Oral movements and the perception of semi-solid foods.

Here we review the role of oral movements in the perception of food attributes, particularly for semi-solid and liquid foods ingested almost in ready-to-swallow form. An overview of a series of instrumental and sensory studies suggests clear links between the type of sensation and the time point of processing in the mouth. Some commonly-reported sensations, such as thickness, are relatively immediate and reflect the bulk properties of food bolus when the food is relatively intact.

Vibromyography of oral processing varies with type of semi-solid food and with sensory judgements.

Vibromyography was used to quantify oral activity during the processing of well-characterized semi-solid model foods whilst subjects assessed the intensity of the sensory attributes to thick, creamy, melting, fatty, rough and liking. A series of eleven starch-based vanilla custard desserts was prepared with five different viscosities, three different fat levels, and three different particle sizes. Over 5 sessions, subjects (N=10) took 5 ml spoonfuls of each of the stimuli for 5 s before they rated the strength of the various attributes.

The effect of saliva composition on texture perception of semi-solids.

Saliva is expected to be of significance for the perception of food stimuli in the mouth. Mixing the food with saliva, including breakdown and dilution, is considered to be of large importance for semi-solids as these products are masticated without chewing. It is known that there are large variations in composition of saliva originating from different glands and different subjects.

Oral processing assessed by M-mode ultrasound imaging varies with food attribute.

Ultrasonic imaging was used to quantify oral movements made during the oral processing of foods while subjects assessed the intensity of the sensory attributes, thick, creamy, sweet and bitter. A series of four stimuli were prepared with high and low viscosities and high and low sweetness. Over five sessions, subjects (N=8) were asked to consume 5 ml spoonfuls of each of the stimuli while holding an ultrasound probe beneath their chin so as to produce a mid-line sagital image of the floor of the mouth and tongue.

Relating particles and texture perception.

Practically all foods contain particles. It has been suggested that the presence of particles in food may affect the perception of sensory attributes. In the present study we investigated the effect of size and type (hardness and shape) of particles added to a CMC based vanilla custard dessert.

The role of alpha-amylase in the perception of oral texture and flavour in custards.

The role of salivary alpha-amylase in odour, flavour, and oral texture sensations was investigated in two studies in which the activity of salivary amylase present in the mouth of human subjects was either increased by presenting custards with added alpha-amylase or decreased by presenting custards with added acarbose, an amylase inhibitor. For starch-based vanilla custard desserts, amylase resulted in increased melting and decreased thickness sensations, whereas acarbose had the opposite effect, i.e.

Amount of ingested custard dessert as affected by its color, odor, and texture.

The effects of nonoral sensations, such as visual texture and odor, on the size of the first bite were investigated in a series of studies using specially constructed food delivery cups with lower, from which custards were ingested ("ingested custard"), and upper, from which a custard was viewed and/or smelled ("upper custard") compartments. Ingested and upper custards were either the same or different. Bite size was defined as the weight of custard sucked out of the lower compartment during a single suck through an 11-mm diameter straw.

Clinical criteria used to detect primary root caries with electrical and mechanical measurements in vitro.

Purpose: To relate the Electrical Caries Monitor (ECM) and Resilience Caries Monitor (RCM) readings with clinical criteria used to define primary root carious lesions (PRCLs) in vitro.

Methods: PRCLs were classified according to color, texture, hardness, cavitation, size and severity before ECM and RCM readings were recorded.

Results: There was a poor but significant correlation between the ECM and RCM phase readings (P < 0.

The effect of oral and product temperature on the perception of flavor and texture attributes of semi-solids.

This study examined the effect of oral and product temperature on the perception of texture and flavor attributes. A trained panel assessed 21 texture and flavor attributes in one high-fat and one low-fat product of two semi-solids: custard dessert and mayonnaise. The products were evaluated at 10, 22 or 35 degrees C in combination with oral temperatures of 27, 35 and 43 degrees C.

NaCl and sugar release, salivation and taste during mastication of salted chewing gum.

Salt perception impacts on food acceptability and nutrition and depends upon salt release from foods that was determined in situ during mastication of chewing gum with up to 10% (1800 mmol/kg) added NaCl. The mechanical action of chewing increased salivation, which was further increased by the presence of salt, particularly above 180 mmol NaCl/kg gum or above 100 mM NaCl in saliva. The average resting salivary flow rate was 1 ml/min, increasing to 4 and 6 ml/min with gums containing low and high salt, respectively.

A comparison of the effects of added saliva, alpha-amylase and water on texture perception in semisolids.

The effect of adding saliva or a saliva-related fluid (alpha-amylase solution and water) to custard prior to ingestion on the sensory ratings of odour, flavour and lip-tooth-, mouth- and after-feel sensations was investigated. Saliva had previously been collected from the subjects and each subject received his/her own saliva. Sixteen subjects from a trained panel assessed 17 flavour and texture attributes of soy- and milk-based custard desserts.

The role of intra-oral manipulation in the perception of sensory attributes.

To gain insight into the effect of oral processes on perception, we defined a set of five specific oral manipulations and investigated their effects on the perception of low and high fat versions of two semi-solid foodstuffs, vanilla custard desserts and mayonnaises. Behavior modifications ranged from simply placing the stimulus on the tip of the tongue to vigorously moving it around in the mouth. Sensory ratings for mouth-feel and flavor attributes were made 5s after placing the stimulus in the mouth, and after-feel attributes were rated immediately after swallowing.

The relation between saliva flow after different stimulations and the perception of flavor and texture attributes in custard desserts.

Salivary flow rates were measured at rest and after three types of stimulation; odor, Parafilm chewing, and citric acid. The highest flow rate was elicited by citric acid followed by Parafilm and odor, while the lowest flow rate was unstimulated. In order to investigate whether and how the amount of saliva a subject produces influences the sensory ratings, the four types of salivary flow rates were correlated with sensory ratings of three different types of vanilla custard dessert.

The effect of oral temperature on the temperature perception of liquids and semisolids in the mouth.

This work examined the influence of oral temperature on oral perception of temperature in liquids and semisolids. A panel of 20 adults assessed the temperature of water, custard dessert and mayonnaise. Oral temperatures were manipulated by 5-s mouth rinses of 10, 35 and 55 degrees C performed prior to assessments, which resulted in oral temperatures of 27, 35 and 43 degrees C, respectively.