Mike Sissons

Effect of Starch Granule Size Distribution and Elevated Amylose Content on Durum Dough Rheology and Spaghetti Cooking Quality

ABSTRACT To obtain an indication of the effect of increasing the starch amylose content above normal levels (27–74%) and increasing the percentage of B-type starch granules (11–60%) on durum dough properties and the quality of the spaghetti derived from these doughs, the reconstitution approach was used. Reconstituted flours were prepared from a common Wollaroi gluten, solubles and tailings fraction combined with starches containing varying B-granule contents, or with starches from maize with varying amylose content. An increased B-granule content increased farinograph water absorption. Cooked spaghetti firmness was highest with B-type granules at 32–44% (volume percentage basis), which is ≈10–15% higher than normally found in durum starch. Increasing the amylose content in the starch caused the dough to be more extensible, increased spaghetti firmness, and decreased water absorption with optimum quality of amylose at 32–44%. The information indicates there would be benefit in producing durum wheats with ...

Application of the Single-Kernel Characterization System to Durum Wheat Testing and Quality Prediction

ABSTRACT The Single Kernel Characterization System (SKCS 4100) measures single kernel weight, width, moisture content, and hardness in wheat grain with greater speed than existing methods and can be calibrated to predict flour starch damage and milling yield. The SKCS 4100 is potentially useful for testing applications in a durum improvement program. The mean SKCS 4100 kernel weight and moisture values from the analysis of 300 individual kernels gave good correlations with 1,000 kernel weight (r2 = 0.956) and oven moisture (r2 = 0.987), respectively. Although significant correlations were obtained between semolina mill yield and SKCS 4100 weight, diameter, and peak force, they were all very low and would be of little use for prediction purposes. Similarly, although there were significant correlations between some SKCS 4100 parameters and test weight and farinograph parameters, they too were small. The SKCS 4100 has been calibrated using either the single kernel hardness index or crush force profile to obj...

Optimisation of resistant starch II and III levels in durum wheat pasta to reduce in vitro digestibility while maintaining processing and sensory characteristics.

Foods with elevated levels of resistant starch (RS) may have beneficial effects on human health. Pasta was enriched with commercial resistant starches (RSII, Hi Maize™ 1043; RSIII, Novelose 330™) at 10%, 20% and 50% substitution of semolina for RSII and 10% and 20% for RSIII and compared with pasta made from 100% durum wheat semolina to investigate technological, sensory, in vitro starch digestibility and structural properties. The resultant RS content of pasta increased from 1.9% to ∼21% and was not reduced on cooking. Significantly, the results indicate that 10% and 20% RSII and RSIII substitution of semolina had no significant effects on pasta cooking loss, texture and sensory properties, with only a minimal reduction in pasta yellowness. Both RS types lowered the extent of in vitro starch hydrolysis compared to that of control pasta. X-ray diffraction and small-angle scattering verified the incorporation of RS and, compared to the control sample, identified enhanced crystallinity and a changed molecular arrangement following digestion. These results can be contrasted with the negative impact on pasta resulting from substitution with equivalent amounts of more traditional dietary fibre such as bran. The study suggests that these RS-containing formulations may be ideal sources for the preparation of pasta with reduced starch digestibility.

Combined techniques for characterising pasta structure reveals how the gluten network slows enzymic digestion rate

The aim of the present study is to characterise the influence of gluten structure on the kinetics of starch hydrolysis in pasta. Spaghetti and powdered pasta were prepared from three different cultivars of durum semolina, and starch was also purified from each cultivar. Digestion kinetic parameters were obtained through logarithm-of-slope analysis, allowing identification of sequential digestion steps. Purified starch and semolina were digested following a single first-order rate constant, while pasta and powdered pasta followed two sequential first-order rate constants. Rate coefficients were altered by pepsin hydrolysis. Confocal microscopy revealed that, following cooking, starch granules were completely swollen for starch, semolina and pasta powder samples. In pasta, they were completely swollen in the external regions, partially swollen in the intermediate region and almost intact in the pasta strand centre. Gluten entrapment accounts for sequential kinetic steps in starch digestion of pasta; the compact microstructure of pasta also reduces digestion rates.

Quality of Fiber-Enriched Spaghetti Containing Microbial Transglutaminase

ABSTRACT The effects of transglutaminase (TG) on the properties of semolina dough and pasta cooking properties in durum-only and fiber-enriched pasta were investigated. TG was blended at levels 0, 0.05, 0.1, 0.25, 0.5, and 1% of semolina weight with semolina and semolina-pollard (60% w/w) and semolina-guar gum (15%) mixtures. The addition of TG increased dough maximal resistance, making the dough inextensible at >1%. Optimum effects on dough strength were obtained at 0.5% TG; this dough gave the firmest and least sticky pasta. A more extensive and thicker protein matrix was observed in the TG pasta by confocal scanning laser microscopy, indicating more cross-links were formed, a finding supported by measuring percentage of unextracted polymeric protein. TG was unable to overcome the negative effect of 60% pollard on cooking loss or 15% guar gum on stickiness. Gluten was generally more effective than TG in restoring the properties of pastas with added fiber.

