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Item Candidate gene search for milk production and composition, milk coagulation properties, and milk protein profile in dairy sheep from a New Zealand flock(Taylor and Francis Group, 2025-07-11) Marshall AC; Lopez-Villalobos N; Vigolo V; Marchi MD; Loveday SM; Weeks M; McNabb WThe objective of this study was to perform genome-wide association analysis and thus search for candidate genes for milk production and composition, milk coagulation properties (MCP), and milk protein profile in dairy sheep from a New Zealand flock. After quality control, 45,801 single nucleotide polymorphisms (SNPs) were included in the analysis, 147 ewes, and 470 individual records. A total of 87 SNPs and 55 candidate genes were found across Ovis aries autosomes (OAR) 2, 3, 6, 16, 18, 20, 25, and 26. Of particular importance, were the candidate genes PDZRN4 for milk yield, and BMP2K for contents of αs1- and αs2-caseins. No SNPs were found in the casein genes, LALBA or PAEP. Only one SNP was significant for MCP, and overall, the genetic architecture of MCP was similar to that of ratio of casein to calcium, pH, lactose, and the ratio of casein to protein. Further studies with larger flocks and with genomic imputation are required to validate the findings of this study before incorporating markers or genes into breeding programmes.Item Effect of protein polymorphisms on milk composition, coagulation properties, and protein profile in dairy sheep(Elsevier Ltd, 2025-01-01) Marshall AC; Vigolo V; De Marchi M; Lopez-Villalobos N; Loveday SM; Weeks M; McNabb WThe objective of this study was to quantify the effect of protein polymorphisms on milk composition, coagulation properties, and protein profile in dairy sheep from a New Zealand flock. A total of 470 test-day records, from 147 lactating ewes, were used in the statistical analyses. Protein polymorphisms observed in the RP-HPLC were self-named for purposes of the present study. Data were analyzed using a mixed linear model, including the fixed effects of ewe age, litter size, coat-colour, and stage of lactation, and, as a covariate, deviation from the median lambing date of the flock. The effects of protein polymorphisms were added to the model, one at a time. Protein polymorphisms were significantly (p < 0.05) associated with milk composition and protein profile. Polymorphisms of β-lactoglobulin were significantly associated with milk heat stability, being AB type more heat stable than AA. The other processability traits were not significantly affected by protein polymorphisms. Further studies are required to confirm the protein variants and the properties of individual protein polymorphisms.Item Genome-wide association studies for citric and lactic acids in dairy sheep milk in a New Zealand flock(Taylor and Francis Group, 2024-08-05) Zongqi A; Marshall AC; Jayawardana JMDR; Weeks M; Loveday SM; McNabb W; Lopez-Villalobos NThe objectives of this study were to estimate genetic parameters for citric acid content (CA) and lactic acid content (LA) in sheep milk and to identify the associated candidate genes in a New Zealand dairy sheep flock. Records from 165 ewes were used. Heritability estimates based on pedigree records for CA and LA were 0.65 and 0.33, respectively. The genetic and phenotypic correlations between CA and LA were strong-moderate and negative. Estimates of genomic heritability for CA and LA were also high (0.85, 0.51) and the genomic correlation between CA and LA was strongly negative (-0.96 ± 0.11). No significant associations were found at the Bonferroni level. However, one intragenic SNP in C1QTNF1 (chromosome 11) was associated with CA, at the chromosomal significance threshold. Another SNP associated with CA was intergenic (chromosome 15). For LA, the most notable SNP was intragenic in CYTH1 (chromosome 11), the other two SNPs were intragenic in MGAT5B and TIMP2 (chromosome 11), and four SNPs were intergenic (chromosomes 1 and 24). The functions of candidate genes indicate that CA and LA could potentially be used as biomarkers for energy balance and clinical mastitis. Further research is recommended to validate the present results.Item Spoilage bacteria in ewe milk and the sheep dairy farm environment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science/Microbiology at Massey University, Manawatū, New Zealand(Massey University, 2023-03) Risson, AlexisMilk spoilage bacteria are capable of impacting the stability, processability, and overall quality of dairy products. These contaminants are highly diverse and can be found at various stages of the dairy production, but the majority originate from the dairy farm environment where they contaminate raw milk. On bovine dairy farms, research has identified several routes of transmission of spoilage microorganisms into raw milk, as well as some of the factors that modulate this process. This knowledge has aided the design, development and implementation of interventions aiming to limit the on-farm