Chemical, microbiological, textural, and sensory characteristics of pilot-scale Caciofiore cheese curdled with commercial Cynara cardunculus rennet and crude extracts from spontaneous and cultivated Onopordum tauricum

The aim of this study was the chemical, microbiological, textural, and sensory characterization of pilot-scaleprototypes of an Italian ewe’s raw milk cheese (Caciofiore) curdled with commercial Cynara cardunculusrennet, used as a control, and crude extracts obtained from flowers of either spontaneous or cultivated Onopordumtauricum. Hence, the control and experimental cheese prototypes produced in two rounds of cheesemakingtrials were assayed, at the end of their 60-day maturation, for the following features: pH, titratableacidity, dry matter, fat, total and soluble nitrogen (TN and SN, respectively), ash, salt, protein, lactose, viableplate counts and composition of the bacterial and fungal populations, color, texture, volatile organic compounds(VOCs), and olfactory attributes by sensory analysis (the latter for the sole prototypes curdled with the commercialrennet and the extract obtained from cultivated O. tauricum). The data overall collected showed a verylow impact of the type of thistle rennet on the analyzed cheese traits, with significant differences being exclusivelyfound for SN/TN%, titratable acidity, color, and adhesiveness. By contrast, a higher impact of thecheesemaking round was seen, with significant differences being observed for salt content, load of presumptivelactobacilli, thermophilic cocci, and Escherichia coli, and levels of the following VOCs: 2,3-butanedione, 2-pentanone,1-butanol, 2-heptanone, 3-methyl-1-butanol, 2-heptanol, 2-nonanone, dimethyl trisulfide, 2-methylpropanoic acid, butanoic acid, and 3-methyl butanoic acid. Sensory analysis revealed a strong ewe’s cheeseodor, accompanied by other olfactory notes, such as pungent, sour curd, sweet, and Parmesan cheese-like notes,in all the analysed cheese prototypes. Moreover, key odor active compounds, including butanoic acid, ethylbutanoate, 2,3-butanedione, 1-octen-3-one, and dimethyl trisulfide, were identified by GC-olfactometry analysis.Regarding the odor attributes as determined by sensory analysis, again the type of rennet had an almostnegligible impact, with significant differences being only perceived for 1 or 2 out of 20 odor attributes,depending on the analytical conditions applied. Although some aspects deserve further investigation, the resultsherein collected confirm that O. tauricum can be regarded as an alternative source of thistle rennet for themanufacture of Caciofiore cheese, and more in general, Mediterranean ewe’s milk cheeses.