Studies of food stickiness in relation to oral processing

It is generally accepted that a food perceived as sticky would adhere easily to oral surfaces (e.g. teeth and soft tissues) and lead to many irregular movements of the jaw and the tongue. However, there are two major issues with this assumption. Firstly, there has been no supporting experimental evidence. Secondly, the stickiness measurements in the research lab are often conducted under conditions very dissimilar to those in the mouth and, therefore, their correlations to oral experience are somewhat questionable. This project investigated food stickiness and its effects on oral experience using three approaches: instrumental characterization, sensory assessment, and oral physiological analysis. Six semi-solid confectionery foods, standardized in size and shape, were used for investigation. Their stickiness was characterized quantitatively using penetration tests performed in a Texture Analyser and evaluated sensorially through assessment by a taste panel of 14 young subjects. Oral response to food stickiness was characterised using surface Electromyography (sEMG) technique to record the activities of major oral/facial muscles. Products were well discriminated not only according to their stickiness but also their hardness. Instrumental characterization of food stickiness was carried out with two different probes: a flat 5mm stainless steel probe and a natural tooth probe, and measured dry and wet to mimic oral conditions. It was found that food products can be categorised into two groups: those in which stickiness increased and those in which the stickiness decreased after surface wetting. The measured wet stickiness exhibited very good correlations with sensory stickiness. Measurements from the sEMG of 10 subjects showed that the activities of oral muscles during mouth closing (masseters and temporalis), mouth opening (digastric muscle), and tongue movements respond directly to food stickiness. Increases in muscle work per chewing sequence W (µV-s) for both opening and clossing muscles were closely associated to the perception of food stickiness rather than with food hardness. Association of muscle activity, of closing muscles, to stickiness sensation is believed to arise from the increased difficulty and uncomfortable sensation of applying shearing action between teeth when the sticky food tends to hold them together

Biomechanical form and function in primate seed predators : common solutions for similar mechanical challenges?

Seed predation, as seen in a diverse range of primate species, is a specialist diet in which seeds are accessed via the breakdown of stress-resistant external protective layers. This diet is considered mechanically challenging, requiring high forces and wide gapes to successfully fracture seed casings and gain access to nutrients. It is expected that seed predators will possess anatomical features which facilitate the breakdown of large, hard items. The biomechanical function of seed predator morphology relative to other primates is not known, nor is it known if members of this group converge on the same morphologies. This study examines the masticatory morphology of a diverse range of primate seed predators by combining 1) geometric morphometrics and convergence testing, 2) biomechanical modelling and 3) direct physical testing of tooth performance.Comparisons between different seed predator masticatory morphologies demonstrate some convergence in shape, but other factors including body size, prognathism, and dental morphology appear to enable different solutions to the same mechanical problem. Smaller-bodied seed-predators primarily show adaptations for high mechanical advantage, while larger-bodied seed predators have large muscle cross-sectional area but low mechanical advantage. The dentition of some seed predators requires less force to fracture hard brittle seeds than non-seed predators. Surprisingly, some non-seed predators also possess features which are advantageous to hard food consumption, while one intensive seed predator has poor performance on nearly all measurements.This study suggests no common solution for seed predation, but instead proposes multiple morphologies capable of meeting the demands of this diet. Results presented here also highlight the need to consider the masticatory system as a whole, as both muscle force capacity and dental occlusal surface impact food breakdown. Without considering these different components of the masticatory apparatus it is not possible to fully appreciate the potential for functional equivalence in this system

