- Email: [email protected]
46. Association between chewing efficiency and mastication patterns for meat
320
Abstracts of Oral Presentations
the microstructural parameters - volume of small and large pores and volume of particles - and the sensory parameters - grainy appearance, gritty, creamy, and the degree of falling apart. The logarithmic dependence indicates that the human perception of textural properties is very sensitive to fine deviations in small particles. The particle size varied around one micron. The volume of pores was correlated to the grainy appearance of the newly-cut surface and the description of ‘falling apart’, which probably relates to the size of the pores.
44. TIME-INTENSITY AS A TOOL FOR THE MEASUREMENT OF PORK TENDERNESS Gail Butler, Linda M. Poste and Deborah A. Mackie, Centre for Food and Animal Research, Building 94, Agriculture and Agri-Food Canada, Ottawa, ON, Canada KlA OC6
Most sensory techniques require assessors to summarize their response over time and then provide a single time-averaged rating or score for a particular attribute. Time-intensity allows assessors to continuously record their sensory responses over time. In the texture analysis of meat, tenderness is an attribute that changes significantly over time from the initial bite, through the masticatory phase to the residual phase before swallowing. In this study, both time-averaged and time-intensity measurements were recorded on a line-scale and compared. Thirty biceps femoris gilt roasts representing two breeds and cooked at three oven temperatures were evaluated. Eight trained assessors evaluated cores, taken both perpendicular and parallel to the muscle fibre, and slices sampled from each roast. For the time-averaged measurement assessors recorded their perception of tenderness after a chew count of eight on a 15 cm line. For the time-intensity measurement assessors recorded, at a separate session, their evaluation of tenderness from an initial bite to swallowing on a computer screen by moving a cursor along a 15 cm line. After standardizing duration of assessment and range of intensity, individual curves were averaged for visual assessment. Parameters summarizing the curves were analyzed (area under the curve, initial, minimum, mean, maximum, and terminal intensity, range of intensity, slope from the initial bite to swallowing, time at minimum and maximum and duration of assessment) by analyses of variance. Results based on these parameters were comparable to those of the time-averaged data. In addition to breed and sample type (core vs. slices), differences found in both data sets, the time-intensity data indicated differences between the parallel and perpendicular cores that the time-averaged data did not. The time-intensity curves also clearly illustrate the temporal features of the perception of tenderness.
45. INDIVIDUALITY OF UNDERSTANDING AND ASSESSMENT OF SENSORY ATTRIBUTES OF FOODS Wendy E. Brown, Keith Langley, Laurence Mioche, Sue Marie, Stephane Gerault and Denise Braxton Institute of Food Research, Earley Gate, Whiteknights Road, Reading RG6 2EF, U.K. Individual differences between subjects often represent a significant factor in sensory data, particularly when the subjects are consumers untrained in sensory methods. Variation between individuals may indicate that some subjects are unable to report accurately their sensory perceptions. However, when applied to the sensory modalities of texture or flavor of foods, for which an interaction between the subject and the food is prerequisite, variability may arise from subjects using: a) different criteria on which to judge the attribute, and/or b) the same criteria but causing the attribute to be expressed to different extents by virtue of the way they manipulate the food in the mouth. Asking subjects to describe how a particular attribute changes during eating may help us to explore how sensory perceptions of food arise. Twenty subjects were asked to monitor the tenderness of a range of samples of meat throughout the chewing period, using a Time-Intensity (TI) method. 50% indicated that tenderness increased progressively throughout the chewing time. 10% indicated that tenderness increased rapidly during the first few seconds and thereafter decreased progressively to the point of swallowing. 25% indicated that tenderness reached a plateau within a few seconds which was maintained throughout the chewing period. The remaining subjects gave indistinct TI profiles. Some subjects showed significant correlations between their sensory ratings and tensile properties of the samples measured instrumentally, whilst others showed significant correlations with shear strength. Mastication patterns, as revealed by electromyographic recordings from the masticatory muscles, varied markedly between the subjects in the study. Significant correlations between sensory ratings and mastication markers were found for all subjects, but the relevant markers differed between individuals. These findings support the hypothesis that variations between individuals in perceived texture may arise from both of the above mentioned sources.
46. ASSOCIATION BETWEEN CHEWING EFFICIENCY AND MASTICATION PATTERNS FOR MEAT Denise Braxton, Celine Dauchel and Wendy Brown, Consumer Sciences Department, Institute of Food Research, Earley Gate, Whiteknights Road, Reading RG6 2EF, U.K.
