are so much smaller and lighter than intact starch granules and cell fragments, they don’t settle out and separate And they are too small and too widely separated to block the passage of light rays: so unlike suspensions, molecular dispersions are usually translucent and glassylooking In general, the longer the molecule, the better it is at obstructing water movement, because long molecules more readily get tangled up in each other So a small quantity of long amylose starch molecules will do the same thickening job as a large quantity of short amylopectin (p 611), and long gelatin molecules thicken more efficiently than short ones Thickening with molecules often requires heat, either to liberate the molecules from the larger structures — starch molecules from their granules, gelatin molecules from meat connective tissue — or to shake out compactly folded molecules — egg proteins — into their long, extended, tangly form Solid Dispersions: Jellies When the water phase of a food fluid has enough thickening molecules dissolved in it, and the fluid is left undisturbed and allowed to cool, those molecules can bond to each other and form a loose but continuous tangle or network that permeates the fluid, with the water immobilized in pockets between the network molecules Such a network thickens the fluid to the point that it becomes a very moist solid, or a gel It’s possible to make a solid — if wobbly — jelly that is 99% water and just 1% gelatin If the gel is made from dissolved molecules, then it will be translucent, like the dispersion from which it is formed Familiar examples are savory jellies made from gelatin and sweet jellies made from fruit pectin If the solution also contains particles — the remains of starch granules, for example — then the jelly will be opaque ... Dispersions: Jellies When the water phase of a food fluid has enough thickening molecules dissolved in it, and the fluid is left undisturbed and allowed to cool, those molecules can bond to each other and form a... examples are savory jellies made from gelatin and sweet jellies made from fruit pectin If the solution also contains particles — the remains of starch granules, for example — then the jelly will be opaque ... molecules can bond to each other and form a loose but continuous tangle or network that permeates the fluid, with the water immobilized in pockets between the network molecules Such a network thickens the fluid to the point that it becomes a very moist solid,