Supercritical fluid extraction of alkylamides from Echinacea angustifolia

Echinacea has been known for its immunostimulatory activity, and its alkylamide components have been linked to such biological activity. Consequently, alkylamides in Echinacea angustifolia were extracted using supercritical carbon dioxide from fresh and dried roots at 45-60 degrees C and 34-55 MPa, and the alkylamide yield in the extracts was determined. The yield of alkylamides from fresh roots increased with temperature yet decreased with pressure, whereas the yield from air-dried roots (moisture content 8.4%) increased with both temperature and pressure. Freeze-drying of the roots to a moisture content of 4.9% did not result in any further increase in the yield compared to that of air-dried roots. Alkylamide yield of the ground dried roots extract was the highest (p < or = 0.05) among those from fresh, ground and unground E. angustifolia roots. Supercritical fluid extraction therefore shows potential for the recovery of alkylamides from dried Echinacea roots.     

Effect of Formulation and Processing Treatments on Viscosity and Solubility of Extractable Barley β‐Glucan in Bread Dough Evaluated Under In Vitro Conditions

β‐Glucan shows great potential for incorporation into bread due to its cholesterol lowering and blood glucose regulating effects, which are related to its viscosity. The effects of β‐glucan concentration, gluten addition, premixing, yeast addition, fermentation time, and inactivation of the flour enzymes on the viscosity of extractable β‐glucan following incorporation into a white bread dough were studied under physiological conditions, as well as, β‐glucan solubility in fermented and unfermented dough. β‐Glucan was extracted using an in vitro protocol designed to approximate human digestion and hot water extraction. The viscosity of extractable β‐glucan was not affected by gluten addition, the presence of yeast, or premixing. Fermentation produced lower (P ≤ 0.05) extract viscosity for the doughs with added β‐glucan, while inactivating the flour enzymes and increasing β‐glucan concentration in the absence of fermentation increased (P ≤ 0.05) viscosity. The physiological solubility of the β‐glucan concentrate (18.1%) and the β‐glucan in the unfermented dough (20.5%) were similar (P > 0.05), while fermentation substantially decreased (P ≤ 0.05) solubility to 8.7%, indicating that the reduction in viscosity due to fermentation may be highly dependent on solubility in addition to β‐glucan degradation. The results emphasize the importance of analyzing β‐glucan fortified foods under physiological conditions to identify the conditions in the dough system that decrease β‐glucan viscosity so that products with maximum functionality can be developed.     

Network Formation by Pilot Plant and Laboratory‐Extracted Barley β‐Glucan and Its Rheological Properties in Aqueous Solutions

Barley and oat β‐glucans of low viscosity form reversible gels when prepared in sufficiently high concentrations. Solutions of three barley β‐glucan gums differing in molecular weight and thus in viscosity were prepared at 1.0, 2.5, or 5.0% (w/w) concentration levels. Medium‐ and high‐viscosity gums were prepared in a pilot plant (PP) and laboratory (LAB), respectively. Low‐viscosity (LV) gum was extracted in the laboratory at pH 7, which allowed for native enzymatic activity and decreased molecular weight. Network formation was monitored overnight through changes in storage (G′) and loss (G″) moduli. The strength of the formed network was determined from oscillatory rheological measurements by increasing the strain from 2 to 100%. Findings demonstrate that gelation of β‐glucan is molecular weight dependent and practically an instantaneous process for low‐viscosity gum solutions at concentrations of ≤5% gum (or ≤4% β‐glucan), levels lower than previously anticipated. The purity of β‐glucan also seems to affect gelation rate. Better understanding of the β‐glucan gelation behavior is important for its functionality in both food product applications and physiological mechanisms of its health benefits.     