contamination of raw milk and thereby improve the microbiological quality of cow dairy products. In contrast, the microbial communities associated with the ovine dairy production have been largely overlooked. This lack of understanding of the ecology and transmission of spoilage bacteria on sheep dairy farms and in dairy products hinders attempts at reducing the farm-borne contamination of ewe milk by spoilage organisms. In this thesis, I set out to identify and characterise the microbial communities associated with the ovine dairy production, with a focus on bacteria capable of impacting ewe milk quality. In the first part, I compiled, developed, and subsequently used an extensive set of culture methods targeting the main types of bacteria implicated in dairy spoilage, namely spore-forming bacteria, and Pseudomonas species. These methods were applied to survey the microbial communities present in the farm environment of dairy ewes that were grazed or housed. For the first time, this approach provides a detailed overview of the ecology of spoilage bacteria found on sheep dairy farms and enables the identification of numerous bacterial species with spoilage potential. The diversity and principal reservoirs of spoilage bacteria were found to vary between the two farms, possibly as a result of their farming practices. In the second part, I performed source-tracking of the contaminants isolated from milking cups using phylogenetic tools such as DNA fingerprinting and whole-genome sequencing. According to this approach, sources of milking cup, and thus possibly raw milk contamination were found to vary between the two farms. In the barn environment, the silage-faeces axis was identified as the main source of spoilage bacteria in the wider farm environment and in milking cups. There was also some contribution, albeit minimal, from bedding materials and animal drinking water as potential intermediaries. In the pasture environment, the transmission of bacteria in the environment was low, but the origin of the contaminants found in milking cups was multiple, dependent on the bacteria considered, and included soil, pasture, animal faeces and drinking water. In addition, the phylogeny of Thermoactinomyces spp., which were found to be particularly abundant in both housing and grazing environments, was studied in more depth using whole-genome sequencing. Finally, I surveyed the microbiological quality of ewe raw milk samples and sheep dairy products produced in New Zealand using the culture methodology developed for the farm studies. This work provided a glimpse of the diversity and abundance of the spoilage microbiota of sheep milk and dairy products produced in New Zealand. It was found that the microbiological quality of sheep dairy products was high, however, the presence of a highly diverse range of spoilage bacteria highlights their potential to impact the quality of a variety of dairy products.Item Studies on heat-induced protein interaction and digestion behavior of sheep milk : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Riddet Institute, Massey University, Palmerston North, New Zealand(Massey University, 2023) Pan, ZhengSheep milk has low heat stability, which results in undesirable changes after heat treatment, such as separation of milk fat, sediment formation, and phase separation. However, the mechanism of low heat stability of sheep milk has not yet been elucidated. Additionally, the protein interactions in sheep milk during heating and the digestion behaviors of differently processed sheep milk are also unknown. Therefore, the aim of this thesis was to explore the protein interactions of sheep milk during heat treatment (67.5–90 °C and 140 °C), and the mechanism of heat coagulation of sheep milk. In addition, the effect of the commercial processing treatment [homogenization (200/50 bar) and thermal (75 °C/15 s and 95 °C/5 min) processing] on the digestion behavior of sheep milk were determined. Sheep skim milk (SSM) was heated under various conditions (including temperatures, heating times and pH values) and the denaturation of whey protein and protein interactions occurring during heating were characterized using high-performance liquid chromatography. Casein micelle diameter increased upon heating, depending on the temperature and time. The association of whey protein with casein micelles and the aggregation of casein micelles occurred simultaneously and contributed to the increase in casein micelle size in SSM. SSM was stable to heat (140 °C) at pH 6.8–6.9 but became unstable at higher or lower pH. The low heat stability of sheep milk was attributed to the low proportion of κ-casein surrounding the casein micelles, high ionic calcium levels and ready dissociation of κ-casein from casein micelles upon heating at pH 7.0. The Human Gastric Simulator was used for in vitro dynamic gastric digestion and pH-stat for simulated small intestinal digestion. Heat treatment of sheep milk resulted in the incorporation of MFGs into the curds