Cereals processing technology

7.7 Future of the industry
Asian noodle processing 151
7.7.1 New emerging products
Non-fried instant noodles (dry steamed)
As consumers become more health conscious there is an increasing demand for
alternatives to using the saturated 16:0 palm oil, for the production of instant
noodles. An alternative to this is the dry steamed noodle which, after the normal
steaming to gelatinize the starch, are dried using hot air. The primary current
drawback is the slightly longer cooking time, approximately 5 min, and poorer
noodle brightness. At present the use of vacuum mixing to improve starch
gelatinization during the steaming stage, high-temperature (multi-stage) drying
to increase pore size, and the use of low ash, small particle size flours are all
being examined to reduce cooking time. 23 Increasing the initial water absorption
by 2 percent with a special low ash (0.39 percent) flour reduces cooking time by
20 percent and also addresses the issue of color. There are two types of non-fried
instant noodles; non-expanded and expanded with the difference being based on
the internal noodle structure.
To achieve the quick steeping time, non-expanded noodles are generally
thinner or have a large percentage of pregelatinized starch (20 percent)
incorporated into the flour mixture. The non-expanded noodles rely heavily on
vacuum mixing with the associated higher water absorption to improve their
quality by developing the gluten matrix and hydrating the starch. This ensures
the desired chewy texture. The non-expanded noodles are primarily alkaline and
are normally dried at a lower temperature, 60–80ºC, to avoid undesirable
discoloration through phenolic oxidation. The general flour requirement is for a
moderate protein content, above 11 percent, minimum starch damage, small
particle size (less than 70 ) and excellent color through low ash content (less
than 0.40 percent).
Steaming is usually maintained at 98ºC for 2–3 min in the 1 kg/cm 2 pressure
range. It is not uncommon for manufacturers to spray water or emulsifiers onto
the noodles before steaming to aid gelatinization and improve subsequent
rehydration rates. Removal of some of the surface moisture after steaming but
prior to drying has been shown to improve the noodle firmness. The drying
phase is an essential feature for these noodles and is primarily hot air drying
with or without humidity control. Air temperature, speed and humidity will
affect the final quality of the noodle. The benefits of additional humidity control
(25–40 percent) are to ensure an even moisture distribution throughout the
noodle, improve appearance and reduce subsequent cooking loss. 23
The expanded noodles, as the name suggests, have a thicker more porous
structure compared to the non-expanded noodles. The expanded noodles use a
rapid high temperature conversion of water to steam, without frying, to produce
the same porous structure seen in regular instant noodles. The increased porosity
of the expanded noodle within a continuous supporting gluten matrix is the key
difference from non-expanded noodles. No differences due to the manufacturing
process or equipment are required. 23 The difficulty lies in developing the gluten