Glycemic Response to Oat Bran Muffins Treated to Vary Molecular Weight of β‐Glucan

Oat bran muffins, containing 4 or 8 g of β‐glucan per two‐muffin serving, were prepared with or without β‐glucanase treatment to produce a range of β‐glucan molecular weights from 130,000 to just over 2 million. Following an overnight fast, the glycemic responses elicited by the untreated and treated muffins was measured in 10 healthy subjects and compared with a control whole wheat muffin. Taken all together, the 4‐g β‐glucan/serving muffins reduced blood glucose peak rise (PBGR) by 15 ± 6% compared with the control. The 8‐g β‐glucan/serving muffins had a significantly greater effect (44 ± 5% reduction compared with the control, P < 0.05). The efficacy of the muffins decreased as the molecular weight was reduced from a 45 ± 6% reduction in PBGR (P < 0.05) for the untreated muffins (averaged of both serving sizes) to 15 ± 6% (P < 0.05) for muffins with the lowest molecular weight. As the molecular weight was reduced from 2,200,000 to 400,000, the solubility of the β‐glucan increased from a mean of 44 to 57%, but as the molecular weight was further decreased to 120,000, solubility fell to 26%. There was a significant correlation (r² = 0.729, P < 0.001) between the peak blood glucose and the product of the extractable β‐glucan content and the molecular weight of the β‐glucan extracted.     

Effect of Cooking and Storage on the Amount and Molecular Weight of (1→3)(1→4)-β-d-Glucan Extracted from Oat Products by an In Vitro Digestion System

The extractability and molecular weight of β-glucan in oat bran, oat bran muffins, and oat porridge and the changes taking place during processing and storage were studied. The β-glucan was extracted using hot water and a thermostable α-amylase and by an in vitro system that simulated human digestion. Molecular weight (MW) of the extracted β-glucan was determined using high-performance size-exclusion chromatography. Hot-water treatment extracted 50–70% of total β-glucan in oat bran samples and rolled oats. The chromatographic peak MW of extracted β-glucan was in the 1.4–1.8 × 10⁶ range. Using the in vitro digestion system, 12–33% of total β-glucan in bran and rolled oats was solubilized, and peak MW was in the same range as β-glucan extracted by hot-water treatment. In muffins, 30–85% of total β-glucan was solubilized by in vitro digestion, with a major difference in extractability among muffins from different recipes. Peak MW of extracted β-glucan was lower in all muffins when compared to original bran. During frozen storage, extractable β-glucan decreased by >50% in all muffins, but no change in peak MW of extracted β-glucan was detected.     

Glycemic Response to Extruded Oat Bran Cereals Processed to Vary in Molecular Weight

Oat β‐glucan enriched extruded cereals with molecular weights (MWs) ranging from 2,180,000 to 326,000 were produced. Test meals composed of 31 g of available carbohydrate, 8.3–8.7 grams of β‐glucan, and milk were administered to subjects and their postprandial blood glucose levels monitored for 2 hr. White bread plus milk and a control wheat bran cereal plus milk were administered, and white bread alone served as a reference food for estimation of glycemic index (GI) of the cereals, after adjusting for the effect of adding milk to white bread. Both oat bran and wheat bran cereals significantly reduced peak blood glucose rise (PBGR) and area under the curve (AUC) versus white bread alone or white bread plus milk. There was a significant inverse relationship between AUC and log₁₀[weight average MW] (r² = 0.96, P = 0.0192). There was a significant inverse relationship between PBGR and log₁₀[viscosity] of in vitro extracts from all cereals, including the wheat control (r² = 0.96, P = 0.0031). However, no significant differences in glycemic responses among the oat bran cereals were found with pairwise comparisons. All cereals were low GI (<55) and were significantly lower than white bread alone or white bread plus milk. Among the oat bran cereals, palatability was positively correlated with MW (r² = 0.98, P = 0.0110).     

