The Importance of Food Perception in Food Choices and Nutrition

Nowadays, there is a growing interest in understanding and modulating consumer choices, both for healthy and economic reasons. However, food preferences are influenced by a diversity of factors, which interact among them to a final behaviour. The understanding of food choices is linked with the comprehension of how consumers perceive food and how the different levels of perception (sensorial, psychological, socio-economic) affect those choices. Traditionally, the effect of each discipline was studied independently. Nowadays, the complexity inherent to the decision process is recognized and multidisciplinary studies, where the different dimensions of choices are considered, are increasing. Motivation for consumption is greatly affected by the way individuals identify food. This recognition should be considered at different levels: sensorial, emotional, social and physiological. As such, variability in food characteristics, including food constituents and technological processing, as well as variations in individuals’ characteristics, such as believes, experiences and physiology, and variations in the context in which food is experienced, can greatly affect the final perception.FC

Salivary proteomics as a tool to understand ingestive behavior: an experimental study in sheep (Ovis aries), goat (Capra hircus) and mice (Mus musculus)

The oral cavity is the part of the animal internal medium that first comes into contact with food. Numerous chemical and mechanical receptors in the mouth respond to the food chemical and physical properties and monitor the changes during processing. This leads; to central perception of taste and texture of food, which, together with odor, are important determinants in the decision of to ingest or not. Saliva plays an important role in the perception of taste and texture sensations. Its composition can modulate food perception and, simultaneously, be modulated by the type of diet. This thesis is focused on the study of the role of salivary proteins on ingestive behavior. Tannins are used as a modal to access changes in salivary protein profile induced by dietary compounds. These plant secondary metabolites produce aversive taste/oral sensations influencing animal diet choices. The levels of dietary tannins tolerated vary according to the physiological mechanisms that animals possess to avoid their potential negative effects. Saliva, and more particularly salivary proteins, has been pointed as a defense mechanism against tannins. Three animal species were studied: sheep, goat and mice. The first two species are ruminant species and present similar digestive characteristics, but differ between them in the levels of dietary tannins tolerated. Mice, on the other hand, represent a rodent mammalian specie with different digestive characteristics. We have studied the effect of tannins on mice salivary gland histomorphology (chapter 2) since these are the sites of salivary protein production. Both condensed and hydrolysable tannins produced major effects in the acinar structures, with condensed tannins having a stronger effect. The similarities between these effects and the ones produced by isoproterenol suggested that tannins act through activation of sympathetic nervous system. The effects of quebracho tannin and tannic acid on mice whole saliva protein composition were studied by comparing the SDS-PAGE profile of control animals to the ones from animas fed with these compounds during 10 days (chapter 3). Matrix Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry (MS) data were used to identify salivary proteins. One isoform of salivary amylase was observed to increase in response to both types of tannins. Despite a considerable number of studies on mice salivary glands and saliva, a proteome of mice whole saliva was not, at our knowledge, characterized to date. In chapter 4 we used two-dimensional electrophoresis coupled to MALDI-TOF MS for this purpose. A total of 26 proteins were identified. The effects of the ingestion of quebracho tannin for a period of ten days were studied in the salivary protein fraction, which does not precipitate tannins. The expression leveis of one isoform of alpha amylase and of an unidentified protein were observed to increase, whereas acidic mammalian chitinase and Muc10 decreased. Additionally, two protein spots were induced, that were not identified by MS, but, based on their staining characteristics, we suggest them to be proline-rich proteins, Sheep and goat parotid saliva proteomes were characterized and compared, and total of 40 parotid salivary proteins were identified, with differences between the two species being reported (chapters 5 and 6). , Two-dimensional electrophoretic protein saliva maps of animals in control diets and after 10 days quebracho tannin consumption were compared (chapter 6). Changes in salivary protein expression levels induced by tannins were observed, some of which are common to sheep and goats and others specific of each species. Altogether the results suggest that salivary proteome study can be important in understanding feeding behavior and that proteome is influenced in the short-medium terra by diet composition. Although differences among mice, sheep and goats exist, in response to tannin ingestion, a common feature to the three species is the increase in the expression levels of proteins usually increased in stress situations. This, together with the histomorphometric data, which point to an action of tannins in sympathetic nervous system, suggests that the mechanisms involved in salivary protein regulation by tannins may be related to a "stress response" imposed by these compounds. /RESUMO - A cavidade oral é o local de primeiro contacto entre o alimento e o ambiente interno do animal. Numerosos receptores químicos e mecânicos, presentes na boca, respondem às propriedades químicas e físicas dos alimentos e monitorizam as alterações durante