METHOD TO INVESTIGATE DIFFERENCES IN CHEWING BEHAVIOUR IN HUMANS

This study examines whether the patterns of muscle activity measured from the masticatory muscles during a chew are sufficiently reproducible to form the basis of a characterisation of chewing behaviour, and whether they express the degree of variation evident between individuals. Electromyograph (EMG) readings of the repetitive activity involved in chewing gum were analyzed for 10 subjects, each on three separate occasions. For each individual the temporal aspects of the chew cycle (duration of the activity burst, period between bursts of activity and duration of the complete cycle) were reproducible between EMG recording sessions. Consistency was also found for amplitude aspects of the EMG record: mean voltage within the activity burst, maximum voltage, and the area under the EMG trace. For all six parameters there was significant variation between subjects. The study showed that variations in the chewing pattern, as occur for chewing on opposite sides of the mouth, were reflected in the 6 EMG parameters examined, and that the changes elicited were different for each individual. Moreover, encouraging subjects to concentrate on the act of chewing caused them to modify their chewing pattern, highlighting the importance of avoiding such attention when assessing habitual chewing behaviour.     

Comparison of electromyographic pattern of sensory experts and untrained subjects during chewing of Mahon cheese

Use of electromyography (EMG) to monitor mastication is a relatively new concept in assessing food physical and sensory properties. Although expert assessment of cheese characteristics is widely used, the effect of training in sensory analysis on mastication patterns, as assessed using EMG is not well known. Nine samples of the same Mahon cheese (60 days ripening) were given to 24 subjects (8 experts, 16 untrained) and EMG recorded for each chewing sequence. Three samples were tested in a single session by each subject, and three sessions carried out on different days. EMG was recorded from four masticatory muscles for each subject. From EMG records the following was extracted: number of chews, chewing time, mean and maximum voltage of EMG bursts (i.e. chews) across chewing sequence, chewing work and chewing rate. No gender bias was found for the EMG parameters considered, therefore, as regards gender, each group was considered to be homogeneous. Variability within-subjects across samples was greater for experts than untrained subjects. Significant differences in chewing time, chewing work and chewing rate were found between the expert and untrained groups. Data analysis of the three sessions showed an influence of cognitive constructs, mediating states, on the chewing process. The experts were found to be goal driven as to their mastication process. Experts showed no significant differences between sessions, untrained subjects were found to vary their EMG output in successive sessions for number of chews, chewing time, mean voltage, and chewing work.     

Characterising the release of flavour compounds from chewing gum through HS-SPME analysis and mathematical modelling

The headspace solid-phase microextraction (HS-SPME) technique combined with GC–MS was evaluated to study 33 selected flavour compounds released from chewing gum. The operating conditions of SPME were optimised, including different fibres (PDMS, DVB/CAR/PDMS, PA and PDMS/DVB), sample size, extraction time and temperature. The results indicated that while HS-SPME was a rapid and valuable technique, poor reproducibility occurred under all conditions. It was found that this deficiency could be alleviated by utilising mathematical modelling techniques, an approach which had not been previously used in the analysis of flavour compounds in chewing gum by HS-SPME. Compared to the instrumental analysis data themselves, the models provided more insights to the release behaviour of flavour compounds from chewing gum and the more reproducible kinetic rate constants might be used for comparing the release of different compounds or the same compound under different conditions.     

The effect of flavour modulators on chewing gum flavour duration

This study investigated the impact of flavour modulators on dynamic flavour perception, salivation and chewing behaviour of chewing gum. Thirty-nine participants chewed gum for 15 min while assessing flavour intensity, chewing patterns and saliva flow rate. Four flavour modulators (Cooling, Tingling, Salivating and Warming) were added to a citrus-flavoured gum and compared with a control gum, citrus flavour only. Flavour modulators increased flavour duration as measured by flavour intensity half-time; the time needed to reduce the flavour intensity by half. The ‘Salivation’ modulator had the smallest effect and ‘Warming’ had the largest effect on flavour duration. Salivary flow rate was significantly increased by the flavour modulators and was highly correlated with the flavour duration. Chewing behaviour was not affected by the modulators. We conclude that the interaction between the citrus flavour, saliva and flavour modulators (Intensates® flavours) increased the perceived flavour duration during chewing by up to 86% compared with Control.     

