Textural Comparisons of Gluten‐Free and Wheat‐Based Doughs,Batters, and Breads

Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.     

REVIEW: Effects of Germination on the Nutritional Profile of Gluten‐Free Cereals and Pseudocereals: A Review

There are a growing number of individuals diagnosed with food allergies and intolerances. Gluten, in particular, is avoided by many individuals because of celiac disease, gluten intolerance, and gluten ataxia. Individuals with allergies, intolerances, or both follow strict diets, but there is concern that these individuals may be at risk of several nutrient deficiencies, including decreased calcium, iron, B vitamins, and fiber. To prevent deficiencies, alternative sources of these nutrients must be provided. Gluten‐free cereals and pseudocereals such as amaranth, buckwheat, corn, millet, rice, sorghum, and quinoa can be excellent sources of vitamins, minerals, fiber, and other important nutrients. Germination of these edible seeds has been shown to further increase nutrient content and to reduce antinutrients. Their use to naturally fortify and enrich gluten‐free foods has great potential. Although there are many benefits to germinated seeds in food, more research must be done to improve texture and sensory properties to gain wider consumer acceptance. A review of germination of gluten‐free cereals and pseudocereals and its effect on their nutritional profile is presented.     

In Vitro Starch Digestibility of Gluten‐Free Spaghetti Based on Maize,Chickpea, and Unripe Plantain Flours

Gluten‐free and high indigestible carbohydrate food development is a topic that deserves investigation because of an increased focus on gluten intolerance and celiac disease and on metabolic disorders caused by overweight and obesity. Here, chickpea and maize flours were used as sources of protein and carbohydrate (because of the level used in the mixture) and unripe plantain as an indigestible carbohydrate source in composite gluten‐free spaghetti elaboration. The mixture of unripe plantain, chickpea, and maize was used at different levels to prepare spaghetti (samples S15Pla and S25Pla); control pasta was made of 100% semolina (S100Sem), and a 100% unripe plantain flour (S100Pla) pasta was also evaluated. In vitro amylolysis rate of fresh and stored (three and five days) spaghetti was assessed. The spaghetti with 100% unripe plantain (S100Pla) had higher resistant starch (RS) content than the control sample and the two cooked composite gluten‐free spaghettis (S15Pla, S25Pla), and RS further increased with the storage time. The plantain spaghetti (S100Pla) also had the highest rapidly digestible starch and the lowest slowly digestible starch contents; this pattern agrees with the hydrolysis rate, especially after cold storage. The stored S25Pla spaghetti showed the lowest hydrolysis rate and predicted glycemic index. Blending chickpea, maize, and unripe plantain flours represents a way to obtain gluten‐free spaghetti with high nondigestible carbohydrate content and slow digestion properties.     

Gluten Aggregation Behavior in High‐Shear‐Based GlutoPeak Test: Impact of Flour Water Absorption and Strength

Gluten aggregation behaviors of wheat flour were evaluated using a high‐shear‐based method with the GlutoPeak instrument and related to flour functional properties. GlutoPeak peak time (PT) and peak area (PA) were positively associated with gluten strength but negatively affected by farinograph absorption (FAB). GlutoPeak maximum torque (T _max) was highly positively (P < 0.001) correlated with FAB regardless of gluten strength. PT and PA increased with the decrease of FAB. This could result in overestimation of gluten strength owing to water absorption. To account for the impact of FAB, a new parameter GlutoPeak strength index (GSI) was introduced for predicting gluten strength. GSI was obtained by multiplying T _max and PA. This arithmetic product was found to provide greater correlation (r = 0.91) with dough strength than those of PA (r = 0.84) or PT (r = 0.57) based on the analysis of 56 advanced breeding lines with wide range of FAB. Moreover, significant relationships were found between GSI and flour mixing and baking properties. Using 8 g of flour and with a test time of less than 10 min, the GlutoPeak instrument shows great potential as a rapid tool for gluten strength selection.     