Abstracts of Oral Presentations The aim of this study was to investigate whether measured chewing efficiency was related to characteristics of an individual’s chewing pattern. The chewing efficiency for 20 dentate volunteers was quantified by the weight loss from chewing gum after 100 chewing strokes and the particle size distribution of a whole, blanched almond chewed for ten strokes. Characteristics of the mastication patterns for each subject were measured from electromyographs (EMGs) recorded bilaterally for the masseter and anterior temporalis muscles during eating. Samples of roast beef and pork exhibiting a range of tenderness were used within the study. Four subgroups of subjects, differing in their relative efficiencies with the almond and chewing gum, were identified from the combined chewing efficiency data in terms of HiHi, LoLo, HiLo, and LoHi. Mastication parameters, determined from the EMG records, included the number of chews, total chewing time, chew rate, chew work and chew work rate for the sum of the four muscles. Analysis of variance showed that the chewing efficiency groups differed significantly in all the EMG parameters, except for chew rate, for the meat samples. The data demonstrated strong links between subjects’ chewing efficiencies with the two products and the combination of chewing time and work rate during mastication of the meat samples. The influence of these differences on perception of tenderness will be described.
47. EFFECTS OF VARIOUS FOOD TEXTURES ON HUMAN MANDIBULAR MOVEMENTS Marie-Agrks Renon,
Peyron, Laurence Mioche and Philippe
INRA, Meat Research Station, Genes-Champanelle, France
Theix 63122 Saint-
Food texture is known to influence several mastication parameters such as forces and kinematics. However, no relationship has been established between any particular texture property and its consequences on the jaw movements. This study was thus conducted to examine whether jaw movement recordings could be a reliable method to investigate food texture properties. Jaw movements were recorded in the frontal plane with an electromagnetic system. The subject’s head was placed in a magnetic field. Two receiver coils were stuck on the central incisors, one on the mandibular arch and the other on the maxillary arch for collecting head movement signals. The signal collected with the mandibular coil was corrected by subtracting head movements. To investigate the influence of texture on jaw movements, five foods were chosen to display various rheological behaviors. Chocolate represented brittle foods, two cheeses differing in hardness brought plastic fractures, meat and coconut were chosen for their fibrous character, coconut presenting a more brittle aspect. All samples were prepared in a
321
domino shape ( 1.8 x 1.8 x 1 cm3). Six replicates of each food were randomly presented. Chewing gum was used to stabilize the subject. Ten subjects free of dental pathology were asked to perform free style mastication. Durations, amplitudes and maximal velocities of opening and closing phases were measured. Jaw movement parameters allowed to discriminate the different food products. The most striking differences between products occurred with the lateral component of the jaw movement. The main finding of this experiment was the demonstration that masticatory jaw movements differed with the type of food chewed and thus this method could be of great interest for objective studies of food texture.
48. THE IMPACT OF DEALCOHOLIZATION ON THE FLAVOR OF WINE: RELATING THE CONCENTRATION OF AROMA COMPOUNDS TO SENSORY DATA USING PLS ANALYSIS Ulrich Fischer and Ralf G. Berger, Staatliche Lehr- und Forschungsanstalt, 67435 Neustadt, Germany
Breitenweg
7 1,
A total of three commercial wines were dealcoholized by vacuum distillation and reverse osmosis. Chemical (GC, GC-MS) and sensory analysis (Descriptive Analysis, GCO) investigated the base wine, both dealcoholized wines, and the respective product streams distillate and permeates. While both dealcoholization processes reduced significantly fruity odors, the musty, sweaty and vegetative attributes were enhanced. Both methods reduced perceived bitterness and aftertaste, but increased sourness. Upon adding neutral spirit to the dealcoholized wines and raising ethanol content to its original strength, all taste attributes were increased up to the level found in the base wine. In contrast, nearly all odor attributes, including the retronasal perception of fruitiness by mouth, were not altered by ethanol addition. The mass balance of aroma compounds revealed for vacuum distillation an overall reduction of 75%, which was mainly due to the transfer of esters and alcohols into the distillate. More polar lactones, phenols and short chain fatty acids however, were highly retained. Thus, boiling point and polarity mainly determined the degree of removal. In contrast, during reverse osmosis, permeation and absorption to the membrane occurred evenly across all different compound classes and accounted for 40% loss of total aroma compounds. GCO methodology employed the human nose as biological detector to select odor active aroma compounds, describe their odor quality, and determine their odor threshold by a dilution assay. Using PLS regression analysis, the chemical data set (screened according to flavor dilution values determined by GCO) was utilized to model sensory intensities. It was clearly suggested that the lack of fruitiness in
Abstracts of Oral Presentations
the microstructural parameters - volume of small and large pores and volume of particles - and the sensory parameters - grainy appearance, gritty, creamy, and the degree of falling apart. The logarithmic dependence indicates that the human perception of textural properties is very sensitive to fine deviations in small particles. The particle size varied around one micron. The volume of pores was correlated to the grainy appearance of the newly-cut surface and the description of ‘falling apart’, which probably relates to the size of the pores.
