The aim of the Food Chemistry & Technology Department is to help food processors maintain competitive advantage and secure premium markets. Our Dairy research focuses on cheese, infant formula and dairy based ingredients; Meat research, focusing on quality, whole chain management and recovering value from meat processing streams; Cereal research focusing on product quality and innovation in the bakery industry

Recent Submissions

  • Investigation of Raman Spectroscopy (with Fiber Optic Probe) and Chemometric Data Analysis for the Determination of Mineral Content in Aqueous Infant Formula

    Zhao, Ming; Shaikh, Saif; Kang, Renxi; Markiewicz-Keszycka, Maria (MDPI AG, 2020-07-22)
    This study investigated the use of Raman spectroscopy (RS) and chemometrics for the determination of eight mineral elements (i.e., Ca, Mg, K, Na, Cu, Mn, Fe, and Zn) in aqueous infant formula (INF). The samples were prepared using infant formula powder reconstituted to concentrations of 3%–13% w/w (powder: water) (n = 83). Raman spectral data acquisition was carried out using a non-contact fiber optic probe on the surface of aqueous samples in 50–3398 cm−1. ICP-AES was used as a reference method for the determination of the mineral contents in aqueous INF samples. Results showed that the best performing partial least squares regression (PLSR) models developed for the prediction of minerals using all samples for calibration achieved R2CV values of 0.51–0.95 with RMSECVs of 0.13–2.96 ppm. The PLSR models developed and validated using separate calibration (n = 42) and validation (n = 41) samples achieved R2CVs of 0.93, 0.94, 0.91, 0.90, 0.97, and 0.94, R2Ps of 0.75, 0.77, 0.31, 0.60, 0.84, and 0.80 with RMSEPs of 3.17, 0.29, 3.45, 1.51, 0.30, and 0.25 ppm for the prediction of Ca, Mg, K, Na, Fe, and Zn respectively. This study demonstrated that RS equipped with a non-contact fiber optic probe and combined with chemometrics has the potential for timely quantification of the mineral content of aqueous INF during manufacturing.
  • WO 2018/114971 A1 A method for producing beads

    Brodkorb, Andre; Haque, Kamrul; Teagasc Agriculture and Food Development Authority (2020-10-19)
    The current invention relates to a method for producing beads. In particular, the current invention relates to a method for producing microbeads. The invention also relates to a microbead preparation produced by the method of the invention.
  • Using a reaction‐diffusion model to estimate day respiration and reassimilation of (photo)respiredCO2in leaves

    Berghuijs, Herman N. C.; Yin, Xinyou; Ho, Q. Tri; Retta, Moges A.; Nicolaï, Bart M.; Struik, Paul C.; the BioSolar Cells programme; Research Council of the KU Leuven; project C16/ 16/002 (Wiley, 2019-05-11)
    Methods using gas exchange measurements to estimate respiration in the light (day respiration Rd) make implicit assumptions about reassimilation of (photo)respired CO2; however, this reassimilation depends on the positions of mitochondria. We used a reaction-diffusion model without making these assumptions to analyse datasets on gas exchange, chlorophyll fluorescence and anatomy for tomato leaves. We investigated how Rd values obtained by the Kok and the Yin methods are affected by these assumptions and how those by the Laisk method are affected by the positions of mitochondria. The Kok method always underestimated Rd. Estimates of Rd by the Yin method and by the reaction-diffusion model agreed only for nonphotorespiratory conditions. Both the Yin and Kok methods ignore reassimilation of (photo)respired CO2, and thus underestimated Rd for photorespiratory conditions, but this was less so in the Yin than in the Kok method. Estimates by the Laisk method were affected by assumed positions of mitochondria. It did not work if mitochondria were in the cytosol between the plasmamembrane and the chloroplast envelope. However, mitochondria were found to be most likely between the tonoplast and chloroplasts. Our reaction-diffusion model effectively estimates Rd, enlightens the dependence of Rd estimates on reassimilation and clarifies (dis)advantages of existing methods.
  • Use of Lactic Acid Bacteria to Reduce Methane Production in Ruminants, a Critical Review