Accumulation of High‐Molecular‐Weight Glutenin Subunits in Superior and Inferior Grains of a Winter Wheat,Yangmai 158

The difference in accumulation of high‐molecular‐weight glutenin subunits (HMW‐GS) in superior (basal) and inferior (distal) grains results in the nonuniformity of grain quality in a winter wheat (Triticum aestivum L. ‘Yangmai 158’). The HMW‐GS accumulation and glutenin macropolymer (GMP) content were studied in superior and inferior grains during the grain‐filling period. Compared with inferior grains, HMW‐GS was formed earlier and total accumulation amount was higher in superior grains. The total HMW‐GS content was higher in superior grain than inferior grain, except at maturity. For individual HMW‐GS types, the accumulation and content of subunit 7 were the highest, followed by subunit 12, and those of subunit 8 were the lowest, followed by subunit 2 in superior grain. In contrast, the accumulation and content of subunit 7 at maturity were significantly higher than subunit 8 but similar between subunit 2 and subunit 12 in inferior grain. Moreover, the accumulation of subunit 7 and 12 in superior grain was significantly higher than in inferior grain. However, compared with the inferior grain, the GMP accumulation was higher but content was lower in superior grain at maturity.     

Neutral Lipids in Free,Bound, and Starch Lipid Extracts of Flours,Sourdough, and Portuguese Sourdough Bread Determined by NP‐HPLC‐ELSD

A detailed analysis was developed, focused on the neutral lipids (NL) in free (FL), bound (BL), and starch lipid (SL) extracts of maize and rye flours, sourdough, and broa (a traditional bread manufactured in Portugal). Selective sequential extraction of said lipids with hexane at 20°C, water‐saturated n‐butanol at 20°C, and n‐propanol‐water (3:1, v/v) at 100°C was performed to clean the lipid extracts from extraneous impurities, and isolation thereof from glyco‐ and phospholipids was by solid phase extraction of NL; these classes were then quantitatively assayed by HPLC, using evaporative light scattering detection, with calibration curves prepared with standard mixtures of NL. The BL and SL contents in the original flours increased and that of FL decreased throughout the fermentation and baking processes. The dominant NL class was not the same in all lipid extracts; the highest concentrations of triacylglycerols and the lowest concentrations of free fatty acids were detected in FL—with the former accounting for 82, 76, and 71% of the total FL in flours, sourdough, and bread, respectively. Triacylglycerols and free fatty acids also accounted for the highest concentrations found in BL: these, together with diacylglycerols, contributed up to 84% of the total neutral BL. High levels of free fatty acids and low levels of the remaining NL classes were typically found in SL: free fatty acids, triacylglycerols, sterol esters, and diacylglycerols accounted for ≈90% of the total SL.     

Creep Recovery of Wet Gluten and High‐Molecular‐Weight Glutenin Subunit Composition: Relationship with Viscoelasticity of Dough and Breadmaking Quality of Hard Red Winter Wheat

Effects of high‐molecular‐weight glutenin subunits on viscoelasticity of wet gluten, and its relationships with mixing, extensibility, and breadmaking parameters, were investigated by creep recovery using the Kelvin–Voigt model on 19 hard red winter wheat flours. Gluten samples with Glu‐A1 1 and 2* showed significant differences in retardation time (λ₂), whereas subunit 17+18 in Glu‐B1 showed higher elastic moduli (G ₀, G ₁, and G ₂) and viscosity coefficients (η₀, η₁, and η₂) compared with subunits 7+8 and 7+9. Wheats with Glu‐D1 5+10 had higher values of G ₀, G ₁, G ₂, η₀, η₁, and η₂ compared with Glu‐D1 2+12. Gluten samples were on average 5.5, 3.1, and 1.6 times less stiff than dough when comparing G ₀, G ₁, and G ₂, respectively; these differences suggest that the nongluten components have high influence in the instantaneous and first Kelvin–Voigt elements of the model, and they are manifested more quickly compared with gluten components. Higher explanation of variance of loaf volume was found in parameters η₂ and G ₂ (r = 0.57 and 0.58, respectively, P < 0.0001) compared with η₁ and G ₁ (r = 0.45 and 0.56, P < 0.01 and 0.0001, respectively). These findings indicate that large structures formed primarily by crosslinking and agglomeration of glutenins of long chain sizes (second Kelvin–Voigt element) had major effects on quality compared with short chain sizes (first element).     

