Escuela de Nutrición y Dietética

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Browsing Escuela de Nutrición y Dietética by Author "Contardo, Ingrid"

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    Conventional and ultrasound-assisted extractions of protein from sacha inchi (Plukenetia volubilis) and their impact on the physicochemical and structural characteristics
    (Applied Food Research, 2024-12) Contardo, Ingrid
    This study aimed to evaluate the recovery of proteins from sacha inchi (SI) cake, using two methods: conventional extraction by alkaline solubilization (SIC, pH 10.5, time 60 min, solvent/sample ratio 40/1) and ultrasound-assisted method (SIUS), the latter undergoing optimization using response surface methodology. The protein powder concentrate obtained by SIUS reached a protein content of ∼ 72 % (dry weight, DW), under the optimized conditions of amplitude: 48 %, solvent/sample ratio: 50 mL/g and time: 19 min at pH 10.5, compared to that obtained using the conventional method with ∼77 % (DW). The physicochemical and structural characteristics differentiate both protein concentrates, the SIUS protein presented a slightly darker color, a narrower size particle distribution, a higher specific surface area, and a manifest denaturation as evidenced by the thermal analysis, compared to that obtained for SIC protein. The structural modifications of the proteins were evaluated by FTIR and circular dichroism (CD) spectroscopy, FTIR showed that the total proteins in SIUS had a decrease in β-sheet and an increase in β-turn configuration, whereas the soluble proteins evaluated by CD presented a marked decrease in α-helix and an increase in random coil and β-sheet configurations. The results contribute to offering information for future applications for both protein concentrates from SI cake in the food sector.
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    Enhancing the Oxidative Stability of Beeswax–Canola Oleogels: Effects of Ascorbic Acid and Alpha-Tocopherol on Their Physical and Chemical Properties
    (MDPI, 2025-01-07) Contardo, Ingrid
    The choice of antioxidant to be used in the formulation of an oleogel is crucial to determine its oxidative stability and functionality, as these factors can also affect the physical, chemical, and rheological properties of the oleogel. In this study, the effect of two antioxidants (ascorbic acid, AA, and alpha-tocopherol, AT) and their concentration (0.01, 0.02, and 0.03%) on the physical and chemical properties of beeswax and canola oil oleogels were evaluated. The results show that the type and concentration of antioxidants did not affect the thermal properties of the samples, and in FTIR analyses, no noticeable changes in spectra patterns are observed. Rheological analyses showed that the oleogels containing AA exhibited higher elasticity and resistance to deformation. Accelerated oxidative stability tests (storage at 50 ◦C and the Rancimat test) showed that AA effectively delayed oxidation. The induction time increased by 2.61-fold at higher concentrations, while AT did not significantly affect oxidation resistance. Overall, it was observed that AA improved oleogel firmness and OBC (up to 1.75-fold and 2.8%, respectively), whereas AT resulted in a softer and less stable gel structure. These results show the importance of antioxidant selection, indicating that hydrophilic antioxidants have promising applications in the formulation of beeswax oleogels.