Molecular Weight Distribution of (1→3)(1→4)-β-Glucan Affects Pasting Properties of Flour from Oat Lines with High and Typical Amounts of β-Glucan

Experimental (N979-5-2-4 and IA95111) and traditional oat lines (Jim and Paul) with average %β-glucan of 7.5, 7.8, 4.9, and 4.4%, respectively, were grown in 2002, 2003, and 2004. Molecular weight (MW) distributions of the β-glucans were examined for potential variations among growing years and for relationships with pasting properties measured by Rapid ViscoAnalyser under three separate conditions: 1) in silver nitrate (SN) solution to inactivate enzymes; 2) hydrolyzed by α-amylase to eliminate the effect of starch; and 3) treated with lichenase to remove β-glucan. The β-glucan was extracted by a process involving multiple precipitation and dialysis steps, and the MW distributions were determined by HPLC. %β-Glucan in N979-5-2-4 and IA95111 lines were consistently and significantly greater (P < 0.05) than in Jim and Paul lines during three growing years. The contribution of β-glucan to peak viscosity on the RVA was substantially greater than that of the starch for all three years. The molecular number average and peak MW of β-glucan from N979-5-2-4 and IA95111 were greater than these values for Jim and Paul, and values were consistent among years. The MW of extracted β-glucan was associated with pasting properties after amylase hydrolysis, but not after treatment with lichenase or in SN solution.     

Comparisons of β-Glucan Content of Barley and Oat

The cholesterol-lowering effect of cereal grains has been associated with the soluble fiber component of dietary fiber. β-Glucan is the major soluble fiber component of barley (Hordeum vulgare L.) and oat (Avena sativa L.). Much research has been conducted to determine the β-glucan content of barley and oat genotypes from many different countries. However, genotypes of both crops always were grown in separate experiments, making direct comparisons between the two crops difficult. This study compares in the same experiment the β-glucan content of nine barley and 10 oat genotypes grown at two locations in each of two years (i.e., four environments) in North Dakota. Averaged across genotypes, total β-glucan content of barley and oat groat was similar. Soluble β-glucan content of oat groat was greater than barley, and oat groat had a greater ratio of soluble-to-total β-glucan than barley. The soluble β-glucan content and ratio of soluble to total β-glucan content of the “best” barley genotypes were less than that of oat genotypes with the highest levels of these two traits.     

Molecular Weight Distribution and (1→3)(1→4)-β-d-Glucan Content of Consecutive Extracts of Various Oat and Barley Cultivars

The content and molecular weight (MW) of β-glucan in extracts from a selection of oat and barley cultivars were compared using flow-injection analysis and high-performance size-exclusion chromatography. From 60 to 75% of the β-glucan was extracted from oat and waxy barley by hot water (90°C) containing heat-stable α-amylase, whereas just 50–55% was extracted from nonwaxy barley. Consecutive extractions with hot water and dimethylsulfoxide (DMSO) extracted 65% (nonwaxy barley) or 75–80% (oat and waxy barley) of the total β-glucan. An extraction with sodium hydroxide and sodium borohydride (NaOH/NaBH₄) increased the percentage of β-glucan extracted to 86–100% but decreased the MW. The MW of β-glucan in the oat cultivars selected was significantly higher than those in the barley cultivars. The β-glucan extracted from the nonwaxy barley cultivars showed significantly higher peak MW than that from the waxy barley cultivars.     

Serum Lipids in Hypercholesterolemic Men and Women Consuming Oat Bran and Amaranth Products

One hundred‐eighty hypercholesterolemic subjects following the National Cholesterol Education Program Step One Diet were randomly divided into six groups (30 ± 2/group). Group 1 served as the control and received no fiber supplements. The fiber supplemented groups received 50 g/day of oat bran or amaranth from various sources: Group 2 (oat bran muffins); Group 3 (amaranth muffins); Group 4 (Oat Bran O's); Group 5 (Oat Bran Flakes); and Group 6 (a variety of oat bran products). Fasting serum total cholesterol (FSTC), low density‐, very low density‐, and high density‐lipoprotein cholesterol (LDL‐C, VLDL‐C, and HDL‐C) and serum triacylglycerols were measured before and after the 28‐day intervention. Three‐day diet records were completed before and after intervention. Subjects reduced (P < 0.05) the mean intake of total and saturated fat, and cholesterol. FSTC dropped more than twice as much (P < 0.05) as was observed with fat modification alone (Group 1 = ‐0.31 mmol/L), when oat bran was provided as flakes (Group 5 = ‐0.86 mmol/L) or in a variety of forms (Group 6 = ‐0.75 mmol/L). If the initial ratio of HDL‐C to FSTC was low, then supplementation did not decrease FSTC to the extent observed when the initial ratio was high. Compliance with the dietary interventions was best when the subjects gave the product a rating of ≤2.0 (on a 1–4 hedonic scale, with 1 being excellent). We can conclude from these data that fiber supplementation to reduce serum cholesterol is most effective in hypercholesterolemic individuals that have a greater proportion of HDL‐C. In addition, not all the oat bran products evaluated were able to lower cholesterol to the same extent, indicating that the ability of soluble fiber to reduce FSTC can be compromised by other dietary factors such as insoluble fiber.     

