Department of Wine, Food and Molecular Biosciences

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The Department of Wine, Food and Molecular Biosciences covers course areas including animal and plant science, biochemistry, food science, horticulture, microbiology, sensory science, viticulture and wine science.

Recent Submissions

Now showing 1 - 5 of 827
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    Modulating acidity and bioactivities of sauerkraut with Proprionibacterium freudenreichii : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University
    (Lincoln University, 2024) Luthi, Antonia
    Health and nutrition are inextricably connected, and as consumer demand for health promoting products grows, the food industry is responding with the development of functional foods. Synthetic vitamins are commonly supplemented to maintain good health, particularly Vitamin B12, as it is an essential micronutrient obtained exclusively through the consumption of animal derived foods. This leaves vegans and plant based eaters at risk of deficiency. Studies have shown that Propionibacterium freudenreichii can be successfully co-fermented with Latic acid bacteria (LAB) to produce B12 in grain based substrates. In this study P. freudenreichii was inoculated into a traditional sauerkraut fermentation, resulting in synthesis of B12 at promising levels. Acidity was also modulated when compared with sauerkraut produced by spontaneous LAB fermentation, highlighting the potential for the wider organopleptic appeal of sauerkraut.
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    Studies of bioactive compounds in brown and red onions (skin and flesh) : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University
    (Lincoln University, 2024) Yang, Bo
    Onions (Allium cepa L.) have been cultivated and consumed for thousands of years around the world. The bioactive compounds in onions such as phenolic compounds, are beneficial for the health of humans and can potentially reduce the risk of some diseases, which will lead to longevity of the population. Onion skin is non-edible and is always discarded by consumers and food producers. However, onion waste, mainly consisting of onion skin, is still a rich source of bioactive compounds. Red and brown onion samples in this dissertation were divided into two parts (skin and flesh) and two different extraction methods using two different solvents were tested. Total phenolic content (TPC) and total flavonoid content (TFC) were conducted to assess the bioactivity of onion extracts. The TPC, TFC values were significantly higher in the skin for both kinds of onions (p < 0.05) and 70% ethanol also had a significantly positive effect on the yields of total phenolic compounds and total flavonoids (p < 0.05) compared with reverse osmosis (RO) water. Red onions (both skin and flesh) had higher values than brown onions. Three antioxidant assays (ABTS, DPPH and FRAP assays) were conducted and onion skin also showed higher antioxidant activity than flesh. High performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UPLC) were employed to identify and quantity quercetin in onion skin and flesh. The quercetin content had a similar distribution to TPC and TFC.
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    Novel numerical methods for stochastic ordinary and partial differential equations in modelling complex systems : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
    (Lincoln University, 2023) Tiwari, Parul
    Many natural and engineered systems are complex due to inherent uncertainty. Stochastic Differential Equations (SDEs) and Stochastic Partial Differential equations (SPDEs) provide a rigorous mathematical foundation for modelling these systems. Understanding the dynamics of complex systems under stochastic influences is crucial for predicting system behaviour. Numerical techniques often struggle to handle the complexity and stochastic nature of these equations. This research focuses on adapting and enhancing numerical methods to provide efficient and reliable solutions. The numerical accuracy and stability of these methods are assessed through simulations and examples. This study introduces the synthesis of stochastic spectral methods to solve complex systems by representing random variables as a sum of orthogonal polynomials. We applied Polynomial Chaos Expansion (PCE) methods to contaminant transport problem and to differential equations with random forcing term. We compute the Wick exponentials and show that Wick product coincides with the ordinary product for deterministic functions. We use Malliavin calculus to find the derivatives of a stochastic quantity and are visualised through graphs. We discuss numerical challenges associated with the PCE methods and their solution strategies. In all examples, our chosen method does better and allows us to lead the way in developing robust and efficient strategies to deal with randomness, ultimately enhancing the reliability and resilience of complex systems across various scientific and engineering domains.
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    Identification and characterisation of Saccharomyces cerevisiae strains isolated from spontaneous fermentation of organic Pinot noir wines : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University
