Massey Documents by Type
Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294
Browse
12 results
Search Results
Item Emulsion-based delivery systems to improve gut and brain bioaccessibility of curcumin in relation to Alzheimer’s disease prevention : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand(Massey University, 2023) Lunelli, TacianaMedium chain triglycerides (MCT) from coconut oil, omega-3 polyunsaturated fatty acids from fish, phospholipids from dairy milk, and curcumin from turmeric all have been recognized for their anti-inflammatory and antioxidant properties. Curcumin is also a potential candidate for Alzheimer’s disease (AD) prevention; however, curcumin is poorly bioavailable unless emulsified. The milk fat globule membrane (MFGM) has natural emulsifying properties. I aimed to design an emulsion-based delivery system containing functional oils to encapsulate and deliver curcumin to the brain. I evaluated three commercial MFGM components with coconut and fish oils to produce emulsions with improved curcumin bioavailability. The emulsion structures were characterised by particle size, zeta-potential at the surface, microscopic structure, curcumin loading efficiency, and phospholipid distribution. All emulsions showed stable to particle size changes over 40 days at 4°C. Emulsion particle size decreased significantly with increasing concentrations of emulsifier, and presented negative zeta-potential varying from -50 to -20 mV, with the MFGM fractions creating significantly different charges and curcumin loading efficiency based on phospholipid and protein composition. All MFGM fractions efficiently created stable emulsions with small particle size and encapsulated curcumin. After simulated in vitro digestion, the emulsion with the highest phospholipid content had significantly higher curcumin bioaccessibility compared to the others. Fresh and digested emulsions and their components were assessed in the BE(2)-M17 neuroblastoma cell model for amyloid-β (Aβ) toxicity. Emulsions composed of both fish and coconut oils provided greater protection against Aβ toxicity compared to coconut oil alone. Curcumin was transported in vivo across the intestinal wall to the bloodstream and across the blood-brain barrier to the brain in rats fed all curcumin delivery formats. The kinetics of curcumin in blood and brain varied depending on the emulsion format. MFGM emulsions significantly reduced the curcumin and its metabolites peak time in blood and brain compared to the commercial curcumin preparation Meriva®, and all emulsions improved overall curcumin bioavailability and accumulation in the brain compared to free curcumin. A novel ex vivo approach using rat plasma samples directly in the neuroblastoma cell model requires further optimisation but demonstrated a significant interaction between gender and treatment on cell viability.Item The gross composition, fatty acid composition, and processability of milk from cows milked once and twice a day under New Zealand grazing conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science, Massey University, Palmerston North, New Zealand(Massey University, 2023) Sanjayaranj, InthujaaIn New Zealand, milking once a day (OAD) is practised by some farmers, with the majority of farmers milking twice a day (TAD). Once-a-day milking provides several benefits such as reduced labour cost, improved labour efficiency, improved health and reproductive performance of cows, and additional employment opportunities for farmers. Once-a-day milking causes a reduction in milk yield and modifies milk composition by increasing the fat and protein percentages. The main aim of this thesis was to study the effect of OAD milking on the gross composition, fatty acids composition, and processability of milk. To achieve this, the milk from 232 cows from a OAD herd and 182 cows from a TAD herd were collected in a full season in early, mid-, and late lactation. The samples were analysed for milk composition and fatty acid composition using Fourier-transform mid-infrared (FT-MIR) spectroscopy. Calibration equations for individual and grouped fatty acids were developed using FT-MIR calibrator software. Milk coagulation properties (rennet coagulation time, curd firming rate, and curd firmness) were analysed using a Formagraph. In addition, a SNP (rs109421300) in the diacylglycerol acyltransferase 1 (DGAT1) region on bovine chromosome 14, which is associated with a higher fat percentage in