In vitro assessment of oat ß-glucans nutritional properties: An inter-laboratory methodology evaluation.

The purpose of this inter-laboratory study was to test the repeatability and reproducibility of an in vitro method aimed at analyzing the physicochemical properties under physiological conditions of ß-glucans from foods. After evaluating ß-glucans molar mass and quantification methods using five ß-glucan controls, four laboratories ran six oat-based products through in vitro digestion, measured ß-glucans solubility and viscosity and molar mass of solubilized ß-glucans. The determination of the molar mass of ß-glucan controls, their viscosity in solution and ß-glucans content in food samples exhibited relative standard reproducibility of 20.9-40.9%, 10.2-40.9% and 2.3-14.8%, respectively. After in vitro digestion, relative standard reproducibility ranged 12.1-60.0%, 12.2-64.3% and 9.7-36.3% for molar mass of extracted ß-glucans, their viscosity and their solubility, respectively. Although the characterization methods were satisfactory within the limits of current technology, the in vitro extraction contributed significantly to the uncertainty of final characterization.

Issues surrounding health claims for barley.

Government-approved health claims support dietary intervention as a safe and practical approach to improving consumer health and provide industry with regulatory guidelines for food product labels. Claims already allowed in the United States, United Kingdom, Sweden, and The Netherlands for reducing cholesterol through consumption of oat or barley soluble fiber provide a basis for review, but each country may have different criteria for assessing clinical evidence for a physiological effect. For example, the FDA-approved barley health claim was based on a petition that included 39 animal model studies and 11 human clinical trials. Since then, more studies have been published, but with few exceptions, clinical data continue to demonstrate that the consumption of barley products is effective for lowering total and LDL cholesterol. More research is needed to fully understand the mechanism of cholesterol reduction and the role of beta-glucan molecular weight, viscosity, and solubility. In an assessment of the physiological efficacy of a dietary intervention, consideration should also be given to the potential impact of physical and thermal food-processing treatments and genotypic variation in the barley source. New barley cultivars have been generated specifically for food use, possessing increased beta-glucan, desirable starch composition profiles, and improved milling/processing traits. These advances in barley production, coupled with the establishment of a government-regulated health claim for barley beta-glucan, will stimulate new processing opportunities for barley foods and provide consumers with reliable, healthy food choices.