Physical,Chemical, and Sensory Properties of Antioxidant‐Enriched Raw and Cooked Rice by Vacuum‐Drying Impregnation in a Semidry State

Vacuum drying was employed with a vacuum impregnation technique in a semidry state to enrich rice with antioxidants of beetroot juice. The properties of the vacuum‐dried raw and cooked rice grains were characterized. The various raw rice grains (three varieties and two storage time periods) exhibited a significant absorption of beetroot juice, which was evident from the red‐violet beetroot color of the rice, as distinguished from the white color of the control. The color increase (ΔE= 20−40) was linear with the juice content (R² = 0.96−0.99). Their total phenolic (TP) contents and 2,2‐diphenyl‐2‐picrylhydrazyl radical (DPPH) scavenging activities were enhanced (ΔTP = 21−260 mg of gallic acid equivalents/100 g of rice db and ΔDPPH = 22−64 mg of vitamin C equivalents/100 g of rice db). Their grain integrity was reduced (Δforce = −1 to −63), which was potentially associated with the formation of grain surface cracks (linear relationship of %crack and %juice with R² = 0.94−0.98). After cooking, the enriched rice grains were linearly elongated with added juice (R² = 0.88−0.97, up to 1.6‐, 2.0‐, and 2.0‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively), and the overall volume of the cooked rice was increased (likely not linear, up to 3.2‐, 4.3‐, and 4.8‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively). Such improvements in cooking qualities were obtained by this simple vacuum‐drying technique, in comparison to existing rice‐aging processes that are more time consuming. The sensorial scores of the resultant rice products were excellent. Vacuum drying is an effective tool to improve the antioxidant value of rice as well as its cooking quality, and the raw quality remains appreciable. It is a simple and rapid process that could be practical for manufacturing healthy rice products.     

Effect of Bran Extract from Pigmented Rice Superjami on the Lipid and Glucose Metabolisms in a Postmenopause‐Like Model of Ovariectomized Rats

The effect of rice bran ethanolic extract from Superjami, a new blackish‐purple pigmented cultivar, on the lipid and glucose metabolisms in a postmenopausal‐like model of ovariectomized rats was investigated. Sprague‐Dawley female rats were subjected to either bilateral ovariectomy or a sham operation and randomly divided into three dietary groups (n = 6): sham‐operated fed with normal diet (SHAM), ovariectomized fed with normal diet (OVX‐AIN76), and ovariectomized fed with normal diet supplemented with Superjami bran extract (OVX‐SJ). The OVX‐AIN76 group showed significantly higher body weight, triglyceride, total cholesterol, blood glucose, and insulin than the SHAM group. On the other hand, supplementation of Superjami bran extract markedly reduced the body weight gain and improved the lipid and glucose profiles in ovariectomized rats through inhibition of hepatic lipogenesis and adipokine production and modulation of glucose‐regulating enzyme activities. These findings demonstrate that extracts from Superjami bran may be useful in the prevention and management of postmenopause‐induced hyperlipidemia and hyperglycemia.     

Characteristics of Vegetable‐Based Twin‐Screw Extruded Yellow Perch (Perca flavescens) Diets Containing Fermented High‐Protein Soybean Meal and Graded Levels of Distillers Dried Grains with Solubles

A twin‐screw extrusion study was performed in replicated trials to produce vegetable‐based feeds for juvenile yellow perch. Two isocaloric (3.06 kcal/g) experimental diets were balanced to contain 20 and 40% distillers dried grains with solubles (DDGS) and a constant amount (20%) of fermented high‐protein soybean meal (PepSoyGen) as the fishmeal protein replacers; crude protein content was targeted at 40%. A fishmeal‐based diet was used as a control. Extrusion conditions included conditioner steam (0.11–0.16 kg/min), extruder water (0.11–0.19 kg/min), and screw speed (230–300 rpm). Increasing DDGS from 0 to 40% led to a considerable rise in bulk density, lightness L*), yellowness (b*), and unit density but to decreases in water activity (a_w) and expansion ratio by 12.6, 14.4, 23, 21, 31, and 13%, respectively. The lowest unit density of 791.6 kg/m³ and highest bulk density of 654.5 kg/m³ were achieved with diets containing 20 and 40% DDGS, respectively; changes in DDGS content did not affect extrudate moisture, absorption index, or thermal properties. Raising DDGS from 0 to 40% resulted in an increase in water solubility and redness (a*) by 13.4 and 35%, respectively. All extrudates had high durability (>98%), and low a_w of less than 0.5. Overall, this study yielded viable feeds for yellow perch.     

