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Full-Text Articles in Life Sciences

Determination Of The Effect Of Dairy Powders On Adherence Of Streptococcus Sobrinus And Streptococcus Salivarius To Hydroxylapatite And Growth Of These Bacteria, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan Dec 2010

Determination Of The Effect Of Dairy Powders On Adherence Of Streptococcus Sobrinus And Streptococcus Salivarius To Hydroxylapatite And Growth Of These Bacteria, Rachel Halpin, D.B. Brady, E.D. O’Riordan, M. O’Sullivan

Articles

Dental caries is a highly prevalent disease caused by colonisation of tooth surfaces by cariogenic bacteria, such as Streptococcus sobrinus and Streptococcus salivarius. Reducing initial adherence of such bacteria to teeth may delay onset of caries. Many foods, such as milk, can inhibit microbial adherence. In this investigation, the effect of untreated (UT) and enzyme-treated (ET) dairy powders on adherence of S. sobrinus and S. salivarius to hydroxylapatite (HA), an analogue of tooth enamel, was examined. Untreated (UT) acid whey protein concentrate (AWPC) 80 inhibited streptococcal adherence to phosphate-buffered saline-coated HA (PBS-HA) and saliva-coated HA (S-HA) by >80% at …


Growth Inhibition Of Common Food Spoilage And Pathogenic Microorganisms In The Presence Of Brown Seaweed Extracts, Shilpi Gupta, Sabrina Cox, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam Dec 2010

Growth Inhibition Of Common Food Spoilage And Pathogenic Microorganisms In The Presence Of Brown Seaweed Extracts, Shilpi Gupta, Sabrina Cox, Gaurav Rajauria, Amit Jaiswal, Nissreen Abu-Ghannam

Articles

The possibility of using extracts from brown seaweed, Himanthalia elongata, as a natural antimicrobial agent for food preservation is presented. The effect of different concentrations of seaweed extract on the growth kinetics of four common food spoilage (Pseudomonas aeruginosa and Enterococcus faecalis) and food pathogenic micro-organisms (Listeria monocytogenes and Salmonella abony) was examined. Seaweed extract at a concentration of 6% inhibited the growth of all four of the studied organisms. Lower concentrations of seaweed extract prolonged the lag phase and reduced both the exponential growth rate and final population densities of the culture. Suitability of three kinetic models, Baranyi-Roberts, Modified …


Metabolic Profiling And Fingerprinting For The Detection And Discrimination Of Mechanical Damage In Mushrooms (Agaricus Bisporus) During Storage, Aoife O'Gorman Oct 2010

Metabolic Profiling And Fingerprinting For The Detection And Discrimination Of Mechanical Damage In Mushrooms (Agaricus Bisporus) During Storage, Aoife O'Gorman

Doctoral

Horticultural products such as mushrooms are exposed to external agents during their postharvest life, which are going to affect product quality. Loss of whiteness during storage is particularly important in the mushroom industry. Rough handling and distribution of crops, fruiting body senescence, bacterial and viral infection are among the causes of mushroom discolouration. The aim of this work was to study the use of metabolic fingerprinting and metabolic profiling tools for the detection and discrimination of mechanical damage on mushrooms. This research involved: 1. Investigating whether the chemical changes induced by mechanical damage and ageing of mushrooms could be (a) …


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.


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.


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 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 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 …


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.


Quality And Safety Assessment During The Ozonation Of Cloudy Apple Juice, Sonal Patil, B. Torres, Brijesh Tiwari, Hilda Wingaard, Paula Bourke, Patrick 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 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 …


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 …


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 …


Inactivation Of Escherichia Coli By Ozone Treatment Of Apple Juice At Different Ph Levels, Sonal Patil, Vasilis Valdramidis, Patrick 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 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 …