Alginate may lead to low GI rice noodles: Nestle

“Results are promising for the development of commercial rice noodles with superior appearance, textural profile and digestibility,”​ wrote the researchers from the National University of Singapore and Nestle R&D Center, Singapore, in the journal Food Hydrocolloids​.

“Product development work is on-going but for the moment the ability of the alginate containing rice noodle to deliver an acceptable organoleptic property following steaming, frying and boiling is extremely encouraging,”​ they added.

The instant noodle market is growing. According to a US Department of Agriculture emerging market project proposal, manufacturers of instant noodles are searching for “a new formula for the next noodle generation that can be higher in protein, better quality, and yet cheaper”.​

Study details​

The researchers set the alginate (ISP) externally with calcium within the dough and found this to reduce the cooking loss and leakage of starch during boiling. Use of scanning electron microscopy (SEM) showed that alginate had a “dramatic effect”​ on the “morphology of rice dough”​.

The researchers then used these laboratory results to scale up the preparation, and test the alginate-rice dough for soup-based rice noodles at the pilot plant scale.

“Unlike wheat dough, the lack of gluten in rice causes rapid water evaporation and the formation of brittle structures that disintegrate readily,”​ explained the researchers.

The pilot plant steps involved “mixing of ingredients, dough sheeting and slitting, spraying of an appropriate calcium chloride solution onto the noodle surface, waiving and cutting of noodle strands, steaming, and frying in the desired commercial size portions”​.

The pilot plant tests showed that formulation with alginate produced “distinctive strands with very acceptable eye appeal”, while formulation without alginate produced lumpy and sticky noodles.

In addition to improvements in the texture of the noodles, the researchers added that the alginate-formulation may also retard the digestion of amylase of the dough in vitro​.

“It remains to be seen if results can be followed through with ​in vivo studies thus reducing the relatively high glycemic index of instant rice noodles,”​ they concluded.

The glycaemic index measures how quickly certain foods release carbohydrates into the body, which then raise consumers' blood glucose levels. High GI foods, including white bread, white rice, many prepared breakfast cereals and concentrated sugar, cause blood sugar levels to rise more rapidly. Low GI foods include most vegetables, fruits, beans and unprocessed grains.

Source: Food Hydrocolloids​ Volume 23, Issue 6, Pages 1458-1464“Structural enhancement leading to retardation of in vitro digestion of rice dough in the presence of alginate”​ Authors: L.W. Koh, S. Kasapis, K.M. Lim, C.W. Foo