Ancestral variation in mid-craniofacial morphology in a South African sample

Ancestry estimation is a critical component of the demographic profile compiled by forensic anthropologists when unknown skeletal remains are discovered. The mid-craniofacial region is most frequently used to estimate ancestry as this region reflects the genetic and morphological ancestry of an individual. The diverse composition of the South African population makes ancestry estimation problematic, and necessitates the development of reliable, population-specific standards. This study sought to characterise variations in mid-craniofacial shape and size between South Africans of European ancestry (EA), African ancestry (AA) and Mixed ancestry (MA). Metric, nonmetric and geometric morphometric assessments were performed on 392 crania from skeletal collections in South Africa. Variations in mid-craniofacial shape and size were assessed in the orbital, nasal, zygomatic and maxillary regions in two-and three-dimensions. Univariate and multivariate statistical analyses were employed to characterise variation and estimate ancestry in AA, MA and EA individuals. Multivariate analyses suggest that tightly integrated ancestral variations in each component of the mid-craniofacial region are associated with functional, regional and developmental proximities of these regions. Specifically, AA individuals exhibited wider and shorter midfacial regions than EA individuals, who exhibited the narrowest orbital, zygomatic and nasal breadths and the longest upper facial, orbital and nasal heights. EA individuals exhibited inferiorly-angled orbits, elongated nasal apertures and anteriorly projecting nasal bridges. Rounder nasal apertures, less anteriorly projecting nasal bridges and more anteriorly projecting maxillary regions were detected in AA individuals. MA individuals exhibited heterogeneity in terms of craniofacial shape and size, and therefore produced the lowest ancestry estimation accuracies. Overall, nasal and maxillary regions were the most ancestrally diverse regions. Antemortem maxillary tooth loss and midfacial trauma were confounding factors in ancestry estimation accuracies. The lowest ancestry estimation accuracies were yielded by two-dimensional metric (27%-60.2%) and nonmetric (57.1%-82.4%) methods. Metric and geometric morphometric assessments yielded the highest repeatability (≥ 95%) indicating that these methods may be more reliable for use in medicolegal contexts. Geometric morphometric shape assessments yielded the highest ancestry estimation accuracies (75-97.9%), suggesting the presence of three dimensional shape variations between ancestry groups. These results suggest that a continuum of ancestral variation, with large areas of overlap, exists across South African populations and emphasises the need to develop multivariate ancestry estimation standards which can estimate ancestry reliably

Assessing primate skull shape variation in relation to habitat: a 3D geometric morphometric approach

The advancement of digital imaging and open-source geometric morphometric (GM) software is positively impacting the way we understand morphological adaptation as an evolutionary response. Shape-space data and multivariate statistics quantify shape variation patterning and, therefore, consolidate hominoid systematic procedures. This thesis identifies ecomorphological patterns of variation within extant primates. Through a comparative, multivariate and geometric morphometric approach, this research provides a better understanding of the effects of the environment on craniomandibular form in early hominins. In this study, 107 cranial and 108 mandible specimens of 9 modern primate species were 3D imaged, and geometric morphometrics statistics were used to quantify and assess the patterns of variation between intra- and interspecific datasets concerning habitat type. Results were visualised through Principal Component scatter plots and Thin-plate Spline deformation warps, which identified critical morphological high-to-low-energy bending areas. This application addressed the questions: • to what extent does ecology influence craniomandibular morphology? • what are the main environmental pressures that encourage morphological variance in hominins? The main methodological aims sought to a) create accurate 3D digital renderings of primate skull specimens and b) define a reproducible geometric morphometric technique, which could be used as a valid and precise statistical procedure for future studies regarding hominin ecomorphology. This was achieved by pilot testing laser scanning hardware, digitising cranial and mandibular specimen, testing 3D scanning accuracy, and the best practice for capturing accurate 3D imagery, e.g. environment, lighting and meshing multiple scans. The pilot phase of this thesis also tested statistical programming toolkits capable of carrying out the finalised geometric morphometric methodology. This was achieved through trials of landmarking and statistical procedures on various data processing software, e.g. Checkpoint, TINA, and MeshLabs. Ultimately, the R Project software and accompanying IDE, R Studio, was used to collect, process and analyse the specimen shape data. This thesis contributes to the study of hominin ecomorphological patterning through a comparative approach investigating primate skull adaptation. The main findings showed habitat type as having statistical significance on the cranium's morphology but quantifiably more so in the mandible, which reported 63.71% of the overall variance observed in the first two Principal Components. This was an increase of 10.44% compared to the interspecific cranial dataset and was supported by Two-block Partial Least Squares and Procrustes ANOVA analysis. The geometric morphometric results showed significant environmental influence on the morphology of the primate cranium, most notably concerned with locomotive functions and visualises a distinction between primates who are more arboreally inclined versus those whose primary form of locomotion is terrestrial. The study also found that dietary specialisations are particularly distinguished by patterns of variation between highly folivorous versus more frugivorous species in both inter-and intraspecific groups