Intestinal Contents Supernatant Viscosity of Rats Fed Oat-Based Muffins and Cereal Products

The intestinal contents viscosities of oat-based breakfast cereals and muffins were examined. Male Sprague-Dawley rats were adapted for four days to a semipurified diet (AIN-76A). Following an overnight fast, the animals were meal-fed 5 g of either the AIN-76A diet (containing 5% cellulose), the AIN-76A diet containing 2% guar gum, whole-grain oat flour, one of five cereals (corn flakes, cooked oatmeal, uncooked oatmeal, cooked oat bran, or Cheerios), or one of two types of muffins (containing whole-grain oat flour or oatmeal). Two hours after presentation of the meal, the animals were killed, the small intestines removed, and the contents collected. The contents were centrifuged, and the viscosity values of the undiluted supernatants were determined. The supernatant viscosity from rats fed the AIN-76A diet was negligible (<5 mPa·sec), whereas that from rats fed guar gum was high (396 ± 117 mPa·sec). Of the cereals fed, corn flakes resulted in the lowest viscosity (<5 mPa·sec). However, all oat-based cereals resulted in high intestinal contents supernatant viscosity levels (cooked oatmeal 368 ± 128, uncooked oatmeal 307 ± 107, cooked oat bran 301 ± 85, Cheerios 199 ± 58, mPa·sec) with no statistically significant differences. The intestinal contents viscosity values for the whole-grain oat flour muffin and oatmeal muffin were 233 ± 52 and 111 ± 26 mPa·sec, respectively, a statistically significant difference (P < 0.05). This suggests that the form of the oat within a food may influence the degree of viscosity produced within the small intestine after that food is consumed.     

Effects of Different Cereal Fibers on Cholesterol and Bile Acid Metabolism in the Syrian Golden Hamster

This study examined the effects of various cereal fibers and various amounts of β-glucan on cholesterol and bile acid metabolism. Hamsters were fed semisynthetic diets containing 0.12% cholesterol, 20% fat, and either 16% total dietary fiber (TDF) from wheat bran (control) or 10% TDF from oat bran, 13% TDF from oat bran concentrate or barley grains, 16% TDF from oat fiber concentrate, barley flakes, or rye bran. After five weeks, plasma total cholesterol and liver cholesterol concentrations were significantly lower (20 and 50%, respectively) only in hamsters fed rye bran. Diets containing any of the oat ingredients or barley had no effect on total cholesterol. Changes in the pattern of biliary bile acids occurred in hamsters fed 16% TDF from barley flakes or 10% TDF from oat bran. Hamsters fed rye bran had a significantly higher fecal bile acid excretion when compared with controls fed wheat bran. Because rye bran caused the most pronounced lowering effect of total cholesterol despite the lowest content of β-glucan and soluble fibers, components other than β-glucan and soluble fibers seem to be involved in its hypocholesterolemic action. Since the effects of the oat and barley ingredients were not solely correlated to the β-glucan content, structural changes occurring during processing and concentrating of the products may have impaired the hypocholesterolemic potential of the β-glucans, and other factors such as solubility and viscosity of the fiber components seem to be involved.     

Structure and Physicochemical Properties of Starches from Sieve Fractions of Oat Flour Compared with Whole and Pin-Milled Flour

One oat cultivar grown in Idaho (three field sites) was pin-milled and separated by sieving to investigate whether starch from oat bran differs from the remainder of kernel. Ground oat particles were classified into three sieve fractions: 300–850 μm, 150–300 μm and <150 μm). β-Glucan content in sieve fractions was analyzed and starch was extracted from kernels without milling and from kernels of each sieve fraction. β-Glucan contents of 300–850, 150–300, and <150 μm sieve fractions were 4.2, 2.3, and 0.8%, respectively. Therefore, starch in bran (300–850 μm sieve fraction) and endosperm (<150 μm sieve fraction) were separated. Starch isolated from entire kernels had significantly higher apparent and absolute amylose content than starch from the 300–850 μm sieve fraction. Starch from different sieve fractions was not significantly different in the apparent amylose, absolute amylose, amylopectin molecular weight, gyration radii, starch gelatinization, and amylose-lipid complex thermal transition temperatures. Starch from the 150–300 μm sieve fraction had significantly lower peak, final, and setback viscosity compared with the starch isolated from the 300–850 μm and <150 μm sieve fractions. Starch removed from the oat bran fraction during β-glucan enrichment may have different applications compared with starch obtained from other kernel compartments. Because pin-milling decreased apparent amylose content and shortened amylopectin branch chains, its potential to alter starch structure should be considered.     

