Scientists seek beta-glucan bread solution

Abdellatif Mohamed, a chemist for the USDA's Agricultural Research Service (ARS) has been experimenting with a powder, derived from barley and oat- bran called C-Trim, which can create a plain white bread with 0.75 grams of beta-glucan per serving.

With bakers joining a growing number of food processors facing increased ingredients costs, methods for ensuring greater profitability in the supply chain, particularly by focusing on health benefits, are increasingly being sought after.

Beta-glucan, a non-starch polysaccharide found in oats, could be one possible area of adding value to the humble loaf of bread.

The ingredient has been the subject of increasing attention with reports showing the soluble fibre can decrease low-density lipoprotein (LDL) cholesterol, linked to heart health problems.

Mohamed has been working on beta-glucan use in bread since 2005, following the unveiling of C-Trim at a meeting of the American Chemical Society in Washington DC.

The C-Trim patented powder, devised by ARS chemist George Inglett can, also cut calories in foods by emulating the properties of fats and carbohydrates, the scientists claim.

Mohamed's work has therefore focused on testing various formulations of high beta-glucan content in bread without sacrificing the taste or aesthetic appeal.

His research has been conducted with the cooperation of Oklahoma State University professor Patricia Rayas-Duarte and ARS physical scientist Jingyuan Xu.

Two different dough types were used in the research, both containing red spring wheat gluten and other bread making ingredients, though varying in the levels C-Trim present, with 17 per cent and 17.5 per cent used respectively.

While C-Trim did not appear to significantly affect the taste, texture or volume of the bread formulations, the research found that the final products were darkened slightly.

At these current levels of C-Trim formulation, Mohammed concluded that four slices of the bread, equivalent to about three grams of beta-glucan, would have to be consumed to deliver any of the potential health benefits.

The researchers claim that the level of bread consumption required could be reduced by supplementing a diet with yoghurt and other products containing the polysaccharide.

For additional testing, the researchers hope to use their current data compiled on C-Trim for use in computer modelling studies, in order to ascertain what changes occur in bread containing about nine grams of beta-glucan.

The researchers highlighted the biochemical affects of beta-glucan use on starch and proteins, which are vital components in volume and shelf-life of bread, as a key area for further study.

There remains some doubt over the health benefits of using beta-glucan in baked goods when compared to products like beverages, according to some studies.

Previous testing using beta-glucan incorporated into beverages, such as oat milk, and other fruit juices reported LDL cholesterol-lowering values.

However, when the ingredient was incorporated into bread and cookies, the results were said to be "non-significant".

In research published last year in the American Journal of Clinical Nutrition (Vol. 83, pp.

601-605), soluble fibre beta-glucan was found to lower LDL (bad) cholesterol, though seemed more efficient when put in beverages.

"These results suggest that the efficacy of beta-glucan preparations increases when they are incorporated into liquid products," said lead author Elke Naumann of Maastricht University, the Netherlands.

The study was a placebo-controlled, double-blind parallel trial of a fruit drink fortified with beta-glucan on LDL-C levels of 47 volunteers.

The participants all drank 500 mL of a rice starch-enriched (placebo) fruit drink every day for three weeks, before being randomly assigned to either the placebo or the beta-glucan fortified drink for a further five weeks.

The researchers reported that, after five weeks, both control and test groups had similar dietary intakes except for beta-glucan intake.

"In the current study, serum concentrations of total cholesterol decreased significantly by 0.060 millimoles per litre (mmol/L) and those of LDL cholesterol by 0.062 mmol/L," reported Naumann.

No significant change in HDL cholesterol, triacylglycerols and total lipid-soluble antioxidants was measured.

However, serum concentrations of lycopene, and alpha- and beta-carotene were found to be lower in the beta-glucan group.

The mechanism behind the LDL-C lowering activity of beta-glucan is not clear, but the researchers proposed that beta-glucan bound to bile acids, thereby preventing reabsorption in the intestine and increasing excretion.

The liver compensates by increasing hepatic cholesterol synthesis to produce more bile.

"We conclude that not only increased bile acid synthesis, but also decreased cholesterol absorption contributes to the cholesterol-lowering effect of beta-glucan," wrote Naumann.

Finding ways to better incorporate potential heart health benefits into baked goods could be a significant, but vital, challenge for the industry in coming years.

According to a report from Leatherhead Food International, the heart health market was valued at $3.6bn (€3bn) market in 2004, and expects that sales will grow by nearly 60 per cent over the period 2004 to 2009, to reach nearly $5.7bn (€4.7bn) by 2009.

Cereals make up the largest slice of the market because they are naturally high in fibre, but foods designed to lower cholesterol reduction continue to dominate in terms of new launches.