Viscosity and Solubility of β‐Glucan Extracted Under In Vitro Conditions from Barley β‐Glucan‐Fortified Bread and Evaluation of Loaf Characteristics

Fortifying bread with β‐glucan has been shown to reduce bread quality and the associated health benefits of barley β‐glucan. Fortification of bread using β‐glucan concentrates that are less soluble during bread preparation steps has not been investigated. The effects of β‐glucan concentration and gluten addition on the physicochemical properties of bread and β‐glucan solubility and viscosity were investigated using a less soluble β‐glucan concentrate, as were the effects of baking temperature and prior β‐glucan solubilization. Fortification of bread with β‐glucan decreased loaf volume and height (P ≤ 0.05) and increased firmness (P ≤ 0.05). Gluten addition to bread at the highest β‐glucan level increased height and volume (P ≤ 0.05) to values exceeding those for the control and decreased firmness (P ≤ 0.05). β‐Glucan addition increased (P ≤ 0.05) extract viscosity, as did gluten addition to the bread with the highest β‐glucan level. Baking at low temperature decreased (P ≤ 0.05) β‐glucan viscosity and solubility, as did solubilizing it prior to dough formulation. Utilization of β‐glucan that is less soluble during bread preparation may hold the key to effectively fortifying bread with β‐glucan without compromising its health benefits, although more research is required.     

Effect of Health Information on Consumer Acceptability of Bread Fortified with β‐Glucan and Effect of Fortification on Bread Quality

Fortifying bread with β‐glucan reduces bread sensorial properties, though fortification using β‐glucan concentrates of low solubility under the conditions of dough preparation has not been investigated. This study investigated the consumer acceptability and purchase intent of bread fortified with a less soluble β‐glucan concentrate at levels corresponding to 0, 0.75, and 1.5 g β‐glucan/serving bread in relation to the provision of health information, gender, and whole wheat bread consumption. The effect of β‐glucan concentration on the physical properties of the bread produced under pilot plant settings was also investigated. β‐Glucan addition decreased (P < 0.05) loaf volume, increased firmness, and produced a darker, redder bread (P < 0.05), though fortification at 1.5 g β‐glucan/serving bread decreased height as well (P < 0.05). Consumer evaluation (n = 122) revealed that health information increased liking of appearance, flavor, and overall acceptability of the 1.5 g/serving bread to levels similar to or exceeding that of the control. Liking of the 1.5 g β‐glucan/serving bread appearance increased more in women than in men and for consumers who regularly consumed whole wheat bread for perceived health benefits when β‐glucan health information was provided. The provision of β‐glucan health information may be the key to increasing consumer acceptability of bread fortified with β‐glucan.     

Analysis of phenolic acids in barley by high-performance liquid chromatography

Phenolic acids from 30 barley varieties (combination of hulled/hulless/two-row/six-row/regular/waxy) were investigated by HPLC following four different sample treatments: (a) simple hot water extraction, (b) extraction after acid hydrolysis, (c) acid plus alpha-amylase hydrolysis, and (d) acid plus alpha-amylase plus cellulase hydrolysis treatments. The benzoic acid (p-hydroxybenzoic, vanillic, and protocatechuic acids) and cinnamic acid derivatives (coumaric, caffeic, ferulic, and chlorogenic acids) were identified, and some of the phenolic acids were quantified after each above-mentioned treatment. The data indicated that a combination of sequential acid, alpha-amylase, and cellulase hydrolysis treatments might be applicable for release of more phenolic acids from barley.     

Development of an Orange‐Flavored Barley β‐Glucan Beverage

Barley β‐glucan concentrate shows great potential as a functional food ingredient, but few product applications exist. The objectives of this study were to formulate a functional beverage utilizing barley β‐glucan concentrate, and to make a sensory evaluation of beverage quality in comparison to pectin beverages and to assess shelf stability over 12 weeks. Three beverage treatments containing 0.3, 0.5, and 0.7% (w/w) barley β‐glucan were developed in triplicate. Trained panelists found peely‐ and fruity‐orange aroma and sweetness intensity to be similar (P > 0.05) for all beverages tested. Beverage sourness intensity differed among beverages (P ≤ 0.05). Panelists evaluated beverages containing 0.3% hydrocolloid as similar (P > 0.05), whereas beverages with 0.5 and 0.7% β‐glucan were more viscous (P ≤ 0.05) than those with pectin at these levels. Acceptability of beverages was similar according to the consumer panel. Shelf stability studies showed no microbial growth and stable pH for all beverages over 12 weeks. Colorimeter values for most beverages decreased (P ≤ 0.05) during the first week of storage, mostly stabilizing thereafter. With an increase in concentration, β‐glucan beverages became lighter in color (P ≤ 0.05) and cloudier, but these attributes for pectin beverages were not affected (P > 0.05). β‐Glucan beverages exhibited cloud loss during the first three weeks of storage. β‐Glucan can therefore be successfully utilized in the production of a functional beverage acceptable to consumers.     