Rheological Properties of (1→3),(1→4)-β-d-Glucans from Raw,Roasted, and Steamed Oat Groats

Effects of hydrothermal treatments (steaming, roasting) of oat grain on β-glucan extractability and rheological properties were tested on oat cultivars with low (Robert) and high (Marion) β-glucan content. Steaming of grain reduced the amount of β-glucan that could be extracted, compared with raw or roasted grain, but the extracts from steamed grain had much greater viscosity. Increased extraction temperatures increased the amount and the average relative molecular mass (M _r) value of β-glucan extracted. In boiling water extractions, the average M _r values among raw, roasted and steamed oat samples were equivalent, but extracts from steamed oat grain had significantly higher intrinsic viscosity than the extracts from roasted or raw oat grains. β-glucan solutions purified from steamed grain extracts were very viscous and highly pseudoplastic, as described by the power law equation. Oat β-glucan from steamed samples were more viscoelastic than β-glucan from roasted or raw oat samples. Because viscous properties of β-glucan from boiling water extracts are influencedhydrothermal treatments without affecting polymer molecular weight, polymer interaction with the solvent must be affected. Steaming may disrupt intramolecular cross-linkings in native β-glucan, allowing a linear chain configuration to generate greater viscosity.     

Molecular Weight Distribution of β‐Glucan in Oat‐Based Foods

Oats, different oat fractions as well as experimental and commercial oat‐based foods, were extracted with hot water containing thermostable α‐amylase. Average molecular weight and molecular weight distributions of β‐glucan in extracts were analyzed with a calibrated high‐performance size‐exclusion chromatography system with Calcofluor detection, specific for the β‐glucan. Oats, rolled oats, oat bran, and oat bran concentrates all had high Calcofluor average molecular weights (206 × 10⁴ to 230 × 10⁴ g/mol) and essentially monomodal distributions. Of the oat‐containing experimental foods, extruded flakes, macaroni, and muffins all had high average molecular weights. Pasteurized apple juice, fresh pasta, and teacake, on the other hand, contained degraded β‐glucan. Calcofluor average molecular weights varied from 24 × 10⁴ to 167 × 10⁴ g/mol in different types of oat bran‐based breads baked with almost the same ingredients. Large particle size of the bran and short fermentation time limited the β‐glucan degradation during baking. The polymodal distributions of β‐glucan in these breads indicated that this degradation was enzymatic in nature. Commercial oat foods also showed large variation in Calcofluor average molecular weight (from 19 × 10⁴ g/mol for pancake batter to 201 × 10⁴ g/mol for porridge). Boiling porridge or frying pancakes did not result in any β‐glucan degradation. These large differences in molecular weight distribution for β‐glucan in different oat products are very likely to be of nutritional importance.     

Composition of Oat Bran and Flour Prepared by Three Different Mechanisms of Dry Milling

Three mechanisms of oat milling were tested for laboratory-scale oat bran production. Oat bran consistent with AACC definition and commercially obtained product was generated with either roller-milling or impact-milling of groats, followed by sieving to retain larger particles. These bran preparations were enriched ≈1.7-fold in β-glucan and ash, 1.4-fold in protein, and 1.1-fold in lipid. Bran finishing made further enrichments in protein, β-glucan, and ash. Tempering oat (to 12% moisture for 20 min) improved bran yield from roller-milling nearly two-fold but had little effect on bran composition. Bran yield from the impact-type mill was significantly affected by grinding screen size. Oat bran obtained from a pearling mill was only slightly enriched in β-glucan and protein, but it was more heavily enriched in ash and oil than brans from roller or impact mills. The pearling mill isolated the outer layers of the groat directly, but because of its low β-glucan composition it did not meet the AACC definition of oat bran, indicating a relatively uniform distribution of β-glucan in the groat.     