    Doyle, Natasha; Mbandlwa, Philiswa; Kelly, William J.; Attwood, Graeme; Li, Yang; Ross, R. Paul; STANTON, CATHERINE; Leahy, Sinead; European Union; Teagasc Walsh Fellowship Programme; et al. (Frontiers Media SA, 2019-10-01)
    Enteric fermentation in ruminants is the single largest anthropogenic source of agricultural methane and has a significant role in global warming. Consequently, innovative solutions to reduce methane emissions from livestock farming are required to ensure future sustainable food production. One possible approach is the use of lactic acid bacteria (LAB), Gram positive bacteria that produce lactic acid as a major end product of carbohydrate fermentation. LAB are natural inhabitants of the intestinal tract of mammals and are among the most important groups of microorganisms used in food fermentations. LAB can be readily isolated from ruminant animals and are currently used on-farm as direct-fed microbials (DFMs) and as silage inoculants. While it has been proposed that LAB can be used to reduce methane production in ruminant livestock, so far research has been limited, and convincing animal data to support the concept are lacking. This review has critically evaluated the current literature and provided a comprehensive analysis and summary of the potential use and mechanisms of LAB as a methane mitigation strategy. It is clear that although there are some promising results, more research is needed to identify whether the use of LAB can be an effective methane mitigation option for ruminant livestock.
  • Fortified Blended Food Base: Effect of Co-Fermentation Time on Composition, Phytic Acid Content and Reconstitution Properties

    Shevade, Ashwini; O’Callaghan, Yvonne; O’Brien, Nora; O’Connor, Tom; Guinee, Timothy; Department of Agriculture, Food and the Marine; 14/F/805 (MDPI AG, 2019-09-03)
    Dehydrated blends of dairy-cereal combine the functional and nutritional properties of two major food groups. Fortified blended food base (FBFB) was prepared by blending fermented milk with parboiled wheat, co-fermenting the blend at 35 ◦C, shelf-drying and milling. Increasing co-fermentation time from 0 to 72 h resulted in powder with lower lactose, phytic acid and pH, and higher contents of lactic acid and galactose. Simultaneously, the pasting viscosity of the reconstituted base (16.7%, w/w, total solids) and its yield stress (σ0), consistency index (K) and viscosity on shearing decreased significantly. The changes in some characteristics (pH, phytic acid, η120) were essentially complete after 24 h co-fermentation while others (lactose, galactose and lactic acid, pasting viscosities, flowability) proceeded more gradually over 72 h. The reduction in phytic acid varied from 40 to 58% depending on the pH of the fermented milk prior to blending with the parboiled cereal. The reduction in phytic acid content of milk (fermented milk)-cereal blends with co-fermentation time is nutritionally desirable as it is conducive to an enhanced bioavailability of elements, such as Ca, Mg, Fe and Zn in milk-cereal blends, and is especially important where such blends serve as a base for fortified-blended foods supplied to food-insecure regions
  • Online Prediction of Physico-Chemical Quality Attributes of Beef Using Visible—Near-Infrared Spectroscopy and Chemometrics

    Sahar, Amna; Allen, Paul; Sweeney, Torres; Cafferky, Jamie; Downey, Gerard; Cromie, Andrew; Hamill, Ruth; Department of Food, Agriculture and the Marine; 11/SF/311 (MDPI AG, 2019-10-23)
    The potential of visible–near-infrared (Vis–NIR) spectroscopy to predict physico-chemical quality traits in 368 samples of bovine musculus longissimus thoracis et lumborum (LTL) was evaluated. A fibre-optic probe was applied on the exposed surface of the bovine carcass for the collection of spectra, including the neck and rump (1 h and 2 h post-mortem and after quartering, i.e., 24 h and 25 h post-mortem) and the boned-out LTL muscle (48 h and 49 h post-mortem). In parallel, reference analysis for physico-chemical parameters of beef quality including ultimate pH, colour (L, a*, b*), cook loss and drip loss was conducted using standard laboratory methods. Partial least-squares (PLS) regression models were used to correlate the spectral information with reference quality parameters of beef muscle. Different mathematical pre-treatments and their combinations were applied to improve the model accuracy, which was evaluated on the basis of the coefficient of determination of calibration (R2C) and cross-validation (R2CV) and root-mean-square error of calibration (RMSEC) and cross-validation (RMSECV). Reliable cross-validation models were achieved for ultimate pH (R2CV: 0.91 (quartering, 24 h) and R2CV: 0.96 (LTL muscle, 48 h)) and drip loss (R2CV: 0.82 (quartering, 24 h) and R2CV: 0.99 (LTL muscle, 48 h)) with lower RMSECV values. The results show the potential of Vis–NIR spectroscopy for online prediction of certain quality parameters of beef over different time periods.
  • Effect of Diet on the Vitamin B Profile of Bovine Milk-Based Protein Ingredients

