Cooking quality of cooked spaghetti extruded from rice flour
mixed with DSF is summarized in Table 7. Cooking time and tensile
strength of the various blends of cooked rice pasta were not
significantly different (p > 0.05). The decrease of cooking weight
from 275 to about 252e260 g/100 g dry pasta with DSF substitution
at 5e15 g/100 g blend may suggest a lower hydration of the pasta
when cooked as described above. The trend toward increased
cooking loss with increased levels of DSF was similar to that of a
pasta product made from sweet potato fortified with soy protein, as
reported by Limroongreungrat and Huang (2007). The addition of
DSF, consisted of soy protein, crude fiber and other ingredients,
could disrupt the starch matrix allows more of the starch leaching
out during the cooking process. Good-quality pasta should have a high degree of firmness. Cooked noodles showed the high hardness
(64.3 N) with rice flour: DSF at 90:10; hardness decreased to 54.5
and 51.4 N when DSF was added to rice flour at 87.5:12.5 and 85:15.
The competition for water by soy proteins with gluten and starch
induced positive effects in pasta made from durum wheat semolina
and toasted soy flour in term of resistance to cooking (Baiano et al.,
2011). In comparison, the hardness of brands A and B was 56.2 and
83.9 N, respectively.