Ian Fisk | University of Nottingham (original) (raw)

Papers by Ian Fisk

European Food Research and Technology, 2012

The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on t... more The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on the micro-structure (as measured by X-ray micro-Computed Tomography, X-ray lCT) and aroma compound distribution (as measured by HPLC) within shortcake biscuits. X-ray lCT scanning showed biscuits made with PG had smaller pores and higher porosity than biscuits made with TA. Vanillin distribution across the biscuits was not homogeneous and was found at higher concentrations in the centre of the biscuits than the edge or bottom. The baked aroma compound 5-hydroxymethyl-furfural (HMF) was present at higher concentrations at the surface of the biscuits where Maillard chemistry is presumed to occur at its highest rate. The type of solvent had a significant effect on the total concentration and distribution of aroma compounds (p \ 0.05). TA biscuits retained greater vanillin and more HMF was formed during baking when compared to PG biscuits. The core of TA biscuits had (on a relative scale) a much greater vanillin and lower HMF concentration than PG biscuits when compared to their periphery. Although this may be due to different physicochemical properties of the two solvents and varying levels of interactions with other ingredients, the micro-structure differences indicated by X-ray lCT image analysis illustrate one potential route by which the flavour solvent may be influencing the generation and stability of biscuit aroma compounds.

Food Hydrocolloids, 2016

Probiotic incorporation in edible films and coatings has been shown recently to be an efficient s... more Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91-1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate - rice starch based films offering the most enhanced stability. The film's shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.

Food and Bioprocess Technology, 2013

Three different milk proteinsskim milk powder (SMP), sodium caseinate (SC) and whey protein conce... more Three different milk proteinsskim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC)were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, D-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4°C, 25°C and 35°C and the loss of viability calculated. The highest survival rates were obtained at 4°C, inactivation rates for storage were dependent on the carrier wall material and the SMP/D-glucose powders had the lowest inactivation rates (0.013 day −1 ) whilst the highest was observed for the control containing only MD (0.041 day −1 ) and the SC-based system (0.030 day −1 ). Further increase in storage temperature (25°C and 35°C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. D-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems.

Food Chemistry, 2014

The concept of prebiotic edible films as effective vehicles for encapsulating probiotic living ce... more The concept of prebiotic edible films as effective vehicles for encapsulating probiotic living cells is presented. Four soluble fibres (inulin, polydextrose, glucose-oligosaccharides and wheat dextrin) were selected as prebiotic co-components of gelatine based matrices plasticised with glycerol and used for the immobilisation of Lactobacillus rhamnosus GG. The addition of prebiotics was associated with a more compact and uniform film structure, with no detectable interspaces or micropores; probiotic inclusion did not significantly change the structure of the films. Glucose-oligosaccharides and polydextrose significantly enhanced L. rhamnosus GG viability during air drying (by 300% and 75%, respectively), whilst a 33% and 80% reduction in viable counts was observed for inulin and wheat dextrin. Contrarily, inulin was the most effective at controlling the sub-lethal effects on L. rhamnosus GG during storage. However, in all cases the supplementation of edible films with prebiotics ameliorated the storage stability of L. rhamnosus GG.

Journal of the science of food and agriculture, 2014

BACKGROUNDLipids are minor components of flours, but are major determinants of baking properties ... more BACKGROUNDLipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).Lipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).RESULTSFor wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).For wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).CONCLUSIONIn general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches). © 2013 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.In general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches). © 2013 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Food research international (Ottawa, Ont.), 2013

Entrapment of a volatile lipophilic aroma compound (D-limonene) in spray dried waterwashed oil bo... more Entrapment of a volatile lipophilic aroma compound (D-limonene) in spray dried waterwashed oil bodies naturally derived from sunflower seeds (Helianthus annus)

Oilseeds store energy as triacylglycerides during periods of dormancy in preparation for germinat... more Oilseeds store energy as triacylglycerides during periods of dormancy in preparation for germination and the early stages of development, The triacylglyceride is stored in discrete organelles termed oil bodies. Oil bodies are formed during the synthesis of neutral lipids within the bilayer of cellular endoplasmic reticulum (ER) as lipid is synthesised it forms droplets of oil that swell distending the ER membrane and at a critical diameter separate from the ER by vesiculation forming independent organelles.