    Magan, Jonathan B.; O’Callaghan, Tom F.; Zheng, Jiamin; Zhang, Lun; Mandal, Rupasri; Hennessy, Deirdre; Fenelon, Mark; Wishart, David S.; Kelly, Alan L.; McCarthy, Noel; et al. (MDPI AG, 2020-05-04)
    The influence of diet on the water-soluble vitamin composition of skim milk powder and whey protein ingredients produced from the milk of cows fed pasture or concentrate-based diets was examined. Fifty-one Holstein-Friesian cows were randomly assigned into three diets (n = 17) consisting of outdoor grazing of perennial ryegrass (GRS), perennial ryegrass/white clover (CLV), or indoor feeding of total mixed ration (TMR) for an entire lactation. Raw mid-lactation milk from each group was processed into skim milk powder and further processed to yield micellar casein whey and acid whey. Sweet whey was also produced by renneting of pasteurised whole milk from each system. The water-soluble vitamin profile of each sample was analysed using a combination of direct injection mass spectrometry and reverse-phase liquid chromatography–mass spectrometry. Vitamin B3 and B3-amide concentrations were significantly higher (p < 0.05) in TMR-derived samples than in those from CLV and GRS, respectively. Vitamin B1, B2, and B7 concentrations were significantly higher in GRS and CLV-derived samples than those from TMR. Significant differences in vitamins B1, B2, and B3-amide were also observed between protein ingredient types. This study indicates that bovine feeding systems have a significant effect on B vitamin composition across a range of protein ingredient types.
  • A standardised static in vitro digestion method suitable for food – an international consensus

    Minekus, M.; Alminger, M.; Alvito, P.; Ballance, S.; Bohn, T.; Bourlieu, C.; Carrière, F.; Boutrou, R.; Corredig, M.; Dupont, D.; et al. (Royal Society of Chemistry (RSC), 2014-04-07)
    Simulated gastro-intestinal digestion is widely employed in many fields of food and nutritional sciences, as conducting human trials are often costly, resource intensive, and ethically disputable. As a consequence, in vitro alternatives that determine endpoints such as the bioaccessibility of nutrients and non-nutrients or the digestibility of macronutrients (e.g. lipids, proteins and carbohydrates) are used for screening and building new hypotheses. Various digestion models have been proposed, often impeding the possibility to compare results across research teams. For example, a large variety of enzymes from different sources such as of porcine, rabbit or human origin have been used, differing in their activity and characterization. Differences in pH, mineral type, ionic strength and digestion time, which alter enzyme activity and other phenomena, may also considerably alter results. Other parameters such as the presence of phospholipids, individual enzymes such as gastric lipase and digestive emulsifiers vs. their mixtures (e.g. pancreatin and bile salts), and the ratio of food bolus to digestive fluids, have also been discussed at length. In the present consensus paper, within the COST Infogest network, we propose a general standardised and practical static digestion method based on physiologically relevant conditions that can be applied for various endpoints, which may be amended to accommodate further specific requirements. A frameset of parameters including the oral, gastric and small intestinal digestion are outlined and their relevance discussed in relation to available in vivo data and enzymes. This consensus paper will give a detailed protocol and a line-by-line, guidance, recommendations and justifications but also limitation of the proposed model. This harmonised static, in vitro digestion method for food should aid the production of more comparable data in the future.
  • Dairy cow feeding system alters the characteristics of low-heat skim milk powder and processability of reconstituted skim milk