Functionality of Barley Proteins Extracted and Fractionated by Alkaline and Alcohol Methods

This research optimized the extraction of different protein fractions from barley grains and assessed the physicochemical properties of the fractions obtained. Pearling was first used to remove the grain's outer layers (mainly bran and germ) so that the barley cytoplasmic proteins (albumin and globulin) would be enriched in the pearling flour (PF), while endosperm proteins (hordein and glutelin) would be enriched in the pearled grain flour (PGF). Salt, alcohol, and alkaline solutions were then used to extract different barley protein fractions from PF and PGF. The effects of extraction solvent type, pH, temperature, and extraction time on protein content and extraction efficiency were studied. Aqueous ethanol (55%, v/v) efficiently extracted barley hordein from PGF at 60°C, whereas pH 11.5 alkaline solution was the most efficient for extracting both cytoplasmic and endosperm proteins from barley PF and PGF at 23°C. Subunit molecular weight, amino acid composition, and the functional properties of each isolated barley protein fraction were investigated. Barley glutelin demonstrated superior oil‐binding property and emulsifying stability, whereas barley hordein exhibited good foaming capacity.     

Volatiles from roasted byproducts of the poultry-processing industry

Volatiles of roasted chicken breast muscle and byproducts, such as backbones, breastbones, spent bones, and skin, were investigated. Total volatile concentrations ranged from 2030 ppb in the roasted backbones to 4049 ppb in the roasted skin. The major classes of volatile compounds detected in roasted samples were aldehydes (648-1532 ppb) and alcohols (336-1006 ppb). Nitrogen- and/or sulfur-containing compounds were also detected in appreciable quantities (161-706 ppb) in all samples. For all samples, hexanal and 2-methyl-2-buten-1-ol were dominant among the aldehydes and alcohols, respectively. Among the nitrogen- and sulfur-containing compounds, Maillard reaction products, such as tetrahydropyridazines, piperidines, and thiazoles, were the major contributors to the total volatile content in all samples. The composition of volatiles observed in roasted byproducts was markedly different from that of the roasted breast muscle. Therefore, the blending of the byproducts in appropriate proportions or blending of volatile flavor extracts from different byproducts may be necessary to obtain an aroma that mimics roasted chicken aroma.     

Effect of Extraction Conditions on Yield,Composition, and Viscosity Stability of Barley β-Glucan Gum

Cereal β-glucan can function as a thickener, but endogenous β-glucanase enzymes of the grain cleave β-glucan, reducing its viscosity. Although different extraction techniques have been developed, the viscosity stability of β-glucan gum has not been reported. The objective of this study was to investigate the effect of extraction treatments on the yield, purity, and viscosity stability of barley β-glucan (BBG) gum. A regular barley cultivar, Condor, and a waxy cultivar blend were extracted at pH 7–10 and 55°C for 0.5 hr. Four extraction conditions were evaluated: 1) extraction at high pH with no additional heat treatment; 2) boiling of extract; 3) prior refluxing of flour with 70% ethanol; and 4) treatment of extract with thermostable α-amylase for purification. Viscosity of extracts was monitored for ≥24 hr at 25°C. The highest β-glucan purities were achieved with a boiled Condor extract at pH 7 (81.3% db, 4.1% yield) and with refluxed waxy barley extracted at pH 8 and treated with α-amylase and (79.3% db, 5.1% yield). Gums extracted without subsequent heat treatment or prior refluxing of flour had high protein (>17%) and starch (>24%) impurities, respectively. The viscosity of gums obtained without heating was unstable. Prior refluxing treatment was not sufficient to stabilize final extracts. Boiling extracts resulted in stable but low viscosity. Reflux followed by purification treatment produced the highest stable viscosity for 0.5% solutions of both Condor (64 mPa sec^-1, pH 7) and waxy (48.8 mPa sec^-1, pH 8) extracts. Stable BBG gum with high viscosity can be obtained using thermal treatments in combination with high pH. The potential use of such gums as thickeners in food systems needs to be assessed.