through casein‒whey protein or whey protein‒whey protein interactions; this hindered the formation of the closely knitted protein network and led to the formation of fragmented curds. Homogenization of sheep milk resulted in looser and more fragmented curd in comparison with unhomogenized sheep milk; this accelerated the protein hydrolysis and increased the rate of release of protein, fat, and calcium from the curds into the digesta. Processing treatments affected the lipolysis rate but not the lipolysis degree during small intestinal digestion. In conclusion, the findings of this study have advanced our understanding of the heat-induced protein interactions in sheep milk and provided insights into the digestion behavior of differently processed sheep milk within the gastrointestinal tract. This may help to design and develop sheep milk-based products with desired digestive and functional properties.Item Development of a rapid liquid freezer : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatū, New Zealand(Massey University, 2021) Morel, JolinSmall sheep dairy farms often make insufficient volumes of milk for economic daily collection and are limited by transport distances to processors. A method of long-term on-farm storage of milk would enable the industry to grow. Freezing would allow extended milk storage on farms. But existing methods of freezing for on-farm applications have shortcomings around materials handling, labour requirements and product quality. The project reported in this thesis aimed to develop the engineering science behind an economically viable freezing method that would improve on current methods. The first period of this project focused on two freezer designs which were thought to be promising: Rolling Droplet Freezing (RDF) and Falling-Film Flake freezing (FFF). RDF was selected as the initial focus of the research program and consisted of a system where droplets of milk would roll down an angled super-hydrophobic surface against a cold air flow and freeze. RDF was abandoned due to concerns about construction costs and operating reliability. In a condensing atmosphere, droplets rolling on superhydrophobic surfaces occasionally transitioned from a Cassie-Baxter wetting state to a Wenzel wetting state, which caused the droplets to stick. FFF was then developed further. A pilot scale unit was designed and constructed, and preliminary pilot-scale trials that were conducted with pure water and ovine milk reconstituted from powder. The partition coefficient of FFF was measured as 0.946 at an operating temperature of -30°C. At higher operating temperatures the partition coefficient was reduced. Detaching frozen solids by applying a burst of heat to the freezer/ice interface was studied and this method of detachment was successful with pure water, but ineffective for ovine milk. The development of FFF was put on hold with the conception and development of the continuous tubular freezer. Ice formed in a solution can show morphologies ranging from highly dendritic structures with entrapped solutes, which are homogenous on a gross scale, to large crystals of pure ice with solutes rejected and compressed into inter-crystalline spaces. To investigate which sheep milk components influence ice morphology at various freezing rates, whole milk was separated into skim milk and into a casein-free serum phase. A simulated sheep milk ultrafiltrate was also prepared. The morphology of the ice/sample interface was observed in a custom-built microscope stage at freezing front velocities from <0.5 μms⁻¹ to 50 µms⁻¹ with a spatial temperature gradient of 35-38 Kcm⁻¹. The morphology arising from extremely rapid freezing front velocities was investigated by supercooling slides on a temperature-controlled stage and observing the nucleation and recalescence of the samples. The morphology of ice at the interface changed from a planar to columnar and then to dendritic as freezing front velocity increased, with the transitions from one morphology to another occurring at lower speeds in more complicated solutions. A map of freezing front behaviours was developed. The transition between interface morphologies was at different velocities and transition differed based upon the interface velocity. At lower interface velocities a columnar interface grew directly from a planar starting condition. At higher velocities an intermediate dendritic zone formed, which then settled into a columnar interface. The ice formed by rapid freezing from subcooled solutions was highly dendritic, with ice growth rates of approximately 21,000 μms⁻¹, which was close to the diffusion-limited ice growth rate in water of similar degrees of supercooling. The morphology of frozen ovine milk was also studied by Cryogenic Scanning Electron Microscopy (Cryo-SEM): Milk was frozen by three different methods-slow quiescent freezing (SF), rapid directional freezing (DF), and droplet freezing in LN₂. Ice crystals rejected unfrozen solids into the region between crystals in all