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Changes in protein structural characteristics upon processing of gluten-free millet pasta
Get PDFProso millet exhibits favorable agronomic and nutritional properties but is currently under-utilized in the
northern hemisphere. This study compared processing-induced changes in protein characteristics of commercial
pasta to fresh gluten-free pasta from proso millet varieties differing in prolamin profile. Protein solubility, accessible thiols and secondary structures were measured in dough, sheeted and cooked pasta. Relationships between protein conformation and characteristics related to pasta quality were determined. Cooking significantly
lowered protein solubility and induced exposure of thiol groups as well as a shift in secondary structure distribution, while sheeting only had a minor effect. Random structures positively and significantly (P < 0.05)
correlated with solubility, cooking loss and protein digestibility. In contrast, β-sheets, the main secondary
structure in cooked pasta, negatively correlated with these properties. The utilization of proso millet in glutenfree pasta is promising, however, processing optimization to elicit targeted protein modifications to balance
quality and nutritional attributes requires further investigation
Physicochemical and Nutritional Characterization of Bran-Enriched Products
Get PDFThe incorporation of cereal bran or bran constituents can improve the nutritional profile of products and serve as a means to utilize milling by-products that otherwise may only go towards feed [...
Intermediate Wheatgrass (Thinopyrum intermedium) : a 360 ° evaluation
No full textIntermediate Wheatgrass (Thinopyrum intermedium), IWG, is a perennial grain currently being investigated for food uses. The benefits of perennial cultivation are manifold, including reduced nitrogen leaching and increased carbon sequestration. From a sustainability point of view, IWG seems like a perfect candidate for human food production, but for the food scientist, it does present certain challenges due to its composition. It does contain gliadins, and is thus not marketable as gluten-free, but it does not have the same profile or content of high-molecular weight glutenins and thus dough forming properties are poor compared to wheat. In addition, due to lower endosperm contents, the grain is lower in starch but higher in dietary fiber than more commonly cultivated grains. In recent years, researchers have investigated IWGs ability to form dough, its protein structures and interactions, as well as the effect of grain refinement on IWG dough rheology and bread-making performance. Starch gelatinization and retrogradation properties have also been investigated. Moreover, we are conducting storage studies evaluating rancidity due to autoxidation and enzymatic action, and phytochemical status. This presentation will provide an overview of the latest findings on IWG focusing on protein and starch features and their impact on final product quality. Improving the knowledge on IWG, its shelf life and its macromolecules will better define its application potential in human nutrition
Protein features of gluten-free pasta made from proso millet (Panicum miliaceum) and their relation to functional and nutritional characteristics
No full text1. Justification
To explore the potential of proso millet, a gluten-free cereal of low glycemic index, as ingredient in pasta, three varieties were obtained from two locations and used to produce pasta of which compositional, functional and sensory properties were previously reported. However, little is known about structural changes of proso millet protein attributes upon processing.
2. Objective
This study’s objective was assessment of pasta protein characteristics over processing.
3. Methods
Protein solubility, content of accessible thiols, and protein secondary structures were measured in dough, raw pasta after sheeting, and cooked pasta. To assess the influence of protein interaction types on solubility, three solvents were used: phosphate buffer containing 0.1 M sodium chloride, the same buffer supplemented with 4M urea, or with 4M urea and dithiothreitol. Protein secondary structures were analyzed via attenuated total reflectance Fourier transform infrared spectroscopy. Results were compared to those from commercial fresh gluten-free and wheat fettuccine.
4. Results
Solubility of proso millet proteins in pure buffer was low, only marginally enhanced by urea or dithiothreitol, and considerably declined after cooking. In dough and raw pasta, β-sheets represented the major secondary structure (55-66%) and further increased after cooking. However, while proteins in cooked millet pasta were almost exclusively aligned in β-sheets (93.9-99.9%), commercial wheat and gluten-free pasta retained some random and α-helical structures. Solubility positively correlated with cooking loss and protein digestibility, -helices positively correlated with solubility and cooking loss; random structures positively correlated with solubility, cooking loss and protein digestibility. In contrast, -sheets negatively correlated with solubility, cooking loss and digestibility.
