Abstract: In this study, cold-pressed peanut meal hydrolysate (also named as cold-pressed peanut meal peptone, CPMP) was prepared by sequential enzymatic hydrolysis using pepsin and alkali proteinase. The molecular mass distribution, proximate analysis and amino acid composition of CPMP were determined. Furthermore, its potential as an alternative to the commercial peptone in microbial culture was evaluated. CPMP was mainly composed of < 5.0 kDa peptide fractions. CPMP was rich in Ala, Arg, Asp, and Cys, especially Glu. Escherichia coli grew better for 8 h in CPMP medium than in beef peptone yeast medium. Bacillus subtilis exhibited a longer lag phase in CPMP medium than in Luria-Bertani medium and possessed a better growth behavior after 8 h incubation. The pH of CPMP medium inoculated with E. coli or B. subtilis displayed no statistically significant difference compared with the control medium (P > 0.05). Lactobacillus casei exhibited a different growth behavior in CPMP medium from that in MRS medium (P < 0.05). Staphylococcus aureus grew well in CPMP medium with no significant difference from the control. Saccharomyces cerevisiae in CPMP showed similar growth behavior and pH trend to those in the control. Aspergillus oryzae grew well in CPMP, similar to that in Czapek-Dox medium. Our evidence demonstrated that CPMP has a good potential as a commercial peptone alternative for microbial growth.

Key words: cold-pressed peanut meal, peptone alternative, synergistic hydrolysis, microbial culture