Changes in oral processing parameters of three rice varieties

Area of Science:

• Food Science
• Oral Physiology
• Biomechanics

Background:

• Mastication and saliva are crucial for bolus formation and eating enjoyment.
• Detailed studies on oral processing of rice, including physiological parameters and bolus moisture, are lacking.

Purpose of the Study:

• To investigate salivary flow rate, secretion, chewing frequency, and bolus moisture content during oral processing of japonica, indica, and glutinous rice.
• To analyze differences among rice varieties and oral processing stages.

Main Methods:

• Measurement of salivary flow rate and secretion.
• Recording of chewing frequency.
• Analysis of bolus moisture content at different processing stages (25%, 50%, 75%, 100%).
• Comparison of three rice varieties: japonica, indica, and glutinous.

Main Results:

• Swallowing time was significantly lower for glutinous rice compared to japonica and indica rice (p < .05).
• Chewing frequency remained consistent across all rice varieties and stages (1.59–1.66 Hz, p > .05).
• Salivary flow rates significantly decreased during oral processing (37.72 ± 4.32 mg/s to 19.83 ± 5.50 mg/s, p < .05).
• Dry basis bolus moisture content significantly increased (1.53 ± 0.08 to 1.96 ± 0.02, p < .05).
• Saliva secretion in the 75%-100% stage was highest for japonica, followed by indica and glutinous rice (p < .05).
• At swallowing (100% stage), bolus moisture content was consistent across all rice types (1.94–1.99, p > .05).

Conclusions:

• Oral processing of rice involves significant changes in salivary flow and bolus moisture.
• Rice variety influences swallowing time and saliva secretion, but not chewing frequency.
• The final bolus moisture content at swallowing is consistent across different rice varieties.