milk, was selected to study its association with fatty acid composition. Solid fat content at 10°C (SFC₁₀), a parameter that predicts butter hardness, was calculated using an equation developed from the proportions of fatty acids. The proportions of de novo synthesised fatty acids (C8:0-C14:0) were significantly higher, and the proportions of preformed, long-chain fatty acids (mainly C16:0 and C18:0) were lower in milk from cows milked OAD compared with cows milked TAD. Milk coagulation properties were superior for Jersey cows compared with Holstein-Friesian and Holstein-Friesian × Jersey cows milked OAD and TAD. The CC genotype of SNP rs109421300 was associated with higher fat yield, fat percentage, protein percentage, and SFC₁₀. Milk from OAD cows had lower proportions of C16:0 suggesting it would produce more easily spreadable butter. Selecting cows with the CC genotype would be suitable for the New Zealand dairy industry with the current payment system, however, the CC genotype was less suitable for making more easily spreadable butter. Overall, there were some significant differences noted between milk from cows milked OAD and TAD in terms of fatty acid composition and processability.Item The release of lipids from dairy food matrices under in vitro gastrointestinal digestive conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatū, Palmerston North, New Zealand(Massey University, 2022) Tai, PatrickThe milk fat globule membrane (MFGM) is a trilayer phospholipid and protein interface that separates the triacylglycerides from the serum phase. Consumption of MFGM phospholipids decreases serum cholesterol in adults with high risk for hypercholesterolemia and modulates serum cholesterol in healthy adults. The biochemical mechanism behind this putative effect is currently unknown. The large majority (~80%) of the cholesterol in the milk fat globule is localized in the MFGM in complexation with sphingomyelin to form liquid-ordered (Lo) domains. The nutritional and digestive implications of consuming Lo domains have been scarcely considered. Considering sphingomyelin strongly complexes with cholesterol, the MFGM is rich in sphingomyelin, and the consumption of MFGM material has shown to modulate serum cholesterol, there is a likely link between the presence of Lo domains and the nutritional benefit of consuming MFGM material. Model bilayer systems, phospholipid liposomes/vesicles, were created from phospholipids derived from natural sources: soy phosphatidylcholine (SPC), porcine brain phosphatidylcholine (BPC), egg sphingomyelin (ESM), milk sphingomyelin (MSM), milk fat globule membrane (MFGM) phospholipids extracted from bovine beta-serum, and ovine cholesterol. The structural and thermotropic properties of the vesicles were investigated under in vitro gastrointestinal conditions. First, a screening test was performed on MSM/cholesterol multilamellar vesicles (MLVs). Instruments were capable of detecting shifts in the vesicles from solid-ordered (So) and liquid-disordered (Ld) to liquid-ordered at 2 × the MSM concentration found in raw milk. Incubation with physiologically relevant concentrations of bovine bile demonstrated 3:2 mol/mol MSM/cholesterol MLVs were capable of resisting detergent-induced solubilization by bile salts. The SPC/cholesterol, BPC/cholesterol, and MFGM/cholesterol phospholipid vesicles were disrupted. At the endpoint of in vitro gastrointestinal digestion, 3:2 mol/mol MSM/cholesterol MLVs also experienced micellization – however there was no statistically significant difference in the total bilayer order of the vesicles, implying a degree of structure possibly remained. Further investigation on the detergent solubilization of MFGM phospholipid vesicles by bile salts revealed that although the vesicle was disrupted, the mixed micellar size growth was minimal. That is, there was a lack of phospholipid exchange between vesicle and micelle. These findings set the stage for further research into the bioactive potential of milk phospholipids.Item Studying the relationship between emulsion structure and lipid digestibility for infant milk : a thesis was present in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology, at Massey University, Palmerston North, New Zealand(Massey University, 2020) Deng, LeMilk, whether maternal or formulated, provides the sole source of nutrition to infants in the early stages of life, providing critical micronutrients, support for the immune function and primary