Impact of indigenous‐based interventions on land conservation: a case study of a soil conservation and agroforestry project,Arumeru District,Tanzania

Land degradation has been identified as a serious problem in Tanzania since the 1920s. Among the factors normally cited as contributing to land degradation are deforestation, overgrazing and inappropriate farming practices. Several attempts by the government to arrest the problem have been based on top‐down approaches. Indigenous‐based interventions are among the alternative practices adopted by the Soil Conservation and Agroforestry Project in Arumeru District, Tanzania. The main objective of this study was to assess the impact of the indigenous‐based interventions on land conservation. More specifically the study intended to assess farmers' perception of land degradation, the adoption rate of indigenous‐based interventions, the impact of those interventions, and lastly the sustainability of those interventions. Data for the study were collected through Participatory Rural Appraisal (PRA) techniques and a questionnaire survey. The Statistical Package for Social Sciences (SPSS®) was used to analyse quantitative data and Content and Structural‐Functional Analyses were used for qualitative data. The study found that the rate of land degradation was perceived by respondents to be rather severe. The study also revealed that indigenous‐based interventions, which require minimal labour and capital, have been highly adopted by many farmers while labour/capital intensive ones have been taken up by fewer farmers. In general, indigenous‐based interventions appear to have eased farm operations and contributed towards increased crop yield, improved soil fertility and increased income. Success in some of the indigenous interventions warrants their wider promotion beyond the project area. Copyright © 2005 John Wiley & Sons, Ltd.     

Impact of grass filter strips length on exported dissolved masses of metolachlor,atrazine and deethylatrazine: a four‐season study under natural rain conditions

Herbicides atrazine and metolachlor have been detected in water bodies across the world. The objective of this study was to assess the efficiency of 0‐m, 3‐m, 6‐m and 9‐m grass filter strips to reduce masses of dissolved metolachlor, atrazine and deethylatrazine (a degradation product of atrazine) exported in runoff. For that purpose, 16 uncultivated plots (3‐m wide × 65‐m long) with 0‐m‐, 3‐m‐, 6‐m‐ and 9‐m‐long grass filter strips were setup in a completely randomized block design. During four seasons, masses of dissolved atrazine, metolachlor and deethylatrazine were determined for the first four to five rain events, under natural rain conditions, after atrazine and metolachlor application. Generally, grass filter strips reduced exported herbicide masses by more than 90% and influenced atrazine and metolachlor dissipation kinetics in the field. The 3‐m grass filter strip (area ratio source/strip of 22:1) usually provided a reduction in exported herbicide masses similar to the 6‐ or 9‐m grass filter strips. Therefore, under the present experimental soil and climate conditions, a grass filter strip of 3 m would be a good compromise between environmental protection of surface waters against atrazine and metolachlor contamination and conservation of agricultural land use. Such an approach contributes to the acceptability by producers to implement optimized best management practices such as vegetated filter strips for the preservation of the quality of water resources.     

Elemental status (Cu,Mo, Co,B, S and Zn) of Scottish agricultural soils compared with a soil‐based risk assessment

Concentrations of six elements copper (Cu), molybdenum (Mo), cobalt (Co), boron (B), sulphur (S) and zinc (Zn) are summarized for Scottish advisory soil samples collected during the period 1996–2008. Accompanying cropping information indicated that the majority of samples collected for Co analysis were from grassland compared with B, S and Zn where sampling was predominantly prior to either potatoes or vegetables. The proportion of samples measured as potentially deficient [very low (VL) or low categories] were 80% for Co, compared with 50, 40, 38, 25 and 18% for Mo, S, Zn, Cu and B, respectively. Only S displayed a significant decline (ca. 2 mg S/kg) over this 13‐year period. However, comparison of Cu and Co data with some collected from an earlier time period (1973–1980) suggested little difference for Cu but a smaller number of VL and low Co status samples. A predicted risk assessment using soil parent material, texture and drainage status suggested that 22, 38 and 40% of the agricultural area of Scotland were at a high, medium and low risk of Cu deficiency; comparable numbers for Co were 48, 30 and 22%. The reliability of the risk assessment was tested using a sub‐set of advisory samples with specific information on soil series. Of the soils predicted to have a high risk of Cu deficiency, 52% actually fell into the ‘deficient’ status. A similar comparison for Co indicated 90% of the samples predicted as having a high risk of deficiency were measured as VL or low.