44. TIME-INTENSITY AS A TOOL FOR THE MEASUREMENT OF PORK TENDERNESS Gail Butler, Linda M. Poste and Deborah A. Mackie, Centre for Food and Animal Research, Building 94, Agriculture and Agri-Food Canada, Ottawa, ON, Canada KlA OC6
Most sensory techniques require assessors to summarize their response over time and then provide a single time-averaged rating or score for a particular attribute. Time-intensity allows assessors to continuously record their sensory responses over time. In the texture analysis of meat, tenderness is an attribute that changes significantly over time from the initial bite, through the masticatory phase to the residual phase before swallowing. In this study, both time-averaged and time-intensity measurements were recorded on a line-scale and compared. Thirty biceps femoris gilt roasts representing two breeds and cooked at three oven temperatures were evaluated. Eight trained assessors evaluated cores, taken both perpendicular and parallel to the muscle fibre, and slices sampled from each roast. For the time-averaged measurement assessors recorded their perception of tenderness after a chew count of eight on a 15 cm line. For the time-intensity measurement assessors recorded, at a separate session, their evaluation of tenderness from an initial bite to swallowing on a computer screen by moving a cursor along a 15 cm line. After standardizing duration of assessment and range of intensity, individual curves were averaged for visual assessment. Parameters summarizing the curves were analyzed (area under the curve, initial, minimum, mean, maximum, and terminal intensity, range of intensity, slope from the initial bite to swallowing, time at minimum and maximum and duration of assessment) by analyses of variance. Results based on these parameters were comparable to those of the time-averaged data. In addition to breed and sample type (core vs. slices), differences found in both data sets, the time-intensity data indicated differences between the parallel and perpendicular cores that the time-averaged data did not. The time-intensity curves also clearly illustrate the temporal features of the perception of tenderness.
45. INDIVIDUALITY OF UNDERSTANDING AND ASSESSMENT OF SENSORY ATTRIBUTES OF FOODS Wendy E. Brown, Keith Langley, Laurence Mioche, Sue Marie, Stephane Gerault and Denise Braxton Institute of Food Research, Earley Gate, Whiteknights Road, Reading RG6 2EF, U.K. Individual differences between subjects often represent a significant factor in sensory data, particularly when the subjects are consumers untrained in sensory methods. Variation between individuals may indicate that some subjects are unable to report accurately their sensory perceptions. However, when applied to the sensory modalities of texture or flavor of foods, for which an interaction between the subject and the food is prerequisite, variability may arise from subjects using: a) different criteria on which to judge the attribute, and/or b) the same criteria but causing the attribute to be expressed to different extents by virtue of the way they manipulate the food in the mouth. Asking subjects to describe how a particular attribute changes during eating may help us to explore how sensory perceptions of food arise. Twenty subjects were asked to monitor the tenderness of a range of samples of meat throughout the chewing period, using a Time-Intensity (TI) method. 50% indicated that tenderness increased progressively throughout the chewing time. 10% indicated that tenderness increased rapidly during the first few seconds and thereafter decreased progressively to the point of swallowing. 25% indicated that tenderness reached a plateau within a few seconds which was maintained throughout the chewing period. The remaining subjects gave indistinct TI profiles. Some subjects showed significant correlations between their sensory ratings and tensile properties of the samples measured instrumentally, whilst others showed significant correlations with shear strength. Mastication patterns, as revealed by electromyographic recordings from the masticatory muscles, varied markedly between the subjects in the study. Significant correlations between sensory ratings and mastication markers were found for all subjects, but the relevant markers differed between individuals. These findings support the hypothesis that variations between individuals in perceived texture may arise from both of the above mentioned sources.
46. ASSOCIATION BETWEEN CHEWING EFFICIENCY AND MASTICATION PATTERNS FOR MEAT Denise Braxton, Celine Dauchel and Wendy Brown, Consumer Sciences Department, Institute of Food Research, Earley Gate, Whiteknights Road, Reading RG6 2EF, U.K.
