E. Flores-Andrade

Effect of borojo (Borojoa patinoi Cuatrecasas) three-phase composition and gum arabic on the glass transition temperature

BACKGROUND The search for natural, novel, high-quality, stable food ingredients is an ongoing practice in the food industry. Pulp of borojo (Borojoa patinoi Cuatrecasas), which is a fruit of the Colombian Pacific region, can be separated into three phases: liquid (LP), medium (MP) and solid (SP) phases. The objective of this work was to evaluate the effect of the three-phase composition and gum arabic on their glass transitions temperatures (T(g)). The best mixture, LP-MP, MP-SP and LP-SP and gum arabic (GA) was identified by response surface methodology. RESULTS When adding GA to SP borojo phase in a 1:1 proportion, the resulting T(g) of the mixture was 132.27 °C whereas Tg for GA and SP-phase were 154.89 °C and 79.86 °C respectively, which supported this combination as attractive from a processing perspective and supports an industrial advantage of using borojo as food ingredient. Phases were characterized by high-performance liquid chromatography, Fourier transform infrared spectroscopy, confocal laser scanning microscopy and mass spectrometry. Low molecular weight compounds such as fructose for MP lowered T(g) whereas the presence of lignin increased T(g) of the mixtures as with the SP. CONCLUSIONS The addition of GA significantly increased T(g) of borojo phases so leading to propose them as novel food processing materials.

Fractal surface analysis and thermodynamic properties of moisture sorption of calcium–sucrose powders

ABSTRACT Fractal analysis, using water adsorption and an image analysis technique, was applied to investigate the effect of surface irregularities on the thermodynamic properties of matrix calcium–sucrose powder moisture sorption. The sorption isotherms were evaluated at 15, 25, and 35°C for calcium–sucrose powders obtained by a cryogenic process (CP) and spray drying (SD). Solubilization of the powders was observed after 20 days of storage at 25°C, and the powder CP had greater physical stability than SD. There was good agreement among the fractal dimension computed by scanning electron microscopy analysis and water adsorption isotherm. The surface fractal dimensions were between 2.19 and 2.44 for CP and were larger than those obtained for SD, which were between 2.11 to 2.26. The differential and integral enthalpies increased as the surface geometry became more irregular, also increased the interactions between the powder surface and water molecules. These results suggested that the increase in the matrix irregularities for a product can displace the minimum integral entropy toward high water activity, thereby improving the storage stability.