Sugar esters, substances made from bonding fatty acid tails to a sugar head, can play a number of key roles in food systems from antimicrobial agents to emulsifiers. These unique and very useful properties result from their water-loving and water-avoiding ends. Lactose, a sugar found in milk, based esters are important, as they are environmentally friendly and inexpensive, however, they are not very well understood. I created four different types of lactose esters: lactose monooctanoate (LMO), lactose monodecanoate (LMD), lactose monolaurate (LML) and lactose monomyristate (LMM), and then compared them to each other to see which would be the best emulsifier and which would be the best antimicrobial. My previous studies showed that LML was inhibitory against Listeria monocytogenes a common food pathogen. This encouraged us to evaluated the microbial inhibitory (bacterial killing) properties of LMO, LMD, LMM, along with LML, specifically, the influence of the fatty acid chain length in each ester and how that influenced my results. The esters, in order of highest microbial inhibitory properties, were LML, LMD, LMM followed by LMO. LML was inhibitory against all the Gram- positive bacteria tested including Bacillus cereus, Mycobacterium KMS, Streptococcussuis, L. monocytogenes, Enterococcus faecalis, and Streptococcus mutans but not Gram-negative bacteria (Escherichia coli O157:H7). Sugar esters are a large class of emulsifiers used in the food industry, and so my second research objective was to evaluate the influence of the fatty acid chain length on the emulsification properties of LMO, LMD, LML and LMM and compare them to each other and controls (Tween-20 and Ryoto L-1695) in a standard oil-in-water (O/W) emulsion. I did this by observing how long my emulsions lasted after mixing before they would start to separate. I also looked at the actual size of the oil drops in each of my emulsions, the smaller the oil drops remained, the better they stay in the emulsion and thus the more stable the emulsion. My results showed that the best emulsifier was LML, followed by LMD, LMM, and LMO, respectively. Therefore, my lactose esters contained both microbial inhibitory and emulsification activities. L. monocytogenes is an infamous food pathogen and one of the largest sources of food-borne illness from dairy foods in the United States. Addition of LMD and LML previously were shown to have microbial inhibitory effects in my lab so I wanted to see how well they would work in a food: milk. In general, bacterial deaths in the LMD milk samples were great and many times greater than the LML samples. However, both were greatly affected by milk fat content and how warm each of the samples were kept. LMD may play a useful role in increasing the safety of some foods.

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Lactose is the common disaccharide found in dairy products. It can, however, be a source of discomfort for those whom are lactose intolerant. Therefore, it is necessary to accurately, reliably, and efficiently determine the lactose content of foods. The goal of this research was to develop a reversed-phase HPLC method with UV detection for the determination of lactose. Aminobenzoic acid was used to prepare a derivative, making detection possible in the 300-360 nm region. The stationary phase is a C8 column, with 85% methanol 15% water mixture at pH 5 as the mobile phase. A linear response of peak area to lactose concentration of 0.018 mg/mL to 0.36 mg/mL was obtained with an estimated detection limit of 0.0036 mg/mL lactose concentration. The reproducibility was established with a 4.95% relative standard deviation. The average recovery was 107%, and results were in strong agreement with the standard alkaline ferricyanide method, establishing accuracy.

As a primary factor in human evolution, natural selection is an important component of genetic research. Studies of lactase persistence suggest that positive selection has played a powerful role in the adaptation to a lifelong consumption of fresh milk. Using multiple research studies of lactase persistence and suspected corresponding single nucleotide genetic polymorphisms, this study combines data sources to determine whether evidence exists for natural selection of a specific cytosine-to-thymine genetic mutation located 13,910 base pairs (T-13910) upstream from the lactase gene. This polymorphism has potential to be a causal element for lactase persistence, and data suggest that natural selection has played a role in the rising frequency and distribution of this allele, if only in some regions. European and neighboring regions appear to have the highest frequencies with little or no frequency in Asia, Africa and Indonesia; however the presence of lactase persistence in those areas suggests convergent evolution may be occurring on a phenotypic level. To examine this possibility several other identified polymorphisms in the same region as the T-13910 will be included in this study

The majority of therapeutic pharmaceutical formulations are presented in the solid form. Moisture is able to play an important role in the functional performance of pharmaceutical solids. Moisture profiling is able to provide novel information with regards to the behaviour of moisture within materials using equilibrium relative humidity as a measurement. The hypothesis investigated explores the changes in equilibrium relative humidity of pharmaceutical material induced by physical, chemical or storage conditions, these are able to be monitored using the innovative moisture profiler system. The aims within this were to primarily validate the moisture profiler and secondly evaluate the effects of moisture on physical forms and with respect to effects of compaction, finally this was compared to conventional characterisation methods. Preliminary explorations were conducted in order to assess the validity of the moisture profiler, from this lactose was selected as a suitable pharmaceutical material for further work. Processing effects were then examined, firstly storage at elevated relative humidity of different forms of lactose were explored, and this was carried out with supplementary analysis. Secondly the effects of tabletting were explored, different compaction forces were investigated to observe if this had any notable effects on equilibrium relative humidity of the different lactose forms. Finally subsequent storage of the compacts were examined in order to explore if there were any changes in the equilibrium relative humidity. / EPSRC and Reckitt Benckiser

Although alpacas are not used for milk production a detailed knowledge on the composition of the colostrum and milk is needed for development of colostrum and milk replacers. The aim of the present study was to measure the concentration of fat, protein, lactose, and minerals in alpaca colostrum and milk. Colostrum samples were taken daily over four days after parturition from 20 multiparous alpaca mares. Milk samples were obtained monthly, during the first four months of lactation from 17 alpacas. Composition of colostrum and milk differed in numerous indicators. The concentrations of fat and lactose increased from day 1 (0.5%, 4.0%) to day 4 (5.3%, 5.0%), protein decreased from 20.4% on day 1 to 8.3% on day 4. In milk these three indicators did not change during the lactation. Minerals have been little studied in alpaca colostrum and milk in the past, many of which had the highest concentrations in colostrum immediately after birth. The results of the present study do not support that goat’s milk is the preferred substitute for feeding crias. This study contributes to the knowledge of the composition of alpaca colostrum and milk which can be of particular use in developing replacers.

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Bifidobacteria are the predominant members of the infant gut, colonize adults to a lesser extent, and are recognized as beneficial microbes. Various bifidobacterial species produce ��-aminobutryic acid (GABA), the chief inhibitory neurotransmitter in the mammalian central nervous system. It is postulated that in order to produce GABA, the bifidobacterial genome must contain the gadB and gadC genes which encode a glutamate decarboxylase and a glutamate/GABA antiporter, respectively. Once exported by GadC, GABA is absorbed and transported systemically throughout the host. We hypothesize that specific dietary oligosaccharides will modulate bifidobacterial production of GABA due to varying intracellular concentrations of glutamate. To test this, 33 bifidobacterial strains were screened for GABA production via reverse phase HPLC. Interestingly, 10 strains contained both gadB and gadC genes, but only 8 strains produced detectable GABA in vitro. To further elucidate the extrinsic factors influencing GABA production, strains were subjected to different dietary components. Specifically, lactose and the dietary oligosaccharide FOS were evaluated for the ability to promote biosynthesis of intracellular glutamate and thus potentially GABA. Understanding the relationship between diet, bifidobacterial physiology, and GABA production may inform dietary interventions to modulate this neurotransmitter in vivo.