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New rice starch extraction method for product savings

02-Feb-2005

Food technologist marks breakthrough in rice starch procurement, replacing a 60-year-old method with a more 'efficient and environmentally-friendly way' to separate a rice kernel's tightly-bound portions of starch and protein, writes Lindsey Partos.

Rice starch, a soft, white powder over twice as expensive as wheat and corn starch, is used by the food industry for its gel strength, gelling temperature and starch granule rigidity.

 

Key applications for the ingredient with a tiny granule size, neutral taste, and soft mouthfeel include baby food, extruded products, soups, dressings and meat preparations.

 

But one of the fastest growing markets for rice starch are functional foods, forecast to double within five years in the UK alone from €1.2 billion to €2.47 billion.

 

Food scientist Harmeet Guraya, based at a US government laboratory, has designed a method to extract rice starch, rivalling the existing sodium hydroxide method, and claiming to cut costs.

 

For over 60 years, processors have accessed rice starch by breaking down milled rice using a corrosive alkali, sodium hydroxide, to slowly dissolve rice protein and release the starch.

 

The new technology developed by Guraya, who works at the Agricultural Research Service in New Orleans, relies on very high pressure, supplied by a homogeniser, known as a microfluidiser, to physically split apart the starch-protein agglomerates.

 

"A single pass through this piece of equipment yields many small, individual particles of starch and protein homogeneously dispersed in a watery matrix. The starch and protein components can then be separated by traditional density-based separation processes," says the researcher.

 

With rice starches significantly more expensive, ranging from about €0.9 to €1.5 a kilo, than their corn and wheat alternatives, the new process could vrey well lift rice starch competitivity in the marketplace.

 

Long-, medium-, and short-grain rices contain varying ratios of the two starch components, amylose and amylopectin.

 

Amylopectin is found in highest concentrations in short-grain (also called 'sticky' or 'waxy') rice. Amylose is highest in long-grain rice-enabling these grains to be separate and fluffy when cooked.

 

Each possess its own unique chemistry, these rice starches have different applications in industry. "With cosmetics and tableting, the kind of starch used is not necessarily important,"explains Guraya, "but with foods, starch type does matter."

 

Starch from waxy rice, for example, exhibits high freeze-thaw stability. "Because this starch holds water well, a food product- like Buffalo wings-will not lose valuable moisture or juices when it is frozen and then thawed," says Guraya.

 

The food technologist is currently working with US rice-based foods firm Sage V Foods, to scale up the new technology to a complete production line. Food products are still at the development stage.

 

Guraya believes his approach could help rebuild the rice starch and protein production industries in the US, which now imports about $40 million worth of rice starch each year.

 

But others are likely to also benefit, namely number one European rice starch provider Remy Industries. Improved extraction methods should ultimately bring cost-savings for firms competing in the global 48.5 million ton starch arena.

 

A spokesperson at Remy told FoodNavigator.com that, in addition to baby food and health products, a key growing area for their rice starch portfolio is in the area of organics.

 

Native rice starch is well adapted to organic final products, falling beneath the five per cent non-organic tolerance rule, said a spokesperson.

 

For the most part, the company buys in the rice raw material from Asia, South America, Italy and Spain.

 

But competing in the mainstream commodity starch arena is extremely difficult, particularly when it is not the commodities themselves that are the competition, but rather the functional characteristics of the value-added products.

 

When aiming at functional properties in starch, most commercial companies examine the characteristics of competitive starches in particular applications. This sets the target to shoot for, said Morton Satin in a recent report for the UN-backed Food and Agriculture Organisation (FAO).

 

Market analysts SK Patil and Associates estimate that total use of starch will hit 70 million tons by 2010 on annual (global) growth of 2.2 per cent. Growth in the US at 0.65 per cent, the EU at 0.2 per cent and Japan at 0.18 per cent will be very slight, while for the rest of the world the market rise is pitched at 2.25 per cent.

 

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