Plant-based yogurts: texture perception and consumer responses

The present study concentrates on the prospects of texture perception and consumer acceptance of plant-based (PB) yogurts. Temporal dominance of sensations (TDS) with consumers (N=87) was used to analyze the dynamic mouthfeel. Following TDS, overall and mouthfeel liking were evaluated using a 7-point hedonic scale. Some PB yogurts were found to be similar by their mouthfeel profile and equally liked as dairy yogurts. Physicochemical properties of the yogurts were also analyzed. Significant differences in flow behavior and small deformation rheology were found between them. Among PB yogurts, thick, creamy, thin, and watery mouthfeel sensations were strongly associated with steady shear rates and apparent viscosity. Large deformation rheology proved to be a useful tool to study PB yogurts. The role of selected factors on mouthfeel perception was studied. Generic descriptive analysis (GDA) and TDS with a trained panel were conducted to study the influence of aroma compounds possibly congruent with sweetness perception (N=10 panelists × 4 sessions). Unflavored and flavored (vanilla; 0.05%; 0.1%; lemon: 0.025%; 0.05%) samples were included. The aromas modified the perceived sweetness in PB yogurts; however, aroma and perceived sweetness did not impact the mouthfeel. The role of product information, visual experience, and cross-cultural differences in mouthfeel perception and consumer acceptance were studied with two identical consumer studies: in the US (n=101) and in Finland (n=96). Six blueberry-flavored yogurts were blended in varying plant-to-dairy proportions. Selected texture-related attributes were studied first by appearance and, after tasting, by mouthfeel using the Rate-all-that-apply (RATA) and Just-about-right (JAR) methods. The results showed that product information did not have an impact on the texture perception. The interpretation of mouthfeel descriptors such as creamy can vary depending on the culture, language and the yogurt market. Texture descriptors were emphasized differently by visual experience and mouthfeel, depending on sample and texture characteristics. In overall acceptance, clear differences were found between the samples: PB-labeled samples with a higher dairy content were most liked, but there were no differences between the countries. Interestingly, the PB-labeled yogurt (50:50) was more liked compared to the same yogurt labeled as dairy yogurt, indicating that consumers have different expectations toward PB and dairy yogurts. Creamy was found to be the main driver of liking among the PB-labeled yogurts in the US and in Finland. The present work lays a cornerstone for the dynamic texture profile and physicochemical properties of PB yogurts in relation to dairy yogurts. The current study contributes to the understanding of the basis of the texture and mouthfeel of PB yogurts. While this thesis focuses on PB yogurts with oat as the main plant ingredient, the results will benefit product development and research on other types of PB yogurts, as well as providing insight to the sensory and physicochemical methods suitable for studying food texture and structure with semisolids. Future studies should focus on the effect of different food ingredients on the texture of PB yogurts, as well as on the preferences of segments of the consumer