Abstract: The present invention relates to improvements in the preparation of beverage and food p... more Abstract: The present invention relates to improvements in the preparation of beverage and food products and, in particular, to an improved composition for preparing beverage and food products in machines. The composition is 10 prepared by the addition of a liquid to said composition and comprises one or more beverage or food ingredients and at least one preparation aid.

Abstract: The present invention relates to improvements in the preparation of beverages and, in p... more Abstract: The present invention relates to improvements in the preparation of beverages and, in particular, to an improved cartridge for preparing beverages in brewing machines. The cartridges can also be used for preparing liquid food products.

Abstract The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was... more Abstract The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was investigated during accelerated shelf life (ASL) testing of shortcake biscuits. Specifically, the differential effect on the stability of added vanillin, the natural baked marker compound 5-(hydroxymethyl) furfural (HMF), specific markers of oxidative rancidity (2, 4-decadienal, 2, 4-heptadienal), and the structural parameters of hardness and fracturability.

Abstract Oil bodies (0.1–2.5 µm in diameter) are present in oilseeds, and their principle role is... more Abstract Oil bodies (0.1–2.5 µm in diameter) are present in oilseeds, and their principle role is to store neutral lipids prior to their mobilisation during germination (Huang, 1992; Murphy, 2001). Oats are relatively enriched in oil (3-12% of dry grain mass), but is the oil in-vivo packaged in a similar way to the oil within oilseeds? Although researchers using microscopy have observed spherical droplets of lipid rich material in oat grain no one has analysed these entities ex-vivo.

Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to inves... more Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.Practical ApplicationsSodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.Sodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.

European Food Research and Technology , 2012

The release of volatile compounds, such as aroma, from a food material during hydration is of wid... more The release of volatile compounds, such as aroma, from a food material during hydration is of wide relevance to the food industry. To this end, dry powders of varying chemical composition were hydrated in a controlled system to investigate the impact of varying composition (protein, lipid and carbohydrate) on the delivery rate of volatile compounds to the headspace. Additional lipid and carbohydrate reduced the concentration of volatile compounds in the headspace and accelerated their rate of delivery to the headspace. Protein had no measurable impact. Of the volatile compounds measured, 2,3 butanedione and acetaldehyde were shown to be released slowly into the headspace, and pyrrol, methyl acetate and pyridine were released rapidly; this differential release rate was strongly correlated with hydrophobicity and would indicate that during hydration there is a temporal dimension to the relative abundance of volatile compounds in the headspace.

Journal of the American Oil Chemists' Society , 2012

We describe a procedure for isolating and purifying oil bodies (OBs) from Oryza sativa bran, and ... more We describe a procedure for isolating and purifying oil bodies (OBs) from Oryza sativa bran, and present evidence that strongly suggests a physical association between the OB organelles and several antioxidant phytochemicals (γ-oryzanol and several tocochromanols). This suggestion arises from work showing that despite comprehensive washing steps (9 M urea, water), the majority of the tocotrienols and tocopherols (77 and 73 %, respectively) and oryzanols (91 %) remain integral to the oil bodies, not being released unless the latter are sacrificed. This in turn provides a valuable comparison with similar analyses of tocochromanols in other plant species, as well as indicating that rice bran, normally a waste product from the rice industry, may provide a valuable source of antioxidants as well as protein and unsaturated fat.

Food Research International, 2012

The extraction yield of cafestol from roast and ground (R&G) coffee beans was evaluated using bre... more The extraction yield of cafestol from roast and ground (R&G) coffee beans was evaluated using brews prepared by four brewing mechanisms (boiled, Turkish, French Press and Mocha Pot). The cafestol content of the R&G coffee and the resulting brews was measured and extraction yield calculated. The R&G coffee had an average cafestol content of 603 mg/100 g R&G coffee with a slight reduction at higher roast intensities. In the brews, preparation method had an impact on cafestol concentration with French, Turkish and boiled preparation methods producing the highest cafestol concentrations. The extraction yield of cafestol was shown to be dependent on the brew mechanism and roasting time, with the lightest roast coffee prepared by French press or boiled preparations having the highest cafestol extraction yield (6.5% and 5.84%) and dark roast Mocha and Turkish preparations had the lowest extraction yields of 2.42% and 2.88% respectively.

