The U.S. FDA allowance of health claims for -glucan soluble fiber from oat will increase the demand for this fiber that is plentiful in waxy hulless barley (WHB). Organizations are in the process of requesting a similar allowance for -glucan soluble fiber from barley. Our research has examined storage characteristics of the grain and milled products from WHB and value-added product development.

Grain Storage

Three waxy hulless cultivars and Robust and Bowman were grown at four locations in North Dakota during 1994 and 1995. Two of the WHB cultivars were developed by backcrossing; thus, 'Rowax' was bred from 'Robust' and 'Bob' was bred from 'Bowman'. Samples were stored at 4 ^oC and 25 ^oC and initial moisture levels of 10% and 13% for one year. Changes in water activity (Aw), free fatty acids (FFA) and thiobarbituric acid-malondialdehyde (TBA-MDA) were measured at three month intervals to monitor lipid oxidation.

Environment had a significant effect on the initial levels of FFA and TBA-MDA. FFA in harvested samples ranged from 2.07 to 8.57 mg/g in 1994, and from 0.89 to 4.07 in 1995. MDA ranged from .311 to .617 ug/g in 1994 and from .390 to 1.058 ug/g in 1995. The covered cultivars, especially Robust, had higher initial FFA and lipase activity even though WHB had higher lipid content. FFA decreased in the Robust barley during storage and increased in the Bowman and WHB stored at 13% moisture and 25 ^oC after six months. TBA-MDA increased in all cultivars up to six months then decreased. It appears that the WHB cultivars may be more susceptible to storage problems under poor conditions, but this appear to be moderated by the actual cultivar grown. The cultivar Bob stored better than Rowax or 'Wanubet'. Thus, potential for improved types does exist.

Accelerated Storage of Barley Flours and Flakes

'Merlin' waxy hull-less barley was obtained from Barkley Seed/Western Plant Breeders (Fargo, ND) and milled at Roman Meal (Fargo, ND) to produce five flours varying in lipid and fiber content. The flours and a steam-rolled barley flake were stored at 37 ^oC for 12 weeks to accelerate lipid degradation and at 4 and 25 ^oC for 52 weeks for comparison. Lipid degradation was monitored by analysis of FFA and MDA content. All of the samples had the greatest increase in FFA when stored at 25 ^oC. The pearlings had the highest FFA content followed by the whole-grain meal, pearled flours, and flakes. MDA content increased until 44 weeks of storage at 25 ^oC and 4 ^oC, then decreased. A rancid odor was detected in all treatments stored at 25 ^oC at 44 and 52 weeks except the pearlings. No rancidity was detected in the samples stored at 4 ^oC. Changes in the samples stored at 37 ^oC did not correspond to changes detected in samples stored at 25 ^oC suggesting a higher temperature is required for accelerated storage studies.

Barley -glucan as a Fat Replacement Ingredient

A whole-grain WHB flour containing 6% -glucan (6.3% soluble fiber) and a pearled-sieved WHB flour containing 9% -glucan (9.8% soluble fiber) were substituted at the 50% level for all-purpose white flour in muffins made with three levels of oil, 0, 5.4%, and 10.7% (typical). In a standard muffin, volume decreases and hardness increases as oil is removed. In contrast, volume increased and hardness decreased as oil was removed from the barley flour muffins. A muffin containing whole-grain WHB flour and no oil had a volume and hardness similar to the all-purpose muffin containing 10.7% oil. This indicates that barley flour containing viscous -glucan can be used as a fat replacement ingredient.

Barley as a Rice Adjunct

Barley is being utilized as a rice adjunct for human consumption in Asian countries. The barley is pearled longitudinally, split, and pearled again to produce a 'rice-like' grain. The barley must have a white endosperm and remain whole during pearling. Whiteness (L-value) of 117 pearled barley samples ranged from 66.5 to 79.3 (rice=82). After cooking, rice typically sits in a steamer for up to an hour before eating and whiteness decreases (L=72). Cooked barley samples ranged from L=47.4 to 61.1 after sitting for 1 hr. Cultivars having the highest L-value after cooking were covered types that did not pearl well. This suggests that these cultivars may be utilized by plant breeders to incorporate the whiteness characteristic into the cultivars that pearl will.

We would like to thank Dr. Richard Horsley and his research group for providing the grain samples used in the grain storage studies.