o seu processamento. Isto tem como consequência a percepção do gosto e textura dos alimentos, os quais em conjunto com o olfacto, são determinantes na decisão de ingerir. A saliva desempenha um papel de extrema importância neste processo, pois a sua composição pode modular a percepção dos alimentos, e, em simultâneo, ser modulada pelo tipo de dieta. A presente tese tem como objectivo o estudo do papel das proteínas salivares no comportamento ingestivo. Para avaliar as alterações na secreção de proteínas salivares induzidas por compostos presentes na dieta utilizaram-se três tipos de taninos: ácido tânico, chestnut (taninos hidrolisáveis) e quebracho (taninos condensados). Estes metabolitos secundários das plantas produzem sensações gustativas/orais aversivas que influenciam a escolha da dieta, por parte dos animais. Os níveis de taninos, presentes na dieta, tolerados pelas diferentes espécies animais variam de acordo com os mecanismos fisiológicos que cada u ma possui para evitar potenciais efeitos negativos. A saliva, e mais especificamente as proteínas salivares, têm sido apontadas como componentes de mecanismos de defesa que contrariam os efeitos dos taninos. Para avaliar a importância da saliva no comportamento ingestivo, e mais especificamente no consumo desses compostos, foram estudadas três espécies: ovelhas (Ovis arfes), cabras (Capra hircus) e murganhos (Mus musculus). As duas primeiras apresentam características digestivas semelhantes, mas diferem entre elas nos níveis de taninos que toleram; os murganhos, por outro lado, representam uma espécie de mamíferos com diferentes características digestivas. No capitulo 2 estudaram-se os efeitos dos taninos ao nível da histomorfologia das glândulas salivares de murganhos. É conhecido que, em roedores de laboratório, proteínas salivares, como as proteínas ricas em prolina (PRPs), são induzidas por agonistas do sistema nervoso simpático (ex. isoproterenol), e que essa indução está inter-relacionada com um aumento do tamanho das estruturas atinares das glândulas parótidas e submandibulares. 0 efeito do consumo de taninos apresenta semelhanças com o efeito provocado pelo tratamento com isoproterenol, no que diz respeito a um aumento da massa glandular e à indução de PRPs. De modo a estudar os efeitos dos taninos, a nível da histomorfologia das glândulas salivares, murganhos foram submetidos a dietas com três taninos pertencentes a diferentes classes estruturais (ácido tânico, chestnut e quebracho), ou injectados com isoproterenol, durante dez dias. 0 tamanho dos ácinos das glândulas salivares, parótidas e submandibulares, aumentou significativamente, tendo sido esse aumento maior para as glândulas parótidas, comparativamente às glândulas submandibulares, e maior para os animais que consumiram quebracho, comparativamente com os outros tipos de taninos. 0 tratamento com qualquer um dos três tipos de taninos também resultou num aumento significativo do tamanho dos ácinos das gandulas sublinguais, ao contrário do tratamento com isoproterenol, que não produziu alterações significativas nestas estruturas. Os resultados obtidos por nós estão de acordo com outros estudos que sugerem que os taninos actuam a nível do sistema nervoso simpático, mais concretamente ao nível dos receptores beta-adrenérgicos. No entanto, e devido à observação de efeitos produzidos ao nível das glândulas sublinguais, não são de excluir mecanismos adicionais da acção dos taninos. Para além disso, são apresentadas evidências de que os efeitos produzidos pelos taninos dependem da estrutura destes compostos, e é possível que os murganhos necessitem de produzir uma maior quantidade de proteínas salivares, como defesa contra a acção de taninos condensados, comparativamente a taninos hidrolisáveis. Presentemente sabe-se que, dois grupos de proteínas salivares, histatinas e proteínas ricas em prolina, apresentam uma elevada afinidade para taninos, diminuindo a actividade biológica destes compostos. A possibilidade de existirem outras proteínas salivares com funções de defesa contra taninos é desconhecida. No capítulo 3 caracterizaram-se e compararam-se os perfis proteicos da saliva mista de murganhos submetidos a três tipos de dieta: controlo, com a incorporação de taninos hidrolisáveis (5% ácido tânico) ou coma incorporação de taninos condensados (5% quebracho). As proteínas foram separadas de acordo com as suas massas moleculares, por electroforese em gel de poliacrilamida Sodium Dodecyl Sulphate-Polyacrylamide Gel Electroforesis (SDS-PAGE), e analisadas utilizado um espectrómetro de massa com ionização do tipo MALDI (Matriz Assisted Laser Desorption/Ionization) associado a um analisador de massas, do tipo "tempo de voo", TOF (Time of Flight). A identificação das proteínas presentes nas bandas isoladas foi feita através do método "Peptide Mass Fingerprinting" (PMF). Uma vez que as proteínas mais abundantes dificultam a observação e identificação de proteínas com menores níveis de expressão, recorreu-se à centrifugação para remoção das proteínas precipitadas pelos taninos. Foi possível identificar dez proteínas salivares diferentes, algumas das quais apresentando diferentes isoformas. A adição de taninos à dieta provocou alterações no perfil proteico da saliva. Uma isoforma de alfa-amilase foi sobre-expressa em consequência do consumo de ambos os tipos de taninos. Por outro lado, a proteína aldeído redutase foi identificada apenas no grupo que consumiu quebracho. Apesar do número considerável de estudos realizados com glândulas salivares e saliva de roedores de laboratório, a caracterização do proteoma da saliva destas espécies não se encontra ainda descrita. No capítulo 4 pretendeu-se caracterizar o proteoma da saliva mista de murganho, recorrendo à separação proteica por electroforese bi-dimensional, seguida da identificação das proteínas por PMF, e avaliação das alterações provocadas pelo consumo de taninos na composição proteica da saliva que não é precipitada por esses compostos