LWT - Food Science and Technology, 2012

The impact of orange juice pulp on the physical release of limonene to the headspace of freshly p... more The impact of orange juice pulp on the physical release of limonene to the headspace of freshly prepared orange juice was evaluated both in-vitro and in-vivo. Atmospheric pressure chemical ionization mass spectrometry was used to analyse the impact of the matrix on the dynamic release of the volatile aroma compound, limonene, in orange juice. Pulp and aqueous serum was isolated (by centrifugation and filtration) from freshly prepared orange juice and subsequently reconstituted at varying pulp addition levels in serum (0g/100 g–20 g/100 g, wwb). The addition of pulp significantly enhanced the static headspace concentration of limonene with a 210 fold increase with 10 g/100 g pulp addition. In addition, pulp enhanced the ability of the orange juice serum to replenish limonene in the headspace after dynamic headspace dilution. The release of limonene was studied under realistic consumer consumption conditions (In-nose delivery) by atmospheric pressure chemical ionisation-mass spectrometry; pulp significantly enhanced the amount of limonene exhaled in the nasal airflow (retronasal delivery). Surprisingly, given the variations in limonene concentration, naïve consumers did not perceive samples as significantly different on consumption. This is presumably due to the wide range of other aroma compounds not evaluated in this study that contribute to the perceived aroma.

Journal of Cereal Science, 2013

In this paper, we demonstrate a novel and environmentally-conscious approach to the isolation of ... more In this paper, we demonstrate a novel and environmentally-conscious approach to the isolation of oil bodies (OBs) from the bran arising from the milling of Oryza sativa (Basmati rice). We have used several physical techniques to determine the effect of the steps of the process on the OBs, and describe an isolation process that is scalable to an industrial level. The physical techniques [microscopy, particle size determination (diameter 1.9–5.8 μm), ζ-potential (−40 mV at pH 8.0, 0 mV at pH 4.0, 17 mV at pH 2.0), and relative turbidity measurements (pH 3.0–5.0 unstable, pH 6.0–8.0 stable)] and chemical analyses (lipid 83.7%, protein 11.5% dry basis) also give us an insight into the physical properties of OBs in general. This understanding has implications for the use of OBs in food manufacturing, and on the isolation of OBs from a variety of cereal crops.

European Food Research and Technology , 2012

The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on t... more The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on the micro-structure (as measured by X-ray micro-Computed Tomography, X-ray μCT) and aroma compound distribution (as measured by HPLC) within shortcake biscuits. X-ray μCT scanning showed biscuits made with PG had smaller pores and higher porosity than biscuits made with TA. Vanillin distribution across the biscuits was not homogeneous and was found at higher concentrations in the centre of the biscuits than the edge or bottom. The baked aroma compound 5-hydroxymethyl-furfural (HMF) was present at higher concentrations at the surface of the biscuits where Maillard chemistry is presumed to occur at its highest rate. The type of solvent had a significant effect on the total concentration and distribution of aroma compounds (p < 0.05). TA biscuits retained greater vanillin and more HMF was formed during baking when compared to PG biscuits. The core of TA biscuits had (on a relative scale) a much greater vanillin and lower HMF concentration than PG biscuits when compared to their periphery. Although this may be due to different physicochemical properties of the two solvents and varying levels of interactions with other ingredients, the micro-structure differences indicated by X-ray μCT image analysis illustrate one potential route by which the flavour solvent may be influencing the generation and stability of biscuit aroma compounds.

