Preparation
The polysaccharide is prepared by inoculating a sterile aqueous solution of carbohydrate(s), a source of nitrogen, dipotassium phosphate, and some trace elements. The medium is well-aerated and stirred, and the polymer is produced extracellularly into the medium. The final concentration of xanthan produced will vary greatly depending on the method of production, strain of bacteria, and random variation. After fermentation that can vary in time from one to four days, the polymer is precipitated from the medium by the addition of isopropyl alcohol, and the precipitate is dried and milled to give a powder that is readily soluble in water or brine.
In the United States, the manufacture of one kilogram of cheese creates nine kg of the byproduct whey, for which the USDA sought to find more uses. Whey is composed mostly of water and lactose, so researchers developed a strain of X. campestris that would grow on lactose rather than glucose. The newly developed lactose-using bacteria produced 30 g/L of xanthan gum for every 40 g/L of whey powder. Whey-derived xanthan gum is commonly used in many commercial products, such as shampoos and salad dressings.
Read more about this topic: Xanthan Gum
Famous quotes containing the word preparation:
“With memory set smarting like a reopened wound, a man’s past is not simply a dead history, an outworn preparation of the present: it is not a repented error shaken loose from the life: it is a still quivering part of himself, bringing shudders and bitter flavours and the tinglings of a merited shame.”
—George Eliot [Mary Ann (or Marian)
“It’s sad but true that if you focus your attention on housework and meal preparation and diapers, raising children does start to look like drudgery pretty quickly. On the other hand, if you see yourself as nothing less than your child’s nurturer, role model, teacher, spiritual guide, and mentor, your days take on a very different cast.”
—Joyce Maynard (20th century)
“Living each day as a preparation for the next is an exciting way to live. Looking forward to something is much more fun than looking back at something—and much more constructive. If we can prepare ourselves so that we never have to think, “Oh, if I had only known, if I had only been ready,” our lives can really be the great adventure we so passionately want them to be.”
—Hortense Odlum (1892–?)