatile emissions identified 12 volatile quality markers. Oregano might be a suitable decontamination alternative to chlorine for RTE carrots, while the identification of volatile quality markers is a useful complement to sensory and microbiological assessments in the monitoring of organoleptic property changes and shelf-life of fresh vegetables. Industrial relevance There is industrial demand for natural alternatives to chlorine, which is commonly used for decontamination of fresh produce but which has limitations with respect to antimicrobial efficacy and possible formation of carcinogenic compounds in water. Plant essential oils have proven antimicrobial and other bioactive properties, however their usefulness in foods can be mitigated by their high sensory impact. This study examined the application of EOs for fresh produce decontamination addressing control of spoilage microflora and improving shelf-life characteristics whilst also considering the impact on organoleptic properties. The effectiveness of oregano as a decontamination treatment was comparable with that of chlorine. Carrot discs treated with the EO regimes were acceptable in terms of sensory quality and appreciation, therefore oregano could offer a natural alternative for the washing and preservation of fresh produce. Combining EOs with other natural preservatives might minimize doses and reduce the impact on organoleptic properties of fresh vegetables.