Mastication of heterogeneous foods: Peanuts inside two different food matrices

We investigated chewing behaviour and particle size outcome in the oral processing of heterogeneous foods using peanuts embedded within two types of food matrices. Eight subjects, selected according to strict dental and mastication criteria, were served four different model foods. Each model food comprised one of two matrices of different physical properties (chocolate and gelatine gel) which were embedded with one of two physically different particles (peanuts with low moisture or high moisture content). A standard volume of each model food was chewed to the point of swallowing and expectorated and the number of chews and chewing time was recorded. The matrix of the expectorated bolus was washed away to isolate the peanut fragments, and the particle size distributions of the peanut fragments were determined using image analysis. A Rosin-Rammler function was fitted to the cumulative distribution data of each bolus to derive particle size parameters (d₅₀ and broadness (b)).Results showed the properties of one food component (the matrix) can influence the breakdown of another food component (the peanuts) in a heterogeneous system. The properties of the matrix caused differences in mastication (measured in terms of the number of chews, chewing duration, and frequency) and broadness of the peanut particle size distribution, but did not influence the final d₅₀ of the peanut particle size distribution. Conversely the physical properties of the embedded peanut influenced the d₅₀ of the particle size distribution but had no effect on chewing behaviour. It is likely that properties of the matrix influenced the rate at which particles of various sizes were selected for chewing (known as the selection function), whereas the physical properties of the peanuts influenced extent of breakage when the teeth made contact with the particles (known as the breakage function).     

Electromyography of Eating Apples: Influences of Cooking, Cutting, and Peeling

ABSTRACT: The mastication of 7 differently prepared apple samples (raw pieces peeled and unpeeled, sliced, grated, cooked pieces with and without peel, and half-cooked pieces, 10 g each) was evaluated using electromyography (EMG). Eleven subjects participated in the EMG recording of both sides of the masseter and temporal muscles while eating samples normally. Only the grated sample reduced the number of chewing strokes and muscle activity before swallowing. In contrast, the thin apple slices produced significantly shorter contraction duration and cycle time only during the 1st 5 chewing strokes. The EMG duration and cycle in subsequent chews, as well as the other parameters, did not significantly differ between slices and pieces. Cooked apples exhibited significantly lower EMG amplitude and muscle activity per chew than their raw counterparts; however, there was no evidence of reduced total muscle activity required for swallowing. Raw and cooked apples with peel yielded significantly greater EMG amplitude and longer duration than those without peel. These findings suggest that appropriate preparation is necessary for people with various mastication abilities: grated for very low ability, cooked for those with weak chewing force, and unpeeled for mastication training.     

Anti-stress effects of chewing gum prepared with yeast hydrolysate

In this study, we investigated the anti-stress effects of chewing gum prepared with yeast hydrolysate (SCP) in the general Korean population using heart rate value (HRV) analysis and the Beck depression inventory (BDI) and Beck anxiety inventory (BAI). Four different kinds of chewing gum (weight 960 ± 2 mg) were designed: three with different concentrations of SCP (30, 85, and 250 mg/piece) combined with xylitol and a placebo chewing gum. Displacement studies of ³H-paroxetine showed that SCP interacted with serotonin transporters with an IC₅₀ of 1.72 mg/mL. In the placebo group, there were significant differences in the BDI and BAI scores before and after chewing gum (p < 0.05). There were also significant differences in the SCP groups in BDI and/or BAI scores between before and after chewing gum (p < 0.05). In addition, the SCP-30 and 85 groups were significantly different in low frequency (LF) or standard deviation of RR interval (SDNN) value, respectively, before and after the act of chewing gum (p < 0.05). After the chewing gum tests, some HRV (HR, SDNN, TP, and HF) were significantly different between the groups. In particular, the SCP-85 group was significantly different in HR, SDNN, TP, and HF compared to the placebo group (p < 0.05). In the improvement of BAI and BDI scores after the chewing gum test, the SCP-30 and SCP-250 groups exhibited significant improvements in BAI scores compared to placebo (p < 0.05). These findings suggest that SCP intake may be associated with a reduced risk of depression and stress. The SCP might have a synergistic effect on the anti-stress properties of chewing gum.     