European Food Research and Technology, 2012

The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on t... more The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on the micro-structure (as measured by X-ray micro-Computed Tomography, X-ray lCT) and aroma compound distribution (as measured by HPLC) within shortcake biscuits. X-ray lCT scanning showed biscuits made with PG had smaller pores and higher porosity than biscuits made with TA. Vanillin distribution across the biscuits was not homogeneous and was found at higher concentrations in the centre of the biscuits than the edge or bottom. The baked aroma compound 5-hydroxymethyl-furfural (HMF) was present at higher concentrations at the surface of the biscuits where Maillard chemistry is presumed to occur at its highest rate. The type of solvent had a significant effect on the total concentration and distribution of aroma compounds (p \ 0.05). TA biscuits retained greater vanillin and more HMF was formed during baking when compared to PG biscuits. The core of TA biscuits had (on a relative scale) a much greater vanillin and lower HMF concentration than PG biscuits when compared to their periphery. Although this may be due to different physicochemical properties of the two solvents and varying levels of interactions with other ingredients, the micro-structure differences indicated by X-ray lCT image analysis illustrate one potential route by which the flavour solvent may be influencing the generation and stability of biscuit aroma compounds.

Food Hydrocolloids, 2016

Probiotic incorporation in edible films and coatings has been shown recently to be an efficient s... more Probiotic incorporation in edible films and coatings has been shown recently to be an efficient strategy for the delivery of probiotics in foods. In the present work, the impact of the compositional, physicochemical and structural properties of binary starch-protein edible films on Lactobacillus rhamnosus GG viability and stability was evaluated. Native rice and corn starch, as well as bovine skin gelatine, sodium caseinate and soy protein concentrate were used for the fabrication of the probiotic edible films. Starch and protein type both impacted the structural, mechanical, optical and thermal properties of the films, and the process loss of L. rhamnosus GG during evaporation-dehydration was significantly lower in the presence of proteins (0.91-1.07 log CFU/g) compared to solely starch based systems (1.71 log CFU/g). A synergistic action between rice starch and proteins was detected when monitoring the viability of L. rhamnosus GG over four weeks at fridge and room temperature conditions. In particular, a 3- to 7-fold increase in the viability of L. rhamnosus GG was observed in the presence of proteins, with sodium caseinate - rice starch based films offering the most enhanced stability. The film&amp;amp;amp;amp;amp;amp;#39;s shelf-life (as calculated using the FAO/WHO (2011) basis of 6 log viable CFU/g) ranged between 27-96 and 15-24 days for systems stored at fridge or room temperature conditions respectively.

Food and Bioprocess Technology, 2013

Three different milk proteinsskim milk powder (SMP), sodium caseinate (SC) and whey protein conce... more Three different milk proteinsskim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC)were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, D-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4°C, 25°C and 35°C and the loss of viability calculated. The highest survival rates were obtained at 4°C, inactivation rates for storage were dependent on the carrier wall material and the SMP/D-glucose powders had the lowest inactivation rates (0.013 day −1 ) whilst the highest was observed for the control containing only MD (0.041 day −1 ) and the SC-based system (0.030 day −1 ). Further increase in storage temperature (25°C and 35°C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. D-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems.

Food Chemistry, 2014

The concept of prebiotic edible films as effective vehicles for encapsulating probiotic living ce... more The concept of prebiotic edible films as effective vehicles for encapsulating probiotic living cells is presented. Four soluble fibres (inulin, polydextrose, glucose-oligosaccharides and wheat dextrin) were selected as prebiotic co-components of gelatine based matrices plasticised with glycerol and used for the immobilisation of Lactobacillus rhamnosus GG. The addition of prebiotics was associated with a more compact and uniform film structure, with no detectable interspaces or micropores; probiotic inclusion did not significantly change the structure of the films. Glucose-oligosaccharides and polydextrose significantly enhanced L. rhamnosus GG viability during air drying (by 300% and 75%, respectively), whilst a 33% and 80% reduction in viable counts was observed for inulin and wheat dextrin. Contrarily, inulin was the most effective at controlling the sub-lethal effects on L. rhamnosus GG during storage. However, in all cases the supplementation of edible films with prebiotics ameliorated the storage stability of L. rhamnosus GG.

