doi: 10.17113/ftb.55.03.17.5040 

Production of Hypoallergenic Antibacterial Peptides from Defatted Soybean Meal in Membrane Bioreactor: A Bioprocess Engineering Study with Comprehensive Product Characterization

Arijit Nath¹, Gábor Szécsi¹, Barbara Csehi², Zsuzsa Mednyánszky³, Gabriella Kiskó⁴, Éva Bányai⁵, Mihály Dernovics⁵ and András Koris¹*

¹Department of Food Engineering, Faculty of Food Science, Szent István University, Ménesi st 44, HU-1118 Budapest,
  Hungary
²Department of Refrigeration and Livestock Product Technology, Faculty of Food Science, Szent István University, Ménesi st
  43–45, HU-1118 Budapest, Hungary
³Department of Food Chemistry and Nutrition, Faculty of Food Science, Szent István University, Budapest, Somlói st 14–16,
  HU-1118 Budapest, Hungary
⁴Department of Food Microbiology and Biotechnology, Faculty of Food Science, Szent István University, Budapest, Somlói st
  14–16, HU-1118 Budapest, Hungary
⁵Department of Applied Chemistry, Faculty of Food Science, Szent István University, Budapest, Villányi st 29–33, HU-1118
  Budapest, Hungary

Article history:
Received: October 28, 2016
Accepted: May 19, 2017

Key words:
soybean meal, enzymatic hydrolysis, peptide separation, low-molecular-mass antibacterial peptides

Summary:
Hypoallergenic antibacterial low-molecular-mass peptides were produced from defatted soybean meal in a membrane bioreactor. In the first step, soybean meal proteins were digested with trypsin in the bioreactor, operated in batch mode. For the tryptic digestion of soybean meal protein, optimum initial soybean meal concentration of 75 g/L, temperature of 40 °C and pH=9.0 were determined. After enzymatic digestion, low-molecular-mass peptides were purified with cross-flow flat sheet membrane (pore size 100 μm) and then with tubular ceramic ultrafiltration membrane (molecular mass cut-off 5 kDa). Effects of transmembrane pressure and the use of a static turbulence promoter to reduce the concentration polarization near the ultrafiltration membrane surface were examined and their positive effects were proven. For the filtration with ultrafiltration membrane, transmembrane pressure of 3·10⁵ Pa with 3-stage discontinuous diafiltration was found optimal. The molecular mass distribution of purified peptides using ultrafiltration membrane was determined by a liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry setup. More than 96 % of the peptides (calculated as relative frequency) from the ultrafiltration membrane permeate had the molecular mass M≤1.7 kDa and the highest molecular mass was found to be 3.1 kDa. The decrease of allergenic property due to the tryptic digestion and membrane filtration was determined by an enzyme-linked immunosorbent assay and it was found to exceed 99.9 %. It was also found that the peptides purified in the ultrafiltration membrane promoted the growth of Pediococcus acidilactici HA6111-2 and they possessed antibacterial activity against Bacillus cereus.

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