Starch noodles

Starch noodles, also called glass or cellophane noodles, are thin clear strands made from purified starch rather than from flour. The starch comes from green (mung) beans, peas or sweet potato. Sweet potato starch noodles contain no gluten, which sets them apart from wheat noodles.

The best-known European example is Longkou Fen Si, a name protected in the EU as a PGI by Regulation No 978/2010. It is made in the north of the Shandong Peninsula, in five cities of the Yantai area: Longkou, Zhaoyuan, Penglai, Laiyang and Laizhou. The raw material is green beans or peas, and in the area itself the noodles must go through soaking, settling of the starch paste, beating, filtering and drying in the sun or with hot air. Local spring water with a pH of 6.9–7.4 helps the acid fermentation of the steeping liquid.

The name is traced to 1860, when the Hongtai shop bought vermicelli from Zhaoyuan that was shipped out of the port of Longkou. The specification sets clear limits: more than 75% starch, under 15% moisture, under 0.5% ash, strands thinner than 0.7 mm and fewer than 10% broken after 45 minutes of boiling.

Starch noodles have a weak spot: they are low in protein. That is why researchers try fortifying sweet potato noodles with whey protein, and for mung bean starch they found a −10 °C incubation that raised resistant starch to 15.85%, then applied it to glass noodles.

Why it matters to you. Several different starches hide behind the name "glass noodles", so read the ingredients. For Longkou Fen Si the specification itself fixes the composition: more than 75% starch and less than 15% moisture.