population.Tutkimus keskittyy kasvipohjaisten jogurttien rakenteen aistimiseen ja hyväksyttävyyteen. Kuluttajaraati (N=87) arvioi viiden kasvi- ja kahden maitopohjaisen jogurtin suutuntumaominaisuuksia syönnin aikana TDS-menetelmällä (eng. Temporal dominance of sensations). Suutuntuma- ja kokonaismiellyttävyyttä arvioitiin 7-portaisella asteikolla. Osa kasvipohjaisista jogurteista koettiin yhtä miellyttäviksi suutuntuman osalta kuin maitopohjaiset jogurtit. Lisäksi jogurttien fysikaalis-kemiallisia ominaisuuksia tutkittiin. Kasvi- ja maitopohjaisten jogurttien välillä havaittiin merkittäviä eroja muun muassa virtauskäyrissä. Kasvipohjaisissa jogurteissa paksu, kermainen, ohut ja vetinen suutuntuma olivat vahvasti yhteydessä tasaiseen leikkausnopeuteen ja viskositeettiin. Erilaisten tekijöiden roolia suutuntuman havaitsemisessa tutkittiin eri tavoin. Koulutettu raati arvioi kuvailevan analyysin ja TDS menetelmän avulla aromiyhdisteiden vaikutusta koettuun suutuntumaan kasvipohjaisilla jogurteilla (n=10 arvioijaa x 4 arviointikertaa). Tutkimuksessa arvioitiin maustamattomia ja maustettuja (vanilja; 0.05%; 0.1%; sitruuna: 0.025%; 0.05%) jogurtteja. Aromit voimistivat makeuden kokemusta, mutta aromi itsessään tai näytteen koettu makeus ei vaikuttanut koettuun suutuntumaan. Jogurtteihin liittyvä kuluttajatutkimus toteutettiin Yhdysvalloissa (n=101) ja Suomessa (n=96). Kiinnostuksen kohteena oli erityisesti tuotetiedon ja jogurtin aistittavien ominaisuuksien vaikutus koettuun suutuntumaan. Kuusi mustikanmakuista jogurttia valmistettiin sekoittamalla maito- ja kasvipohjaista jogurttia eri suhteissa. Valittuja rakenneominaisuuksia arvioitiin ensin ulkonäön ja sitten suutuntuman perusteella kahdella menetelmällä (RATA, eng. Rate-all-that-apply ja JAR, eng. Just-about-right). Tuotteista annettu tieto ei vaikuttanut koettuun rakenteeseen. Ominaisuuksista erityisesti kermaisuus koettiin eri tavalla maasta riippuen, mikä todennäköisesti johtui englannin- ja suomenkielisten termien eroista ja jogurttimarkkinoiden erosta. Maiden välillä ei ollut eroja miellyttävyyden arvioinnissa. Näytteiden välillä havaittiin kuitenkin selkeitä eroja kokonaismiellyttävyydessä: maitopohjaisen jogurtin osuuden kasvaessa näytteiden miellyttävyys vahvistui. Näyte, joka sisälsi puoliksi maito- ja puoliksi kasvipohjaista jugurttia ja joka tarjoiltiin kasvipohjaisena jogurttina, oli pidetympi kuin sama näyte, kun sen kerrottiin olevan maitopohjainen. Tulos osoittaa, että kuluttajien odotukset kasvipohjaisia jogurtteja kohtaan ovat erilaiset kuin maitopohjaisia jogurtteja kohtaan. Kermaisuus oli kasvipohjaisiksi jogurteiksi nimetyissä näytteissä kokonaismiellyttävyyden kannalta tärkeä ominaisuus sekä Yhdysvalloissa että Suomessa. Tämä tutkimus avaa kasvipohjaisten jogurttien rakenteen ja suutuntuman perusteita. Tutkimuksessa selvitettiin kasvipohjaisen jogurtin rakenteen ajallisia muutoksia ja fysikaaliskemiallisia ominaisuuksia suhteessa maitojogurttiin. Vaikka työssä keskityttiin kasvipohjaisiin jogurtteihin, joiden pääainesosana oli kaura, tulokset hyödyttävät myös muiden kasvipohjaisten jogurttien tuotekehitystä ja tutkimusta sekä tarjoavat tietoa puolikiinteiden elintarvikkeiden rakenteen tutkimuksen menetelmistä. Tulevissa tutkimuksissa tulisi keskittyä tarkemmin eri raaka-aineiden ja rakenteen vuorovaikutuksiin sekä kuluttajasegmenttien mieltymyksiin

