Comparison of batch and continuous ultrasonic emulsification processes

AbstractBatch and continuous ultrasonic emulsification processes on both lab and pilot scales were investigated using Tween 80 or milk protein isolate (MPI) as emulsifiers. The process parameters of processing volume, residence time and ultrasonic amplitude, as well as emulsion formulations, emulsifier type and concentration, were studied for the effect on emulsion droplet size. Emulsions prepared with ultrasound yielded submicron droplets, ∼200nm, with Tween 80 and MPI, utilising all processing methodologies. Inverse power laws were obtained correlating emulsion droplet size with respect to energy density, highlighting the efficiency of the continuous over batch processing. This efficiency is ascribed to the smaller processing volumes, associated with continuous ultrasonic emulsification. Longer processing times were required for MPI to achieve submicron droplets (<200nm) in comparison to Tween 80 as greater times are necessary for interfacial adsorption and surface stabilisation, shown by interfacial tension measurements

The effect of ultrasound treatment on the structural, physical and emulsifying properties of animal and vegetable proteins

AbstractThe ultrasonic effect on the physicochemical and emulsifying properties of three animal proteins, bovine gelatin (BG), fish gelatin (FG) and egg white protein (EWP), and three vegetable proteins, pea protein isolate (PPI), soy protein isolate (SPI) and rice protein isolate (RPI), was investigated. Protein solutions (0.1–10 wt.%) were sonicated at an acoustic intensity of ∼34 W cm−2 for 2 min. The structural and physical properties of the proteins were probed in terms of changes in size, hydrodynamic volume and molecular structure using DLS and SLS, intrinsic viscosity and SDS-PAGE, respectively. The emulsifying performance of ultrasound treated animal and vegetable proteins were compared to their untreated counterparts and Brij 97.Ultrasound treatment reduced the size of all proteins, with the exception of RPI, and no reduction in the primary structure molecular weight profile of proteins was observed in all cases. Emulsions prepared with all untreated proteins yielded submicron droplets at concentrations ≤1 wt.%, whilst at concentrations >5 wt.% emulsions prepared with EWP, SPI and RPI yielded micron sized droplets (>10 μm) due to pressure denaturation of protein from homogenisation. Emulsions produced with sonicated FG, SPI and RPI had the similar droplet sizes as untreated proteins at the same concentrations, whilst sonicated BG, EWP and PPI emulsions at concentrations ≤1 wt.% had a smaller droplet size compared to emulsions prepared with their untreated counterparts. This effect was consistent with the observed reduction in the interfacial tension between these untreated and ultrasound treated proteins

Design and descriptive epidemiology of the Infectious Diseases of East African Livestock (IDEAL) project, a longitudinal calf cohort study in western Kenya

BACKGROUND: There is a widely recognised lack of baseline epidemiological data on the dynamics and impacts of infectious cattle diseases in east Africa. The Infectious Diseases of East African Livestock (IDEAL) project is an epidemiological study of cattle health in western Kenya with the aim of providing baseline epidemiological data, investigating the impact of different infections on key responses such as growth, mortality and morbidity, the additive and/or multiplicative effects of co-infections, and the influence of management and genetic factors. A longitudinal cohort study of newborn calves was conducted in western Kenya between 2007-2009. Calves were randomly selected from all those reported in a 2 stage clustered sampling strategy. Calves were recruited between 3 and 7 days old. A team of veterinarians and animal health assistants carried out 5-weekly, clinical and postmortem visits. Blood and tissue samples were collected in association with all visits and screened using a range of laboratory based diagnostic methods for over 100 different pathogens or infectious exposures. RESULTS: The study followed the 548 calves over the first 51 weeks of life or until death and when they were reported clinically ill. The cohort experienced a high all cause mortality rate of 16% with at least 13% of these due to infectious diseases. Only 307 (6%) of routine visits were classified as clinical episodes, with a further 216 reported by farmers. 54% of calves reached one year without a reported clinical episode. Mortality was mainly to east coast fever, haemonchosis, and heartwater. Over 50 pathogens were detected in this population with exposure to a further 6 viruses and bacteria. CONCLUSION: The IDEAL study has demonstrated that it is possible to mount population based longitudinal animal studies. The results quantify for the first time in an animal population the high diversity of pathogens a population may have to deal with and the levels of co-infections with key pathogens such as Theileria parva. This study highlights the need to develop new systems based approaches to study pathogens in their natural settings to understand the impacts of co-infections on clinical outcomes and to develop new evidence based interventions that are relevant

