Microstructural changes and micronutrient bioaccessibility in soft-solid foods, using a model fresh cheese and in vitro digestion

Castaneda Lazo, Blanca Nuria

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Description

Title

Microstructural changes and micronutrient bioaccessibility in soft-solid foods, using a model fresh cheese and in vitro digestion

Author(s)

Castaneda Lazo, Blanca Nuria

Issue Date

2016-12-07

Director of Research (if dissertation) or Advisor (if thesis)

Lee, Youngsoo

Department of Study

Food Science & Human Nutrition

Discipline

Food Science & Human Nutrition

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Food Microstructure
• Bioaccessibility
• Vitamin D

Abstract

Processed food products are complex matrices with many components interacting below 100 μm. These interactions will dictate the characteristics of product from a physical, chemical and nutritional point of view. The increasing demand for food products with health benefits and functional properties encourages the use of material and physical science to understand how food components interact at the mesoscale. The fundamental understanding of this interaction and its relationship will open new windows for food engineering and innovation to create structures with specific functionalities especially for nutritional availability in processed food matrices. The overall objective of this study was to evaluate the structural characteristics of a soft solid matrix created by variations in formulation and processing parameters, and its relationship with the bioaccessibility of liposoluble vitamins through in vitro digestion. There were two specific aims to accomplish the overall objective. The first aim was to evaluate the structure and microstructure of the soft solid matrix, using a model fresh cheese processed at a various protein to fat ratios and homogenization pressures by means of textural, rheological and image analysis. The second aim was to evaluate the bioaccessibility of liposoluble vitamins through in vitro digestion by fortifying a soft solid matrix with vitamin D3, using a model fresh cheese processed at a various protein to fat ratios and homogenization pressures. To accomplish these objectives, a model fresh cheese was prepared at various protein to fat ratios and homogenization pressures. Particle size of the cheese milk emulsion was analyzed by laser diffraction. Structural parameters were measured by large and small deformations using Texture Profile Analysis (TPA) and Small Amplitude Oscillatory Shear (SAOS) rheology. Microstructure, specifically pore size, and porosity was analyzed by Environmental Scanning Electron Microscopy (ESEM) micrographs. Three experimental units (containing the lowest and highest protein to fat ratios and lowest and highest homogenization pressures) were selected for vitamin D3 bioaccessibility analysis using an in vitro digestion model. Protein to fat ratio and homogenization pressure significantly affected the particle size of the cheese milk emulsion. At higher protein to fat ratio and homogenization pressure particle size was reduced significantly. Similarly, at a higher protein to fat ratios and homogenization pressures samples were significantly harder and cohesive at large deformations, however, no clear trend was seen from small deformations nor porosity. On the other hand, bioaccessibility of vitamin D3 decreased at higher protein to fat ratios and homogenization pressures suggesting higher protein-protein interactions during the processing of the model cheese and perhaps lower protein hydrolysis during the in vitro digestion. The study of complex food matrices needs further investigation since many factors regarding constituents as well as processing, are interacting together. Critical interactions between food components during processing are directly related to the physical characteristics of food products as well as their behavior during digestion. Therefore, understanding the food matrix and its behavior during processing and digestion is essential for engineering food structure with specific functionality.

Graduation Semester

2016-12

Type of Resource

text

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Copyright and License Information

Copyright 2016 Blanca Castaneda Lazo

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