2.4. Mechanical Sieving
Samples were thawed at 4 °C and loaded onto a stack of pre-weighed ultra-sonically cleaned sieves (Endecotts Ltd., London, UK) with the following aperture sizes from top to bottom: 3350, 2000, 1000, 500, 250, 125, 63 and 45 µm, a 20 µm nylon mesh and a sieve base. The sample was washed with deionised water before being placed on a mechanical sieve shaker (Endecotts Ltd., UK) for 15 min to allow the masticated almonds particles to pass through the sieves until they reached the sieve with an aperture size smaller than the size of that particle. Sieves were washed with deionised water to facilitate movement of lodged particles down through the sieve tower. To remove all water, leaving only the masticated almond samples, all sieves were then placed in a forced air oven at 56 °C for 24 h after which each sieve was weighed at 15 min intervals until a constant weight was reached (within 0.1 g). Oven temperature was increased to 80 °C and sieve bases were dried for a further 12 h, after which each sieve was weighed at 15 min intervals until weight was constant.For PSD analysed by mechanical sieving, the proportion of masticated almonds retained on each sieve was expressed as a percentage of the total weight of sample recovered from the sieves (% weight; not including the contents of the sieve base).