Yield and composition of protein concentrate, press cake, green juice and solubles concentrate from wet fractionation of Sophora japonica, L. foliage

Abstract

A wet-fractionation process was applied to foliage (shoots < 0.5 cm in diameter), twigs, leaves and pods of Sophora japonica L. to obtain press cake and juice or protein concentrate for feeding purposes and, simultaneously, other organic substances for industrial, medical or pharmaceutical use. This paper gives the first results for yields and composition of the original biomass (OB), and of the press cake (PC), green juice (GJ), leaf-protein concentrate (LPC) and soluble concentrate (SC). The dry matter (DM) extraction ratio was 30% in the GJ. From 1000 kg of initial fresh biomass the DM in the LPC was 42 kg and the yield of crude protein (CP) in the LPC reached 6.7 kg. Both OB and PC had high DM contents (32.0 and 31.8% respectively). Neutral detergent fibre (NDF) and acid detergent fibre (ADF) were low (39.0 and 30.8%, respectively) in the DM of PC. Total nitrogen, non-protein nitrogen (NPN), nitric nitrogen and crude ash were 9, 28, 71 and 20% lower, respectively and NDF and ADF were 27% higher, in the PC as compared with the OB dry matter. Relatively high proportions of NDF (6.1%) and ADF (4.4%) were detected in the GJ dry matter, which also had a high content (10.1%) of ether extract (EE). The CP content in the DM of LPC was very low (15.9%). On the other hand, EE (18.0%) and, in particular, total lipids (which amounted to 69% of the DM) were very high. Total carotenoids, carotene and xanthophylls contents in DM of LPC were also low (299.2, 52.1 and 216.6 mg kg −1, respectively); lutein (138.2 mg kg −1) represented more than half of the total xanthophylls. Total polyphenols in the biomass amounted to 11.0% (in LPC 13.6%), these being mainly free polyphenols (9.8 and 12.1%, respectively). Some previous data on the composition of LPC lipidic fractions are also given.