Food Particle Size Research Articles

Effects of food bar chewing duration on the physiologic, metabolic, and perceptual responses to moderate-intensity running

PurposeChewing duration can affect food particle size, gastric processing, and postprandial glycemia, but these effects have not been investigated with exercise. This study examined how the chewing duration of a food bar impacts glycemic and metabolic responses, gastrointestinal (GI) symptoms, psychological affect, and performance during endurance running.MethodsThis randomized, unblinded, crossover study had 15 males (35.2 ± 7.4 years, VO2peak: 56.1 ± 5.2 ml/kg/min) attend three laboratory visits. Visit 1 required a VO2peak test, 10 min familiarization run at 60% VO2peak, and familiarization time-to-exhaustion (TTE) test (10 min at 90% VO2peak, followed by TTE at 100% VO2peak). Visits 2 and 3 consisted of a 60 min run at 60% VO2peak, followed by TTE testing. Participants were fed 45 g of a bar (180 kcal, 4 g fat, 33 g carbohydrate, 3 g protein, 1 g fiber) in 9 g servings 30 min before running, and 27 g of bar in 9 g servings at three timepoints during the 60 min run. Participants consumed the servings in 20 (20CHEW) or 40 (40CHEW) masticatory cycles, at 1 chew/second. Outcomes included blood glucose, substrate use, GI symptoms, perceived exertion (RPE), overall feeling, and TTE.ResultsPost-prandial blood glucose, GI symptoms, and RPE increased over time, but there were no significant between-condition or condition-by-time effects. TTE showed no significant between-condition effect (20CHEW: 288 ± 133 s; 40CHEW: 335 ± 299 s; p = 0.240). Overall feeling demonstrated a time-by-condition effect (p = 0.006), suggesting possible better maintenance over time with 40CHEW.ConclusionCumulatively, the results suggest that extended chewing minimally impacts physiology, perceptions, and performance during 60 min moderate-intensity running.

Interplay between particle size and microbial ecology in the gut microbiome.

Physical particles can serve as critical abiotic factors that structure the ecology of microbial communities. For non-human vertebrate gut microbiomes, fecal particle size (FPS) has been known to be shaped by chewing efficiency and diet. However, little is known about what drives FPS in the human gut. Here, we analyzed FPS by laser diffraction across a total of 76 individuals and found FPS to be strongly individualized. Contrary to our initial hypothesis, a behavioral intervention with 41 volunteers designed to increase chewing efficiency did not impact FPS. Dietary patterns could also not be associated with FPS. Instead, we found evidence that human and mouse gut microbiomes shaped FPS. Fecal samples from germ-free and antibiotic-treated mice exhibited increased FPS relative to colonized mice. In humans, markers of longer transit time were correlated with smaller FPS. Gut microbiota diversity and composition were also associated with FPS. Finally, ex vivo culture experiments using human fecal microbiota from distinct donors showed that differences in microbiota community composition can drive variation in particle size. Together, our results support an ecological model in which the human gut microbiome plays a key role in reducing the size of food particles during digestion. This finding has important implications for our understanding of energy extraction and subsequent uptake in gastrointestinal tract. FPS may therefore be viewed as an informative functional readout, providing new insights into the metabolic state of the gut microbiome.

Bioavailability and health effects of some carotenoids by different cooking methods

Humans lack the inherent capability to synthesize carotenoids, necessitating their acquisition through dietary sources or supplementation. Among the carotenoids prevalent in our daily nutritional intake are beta-carotene, lycopene, lutein, beta-cryptoxanthin, alpha-carotene, and zeaxanthin. They have antioxidant features thanks to their ability to capture ROS (reactive oxygen species) and free radicals. Particularly beta-carotene, lycopene and lutein are carotenoids with high antioxidant capacity. However, with the effects of factors, such as oxygen, high temperature, light exposure, and pH, they are oxidatively degraded and their bioavailability in the body changes. Among food processing methods, reducing food size and dietary fiber inhibits the absorption of carotenoids by micellization and inactivating pancreatic lipase, while monounsaturated fatty acids have been shown to increase bioavailability and absorption. In vitro studies on various vegetables and fruits with the effect of exogenous factors showed that the addition of oil, increase in lycopene processing, decrease in food particle size, increase in micellization with the breakdown of dietary fibers, and increase in bioavailability as a result of the destruction of cell walls with heat treatment. The addition of olive oil with heat treatment and the factors of decreasing food particle size have positive effects on health by transforming carotenoids into forms with high bioavailability in the body. This review endeavors to investigate the bioavailability of select carotenoids, namely lycopene, beta-carotene, and lutein, in light of various cooking methods and processes, as well as to elucidate their implications for health resulting from heat treatments.

