Food additive : E285 Borax 硼砂

Borax ( 硼砂 ) also known as sodium borate, sodium decahydrate, sodium tetraborate or disodium tetraborate.  It is more accurately called  sodium tetraborate decahydrate with chemical formula Na₂B₄O₇·10H₂O or Na₂[B₄O₅(OH)₄]·8H₂O.

Powdered borax is transparent white crystal powder, odorless  and water soluble

Borax occurs naturally in evaporate deposits produced by the repeated evaporation of seasonal lakes.  

History

Borax was first discovered in dry lake in Tibet and was imported via the Silk Road to the Arabian Peninsula in the 8^th century.   Borax came into common use in the late 19^th century when Francis Marion Smith’s Pacific Borax Company began to market and popularize borax usage as a cleaner.

Food Additive

Borax, given the E number E285, is used as a food additive, but is banned in some countries.  In addition to its use as a preservative, borax imparts a firm, rubbery texture to food.   It has been found in foods especially noodles.

Borax is not acutely toxic. Its LD₅₀ score is tested at 2.66 g/kg in rats, meaning that a significant dose  of the borax is needed to cause severe symptoms or death for an average size human adult.  The lethal dose is not necessary correspondence to human.

However, there are studies suggesting possible higher risk of liver cancer with high consumption of borax over a long period of time.