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Suitability of Recombinant Lipase Immobilised on Functionalised Magnetic Nanoparticles for Fish Oil Hydrolysis
(MDPI (Basel, Switzerland), 2019-05-03) Verma ML; Rao NM; Tsuzuki T; Barrow CJ; Puri M
Recombinant Bacillus subtilis lipase was immobilised on magnetic nanoparticles by a facile covalent method and applied to fish oil hydrolysis. High loading of enzyme to the functionalised nanoparticle was achieved with a protein binding efficiency of 95%. Structural changes of the confined enzyme on the surface of the nanoparticles was investigated using transmission electron microscopy and spectroscopic techniques (attenuated total reflectance-Fourier transform infrared and circular dichroism). The biocatalytic potential of immobilised lipase was compared with that of free enzyme and biochemically characterised with respect to different parameters such as pH, temperature, substrate concentrations and substrate specificity. The thermal stability of functionalised nanoparticle bound enzyme was doubled that of free enzyme. Immobilised lipase retained more than 50% of its initial biocatalytic activity after recyclability for twenty cycles. The ability to the immobilised thermostable lipase to concentrate omega-3 fatty acids from fish oil was investigated. Using synthetic substrate, the immobilised enzyme showed 1.5 times higher selectivity for docosahexaenoic acid (DHA), and retained the same degree of selectivity for eicosapentaenoic acid (EPA), when compared to the free enzyme.
A screening approach for assessing lytic polysaccharide monooxygenase activity in fungal strains
(BioMed Central Ltd, 2019-12-01) Dixit P; Basu B; Puri M; Tuli DK; Mathur AS; Barrow CJ
Background: Efforts to develop efficient lignocellulose-degrading enzymatic preparations have led to the relatively recent discovery of a new class of novel cellulase boosters, termed lytic polysaccharide monoxygenases (LPMOs). These enzymes are copper-dependent metalloenzymes that initiate the biomass deconstruction process and subsequently work together with cellulases, hemicellulases, and other accessory enzymes to enhance their hydrolytic action. Given their wide distribution and diversity, screening and isolation of potent LPMOs from natural fungal diversity may provide an important avenue for increasing the efficiency of cellulases and thereby decreasing cellulosic ethanol production costs. However, methods for quick screening and detection are still not widely available. In this article, a simple and sensitive method is described by combining nonhydrolytic activity enhancement followed by LC-MS-based quantitation of LPMOs. Results: In this study, a screening approach has been developed for the detection of nonhydrolytic cellulase-enhancing enzymes in crude fungal supernatants. With the application of a saturating benchmark cocktail of Celluclast 1.5L, fungal isolates were selected which had the capability of hydrolyzing pretreated rice straw by their synergistic enzyme fractions. Subsequently, these fungal extracts along with an LPMO-enriched commercial enzyme were investigated for their ability to produce Type I LPMO activity. An LC-MS-based methodology was applied to quantitate gluconic acid in enzymatic hydrolysates as an indirect measurement of Type I LPMO activity. Conclusion: The present study describes an LC-MS-based separation method to detect and quantitate LPMO activity in a commercial enzyme. This method was also applied to screen fungal extracts. The developed screening strategy has enabled detection of LPMO activity in two industrially important Penicillium strains.
Characterization of Colocasia esculenta L. Schott var. esculenta grown in Tonga for food applications : a thesis presented in partial fulfilment of the requirements for the degree of Master in Food Technology at Massey University, Palmerston North, New Zealand
(Massey University, 2025) Faanunu, Asena Toivaha
This study characterized two Colocasia esculenta L. Schott var. esculenta cultivars, Holoitounga and Lau’ila, focusing on their corms and ungelatinized flours, and evaluated their potential to partially substitute wheat flour in crackers, shortbread biscuits and bread. Fresh corms were analzyed for physicochemical, microstructure, and cooking characteristics, while derived flours were assessed for nutritional composition, microstructure, water and oil absorption properties, pasting behaviour, thermal properties, foaming and emulsion properties and rheological behaviour, including protein fortification with egg white, casein and pea protein. Holoitounga exhibited higher dry matter (38.43 %), amylose content (12.75%), dietary fiber (4.54 g/100g), crude fat (1.76 g/100g) and carbohydrates (89.29 g/100g), with loosely packed starch granules and shorter cooking time (12-14 minutes), whereas Lau’ila had higher starch (68.40 %) and protein contents (3.49 g/100g), higher amylopectin content (90.55 %), and denser microstructure, contributing to longer cooking time (14-16 minutes) and greater cohesiveness. Holoitounga flour showed finer particle size with an average diameter of 74.08 µm, higher bulk density (0.59 g/mL), water absorption index (4.70 g/g), water absorption capacity (94.61 g/100g), oil absorption capacities (92.51 g/100g) gelatinization temperature (78.92 oC) and pasting viscosity (4952.33 cP). Lau’ila, in contrast, displayed higher swelling power (5.64 g/g), water solubility (0.30 g/g) and foaming capacity (7.69 %). Protein fortification significantly improved the rheological properties of both flours, particularly the egg white and casein protein, making them more comparable to wheat flour dough. In bakery applications, low to moderate substitution levels (≤ 50%) maintained acceptable physical, textural, and nutritional attributes with shortbreads and crackers tolerating higher levels (50% - 100%) better than bread. Holoitounga samples consistently outperformed those from Lau’ila in puffiness, colour, and texture, likely due to their higher amylose content. Nutritionally, substitution reduced energy and protein content but increased carbohydrates and sugars, indicating the need for protein enrichment at higher substitution levels. These findings highlight the potential of Tongan taro flours, particularly Holoitounga, in supporting import substitution strategies, while future research should explore storage stability, sensory acceptance, and further protein fortification to enhance their application in gluten-reduced and gluten-free bakery products.
