2.3. Collection of Mastication Samples
pain
Incomplete dentition, presence of dentures/false teeth and/or recent dental treatment were considered as confounding factors that may impact (1) normal masticatory behaviour due to pain or discomfort in part of the mouth or (2) particle recovery due to lodgement of particles in oral crevices. These data were collected from participants prior to study visit.Whole and ground almonds were provided by the Almond Board of California. To facilitate consumption, ground almonds were mixed with water to form a paste prior to mastication (2.7 mL water was added to each 5 g aliquot of ground almond). In order to record the number of mastication cycles taken by each participant, mastication and swallowing were observed separately for each almond form prior to sample collection. Briefly, participants brushed their teeth before chewing two aliquots of each test food (either whole or ground almonds; random order; 5 g per aliquot) under the observation of a study researcher who counted the number of mastication cycles (chews) taken prior to swallowing. Mean number of mastication cycles for each almond form was calculated.During the mastication experiment, participants were asked to chew (for the mean number of cycles calculated previously) three pre-weighed aliquots of either whole or ground almonds (approx. 5 g each) and without swallowing any almond were asked to expectorate all aliquots into the same pre-weighed beaker fitted with a 20 μm nylon mesh. Participants rinsed their mouth with 25 mL water after each aliquot and expectorated into the same beaker to maximise recovery of almond particles from the mouth. Participants brushed their teeth once again and the session was repeated for the second test food.Beakers were allowed to stand for 20 min to allow saliva and rinse water to pass through the 20 μm nylon mesh. The nylon mesh was inserted into a falcon tube, and centrifuged at 400× 