samples, including those frozen by immersion into liquid nitrogen. There was a distinct difference in morphology between the SF and DF samples, with the bands of unfrozen solids being significantly smaller in DF samples, and the long axes of ice crystals were aligned with the direction of heat flow. SF samples lacked any particular ice growth direction, and ice crystals were orders of magnitude larger. Lactose crystallisation was observed in some SF samples but was not observed in any DF samples. Fat globules were engulfed in ice crystals in DF samples, but rejected in SF samples. To study the effects of frozen storage temperature and time, samples of raw ovine milk were stored frozen at -10°C, -18°C and -28°C to -30°C for up to 8 weeks. Further samples were stored below -20°C for 6 months. After thawing at 20°C, samples were tested for a range of properties and serum samples were collected by separating the fat phase and micellar casein phase by centrifugation. A gel was observed in milk stored at -10°C for 4 weeks and 8 weeks but was not observed in milk stored at lower temperatures. The gel dispersed under heating and homogenisation. There was no change observed in the pH, or serum protein level of thawed samples after frozen storage at any temperature. The whiteness of the milk decreased during frozen storage and the yellowness increased. Both of these changes were reversed on homogenisation. The serum Ca²⁺ levels in milk stored at -10°C and -18°C dropped over the storage period, while no trend was seen in milk stored below -28°C, indicating that the migration of Ca²⁺ may play a role in the formation of gels after frozen storage. Milk that had been stored below -20°C for 6 months had a similar viscosity and appearance to fresh milk. A possible mechanism for the formation of gels at -10°C, but not -18°C or -28°C lies in the altered solute environment, and the physical agglomeration of milk components in the spaces between ice crystals, driving the gelation of closely packed casein micelles, with Ca²⁺ stabilising this network. It is well established in literature that the viscosity of an unfrozen phase increases by several orders of magnitudes as it decreases in temperature and approaches a glassy state. This increased viscosity reduces protein mobility and solute diffusion, which reduces the rate of gel formation. The tendency for frozen milk particles to bind together during frozen storage was evaluated. Frozen pellets of whole ovine milk were stored under weights at -10°C and -18°C and pellets of frozen concentrated milk stored at -18°C and -28°C. Ovine milk pellets bound together at -10°C but not -18°C, while concentrated milk bound together at -18°C, but not -28°C. This can be linked to the volume and viscosity of the unfrozen phase in these samples. Differential scanning calorimetry was used to determine the fraction of freezable water frozen at any temperature. The melting onset temperature was observed, and this was used to determine the solids content maximally freeze concentrated solution (𝑋𝑠(𝑇𝑚)). 𝑋𝑠(𝑇𝑚)=0.875 for whole ovine milk 𝑋𝑠(𝑇𝑚)=0.85 for skim milk, and 𝑋𝑠(𝑇𝑚)=0.81 for ovine milk serum. This was also determined for whole ovine milk by the magnitude of the overall latent heat release during melting, which gave a value for whole milk of 𝑋𝑠(𝑇𝑚)=0.85±0.016. A partial phase diagram for ovine milk was generated from the data collected. The insights generated from observing both the dendritic morphology of high velocity ice fronts and progressive freezing behaviour led to conceptualising a novel tubular freezer, subsequently constructed. It was hypothesised that reducing the volume or area of ice in contact with the freezer wall, due to the inclusion of unfrozen product, could reduce the adhesion strength between a frozen product and the freezer wall. By controlling the outlet temperature, the volume fraction of unfrozen product could be controlled. The adhesion strength could thereby be controlled, and a set of operating conditions could be found that would allow a mostly frozen product to be extruded as a solid from a cooled tube by a high-pressure pump. This was tested on a benchtop scale (up to 5mL/minute, with a freezer internal diameter of 4.2mm and cooled length of 500mm), with ovine milk, fruit juice, fruit pulp, concentrated coffee, bovine cream and concentrated milks. The system successfully froze all samples. The operating pressure was found to increase with increased frozen fraction, and therefore with decreased operating temperature. The ice morphology of milk and juice frozen by this equipment was imaged by cryo-SEM and by optical microscopy. The ice crystals were radially aligned, increasing in size closer to the centre of the frozen product plug, which was expected due to the heat flows and the relationship between freezing front velocity and feature sizing. This positive preliminary result led to the construction of a larger scale prototype unit which consisted of a spiral tube with a length of 5000 mm, and an