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From first bite to swallow initiation : an evidence-informed assessment framework for transitional foods in Dysphagia management : a thesis presented as fulfilment of the requirements for the degree Master of Speech and Language Therapy at Massey University, Albany, New Zealand
(Massey University, 2025) Muthumudalige, Samurdi Darshika Perera
Transitional foods, foods that undergo textural transformation from one texture to another through moisture or temperature changes during consumption, represent a promising dysphagia management approach, yet systematic evaluation frameworks specifically addressing transformation mechanisms are lacking. Current texture-modified food assessment practices focus predominantly on initial texture properties and pharyngeal safety outcomes, with limited attention to oral-stage transformation processes that define transitional food effectiveness. This study developed an evidence-informed evaluation framework for transitional foods through rapid systematic review and thematic synthesis of texture-modified food assessment literature. Systematic searches across four databases (PubMed, CINAHL, Cochrane Library, Scopus) identified 28 studies examining oral processing assessment approaches in texture-modified foods for adult populations. Data extraction systematically captured assessment components, methods, population characteristics, and quality indicators. Methodological quality was appraised using the Critical Appraisal Skills Programme tool and a purpose-developed assessment schedule, with thematic synthesis conducted using NVivo to identify patterns characterizing current assessment practices and gaps requiring framework specification. Systematic extraction identified 121 distinct parameters across nine conceptual domains. Assessment concentrated in rheological properties (43%), oral biomechanics (43%), and pharyngeal efficiency (43%), while transformation dynamics (29%) and saliva interaction (21%), the primary mechanisms distinguishing transitional foods from static texture-modified foods, remained substantially underrepresented. Quality appraisal revealed strong measurement practices (76% average measurement quality score) but design transparency gaps, with 82% of studies conducting reliability procedures yet only 18% reporting statistical reliability metrics. Only three studies specifically examined transitional foods as defined by IDDSI, necessitating framework development from broader texture-modified food literature. Thematic synthesis revealed six overarching patterns: safety-focused assessment highlighting underdeveloped oral transformation measurement; rheological testing dominance with static measurement bias; balanced method distribution masking functional imbalance across assessment stages; high-quality studies demonstrating methodological strengths alongside reporting gaps; multi method triangulation concentrated in established domains with limited integration of transformation mechanisms; and IDDSI framework adoption primarily for texture classification (46% of studies) with limited application as a measurement tool for transformation assessment (14%). These synthesis findings directly informed development of an eight-domain Evidence-Informed Transitional Food Assessment Framework addressing identified gaps through accessible, evidence-based methods. The framework mandates pre/post texture comparison to validate transformation occurrence, incorporates gravimetric saliva interaction assessment using precision scales, operationalises IDDSI testing as transformation measurement applicable to expectorated bolus, and integrates patient centred sensory evaluation alongside safety validation. The framework provides clinicians, researchers, and food industry stakeholders with evidence-based methods for systematic transitional food evaluation using globally accessible approaches, supporting evidence-informed food selection, prescription, and product development in dysphagia management.
The competitive adsorption of surfactants in model dairy emulsions : a thesis presented in partial fulfillment of the requirements for the degree of Master of Food Technology at Massey University, Palmerston North, New Zealand
(Massey University, 2025) Tohi, Ahotau Falemaka
Emulsion structure is an important factor effecting the properties and stability of dairy products. The formation of new surface area and the adsorption of emulsifiers in the homogenizer influences the final particle size distribution. In addition, this provides insight on what surfactants may be present on the oil droplet surface. This in turn effect what interactions might occur between droplets, the surfactants and other components in the product. Often there are multiple potential surfactants in the system and the ability to predict which will adsorb onto newly created oil droplet surface area is valuable. The objective of this study was to investigate how mixtures of dairy proteins and chemical surfactants stabilize oil droplet surfaces during emulsion formation. Characterizing the surface loading and emulsion surface areas were done in a simple oil-in-water emulsions with WPI and Tween. Initial investigations were carried out to characterize the emulsion structures formed with Tween surfactants. There were several factors limiting the minimal particle size and amount of new surface area created through high pressure homogenization stabilized by Tween. Two different types of Tweens were used to at various surfactant concentrations at 200 bar for 3 passes to determine the particle size distribution and specific surface area. There were no differences between Tween 60 and 80 emulsions. At concentrations above 3% Tween (wt%/oil) minimal changes in particle size and surface area were observed. Similarly, no significant difference was observed when oil concentration was adjusted from 15% to 40% at the same surface area to volume ratio. Further, the effect of temperature from 40°C to 70°C showed minimal differences in specific surface area and particle size. Under these conditions where there is excess surfactant present, the specific surface area created is limited by the capacity of the homogenizer to further break up particles. At high surfactant concentration 5% Tween 60 (wt%/oil) the effect of increasing homogenization pressure was linear and if higher pressure is used, additional surface area may be created. At low surfactant concentration (less than 2% Tween 60 wt%/oil), the limits of new surface area are attained at 100-200 bar (3 passes) due to the availability of surfactant where increasing pressure or number of homogenizer passes showed minimal change in specific surface area and particle size. The surface coverage of emulsion was in approximate agreement with a theoretical CMC model that measures the critical micellar concentration (CMC) which is a specific concentration for surfactants in solution above which forms micelles. The model assumes a theoretical area covered by each molecule of Tween. When Tween emulsions were created in the presence of excess whey proteins, more complex absorption behaviour occurred. At high Tween concentrations, the specific surface area created was similar to what occurred in the absence of whey proteins. At low Tween concentrations there was evidence of coalescence as bimodal particle size distributions were found, and the specific surface area was lower than what could be achieved in the same conditions in the absence of Tween. These observations were extended by measuring the protein loading, adsorbed onto the oil droplet surface. The mass of protein adsorbed per area of oil droplet decreased as Tween concentration increased, until at about 2% Tween, no whey protein adsorption was measured. In the formation of emulsions at different whey and Tween concentrations, Tween outcompetes whey onto the surface even at very low Tween concentration (0.3% (wt%/oil)). The relative size of whey is large compared to monomers of Tween however the rate of adsorption of whey, suggesting it should adsorb faster. However, Tween forms micelles, even at very low aqueous phase concentrations, and the average size of these micelles are similar or slightly larger than the whey proteins. Conformational changes are required for whey unfold and orientate in order to adsorb onto the oil surface. A Tween micelle can quickly spread on impact which exposes the hydrophobic tails and allows spreading on the surface. For these reasons Tween adsorption dominates the surface of the emulsion even at low concentrations. Only when the aqueous phase of the emulsion is depleted of Tween, does the higher concentration whey protein have a chance to adsorb and contribute to stabilizing surface area created in the homogenizer. As the concentration of Tween increases at 2.2% (wt%/oil), whey is outcompeted completely by Tween onto the surface because there at these concentrations there is enough Tween available to stabilize the surface area that can be created by the homogenizer. The findings of the work suggest how the competitive adsorption between surfactants can be explored to identify how to design emulsions with specific components stabilizing the surface of the oil phase.