Effect of enzymatically hydrolysed brewers’ spent grain supplementation on the rheological, textural and sensory properties of muffins

Brewers’ spent grain (BSG) is the major co-product of the brewing industry having a high content of protein and fibre. Enzymatic modification improves the properties of different ingredients when they are incorporated into confectionary products. This study characterised the rheological, textural and sensory properties of unmodified BSG (BSGA) and enzymatically modified BSG (BSGB, i.e., proteinase and carbohydrase modified BSG) when substituted at different levels (5, 10 and 15%) in a muffin ingredient mix. Rheological assessment showed a lower viscosity for the BSGB compared to the BSGA batters. Baked BSGB containing muffins had lower hardness values compared to BSGA and control without added BSG. Sensory assessment showed no significant differences in liking of the different attributes tested (overall appearance, texture, smell, colour and taste) between the 5% BSGA and BSGB supplemented muffins. Incorporation of BSGB at 10% had no negative impact on the sensory attributes in comparison to BSGA 10%. Overall, low level substitution of enzymatic modified BSG beneficially reduced batter viscosity and muffin hardness and gave comparable sensory attributes to those of unmodified BSG supplemented muffins. Therefore, prior enzymatic modification can enhance the ingredient functionality of BSG in confectionary products

Dairy matrix effects: response to consumption of dairy fat differs when eaten within the cheese matrix—a randomized controlled trial

peer-reviewedBackground Dairy fat consumed as cheese has different effects on blood lipids than that consumed as butter. It is unknown whether the effect is specific to fat interaction with other cheese nutrients (calcium, casein proteins), or to the cheese matrix itself. Objective We aimed to test the effect of 6 wk daily consumption of ∼40 g dairy fat, eaten within macronutrient-matched food matrices, on markers of metabolic health, in overweight adults aged ≥50 y. Design The study was a 6-wk randomized parallel intervention; 164 volunteers (75 men) received ∼40 g of dairy fat/d, in 1 of 4 treatments: (A) 120 g full-fat Irish cheddar cheese (FFCC) (n = 46); (B) 120 g reduced-fat Irish cheddar cheese + butter (21 g) (RFC + B) (n = 45); (C) butter (49 g), calcium caseinate powder (30 g), and Ca supplement (CaCO3) (500 mg) (BCC) (n = 42); or (D) 120 g FFCC, for 6 wk (as per A) (n = 31). Group D first completed a 6-wk “run-in” period, where they excluded all dietary cheese before commencing the intervention. Results There was no difference in anthropometry, fasting glucose, or insulin between the groups at pre- or postintervention. However, a stepwise-matrix effect was observed between the groups for total cholesterol (TC) (P = 0.033) and LDL cholesterol (P = 0.026), with significantly lower postintervention TC (mean ± SD) (5.23 ± 0.88 mmol/L) and LDL cholesterol (2.97 ± 0.67 mmol/L) when all of the fat was contained within the cheese matrix (Group A), compared with Group C when it was not (TC: 5.57 ± 0.86 mmol/L; LDL cholesterol: 3.43 ± 0.78 mmol/L). Conclusion Dairy fat, eaten in the form of cheese, appears to differently affect blood lipids compared with the same constituents eaten in different matrices, with significantly lower total cholesterol observed when all nutrients are consumed within a cheese matrix This trial was registered at ISRCTN as ISRCTN86731958.Enterprise Irelan