    (Lincoln University, 2024) McKendrey, Jayanta Whitley
    This study characterised Saccharomyces cerevisiae populations from the spontaneous fermentation of organic Pinot noir wines produce in Waipara, Aotearoa New Zealand, using a DNA-based Interdelta typing method to evaluate their strain diversity and population dynamics. One hundred and sixty-one S. cerevisiae isolates from key fermentation stages were differentiated by interdelta typing into 106 different genotypes (profiles), of which 24 were observed more than once. One interdelta genotype was observed among each of the fermentation stages studied. The S. cerevisiae population showed a high level of strain diversity with evident dominant groupings of strains during and between fermentation stages. Saccharomyces cerevisiae strain diversity increased towards the end of fermentation accompanied with late-stage dominance by the species. Spontaneous fermentation of organically produced wine may harbour a genetically diverse population of S. cerevisiae strains but appears to be dominated by few genotypes. The influence of each genotype on the organoleptic properties of the eventual product is unknown at this point. However, the use of interdelta typing to identify strains of special relevance with commercial potential is supported.
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    Lamb pH and meat quality: studies on biochemical changes in high pH meat associated with pre-slaughter farmyard stress : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Food Innovation at Lincoln University
    (Lincoln University, 2024) Gibbs, Benjamin Hamish
    Producing meat of the highest quality is of the utmost importance to the red meat industry. This study looked at how energy metabolic changes and protein profiles in sheep were affected by stress before post-mortem, this gave critical insights into lamb meat quality. A study of biochemical shifts related to high-pH lamb meat with pre-slaughter stress was conducted. This study was conducted using a sample of 20, six-month-old ram lambs of the Coopworth breed (two individuals were of mixed Coopworth/Hampshire breeds) that were grazed on pasture until culling. Two treatments of control and stress were applied. The control treatment was minimal stress applied before slaughter, sheep were brought straight through the yards to the slaughterhouse. In the stress treatment, stressful conditions were applied via the use of heading dogs moving the sheep around in the yards for 10 minutes, at 30-minute intervals for 3 hours before slaughter. This caused an elevated metabolic rate in these individuals pre-slaughter. Animals were harvested immediately and tissue samples were snap frozen at -80 °C. Energy metabolic changes of the two intermediate twitch muscles Gracilis (G) and Semimembranosus (SM) were studied through the use of a D-Glucose and L-Lactic acid assay. A non- significant difference was seen in the muscles G and SM for their total glycogen levels between the stress and control treatment. In the lactic acid assay, a non-significant difference was seen in the total lactic acid levels between the two muscle fibres between the stress and control treatment. For the protein profile analysis, it was decided to study four muscles, the previous two mentioned, as well as the fast-twitch muscle Longissimus lumborum (LL) and the slow-twitch muscle Supraspinatus (SS). The protein profiles of these muscles were studied through the use of a Bradford protein determination assay and gel electrophoresis imaging. The Bradford assay revealed that there was no relationship between the total soluble protein concentrations and the stress treatment in all four of the muscle fibres. The gel electrophoresis images when analysed showed a significant difference in the relative frequency of two protein bands at around 100 and 16 kDa in the two muscles SM (P-values 0.05 and 0.01) and LL (P-values 0.03 and 0.05). These results show the potential effect of stress on protein profiles, however further protein sequencing is needed before further conclusions can be made. An analysis of post-mortem pH values was also conducted from measurements after 90 minutes and 24 hours post-mortem (ultimate pH). A non-significant difference was seen after 90 minutes but, a significant difference was seen after 24 hours between all four muscle fibres and stress. Stressed carcasses had significantly higher pH values. Notably the slow twitch muscle SS exhibited higher ultimate pH values while the fast twitch LL muscle exhibited lower ultimate pH values. This indicated a fibre-type-specific response to the stress treatment in the muscle samples studied. Overall this study provided valuable insights into biochemical shifts occurring in sheep muscles under stress conditions. Further understanding of these processes is vital for the meat industry especially for the correct grading of meat before export/ sale. Future studies should look at sequencing the specific proteins that affect the stress treatment to see if they are related to meat quality parameters such as colouring, tenderness and the water-holding capacity (WHC) of meat.