A trial of human electromyography to evaluate texture of softened foodstuffs prepared with freeze-thaw impregnation of macerating enzymes

•Texture properties of softened foodstuffs prepared with FI technique were analyzed.•Electromyography (EMG) was introduced for analysis of oral behaviors.•The bamboo shoot and shiitake mushroom could be eaten with less muscle activity.•Dried fibrous residue was a good indicator for evaluating ease of bolus formation.

Using electromyography (EMG), we studied the changing texture of softened foodstuffs, prepared using a freeze-thaw impregnation of macerating enzymes, by observing eating behavior. EMG recordings were taken from the masseter muscles and suprahyoid musculature of 6 subjects. All five samples (bamboo shoot, burdock root, lotus rhizome, Pacific cod, shiitake mushroom) were softened sufficiently to be broken up with a spoon. The duration of whole oral processing and three variables of interest extracted from the masseter EMGs (total muscle activity, total duration, and cycle time) were significantly different among the samples. Different oral behaviors were observed especially at later processing times. The bamboo shoot and shiitake mushroom required less effort for oral processing compared with the other three samples. The duration of whole oral processing significantly correlated with two instrumental parameters (dried fibrous residue and cohesiveness). Dried fibrous residue was a good indicator for evaluating the ease of bolus formation.Industrial relevanceAn enzymatic application using the freeze-thaw impregnation technique has been established for developing softened foods. The food products have a softness that allows crushing with the tongue and upper jaw while retaining the original characteristics of shape and flavor. Such food products have not been previously manufactured; the evaluation of texture properties by a human is indispensable information. The information can be used in controlling the quality of the softened products by manufacturers and in choosing the preferred products by consumers.