Niche differentiation among facultative filter feeders: Insights from invasive Ponto-Caspian mysids.

The degree of dietary specialization has a fundamental impact on the ecological function and interactions of suspension feeders. While niche differentiation by food particle size is common among obligate suspension feeders, its role is not evident in facultative ones. In this study, we aimed at providing new insights on the matter by focusing on sympatric mysid species. As mysids use different mechanisms for raptorial and filter-feeding, they represent a more adequate model system than for example, the more extensively studied copepods. We made morphological measurements on the 4 coexisting invasive Ponto-Caspian mysid species to determine the areas and mesh sizes of their filters. We also quantified their clearance rates on the microalga Cryptomonas sp. in a laboratory experiment to reveal how morphological differences manifest in their overall filtering capacity. We found relatively small but consistent differences in the primary filter area among the species, indicating that morphological constraints due to the enclosed position of the setae might limit the possibility for differentiation. The primary filter mesh sizes were small in all 4 species (0.69-2.73 μm) with moderate but consistent intraspecific differences, suggesting that the benefit of being able to capture small particles might outweigh the pressure for differentiation. The observed clearance rates were in accordance with the morphological characteristics of the species, highlighting that auxiliary filters (present in one of the species, Limnomysis benedeni) are needed to increase filtering capacity considerably. Our study confirmed that food particle size can contribute to the niche differentiation of facultative filter feeders, but also indicated that they can tolerate a higher overlap than obligate ones. The observed differences were related to the habitat preferences and predatory potentials of the species, suggesting that complementarity among the different niche axes might further facilitate their coexistence.

Urbanization causes shifts in the functional traits and foraging activity, and alters food particle size preference and biomass removal of urban-dwelling ants

Urbanization may lead to changes in assemblage and result in shifts in trait distribution from natural habitats to highly urbanized habitats. The shift in functional traits can affect ecosystem functions in urban areas. This study explored the foraging period of ants over 72 h and determined the relationship between the behavioral, morphological, and physiological traits of local foragers ants and environmental conditions in urban and forest sites. In addition, this study examined the ants’ ecosystem functions and compared it with that of their forest counterparts. Our results revealed that the foraging period of ants (i.e., Cardiocondyla sp.1, Monomorium chinense, Paratrechina longicornis, Pheidole megacephala, and Solenopsis sp.1) in urban areas peaked between 0900 and 1500 and that of some ants (i.e., Carebara diversa, P. megacephala, Pheidole fervens, Plagiolepis longwang, and Nylanderia sp.1) in forest areas was constant over time. For urban ants, a weak correlation was observed between foraging period and body size traits (i.e., Weber’s length and head width). This finding indicates that the major factor underlying the change in the foraging period might not be related to body size. Rather, the change may be attributed to synchronization between food availability and human activity (waste disposal; i.e., between 0900 and 1800). The shift in the functional traits of ants affects ecosystem functions in urban areas. In urban areas, although only one predatory ant species (P. megacephala) was sampled, its activity density was high. Most of these individuals were active during the daytime, indicating that the predatory behavior of ants in the novel urban environment has decreased temporally and is limited to the daytime. Urban ants tended to choose smaller food particles, whereas forest ants preferred larger food particles and had a twofold higher food removal rate.