Novel Techniques in Sensory and Consumer Research Applied to Understand Gluten-Free Products Perception

Tesis por compendio[ES] El trabajo de investigación realizado en esta tesis se ha centrado en la aplicación de técnicas recientes e innovadoras en el estudio de la percepción de productos sin gluten. Primero, se estudió cómo tratar la información que hay en Twitter para conocer las opiniones de los consumidores sobre "sin gluten". Los temas más relevantes fueron 5 productos (pan, tarta, galleta, pizza, cerveza), situaciones de consumo, recomendaciones, lugares y aspectos relacionados con la celiaquía. Para explorar automáticamente la información de Twitter, se estudió utilizar redes de co-ocurrencia, que fueron útiles para interpretar los tweets, representar los aspectos más relevantes (ocurrencia) y ponerlos en contexto y en relación con otros (co-ocurrencia). Se observó que es posible automatizar sin un pre-tratamiento manual, permitiendo analizar de forma efectiva gran cantidad de información disponible online. Después, se estudiaron diferentes panes comerciales sin gluten en cuanto al comportamiento en boca para entender mejor los factores involucrados en la percepción de textura. Los panes (5 sin gluten; 2 normales) se caracterizaron en cuanto a propiedades mecánicas, estructura, fragmentación, saliva incorporada y consistencia y adhesividad del bolo. Las sensaciones de textura variaron a lo largo de la masticación, dependiendo de su estructura inicial, propiedades mecánicas, fragmentación, formación de bolo o actividad oral. Posteriormente, se estudió cómo los cambios en la estructura de panes sin gluten obtenidos por modificaciones en panificación (tiempo de fermentación e hidratación) afectan al procesamiento y actividad oral y las sensaciones de textura, que variaron principalmente según el tiempo de fermentación. Especialmente al principio, las diferencias en las sensaciones de textura se explicaron por las diferencias en la estructura y fragmentación en boca. Por último, se estudió la atención visual (con eye-tracking) y la respuesta de consumidores celíacos a paquetes de pan sin gluten, observando que el tipo de marca y la presencia del logo de certificación sin gluten influían en lo que miran. Todos los panes les dieron confianza, sin afectar la presencia del logo, pero condicionando lo que miran. El tipo de marca afectó la confianza y la expectativa de aceptabilidad, que fueron más altas para marcas específicas de sin gluten. La aceptabilidad también se explicó por otras características de cada pan. Se estudió la atención visual (eye-tracking) y las motivaciones de niños celíacos y sus padres al comprar galletas en comparación con los no celíacos. El patrón de fijación cambió en niños y padres: los niños celíacos se fijaron más en ingredientes, palabras y símbolos sin gluten, y menos en la imagen de las galletas; los padres de niños celíacos se fijaron más en ingredientes y símbolo sin gluten, y menos en la imagen de la galleta, nombre, dibujo e información nutricional. Para todos los niños y padres, lo más importante fue elegir una galleta que les gustara, pero solo los niños celíacos mostraron interés en la marca y por probar un producto nuevo. Otro motivo importante para los padres fue la salud, pero por diferentes atributos (padres de celíacos: certificación sin gluten o lista corta de ingredientes; padres de no celíacos: bajo en azúcar o grasa). El precio o la confianza fueron relevantes solo para los padres de niños celíacos. Esta Tesis ha aportado conocimiento sobre el uso y la practicidad de técnicas recientes en ciencia sensorial y del consumidor. La investigación confirma que se puede conseguir una comprensión plena de la compleja respuesta del consumidor recabando información desde perspectivas muy distintas. Sin embargo, para responder a cuestiones específicas en investigación, cada una de estas técnicas (análisis de las redes sociales, estudio del procesado oral de los alimentos o la técnica eye-tracking) puede contribuir de forma individual a entender mejor la aceptabilidad o la elección de alimentos del consumidor.[CA] El treball de recerca realitzat en esta tesi s'ha centrat en l'aplicació de tècniques recents i innovadores en l'estudi de la percepció de productes sense glútens. Primer, es va estudiar com tractar la informació que hi ha en Twitter per a conéixer les opinions dels consumidors sobre "sense glútens". Els temes més rellevants van ser 5 productes (pa, pastís, galeta, pizza, cervesa), situacions de consum, recomanacions, llocs i aspectes relacionats amb la celiaquia. Per a explorar automàticament la informació de Twitter, es va estudiar utilitzar xarxes de co-ocurrència, que van ser útils per a interpretar els tuits, representar els aspectes més rellevants (ocurrència) i posar-los en context i en relació amb uns altres (co-ocurrència). Es va observar que és possible automatitzar sense un pre-tractament manual, permetent analitzar de manera efectiva gran quantitat d'informació disponible en línia. Després, es van estudiar diferents pans comercials sense glútens quant al comportament en boca per a entendre millor els factors involucrats en la percepció de textura. Els pans (5 sense glútens; 2 normals) es van caracteritzar quant a propietats mecàniques, estructura, fragmentació, saliva incorporada i consistència i adhesivitat de la bitla. Les sensacions de textura van variar al llarg de la masticació, depenent de la estructura inicial, propietats mecàniques, fragmentació, formació de bitla o activitat oral. Posteriorment, es va estudiar com els canvis en l'estructura de pans sense glútens obtinguts per modificacions en panificació (temps de fermentació i hidratació) afecten el processament i activitat oral i les sensacions de textura, que van variar principalment segons el temps de fermentació. Especialment al principi, les diferències en les sensacions de textura es van explicar per les diferències en l'estructura i fragmentació en boca. Finalment, es va estudiar l'atenció visual (amb eye-tracking) i la resposta de consumidors celíacs a paquets de pa sense gluten, observant que el tipus de marca i la