Meeting Abstract

88.5  Wednesday, Jan. 7  Food for thought: the effects of roasting and mechanical tenderization on food material properties, masticatory force production and comminution. ZINK (DUNCAN), K.D.*; LIEBERMAN, D.E.; Harvard University; Harvard University kduncan@fas.harvard.edu

Can Homo facial and dental size decreases be attributed to the adoption of food processing techniques? This study experimentally tests the extent to which roasting and mechanical tenderization of meat and root vegetables (tubers) affect food material properties and subsequently masticatory force production and comminution efficiency. The toughness, modulus of elasticity and fracture stress of each food was determined. 15 subjects chewed size-standardized samples of the raw, roasted or mechanically tenderized food. EMG signals from the balancing side masseter were collected and calibrated to masticatory force using a force transducer. Comminution (fragmentation) performance was assessed by measuring the particle size distribution of unswallowed food boluses. Preliminary results suggest that processing affects masticatory performance differently depending on the type of food and processing technique used. Roasting increases meat toughness, modulus of elasticity and masticatory force production, but decreases those same parameters for tubers. Roasting also appears to affect the degree to which meat, but not tubers, are fractured in the oral cavity. Mechanical tenderization of meat does not affect comminution, however subjects chewed these samples less than those that were raw or roasted, resulting in a net decrease of total masticatory force production. Although data regarding the effects of tenderizing tubers still needs to be analyzed, these initial results suggest that food mechanical tenderization may have played an important intermediate step in hominid cranio-dental evolution prior to the advent of cooking.