Abstracts of Oral Presentations The aim of this study was to investigate whether measured chewing efficiency was related to characteristics of an individual’s chewing pattern. The chewing efficiency for 20 dentate volunteers was quantified by the weight loss from chewing gum after 100 chewing strokes and the particle size distribution of a whole, blanched almond chewed for ten strokes. Characteristics of the mastication patterns for each subject were measured from electromyographs (EMGs) recorded bilaterally for the masseter and anterior temporalis muscles during eating. Samples of roast beef and pork exhibiting a range of tenderness were used within the study. Four subgroups of subjects, differing in their relative efficiencies with the almond and chewing gum, were identified from the combined chewing efficiency data in terms of HiHi, LoLo, HiLo, and LoHi. Mastication parameters, determined from the EMG records, included the number of chews, total chewing time, chew rate, chew work and chew work rate for the sum of the four muscles. Analysis of variance showed that the chewing efficiency groups differed significantly in all the EMG parameters, except for chew rate, for the meat samples. The data demonstrated strong links between subjects’ chewing efficiencies with the two products and the combination of chewing time and work rate during mastication of the meat samples. The influence of these differences on perception of tenderness will be described.
47. EFFECTS OF VARIOUS FOOD TEXTURES ON HUMAN MANDIBULAR MOVEMENTS Marie-Agrks Renon,
Peyron, Laurence Mioche and Philippe
INRA, Meat Research Station, Genes-Champanelle, France
Theix 63122 Saint-
Food texture is known to influence several mastication parameters such as forces and kinematics. However, no relationship has been established between any particular texture property and its consequences on the jaw movements. This study was thus conducted to examine whether jaw movement recordings could be a reliable method to investigate food texture properties. Jaw movements were recorded in the frontal plane with an electromagnetic system. The subject’s head was placed in a magnetic field. Two receiver coils were stuck on the central incisors, one on the mandibular arch and the other on the maxillary arch for collecting head movement signals. The signal collected with the mandibular coil was corrected by subtracting head movements. To investigate the influence of texture on jaw movements, five foods were chosen to display various rheological behaviors. Chocolate represented brittle foods, two cheeses differing in hardness brought plastic fractures, meat and coconut were chosen for their fibrous character, coconut presenting a more brittle aspect. All samples were prepared in a
321
domino shape ( 1.8 x 1.8 x 1 cm3). Six replicates of each food were randomly presented. Chewing gum was used to stabilize the subject. Ten subjects free of dental pathology were asked to perform free style mastication. Durations, amplitudes and maximal velocities of opening and closing phases were measured. Jaw movement parameters allowed to discriminate the different food products. The most striking differences between products occurred with the lateral component of the jaw movement. The main finding of this experiment was the demonstration that masticatory jaw movements differed with the type of food chewed and thus this method could be of great interest for objective studies of food texture.
48. THE IMPACT OF DEALCOHOLIZATION ON THE FLAVOR OF WINE: RELATING THE CONCENTRATION OF AROMA COMPOUNDS TO SENSORY DATA USING PLS ANALYSIS Ulrich Fischer and Ralf G. Berger, Staatliche Lehr- und Forschungsanstalt, 67435 Neustadt, Germany
Breitenweg
7 1,
A total of three commercial wines were dealcoholized by vacuum distillation and reverse osmosis. Chemical (GC, GC-MS) and sensory analysis (Descriptive Analysis, GCO) investigated the base wine, both dealcoholized wines, and the respective product streams distillate and permeates. While both dealcoholization processes reduced significantly fruity odors, the musty, sweaty and vegetative attributes were enhanced. Both methods reduced perceived bitterness and aftertaste, but increased sourness. Upon adding neutral spirit to the dealcoholized wines and raising ethanol content to its original strength, all taste attributes were increased up to the level found in the base wine. In contrast, nearly all odor attributes, including the retronasal perception of fruitiness by mouth, were not altered by ethanol addition. The mass balance of aroma compounds revealed for vacuum distillation an overall reduction of 75%, which was mainly due to the transfer of esters and alcohols into the distillate. More polar lactones, phenols and short chain fatty acids however, were highly retained. Thus, boiling point and polarity mainly determined the degree of removal. In contrast, during reverse osmosis, permeation and absorption to the membrane occurred evenly across all different compound classes and accounted for 40% loss of total aroma compounds. GCO methodology employed the human nose as biological detector to select odor active aroma compounds, describe their odor quality, and determine their odor threshold by a dilution assay. Using PLS regression analysis, the chemical data set (screened according to flavor dilution values determined by GCO) was utilized to model sensory intensities. It was clearly suggested that the lack of fruitiness in