The effects of soybean press cake on Parma ham quality

Despite of a lack of specific recent literature, press cakes (mechanical extraction) are not presently allowed in PDO (Protected Designation of Origin) hams production due to possible negative effects on fat stability during seasoning tied to their high linoleic acid content. On the other hand, press cakes probably represent the more feasible way to fulfill the amino acidic requirements of pigs raised according to the Organic Method (2). The present trial was aimed to give more insights on the possibility of totally replacing soybean solvent‐extracted meal with soybean cake in the diets of heavy pigs intended for Parma Ham production. Sixty crossbred pigs (initial BW 26 kg) were offered two isoenergetic and isoaminoacidic diets: a control group was fed a diet containing soybean meal (SBM), treatment group received a diet containing soybean cake (SBC). Pigs were slaughtered at 160 kg BW. Right thighs were followed during the whole dry‐curing process (18 months)to calculate weight losses for each productive step. 32 hams (16 for each group) were sensorially evaluated by a panel of five trained experts. Samples of Biceps femoris muscle were analyzed for moisture, crude protein, NaCl and proteolysis index. Fatty acids composition, peroxides and TBARS were assessed in subcutaneous fat. The experimental data obtained were submitted to analysis of variance with the diet assumed as the main effect. No significant differences (P>0.05) were observed during the whole dry‐curing period with respect to ham weight losses. Sensory analysis didn’t reveal any significant difference between the experimental groups with respect both to the lean fraction (humidity, texture, marbling) and the subcutaneous fat (thickness and texture). Chemical analyses showed a significant (P<0.05) reduction in the proteolysis index in the group receiving the SBC diet. However, all chemical parameters fell within the range imposed by Parma Ham (1). The acidic composition of the subcutaneous fat from the dry‐cured hams showed a significant (P<0.01) increase in PUFA and a reduction in SFA and MUFA in the SBC group compared with the SBM group. Such a modification reflects the acidic composition of the diets and that of fat from the raw thighs.However, the overall oxidative stability (peroxides and TBARS) didn’t differ significantly between the groups. Our results suggest that the total replacement of soybean meal (solvent‐extracted) by soybean cake (mechanically‐extracted)does not modify either the main chemical and sensorial traits or the oxidative stability of cured hams. Therefore, such a replacement appears to be a feasible means to achieve entirely organic diets for heavy pigs without compromising PDO hams quality.