blanching promoted the elution of free sugars of low molecular
weight. Free sugars such as sucrose and fructose absorb relatively
less water than high molecular weight dietary fibres. Therefore,
more high molecular weight dietary fibre existed per unit weight
of dry matter in blanched samples, and consequently blanched
samples were able to hold more water per unit weight. This property
is useful in the preparation of processed foods. However, unlike
potato starch, Jerusalem artichoke tuber samples did not
gelatinise during heating.
Next, the oil-holding capacity was examined, because it is also a
preferred property in the food processing industry. The results are
shown in Fig. 1B. Potato starch, as a control, absorbed only 1 ml of
cottonseed oil at either 40 or 80 C. Jerusalem artichoke tuber samples
absorbed almost the same volume as potato starch did. Unblanched
samples and samples blanched for 120 s absorbed
slightly more oil at higher temperature; however, the amount absorbed
would not be enough to satisfy industrial requirements.