Search Results (8)

Consumer interest in vegetarian, ethical, and clean-label foods is reviving the use of plant-derived milk coagulants. Cardosins from Cynara cardunculus (“thistle”) are aspartic proteases with strong clotting activity, yet their technological impact in cheese remains under-explored. This study compared a commercial thistle extract (PC) with traditional bovine rennet rich in chymosin (AC) during manufacture and 60-day ripening of Caciotta cheese. Classical compositional assays (ripening index, texture profile, color, solubility) were integrated with scanning electron microscopy, three-dimensional surface reconstruction, and descriptive sensory analysis. AC cheeses displayed slower but sustained proteolysis, yielding a higher and more linear ripening index, softer body, greater solubility, and brighter, more yellow appearance. Imaging revealed a continuous protein matrix with uniformly distributed, larger pores, consistent with a dairy-like sensory profile dominated by milky and umami notes. Conversely, PC cheeses underwent rapid early proteolysis that plateaued, producing firmer, chewier curds with lower solubility and darker color. Micrographs showed a fragmented matrix with smaller, heterogeneous pores; sensory evaluation highlighted vegetal, bitter, and astringent attributes. The data demonstrate that thistle coagulant can successfully replace animal rennet but generates cheeses with distinct structural and sensory fingerprints. The optimization of process parameters is therefore required when targeting specific product styles. Full article

Onopordum nervosum subsp. platylepis Murb. is an Asteraceae species found in Tunisia, Algeria, and Libya. It has been studied for its potential use as a vegetable rennet alternative to animal-derived rennet, making it important to understand its germination characteristics. This species often shows low germinability due to dormancy, which limits its large-scale cultivation. In preliminary experiments, many factors were analyzed to evaluate the seed germination of this thistle including physical stratification with abrasive paper and high-temperature water, chemical treatments with hydrogen peroxide (H₂O₂) or sulfuric acid (H₂SO₄), and the exogenous use of the growth regulator gibberellic acid (GA₃). Based on the obtained results and subsequent analysis, GA₃ and cold stratification durations were selected for the second experiment, which used a full factorial RSM design with three levels for each factor. Additionally, the total polyphenol content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), and DPPH assay were analyzed during the optimization process and for ungerminated seeds. The findings revealed that 14 days of cold stratification followed by 750 ppm GA₃ was the most efficient method for breaking the dormancy of these thistle seeds. The highest TPC was recorded in ungerminated seeds. However, germinated Onopordum nervosum ssp. platylepis seeds showed higher levels of TFC and CTC (14.83 mg QE/g DW and 6.49 mg EC/g DW, respectively) compared to the non-germinated ones and demonstrated the greatest potency in inhibiting free radicals (DPPH EC₅₀ = 0.018 mg/mL) at the identified optimal germination conditions. Ungerminated seeds indicated significant phenolic content (TPC) and a limited ability to reduce oxidants, which could explain their low germination percentage. Our findings on the seed germination and dormancy characteristics of this endemic thistle will aid in the protection and development of its germplasm. Full article

Cheese production is an ancient practice to preserve a perishable food, such as milk, for a long time. The first step of cheese processing involves the addition of rennet, which contains the enzymes necessary for the hydrolysis and coagulation of the caseins present in milk. Typically, animal-derived rennet, such as calf rennet containing chymosin, are used as source of enzymes for cheese processing. Alternatively, microbial chymosin or recombinant chymosin is used. However, recently, plant-derived rennet such as the ones derived from thistle and bitter orange flowers and from artichoke (Cynara cardunculus var. scolymus) have also been demonstrated to be valid sources of enzymes for cheese processing. Therefore, herein, different plant and fruit extracts were tested and compared for their ability to coagulate milk caseins. In particular, beyond artichoke and cardoon (Cynara cardunculus) extracts, those from pineapple (Ananas comosus (L.) Merr.), papaya (Carica papaya L.), common fig (Ficus carica L.) milky sap, and oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm.) were investigated for their proteolytic, esterase, and milk-clotting activities. The extracts were then exploited as vegetable and fruit rennet for the experimental production of cheeses, which were examined, after 30 days of maturation, for their moisture, fat, protein, and free fatty acid (FFA) content. Interestingly, the artichoke, cardoon, and thistle mushroom extracts showed high proteolytic activity compared to calf rennet, while the level of esterase activity appeared to be similar for all the extracts. The papaya extract showed the lowest proteolytic and esterase activity. Although the pH, moisture, fat, and protein contents were very similar to those of cheese made with calf rennet, the medium- and long-chain FFAs broadly differed among produced cheeses, with variations in the lipid quality indices. Full article

