Browsing by Author "Fito, Pedro Juan"

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Dielectric spectroscopy for the prediction of pork quality during the post-mortem time
(Elsevier, 2025-08) Chuquizuta Trigoso, Tony Steven; Peralta, Magaly; Medina, Sideli; Arteaga, Hubert; Oblitas, Jimy; Chavez, Segundo G.; Castro, Wilson Manuel; Castro-Giraldez, Marta; Fito, Pedro Juan
Dielectric spectroscopy was used in this study to predict and classify pork quality during the post-mortem time. Eighty ~1 kg- longissimus dorsi muscles were collected and stored at 4 ± 1 ◦C and pH, instrumental color, and dielectric properties (ε’ and ε’’) were subsequently determined in the microwave range (0.5–9 GHz) at 3, 4, 5, 6, 7, 8, 9, 10 and 24 h post-mortem (hpm), as well as moisture at 8 hpm and drip weight loss at 24 hpm. Of the 80 pork samples, two types of meat were found. RFN (33) and DFD (47) between males and females. Quality parameters: RFN (pH=5.708–5.714; L*=43.341–43.692; moisture (%) = 68.857–69.604; drip loss = 1.655–1.833) and DFD (pH=6.154–6.177; L*=40.152–41.91; moisture (%) = 69.032–69.9; drip loss = 1.129–1.693). Quality parameter predictions during muscle-to-meat transformation showed R² of 0.743 (pH), 0.811 (L*) and 0.603 (C*) for DFD meats with PLSR (full) and R2 of 0.359 (pH), 0.558 (L*) and 0.284 (C*) for RNF meats with PLSR (optimized) from male pigs. R2 cv of 0.412–0.637 for pH, L* and c* for RFN and DFD meats from female pigs with PLSR (optimized). Dielectric spectroscopy predicts pork quality moderately well, but models that are more robust are needed to improve predictions of internal pork quality.
Non-invasive monitoring of goldenberry freezing using infrared thermography and radiofrequency dielectric spectroscopy.
(Elsevier, 2025-07) Chuquizuta Trigoso, Tony Steven; Castro, Wilson Manuel; Castro-Giraldez, Marta; Fito, Pedro Juan
This study presents a non-invasive monitoring system combining infrared thermography and radiofrequency dielectric spectroscopy to characterize the freezing behavior of goldenberry (Physalis peruviana). The system enabled simultaneous acquisition of surface temperature profiles, internal dielectric responses, and emissivity changes during freezing at − 40 ◦C. Thermal imaging revealed distinct freezing stages, including subcooling, ice nucleation, and vitrification, with emissivity decreasing to 0.837 during initial dehydration and increasing to 0.951 near the glass transition (− 35.8 ◦C). Emissivity variations revealed key thermal transitions, while dielectric measurements identified α- and β-dispersions linked to ionic straight and surface tension of ice Ih formation, with relaxation frequencies decreasing progressively as freezing advanced. The integration of both techniques allowed the detection of critical phase transitions, including the onset and completion of ice crystallization, supported by differential scanning calorimetry. These findings provide insight into structural changes and water mobility in high-moisture fruits, enabling real-time assessment of freezing kinetics. The approach demonstrates significant potential for optimizing industrial freezing protocols, improving the preservation of delicate fruits by minimizing structural damage and degradation of bioactive compounds.