Changes in mouse whole saliva soluble proteome induced by tannin-enriched diet

<p>Abstract</p> <p>Background</p> <p>Previous studies suggested that dietary tannin ingestion may induce changes in mouse salivary proteins in addition to the primarily studied proline-rich proteins (PRPs). The aim of the present study was to determine the protein expression changes induced by condensed tannin intake on the fraction of mouse whole salivary proteins that are unable to form insoluble tannin-protein complexes. Two-dimensional polyacrylamide gel electrophoresis protein separation was used, followed by protein identification by mass spectrometry.</p> <p>Results</p> <p>Fifty-seven protein spots were excised from control group gels, and 21 different proteins were identified. With tannin consumption, the expression levels of one α-amylase isoform and one unidentified protein increased, whereas acidic mammalian chitinase and Muc10 decreased. Additionally, two basic spots that stained pink with Coomassie Brilliant Blue R-250 were newly observed, suggesting that some induced PRPs may remain uncomplexed or form soluble complexes with tannins.</p> <p>Conclusion</p> <p>This proteomic analysis provides evidence that other salivary proteins, in addition to tannin-precipitating proteins, are affected by tannin ingestion. Changes in the expression levels of the acidic mammalian chitinase precursor and in one of the 14 salivary α-amylase isoforms underscores the need to further investigate their role in tannin ingestion.</p

European dog owner perceptions of obesity and factors associated with human and canine obesity

Obesity is a common nutrition-related disorder leading to reduced life expectancy in both humans and dogs. With the aim of identifying new prevention and control options, the study objectives were (1) to investigate dog-owner perceptions about obesity in terms of themselves and their dogs, and (2) to identify factors associated with obesity and possible social, environmental and economic drivers for its development in dog owners and their pets. A cross-sectional questionnaire-based study was performed across multiple countries. The questionnaire focused on human and canine obesity, associated factors and potential drivers, and was distributed online and in the form of hard copies among dog owners in 11 European countries. In total, 3,185 responses from ten countries were included in multivariable analyses. Between 19.1% and 48.8% of the dog owners reported to be overweight/obese. Owner-reported overweight/obesity in dogs ranged from 6.0% to 31.3% based on body condition score charts, and 31.8% to 69.4% based on body fat index charts. Common factors associated with obesity in owners and their dogs were age, gender and owners’ attitudes to diet and physical activity. Dog owners who did not consider obesity to be a disease were more likely to have obese dogs

Sweet music influences sensory and hedonic perception of food products with varying sugar levels