Dynamical Numerical Model of the Molluscan Radula in its Interaction with the Substrate and Food Particles

AbstractThe radula, a chitinous membrane with teeth, is the molluscan autapomorphy for food gathering and processing. Even though this structure is studied for decades, the interplay between the structure and the particular food or/and the substrate remains mostly enigmatic. Here, we provide a numerical model approach to understand the relationship between structure, feeding efficiency, and partial work performed by the system. This first simple dynamic numerical radular model interacts with the food particles and the uneven substrate. This protocol can be applied to any system in the future, as the parameters (interaction between structures, adhesion, size of food particles, attachment angle of teeth to membrane, etc.) can be easily altered. This will shed light on the biomechanical adaptations of this feeding structure (e.g., wear and failure prevention) to the specific environment.

103 Chew frequency and duration in horses consuming bermudagrass hay in slow feeders as compared to loose hay

Stabled horses are predisposed to gastrointestinal disorders related to hay consumption. Horses produce saliva when chewing which contains sodium bicarbonate to buffer stomach acid, lubricate a food bolus, and aid in digestion. Chewing hay over a prolonged period allows for buffering of stomach acid to aid in prevention of gastric ulcers. Additionally, increased chewing results in food particle size reduction and improves lubrication to potentially decrease the incidence of impaction colic. Hay nets have been promoted to slow the rate of hay consumption, with many styles of nets and slow feeders currently marketed for horses. No research has yet demonstrated whether hay nets cause the horse to increase their chewing frequency and chewing duration, or whether the slowing effect is simply due to restriction in the amount of forage they can ingest per bite. The objective of this study was to compare chew frequency (CF, total number of chews/kg consumed) and chew duration (CD, total minutes chewed/kg consumed) of horses eating bermudagrass hay in 3 styles of hay nets [large mesh (LM), small mesh (SM), bottom hole (BH)] as compared with a control of loose hay (CTL). Before initiating this project, trial data was collected from 2 horses over 4 d and demonstrated that horses acclimate quickly to hay nets. No differences were seen in CF from day one through d 4 (P = 0.49). Eight horses were then divided into 2 trials, with the4 horses in each trial rotating through treatments in a Latin square design.Each horse was given a 24-h acclimation period to a treatment, and then their chewing patterns were recorded for the following 24 h using an automated halter fit with a pressure-sensor noseband (EquiwatchTM, Liestal, Switzerland). Refused hay was weighed back, and CF and CD were calculated per kg of hay consumed. Data were analyzed using Minitab v.21 (State College, PA, USA) as a mixed model ANOVA with net type as the fixed effect and a post hoc Tukey's test to compare treatments. Data with P < 0.05 were considered statistically different. No treatment difference was noted in amount of hay consumed, with horses chewing an average of 6.8 ± 0.3 kg per treatment. Results indicate no difference between treatments in CF (P = 0.72). CD showed no overall treatment effect (P = 0.27), however, when individual treatments were compared, a statistical difference between SM and CTL was noted (262 vs 189 min respectively, P = 0.001). Results of this study indicate that slow feeders do not influence the number of chews a horse performs while masticating hay, but small mesh feeders do increase the amount of time spent chewing as compared with loose hay.

In vitro digestion and fermentation of Japanese macaque (Macaca fuscata) food: The influence of food type and particle size.

Chewing is critical for herbivores to obtain nutrients. Measuring digesta particle size as the outcome of chewing can improve our understanding of the relationship between food and digestion. Previous studies of feeds of domestic animals have shown that smaller digesta particle size leads to more efficient digestion. Increased digesta particle size-either due to animal factors (e.g., a senile dentition) or to feed factors (e.g., fracture resistance) could be a sign of an animal experiencing compromised nutritional intake. However, for some primates that are dietary generalists, digesta particle size has been shown to increase when consuming preferred foods, which raises doubts about the role of chewing in digesting such foods. This uncertainty makes it difficult to understand the connection between diet, chewing, and digestion through digesta particle size in dietary generalists. In this study, using five typical food items from the Japanese macaque (Macaca fuscata) diet, we conducted in vitro digestibility and fermentation assays to explore the effects of particle size on enzymatic and microbial digestion. For the fermentation assays, we used feces from captive Japanese macaques as inoculum. Among the five food items, we found that particle size has a stronger influence on the digestibility of seeds and mature leaves compared to young leaves and pulp. The influence of particle size on the fermentation rate was stronger in pulp and seeds compared to that in leaves. The differences in physical structure, texture, digestion barriers, and soluble components may play important roles in such differences. These results support the hypothesis that reducing food particle size is less important for consuming fruits than for consuming leaves. The limited effects of particle size on digesting fruits suggest that the two fruits examined in this study are cost-effective concerning food processing and chewing.

