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Samples of adipose tissue from unsatisfactory, soft, vacuum-packs of rindless bacon rashers were compared with satisfactory harder samples to determine the factors responsible for the difference in consistency. Lipid from unsatisfactory packs contained significantly higher mean concentrations of unsaturated fatty acids, lower mean concentrations of saturated fatty acids and had a lower mean melting point and mean slip point. Discriminant analysis revealed that the samples were best differentiated according to their proportion of linoleic acid or by the ratio of stearic acid to linoleic acid. Linoleic acid was the best discriminator although stearic acid and palmitic acid were correlated best with the melting point and slip point of the lipid and with the force required to puncture the intact adipose tissue by a probe attached to an Instron materials testing machine. Samples which would give satisfactory firm packs, based on the data from discriminant analysis, required a puncture force greater than 7N. In terms of the spectrum of backfat consistency in British pigs, satisfactory bacon comes from hard backfat whereas the unsatisfactory packs come from backfat of medium consistency.

Steer chuck and blade were pre-broken by grinding at --3.0°C and -7.0"C, re-tempered to -3.O"C and -7.0°C, respectively, and then flaked through aperture sizes of 6.1 mm, 9.9 mm or 19.0 mm. Meat was also flaked at -34°C without being pre-broken.More ice melted at the lower temperature; the gain in enthalpy was also higher at -7°C than at -3°C. Size measurements, made using video image analysis, showed that particles produced at the lower temperature had a smaller mean diameter and a greater surface area. Of the three factors investigated, temperature was the most important influence on particle thickness. For a given feed material there was a good correlation between mean diameter and aperture size.High speed photography results showed that pre-broken meat tended to break-up more readily on the impeller than intact pieces, resulting in pieces of smaller mean diameter.