    Gulati, Arunima; Hennessy, Deirdre; O'Donovan, Michael; McManus, Jennifer J.; Fenelon, Mark; Guinee, Timothy P.; Department of Agriculture, Food and the Marine; Dairy Levy Trust Co-Operative Society Limited; 11/sf/309 (Elsevier for American Dairy Science Association, 2019-08-01)
    Low-heat skim milk powder (LHSMP) was manufactured on 3 separate occasions in mid lactation (ML, July 4–20) and late lactation (LL, September 27 to October 7) from bulk milk of 3 spring-calving dairy herds on different feeding systems: grazing on perennial ryegrass (Lolium perenne L.) pasture (GRO), grazing on perennial ryegrass and white clover (Trifolium repens L.) pasture (GRC), and housed indoors and offered total mixed ration (TMR). The resultant powders (GRO-SMP, GRC-SMP, and TMR-SMP) were evaluated for composition and color and for the compositional, physicochemical, and processing characteristics of the reconstituted skim milk (RSM) prepared by dispersing the powders to 10% (wt/wt) in water. Feeding system significantly affected the contents of protein and lactose, the elemental composition, and the color of the LHSMP, as well as the rennet gelation properties of the RSM. The GRO and GRC powders had a higher protein content; lower levels of lactose, iodine, and selenium; and a more yellow-green color (lower a* and higher b* color coordinates) than TMR powder. On reconstitution, the GRO-RSM had higher concentrations of protein, casein, and ionic calcium, and lower concentrations of lactose and nonprotein nitrogen (% of total N). It also produced rennet gels with a higher storage modulus (G′) than the corresponding TMR-RSM. These effects were observed over the combined ML and LL period but varied somewhat during the separate ML and LL periods. Otherwise, feeding system had little or no effect on proportions of individual caseins, concentration of serum casein, casein micelle size, casein hydration, heat coagulation time, or ethanol stability of the RSM at pH 6.2 to 7.2, or on the water-holding capacity, viscosity, and flow behavior of stirred yogurt prepared by starter-induced acidification of RSM. The differences in the functionality of the LHSMP may be of greater or lesser importance depending on the application and the conditions applied during the processing of the RSM.
  • Integrated phenotypic-genotypic approach to understand the influence of ultrasound on metabolic response of Lactobacillus sakei

    Ojha, K. Shikha; Burgess, Catherine; Duffy, Geraldine; Kerry, Joseph P.; Tiwari, Brijesh K; Teagasc Walsh Fellowship Programme (Public Library of Science (PLoS), 2018-01-25)
    The lethal effects of soundwaves on a range of microorganisms have been known for almost a century whereas, the use of ultrasound to promote or control their activity is much more recent. Moreover, the fundamental molecular mechanism influencing the behaviour of microorganisms subjected to ultrasonic waves is not well established. In this study, we investigated the influence of ultrasonic frequencies of 20, 45, 130 and 950 kHz on growth kinetics of Lactobacillus sakei. A significant increase in the growth rate of L. sakei was observed following ultrasound treatment at 20 kHz despite the treatment yielding a significant reduction of ca. 3 log cfu/mL in cells count. Scanning electron microscopy showed that ultrasound caused significant changes on the cell surface of L. sakei culture with the formation of pores “sonoporation”. Phenotypic microarrays showed that all ultrasound treated L. sakei after exposure to various carbon, nitrogen, phosphorus and sulphur sources had significant variations in nutrient utilisation. Integration of this phenotypic data with the genome of L. sakei revealed that various metabolic pathways were being influenced by the ultrasound treatments. Results presented in this study showed that the physiological response of L. sakei in response to US is frequency dependent and that it can influence metabolic pathways. Hence, ultrasound treatments can be employed to modulate microbial activity for specialised applications.
  • The effect of pre-treatment of protein ingredients for infant formula on their in vitro gastro-intestinal behaviour

    Corrigan, Bernard; Brodkorb, Andre; Kerry Group (Elsevier, 2020-07-27)
    Three milk products, skim milk powder (SMP), demineralised whey powder (DWP) and a whey dominant infant formula (60/40IF) and their corresponding partially hydrolysed products (SMPhyd, DWPhyd and 60/40hyd, respectively) were subjected to static infant in vitro gastro-intestinal (GI) digestion and their digesta were subsequently analysed for protein breakdown. The pre-hydrolysis of proteins provided a head-start in the gastric digestion process compared with the intact proteins, resulting in a higher proportion of small peptides (<1 kDa), a higher degree of hydrolysis and lower observable protein coagulation or curd formation in the gastric phase of the casein dominant systems in particular, which may lead to an earlier onset of gastric emptying in vivo. Little or no differences were detected during the intestinal phase. Hence pre-hydrolysis of proteins may be used as a strategy to lower gastric transit times, which may ease the gastric digestion of infant formulations.
  • The effect of high velocity steam injection on the colloidal stability of concentrated emulsions for the manufacture of infant formulations