Reducing sugar intake is an important nutritional goal in most developed countries. Despite the health consequences of excessive sugar consumption (e.g., non-communicable diseases), individuals are often reluctant to shift dietary habits due to the high hedonic appeal of sugar-rich products. Manipulating the intrinsic sensory attributes of foods (such as color or aroma) has been put forward as a promising framework for enhancing taste perception and increasing acceptance of low-sugar products. So far, it is less known whether extrinsic sensory cues may have similar effects. In this within-subjects experiment (N = 106, 64 % women), we tested how auditory stimuli (i.e., music) may impact the perception and acceptance of products varying in sweetness levels. Participants tasted samples of two product categories (vegetables and cookies), with higher (carrots and cookies) and lower sweetness levels (cucumbers and 0 % sugar cookies), while listening to previously tested soundtracks that were strongly (vs weakly) associated with sweetness. Results showed that the high “sweetness” soundtrack increased the sweetness ratings of all products compared to the low “sweetness” soundtrack. Participants also reported higher preference and more favorable intentions of future consumption when the high “sweetness” soundtrack was played. Overall, these findings suggest that extrinsic sensory cues, namely music, may aid in reducing sugar intake by increasing the acceptance of products with lower sugar content

The Role of Saliva in Food Sensory Perception: Relevant Knowledge to Design Healthy Foods

Food choices and consumption are determined by a range of factors that contribute to aversion or pleasure and guide to final intake. Among these, the sensorial characteristics of food have a major and decisive role in choice behaviour. Although some of the mechanisms involved in oral food perception, namely in taste and astringency perception, are considerable known, many questions remains, particularly in what concerns variations among individuals in their sensitivity for food sensorial aspects. The understanding of the mechanisms leading to different responses for the same sensorial stimulus is particularly important to understand food choices. Bitter has been the basic taste most studied for variations among individuals in perception and in how this influences food behaviour and nutritional status. The observation, at several years ago, that some individuals are very sensitive to the bitterness of the compounds phenyl thiocarbamide (PTC) or 6-n-propylthyouracil (PROP), whereas others are almost insensitive, triggered the emergence of diverse studies about the motif for that, resulting in the identification of gene polymorphisms for the bitter taste receptor TAS2R38. Subsequently to that, polymorphisms for other receptors and taste qualities have been identified. Even so, these genetic variations are not able to explain the total diversity in taste/oral sensations responses. In recent years, it has begun to become apparent that saliva has a relevant role in taste recognition mechanisms. Apart from astringency, which is well known to depend on salivary proteins to develop and being perceived, basic tastes started to be related with saliva composition. Some salivary proteins, among which carbonic anhydrase VI, cystatins, amylase and others, have been observed to relate with taste perception. However, saliva secretion changes with taste stimulation and according dietary habits. Moreover, body weight condition, metabolic status or diverse pathologies are responsible for changes in saliva composition. Being this fluid important in modulating oral food perception, to know individuals’ saliva composition becomes of interest for modulating or directing choices. Based on the literature and recent scientific results, the role of saliva in food sensory perception will be discussed according to these two angles. The question of the high between-subject variability in view of saliva properties and its consequence on perception will be emphasized.Acknowledgements This article was funded by FCT-Science and Technology Foundation as part of Project UID/AGR/00115/2013. Funding was additionally provided by the FCT-Portuguese Science Foundation: research contract IF/01778/2013-Elsa Lamy, while FCT was not involved in carrying out this study or submitting it for publication

Alterações na actividade enzimática da amílase salivar em indivíduos obesos

Nos últimos anos o estudo da composição proteica da saliva ganhou interesse pelo seu potencial no diagnóstico não invasivo e compreensão de diversas doenças, quer orais, quer sistémicas. Para além disso, a interacção deste fluido com os constituintes dos alimentos tornam a sua análise importante para a compreensão das variações a nível da percepção dos alimentos e escolhas alimentares. Há, contudo, poucos estudos que comparem a composição proteica da saliva de indivíduos obesos com indivíduos normoponderais. Uma das proteínas mais abundante na saliva é a α-amilase. Esta proteína é responsável pelo início da digestão de hidratos de carbono na boca influenciando a percepção dos alimentos. Para além disso, os seus níveis são indicadores do funcionamento das glândulas salivares, tendo ainda sido sugerida como potencial marcador de condições de stress e de actividade do sistema nervoso simpático. O presente trabalho teve como objectivo comparar os níveis de α-amilase salivar entre indivíduos obesos (IMC>30; N=10) e normoponderais (IMC<25; N=10) do sexo feminino. Foram feitas recolhas de saliva mista, na ausência de estimulação e sempre à mesma hora do dia. Para determinar a actividade enzimática da α-amilase utilizou-se um kit colorimétrico (Sentinel Diagnostics). Foi observada uma maior actividade enzimática de α-amilase nos indivíduos obesos comparativamente aos normoponderais (243,2 X 103 ± 37,7 X 103 e 106,1 X 103 ± 44,2 X 103 U/L, respectivamente) A maior actividade enzimática da α-amilase poderá contribuir para alterações na percepção dos alimentos, nomeadamente no que diz respeito ao gosto doce dos hidratos de carbono. Uma diferente sensibilidade gustativa poderá ter influências nas escolhas alimentares. Estes resultados reforçam a importância de estudos mais aprofundados acerca da função salivar e percepção gustativa na obesidade

A Master’s Degree research: Proteomic approach on ewe’s cheese.