dietary macronutrients including lipids. In healthy adults, lipids are primarily digested in the small intestine. However, for infants, the neonatal small intestine is not fully developed after birth, so the gastric environment plays a more significant role in milk fat digestion. Clinical studies have shown that maternal milk fat is digested more efficiently than lipids in infant formulae in infants under infant gastric conditions. Compositional differences, the structure of the oil droplets, and especially the interfacial composition may all play a crucial role in influencing lipid digestibility in the infant's stomach. In this thesis, the simulated gastric digestion of model emulsions and commercial infant formula was studied. The model emulsions comprised either a phospholipid or complexed protein-phospholipid interface while keeping all other facets of emulsion properties equivalent. Gastric digestion of these emulsions was carried out across variable pH conditions using an analogue gastric lipase, alone and in combination with pepsin with findings providing insights into the role of each enzyme and their combined effect on gastric lipolysis. The rate and extent of lipolysis were characterised, along with morphological changes to the structure of the oil droplets. Results showed that gastric lipolysis might be influenced by pH conditions in the gastric environment when lipase was present alone in the simulated gastric fluid. The inclusion of pepsin resulted in significant structural changes when emulsions were stabilised with protein, in terms of droplet aggregation, size and morphology. However, no significant differences in the extent of lipolysis were determined. Thus, while the protein interface of both model and formulated emulsions was not observed to be a barrier for gastric lipolysis. Proteolysis of protein stabilised emulsions may lead to very different structural outcomes during gastric digestion when compared to phospholipid stabilised emulsions. While the research within this thesis demonstrates how the gastric environment influences emulsion structure as a consequence of interfacial composition, any specific relationship between structure and relative rate of gastric lipolysis currently remains undetermined. This research also highlights some of the ongoing challenges in the use of in vitro models to provide mechanistic understanding and interpretation of findings from clinical studies.Item The GLC analysis of three component fat/oil mixtures in the determination of component proportions : a thesis presented in partial fulfilment of the requirements for Master in Technology degree at Massey University(Massey University, 1983) Wong, Yuk ChuBy making use of the fatty acid composition of mixture and the three-fat(s)/oil(s) mixture, obtained from the gas-liquid chromatographic analysis, the relationship between mixture components and mixture was expressed by the general mixture equation: (Ai - Ci) X1 +(Bi-Ci) X2 = (Mi - Ci) where Ai is the fatty acid percent value of the first mixture component; Bi is the fatty acid percent value of the second mixture component; Ci is the fatty acid percent value of the third mixture component; Mi is the fatty acid percent value of the mixture; X1 is the fraction of the first component in the mixture; and X2 is the fraction of the second component in the mixture. The fraction of first two mixture component can then be estimated by solving simultaneous mixture equations. This can be done either by employing the Cramer's Rule method (McCracken and Dorn, 1964) or by the Gauss-Jordan Elimination method (Dodges, 1978). The third mixture component proportion (i.e. X3) can be obtained by substituting X1 and X2 into the following equation: X3 = 1 - X1 - X2 The F77 FREQC program, using the Gauss-Jordan Elimination Method to estimate the proportion of each mixture component and the Frequency Method to calculate the weighted mean proportion of each mixture component, gave the best results with almost all of the calculated weighted mean mixture component proportions to be within two calculated standard deviations. The accuracy of the calculated estimations was dependent upon the accuracy of the experimental and literature component data. In most cases, literature data did not produce as good results as those calculated from experimental data.Item Regulation of mammary stearoyl-CoA desaturase and the effects on milk fat composition in lactating mice : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Human Nutrition at Massey University, Palmerston North, New Zealand(Massey University, 2000) Hartley, Darren GuyThe research described in this thesis tested, in the lactating mammary gland of female Swiss mice, a model for the control of lipogenesis developed for the liver of male mice. In male mice feeding a fat free diet, or a diet containing 0.5% w/w clofibrate, induces hepatic stearoyl CoA desaturase (SCD) mRNA transcription, which increases SCD activity and the amount of oleate incorporated into membrane phospholipids and the triacylglycerols of liver lipoprotein. In a preliminary trial, SCD mRNA in liver and mammary gland and fatty acids (FA) in the liver, mammary gland and milk fat were measured in three groups (n=3) of lactating mice fed either a control diet or the control diet with added clofibrate (0.05% w/w) or a fat free diet. Concentrations of SCD mRNA in liver and mammary gland and proportions of individual FA in liver, mammary gland and milk were not significantly different between the control and clofibrate groups. There were, however, positive linear correlations between liver SCD mRNA and hepatic 16:1/16:0 FA ratio (r =0.495, P<0.05), 18:1/18:0 FA ratio (r =0.520, P<0.05) and milk 16:1/16:0 FA ratio (r =0.552, P<0.05). In a second trial, four groups (n=6) of lactating Swiss mice were used to compare the effect of clofibrate ingestion (control diet v. diet containing clofibrate (0.05% w/w)) and clofibrate injection (olive oil vehicle subcutaneously v. 15 mg clofibrate/100g LW in olive oil subcutaneously) for 7 days. Mammary SCD mRNA, but not liver SCD mRNA, was induced by ingested and injected clofibrate (P<0.05), compared to their control treatments. FA composition of liver, mammary gland and milk was not affected by either treatment. Correlations between mammary SCD mRNA and mammary tissue 16:1/16:0 FA ratio (r =0.660, P<0.05), and 18:1/18:0 FA ratio (r =0.59, P<0.05) were significant in the group ingesting clofibrate. Liver SCD mRNA for both treatments and mammary SCD mRNA for the injected group were not significantly correlated with FA composition. It was concluded that female mice that are lactating may be less sensitive to the effects of clofibrate than male mice. In the preliminary trial, SCD mRNA transcription was induced (P<0.05) 2.1 fold in the mammary gland and 5.3 fold in the liver (P<0.05) of the mice fed the fat free diet over the control treatment. Induction of transcription was not transmitted to an effect on the FA composition of the liver, mammary gland or milk. However, there was a trend (P<0.10) for milk 16:1/16:0 FA ratio to be increased in the fat free treatment over the control treatment. Liver SCD mRNA was correlated (r =0.552, P<0.05) with milk 16:1/16:0 FA ratio, liver 18:1/18:0 FA ratio (r =0.520, P<0.05) and liver 16:1/16:0 FA ratio (r =0.61, P<0.05). In a third trial, lactating Swiss mice were allocated to three groups (6 mice/group) which were either fed a fat free diet, a safflower oil diet (25% w/w) or an olive oil diet (25% w/w) over a 7 day period. The safflower oil diet was included because polyunsaturated FA inhibit SCD activity in the liver while a fat free diet stimulates its activity. The olive oil treatment was included as a reference point with which to compare the responses to the other treatments. In the event, the intake of polyunsaturated FA by the mice on this diet may have been sufficient to inhibit the induction of SCD mRNA so that only relative responses between the various diets could be considered. Mammary SCD and liver mRNA transcription levels were greater in the fat free treatment (P<0.05), compared with the olive and safflower oil treatments. Mammary SCD enzyme activity was not significantly affected by treatment., The fat free treatment increased liver 16:1/16:0 FA ratio and 18:1/18:0 FA ratio (P=0.05) and the mammary 16:1/16:0 FA ratio (P<0.05) but not the 18:1/18:0 FA ratio compared with the other two diets. The olive oil treatment increased palmitoleate and oleate concentration in the liver, mammary gland and milk (P<0.05). The increase in the concentration of oleate reflected the composition of the olive oil in the diet. Similarly, dietary intake influenced the significantly greater proportion of linoleate in the milk of the safflower treatment (P<0.05). The oleate concentration, 16:1/16:0 and 18:1/18:0 FA ratios were greater (P<0.05) in the milk of the group fed the fat free diet than those in the milk of