Enzyme-modified guar gum/xanthan gelation: An analysis based on cascade model

The gel properties of a mixture of enzymatically-modified guar gum (EMG) and xanthan (XG) were investigated. The guar gum sample treated with α-galactosidase to remove galactose residues had a mannose/galactose ratio of 3.02, and was capable of forming a synergistic gel with xanthan. The concentration-dependent and temperature-dependent modulus data for the EMG/XG gel were analyzed by the two-component cascade model which assumed a heterotypic association between segments of EMG and XG. The optimal functionalities (number of cross-linking sites per chain), f_EMG and f_XG, were found to be 300 and 30, respectively. The former is equal to the number of segment size with more than six unsubstituted mannose residues in a galactomannan backbone, while the latter corresponds to a cross-link density of one per 37 repeating units in a xanthan molecule. The cascade analysis of the composition dependence of critical gelling concentration was performed by introducing the effect of the homotypic association of XG or EMG, which became significant in the gel point measurement. The enthalpy change per cross-link for the heterotypic association was found to be two times higher than that for the homotypic association.     

CHEWING PATTERNS OF VARIOUS TEXTURE FOODS STUDIED BY ELECTROMYOGRAPHY IN YOUNG AND ELDERLY POPULATIONS

The effects of food texture on the chewing patterns of elderly and young people, masticatory recordings using electromyography (EMG) were carried out. Fourteen French adults (mean 29.4 years) and 23 elderly (mean 67.7 years) participated. Six food products (rice, beef, cheese, crispy bread, apple and peanuts) were tested. The chewing pattern of elderly subjects was characterized by a significant increase of number of chews and chewing duration for all foods except rice. Whatever the food type, muscle activity per chew (mean amplitude × burst duration) was lower for elderly than for young subjects. Single chews appeared less effective for food reduction in elderly than in young subjects. This can be partly compensated for by increasing the chewing duration and number of chews. No significant difference was found between both groups of subject for the total amount of EMG activity required prior to swallow whatever the food chewed.     

Texture analysis of Red Delicious fruit: Towards multiple measurements on individual fruit

The sensory texture of Red Delicious apples was studied using single point and time–intensity (TI) methods together with penetrometers and in vivo techniques. Testing was performed in two trials on a per fruit basis, not with fruit batches. The standard penetrometer was significantly correlated (p < 0.05) to sensory hardness, juiciness, mealiness, crunchiness and degree of breakdown, but not to skin toughness. Facial muscle activity during chewing was collected with electromyography (EMG) together with spit outs for individuals. Parameters such as work done during chewing were extracted from the full EMG signals, and some were found to be related significantly (p < 0.05) to the penetrometer data and to sensory hardness. The aspect ratio of expectorated particles related significantly (p < 0.05) to sensory hardness and skin toughness.Principal component analysis shows that 76% of the variance in the combined data set was explained by seven components in Trial 1 and 73% by six components in Trial 2. The first component in both trials was described, principally by hardness, mealiness and the penetrometer value. The second component was described by the EMG signal parameters in Trial 1, and the apple skin properties in Trial 2. Sensory terms hardness, mealiness, crunchiness and juiciness were inter-correlated which may indicate that the texture of Red Delicious apples is perceived as mainly one-dimensional.     

EFFECT OF REMOVABLE PARTIAL DENTURES REPLACING PRIMARY MOLARS ON MASTICATION OF FOODS WITH VARIABLE TEXTURE

ABSTRACT

This study investigated the effects of a prosthetic appliance on the chewing function, evaluating the electrical activity of masseter and temporal muscles to characterize the chewing process using an artificial test material. Moreover, the chewing behavior with foods of different textures (chewing gum, raw carrot, cheese, banana and industrialized toast) was evaluated. Twenty‐three partially edentulous children (12 girls and 11 boys, 7.10 ± 0.74 year‐old) participated. Electromyography and chewing behavior were determined before and 6 months after the appliance placement. During habitual chewing, the muscle activity values after the 6 months were higher (P < 0.001). Electromyographic recording (EMG) values were not correlated with body variables. At the two evaluations, significant differences occurred in the number of cycles, swallowing threshold and amount of food ingested for soft and hard foods. The increase in EMG values and the improvement in chewing natural foods were able to demonstrate the influence possibility of the partial removable denture on the muscles and masticatory functions in children.

