Tuwhera Research Repository

The Tuwhera Research Repository provides sustainable open access and archiving to a broad range of AUT produced research - theses, research outputs and datasets.

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Access status: Open Access ,
Brewer’s Spent Grain as a Substrate for Lactic Acid Fermentation: Contrasting Performance of Lacticaseibacillus rhamnosus and Limosilactobacillus fermentum
(MDPI AG, 2026-10-19) Ha, Minh Quoc; Nguyen, Phuc Hanh; Billardey, Allan; Moulin, Solene; Him, Hui Shing; Kam, Rothman; Seale, Brent; Bang-Berthelsen, Claus Heiner; Le, Thao T
<jats:p>Brewer’s spent grain (BSG), the major by-product of the brewing industry, has attracted growing interest in valorisation through lactic acid bacteria fermentation. However, research has largely focused on Lactiplantibacillus plantarum, while other species have mainly been investigated using enzymatic hydrolysates rather than intact solid BSG. This study compared the solid-state fermentation performance of Lacticaseibacillus rhamnosus ATCC 7469 and Limosilactobacillus fermentum ATCC 9338 on BSG over 10 days. In vitro antioxidant, antidiabetic, anti-obesity, and antimicrobial activities were assessed every two days and integrated into a global bioactivity score. Lacticaseibacillus rhamnosus successfully colonised the substrate, reaching 9.62 log10 CFU g−1 on Day 2 and reducing the pH to 3.6. Antioxidant capacity peaked on Day 2, whereas antidiabetic and anti-obesity activities peaked on Day 10. Bactericidal activity was also confirmed in a bread-simulating matrix, and the global bioactivity score identified Day 2 as the highest-scoring endpoint. In contrast, Limosilactobacillus fermentum failed to establish a successful fermentation, with polymicrobial contamination observed from Day 4 onwards. To investigate whether substrate sterilisation could improve Limosilactobacillus fermentum fermentation performance, autoclaving and a two-step heat treatment were evaluated. Although autoclaving effectively sterilised the substrate, it reduced the number of detectable proteins by nearly 25%, whereas the two-step heat treatment preserved the protein profile but did not support successful fermentation by Limosilactobacillus fermentum. Overall, these findings identify Lacticaseibacillus rhamnosus as a promising candidate for BSG valorisation and underscore the importance of strain selection, as fermentation performance can vary substantially among lactic acid bacteria.</jats:p>
Access status: Open Access ,
Can Lateral Cyclic Reactive Jump Ability Be Reliably Measured Using an Inertial Measurement Unit?
(MDPI AG, 2026-10-15) Michalak, Margaret M; Ryan, Chloe M; Ehlert, Alex; Lian, Yuxiao; Slocum, Christopher; Bennett, Leslie; Villarreal, Hailey; Cronin, John
Jump testing is widely used to assess lower-limb power, force absorption, and stretch-shortening cycle (SSC) function; however, lateral cyclic tests remain underexplored despite their relevance to change-of-direction performance. This study determined the intra- and inter-session reliability of a novel cyclic lateral leg power test using an inertial measurement unit (IMU). Seventeen female athletes completed three identical testing sessions separated by seven days. Participants performed 10 consecutive lateral bounds at distances of 1.0×, 1.25×, and 1.5× leg length on each limb. A foot-mounted inertial measurement unit (IMU) (Output Sports Ltd., Dublin, Ireland) quantified contact time (CT) and air time (AT), with the five shortest values for each variable analyzed. Reliability was assessed using percent change in the mean, coefficients of variation (CV), and intraclass correlation coefficients (ICC). Between-session changes were small (−7.9% to 6.6%), with no significant session effects for CT or AT. CVs ranged from 9.2% to 21.8%, with only CT at 1.0× leg length between Sessions 1 and 2 below 10%. ICCs ranged from 0.12 to 0.76, indicating poor-to-good relative reliability. Overall, the IMU-instrumented lateral cyclic test demonstrated largely unacceptable reliability, particularly at greater jump distances, indicating that further protocol refinement is required before implementation in clinical or performance settings.
