91C-1 |
Calcium impregnation kinetics of apple matrix |
M. González Fesler1, D. M. Salvatori1, A. Weisstaub2, M. L. Portela2, and S. M. ALZAMORA1. (1) Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Av. Segurola 3842, Piso 2 "D", Buenos Aires, 1419, Argentina, (2) Sanidad, Nutrición, Bromatología y Toxicología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires, 1113, Argentina Foods enriched with minerals are increasingly being consumed because of the strong consumer interest in products with specific health benefits. For calcium fortification of fruit, vacuum impregnation (VI) is a suitable technique (in addition to incorporation by diffusion at atmospheric pressure, AI) to introduce dissolved substances directly into the matrix porous structure, modifying their mineral composition. If the fruit tissue is subjected to previous blanching, matrix impregnation capabilities might be enhanced, although profound structural alterations may occur, affecting calcium transport rate and its distribution throughout the tissue. This work was aimed to study the kinetics of calcium incorporation to apple matrix by a combination of VI followed by AI as well as the feasibility of applying previous blanching to increase the final calcium content. Experiments were conducted at room temperature by immersion of cylindrical samples in agitated isotonic glucose aqueous solutions containing 5.24 % w/w calcium gluconate and lactate salts. 50 mm Hg were applied for a time t1 (0.25-1 h) and then atmospheric pressure was restored and maintained for a time t2 (0.25-6 h). For blanching, samples were immersed in saturated vapour (2 min) and cooled in water. At the end of each treatment, impregnated liquid fraction, calcium content and volume changes were analysed. calcium incorporated by raw tissues ranged from 1200 to 3000 ppm. Increasing t2 had a significant effect on matrix impregnation. But a maximum calcium content was reached very quickly under vacuum conditions, the increase in t1 only slightly affecting the final calcium content. Blanching and 0.25 h under vacuum followed by 6 h under atmospheric conditions allowed to reach 3400 ppm calcium (85 % RDA, 200 g consumption). So the combination of a slight thermal treatment followed by vacuum and atmospheric impregnation techniques leads to an apple matrix with a high level of calcium fortification.
Session 91C, Food Engineering: Food process engineering
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