5. Significance of your research to the food science field.
Protein attributes were shown to affect product functionality in proso millet pasta. Moreover, our data provide an explanation for the low digestibility and solubility observed for proso millet in other studies. The correlation of protein structure to quality parameters can form the basis for recipe and processing optimization
Nutritional properties of Proso millet grown as a second crop in Minnesota
No full textMillet is a drought-tolerant, nutritious gluten free grain high in resistant starch, thus well-suited for diabetics and people with celiac disease. As part of an ongoing evaluation of Proso millet as a double crop in Minnesota, our aim was to characterize six varieties (Dawn, Earlybird, Horizon, Snowbird, Sunrise, Sunup) of decorticated Proso millet grown in two locations in 2015 and compare them to a commercial Proso millet. Proximate analysis was conducted using standard methods, and pasting profiles measured with a micro viscoamylograph. Total and digestible starch was determined enzymatically. Color was measured on a chromameter, in addition to carotenoid quantification via HPLC. Growing location influenced moisture and lipid contents more than variety did, and both parameters were positively correlated. Dietary fiber contents tended to be influenced by variety but not growing location. Sample color most notably differed in lightness and yellowness, due to differences in carotenoid (lutein and zeaxanthin) content. Proso millet grown in Minnesota had lower pasting temperature, similar peak viscosity, higher breakdown and lower setback values than the commercial millet. Earlybird had lower pasting temperature, lower final viscosity and setback than all other millets, regardless of growing location. This variety had similar starch, protein and fat contents than other samples; however, it contained more soluble dietary fiber. In vitro starch digestibility of cooked samples was affected by growing location and variety, with Horizon having the least rapidly digestible starch and Dawn and Snowbird having the most slowly digestible starch. Our characterization of Proso millets will lead to the selection of specific varieties for breeding purposes that are best suited for the production of specific cereal-based goods such as wafers, cookies or bread
Promoting proso millet (Panicum miliaceum) for food use: Chemical characterisation and performance as ingredient in gluten-free pasta
No full textDespite of favourable nutritional and agronomic properties, millet is currently underutilized in North America and Europe. Our aim was to demonstrate millet’s suitability as ingredient in gluten-free foods, with the ultimate goal that such an effort could promote millet cultivation by establishing a market for its products.
In the project’s first phase, six proso millet (Panicum milliaceum) varieties grown as a double crop in two locations in the American Midwest were screened for chemical and nutritional parameters. In the second phase, four of the samples were selected as raw materials for glutenfree pasta, based on harvest yields, prolamin profile, and amylose content. The pasta was evaluated for nutritional aspects (starch and protein digestibility), quality markers (cooking loss, optimum cooking time, water absorption, firmness, yellowness and carotenoid content) and subjected to descriptive analysis by a trained sensory panel. To gain more insight into the role of prolamins on pasta attributes, we evaluated protein solubility and structural characteristics (accessible thiol groups and secondary structure) across processing stages, i.e. compared dough, raw pasta after sheeting, and cooked pasta. All analyses were also performed on two commercial controls, one wheat-based, one gluten-free. The millet samples were similar in protein, fat, fibre, starch, and ash content, and displayed similar protein and starch digestibility. However, varieties differed in amylose content, affecting pasting properties. Both amylose content and prolamin profile affected millet pasta properties, including cooking loss and instrumental firmness, as well as texture ratings by the sensory panel. Proso-millet based pasta displayed several superior characteristics to commercial glutenfree pasta, specifically, lower cooking loss, higher carotenoid levels, and less rapidly digestible starch.
Results show that proso millet is a feasible ingredient for food product development, especially for the gluten-free market. The study also highlights characteristics that require improvements, and parameters that potentially distinguish millet from other grains
Sensory evaluation of gluten-free fresh pasta from proso millet
No full textDespite being gluten-free and exhibiting favorable agronomic properties, millet is underutilized in North America and Europe. To promote its use in food products, we previously reported on the suitability of proso millet for preparation of gluten-free pasta, focusing on cooking quality, compositional and nutritional aspects. The aim of this study was to gain insight into consumer evaluation of pasta, and relate compositional attributes to sensory perception.
Fettuccine-type fresh pasta was prepared from four millet varieties with different amylose content (from 7.8% to 35.7%) and prolamin profile. Samples were compared to two commercial fettuccine products, one wheat-based, and the other gluten-free. Freshly cooked samples were evaluated by a sensory panel trained on descriptive analysis . Data were analyzed via ANOVA, Student-Neuman-Keuls tests, and principal component analysis that included instrumental data as supplementary variables.