    Murphy, Eoin; Tobin, John; Roos, Yrjo H.; Fenelon, Mark (Elsevier BV, 2011)
    A major challenge for the infant formula industry is to develop more energy efficient processes while maintaining product quality and robust manufacturing practices. An effective way of improving energy utilisation is to reduce the number of processing steps during manufacture. This study examines a novel high solids process with reduced processing steps paying particular attention to emulsion stability. Model infant formulations (whey to casein ratio, 60:40) were homogenised at a solids content of 60% w/w using an in-line colloid-mill type mixer, yielding a stable emulsion with a fat globule size distribution (D(v,0.9)) of 2.99 colonm. These formulations were heat-treated using a high velocity direct steam injection device, whereby steam is accelerated using a De Laval nozzle before injection. The steam condenses on contact with the formulation, giving up latent heat, thus heating the mix. The process was found to increase the colloidal stability of the formulations, as measured in an analytical centrifuge. The fat globule size distribution was significantly (p < 0.05) decreased to 2.69 μm after processing by the injector with a concomitant significant (p < 0.05) increase in emulsion viscosity. In conclusion, in-line homogenisation followed by high velocity steam injection, using a De Laval geometry, was successfully used for heat treatment of a high solids infant formulation.
  • The effect of high velocity steam injection on the colloidal stability of concentrated emulsions for the manufacture of infant formulations

    Murphy, Eoin; Tobin, John; Roos, Yrjo H.; Fenelon, Mark (Elsevier, 2011-12-28)
    A major challenge for the infant formula industry is to develop more energy efficient processes while maintaining product quality and robust manufacturing practices. An effective way of improving energy utilisation is to reduce the number of processing steps during manufacture. This study examines a novel high solids process with reduced processing steps paying particular attention to emulsion stability. Model infant formulations (whey to casein ratio, 60:40) were homogenised at a solids content of 60% w/w using an in-line colloid-mill type mixer, yielding a stable emulsion with a fat globule size distribution (D(v,0.9)) of 2.99 colonm. These formulations were heat-treated using a high velocity direct steam injection device, whereby steam is accelerated using a De Laval nozzle before injection. The steam condenses on contact with the formulation, giving up latent heat, thus heating the mix. The process was found to increase the colloidal stability of the formulations, as measured in an analytical centrifuge. The fat globule size distribution was significantly (p < 0.05) decreased to 2.69 μm after processing by the injector with a concomitant significant (p < 0.05) increase in emulsion viscosity. In conclusion, in-line homogenisation followed by high velocity steam injection, using a De Laval geometry, was successfully used for heat treatment of a high solids infant formulation.
  • Modelling inactivation of Staphylococcus spp. on sliced Brazilian dry-cured loin with thermosonication and peracetic acid combined treatment

    Rosario, Denes K.A.; Bernardo, Yago A.A.; Mutz, Yhan S.; Tiwari, Brijesh K; Rajkovic, Andreja; Bernardes, Patricia C.; Conte-Junior, Carlos A.; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Científico e Tecnológico; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; et al. (Elsevier, 2019-08-26)
    Ultrasound (US) has a high capacity to increase food safety. Although high and/or moderate temperature in combination with US has been studied, the knowledge about cooling/low temperatures as well as its combined effect with chemical preservation methods is scarce. Therefore, the aim of this study was to describe the inactivation of Staphylococcus spp. (SA) present in the natural microbiota of sliced Brazilian dry-cured loin (BDL) using US (40 kHz and 5.40 W/g) at 1.6–17.9 kJ/g, temperature (T) between 6.4 and 73.6 °C and peracetic acid (PA) between 5.5 and 274.5 mg/L employing the Central Composite Rotatable Design. The model fully describes how the combination of US, T, and PA affects SA inactivation. In BDL, an increase in US acoustic energy density (kJ/g) allows the reduction of T necessary to inactivate SA because of the occurrence of synergistic effect. However, US applied at low T was inefficient. On the other hand, PA was more efficient at low T, since high T degraded this compound at different rates according to the holding T. Therefore, the data indicates a relation between the technologies used in the combined decontamination of sliced BDL improving dry-cured meat safety.
  • Physicochemical properties of whole milk powder derived from cows fed pasture or total mixed ration diets

