Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora (UNISON), Sonora, 83000, Hermosillo, México.
Grupo Calidad y Seguridad Alimentaria, Departamento de Tecnología de Alimentos, Universidad Miguel Hernández (UMH), Alicante, 03312, Orihuela, España.
Plant Foods Hum Nutr. 2021 Sep;76(3):334-339. doi: 10.1007/s11130-021-00910-x. Epub 2021 Jul 22.
The blue corn-based products are considered functional foods due to their high concentration of anthocyanins. The aim of this study was to estimate the kinetic and thermodynamic parameters of the thermal degradation of anthocyanins from extruded nixtamalized corn products. A comparative study of anthocyanins thermal stability in these matrices in a buffer solution (pH 2.5) was investigated at different temperatures (60, 75 or 90 °C). Results showed the mechanism of anthocyanins degradation followed first-order reaction kinetics. The values of the reaction rate constant (k) were found to be in a range of 0.027-0.037 h at 60 °C, 0.107-0.113 h at 75 °C and 0.340-0.354 h at 90 °C. The higher the k value was, the shorter the half-life time and D-value. The activation energy (Ea) and z-values were in the range of 75.1-89.2 kJ/mol and 28.8-35.1 °C, respectively. The coefficient Q indicated the reaction rate approximately doubles with every 10 °C temperature increase. ∆H, ∆S and ∆G indicated the degradation of anthocyanins was an endothermic and nonspontaneous reaction. Even the major susceptibility of the anthocyanins in extruded nixtamalized corn products at the time-temperature combination applied, there was not difference between flour and tortilla, this imply that most of the anthocyanins were degraded during the nixtamalization extrusion process and no significative further degradation occur in the cooking step. This study provides and advance in the knowledge on the effect of nixtamalization extrusion process and tortillas making on the stability of anthocyanins from blue corn. However, further studies are needed.
基于蓝玉米的产品因其高浓度的花青素而被认为是功能性食品。本研究旨在评估膨化玉米制品中原花青素的热降解动力学和热力学参数。在不同温度（60、75 或 90°C）下，在缓冲溶液（pH 2.5）中对这些基质中花青素热稳定性进行了比较研究。结果表明，花青素降解的机制遵循一级反应动力学。在 60°C 时，反应速率常数（k）的值在 0.027-0.037 h 之间，在 75°C 时在 0.107-0.113 h 之间，在 90°C 时在 0.340-0.354 h 之间。k 值越高，半衰期和 D 值越短。活化能（Ea）和 z 值分别在 75.1-89.2 kJ/mol 和 28.8-35.1°C 的范围内。Q 系数表明，反应速率大约每 10°C 升高一倍。∆H、∆S 和 ∆G 表明，花青素的降解是一个吸热和非自发的反应。即使在应用的时间-温度组合下，膨化玉米制品中原花青素的主要敏感性，面粉和玉米饼之间也没有差异，这意味着在玉米糊化挤压过程中大部分花青素已经降解，在烹饪过程中没有进一步显著降解。本研究为了解玉米糊化挤压过程和玉米饼制作对蓝玉米中原花青素稳定性的影响提供了进展。然而，还需要进一步的研究。