PRACTICAL APPLICATIONS

Masticatory muscles respond to the stimulus received. Chewing is a complex neuromuscular task, in which an extrinsic stimulus, such as food, provokes an intrinsic response involving the oral structures. Apart from the subject‐related variables, food consistency, texture and volume seem to be particularly significant in determining the characteristics of chewing in oral partial or total denture wearers to enable the outcome on the masticatory system function to be verified. In children, these considerations are important, since the oral sensorimotor pathway matures throughout childhood in concert with the continued acquisition of complex motor skills. Thus, it is expected that partial removable denture with good occlusal relations and good retention can not only restore mastication, but also help to maintain the health of the masticatory system since the motor system could be exercised properly.     

CHARACTERISATION OF PATTERNS OF CHEWING BEHAVIOUR IN HUMAN SUBJECTS AND THEIR INFLUENCE ON TEXTURE PERCEPTION

Electromyography was used as a noninvasive and unobtrusive technique to characterise chewing patterns for a range of foods. Differences between subjects for a variety of aspects of chewing sequence are recorded for a range of foods (carrot, apple, roast pork, salami, biscuit and toast). Identifiable subgroups of subjects differing in chewing behaviour existed within the random sample of 52 dentate subjects. The five subgroups accounted for 52%, 21%, 11%, 10% and 6% of the sample population. Major discriminating factors between the behavioural groups lie in their chewing time and the muscle work rate during chewing. Sensory ratings for firmness and rubberiness of model foods differed significantly between the subjects exhibiting different chewing behaviours. Chewing behaviour may influence consumers' perceptions about the texture of a food.     

Characterization of bread breakdown during mastication by image texture analysis

The methods currently used to characterise food breakdown during mastication are not easily applicable to cohesive and heterogeneous products such as white bread (baguettes). During this study, we investigated the applicability of image texture analysis to characterising the kinetics of bread bolus formation during chewing. Food boluses were collected from five subjects chewing four different breads after 10, 20 and 30 chewing cycles or at swallowing. Images were acquired and analysed using the Grey level co-occurrence matrix (GLCM) method. Food boluses were successfully discriminated: 60–73% of the images were correctly classified into their respective chewing cycles. Incorrect classifications arose from overlapping between subsequent cycles. Among the texture features the contrast was identified as being the best marker of food degradation. Different kinetics of bolus formation were observed between breads. This method revealed specific patterns of food degradation between subjects, which could be explained by their mastication behaviour and chewing efficiency.     

INFLUENCE OF CHEWING AND SWALLOWING BEHAVIOR ON VOLATILE RELEASE IN TWO CONFECTIONERY SYSTEMS

Electromyography, electroglottography and turbine airflow technology were used to characterize the chewing, swallowing and breath flow profiles of 35 subjects during the consumption of two different (a gum Arabic‐ and carrageenan‐based) confectionery chews. Simultaneous volatile release measurements were obtained using atmospheric pressure chemical ionization mass spectrometry. Subgroups of subjects displaying different eating characteristics were identified for both products. Parameters accounting for the maximum variance (product 1, 42% and product 2, 52%) between the subgroups were chewing force, chewing rate, proportion of work and total number of chews. Volatile release measurements were significantly different between the subgroups from product 1. The impact of the different eating characteristics on volatile release from product 2 was less defined, and postulated to be a result of the contrasting textural properties. Manipulating in vivo breakdown of chewy confectionery products, by texture modification, may influence consumer's volatile release and subsequent flavor perception.     

INFLUENCE OF CHEWING EFFICIENCY ON TEXTURE AND FLAVOUR PERCEPTIONS OF FOOD

This study examined the effect of differences in chewing efficiency on selected panellists' perceptions of the stickiness and flavour of cooked pasta. Chewing efficiency was measured by the degree of breakdown of an almond, and weight loss of chewing gum after predetermined numbers of chews. Pasta was cooked for various lengths of time in tomato juice to provide a series of samples varying in texture and flavour. The attributes considered in this study were clearly understood and detected in all of the samples by all the subjects. Nevertheless the subjects differed in the time intensity representations of their perceptions of these attributes. Differences in the efficiencies with which subjects break down food in the mouth may account for the abilities of subjects to distinguish between samples in terms of texture and flavour.     

