Development of Functional Casu Axedu Cheese Enriched with Olive Leaf Phenolics and a Probiotic-Candidate Lactiplantibacillus plantarum Strain

Functional fresh cheeses can serve as effective carriers of bioactive compounds and probiotic cultures. This study developed a Casu Axedu cheese fortified with olive leaf phenolics and a probiotic-candidate Lactiplantibacillus plantarum (LP) strain. Three formulations were produced from thermised sheep milk: a control (CA-I), a cheese with LP (CA-IL) and a cheese combining olive leaf extract (OLE; 20 mg GAE 100 g−1 milk) and LP (CA-IOL). In all experimental cheeses, inulin was included as a dietary fibre, and lactose hydrolysis was performed to improve product accessibility for lactose-intolerant consumers. Cheeses were stored at 3 ± 1 °C for 30 days and analysed for polyphenol profile, antioxidant capacity, physicochemical and nutritional characteristics, microbiological quality, sensory properties and consumer acceptance. OLE fortification approximately doubled the total polyphenols and produced a more than threefold increase in FRAP antioxidant capacity in CA-IOL, with a high percentage of the main olive leaf phenolics retained after 30 days. Composition, fatty acid profile, vitamin A/E and cholesterol contents were unaffected by OLE and LP addition; all formulations met “high in protein” and lactose-free label criteria (according to the guidelines issued by the Italian Ministry of Health DGISAN Communication No. 27673 of 7 July 2015), and the inulin-based “source of fibre” claim was supported by formulation and mass-balance calculation. Presumptive lactobacilli remained at high counts throughout storage in the LP-containing cheeses, and OLE neither impaired the lactic microflora nor promoted coliform growth. OLE addition increased perceived bitterness, astringency and olive-like notes in CA-IOL, moderately reducing liking scores relative to those of the control among the tested consumer panel (5.25 ± 1.7 at 30 d); mean liking nonetheless remained above the neutral point of the 9-point hedonic scale. Overall, combining inulin, olive leaf extract and a probiotic-candidate L. plantarum strain enabled the production of a Casu Axedu cheese with enhanced antioxidant properties and improved nutritional features while retaining acceptable sensory quality. This approach represents a promising strategy for the valorisation of olive by-products and the development of innovative sheep milk dairy products consistent with circular economy principles.