Molecular Weight of β‐Glucan Affects Physical Characteristics,In Vitro Bile Acid Binding,and Fermentation of Muffins

Muffins containing different amounts and molecular weights (MW) of β‐glucan were evaluated for the effect of β‐glucan on the physical characteristics of the muffins and on in vitro bile acid binding and fermentation with human fecal flora. Wheat flour muffins were prepared with the addition of β‐glucan extracts with high‐, medium‐, or low‐MW. For oat flour muffins, the native oat flour contained high‐MW β‐glucan; the oat flours were treated to create medium‐ and low‐MW β‐glucan within the prepared muffin treatments. For each 60‐g muffin, the amounts of β‐glucan were 0.52, 0.57, and 0.59 g for high‐, medium‐, and low‐MW β‐glucan wheat flour muffins, and 2.38, 2.18, and 2.23 g for high‐, medium‐, and low‐MW β‐glucan oat flour muffins, respectively. The lower the MW of the β‐glucan in muffins, the lower the height and volume of the muffins. The oat flour muffins were less firm and springy than the wheat flour muffins as measured on a texture analyzer; however, MW had no effect on muffin texture. The oat flour muffins bound more bile acid than did the wheat flour muffins. The muffins with high‐MW β‐glucan bound more bile acid than did those with low‐ and medium‐MW β‐glucan. Muffin treatment affected the formation of gas and total short‐chain fatty acids (SCFA) compared with the blank without substrate during in vitro fermentation. There were no differences in pH changes and total gas production among muffin treatments. The high‐MW β‐glucan wheat flour muffins produced greater amounts of SCFA than did the wheat flour muffin without β‐glucan and the oat flour muffins; however, there were no differences in SCFA production among muffins with different MW. In general, the β‐glucan MW affected the physical qualities of muffins and some potential biological functions in humans.     

Optimizing the molecular weight of oat β-glucan for in vitro bile acid binding and fermentation

A previous study showed β-glucan with low molecular weight (MW, 1.56×10(5) g/mol) bound more bile acid and produced greater amounts of short-chain fatty acids (SCFA) than did β-glucan with high MW (Mn=6.87×10(5) g/mol). In the current study, β-glucan extracted from oat flour was fractionated into six different MW levels (high MW, 7.09×10(5); low level 1 (L1), 3.48×10(5); L2, 2.42×10(5); L3, 1.61×10(5); L4, 0.87×10(5); and L5, 0.46×10(5) g/mol) and evaluated to find the optimum MW affecting in vitro bile acid binding and fermentation. The β-glucan fractions with 2.42×10(5)-1.61×10(5) g/mol (L2 and L3) bound the greatest amounts of bile acid. After 24 h of fermentation, no differences were found in total SCFA formation among L1, L2, L3, and L4 fractions; however, the high MW and L5 MW fractions produced lower amounts of total SCFA. Thus, the optimum MW of β-glucan to affect both hypocholesterolemic and antitumorigenic in vitro effects was in the range of 2.42×10(5)-1.61×10(5) g/mol. This MW range also was the most water-soluble among the MWs evaluated.     

The Potential of Hull-less Barley

Hull-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 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 β-glucan 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.     

氮、磷肥对裸燕麦子粒产量和β-葡聚糖含量的影响

以裸燕麦青永久887(Avena nuda L. cv. Qingyongjiu No.887)为材料,研究了施氮和施磷对子粒产量与β-葡聚糖含量的影响;分析了N、P肥对裸燕麦子粒产量构成因素,穗数、穗粒数、穗粒重、千粒重的影响,并进行了经济效益分析。结果表明,裸燕麦穗数、穗粒数、穗粒重、千粒重及子粒产量,随施氮量的增加呈先增后降变化趋势;随施磷量的增加而增加。β-葡聚糖含量随施氮或施磷量的增加而增加。在N 90 kg/hm2、P2O5 90 kg/hm2处理下,裸燕麦穗数、穗粒数、穗粒重、千粒重、子粒产量均达最高值;在N 135kg/hm2、P2O5 90 kg/hm2处理,裸燕麦子粒β-葡聚糖含量最高。经济效益分析表明,经济施肥量为:N 90 kg/hm2、P2O5 90 kg/hm2。裸燕麦子粒产量Y (kg/hm2),可用其与N (kg/hm2)和P (P2O5,kg/hm2)肥间的二元二次回归方程估测。     

