Artichoke cv. Francés flower extract as a rennet substitute: effect on textural, microstructural, microbiological, antioxidant properties, and sensory acceptance of miniature cheeses.

BACKGROUND: The most common milk-clotting enzymes in the cheese industry are recombinant chymosins. Food naturalness is a factor underpinning consumers' food choice. For consumers who avoid food with ingredients from genetically modified organisms (GMOs), the use of vegetable-based rennet substitute in the cheese formulation may be a suitable solution. Artichokes that deviate from optimal products, when allowed to bloom due to flower protease composition, are excellent as raw material for vegetable rennet preparation. As enzymatic milk clotting exerts a significant impact on the characteristics of the final product, this product should be studied carefully. RESULTS: Mature flowers from unharvested artichokes (Cynara scolymus cv. Francés) that did not meet aesthetic standards for commercialization were collected and used to prepare a flower extract. This extract, as a coagulant preparation, enabled the manufacture of cheeses with distinctive characteristics compared with cheeses prepared with chymosin. Rennet substitution did not affect the actual yield but led to significant changes in dry matter yield, humidity, water activity, protein content, and color, and conferred antioxidant activity to the cheeses. The rennet substitution promoted significant modifications in springiness, and in the microstructure of the cheese, with a more porous protein matrix and an increment in the size of the fat globules. Both formulations showed a similar microbiota evolution pattern with excellent microbiological quality and good sensory acceptance. CONCLUSIONS: The rennet substitute studied here produced a cheese adapted to specific market segments that demand more natural and healthier products made with a commitment to the environment but well accepted by a general cheese consumer. © 2020 Society of Chemical Industry.

Miniature cheeses made with blends of chymosin and a vegetable rennet from flowers of Silybum marianum: Enzymatic characterization of the flower-coagulant peptidase.

Binary blends of S. marianum-flower extract and chymosin, as coagulant preparations, enabled the manufacture of miniature cheeses with distinctive characteristics compared to those of chymosin-renneted cheeses. The physicochemical parameters, sensory attributes of the cheeses, and in-vitro water-soluble antioxidant activity were analyzed and compared to those properties obtained from control chymosin-renneted cheeses. The preponderant proteolytic constituent in the flower extract was isolated in a two-step-purification protocol. The thus purified aspartic peptidase was maximally active at acidic pHs and exhibited a preference for peptide bonds between hydrophobic residues. Enzymologic characterization revealed differences in the kinetic parameters and specificity compared to other enzymes employed, such as rennet. S. marianum-flower extract, as a source of peptidase with distinctive characteristics, is a suitable substitute for chymosin in miniature-cheese production. The addition of vegetable rennet contributed to the development of an intense aroma and conferred antioxidant activity to the cheeses and wheys.