    Magan, Jonathan B.; Tobin, John; O'Callaghan, Tom; Kelly, Alan L.; Fenelon, Mark; Hennessy, Deirdre; McCarthy, Noel; Teagasc Walsh Fellowship Programme; The Irish Dairy Levy; MDDT0044 (Elsevier, 2019-08-22)
    This study examined the effect of dietary factors on compositional and functional properties of whole milk powder (WMP) produced from bovine milk. Raw milk samples were obtained from 3 groups of 18 Holstein Friesian spring-calving cows randomly assigned to diets based on perennial ryegrass (GRS), perennial ryegrass/white clover sward (CLV), and total mixed ration (TMR). Raw milks obtained in late lactation were subsequently standardized for fat, heat-treated (90°C for 30 s), evaporated, and homogenized before spray drying. The WMP produced from each diet were analyzed to determine differences in color, particle size distribution, heat coagulation time, yogurt gelation, texture profile, and protein profile due to each diet. Significant differences in heat coagulation time were observed between the CLV and TMR samples, whereas color values were significantly different between GRS and TMR samples. No significant differences in gross composition, protein profile, or whey protein nitrogen index were found between the 3 WMP samples. Average D90 values (the particle size at which 90% of the particles were smaller than the specified size) for fat globules were significantly lower in the TMR sample compared with the GRS and CLV samples. Yogurts produced from GRS- and CLV-derived WMP had significantly higher elastic moduli (G′) than those produced from TMR-derived WMP. Similarly, texture profile analysis revealed significantly higher firmness values in yogurt samples derived from CLV compared with TMR samples. Our data characterize the effect of these diets on the composition and functional properties of fat-standardized WMP, suggesting better yogurt functionality and thermal stability in WMP derived from pasture-based bovine diets.
  • Effects of oligosaccharides on particle structure, pasting and thermal properties of wheat starch granules under different freezing temperatures

    Su, Han; Tu, Jinjin; Zheng, Mingging; Deng, Kaibo; Miao, Song; Zeng, Shaoxiao; Zheng, Baodong; Lu, Xu; National Natural Science Foundation of China; Science and Technology Major Project of Fujian Province of China; et al. (Elsevier, 2020-06-15)
    The effects of fructooligosaccharides (FOS), galactooligosaccharides (GOS), and xylooligosaccharides (XOS) on gelatinization, retrogradation, thermal properties and particle size of wheat starch at different freezing temperatures were studied. The results showed that the wheat starch porosity, particle size, peak viscosity increased with increasing freezing temperature. With the addition of 16% oligosaccharides to starch, the porosity, particle size, crystallinity, initial gelatinization temperature, peak value, breakdown and retrogradation viscosity of the starch granules significantly decreased in the order of XOS > GOS > FOS. However, the pasting temperature of the granules increased. The addition of oligosaccharides (especially XOS, which has the most significant effect in inhibiting starch retrogradation) can inhibit the formation of starch crystal structures to a certain extent, reduce the damage from ice crystals to starch granules and delay starch retrogradation. Therefore, functional oligosaccharides can be used as a potentially effective additive to increase freezing stability in frozen starch-based foods.
  • Processing and Technology of Dairy Products: A Special Issue

    Deeth, Hilton; Kelly, Philip (MDPI AG, 2020-03-03)
    This is the Editorial for a Special Issue " Processing and Technology of Dairy Products"
  • A standardised semi-dynamic in vitro digestion method suitable for food – an international consensus