In vitro digestion rate and estimated glycemic index of oat flours from typical and high β-glucan oat lines

The in vitro starch digestion rate and estimated glycemic index (GI) of oat flours and oat starches from typical and high β-glucan oat lines were evaluated along with the impact of heating on starch digestion. Flour from oat lines ('Jim', 'Paul', IA95, and N979 containing 4.0, 5.3, 7.4, and 7.7% β-glucan, respectively) was digested by pepsin and porcine pancreatin. To determine the impact of heating on starch digestion, oat slurries were prepared by mixing oat flour and water (1:8 ratio) and heating for 10 min prior to digestion. Viscosity, as measured on a Rapid Visco Analyzer, increased with increases in concentration and molecular weight of β-glucan. The in vitro starch digestion of oat flours and a control, white bread made from wheat flour, increased as the digestion time increased. Starch digestion of oat flour was slower than that of the control (p < 0.05). Heat treatment of oat-flour slurries increased the starch digestion from a range of 31-39% to a range of 52-64% measured after 180 min of in vitro digestion. There were no differences in starch digestibility among oat starches extracted from the different oat lines. The GI, estimated by starch hydrolysis of oat flours, ranged from 61 to 67, which increased to a range of 77-86 after heating. Oat-flour slurries prepared from IA95 and N979 lines with high β-glucan concentrations had lower GI values than did slurries made from Jim and Paul lines. Starch digestion was negatively correlated with β-glucan concentrations in heated oat-flour slurries (R(2) = 0.92). These results illustrate that the oat soluble fiber, β-glucan, slowed the rate of starch digestion. This finding will help to develop new food products with low GI by using oat β-glucan.     

Hypoglycemic effects and biochemical mechanisms of oat products on streptozotocin-induced diabetic mice

Oat products are abundant in β-glucan, which could lower the glycemic index of products or foods. A low glycemic index is beneficial in the control of postprandial glycemia. The study examined the hypoglycemic effects of oat products that had the same percentage of oat β-glucan and were added into the diet fed to streptozotocin-induced diabetic mice for 6 weeks, and potential mechanisms are discussed here. Oat products significantly decreased fasting blood glucose and glycosylated serum protein (p < 0.05), but the hypoglycemic effect was not more than that of metformin (p > 0.05). Oat products increased glycogen, hormone, and nuclear receptor levels (p < 0.05), decreased free fatty acid content and succinate dehydrogenase activity (p < 0.05), and inhibited pancreatic apoptosis (p < 0.05). The results showed oat products had hypoglycemic effects. Hypoglycemic effects of oat products might be regulating glucose and fat metabolisms, stimulating hormone secretion, activating the nuclear receptor, and protecting organ function.     

Textural and Bile Acid‐Binding Properties of Muffins Impacted by Oat β‐Glucan with Different Molecular Weights

Water‐soluble β‐glucan (BG) extracted from a high‐BG oat line was treated with different amounts of lichenase (1→3)(1→4)‐β‐d ‐glucanase) enzyme to yield three different molecular weight (MW) BG extracts. Low (LMW‐BG, 157,000), medium (MMW‐BG, 277,000), and high (HMW‐BG, 560,000) MW BG extracts were added to plain muffin formulations at a level of 0.52% (0.42% in the batter, 0.52% in the resultant muffins) to investigate the effect of MW of BG on textural and bile acid (BA) binding properties of the muffins. In addition, treatments were prepared containing LMW‐BG, MMW‐BG, and HMW‐BG extracts in amounts providing equivalent batter firmness as determined on a texture analyzer. Resultant BG concentrations (and per serving amounts) of these muffins were 1.36% (0.81 g/60 g muffin), 1.05% (0.63 g/60 g muffin), and 0.52% (0.31 g/60 g muffin), respectively; thus, the LMW treatment complied with a U.S. Food and Drug Administration health claim requiring 0.75 g of BG per serving. The firmness, springiness, and BA‐binding capacity of the muffins were unaffected by the MW of BG. However, when added at the maximum limit for equivalent batter firmness, the LMW treatment was more firm and less springy than the HMW treatment. Furthermore, BA‐binding capacities of LMW and MMW fractions tended to be greater than that of the HMW fraction when added at the maximum limit. These results add further evidence to the importance of fine‐tuning BG structure to provide maximum health benefits while maintaining high product quality.