Fragmentation of a viscoelastic food by human mastication

Fragment-size distributions have been studied experimentally in masticated viscoelastic food (fish sausage).The mastication experiment in seven subjects was examined. We classified the obtained results into two groups, namely, a single lognormal distribution group and a lognormal distribution with exponential tail group. The facts suggest that the individual variability might affect the fragmentation pattern when the food sample has a much more complicated physical property. In particular, the latter result (lognormal distribution with exponential tail) indicates that the fragmentation pattern by human mastication for fish sausage is different from the fragmentation pattern for raw carrot shown in our previous study. The excellent data fitting by the lognormal distribution with exponential tail implies that the fragmentation process has a size-segregation-structure between large and small parts.In order to explain this structure, we propose a mastication model for fish sausage based on stochastic processes.Comment: JPSJ3, 4 pages, 8 figures, minor corrections made for publication in J. Phys. Soc. Jp

Modes of Disintegration of Solid Foods in Simulated Gastric Environment

A model stomach system was used to investigate disintegration of various foods in simulated gastric environment. Food disintegration modes and typical disintegration profiles are summarized in this paper. Mechanisms contributing to the disintegration kinetics of different foods were investigated as related to acidity, temperature, and enzymatic effect on the texture and changes in microstructure. Food disintegration was dominated by either fragmentation or erosion, depending on the physical forces acting on food and the cohesive force within the food matrix. The internal cohesive forces changed during digestion as a result of water penetration and acidic and enzymatic hydrolysis. When erosion was dominant, the disintegration data (weight retention vs. disintegration time) may be expressed with exponential, sigmoidal, and delayed-sigmoidal profiles. The different profiles are the result of competition among the rates of water absorption, texture softening, and erosion. A linear-exponential equation was used to describe the different disintegration curves with good fit. Acidity and temperature of gastric juice showed a synergistic effect on carrot softening, while pepsin was the key factor in disintegrating high-protein foods. A study of the change of carrot microstructure during digestion indicated that degradation of the pectin and cell wall was responsible for texture softening that contributed to the sigmoidal profile of carrot disintegration

Effect of mastication on lipid bioaccessibility of almonds in a randomized human study and its implications for digestion kinetics, metabolizable energy, and postprandial lipemia

Background: The particle size and structure of masticated almonds impact significantly on nutrient release (bioaccessibility) and digestion kinetics. Objectives: To quantify the effects of mastication on the bioaccessibility of intracellular lipid of almond tissue and examine microstructural characteristics of masticated almonds. Design: In a randomized, subject-blind, crossover trial, 17 healthy subjects chewed natural (NA) or roasted almonds (RA) on 4 separate mastication sessions. Particle size distributions (PSDs) of the expectorated boluses were measured using mechanical sieving and laser diffraction (primary outcome). The microstructure of masticated almonds, including the structural integrity of the cell walls (i.e. dietary fiber), was examined using microscopy. Lipid bioaccessibility was predicted using a theoretical model, based on almond particle size and cell dimensions, and then compared to empirically-derived release data. Results: Inter-subject variations (n=15, 2 subjects withdrew) in PSDs of both NA and RA samples were small (e.g. laser diffraction, CV = 12% and 9%, respectively). Significant differences in PSDs were found between these two almond forms (P 500 µm) in masticated almonds. Microstructural examination of the almonds indicated that most intracellular lipid remained undisturbed in intact cells post-mastication. No adverse events were recorded. Conclusions: Following mastication, most of the almond cells remained intact with lipid encapsulated by cell walls. Thus, most of the lipid (>88%) in masticated almonds is not immediately bioaccessible and remains unavailable for digestion and absorption. The lipid encapsulation mechanism provides a convincing explanation for why almonds have a low metabolizable energy content and an attenuated impact on postprandial lipemia. Trial registration number; ISRCTN58438021

Understanding the relevance of in-mouth food processing. A review of in vitro techniques

[EN] Oral processing of food is the first step in the eating process. Although the food undergoes a number of changes during mastication that influence the subsequent steps, this stage has very often been neglected in studies of digestion, bioavailability, flavor release, satiety potential, glycemic index determination, etc. The present review draws on different sources such as nutrition, medicine, phoniatry and dentistry to explain some in vitro oral processing methods and techniques that could be transferred to food technology studies to mimic in vivo comminution, insalivation, and bolus formation, describing, as a necessary reference, the respective in vivo physiological processes they attempt to imitate. Developing a deeper understanding of all the aspects of in-mouth process will help food technologists to give this crucial step the necessary attention its due importance and to consider better ways to incorporate it into their studies.The authors wish to acknowledge the financial support of the Spanish Government (project AGL2012-36753-C02) and gratefully acknowledge the financial support of EU FEDER funds. Mary Georgina Hardinge assisted with the translation and corrected the English text.Morell Esteve, P.; Hernando Hernando, MI.; Fiszman, SM. (2014). Understanding the relevance of in-mouth food processing. A review of in vitro techniques. Trends in Food Science and Technology. 35(1):18-31. https://doi.org/10.1016/j.tifs.2013.10.005S183135

Les Tests diagnostiques en parodontie (intérêts cliniques)

CLERMONT FD-BCIU-Santé (631132104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Particle size distribution in the food bolus after mastication of natural foods

International audienceThe main goal of mastication is to prepare a food bolus suitable for deglutition. The bolus preparation consists in food breakdown and processing during which oral sensations are generated. This study was performed to examine the particle size distribution in the bolus formed by chewing 10 natural foods. Ten young subjects with normal dentition were asked to chew the food and to expectorate the bolus just before swallowing, while masticatory parameters were recorded. The particle size distribution of each bolus was evaluated by wet sieving. The number of cycles, sequence duration and masticatory frequency varied among subjects and foods. The particle size distributions differed among foods but were similar among subjects. The median particle size d(50) gave a range from 0.82 to 3.04 mm allowing a food classification based on the state of the bolus. The d(50) value reflected the fracturability and may be useful to describe food behaviour in the mouth during bolus preparation

Apport des mini-implants dans le traitement de l’édentement total mandibulaire

Grâce au progrès de la prévention, l’édentement total est souvent synonyme de grand âge. Le vieillissement diminue les capacités d’adaptation et dégrade les conditions cliniques. Par le passé les seules solutions pour surmonter ces difficultés impliquaient l’usage d’adhésif prothétique ou la conservation de racines sous-prothétiques. Actuellement, la prothèse adjointe complète sur implant (PACSI) est considérée comme le standard dans le domaine de la prothèse adjointe complète mandibulaire. En effet, la région symphysaire tolère généralement la mise en place d’implants même en cas de mandibules fortement résorbées. Cependant, chez les personnes très âgées ou fragilisées par des pathologies handicapantes, l’utilisation d’implants standards dans le traitement de l’édentement total se heurte à la lourdeur du protocole et des suites chirurgicales. Dans ce contexte, l’utilisation de mini-implants offre une alternative intéressante. Ce travail dresse un premier bilan de l’utilisation, dans le service d’odontologie du CHU de Clermont-Ferrand, des mini-implants OBI®, produit par Euroteknika. L’objectif est de stabiliser une PTA mandibulaires chez des patients âgées par mise en charge immédiate de quatre mini-implants. Au cours de cette évaluation pilote, les critères d’ostéointégration des implants et l’amélioration du confort oral des patients seront particulièrement pris en compte