Access status: Open Access ,
Navigating Institutional Terrains: Home-Country Institutional Agent Boundary Spanning and Brokerage in SME B2B Internationalization
(Emerald, 2026-10-20) Lindsay, Valerie; Rod, Michel; Ashill, Nicholas; Raskovic, Matt
Purpose Grounded in the theoretical foundations of institutions, boundary spanning and brokerage and SME internationalization, the purpose of this paper is to examine how home-country institutions (HCIs) facilitate the post-entry internationalization of small and medium sized enterprises (SMEs) through home-country institutional agents (HCIAs) in a business-to-business (B2B) context. The authors seek to explore how HCIs influence post-entry SME internationalization through the boundary spanning and brokerage activities of the agents that represent them. Design/methodology/approach The authors present a qualitative study exploring the boundary spanning and brokerage activities of HCIAs located in both the home and host country using 100 in-depth, semi-structured, elite informant interviews. This study explores how HCIAs influence the type and nature of institutional support for post-entry internationalization of SMEs from the home country of New Zealand to the two large emerging host markets, China and India. They offer a novel perspective by investigating the role of HCIAs, representing institutions at the micro level and operating in both home and host country, in supporting the internationalization of SMEs. Findings The findings of this study demonstrate that HCIAs, working in both home and host country locations, assume boundary spanning and brokerage roles when connecting SMEs with relevant actors to supply the requisite knowledge for successful post-entry internationalization. Key findings highlight how specific HCIAs, representing a range of HCIs, facilitate institutional support to SMEs in their post-entry development. This study explores the mechanism of boundary spanning and brokerage used by these agents in connecting relevant actors involved in the internationalization of SMEs from New Zealand to China and India. This study demonstrates how specific HCIA types, different boundary spanning activities and the home or host country location of the agents of the HCIs facilitate this process. Originality/value The authors offer a novel micro-level examination of institutional support for SME internationalization, focusing on the activities of specific agents representing their respective HCIs. This study shows that these HCIAs use boundary-spanning and brokerage activities to connect and facilitate key interactions between SMEs and relevant actors in the host market. Further, the authors highlight the little explored roles and activities of HCIs located in the host market in the context of SME internationalization. Specifically, they show different contributions by home and host-based institutional agents and differentiate between the types of boundary spanning objects used and the associated outcomes for the SMEs. The originality of the findings of this study is evident in their contributions to the institutional, boundary spanning and brokerage and SME internationalization theoretical domains.
Access status: Open Access ,
Application of Relative Energy Deficiency in Sport (REDs) Guidelines: A Scoping Review
(Frontiers Media SA, 2026-10-19) McGahan, Paula; Carroll, Matthew; Molyneux, Prue
Introduction: Relative Energy Deficiency in Sport (REDs) is a multifactorial syndrome arising from low energy availability (LEA), leading to physiological, psychological, and performance impairments. Despite established clinical guidelines, integration into research is uneven, demonstrating a research-translation delay. This scoping review aimed to map how REDs guidelines have been operationalised in research and assess the consistency of their application across studies.Methods: Following the Preferred Reporting Items for Scoping Reviews, a systematic search of Medline, CINAHL, SPORTDiscus, and Scopus was conducted on 21 September 2025.Results: Thirty-two studies met the inclusion criteria. Twenty-six used mixed Triad/RED-S/REDs terminology, and twenty-six post-2014 studies continued using Triad terms. Five studies followed the Triad framework alone, seventeen studies followed a parallel use of Triad-based models alongside the 2014 and/or later IOC REDs guidelines. LEAF-Q appeared in fifteen studies, only one CAT2. REDs awareness ranged from 10% to 92% across samples.Discussion: Overall, inconsistency in REDs terminology, screening and operational use of REDs guidelines is apparent in research, highlighting the need for standardised concepts and improved temporal delays in research-translation to support contemporary REDs research and ultimately strengthening athlete health outcomes.
Access status: Restricted ,
Investigating, Characterisation and Development of a Biocompatible Material for Biomedical Graft Applications
(Auckland University of Technology, 2026) Biddick, Samuel; Meshkinzar, Ata
Cardiovascular disease remains a leading cause of death worldwide and coronary artery bypass grafting is a common surgical treatment for advanced coronary artery disease. Natural conduits such as internal thoracic artery and saphenous vein remain the clinical standard; but their limited availability and quality drive the need for a synthetic small diameter vascular graft. The central obstacle to developing such a graft is compliance mismatch, existing synthetic materials such as ePTFE and Dacron are considerably stiffer than the native coronary artery. This inability to replicate its compliant, nonlinear mechanical response, generate stress concentrations at the anastomosis that lead to graft failure. This thesis investigates a series of solution cast TPU:PDMS:EMA polymer blends as candidates for graft materials, there are nine compositions across three blend ratios (90:10:1, 80:20:1 & 70:30:1) with three casting concentrations (10,15, & 20% w/v). The mechanical properties were determined using standardised ISO 37 type 2 dumbbell specimens alongside stepped specimen geometry designed to investigate the effect of a geometric discontinuity on the mechanical properties and performance. The blends exhibited ultimate tensile strengths of 19.33 to 27.76 MPa and elongations at break exceeding 898%, comfortably surpassing both native coronary artery tissue and autologous vessels, however at the same elongation at break as the natural vessels, the blends exhibited the same tensile stress. All compositions displayed a progressively softening mechanical response with secant modulus declining across the deformation range. This profile is fundamentally more favourable for compliance matching than the near consistent stiffness of conventional synthetic grafts. The stepped specimens demonstrated that geometric transitions dictate the site and mode of failure independently of bulk material properties. The 90:10:1 15% w/v blend emerged as the most mechanically well-rounded composition. These findings establish the TPU:PDMS:EMA system as a promising candidate for continued development toward small diameter vascular graft applications.