the group on the safflower oil diet. An accumulation of stearate (P<0.10), indicating SCD inhibition, was present in the milk of the safflower oil treatment compared to the fat free treatment. The proportion of saturated fatty acids from octanoate to palmitate was greater in the milk from the mice on the fat free diet compared with those on the safflower oil treatment. The proportions of long chain fatty acids of molecular weight greater than linoleate were higher in the milk from the mice fed the diets containing the oils.Item Milkfat - vegetable oil blends for the manufacture of Danish pastry margarine : a thesis presented in partial fulfilment of the degree of Master of Technology in Food Technology at Massey University(Massey University, 1983) Chin, Pearl Wing MingLegally, butter must contain at least 80% fat (all of which must be pure milkfat) and a maximum of 16% water. As a consequence of these legal restrictions, there has been a reluctance for the dairy industry to blend oils with milkfat since products like this cannot be termed as butter. However, in recent times there has been some interest in the mixing of milkfat and vegetable oils for dairy spreads. An example of this type of product is "Bregott" made from an 80:20 milkfat: oil mix (Anon, 1969) manufactured in Sweden and claimed to have superior spreading properties over normal butter. The blending of milkfat and oil for reasons other than improving spreadability has not been extensively researched. It would seem advantageous to incorporate milkfat into cake and pastry margarine to enhance the flavour of the end products, although the high cost of milkfat in some countries may prevent this from becoming commercially feasible. In New Zealand, milkfat is relatively cheap and it may be possible to produce a cake or pastry margarine containing a significant amount of milkfat at a competitive price. This type of product could capture a segment of the commercial baking industry which is at present monopolised.Item Phenotypic relationship between milk fatty acid profile and live weight change in early lactation in New Zealand dairy cattle : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science, Institute of Veterinary, Animal and Biomedical Sciences, Palmerstone North, New Zealand(Massey University, 2016) Mkunda, VedastusThe phenotypic relationship between milk fatty acid (FA) profile and live weight (LW) change in early lactation in grazing Friesian x Jersey (FxJ) cows was investigated in this study. Data used in this study compromised of 73,040 daily milk yields, 5,936 fortnightly herd-tests for fat, protein and lactose, 41,981 daily live weights, and 882 determinations of FA profiles from 300 second-lactation FxJ crossbred cows recorded during the production season 2003-04. Cows were classified based on the magnitude of LW change from calving to peak lactation into three groups: cows with low live weight loss (L; below -0.012kg), medium live weight loss (M; below -0.174kg and high live weight loss (H; below -0.340kg). LW change was considered as a proxy for energy balance. Correlations between LW change and individual FAs or group of FAs were estimated at the three stages of lactation (early, mid and late). Stage of lactation affected significantly (P>0.05) the concentration of all FAs considered in this study, except the concentration of C20:0. Higher concentration of C18:0 and C18:1 cis-9 was observed in early lactation relative to other lactation stages. Compared to the L and M cows, the H cows had higher concentration of C18:1 cis-9 in early lactation. Live weight loss in early lactation was significantly associated with higher concentrations of unsaturated (r = -0.19), long-chain FA (r = -0.17), C17:0 (r = -0.14), C18:1 cis-9 (r = -0.20) and C18:3 cis-9, cis-12, cis-15 (r = -0.21), but live weight loss was significantly associated with lower concentrations of saturated FA (r = 0.18), medium-chain FA (r = 0.16), C12:0 (r = 0.24), C14:0 (r = 0.17) and C15:0 (r = 0.22). The association between LW changes in early lactation and most of the FAs were not significant in mid and late lactation. If determination of FA can be implemented using mid-infrared spectroscopy, a conclusion from this study is that concentration C18:1 cis-9 in early lactation can be used as indicator of live weight change (energy balance). Further studies are required to evaluate the inclusion of concentrations of FAs in breeding programs to improve fertility in seasonal grazing