Evaluation of the technological and sensory properties of durum wheat spaghetti enriched with different dietary fibres

The incorporation of fibres, whether insoluble or soluble, in durum wheat pasta negatively impacts desirable end-use properties, especially if incorporated in significant amounts. Fibres can disrupt the starch-protein matrix of the dough during pasta preparation and can also often swell more readily with water than starch, competing with the starch for water during dough development. Similar degrees of substitution with different fibres gave markedly different impacts on firmness, stickiness, cooking loss and sensory attributes, suggesting that results obtained for one fibre cannot readily be generalized to other fibres. The in vitro starch digestibility of the pastas was significantly reduced when resistant starch, β-glucan-enriched flour, carboxymethyl cellulose or guar gum was incorporated but increased when pollard or inulin was added. In many instances, different sources of the same fibre gave dramatically different impacts on the properties of cooked durum wheat pasta.

Effect of β-Glucan on Technological, Sensory, and Structural Properties of Durum Wheat Pasta

ABSTRACT β-Glucan is known to have valuable properties for preventative health and is finding widespread use in foods. This study investigated the benefit of adding a commercial source of β-glucan, Barley Balance (BB) flour, as a functional ingredient in spaghetti. Durum wheat semolina was substituted with BB at levels of 7.5, 15, and 20%, from which spaghetti was prepared on a laboratory scale. The substitution of BB increased the β-glucan content of semolina from 0.3 to 6% in uncooked and 8% in cooked pasta. Antioxidant activity (measured by 2,2-diphenyl-1-picrylhydrazyl) increased with BB and did not decline significantly on processing and cooking. Compared with the control, 7.5% BB had no or minimal effect on pasta cooking loss, stickiness, water absorption, aroma, and sensory texture. However, at higher doses, pasta became less yellow and more brown, firmer, of inferior aroma, more rubbery, and chewy, but less floury to the mouth. The extent of starch digestion decreased with increasing quantities of...

Durum wheat quality in high-input irrigation systems in south-eastern Australia

Abstract. To extend the production base of durum wheat in Australia, field trials were conducted on seven registered durum varieties across four seasons and six sites in locations where irrigation was supplied during crop growth. The purpose was to determine if the quality of the grain produced met the requirements for good milling and pasta-making quality and to understand the genotype, environment and their interaction in affecting yield and technological quality of the grain and derived pasta. High grain yields and grain protein were obtained, producing large grain weights, low screenings and low percentage of hard vitreous kernels. Yellow colour of semolina and pasta was reduced marginally but dough and other pasta technological characteristics were similar to typical dryland durum production, with some exceptions. Varieties were identified with potential for production under irrigation.

Compact structure and proteins of pasta retard in vitro digestive evolution of branched starch molecular structure.

The roles that the compact structure and proteins in pasta play in retarding evolution of starch molecular structure during in vitro digestion are explored, using four types of cooked samples: whole pasta, pasta powder, semolina (with proteins) and extracted starch without proteins. These were subjected to in vitro digestion with porcine α-amylase, collecting samples at different times and characterizing the weight distribution of branched starch molecules using size-exclusion chromatography. Measurement of α-amylase activity showed that a protein (or proteins) from semolina or pasta powder interacted with α-amylase, causing reduced enzymatic activity and retarding digestion of branched starch molecules with hydrodynamic radius (Rh)<100nm; this protein(s) was susceptible to proteolysis. Thus the compact structure of pasta protects the starch and proteins in the interior of the whole pasta, reducing the enzymatic degradation of starch molecules, especially for molecules with Rh>100nm.

GlutoPeak: A Breeding Tool for Screening Dough Properties of Durum Wheat Semolina

A rapid shear-based test using a GlutoPeak instrument was compared with tests commonly used by durum wheat breeders to assess the potential of this instrument to discriminate between samples. Thirty-two durum wheat semolina samples were analyzed by mixograph, SDS sedimentation (SDSS), gluten index (GI), and GlutoPeak testing. A subset was also tested for pasta quality. GlutoPeak peak maximum time (PMT) was the best indicator of gluten strength and correlated well with the other tests except SDSS. Samples with higher levels of SDS-unextractable glutenin (insoluble protein [IP]) had stronger dough and longer PMT, but the GlutoPeak test only correlated with pasta stickiness using a smaller set of samples. The range in mixogram profiles encountered in breeding material was related to the IP content, and the pasta made from the different types was of similar quality, differing more because of protein content rather than mixogram type. The GlutoPeak test is faster than GI and uses less sample, requires little t...