The meandering river : an intuitive inquiry of self-compassion in late-diagnosed women with ADHD in Aotearoa, New Zealand : a thesis presented in partial fulfilment of the degree of Master of Science in Psychology at Massey University, Auckland, Aotearoa, New Zealand
(Massey University, 2025) Williamson, Rebekah
This study explores the experiences of self-compassion (SC) in adult women with Attention Deficit/Hyperactivity Disorder (ADHD) in Aotearoa, New Zealand. This was explored using intuitive inquiry as a research method. This method is a compassionate way of engaging with research. Utilising a five-cycle hermeneutic structure, the researcher is invited to engage with their own subjective experience throughout the process, a process which has the potential for personal transformation for the researcher and the participants. The cycles are conceptualised through the metaphor of a river cycle. Seven women with late-diagnosed ADHD described their experiences of self-compassion through semi-structured interviews. Thematic analysis was used to analyse the interview transcripts and highlight themes from the participants. Four integrated lenses were identified. These lenses indicated (a) self-compassion is an embodied transformation process in which the body becomes the site of action; (b) cues for self-compassion were assisted by participants connection to natural rhythms – their own internal cycles, and external natural cycles; (c) conditions for self-compassion supported participants to move towards more accommodating environments and (d) diagnosis is an accelerator of self-compassion.
Continuous high-speed resin 3D printing by interface temperature control : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Albany, New Zealand. EMBARGOED until 15th December 2027
(Massey University, 2025) Collingwood, Jason
The development of high-speed Additive Manufacturing (AM) methods for small, accurate and precise parts is becoming increasingly important as the demand for rapid low-cost AM fabrication continues to grow. Vat photopolymerisation systems offer excellent resolution and accuracy, however their printing speed is often limited by the stiction between the cured resin and the substrate. This stiction restricts how quickly layers can be separated during the printing process and is one of the key limitations preventing the wider adoption of high-speed and continuous 3D printing. This thesis investigates the impact of the substrate temperature on this stiction in bottom-up Digital Light Processing (DLP) systems to understand how temperature influences the stiction between polymerised resin and the substrate and if the peeling operation can be removed by reducing or eliminating stiction. A series of experiments were conducted to understand the stiction impact, followed by preliminary testing on continuous-style 3D printing using the experimental system. Results showed that by lowering the substrate temperature, a reduction in stiction occurred allowing parts to print reliably without becoming stuck to the substrate. It was further shown that warm substrate conditions resulted in the print becoming stuck to the substrate. Following this, successful continuous 3D printing was performed with findings showing that substrate temperature control may be a practical method to support faster printing and may form part of a wider solution in future works on continuous 3D printing systems.
Reuniting families : supporting mothers regaining custody following substance use : a thesis presented in partial fulfilment of the requirements for the degree of Master of Social Work at Massey University, Manawatū, New Zealand
(Massey University, 2026) Hadfield, Susan Winifred
Parents’ substance use is a risk in child welfare cases, exacerbated by poor mental health, adverse childhood experiences, and violence which is further compounded by having multiple children at a young age (Buek & Mandell, 2023). Mothers are required to cooperate with child welfare, when their history supports distrust, and they lack social supports, education, employment, and stable housing. This qualitative research explored ways to support mothers to regain custody of their children following a history of substance use in Aotearoa New Zealand. It considered the difficulties mothers face in family reunification, the services needed to empower mothers towards reunification, as well as post-reunification, to ensure ongoing stability of care. Drawing on social constructionism as a theoretical framework, eight semi-structured interviews were conducted with three groups of participants: mothers, social workers and carers. Key findings include that: mothers face challenges related to addressing historical issues, accessing support, and addressing caregiver concerns; social workers fulfil important roles in working with mothers and prioritise relationship-based practice, support interagency collaboration, and facilitate turning points for mothers. Additionally, the research found that caution is advised when placing children in paternal kinship care when the father perpetrated violence as this can put mothers at risk of further abuse, and that formal support needs to continue for mothers and children post-reunification. This research recommends social workers employ relationship-based practice, consider the ongoing safety of mother and child when placing children in care, and that tailored support for mothers and children be available pre-removal, during separation, and post-reunification.