temperature approaches the boiling point, the
cell walls begin to weaken. The cellulose
framework remains mostly unchanged, but the
pectin and hemicellulose “cement” softens,
gradually breaks down into shorter chains, and
dissolves. Teeth now easily push adjacent
cells apart from each other, and the texture
becomes tender. Prolonged boiling will
remove nearly all of the cell-wall cement and
cause the tissue to disintegrate, thus
transforming it into a puree.
Acid and Hard Water Maintain Firmness;
Salt and Alkalinity Speed Softening The
wall-dissolving, tenderizing phase of fruit and
vegetable cooking is strongly influenced by
the cooking environment. Hemicelluloses are
not very soluble in acid conditions, and
readily soluble in alkaline conditions. This
means that fruits and vegetables cooked in an
acid liquid — a tomato sauce for example, or
other fruit juices and purees — may remain