Digestion of meat proteins in a human-stomach: A CFD simulation study

Understanding gastric digestion mechanisms is important for the design of functional foods. In this study, we have investigated the meat-protein digestion in human-stomach by using a CFD method. The gastric motility is modeled with a dynamic mesh. The disintegration of large food particles in an acidic environment is simulated using a reaction-diffusion-convection model. A food matrix is used to model the large food-particles. The numerical results show that the digestion and emptying become faster when the meat is treated at a higher temperature. The digestion rate is reduced considerably when the gastric motility or the H+ secretion is weakened due to a stomach disorder. TACs stimulate backflows which enhance the transport of enzymes and H+, thereby accelerating the digestion process. Due to the flow resistance by the food matrix made of large food particles, liquid gastric contents are emptied in a pathway close to the stomach inner-surface. Large food-particles are mainly disintegrated in the region next to the stomach inner-surface. Therefore, the characteristic length scale of species transport (for enzymes or H+) should be the size of food matrix, instead of the size of large food-particles.

Tiempo necesario para que las bacterias ruminales se adapten a los cambios en la dieta del ganado confinado: Revisión

The system of production in animals’ feedlot is an excellent strategy for periods of food scarcity and lack of space. In feedlot, concentrated diets with high levels of fast-digesting carbohydrates are used. This review was carried out with the objective of addressing the effect of feedlot diets on the ruminal bacterial population in cattle finished in feedlot. Ruminal bacteria respond rapidly to dietary changes, since they reproduce at intervals of less than 60 minutes. The time of colonization of ruminal bacteria indicates the speed that adhere and penetrate into the food. Rumen microorganisms can be associated with food particles at different times. The particle size of food is one of the important factors for degradation, since it determines the attack surface for microorganisms and directly influences the time of colonization of the food. There is a linear relationship between the body size of the animals and the rumination rate, evidencing that it relates the size of the rumen or digestive tract with the body weight of the animals. Restriction and ladder adaptation protocols are the most used by nutritionists in beef cattle in feedlot The inclusion of additives and probiotics is a valid strategy to improve utilization, as long as it is used at appropriate levels. To minimize the negative effects of changes in diets, it is necessary to gradually adapt the ruminal microbiota, either by the adaptation protocols by ladder or by restriction. Both protocols typically improve health and maximize the performance of animals with 14 days of adaptation.

In vitro investigation of the effect of food texture, particle size, and viscosity on gastric disintegration and emptying

AbstractThe objective of this study was to investigate the influence of particle size, texture, and gastric viscosity on food gastric disintegration and emptying rates. In vitro dynamic gastric digestion was conducted for carrots using a dynamic gastric simulation model. The changes in the texture of carrots and other foods as indicated by bulk resistance, the percent solids emptied, and the particle size distribution were used as parameters to study disintegration kinetics and emptying patterns. The influence of viscosity on food emptying was studied on both indigestible particles (amberlite beads) and digestible solids (carrots). The results indicated medium‐size carrot particles (1.40–2.00 mm) had a greater disintegration and a higher amount of emptying rate when compared to larger (2.00–3.34 mm) and smaller (1.14–1.40 mm) carrot particles. A high correlation exists between the final bulk resistance after 120 min digestion and the amount of solids emptied. Increasing viscosity up to values 8.20 Pa·s improved the particle dispersion for amberlite and carrots and increased rates of solids emptying, while further increase in viscosity hindered emptying of amberlite and carrot solids. The variable emptying rates of both indigestible and digestible solids with viscosity were described with a mathematical model based on particle‐emptying coefficient.