Heat-induced gelation of faba bean and rice protein isolates with egg white powder and hydrocolloids : toward hybrid vegetarian sausages : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology, Massey University, Auckland, New Zealand
(Massey University, 2025) Ortegon, Nardeth M.
This thesis investigated the heat-induced gelation behaviour of two plant-based proteins, faba bean protein isolate (FBPI) and rice protein isolate (RPI), and their functional enhancement through the addition of egg white powder (EWP), modified waxy maize starch (MS), modified potato starch (PS), and methylcellulose (Me). The overarching goal was to develop gel matrices and sausage analogues with improved textural, rheological, and structural properties suitable for meat free alternatives. The experimental work was conducted in three stages. First, the minimum gelation concentrations (MGC) of FBPI and RPI were determined. Results showed that FBPI was able to form stable gels at 12% (w/w), whereas RPI required concentrations exceeding 15% (w/w) and exhibited limited self-gelling capacity. Subsequent, FBPI (12% (w/w)) and RPI (15% (w/w)) dispersions were blended with EWP across a range of ratios at pH 7 to investigate the synergistic effects between plant and animal proteins. Rheological analysis demonstrated that increasing EWP content significantly improved the storage modulus (G′) and reduced the loss factor (tan δ), indicating stronger and more elastic gel networks. Water-holding capacity (WHC), texture profile analysis (TPA), and SEM imaging confirmed that EWP incorporation led to firmer, more cohesive gels with finer, more homogenous microstructures. The second stage aimed to examine the integration of hydrocolloids (MS, PS, Me) into FBPI at 12% (w/w) and RPI at 15% (w/w) matrices to develop heat-induced composite gels. In FBPI systems, Me improved viscoelasticity, while starches contributed to firmness and WHC, with optimal results observed at 5% MS and 10% PS. RPI, which lacked intrinsic gelling capacity, responded more strongly to starch addition, particularly MS, which improved gel structure and stability even at lower concentrations. In the third stage, sausage formulations were developed with high (Me 1.6%, MS 5%, PS 10% (w/w)) and reduced hydrocolloid levels (Me 0.8%, MS 2%, PS 5% (w/w)). Sausages prepared with reduced hydrocolloid levels and supplemented with 8.8% (w/w) EWP (approximately 40% of total protein content) showed a significant increase in protein content and hardness Notably, improvements in chewiness was observed only in the FBPI-H-E sample. This research provides valuable insights into the development of meat free sausages with desirable textural properties, focusing on ingredient formulations and their effects on texture using FBPI and RPI. As sensory evaluation and flavour development were not within the scope of this study, further research is needed to address these aspects by incorporating flavourings to improve overall consumer acceptability.
Sustainable marine bait technology : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology, Massey University, Manawatu Campus, Palmerston North, New Zealand. EMBARGOED until 26th June 2027
(Massey University, 2025) Chua, Jerome
Longline fishing has emerged as a sustainable alternative to set nets and trawling for targeting rig, reducing bycatch and supporting conservation efforts. Rig (Mustelus lenticulatus) is highly attracted to crustacean-based baits and a frozen crayfish waste stream from Fiordland Lobster Company presents an opportunity to develop an alternative bait. This project formulated a bait consisting of three key components: crayfish mince, a matrix forming agent, and sausage casing. The manufacturing process involved standardised mixing, forming, portioning, and conditioning steps. Before sea trials, the formulated baits underwent a simulated sea trial using an orbital shaker to replicate rough sea conditions. Formulations that remained intact on the hook after six hours of seawater submersion were subjected to texture analysis. Additionally, protein leaching rates were quantified and compared to traditional crayfish leg baits to assess their effectiveness in attracting rig. These tests ensure the bait is durable in longlining operations and its effectiveness in attracting fish. Preliminary sea trials were conducted with test baits, allowing fishers to provide feedback for further refinements before scaling up production to 1,000 test baits per production. The scale-up process utilised small-scale food production equipment adapted for laboratory manufacturing. Official field evaluations compared two different formulated baits against control samples across varied environmental conditions, with results indicating improved catch performance for the new formulated baits. Thus, the developed crayfish sausage baits were more effective than control baits in catching both fish and rig. Future studies can adapt this processing method and materials to other seafood waste streams, potentially leading to a new bait manufacturing industry in New Zealand. This would support the fishing sector, reduce waste, and promote sustainable resource utilisation.