A MASTER’S DEGREE RESEARCH: PROTEOMIC APPROACH ON EWE’S CHEESE Ana Lúcia Garrido1, Flávio Silva1, Cristina Conceição1,2, Sofia Freitas1 Elsa Lamy2 1Departamento de Zootecnia, Universidade de Évora, Portugal; 2ICAAM, Universidade de Évora, Portugal; ABSTRACT A master’s programme structure is usually flexible and involves a comparably dissertation that is based on a research or a practice-led research project. It involves a scientific exploration that helps students obtaining investigation skills and acquiring some transversal competences. The main challenge of this academic process is to build an idea, identify the problematic, organize the hypothesis and stablishing the best methodology to get answers according to the objectives. This master’s degree research was developed within a multidisciplinary project, and the main objective was to investigate which proteomic methodology was better to investigate the degradation of cheese nitrogen fractions, with the resources available at University of Évora. Ewe’s cheeses have great tradition in Portugal, and have a high intrinsic value, arising from their very appreciated unique sensory characteristics, coupled with long-recognized social and economic impacts. Therefore, it’s mandatory to understand the metabolic pathways in cheese ripening, and specifically, proteolysis. Three electrophoretic techniques have been used: urea polyacrylamide gel electrophoresis (Urea-PAGE) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) for the insoluble fraction of cheese and two-dimensional gel electrophoresis (2-DE) for the soluble fraction. Results showed that urea-PAGE was the best method for cheese insoluble fraction analysis, mainly because it separates proteins not only by molecular mass, but also having charge into account, and since caseins have similar molecular masses SDS-PAGE is not able to separate them (1–3). This research investigation also concluded that both urea-PAGE and 2-DE methods are complementary in the study of proteolysis of ewe’s cheese. Urea-PAGE results showed a degradation of the insoluble fraction, the caseins, during maturation, and the 2-DE showed an increase of the soluble fraction, that according to other results (3) we believe that are peptides resulting from the degradation of caseins. Keywords: ewe’s cheese; proteolysis; electrophoresis; caseins

Distribution and expression of leptin in major salivary glands of a hyperleptinemia animal model

Saliva production is mainly regulated by the autonomic nervous system (sympathetic and parasympathetic); however studies indicate a possible hormonal influence on the control of salivary secretion. This study aims to assess if the induction of increased levels of circulating leptin influence the immunohistochemical expression of leptin at the level of major salivary glands in Wistar rats. It was found that the expression, in qualitative terms, of leptin has been positive, being more evident in submandibular and sublingual glands, either in the acini or ducts. However, through this technique, no obvious differences between groups could be observed. The results suggest that circulating leptin levels may not affect the expression of this hormone in the major salivary glands

Editorial: Food Oral Processing and Nutrition Through the Lifespan

A balanced healthy diet is recognized as essential to prevent several non-communicable diseases, such as diabetes, hypertension, cardiovascular diseases or even some types of cancer. The need to promote shifts to healthier diets is even more relevant in the actual context, where obesity rates are increasing worldwide. Effective nutritional strategies, aimed at promoting healthier eating habits are warranted, from young to old ages. But for this purpose, a good comprehension of the factors involved in food preferences and choices is required. Food oral processing comprises the sequence of transformations that food undergoes inside the mouth and will influence food sensory perception and food digestion. In oral processing, the food structure is first deformed and degraded by the forces applied by the teeth and soft tissues, including the tongue. Following, the fragments formed upon chewing are mixed with saliva, producing a bolus that can be safely swallowed. During this dynamic and synchronized process, the continuous interactions between oral structures, saliva and food produce the multiple sensations that are processed by humans into sensory perception. Moreover, the way the different food structures are broken and the food pieces are mixed with saliva affects (favoring or limiting) the biological availability and absorption of nutrients