普洱茶风味口香糖的研制

以普洱茶为原料,通过浸提、浓缩、干燥等工艺制成普洱茶粉,与产品胶基混合制成普洱茶风味口香糖.本文主要探讨普洱茶汁浓缩、干燥的最佳工艺,以及茶粉用量对口香糖品质的影响.实验结果表明,普洱茶汁最佳浓缩条件为:β-环糊精3.0%、蒸发温度55℃,真空度-0.08MPa,最佳干燥条件为:3倍原茶叶重量的蔗糖、蒸发温度55℃、真空度-0.09MPa、7h.口香糖生产工艺中荼粉最佳添加量为50g/300g胶基.     

Extraction and physicochemical characterisation of polysaccharide gum from Yanang (Tiliacora triandra) leaves

Yanang (Tiliacora triandra) is a vegetable used in many cuisines of the northeast of Thailand and Lao People’s Democratic Republic. This paper reports the optimised extraction and some physicochemical characteristics of polysaccharide gum from Yanang leaves. The optimised extraction condition was at the leaf:water ratio of 1:6.6, 85 °C, and 100 min extraction time. The major monosaccharide constituent of Yanang gum was xylose, together with substantial amounts of other neutral sugars. The FT-IR spectra of Yanang gum were similar to that of xylan. Yanang gum exhibited shear-thinning flow behaviour and the extent of shear-thinning was concentration dependent. The mechanical spectra of Yanang gum at low concentration (0.5%) were typical of semi-diluted to concentrated solutions. However, with increasing concentration, the solution behaved like a weak gel.     

Variables Influencing Chewing Electromyography Response in Food Texture Evaluation

Food choice is linked to many characteristics, among which texture is one of the most important. As a consequence, texture is a quality parameter that needs to be understood on a global perspective, including physical and psychological aspects. Texture perception is gained from a complex process of chewing, and not from a single action. Thus, there is a need for techniques that consider the whole process of chewing. Among those techniques, electromyography (EMG) seems promising. Different variables influence the chewing response as registered through EMG. Some of those variables are linked to the experimental set-up, where there is a need for standardization as well as data processing procedures. Other variables are linked to subject characteristics, both physical (e.g., facial anatomy, age) and psychological (e.g., personality, cognitive processes). Experimental planning can also constitute a source of variability, the number of products and trials per session being important items. The way the EMG signals are processed (parameters from EMG records) also must be considered in order to extract reliable and consistent conclusions. Because no standard practices have been established for the use of EMG in food texture assessment, it is important to review how this technique has been used, the variables involved, and the meaning or concepts associated with the outputs.     

Determination of sucralose in foods by anion-exchange chromatography and reverse-phase chromatography

Simple and rapid methods for the determination of sucralose in foods were developed using anion-exchange chromatography (AEC) with pulsed amperometric detection and reverse-phase HPLC with refractive index detection. Sucralose was extracted with water or methanol, and the extracted solution was cleaned up on a Sep-Pak C18 cartridge and a Sep-Pak Alumina N cartridge. The AEC separation was performed on a CarboPac PA1 column (4.0 mm i.d x 250 mm) using 100 mmol/L sodium hydroxide-50 mmol/L sodium acetate solution as the mobile phase at a flow rate of 1.0 mL/min. The recoveries of sucralose from foods were 80.6-102.0%, and quantitation limits from foods except chewing gum were 0.5 microgram/g (2 micrograms/g from chewing gum). The reverse-phase HPLC separation was performed on an Inertsil ODS-3V column (4.6 mm i.d x 150 mm) using methanol-water (25:75) as the mobile phase at a flow rate of 1.0 mL/min. The recoveries of sucralose from foods were 80.2-121.2%, and quantitation limits from foods except chewing gum were 5 micrograms/g (20 micrograms/g from chewing gum).