Clotting Properties of Onopordum tauricum (Willd.) Aqueous Extract in Milk of Different Species

Abstract

Plant proteases used in cheesemaking are easily available and could increase the acceptability of cheeses, otherwise hindered by ethical issues (e.g., religions, dietary habits, aversion to genetically engineered food and food ingredients). The milk clotting potential of Onopordum tauricum (Willd.) aqueous extract as an alternative to animal rennet was assessed for the first time in milk of different species (ewe, goat, cow). Among the aerial anatomical parts, i.e., receptacle, leaves, stems, and flowers, only the latter ones showed clotting properties. A response surface methodology (RSM) was used to explore the effects of three independent variables (temperature, pH, volume of coagulant) on the milk clotting activity (MCA) of the flower extract. A second-order polynomial model adequately described the experimental data and predicted a temperature value of 55 °C, a pH value of 4.9–5.7, and a volume of coagulant of 300–500 μL (added to 5 mL of milk) as optimal conditions to maximize the MCA. At a 35 °C temperature and natural milk pH of 6.7–6.8, the estimated MCA of the O. tauricum extract was 72–87, 69–86, and 75–151, in goat’s, ewe’s, and cow’s milk, respectively. In comparison, the MCA of calf rennet was 5.4–4.9, 3.3–14.7, and 4.9–16.7 times higher than that of the plant extract in goat’s, ewe’s, and cow’s milk, respectively.

Microbial communities and volatile profile of Queijo de Azeitão PDO cheese, a traditional Mediterranean thistle-curdled cheese from Portugal

“…Afterwards, the SPME fiber (divinylbenzene/carboxen/polydimethylsiloxane, 1 cm, 50/30 µm) from Supelco/Sigma-Aldrich (Milan, Italy) was exposed into the headspace for 10 min. Volatile profile was analyzed and identified according to Mozzon et al (2020).…”

Effect of Planting Density in Two Thistle Species Used for Vegetable Rennet Production in Marginal Mediterranean Areas

“…Tubular flowers of O. tauricum Willd. need to be macerated in demineralized water (1:10 w/v) for 24 h at 4 • C. The aqueous crude extract is freeze-dried and reconstituted in demineralized water 1:10 w/v [11]. Further research, not published yet, shows that 20 mL of reconstituted extract is necessary to clot 5 L of ewes' milk with the addition of CaCl 2 solution (10 mM), obtaining a yield of around 50%.…”

“…require little additional irrigation because they are well adapted to the xerothermic conditions of southern Europe, which is characterized by dry and hot summers [6,7]. Their adaptation to southern European environmental conditions and their high yield suggests that these species could be useful for industrial [3,[8][9][10], technological food [11] and pharmacological [12][13][14] use.…”

“…The flowers of wild cardoon are traditionally used as a milk-clotting agent to produce cheeses in countries such as Portugal, Spain, Morocco, and Italy [24]. The use of vegetable rennet is geographically circumscribed and limited to a few products, but the scarcity and high price of conventional animal rennet has led to a growing interest in the vegetable sources of milk-clotting enzymes [11].…”

Microbial Dynamics of a Specialty Italian Raw Ewe’s Milk Cheese Curdled with Extracts from Spontaneous and Cultivated Onopordum tauricum Willd

“…Very recently, Onopordum tauricum Willd. has been deeply investigated for its curdling properties towards ewe’s, goat’s, and cow’s milk [ 24 , 25 ]. Native to Southern Europe and Southwestern Asia, this thistle grows spontaneously in Italy, especially in marginal areas of Central and Southern regions [ 26 ].…”