Cheesemaking with vegetable rennet (O. tauricum): evaluation of fatty acid composition and volatile profile.

Actually, plant coagulants offer an alternative to the calf rennets conciliating religious factors, diet or ban on recombinant calf rennet in some countries and answering issues due to the scarce availability causing the price increase on the market. Therefore, plant tissues are sources of enzymes essential to the cheesemaking process that can be obtained from their natural source or through in vitro culture to guarantee a continuous stream of plant proteases. Although most of the enzymes used as milk coagulants belong to the aspartic proteases, enzymes from other groups such as cysteine and serine protease have been reported as possessing the ability to coagulate milk under suitable conditions. Lower yields of cheese, bitter flavors and consistency imperfections are however defects due to the excessive proteolytic nature of most vegetable coagulants, limiting their use in the production of cheeses; this pushes the search for new potential rennets for the coagulation of milk from plants to meet the growing world demand. Therefore, the growing global demand for cheese coupled with the reduced supply of calf rennet made necessary to select a suitable vegetable coagulant. The selection of an appropriate substitute for calf rennet requires a thorough study of the technological properties; this entails analyses relating to milk coagulation activity (MCA) and proteolytic activity (PA) which are considered crucial steps in the study since the activities’ ratio impacts the rheological and sensorial properties of the produced cheeses. An excellent product with desirable firmness and no release of the typical bitter aromas of plant proteases is generally achieved when a high value of this ratio is obtained. Therefore, the study of the enzymatic and technological properties of vegetable rennet, previously analysed in the literature, provides a clear overview of the key elements for the choice of the appropriate vegetable rennet. Consistent with what has been said, the examination and evaluation of the diverse physio-chemical properties of cheeses obtained with plant proteases are the primary aim of this study. Types and sources of diverse plant proteases involved in milk coagulation are discussed and particular attention is given to plant extract of Onopordum tauricum whose chemical, technological and coagulant properties are analysed. Onopordum tauricum extract’s functional properties and enzymatic role in cheese production are evaluated. The cheese under analysis is produced in the Marche foothills and is characterized by the use of local spontaneous flora of Onopordum tauricum used for the preparation of aqueous extracts used as milk coagulant. Specifically, fatty acids composition and volatile profile of cheeses obtained with Onopordum tauricum enzyme preparation are object of laboratory’s studies carried out in the Department of the Università Politecnica delle Marche. In addition, effects of plant coagulants on rheological properties of gels and influencing factors are explored. Examples of cheeses available on market are reported. Lastly, a general analysis on the designation of origin that provide for the use of vegetable rennet in the European context is proposed. Finally, considerations and conclusion are provided on the bases of the scientific literature available, and the laboratory’s activities. Finally, considerations and conclusion are provided on the bases of the scientific literature available, and the laboratory’s activities.

Actually, plant coagulants offer an alternative to the calf rennets conciliating religious factors, diet or ban on recombinant calf rennet in some countries and answering issues due to the scarce availability causing the price increase on the market. Therefore, plant tissues are sources of enzymes essential to the cheesemaking process that can be obtained from their natural source or through in vitro culture to guarantee a continuous stream of plant proteases. Although most of the enzymes used as milk coagulants belong to the aspartic proteases, enzymes from other groups such as cysteine and serine protease have been reported as possessing the ability to coagulate milk under suitable conditions. Lower yields of cheese, bitter flavors and consistency imperfections are however defects due to the excessive proteolytic nature of most vegetable coagulants, limiting their use in the production of cheeses; this pushes the search for new potential rennets for the coagulation of milk from plants to meet the growing world demand. Therefore, the growing global demand for cheese coupled with the reduced supply of calf rennet made necessary to select a suitable vegetable coagulant. The selection of an appropriate substitute for calf rennet requires a thorough study of the technological properties; this entails analyses relating to milk coagulation activity (MCA) and proteolytic activity (PA) which are considered crucial steps in the study since the activities’ ratio impacts the rheological and sensorial properties of the produced cheeses. An excellent product with desirable firmness and no release of the typical bitter aromas of plant proteases is generally achieved when a high value of this ratio is obtained. Therefore, the study of the enzymatic and technological properties of vegetable rennet, previously analysed in the literature, provides a clear overview of the key elements for the choice of the appropriate vegetable rennet. Consistent with what has been said, the examination and evaluation of the diverse physio-chemical properties of cheeses obtained with plant proteases are the primary aim of this study. Types and sources of diverse plant proteases involved in milk coagulation are discussed and particular attention is given to plant extract of Onopordum tauricum whose chemical, technological and coagulant properties are analysed. Onopordum tauricum extract’s functional properties and enzymatic role in cheese production are evaluated. The cheese under analysis is produced in the Marche foothills and is characterized by the use of local spontaneous flora of Onopordum tauricum used for the preparation of aqueous extracts used as milk coagulant. Specifically, fatty acids composition and volatile profile of cheeses obtained with Onopordum tauricum enzyme preparation are object of laboratory’s studies carried out in the Department of the Università Politecnica delle Marche. In addition, effects of plant coagulants on rheological properties of gels and influencing factors are explored. Examples of cheeses available on market are reported. Lastly, a general analysis on the designation of origin that provide for the use of vegetable rennet in the European context is proposed. Finally, considerations and conclusion are provided on the bases of the scientific literature available, and the laboratory’s activities