    Mulet-Cabero, Ana-Isabel; Egger, Lotti; Portmann, Reto; Ménard, Olivia; Marze, Sébastien; Minekus, Mans; Le Feunteun, Steven; Sarkar, Anwesha; Grundy, Myriam M.-L.; Carrière, Frédéric; et al. (Royal Society of Chemistry (RSC), 2020-02-10)
    The link between food and human health is increasingly a topic of interest. One avenue of study has been to assess food disintegration and interactions within the gastrointestinal tract. In vitro digestion models have been widely used to overcome the constrictions associated with in vivo methodology. The COST Action INFOGEST developed an international, harmonised protocol for static simulation of digestion in the upper gastrointestinal tract of adults. This protocol is widely used; however, it is restricted to providing end-point assessment without considering the possible structural changes. On the other hand, there are dynamic models that provide more physiologically relevant data but are expensive and difficult to access. There is a gap between these models. The method outlined in this article provides an intermediate model; it builds upon the harmonised static model and now includes crucial kinetic aspects associated with the gastric phase of digestion, including gradual acidification, fluid and enzyme secretion and emptying. This paper provides guidance and standardised recommendations of a physiologically relevant semi-dynamic in vitro simulation of upper gastrointestinal tract digestion, with particular focus on the gastric phase. Adaptations of this model have already been used to provide kinetic data on nutrient digestion and structural changes during the gastric phase that impact on nutrient absorption. Moreover, it provides a simple tool that can be used in a wide range of laboratories.
  • Water sorption and hydration in spray-dried milk protein powders: Selected physicochemical properties

    Maidannyk, Valentyn; McSweeney, David J.; Hogan, Sean; Miao, Song; Montgomery, Sharon; Auty, Mark A.E.; McCarthy, Noel; Department of Agriculture, Food and the Marine; 15-F-679 (Elsevier, 2020-08-22)
    Low and high protein dairy powders are prone to caking and sticking and can also be highly insoluble; with powder storage conditions an important factor responsible for such issues. The aim of this study focused on the bulk and surface properties of anhydrous and humidified spray-dried milk protein concentrate (MPC) powders (protein content ~40, 50, 60, 70 or 80%, w/w). Water sorption isotherms, polarized light and scanning electron micrographs showed crystallized lactose in low protein powders at high water activities. High protein systems demonstrated increased bulk diffusion coefficients compared to low protein systems. Glass transition temperatures, α-relaxation temperatures and structural strength significantly decreased with water uptake. CLSM measurements showed that humidified systems have slower real time water diffusion compared to anhydrous systems. Overall, the rate of water diffusion was higher for low protein powders but high protein powders absorbed higher levels of water under high humidity conditions.
  • Structural mechanism and kinetics of in vitro gastric digestion are affected by process-induced changes in bovine milk

    Mulet-Cabero, Ana-Isabel; Mackie, Alan R.; Wilde, Peter J.; Fenelon, Mark; Brodkorb, Andre; Irish Dairy Levy Research Trust; Teagasc Walsh Fellowship Programme; BBSRC; MDDT6261; 2014029; et al. (Elsevier, 2018-03-27)
    Bovine milk is commonly exposed to processing, which can alter the structure, biochemical composition, physico-chemical properties and sensory quality. While many of these changes have been studied extensively, little is known about their effect on digestive behaviour. In this study, heat treatments of pasteurisation at 72 °C for 15 s or Ultra-High-Temperature (UHT) treatment at 140 °C for 3 s and homogenisation at pilot-plant scale were applied to whole milk. The gastric behaviour was investigated using a recently developed semi-dynamic adult in vitro model. The emptied digesta were analysed to assess the nutrient delivery kinetics, changes in microstructure and protein digestion. All samples showed protein aggregation and coagulum formation within the first 15 min of gastric digestion at which time the pH ranged from 5.5 to 6. Homogenised samples creamed regardless of heat treatment, whereas all non-homogenised samples exhibited sedimentation. The consistency of the coagulum of the heated samples was more fragmented compared to those of the non-heated samples. Rheological analysis showed that the higher the temperature of the heat treatment, the softer the obtained coagulum and the higher the protein hydrolysis at the end of digestion. The study also confirmed that gastric emptying of caseins from milk is delayed due to coagulation in the stomach, while β-lactoglobulin was emptied throughout the gastric phase, except for UHT-treated milk. The gastric behaviour also had an impact on the lipid and protein content of the emptied chyme. The homogenised samples seemed to release more nutrients at the end of gastric digestion

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