Use of artichoke (Cynara scolymus) flower extract as a substitute for bovine rennet in the manufacture of Gouda-type cheese: Characterization of aspartic proteases

Berta E Llorente,Walter David Obregón,Francesc X Avilés,Néstor O Caffini,Sandra Vairo-Cavalli

doi:10.1016/j.foodchem.2014.03.007

Berta E Llorente, Walter David Obregón + Show 3 more

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https://doi.org/10.1016/j.foodchem.2014.03.007

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Abstract

Artichoke (Cynara scolymus L.) flower extract was assayed with the aim of replacing animal rennet in the manufacture of Gouda-type cheeses from bovine milk. Floral extract coagulated milk within a suitable time for use on an industrial scale, while the yield of cheese obtained was equal to that achieved with bovine abomasum. Five proteolytic fractions with milk-clotting activity were isolated in a two-step purification protocol, three belonging to the cardosin group. Cheeses made with C. scolymus proteases must be brined for a longer period (40h) to prevent overproteolysis and avoid the development of a background flavor. The type of coagulant (bovine or vegetable) had no significant effect on the cheeses’ chemical parameters analyzed throughout ripening, and no significant organoleptic differences were detected between those manufactured with C. scolymus or animal rennet. The results indicate that C. scolymus flower extract is suitable for replacing animal rennet in the production of Gouda-type cheeses.

Highlights

Cheese is traditionally produced through the use of commercial calf rennet or rennet substitutes as enzymes of microbial origin, recombinant proteases metabolized by genetically modified microorganisms, and plant proteases (Jacob, Jaros, & Rohm, 2011)
Crude extract from fresh flowers of C. scolymus L., exhibited milk-clotting activity
Brutti, Natalucci, and Caffini (1997) originally provided evidence that the curdling activity of extract from the inflorescence of C. scolymus at various stages of development is caused by aspartic peptidases (APs)

Summary

Introduction

Cheese is traditionally produced through the use of commercial calf rennet or rennet substitutes as enzymes of microbial origin, recombinant proteases metabolized by genetically modified microorganisms, and plant proteases (Jacob, Jaros, & Rohm, 2011). Milk has a natural pH of 6.5, while the pH optimum for the hydrolysis of j-casein in the primary phase of rennet coagulation is 5.1–5.3. The primary function of the enzymes in rennets is to destabilize the casein micelle and cause the gelation or coagulation of milk, but those hydrolases play a major role in proteolysis during maturation of cheeses (Lane, Fox, Johnston, & McSweeney, 1997). Substitutes with cheese-making potential should mimic calf rennet specific properties: a high ratio of clotting activity to proteolytic activity at pH and temperature of cheese-making as well as a sufficient thermolability to ensure whey products without remnants of active coagulant (Jacob et al, 2011).

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