Environment, food residue, and dry cleaning tool all influence the removal of food powders and allergenic residues from stainless steel surfaces

The aim of this study was to investigate how the properties of powered food (particle size and chemical composition), food contact surface (surface roughness), and the environment (ambient relative humidity) impact the efficacy of brushing and scraping in removing wheat flour and non-fat dry milk (NFDM) from stainless steel coupon surfaces. Scraping was significantly less effective than brushing in the removal of powder under all conditions. The number of brush passes (7 ± 2) required to remove NFDM at 0.81 aw was significantly greater than for samples at lower aw levels. Moreover, surface protein residues were still detected following brush removal of NFDM at 0.69 and 0.81 aw. Adhesion and cohesion in samples equilibrated at different relative humidity levels (i.e. different resulting aw) were measured using custom test cells to quantify shear force. Greater adhesion and cohesion were detected for NFDM at higher aw levels. Adhesion and cohesion of NFDM at 0.81 aw were determined to be 129 ± 60 N/m2 and 5418 ± 633 N/m2, respectively. In addition, the particle size of NFDM (75, 180 and 355 μm) and the interaction between particle size and surface roughness (Ra = 0.17 ± 0.09, 0.77 ± 0.12, 1.08 ± 0.37 and 2.05 ± 0.40 μm) had significant effects on residual ATP following brushing. However, surface roughness did not significantly affect cleaning outcomes under the tested conditions. Overall, these findings highlight the potential for allergenic residue retention after conventional dry cleaning using hand tools. By better understanding the baseline efficacy of conventional hand tools used in dry cleaning under different scenarios, more effective cleaning technologies can be developed.

Neuroscience: Flies and grits

Food texture affects palatability. A new study finds that the common dew fly Drosophila melanogaster is also choosy when it comes to food texture. Flies evaluate size and presence of food particles through neurons in the tongue that express the mechanically activated channel protein TMEM63.

Intraspecific variability in the filter mesh size of suspension feeding organisms: the case of invasive Ponto-Caspian corophiids (Crustacea: Amphipoda).

Suspension feeders play pivotal roles in the nutrient cycling of almost all aquatic ecosystems. Since sufficiently large differences in the filter mesh size (FMS) can lead to different food web positions, the inter- and intraspecific variability of this trait might be of community-level importance. The aim of this study was to quantify the range of FMS variation within the three invasive Ponto-Caspian Chelicorophium species based on a large material representing various conditions (1,224 specimens from 40 samples across Central Europe), characterize the components of variation within populations, identify the main factors determining intraspecific differences, and reveal how intraspecific variation affects the FMS overlaps among species. The FMS of the most widespread invader, C. curvispinum, varied within the broadest range (between 2.34–8.28 μm, compared to 2.51–5.97 μm in C. robustum and 1.08–3.23 μm in C. sowinskyi); nevertheless, the contribution of intraspecific plasticity to the invasion success of the species is not evident based on the present study. The within-individual variability of FMS increased with the individual mean of the trait and decreased with body size; however, it showed little differences among samples. The among-individual variation within samples could be partitioned into components related to body size (ontogenetic niche shift/differences among cohorts) and sex (ecological sexual dimorphism) as well as a seemingly random component (individual specialization), varying widely in extent and relative contributions. The FMS of C. curvispinum was significantly larger in the presence of C. sowinskyi than in allopatry, likely reflecting character displacement; however, it did not show further increase when C. robustum was also present. Similar differences could not be observed in C. sowinskyi. The FMS ranges of C. curvispinum and C. robustum never overlapped with that of C. sowinskyi in co-occurrence despite the considerable intraspecific differences among sites, suggesting that their interaction can be seen as a clear case of niche differentiation by food particle size. On the contrary, the strong overlaps observed between C. curvispinum and C. robustum indicate that other factors might play the primary role in their coexistence. The studied species appear to be suitable model organisms for identifying the drivers and mechanisms of FMS variability.

