Foods have a microstructure imparted either by nature or through processing. The relevance of structure in engineering is that practically all relevant properties are structure sensitive. As discussed by Aguilera and Stanley (1999), the microstructural engineer understands food processing as a controlled effort to preserve, transform, destroy, or create structures (Fig. 1).

Fig. 3—Oil distribution in the crust of a fried potato chip. Three-dimensional reconstruction of confocal laser scanning microscopy images using the Imaris software. Note eggbox arrangement of oil around phantoms of cells. From Pedreschi et al. (1999)Preserving structure is a major objective in postharvest technology of plant material as well as in postmortem handling of…

Fig. 1—Relation between food processing and the structure of foods. Adapted from Aguilera and Stanley (1999)

Fig. 2—Microstructural approach to food product engineering and structure property–relationships derived from it (center). This approach is centered on the product (left). Conventional view of food processing (right)

Table 1 Distinctive aspects of chemical engineering and food product engineering

Table 2 Level of structures, scales, and their relevance in processing of fruit materials

Fig. 4—Compressive stress for mixed cassava starch–whey protein isolate gels of different total solids content as a function of starch concentration. Phase inversion occurs when starch becomes the continuous phase (scheme)

Fig. 5—Growth of a sucrose crystal from the rubbery phase, shown by polarized light videomicroscopy (left). Change in crystallinity with time and Avrami plot of kinetic data (right)

Fig. 6—Characterization of the surface of a chocolate bar. Log-log plot of relative area (apparent area divided by the projected area) vs the area (scale) of the patch used in the tiling exercise. Parameters characterizing the surface are the smooth–rough transition (SRC) and the area-scale fractal complexity (ASFC)

Premium Content
You've reached your monthly limit of free articles.
Access Food Technology
Log in Subscribe