Comparative study of the chemical composition and nutritional value of pumpkin seed cake, soybean meal and casein

The chemical composition and nutritional value of pumpkin (Cururbita pepo) seed cake (PSC) were studied and compared with those of casein and soybean meal. Crude protein and ether extract content in dry matter of PSC was 598. 0 g/kg and 124.6 g/kg, respectively, and was higher than the percentage of these components (474.2 and 28.3 g/kg, respectively) in soybean meal used i n this experiment. The main fatty acids in PSC cake were oleic acid (50.4%) and linoleic acid (29.9%). Protein found in PSC contained considerable qua ntities of tryptophan (1.54 g/16 g N); by contrast, the content of lysine ( 3.21 g/16 g N) and isoleucine (3.83 g/16 g N) was low. Small quantities of phenolic compounds (2.61 g/kg), low activity of trypsin inhibitors (1.33 TU I/mg) and small quantities of alpha-galactosides (19.9 g/kg) were found in PSC. Among antinutritive components only the content of inositol phosphates in PSC (40.5 mg/g) was higher than in soybean meal (10.8 mg/g). True diges tibility coefficient (TD) of PSC protein was similar (83.1%), but protein e fficiency ratio (PER) was lower(1.01) in comparison with soybean meal (83.5 % and 1.50, respectively). After supplementation with lysine, TD (85.9%) an d PER (1.43) in PSC were comparable with TD and PER to soybean meal. The PS C-soybean meal mix diet (protein ratio 1:1)had a higher PER value than the diet with soybean meal only (1.98 vs. 1.50).