15A-10 |
Fortification of yogurt with calcium salts: Effect on the physico-chemical properties |
J. F. VÉLEZ-RUIZ, Chemical and Food Engineering Department, Universidad de las Américas-Puebla, Sta. Catarina Mártir, Cholula, Puebla., 72820, Mexico Interest in fortification of foods with calcium salts has recently received a great attention, because of the role of this mineral in human nutrition and prevention of diseases. Additionally, it is generally acknowledged that the best dietary sources of calcium are milk and milk products, thus a yogurt fortified with calcium salt may be considered a nutritive and functional product. Therefore, the aim of this study was to manufacture plain whole yogurt and fortified yogurt at different levels, and analyze the influence of the added calcium salt on their physicochemical properties. The fortified and control yogurts were prepared from whole milk powder by following the next steps: rehydration of the milk powder, pasteurization, cooling, fortification, inoculation, incubation, and a final treatment depending of the desired product, stirred (STY) and settled yogurts (SEY). Three levels (100, 200, and 300 mg of salt/100 mL of milk) of calcium lactate and calcium chloride were added to the fortified yogurt. All samples were characterized at the beginning and during the three weeks of storage. pH exhibited a decreasing trend (4.6 to 4.2), and ANOVA results indicated a significant influence of type of yogurt, type of calcium salt, and level of salt; as expected the density of all samples was practically constant; from textural viewpoint, yogurt samples with 100 mg of added salt were considered as the better, recording values of 0.2-0.22 for SEY and 0.1-0.13 kg for STY. All samples showed a shear-thinning behavior, being 4-6 times higher the apparent viscosity of SEY (330-6600 cP) with respect to STY (66-1320) at shear rates lower than 25 s-1. Other analysis, such as acidity, color, syneresis and sensory evaluation were carried out, in order to complete the physicochemical characterization. The acceptability of yogurt fortified with lactate was better than with chloride.
Session 15A, Dairy Foods
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