Several attributes related to appearance, taste and texture differed significantly among samples. One millet pasta (from variety Earlybird) was ranked as more yellow than the commercial gluten-free pasta, but not different in yellowness to wheat; all other millet varieties resulted in pasta that was rated more yellow than commercial gluten-free, but less yellow than wheat pasta. This assessment is in agreement with instrumental analysis of carotenoids via HPLC and color via chromameter. All millet samples were perceived as more uniform, but also more gray than commercial samples. Regarding taste, Earlybird millet pasta received higher bitterness and bitterness aftertaste scores than other millet and commercial samples. In terms of texture, millet pasta was significantly starchier, less elastic and grainier than both commercial samples. The presence of high molecular weight prolamins corresponded to lower perceived stickiness, but higher graininess. Higher amylose contents increased firmness and chewiness, but reduced stickiness. Earlybird millet pasta was significantly stickier, but less chewy and firm than all other samples, in agreement with low instrumental firmness. Principle component analysis differentiated commercial samples from millet pasta, as well as Earlybird pasta from other millet samples. Earlybird and wheat pasta were characterized by high yellowness, low firmness and low chewiness; the other millet samples were of intermediate yellowness and firmness, and commercial GF pasta exhibited high firmness and low yellowness. Graininess, starchiness, and uniformity were characteristic for all millet pasta; high tensile strength and elasticity were characteristic for both commercial controls. Our study reveals which attributes distinguished millet from commercial pasta, and highlights parameters that warrant improvement by recipe or processing optimization.
Learning objectives
• Key attributes that distinguish fettuccine-type millet pasta from commercial gluten-free and wheat pasta
• Influence of amylose and prolamin profile on sensory outcomes
• Relation of instrumental to sensorial characterization of fresh past
Suitability of different proso millet varieties for production of gluten-free fresh pasta
No full textDespite the environmental and nutritional benefits of millet, very few food products are prepared from this grain, especially outside its countries of origin. The limited information on the characteristics of the various species accounts for scarce millet human consumption. In this frame, the aim of the study was to evaluate the pasta making performance of decorticated Proso millet.
Among six millet varieties grown in two locations (Lamberton and Waseca, MN), four samples were selected based on amylose content (AC) and presence of high molecular weight prolamins (HMWp): Horizon Lamberton (25.09% AC; HMWp), Sunrise Lamberton (31.68% AC; HMWp), Earlybird Lamberton (7.88% AC; no HMWp) and Sunrise Waseca (34.77% AC; no HMWp). Fresh pasta formulation included: millet flour (65g/100g db), potato starch (23g/100g db), whole liquid eggs (10g/100g db), guar gum (1.5g/100g db), salt (0.5 g/100g db) and water (23-26g/100g dough, as needed to obtain sheetable dough). Commercial gluten-free (GF) and wheat (W) fresh pasta were used as controls. Pasta color and carotenoids content were assessed before and after cooking, using a chromameter and HPLC, respectively. Cooking loss and firmness were measured following AACC method 66-50.01; and in-vitro starch digestibility was evaluated by an enzymatic approach.
Millet pasta yellowness (b*) and carotenoids content were higher than GF. Earlybird Lamberton pasta had the highest b* values and carotenoids content before and after cooking. With regard to pasta quality, cooking loss of millet pasta (1.64 – 2.36 %) was lower than that of GF and W (4.82% and 3.48%, respectively). Interestingly, Sunrise Waseca (high AC; no HMWp) yielded pasta with the lowest cooking loss value. Firmness was lower for millet (3.64 and 5.18 N for Earlybird and Horizon Lamberton, respectively) than GF (10.31 N), whereas W showed an intermediate value (5.95 N). Earlybird Lamberton - with the lowest AC - resulted in the softest sample; whereas, prolamins had a minor effect on pasta firmness. Concerning in-vitro starch digestibility, all millet pasta showed significant lower levels of rapidly digestible starch (RDS) than GF, yet had very similar levels to that of W, suggesting low glycemic impact.
In conclusion, Proso millet is suitable for the production of fresh pasta with better quality than that of a commercial GF product. The effect of prolamins on pasta cooking behavior should be further investigated. These results will support the breeding program for the selection of the Proso millet varieties more suitable for fresh gluten free pasta production
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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