internal diameter of 10 mm. This was used successfully for a product flowrate of approximately 6 kghr⁻¹.Item A study of the Romney fat lamb ewe, with particular reference to milk secretion and its effect on fat lamb production : thesis submitted by "392" [Alan Graham Logan] for the M. Agr. Sc. degree at Massey University(Massey University, 1946) Logan, Alan GrahamOne of the distinguishing characteristics of mammals, is the dependance of the young, during early post-natal life, on nourishment secreted by the mammary gland of the mother. Hence milk secretion is of fundamental importance in all our farm animals with the exception of poultry. The essential attributes of milk (viz., high water content and liquid state, high digestibility, high protein content of excellent biological value, high calcium and phosphorus and the presence of most of the necessary vitamins) are specially suited to the needs of young rapidly growing animals. In dairy cattle extensive study has been made of milk producing ability and conscious effort made to improve this by breeding, and nutrition. Comparison of the characteristics of modern dairy cattle (highly developed milking qualities but inferior meat carcasses) and of beef cattle (early-maturing and good carcass quality but often poor milk yield) clearly indicate the extent of improvement from the wild form and the variation in productive efficiency of different types. Valuable work on the milk-producing ability of other species, and its relationship to the welfare of the young has been carried out by Bonsma and Oosthuizen (1) and Donald (7) with Sows; and Ritzman (30), Fuller and Kleinhanz (10), Neidig and Iddings (24), Bonsma (2,3), 30a, Pierce (27,28) with ewes of non-milking breeds, and by several workers with specialised milking sheep, Scheingraber (31), Muhlberg (23), Maule (17). [From Introduction]Item Discovering food product design by shaping sheep's cheese perception in New Zealand : an exegesis presented in partial fulfilment of the requirements for the degree of Masters of Design at Massey University, Wellington, New Zealand(Massey University, 2018) Fallas, PilarThe Food Industry is more interested than ever in creating value through differentiation and innovation, but often overlooks creativity as key factor in generating returns from food product experiences. This project is an exploration into how design; as a creative discipline, and food science, as a technical discipline, can more closely align and collaborate to create valuable food product experiences. To explore this nexus, I exposed myself, a food scientist, to the creative research practices of design in order to develop a new cheese product. The project is a contribution to the development of New Zealand's fledgling sheep dairy industry. I first examined New Zealanders' traditional perceptions and hidden desires in relation to sheep milk products. I then explored the different dimensions of the food object (Bassi, 2015) by developing a range of sheep's cheese products to help New Zealanders become more adventurous sheep milk product consumers.Item Development of a sheep's milk kefir using species isolated from kefir products : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2017) Brown, Madeleine Frances WebsterThe aim of the research described in this thesis was to develop a good tasting kefir using sheep’s milk. Kefir is a refreshing and effervescent milk beverage fermented with bacteria and yeast. Different combinations of bacteria, yeast and treatment result in different qualities of Kefir. An optimal kefir has a pleasant slightly sour flavour and is slightly effervescent. It is drunk chilled. To arrive at preferred or optimal kefir the following steps occurred: Yeast and bacteria were isolated using MRS, M17, and DRGB agar from five commercial and three homemade kefir products. 54 isolates were identified using 16s rDNA PCR for bacteria, and 26s rDNA for yeast. The commercial yeasts were: Saccharomyces cerevisiae, and Torulaspora delbrueckii, the commercial bacteria were: Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides, Lactobacillus plantarum, Lactococcus lactis subsp. cremoris, and Leuconostoc pseudomesenteroides, and Leuconostoc pseudomesenteroides. The homemade yeast were: Kluyveromyces marxianus, Kazachstania unispora, Pichia membranifaciens, and Clavispora lusitaniae, and the homemade bacteria were: Lactobacillus delbrueckii, Lactobacillus kefiranofaciens, and Lactobacillus kefiri. Streptococcus thermophiles was the only isolate found in both homemade and commercial kefir. One isolate of each species identified was used to form a starter culture and grown in gamma sterilized sheep’s milk, allowing the assessment of the growth characteristics required for kefir. The characteristics assessed were; cell counts, pH, textural properties, effervescence, and the levels of lactose, glucose, galactose, ethanol, lactic acid, acetic acid, and diacetyl using HPLC. The results from these tests were used to determine the optimum