presència del logotip de certificació sense gluten influïen en el que miren. Tots els pans els van donar confiança, sense afectar la presència del logotip, però condicionant el que miren. El tipus de marca va afectar la confiança i l'expectativa d'acceptabilitat, que van ser més altes per a marques específiques de sense glútens. L'acceptabilitat també es va explicar per altres característiques de cada pa. Es va estudiar l'atenció visual (eye-tracking) i les motivacions de xiquets celíacs i els seus pares en comprar galetes en comparació amb no celíacs. El patró de fixació va canviar en xiquets i pares: els xiquets celíacs es van fixar més en ingredients, paraules i símbols sense glútens, i menys en la imatge de les galetes; els pares de xiquets celíacs es van fixar més en ingredients i símbol sense gluten, i menys en la imatge de la galeta, nom, dibuix i informació nutricional. Per a tots els xiquets i pares, el més important va ser triar una galeta que els agradara, però només els xiquets celíacs van mostrar interés en la marca i per provar un producte nou. Un altre motiu important per als pares va ser la salut, però per diferents atributs (pares de celíacs: certificació sense gluten o llista curta d'ingredients; pares de no celíacs: baix en sucre o grassa). El preu o la confiança van ser rellevants solo per als pares de xiquets celíacs. Esta Tesi ha aportat coneixement sobre l'ús i la practicitat de tècniques recents en ciència sensorial i del consumidor. La investigació confirma que es pot aconseguir una comprensió plena de la complexa resposta del consumidor recaptant informació des de perspectives molt diferents. No obstant això, per a respondre a qüestions específiques en investigació, cada una d'estes tècniques (anàlisis de les xarxes socials, estudi del processament oral dels aliments o la tècnica eye-tracking) pot contribuir de manera individual a entendre millor l'acceptabilitat o l'elecció d'aliments del consumidor.[EN] The research of this thesis is focused on the application of recent and innovative techniques to study the perception of gluten-free products. First, it was studied how to manage the information available on Twitter to get consumers' opinions about "gluten-free". The most relevant topics when talking about gluten-free on Twitter were five products (bread, cake, cookie, pizza, beer), situations of consumption, recommendations, places, and aspects related to coeliac condition. To automatically explore the information from Twitter, the possibility to use co-occurrence networks was studied. Co-occurrence networks were useful for interpreting tweets' content, representing the most relevant aspects mentioned (occurrence) and putting them into context and in relation to others (co-occurrence). It was found that automated without manual pre-treatment of text is possible, as an efficient analysis of big amounts of online data. Secondly, different commercial gluten-free breads were studied in terms of in-mouth behaviour to better understand the factors involved in texture perception. The breads (5 gluten-free; 2 regular) were characterised regarding mechanical properties, structure, fragmentation, saliva incorporated, and bolus consistency and adhesiveness. Texture sensations varied along mastication, depending on their initial structure, mechanical properties, fragmentation pattern, bolus formation or oral activity. Subsequently, it was studied how changes in structure of gluten-free breads achieved by modifications in breadmaking (fermentation time and hydration) affect oral processing, oral activity and texture sensations. Oral behaviour and texture perception varied mostly according to the fermentation time. Especially at the beginning, differences in texture sensations were explained by the differences in structure and how it fragmented in mouth. Lastly, visual attention (with eye-tracking technique) and response of coeliac consumers to gluten-free bread packages were studied, finding that the type of brand and presence of gluten-free certification logo influenced the visual behaviour. All gluten-free breads were perceived as trustworthy, not being affected by the presence of gluten-free certification logo, but conditioning the visual behaviour. The type of brand affected trust and expected acceptability, being both higher for brands specific of gluten-free. Liking was also explained by other individual characteristics of breads. Visual behaviour and motivations of coeliac children and their parents when purchasing biscuits were studied in comparison to non-coeliac ones. Eye-tracking showed that fixation pattern changed for coeliac children and their parents. Coeliac children fixated more on ingredients, gluten-free words and symbols, and less on biscuit image. Parents of coeliac children fixated more on ingredients and the gluten-free symbol, and less on biscuit image, product name, cartoon, and nutritional information. For all children and parents, liking was the most important reason for choosing a biscuit, but only coeliac children showed interest in brand and unknown products. Other important motivation for parents was health, but the attributes were different (parents of coeliac group: having gluten-free certification or a short ingredients list; parents of non-coeliac group: low sugar or fat contents). Price or trust were relevant motivations only for parents of celiac children. On overall, this Thesis provided knowledge about the usage and practicality of recent techniques or approaches in sensory and consumer science. This investigation confirms that a full understanding of complex consumer's response can be achieved by gathering consumer's information from different perspectives. However, for answering specific research questions, these different tools (social media exploration, food oral processing approach or eye-tracking technique) can individually contribute to better understand consumer acceptability or food choice.Puerta Gil, P. (2022). Novel Techniques in Sensory and Consumer Research Applied to Understand Gluten-Free Products Perception [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182293TESISCompendi

