Cereal Chem. 76(5):589-599Hull-less barley (HB) has been investigated in many countries for use in feed, food, and industry since the publication of the last review in 1986. Literature published since 1990 on various aspects of HB utilization, other than in monogastric feeds, has been reviewed. Several HB cultivars containing low or high β-glucan, low or high extract viscosity, and waxy (0-5% amylose) or normal starch are now available. Interest in HB utilization in the food industry developed largely due to its high βglucan content, particularly in the waxy cultivars. β-Glucan is a major component of soluble fiber implicated in hypocholesterolemia, hypoglycemia, and in reducing incidence of chemically induced colon cancer in experimental animals. However, large-scale clinical trials using human subjects are needed to corroborate these effects. The zero amylose HB starch had low syneresis or a high freeze-thaw stability suitable for use in frozen foods. Single-or double-modified waxy HB starch may replace corn starch in some food applications, and cationized HB starch can replace corn and potato starches in the pulp and paper industry. HB may be milled using conventional wheat milling equipment to yield bran and flour for multiple food uses. Hull-less barley may also be used as a feed stock for fuel alcohol production, for the preparation of food malt with low or high enzyme activities, and for brewer's and distiller's malts.

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Six laboratory‐prepared (LM) and four commercially‐obtained (CM) samples of linseed meal were analyzed for eleven proximate components, ten mineral elements, monosaccharides, amino acids, and seven vitamins (two samples only). Analysis of variance of LM data showed location had a greater influence on meal composition than did cultivar. LM and CM had similar composition, except for protein, total carbohydrates, acid‐detergent fiber and lignin. Hull separated by a liquid cyclone process formed 37.5% of the seed and contained less than 1% oil, 20% protein and 32.9% total monosaccharides. Xylose and arabinose were the major sugars. Meal absorbed 8‐fold, and the hull 13‐fold their weights of water (water‐hydration capacity), compared to less than 2‐fold by similar fractions of canola (rapeseed) and soybean. Viscosities of aqueous extrats of hull were stable for 30 min at 25°C, and were concentration‐dependent.

Registered Canadian cultivars of flax, and laboratoryprepared and eommereially obtained samples of linseed meal (LM), were used to determine extract viscosity and mucilage, trypsin inhibitors and hydrocyanic acid (HCN) concentrations. The mucilage readily leached out from the seed coat (hull) fragments soaked in water, leaving behind pentagon-shaped cells that could be seen clearly in scanning electron micrographs. Extract viscosity significantly varied in the laboratory-prepared (23-48 cS) and commercially obtained (30-68 cS) samples of LM and may be used to obtain an indirect, qualitative estimate of flax mucilage. Mucilage was extracted from whole seed in 5.0-5.3% yields and contained 20-24% protein (about 10% ash and 30% total carbohydrates). Laboratory-prepared LM (raw) contained 42-51 units of trypsin inhibitor activity, commercially obtained samples, 14-37 units, and raw rapeseed and soybean meals, 99 and 1650 units, respectively. Picric acid tests (qualitative) showed only traces of HCN in ten cultivars of freshly ground flax. The acid silver nitrate titration procedure measured HCN quantitatively, but showed its presence only in three of the five cultivars investigated. HCN was conveniently measured by a colorimetric procedure (barbituric acidpyridine reaction), which may be used to screen flax cultivars. HCN content of flax was significantly influenced by environments (growth location and season) and, to a less extent, by cultivar.

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