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Modulation of coffee flavor precursors by Aspergillus oryzae serine carboxypeptidases.

Pushpa, S. Murthy and Sneha, H. P. and Basavaraj, K. and Kusumotoc, Ken-Ichi (2019) Modulation of coffee flavor precursors by Aspergillus oryzae serine carboxypeptidases. LWT - Food Science and Technology, 113. pp. 1-12.

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Abstract

Aspergillus oryzae was isolated from coffee pulp, screened for the production of carboxypeptidase and confirmed by molecular studies. Coffee pulp posses high protease activity (1.4×103 nkat/mL) among the agro-substrates used for the production of proteases but wheat bran was used for further studies considering its easy availability in large volumes. Proximal composition, pre-treatment, auxiliary carbon and nitrogen with growth studies indicated carboxypeptidase activity (2.6×103 nkat/g). The RSM was employed to generate a predictive model of the combined effects of independent variables and indicated a significant impact on acid carboxypeptidase with 35% moisture, 30 °C temperature, 108 CFU mL−1 inoculum and 100 h duration with 4.8×103 nkat/g activity. The partially purified peptidase had a specific activity of 6.1×104 nkat/mg with a molecular weight of 50 kDa, optimal pH 3.6, temperature 35 °C and feature of a serine protease. Enzyme stability was maintained with 50% glycerol and 2 mg/mL BSA. The protease application to develop flavor profiles of coffee was noteworthy with an organoleptic score of 7.5 compared to 4.5 of the untreated sample. GC-MS highlighted enhanced flavor annotations of pyrazines contributing sweet fruit notes. Carboxypeptidase augmented the coffee bean with specialized flavor notes and has been reported for the first time.

Item Type: Article
Uncontrolled Keywords: Acid carboxypeptidase Aspergillus oryzae Growth studies Solid-state fermentation Purification Coffee
Subjects: 600 Technology > 07 Beverage Technology > 04 Coffee
600 Technology > 08 Food technology > 15 Flavour/Fragrance/Perfumes
Divisions: Plantation Products Spices and Flavour Technology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 22 Jul 2019 04:42
Last Modified: 22 Jul 2019 04:42
URI: http://ir.cftri.res.in/id/eprint/14206

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