The effect of air relative humidity on the appearance and structure of subcutaneous pork fat unsalted or treated with NaCl, KCl or K-lactate

This study evaluated the effect of different air relative humidities (RH) and temperatures (T) on the appearance and structure of subcutaneous fat unsalted or treated with NaCl, KCl or K-lactate. Subcutaneous fat samples were stored for 60 days at different RH and T (from 63.5% to 87.7% at 5 °C and from 57.7% to 84.3% at 25 °C). The water content of the subcutaneous fat samples depended on the air RH and T and on the salting treatment. Within each salting treatment, fat samples with lower water contents showed oil drip on the surface, except for samples treated with K-lactate, which did not show oil drip at any RH or T. The air RH below which oil drip appeared depended on the salting treatment. Adipocytes from the external layer of the samples with oil drip showed a wrinkled appearance under the light microscope, which was related to water loss. Hardness of subcutaneous fat decreased with increasing water content in a non-linear way, similar to that described for lean tissue in the literature.

► Effect of air RH and T on subcutaneous fat with NaCl, KCl or K-lactate was studied. ► Samples with lower water contents showed oil drip on the surface for NaCl and KCl. ► The air RH below which oil drip appeared depended on the salting treatment. ► Samples with oil drip showed a wrinkled appearance under the light microscope. ► Hardness of subcutaneous fat decreased with water content in a non-linear way.