Multidimensional niche differentiation might buffer invasion impacts: the case of oligohaline corophiids (Crustacea: Amphipoda) in the Baltic Sea

Multidimensional niche differentiation might increase the stability of coexistence by reducing overall niche overlap which might have implications on the dynamics of biological invasions. The oligohaline Baltic Seais inhabited by three native and one invasive corophiid amphipod species. These filter feeding crustaceans differ in their substrate preferences and salinity optima which could potentially allow their robust coexistence. However, recent theory predicts that competing species must diverge across all non-substitutable resources (e.g., food and space). We have measured the filter mesh size in the four species (i.e., the distance between bristles on the filtering setae), revealing considerable differences among the three natives (Apocorophium lacustre, Corophium multisetosum and C. volutator), whereas the invasive Chelicorophium curvispinum showed strong overlap with A. lacustre. Theory suggests that the four species cannot coexist robustly due to their overlap in food particle size irrespective of differences in their salinity optima and substrate preferences which is in accordance with observations of local extinctions of A. lacustre. Nevertheless, the stability ensuing from the multidimensional niche differentiation might delay competitive exclusion; i.e., the spatial separation by salinity and substrate types might decrease the intensity of competition for food. Our data for co-occurring populations indicate that A. lacustre might be able to decrease its filter mesh size overlap with C. curvispinum by character displacement and its broader salinity tolerance also might help the native species to persist in the region. However, the niche shift of the species might increase its overlap with C. multisetosum.

Functional morphology of the tongue in the domestic turkey (Meleagris gallopavo gallopavo var. domesticus)

Nowadays, microstructural and ultrastructural analysis of organs of the avian beak cavity points to new aspects of adaptation to food intake through the various feeding groups. These data should undoubtedly be considered in the time of mass production of compound feed in poultry, when many studies analyze the optimal size of food particles and their doses. Galliformes possess complex mechanisms of food collection and transport in the beak cavity. They collect food by pecking and transport food by using catch-and-throw and slide-and-glue mechanisms. The aim of current research is to conduct functional analysis of the tongue in poultry such as domestic turkey in context of type of food, method of food intake, and transport to the esophagus. The study involves observations of macroscopic and microscopic structures of the tongue mucosa by light microscopy and scanning electron microscopy techniques with histochemical analysis of lingual glands. The obtained results showed that the tongue in domestic turkey fills two-thirds of the beak cavity. The lingual structure responsible for pecking is a rigid plate called lingual nail that works similar to a shovel to collect food. The median groove presented on surface of the tongue indicated path of food transport. The conical papillae on border between the lingual body and root are responsible for the last stage of food transport, while the papillae on the sides of root stabilize the path of food transport. For the first time, the presence of 2 types of cornified mucosal epithelia, orthokeratinized and parakeratinized epithelium, was presented. The analysis of occurrence of complex tubular lingual glands indicates production of mucous secretions composed of neutral mucopolysaccharides, with addition of sialomucins and sulfomucins. Mucous secretions moisturize surface of the tongue, thus facilitating the transport of dry food. The presence of sulfur mucopolysaccharides responds to protective function. To sum up, the tongue in domestic turkey is adapted to collect fine or coarse ground feed in form of mash or pellets through pecking and its transport to the esophagus using the slide-and-glue and throw-and-catch mechanisms.

Factors affecting the fate of β-carotene in the human gastrointestinal tract: A narrative review.

Carotenoids and their metabolites play crucial roles in human health such as in immunity, cell differentiation, embryonic development, maintenance of plasma membrane integrity, and gastrointestinal functions, in addition to counteracting night blindness and other eye-related diseases. However, carotenoid bioavailability is highly variable and often low. The bioavailability of β-carotene, among the most frequently consumed carotenoid from the diet, is determined by food matrix related factors such as carotenoid dose, its location in food the matrix, the physical state in food, the presence of other food compounds in the matrix such as dietary fiber, dietary lipids, other micronutrients present such as minerals, and food processing, influencing also the size of food particles, and the presence of absorption inhibitors (fat replacers and anti-obesity drugs) or enhancers (nano-/micro-formulations). However, also host-related factors such as physiochemical interactions by gastrointestinal secretions (enzyme and salts) and other host-related factors such as surgery, age, disease, obesity, and genetic variations have shown to play a role. This review contributes to the knowledge regarding factors affecting the bioavailability of β-carotene (food and host-relegated), as well as highlights in vitro models employed to evaluate β-carotene bioavailability aspects.