dairy cattle.Item A new technology for milkfat : thesis submitted for the degree of Master in Food Technology at Massey University(Massey University, 1993) Teo, Cheng TetMilkfat is one of the most complex of all fats, consisting of numerous different triglycerides as well as complex fats, such as phospholipids and cerebrosides, and traces of mineral substances (Walstra and Jenness, 1984). It is liquid above 40°C and usually completely solidified below -40°C. At intermediate temperatures, it is a mixture of crystals and oil, the oil being the continuous phase. On cooling, a liquid fat usually forms small crystals at first (in rapid cooling, often in α modification) of needle to platelet shape, 0. 1-3.0μm long, with a ratio length:width:thickness of 4:2:1, (Jensen, 1967). As crystals grow, similar shaped but larger crystals in aggregate which can be as much as 50μm across, are formed. Crystallisation is initiated by the presence of suitable crystal nuclei (centres of crystallisation) in the liquid fat as a few molecules gather in molecular aggregates where the potential energy is reduced to the minimum. Lowering of temperature strongly influences the rate of nucleus formation. Homogeneous nucleation occurs when crystals nuclei are formed spontaneously from a pure melt. Usually a supercooling of 3-5°C is needed to start a nucleation, and a further temperature decrease by a few degrees can caused rapid nucleation. In practice, for fat in bulk, nucleation is always heterogeneous, i.e. crystallisation always starts at the surface of extraneous particles, often called catalytic impurities (Skoda el at, 1963).Item Determining premium payments for concentration of unsaturated fatty acid in milkfat in New Zealand based on changes in farm and processor profit : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand(Massey University, 2014) Silva Villacorta, DavidNiche markets have emerged for dairy products with a high concentration of unsaturated fatty acids (UFA) in milkfat. Several studies have indicated that although milkfat UFA concentration could be increased on-farm by manipulation of the diet and genetic selection, farm profit could be negatively affected in the absence of a premium for milkfat UFA concentration. The objective of this study was to estimate, via simulation, a premium for milkfat UFA concentration, for dairy farmers in New Zealand that segregate cows, or feed oilseed supplements to dairy cows, to produce milk high in UFA. Data from New Zealand Holstein-Friesian cows were used to develop a stochastic farm model that simulated the physical and financial performance of dairy farms under New Zealand conditions. The farm model was then used to simulate a population of 1,820,000 cows and 5,600 dairy farms. From the population simulated, the top 17,150 cows for milkfat UFA concentration were segregated and randomly distributed onto 50 farms (UFA farms). The farm model was also used to simulate a group of 50 farms on which an oilseed supplement was fed to dairy cows during lactation (OILSEED farms). The characteristics of UFA farms and OILSEED farms were compared with those of 50 average farms (AVE farms). A deterministic milk processing model was used to simulate a dairy processor that processed and marketed the milk produced by AVE farms, UFA farms and OILSEED farms. A milk payment system which paid dairy farmers for milkfat ($/kg), protein ($/kg) and milkfat UFA concentration ($/kg milkfat), but penalised milk volume ($/L), was developed using data corresponding to the physical and financial performance of the dairy processor and the three groups of dairy farms simulated. In the absence of a premium for milkfat UFA concentration, the operating profit ($/ha) of UFA farms and OILSEED farms was significantly lower than that of AVE farms. For UFA farms, a premium of $0.47 to $0.51 /kg milkfat for each 0.1 g UFA/100 g milkfat increase (above 34.50 g UFA/100 g milkfat) equalled their operating profit ($/ha) to that of AVE farms. For OILSEED farms, a premium of $0.10 to $0.14 /kg milkfat for each 0.1 g UFA/100 g milkfat increase (above 37.50 g UFA/100 g milkfat) equalled their operating profit ($/ha) Abstract ii to that of AVE farms. These premiums for milfat UFA concentration could help New Zealand dairy companies to further evaluate whether it is economically viable producing and processing milk high in UFA. Keywords: unsaturated fatty acids, stochastic farm model, milk processing, premium, milk payment.