Journal of the science of food and agriculture, 2014

BACKGROUNDLipids are minor components of flours, but are major determinants of baking properties ... more BACKGROUNDLipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).Lipids are minor components of flours, but are major determinants of baking properties and end-product quality. To the best of our knowledge, there is no single solvent system currently known that efficiently extracts all non-starch lipids from all flours without the risk of chemical, mechanical or thermal damage. This paper compares nine ambient solvent systems (monophasic and biphasic) with varying polarities: Bligh and Dyer (BD); modified Bligh and Dyer using HCl (BDHCL); modified BD using NaCl (BDNaCl); methanol–chloroform–hexane (3:2:1, v/v); Hara and Radin (hexane–isopropanol, 3:2, v/v); water-saturated n-butanol; chloroform; methanol and hexane for their ability to extract total non-starch lipids (separated by lipid classes) from wheat flour (Triticum aestivum L.). Seven ambient extraction protocols were further compared for their ability to extract total non-starch lipids from three alternative samples: barley flour (Hordeum vulgare L.), maize starch (Zea mays L.) and tapioca starch (Manihot esculenta Crantz).RESULTSFor wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).For wheat flour the original BD method and those containing HCl or NaCl tended to extract the maximum lipid and a significant correlation between lipid extraction yield (especially the glycolipids and phospholipids) and the polarity of the solvent was observed. For the wider range of samples BD and BD HCl repeatedly offered the maximum extraction yield and using pooled standardized (by sample) data from all flours, total non-starch lipid extraction yield was positively correlated with solvent polarity (r = 0.5682, P < 0.05) and water ratio in the solvent mixture (r = 0.5299, P < 0.05).CONCLUSIONIn general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches). © 2013 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.In general, BD-based methods showed better extraction yields compared to methods without the addition of water and, most interestingly, there was much greater method dependence of lipid yields in the starches when compared to the flour samples, which is due to the differences in lipid profiles between the two sample types (flours and starches). © 2013 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Food research international (Ottawa, Ont.), 2013

Entrapment of a volatile lipophilic aroma compound (D-limonene) in spray dried waterwashed oil bo... more Entrapment of a volatile lipophilic aroma compound (D-limonene) in spray dried waterwashed oil bodies naturally derived from sunflower seeds (Helianthus annus)

Oilseeds store energy as triacylglycerides during periods of dormancy in preparation for germinat... more Oilseeds store energy as triacylglycerides during periods of dormancy in preparation for germination and the early stages of development, The triacylglyceride is stored in discrete organelles termed oil bodies. Oil bodies are formed during the synthesis of neutral lipids within the bilayer of cellular endoplasmic reticulum (ER) as lipid is synthesised it forms droplets of oil that swell distending the ER membrane and at a critical diameter separate from the ER by vesiculation forming independent organelles.

Abstract: The present invention relates to improvements in the preparation of beverage and food p... more Abstract: The present invention relates to improvements in the preparation of beverage and food products and, in particular, to an improved composition for preparing beverage and food products in machines. The composition is 10 prepared by the addition of a liquid to said composition and comprises one or more beverage or food ingredients and at least one preparation aid.

Abstract: The present invention relates to improvements in the preparation of beverages and, in p... more Abstract: The present invention relates to improvements in the preparation of beverages and, in particular, to an improved cartridge for preparing beverages in brewing machines. The cartridges can also be used for preparing liquid food products.

Abstract The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was... more Abstract The influence of choice of flavour solvent, propylene glycol (PG) or triacetin (TA), was investigated during accelerated shelf life (ASL) testing of shortcake biscuits. Specifically, the differential effect on the stability of added vanillin, the natural baked marker compound 5-(hydroxymethyl) furfural (HMF), specific markers of oxidative rancidity (2, 4-decadienal, 2, 4-heptadienal), and the structural parameters of hardness and fracturability.

Abstract Oil bodies (0.1–2.5 µm in diameter) are present in oilseeds, and their principle role is... more Abstract Oil bodies (0.1–2.5 µm in diameter) are present in oilseeds, and their principle role is to store neutral lipids prior to their mobilisation during germination (Huang, 1992; Murphy, 2001). Oats are relatively enriched in oil (3-12% of dry grain mass), but is the oil in-vivo packaged in a similar way to the oil within oilseeds? Although researchers using microscopy have observed spherical droplets of lipid rich material in oat grain no one has analysed these entities ex-vivo.

Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to inves... more Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.Fried, sliced potato crisps were flavored with sodium chloride of varying size fractions to investigate the impact of salt crystal size on the delivery rate of sodium to the tongue and resultant saltiness, measured over 65 s with a defined chew protocol (three chews, then holding the bolus in the mouth without swallowing). Salt crystal size impacted upon the delivery rate and perceived saltiness. The smallest crystal size fraction dissolved and diffused throughout the mouth to the tongue saliva faster than the medium and the largest ones; the smallest crystal size fraction also had the highest maximum concentration and greatest total sodium. These results correlated well with the sensory perceived saltiness, where the smallest crystal size fraction resulted in the fastest Tmax, highest maximum saltiness intensity and maximum total saltiness. The different delivery rates can be explained by differential dissolution kinetics and enhanced mass transfer of sodium across the saliva.Practical ApplicationsSodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.Sodium reduction is a major challenge for the global food industry. The results of this work illustrate how modification of salt crystal size fraction might impact sensory perceived saltiness, and that a smaller crystal size fraction can achieve a greater maximum saltiness per unit of sodium consumed. There are a number of technical hurdles to be overcome before implementation of this approach, both practical (limitations in processability) and sensorial (changes in the time–intensity profile), but the results do demonstrate that enhanced dissolution and diffusion kinetics can be achieved through modification of salt crystal size, which should be seriously considered by snack food manufacturers when approaching product reformulation.

European Food Research and Technology , 2012

The release of volatile compounds, such as aroma, from a food material during hydration is of wid... more The release of volatile compounds, such as aroma, from a food material during hydration is of wide relevance to the food industry. To this end, dry powders of varying chemical composition were hydrated in a controlled system to investigate the impact of varying composition (protein, lipid and carbohydrate) on the delivery rate of volatile compounds to the headspace. Additional lipid and carbohydrate reduced the concentration of volatile compounds in the headspace and accelerated their rate of delivery to the headspace. Protein had no measurable impact. Of the volatile compounds measured, 2,3 butanedione and acetaldehyde were shown to be released slowly into the headspace, and pyrrol, methyl acetate and pyridine were released rapidly; this differential release rate was strongly correlated with hydrophobicity and would indicate that during hydration there is a temporal dimension to the relative abundance of volatile compounds in the headspace.

Journal of the American Oil Chemists' Society , 2012

We describe a procedure for isolating and purifying oil bodies (OBs) from Oryza sativa bran, and ... more We describe a procedure for isolating and purifying oil bodies (OBs) from Oryza sativa bran, and present evidence that strongly suggests a physical association between the OB organelles and several antioxidant phytochemicals (γ-oryzanol and several tocochromanols). This suggestion arises from work showing that despite comprehensive washing steps (9 M urea, water), the majority of the tocotrienols and tocopherols (77 and 73 %, respectively) and oryzanols (91 %) remain integral to the oil bodies, not being released unless the latter are sacrificed. This in turn provides a valuable comparison with similar analyses of tocochromanols in other plant species, as well as indicating that rice bran, normally a waste product from the rice industry, may provide a valuable source of antioxidants as well as protein and unsaturated fat.

Food Research International, 2012

The extraction yield of cafestol from roast and ground (R&G) coffee beans was evaluated using bre... more The extraction yield of cafestol from roast and ground (R&G) coffee beans was evaluated using brews prepared by four brewing mechanisms (boiled, Turkish, French Press and Mocha Pot). The cafestol content of the R&G coffee and the resulting brews was measured and extraction yield calculated. The R&G coffee had an average cafestol content of 603 mg/100 g R&G coffee with a slight reduction at higher roast intensities. In the brews, preparation method had an impact on cafestol concentration with French, Turkish and boiled preparation methods producing the highest cafestol concentrations. The extraction yield of cafestol was shown to be dependent on the brew mechanism and roasting time, with the lightest roast coffee prepared by French press or boiled preparations having the highest cafestol extraction yield (6.5% and 5.84%) and dark roast Mocha and Turkish preparations had the lowest extraction yields of 2.42% and 2.88% respectively.

