'Waxy wheat' produces low calorie bread

The trend for low fat foods continues to grow as weight-conscious consumers increase annually in numbers. US scientists might have the answer for those consumers keen to shed a few kilos without sacrificing that diet staple, bread.

Scientists at the US Agricultural Research Service have bred a new kind of durum wheat, called "waxy wheat," whose flour may give rise to reduced-fat bread.

In commercial baking, vegetable oil or other types of fat are often added to dough to produce loaves of bread with improved crumb softness, volume and texture. Shortening also keeps the bread from becoming stale too quickly during storage.

But vegetable shortening is high in trans fatty acids and can be a costly ingredient to add when millions of loaves are being produced, according to chemist Doug Doehlert at the ARS Red River Valley Agricultural Research Center.

Doehlert and North Dakota State University associates have revealed that flour from the new waxy durum wheat (WDW) can replace vegetable shortening without losing the desired properties the shortening confers to bread. A single bread loaf might have two tablespoons of shortening, so replacing that with WDW flour would save about 26 grams of fat, or 234 calories.

Doehlert credits the flour's fat-replacing capacity to a unique type of starch that differs from that in most bread wheat cultivars.

Starch is a polymer, or chain, of glucose molecules containing both amylose and amylopectin. Amylose is the straight-chain form of this polymer, while amylopectin is the branched form. Most wheat cultivars have about 24 per cent amylose and 76 per cent amylopectin. But WDW starch is nearly 100 per cent amylopectin.

WDW flour works best as a shortening substitute when it comprises 20 per cent of a dough formulation, according to Doehlert, at the centre's Cereal Crops Research Unit. In trials, quarter-pound loaves of the experimental bread had the same softness, texture and volume as those containing 100 per cent bread wheat flour and 3.25 grams of shortening. And in tests for freshness, the WDW bread stayed much softer than the non-waxy wheat bread after five days of storage.

Doehlert, along with ARS chemist Linda Grant and NDSU associates Monisha Bhattacharya, Sofia Erazo-Castrejon and Michael McMullen, have been developing, evaluating and testing applications for the new WDW flour for about five years.

HealthCentral.com​ ARS is the US Department of Agriculture's chief scientific research agency.