mix of species for a sheep’s milk kefir. Four different mixes of 5-6 isolates were chosen based on the results of the individual isolates and grown in sheep’s milk and tested for the same characteristics as the pure isolates as well as taste tested. This optimised kefir was made by inoculating 1x106cuf/mL of each isolate to sheep’s milk, sealed in the final container and fermented at 30°C for 24 hours. After cooling to 4°C the final product has a refreshing sour taste and effervescence, with a pH of 4.6, and a cell count above 3x109cfu/mL which decreases to above 9x108cfu/mL after five weeks, which is over 106cfu/mL required for labelling purposes.Item Process development for a sheep whey beverage : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2017) Weerawarna N R P, Maheeka IsurinieThe potential of New Zealand sheep whey as a stable base ingredient in beverage manufacturing was studied using 4 model whey and 7 commercial whey streams. In order for sheep whey containing beverages to have a commercially adequate shelf life they are required to undergo a heat treatment. Due to the artisan small scale nature of sheep cheese manufacture in New Zealand heat treatment using continuous processing was not deemed feasible. The most likely form of heat treatment would be in package batch heating to 90°C with the pH of the beverage less than pH 4.6. Thus this study investigated the variations in the physicochemical composition of sheep whey as a function of cheese manufacturing on heat treatment (90°C/ 5min) under varying acidic pH conditions (pH 4.5 and pH 3.5). The composition of sheep whey varied primarily based on the pH of the cheese curd formation and separation method. Additionally, the whey composition also differed with the type of cheese produced and quality control of the process by each manufacturer. Of particular importance is the curd separation technique as this can result in casein contamination of the whey. A model study containing 5% w/v of contaminating curd in whey showed that significant Ca and Mg migrated from the curd into the whey during overnight cold storage (5°C) at pH 3.5 resulting in an overall increase in ionic strength of the whey. The stability of sheep whey during heat treatment (90°C for 5 min) at pH 4.5 and pH 3.5 was studied via sedimentation and colour (L, a, b) measurement. The L value of whey samples heated at pH 4.5 increased and the samples produced 13 – 40% (v/v) sedimentation after overnight storage at 5°C. Comparatively, whey heated at pH 3.5 was generally stable with less than 1% (v/v) sedimentation and no significant changes in the L value. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed comparatively high loss of monomeric whey proteins in whey heated at pH 4.5 than at pH 3.5 and further confirmed the above results. However, a commercial whey with high ionic strength (conductivity 193.6 mS cm-1) was unstable at pH 3.5 heat treatment and produced about 40% (v/v) sedimentation and a prominent increase in the L value. Consequently, an extended study on the effect of ionic strength, varied by the addition of NaCl, on heat stability (90°C for 5 min at pH 3.5) of sheep whey was performed. Whey was stable with up to 0.1 mol L-1 added NaCl (conductivity 102.1 mS cm-1) and produced 6% (v/v) sedimentation after the heat treatment followed by the overnight storage. In contrast, a dramatic increase in sedimentation (about 60%, v/v) was evident at 0.15 mol L-1 NaCl with gradual reduction of sedimentation upon subsequent addition of NaCl. Transmission electron microscopy (TEM) images of the sediments showed hairy like aggregates at 0.15 mol L-1 NaCl which became dense with further increases in NaCl concentration and perhaps explain the sedimentation behaviour. Further, conductivity of whey increased linearly with increasing NaCl concentration (R2 = 0.98 at a 95% level of confidence) and thus conductivity measurement could be used to predict the stability of whey during thermal processing. Moreover, a prototype whey beverage was produced using the above established conditions (90°C for 5 min heat treatment at pH 3.5 and conductivity below 102.1 mS cm-1). However, the product, which was heated in 450 mL bottles (at 1.94°C/ min) rather than the test tubes (at 28°C/ min) of the earlier work, were found to be unstable. Further a rapid heat treatment (at 4.7°C/ min) of the beverage only produced floating aggregates. It was thought that the instability was due to extended heating and cooling rates. A subsequent study showed that holding time at the heat treatment affected the properties of whey protein aggregates and consequently produced either floating aggregates or sediments. Therefore, minimizing heating and cooling rates would be a significant consideration in commercial scale sheep whey processing. Additionally, the research outcomes would assist on-site decision making for individual cheese manufacturers on the utilisation of different sheep whey streams as a stable base ingredient in beverage processing.