The relationship between ultrasound measurements and empty body and carcass chemical composition was investigated. A 500-V real-time ultrasound with a 7.5-MHz probe combined with image analysis was used to make in vivo measurements to predict the empty body and carcass chemical composition of 31 female lambs of two genotypes, ranging in BW from 18.2 to 48.9 kg. Eleven ultrasound measurements of s.c. fat, muscle, and tissue depth were taken at four different sites (over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, at the 3rd sternebra of the sternum, and over the 11th rib, 16 cm from the dorsal midline). The single best predictor of empty body fat quantity and energy value was the s.c. fat depth over the 13th thoracic vertebra (r² = 0.904 and 0.912; P <0.01, respectively). Body weight was used with ultrasound measurements in multiple regression equations to establish the best independent variables combination for predicting chemical composition. Results showed that BW and two of the three ultrasound measurements (s.c. fat depth over the 13th thoracic vertebra, between the 3rd and 4th lumbar vertebrae, and tissue depth over the 11th rib, 16 cm from the dorsal midline), explained 94.7 to 98.7% (P < 0.01) of the quantity of water and fat and the energy value variation in the empty body and carcass. Body weight per se was the best predictor of the quantity of protein, accounting for 97.5 and 96.8% (P < 0.01) of the variation observed in the empty body and carcass, respectively. The results of this study suggest that BW and some ultrasound measurements combined with image analysis, particularly subcutaneous fat depth over the 13th thoracic vertebra, allow accurate prediction of empty body and carcass chemical composition in lambs.

The olive oil industry generates large volumes of by-products, creating notable environmental and economic concerns. Among these, olive cake (OC)—a primary by-product of olive oil extraction—stands out due to its high content of bioactive compounds and potential for value-added recycling. This study focused on characterizing six OC samples from the Trás-os-Montes and Alto Douro regions, collected at different processing times and mills. The samples included two derived from pressing (COC), two from two-phase centrifugation (TPOC; one partially pitted and one dehydrated), and two exhausted OC (EOC) samples. Fundamental analyses assessed total phenols, ortho-diphenols, flavonoids, antioxidant capacity, and tannin content. Results revealed significant variation (p < 0.05) in phenolic composition, namely ortho-diphenols and flavonoid levels among the samples. EOC 2 exhibited the highest concentrations (19.61, 21.82, and 20.12 mg CAT/g, respectively), while COC 2 had the lowest (5.08, 5.08, and 2.76 mg GA/g, respectively). This correlated with elevated antioxidant activity in EOC 2, as measured by FRAP, DPPH, and ABTS assays (129.98, 78.00, and 56.65 μmol Trolox/g). In contrast, COC 1 and COC 2 displayed the lowest antioxidant activities (32.61 μmol Trolox/g in FRAP and 17.24 and 18.98 μmol Trolox/g in DPPH). Tannin analysis showed the highest total tannin content in the dehydrated and pitted OC samples (250.31 and 240.89 mg CAT/100 g), with COC 2 showing the lowest (88.17 mg CAT/100 g). Condensed tannin content varied significantly, with EOC 2 presenting the highest level (328.17 mg CAT/100 g) and COC 2 the lowest one (20.56 mg CAT/100 g). Through HPLC-PDA-MS, 22 compounds were identified, with luteolin and verbascoside being particularly prevalent. This in-depth characterization supports the potential valorization of olive by-products, advancing sustainability and promoting a circular economy in the olive oil sector.

The olive oil industry, recognised for its beneficial products for health and food culture, generates a significant amount of by-products that, if not appropriately managed, can pose considerable environmental challenges. This study examined six olive cakes (OC) from the Trás-os-Montes and Alto Douro regions, collected on different dates and mills: two obtained by pressing (COC), two by centrifugation (TPOC), including one partially pitted and one dehydrated, and two exhausted (EOC), which were subjected to conventional chemical analyses, namely dry matter (DM), organic matter (OM), crude fat (CF), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) profiling fatty acid (FA) and phosphorus and phytic acid content. The dehydrated TPOC had only 8% moisture content (due to drying), followed by EOC with 10% and COC (65–79%). The CF content was high in COC 1 (14.5% in DM), residual in EOC (1.5%) and intermediate in TPOC (9–10%). CP ranged from 5.3 to 7.3%. Notably, NDF levels were high (>65% in 5 samples; pitted TPOC 57.4%) and very lignified (ADL > 23%). Different FA profiles were observed: COC had the highest monounsaturated (76.36 g/100 g), while EOC had the highest saturated (16.56 g/100 g) and polyunsaturated (14.14 g/100 g). Phosphorus and phytic acid content (g/100 g) of EOC 2, TPOC pitted, TPOC dehydrated, COC 1 and COC 2 showed similar values to each other (mean of 0.12 ± 0.02 and 0.44 ± 0.0, respectively), with EOC 1 having the lowest levels (0.07 ± 0.01 and 0.26 ± 0.04, respectively). These results highlight the potential of OCs, especially dry TPOC, which offers transport, conservation and utilisation benefits.