Onopordum tauricum Willd., a species distributed in Eastern Europe, has been the subject of various research endeavors aimed at assessing its suitability for extracting vegetable rennet for use in the production of local cheeses as a substitute for animal-derived rennet. In Italy, the species has an extremely fragmented and localized distribution in six locations scattered across the central-northern Apennines and some areas of southern Italy. In this study, both the morphology and genetic diversity of the six known Italian populations were investigated to detect putative ecotypes. To this end, 33 morphological traits were considered for morphometric measurements, while genetic analysis was conducted on the entire genome using the ddRAD-Seq method. Both analyses revealed significant differences among the Apennine populations (SOL, COL, and VIS) and those from southern Italy (ROT, PES, and LEC). Specifically, the southern Italian populations appear to deviate significantly in some characteristics from the typical form of the species. Therefore, its attribution to O. tauricum is currently uncertain, and further genetic and morphological analyses are underway to ascertain its systematic placement within the genus Onopordum. Full article

Milk coagulation is a process used for the formulation of different dairy products such as cheese. In this process, milk undergoes changes in its chemical stability thanks to acidification or enzymatic reactions. Traditionally, milk coagulation has been carried out with rennet of animal origin, but recently, the research of new types of rennet such as microbial rennet and vegetable rennet has increased. This study aims to present an organized review of the most relevant information on lactic coagulation, its relationship with vegetable rennets, and the importance of the botanical genus Cynara in the extraction of vegetable rennets, focusing on the coagulant potential of artichoke (Cynara scolymus). We conducted this literature review and found that lactic coagulation and vegetable rennets are linked through the enzymatic activity of the latter. The results of the main studies demonstrated a strong relationship between vegetable rennets and protease enzymes as well as the presence of these enzymes in extracts of cardoon (Cynara scolymus) and artichoke (Cynara scolymus). In addition, studies highlight the presence of thistle extracts in artisanal cheese preparations in the Iberian Peninsula. Based on the results of the studies, a comparison between cheeses made with vegetable rennet and those made with traditional rennet was also carried out. Although the results show that the use of vegetable rennet in the manufacture of cheese can confer undesirable characteristics, the use of extracts from Cynara plants demonstrates that vegetable rennets have an industrial potential, especially the one obtained from artichoke (Cynara scolymus) due to its high availability. Nevertheless, specific studies are required for a better understanding and application of this rennet. Full article

Milk coagulants prepared by maceration of flowers harvested from both spontaneous and cultivated Onopordum tauricum Willd. and a commercially available coagulant obtained from Cynara cardunculus L. (control) were assayed for small-scale manufacturing of Caciofiore, an Italian specialty raw ewe’s milk cheese produced in a family run dairy farm located in the Marche region (Central Italy). The microbiota of the three thistle-based milk coagulants and their effect on the microbial dynamics of raw milk cheeses during fermentation and maturation (from day 0 up until day 60) were investigated through a combined approach based on viable counting and Illumina DNA sequencing. In both the control and experimental cheeses, despite the slight differences emerged depending on the coagulant used, Lactococcus lactis and Debaryomyces hansenii were the prevalent species among bacteria and fungi, respectively. Moreover, raw ewe’s milk was the main factor affecting the evolution of both the bacterial and fungal microbiota in all cheeses. The overall similarities between control and experimental cheeses herein analyzed supports the exploitation of Onopordum tauricum Willd. as an alternative milk coagulating agent for production of Caciofiore and, more in general, raw ewe’s milk cheeses. Full article

In Mediterranean cropping systems, it is important to utilize marginal lands for the cultivation of non-food crops. Spontaneous thistle genera such as Cynara cardunculus L. and Onopordum tauricum Willd. are native to southern Europe. Previous research has focused on their spontaneous growth in the environment or ability to supply biofuel. The aim of this study was to identify the effect of two different planting densities on the flower differentiation, vegetable rennet production and weed control of O. tauricum Willd. and C. cardunculus L. in rainfed unfertilized Mediterranean cropping systems. The results showed that plant density influenced most of the biomass parameters for O. tauricum Willd. but no significant differences were observed for C. cardunculus L. Higher densities of both species were beneficial for weed control. We recommend the use of C. cardunculus L. and O. tauricum Willd. as suitable species for vegetable rennet production in Mediterranean organic cropping systems. Full article

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. Full article