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theses

High pressure processing (HPP) is a technology in which foods are subjected to high pressures in the range 100 MPa – 800 MPa. HPP has been greatly explored as a process technology for ensuring food safety in the past. Recently, this technology has shown a great promise to enhance the infusion of biomolecules into food systems. The aim of this project was to explore and evaluate HPP as a technique for infusion of calcium in a food matrix, specifically baby carrots. HPP was employed in infusing calcium in PME (pectin methylesterase) treated baby carrots. Calcium lactate gluconate (CLG) salt was used as the infusate solution. The effect of HPP was evaluated on the extent of calcium infusion in baby carrots along with its effect on other important attributes of baby carrots, such as beta-carotene extractability, hardness (N), and color. In addition, the effect of pressure cycling on calcium infusion were also studied. Fifteen HPP experiments were performed following a Box-Behnken design of experiments. The three independent factors evaluated were pressure (MPa), time (min), and CLG solution concentration (% w/v). To evaluate the effect of pressure cycling, high pressure infusion was carried out by varying the number of cycles as 1, 3, and 5 keeping the maximum pressure level, the total hold time at maximum pressure, and the maximum CLG solution concentration fixed. Unprocessed baby carrots, osmotically infused baby carrots, and vacuum infused baby carrots were used as controls. It was observed that HPP enhanced the infusion of calcium in PME treated baby carrots from 19.5 mg/serving to up to 134 mg/serving of baby carrots, which is more than 10 % of the RDA of calcium, and was more than 3 times the amount of calcium infused in osmotically and vacuum infused controls. The processing variables of pressure, time, and CLG concentration, all played a significant role in determining the amount of calcium infused. The amount of infused calcium increased with the number of pressure cycles (1 to 5). The extractability of beta-carotene from the HPP calcium infused baby carrots was 4-5 times higher than the unprocessed control. The hardness of the baby carrots was observed to increase after calcium infusion, but the color of the carrots became darker. Microbial shelf life of the calcium infused baby carrots was observed to be only 4 days, indicating that further research is needed to optimize the handling and post-processing techniques. In conclusion, HPP was found to enhance the infusion of calcium in PME treated baby carrots while also improving the extractability of beta-carotene and increasing the hardness, but darkening the color.

ETD_7166

M.S.

Includes bibliographical references

by Noopur Sanjay Gosavi

doi:10.7282/T37083K5

ETD graduate

The author owns the copyright to this work.