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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., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Durum semolina spaghetti is known to have a low-moderate glycaemic index but the impact of various processing variables during the manufacture and cooking of pasta does affect pasta structure and potentially could alter starch digestion. In this study, several process variables were investigated to see if they can impact the in vitro starch digestion in spaghetti while also monitoring the pasta's technological quality. Cooking time had a large impact on pasta starch digestion and reducing cooking from fully cooked to al dente and using pasta of very high protein content (17%), reduced starch digestion extent. The semolina particle size distribution used to prepare pasta impacted pasta quality and starch digestion to a small extent indicating a finer semolina particle size (<180 µm) may promote a more compact structure and help to reduce starch digestion. The addition of a structural enzyme, Transglutaminase in the pasta formulae improved overcooking tolerance in low protein pasta comparable to high protein pasta with no other significant effects and had no effect on starch digestion over a wide protein range (8.6–17%). While cold storage of cooked pasta was expected to increase retrograded starch, the increase in resistant starch was minor (37%) with no consequent improvement in the extent of starch digestion. Varying three extrusion parameters (die temperature, die pressure, extrusion speed) impacted pasta technological quality but not the extent of starch digestion. Results suggest the potential to subtly manipulate the starch digestion of pasta through some processing procedures. [ABSTRACT FROM AUTHOR]

Summary: Spaghetti commonly made with durum wheat, typically lacks essential amino acids and with low fibre. Legumes offer potential to improve these properties and lupin is a good choice because it is cheaper with fewer antinutritional compounds than other legumes. Spaghetti was prepared with 0%, 5%, 17% and 30% lupin protein isolate (LPI) using both single‐screw (SSEP) and twin‐screw extrusion (TSEP). LPI increased protein up to 129%, reduced cooking time, water absorption and cooked firmness while stickiness and cooking loss were increased, especially using TSEP. LPI made the dried pasta more red and yellow and decreased brightness. The percentage of starch digested under in vitro conditions was reduced using 17%LPI with TSEP and 30%LPI with SSEP compared vs. control. Microscopy revealed changes in structure by LPI which may explain impacts on technological properties and digestion. Inclusion of LPI in pasta represents a potential approach for a low‐cost improvement of nutritional value of spaghetti and potentially reducing its starch digestibility. [ABSTRACT FROM AUTHOR]

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 ( R h ) < 100 nm; 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 R h > 100 nm. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Insoluble fibres are important in human health and disease prevention and can be incorporated into food. High fibre pasta prepared with bran is typically inferior quality compared to durum pasta. This study compared spaghetti prepared from durum semolina substituted with various amounts of either durum bran or germ (pollard) dried at high temperature. Pasta was evaluated for cooking properties, texture, sensory, fibre content, antioxidant status (AO) and in vitro starch digestibility to determine the dose producing acceptable quality. Pollard at 10% substitution had minimal impact on quality with higher AO and fibre. Above 30%, pasta had undesirable colour, sensory properties and higher starch digestion. Although bran substituted pasta had undesirable sensory and technological properties, especially at 30% incorporation, it does provide more dietary fibre and antioxidants than regular pasta and does not affect starch digestibility. Interestingly, a significant amount of AO was retained in the cooked pasta. The study illustrates the value of structural analysis to explain observed technological properties of the product with fibre inclusion. [Copyright &y& Elsevier]

Grain protein content >12–13% is known to be an important factor in ensuring a good pasta quality. However, the impacts of a wide protein variation on starch digestion in the pasta are not well elucidated. In this study semolina blends were prepared to achieve a protein range of 8.9–18.8%. Dough strength was not effected but water requirements for pasta making increased as protein increased. Increasing protein content caused spaghetti cooked firmness to increase and water absorption and cooking loss to decrease linearly, these being beneficial to quality. However, spaghetti became duller with more red tones at higher protein content. As protein content increased, the extent of starch digestion decreased. Microscopy analysis suggests a more extensive and cohesive network forms at higher protein that could limit access by α-amylase and reduce starch granule gelatinization which could account for reduced digestion. [Display omitted] • As protein increases, spaghetti firmness increases, cooking loss decreases. • Spaghetti becomes duller and more reddish at higher protein. • The extent of starch digestion is reduced as protein content increases. • A more cohesive and dense protein network forms at higher protein. [ABSTRACT FROM AUTHOR]