The role of the foregut in digestion in the cricket

The role of the foregut (crop and proventriculus) in mechanical processing of food has received little attention in insects. Using the Australian plague locust (Chortoicetes terminifera) and the black field cricket (Teleogryllus commodus) as models, the role of the crop in processing of wheat or rye grass was examined. Interior cuticular structures (spines) of the foregut were described using light and scanning electron microscopy, with locusts having sclerotised structures and crops of crickets being unsclerotised internally. Muscular bands on the exterior surface of the crop part of the foregut are similar in males of both species, but contractions and movements are more forceful in locusts. Passage rate from the foregut is much faster in locusts (&lt;3 h) than in crickets (&gt;3 h). Water within the crop is reduced compared with the water content of fresh grass within the foregut of locusts, but water is increased in cricket crops. Spines within the crops are small relative to the size of food particles in both species. Some spines of locusts contain metals. The slower passage rate from the crop of crickets may be limited by the proventriculus. Foregut structure and food processing facilitates the generalist diet of crickets, but may restrict locusts to consuming softer grasses.

Mouthpart morphology and food habits of a Pampean population ofCloeondipterum(Linnaeus, 1761) (Ephemeroptera: Baetidae)

Knowledge of the feeding habits of aquatic insects and assignation to different functional feeding groups contributes to a better comprehension of aquatic ecosystems. The feeding habits of larval stages (4–6 mm) ofCloeondipterum(Linnaeus, 1761) were studied through mouthpart morphology, gut content and were tested in food particle size preference experiments. The description of the mouthparts consisted in the dissection of them and their observation in an optical microscope. Gut content analysis was carried out by ventral dissection of the thorax to isolate the digestive tract. The content of each larva was homogenized, mounted on slides and observed under an optical microscope at 400× magnification with a graduated eyepiece. Food preference experiments consisted on offering fine particulate organic matter (FPOM) and coarse (CPOM) leaves ofLaurus nobilissimultaneously. Mouthparts are characterized by robust mandibles with well-developed and asymmetric molar surfaces and maxillae and labium with developed palps, with short setae. Gut content ofC.dipterumwas dominated by fine detritus represented by 76.9% (SD = 25.7) of the covered area. Also, in the food preference experiments was detected that FPOM consumption was greater than CPOM. Consequently, we consider that the larval stages ofC.dipterumare functionally classified as collectors-gatherers preferring fine particle size, and secondary scrapers for CPOM manipulation.

Performance of Mastication in Menopausal Women in Palembang

Mastication is the mechanical process of breaking down food in oral cavity. The mastication system involves several components, including saliva and alveolar bone. Salivary flow rate and alveolar bone mineral density have been reported decreased in menopausal women due to the impact of declining estrogen levels. Menopause is the permanent cessation of menstruation resulting from the loss of ovarian follicular activity. The aim of this study was to evaluate the masticatory performance in menopausal women in Kelurahan Talang Kelapa RW 19. This observational experimental study with cross-sectional design involved 36 women, consisting of 18 women and 18 non-menopause women. Masticatory performance was evaluated using a sieve method. Each subject was asked to chew 3 gram peanuts for 20 masticatory strokes, which that procedure was repeated for five times. Masticatory performance was measured using a sieve method which based on the assessment of the size of food particles that have been chewed and filtered over a number 10 mesh sieve. Percentage masticatory performance was obtained by dividing volume of particles passed through the filter with the volume of total particles. The masticatory performance data were analyzed statically with independent samples T test. The mean masticatory performance score was 13,71%, in menopausal women and 30,62% in non-menopausal women. It was found that masticatory performance in menopausal women was significantly lower when compared to non-menopausal women (p0,05). It may be concluded that menopause decreased the masticatory performance.