Development, assessment and optimisation of meat systems for the aging consumer through processing and packaging modification

In response to the growing population of those aged over 65, it is essential we prepare for better quality of life not just increased life years. Sensory decline impacts, not just the way we perceive flavours, but the way we see food and the manner in which we handle food. The studies reported in this thesis examined the effects of sensory decline across a wide age cohort using different meat products. The thesis falls under two parts. Part 1 focused on the food aspect of sensory decline which assessed the impacts of texture modification, fat and salt-reduction, salt-substitution and flavour enhancement; all of which resulted in the development of the most enhanced product that incorporated aging consumer needs. Part 2 focussed on the decline in cognitive and physical ability which occurs as a result of the aging process in order to develop a more suitable, convenient and safe food package for the aging consumer. This thesis offers a design for establishing meal solutions for the elderly consumers based around meat products. Of all product attributes, texture was found to be a major determinant in establishing preferences in various age cohorts. It was found that softer foods which were easier to chew and swallow were favoured by older age cohorts. Flavour differences determined among varying age cohorts was also noted. Preferences for fat, fat-replacers, salt and salt-replacers were established. A consistent decreased perception for salt was noted in study participants aged 41-64 in three studies. The use of trained and consumer panels allowed for the development of the ‘ideal’ processed meat product which was then presented to older consumers in the elderly-friendly packaging formats which were highly accepted. Understanding the needs and requirements of the elderly consumers is paramount in encouraging independent, safe and healthy living of these individuals in our community. It is hoped that this study provides some evidence to educate and assist in this process

Quantifying, Understanding and Predicting Differences Between Planned and Delivered Dose to Organs at Risk in Head & Neck Cancer Patients Undergoing Radical Radiotherapy to Promote Intelligently Targeted Adaptive Radiotherapy

Introduction: Radical radiotherapy (RT) is an effective but toxic treatment for head and neck cancer (HNC). Contemporary radiotherapy techniques sculpt dose to target disease and avoid organs at risk (OARs), but anatomical change during treatment mean that the radiation dose delivered to the patient – delivered dose (DA), is different to that anticipated at planning – planned dose (DP). Modifying the RT plan during treatment – Adaptive Radiotherapy (ART) – could mitigate these risks by reducing dose to OARs. However, clinical data to guide patient selection for, and timing of ART, are for lacking. Methods: 337 patients with HNC were recruited to the Cancer Research UK VoxTox study. Demographic, disease and treatment data were collated, and both DP and DA to organs at risk (OARs) were computed from daily megavoltage CT image guidance scans, using an open-source deformable image registration package (Elastix). Toxicity data were prospectively collected. Relationships between DP, DA and late toxicities were investigated with univariate, and logistic regression normal tissue complication probability (NTCP) modelling approaches. A sub-study of VoxTox recruited 18 patients who had MRI scans before RT fractions 1, 6, 16, and 26. Changes in salivary gland volumes and relative apparent diffusion coefficient (ADC) values were measured and related to toxicity events. Results: Spinal cord dose differences were small, and not predicted by weight loss or shape change. Mean DA to all other OARs was higher than DP; factors predicting higher DA included primary disease site, concomitant therapy, shape change and advanced neck disease. Nine patients (3.7%) saw DA>DP by 2Gy to more than half of the OARs assessed. These patients all had received bilateral neck RT for N-stage 2b oropharyngeal cancer. Strong uni- and multivariate relationships between OAR dose and toxicity were seen. Differences between DA and DP-based dose-toxicity models were minimal, and not statistically significant. On MRI, both parotid and submandibular glands shrank during treatment, whilst relative ADC rose. Relationships with toxicity were inconclusive. Conclusions: Small differences between OAR DP and DA mean that DA-based toxicity prediction models confer negligible additional benefit at the population level. Factors such as primary disease sub-site, concomitant systemic therapy, staging and shape change may help to select the patients that do develop clinically significant dose differences, and would benefit most from ART for toxicity reduction