LWT - Food Science and Technology, 2012

The impact of orange juice pulp on the physical release of limonene to the headspace of freshly p... more The impact of orange juice pulp on the physical release of limonene to the headspace of freshly prepared orange juice was evaluated both in-vitro and in-vivo. Atmospheric pressure chemical ionization mass spectrometry was used to analyse the impact of the matrix on the dynamic release of the volatile aroma compound, limonene, in orange juice. Pulp and aqueous serum was isolated (by centrifugation and filtration) from freshly prepared orange juice and subsequently reconstituted at varying pulp addition levels in serum (0g/100 g–20 g/100 g, wwb). The addition of pulp significantly enhanced the static headspace concentration of limonene with a 210 fold increase with 10 g/100 g pulp addition. In addition, pulp enhanced the ability of the orange juice serum to replenish limonene in the headspace after dynamic headspace dilution. The release of limonene was studied under realistic consumer consumption conditions (In-nose delivery) by atmospheric pressure chemical ionisation-mass spectrometry; pulp significantly enhanced the amount of limonene exhaled in the nasal airflow (retronasal delivery). Surprisingly, given the variations in limonene concentration, naïve consumers did not perceive samples as significantly different on consumption. This is presumably due to the wide range of other aroma compounds not evaluated in this study that contribute to the perceived aroma.

Journal of Cereal Science, 2013

In this paper, we demonstrate a novel and environmentally-conscious approach to the isolation of ... more In this paper, we demonstrate a novel and environmentally-conscious approach to the isolation of oil bodies (OBs) from the bran arising from the milling of Oryza sativa (Basmati rice). We have used several physical techniques to determine the effect of the steps of the process on the OBs, and describe an isolation process that is scalable to an industrial level. The physical techniques [microscopy, particle size determination (diameter 1.9–5.8 μm), ζ-potential (−40 mV at pH 8.0, 0 mV at pH 4.0, 17 mV at pH 2.0), and relative turbidity measurements (pH 3.0–5.0 unstable, pH 6.0–8.0 stable)] and chemical analyses (lipid 83.7%, protein 11.5% dry basis) also give us an insight into the physical properties of OBs in general. This understanding has implications for the use of OBs in food manufacturing, and on the isolation of OBs from a variety of cereal crops.

European Food Research and Technology , 2012

The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on t... more The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on the micro-structure (as measured by X-ray micro-Computed Tomography, X-ray μCT) and aroma compound distribution (as measured by HPLC) within shortcake biscuits. X-ray μCT scanning showed biscuits made with PG had smaller pores and higher porosity than biscuits made with TA. Vanillin distribution across the biscuits was not homogeneous and was found at higher concentrations in the centre of the biscuits than the edge or bottom. The baked aroma compound 5-hydroxymethyl-furfural (HMF) was present at higher concentrations at the surface of the biscuits where Maillard chemistry is presumed to occur at its highest rate. The type of solvent had a significant effect on the total concentration and distribution of aroma compounds (p < 0.05). TA biscuits retained greater vanillin and more HMF was formed during baking when compared to PG biscuits. The core of TA biscuits had (on a relative scale) a much greater vanillin and lower HMF concentration than PG biscuits when compared to their periphery. Although this may be due to different physicochemical properties of the two solvents and varying levels of interactions with other ingredients, the micro-structure differences indicated by X-ray μCT image analysis illustrate one potential route by which the flavour solvent may be influencing the generation and stability of biscuit aroma compounds.

This work was conducted to study the predictive ability of a range of rapid scanning methodologie... more This work was conducted to study the predictive ability of a range of rapid scanning methodologies to estimate raw material composition and processing variability for freezedried soluble coffee. To this purpose a series of soluble coffee samples were evaluated by a range of techniques (Chemsensor, Raman, FT-IR, NIR) and the resulting individual spectra evaluated for their predictive ability.