Amelioration of cocoa organoleptics using A.oryzae cysteine proteases

P. Murthy,Sneha Hassan Palakshappa,Janardhan Padela,K. Kusumoto

Published 2020 in Lwt - Food Science and Technology

ABSTRACT

Abstract The A.oryzae strains isolated from coffee were screened to evaluate their potential for production of acid aspartic protease. The strains with highest activity were then subjected to UV-mutagenesis and the lethality was determined by spore spread plate method. The mutant strain CPO 025 produced 1.3 × 104 U/ml, which is 1.53 fold higher than the parent with survival rate of 76 ± 2%. The Central Composite Rotatable Design(CCRD) based Response Surface Methodology(RSM) was employed to optimize the parameters for Aspartic protease production. The mutant strain subjected to solid-state fermentation (SSF) using wheat bran as substrate yielded 1820 U/mg specific activity with functional conditions of moisture (35%), inoculum (6.5 CFU/ml), fermentation duration (108 h), and temperature (28 °C). The partially purified proteases by DEAE-Sepharose had attributes with 6082 U/mg specific activity, optimum pH 3.6, temperature 35 °C and MW of 35 kDa. Enhanced activity by β-mercaptoethanol and inhibition by iodoacetic acid confirmed cysteine protease. Application of cysteine protease with cocoa beans upsurged flavour profile compared to the untreated beans. The elevated level of dimethylpyzarine and ketone3,5-Bis(tert-butyl)-4-hydroxy-propiophenone indicated efficient protein hydrolysis with desirable cocoa flavour. Thus cocoa organoleptic enhancement with flavourzyme can camouflage poorly fermented cocoa and economy of the industry.

PUBLICATION RECORD

  • Publication year

    2020

  • Venue

    Lwt - Food Science and Technology

  • Publication date

    2020-02-01

  • Fields of study

    Agricultural and Food Sciences, Chemistry, Environmental Science

  • Identifiers
  • External record

    Open on Semantic Scholar

  • Source metadata

    Semantic Scholar

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REFERENCES

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