Traditional and Non-Conventional Pasta-Making Processes: Effect on In Vitro Starch Digestibility.

Pasta is a carbohydrate-rich food with a low glycemic index (GI) and is one of the main sources of slowly digestible starch (SDS). The presence of bran fractions (BFs) in pasta may enhance its health potential, owing to the content of fiber, micronutrients, and bioactive compounds; however, at the same time, BF may affect starch digestibility. In this study, the bioaccessibility of starch in pasta made with BF-enriched semolina (BF pasta), or only with micronized debranned kernel (DK pasta), and a control pasta made with traditional semolina was evaluated by applying two different in vitro models. The control pasta showed a percentage of SDS about four-fold higher than that of the BF pasta and 1.5-fold higher than that of the DK pasta (p < 0.05). The amount of starch released during simulated gastrointestinal digestion was slightly lower, but not significantly different, for the control pasta than for both the BF and DK pasta. These results suggest that the presence of a higher amount of dietary fiber in BF pasta can affect the structure of the food matrix, interfering with the formation of the gluten network, water absorption, and starch granule accessibility, while micronization could enhance starch digestibility due to starch gelatinization. These findings emphasize the need to optimize the process for producing fiber-rich pasta without affecting its low starch digestibility and, consequently, its GI.

From seed to cooked pasta: influence of traditional and non-conventional transformation processes on total antioxidant capacity and phenolic acid content.

The aim of this work was to compare the traditional with a non-conventional (i.e. kernel micronisation) durum wheat milling process by monitoring the content of bound, conjugated and free phenolic acids (PAs) and the level of the total antioxidant capacity (TAC) occurring in the durum wheat pasta production chain, from seed to cooked pasta. The traditional transformation processes negatively influenced TAC and PA content (40% and 89% decrease from seed to cooked pasta, respectively), mainly during the milling process (25% and 84% decrease of TAC and PA, respectively), which has been related to the removal of external layers of kernels. Conversely, the micronisation applied on durum wheat kernels allowed to obtain whole-wheat pasta that preserved the seed endowment of antioxidant compounds even in cooked pasta. These results indicate the micronisation as a valuable approach to produce pasta with improved nutritional value and potential health-promoting effects compared to the traditional pasta.

Use of bran fractions and debranned kernels for the development of pasta with high nutritional and healthy potential.

The quality of pasta produced with debranning products (bran fractions, BF, and debranned kernels, DK) of durum wheat was investigated by evaluating their total antioxidant capacity, occurrence of nutritional and bioactive compounds, and sensory properties. Two pasta samples, produced with BF-enriched semolina (BF pasta) or only with micronized DK (DK pasta), respectively, were compared with pasta made with traditional semolina (control pasta). BF pasta and DK pasta displayed significantly higher content of bioactive compounds, such as phenolic compounds and dietary fibre, than control pasta, to a different extent for the diverse compounds. The present study indicates that the debranning process allows to produce pasta with a high content of healthy compounds and minimal effects on sensory properties, using only the natural endowment of durum wheat. This approach is suitable to produce cereal-based foods with the potential nutritional and health benefits of partially refined cereals and limitation of their main drawbacks.

The impact of the SSIIa null mutations on grain traits and composition in durum wheat.

Starch represents a major nutrient in the human diet providing essentially a source of energy. More recently the modification of its composition has been associated with new functionalities both at the nutritional and technological level. Targeting the major starch biosynthetic enzymes has been shown to be a valuable strategy to manipulate the amylose-amylopectin ratio in reserve starch. In the present work a breeding strategy aiming to produce a set of SSIIa (starch synthases IIa) null durum wheat is described. We have characterized major traits such as seed weight, total starch, amylose, protein and ß-glucan content in a set of mutant families derived from the introgression of the SSIIa null trait into Svevo, an elite Italian durum wheat cultivar. A large degree of variability was detected and used to select wheat lines with either improved quality traits or agronomic performances. Semolina of a set of two SSIIa null lines showed new rheological behavior and an increased content of all major dietary fiber components, namely arabinoxylans, ß-glucans and resistant starch. Furthermore the investigation of gene expression highlighted important differences in some genes involved in starch and ß-glucans biosynthesis.

Fructan biosynthesis and degradation as part of plant metabolism controlling sugar fluxes during durum wheat kernel maturation.

Wheat kernels contain fructans, fructose based oligosaccharides with prebiotic properties, in levels between 2 and 35 weight % depending on the developmental stage of the kernel. To improve knowledge on the metabolic pathways leading to fructan storage and degradation, carbohydrate fluxes occurring during durum wheat kernel development were analyzed. Kernels were collected at various developmental stages and quali-quantitative analysis of carbohydrates (mono- and di-saccharides, fructans, starch) was performed, alongside analysis of the activities and gene expression of the enzymes involved in their biosynthesis and hydrolysis. High resolution HPAEC-PAD of fructan contained in durum wheat kernels revealed that fructan content is higher at the beginning of kernel development, when fructans with higher DP, such as bifurcose and 1,1-nystose, were mainly found. The changes in fructan pool observed during kernel maturation might be part of the signaling pathways influencing carbohydrate metabolism and storage in wheat kernels during development. During the first developmental stages fructan accumulation may contribute to make kernels more effective Suc sinks and to participate in osmotic regulation while the observed decrease in their content may mark the transition to later developmental stages, transition that is also orchestrated by changes in redox balance.

Qualitative and quantitative determination of peptides related to celiac disease in mixtures derived from different methods of simulated gastrointestinal digestion of wheat products.

During wheat digestion, gluten-derived proteolytic resistant peptides are generated, some of them involved in celiac disease. In vitro digestion models able to mimic the peptides generated in the human gastrointestinal tract are extremely useful to assess the pathogenicity of wheat-derived products. In this paper, samples belonging to three different durum wheat varieties were taken at six different steps of the pasta production chain and two different digestion models present in the literature were assessed on the different samples: a more complex one using artificial fluids simulating the exact composition of digestive juices, and a simplified method based on a peptic-tryptic/chymotryptic treatment of wheat ethanolic extract. An extensive characterization of the peptides generated using two in vitro digestion models was performed through LC-MS/MS techniques and the two methods were compared in order to evaluate qualitative and quantitative differences and their possible implications for varietal screening. Strong differences in the type of peptides produced with the two methods were detected, indicating that the simplified method can still be used for a varietal screening but is not representative of the peptides really generated after physiological human digestion. Results indicate a clear necessity of physiologically accurate models for simulating human gastrointestinal digestion of wheat products.

Identification and quantification of soluble free, soluble conjugated, and insoluble bound phenolic acids in durum wheat (Triticum turgidum L. var. durum) and derived products by RP-HPLC on a semimicro separation scale.

A straightforward semimicro separation scale RP-HPLC method was developed for the identification and quantification of phenolic acids (PAs) occurring as soluble free, soluble conjugated, and insoluble bound compounds, which were independently extracted from wholemeal of durum wheat and from its derived products coarse bran, semolina, and dried pasta. A narrow bore column and a semimicro photodiode array detector (PDA) cell, in conjunction with a single quadrupole mass spectrometer, equipped with an electrospray ionization source (ESI-MS), were employed. The method was validated in terms of linearity of calibration graphs, limits of detection, limits of quantification, repeatability, and accuracy, which was evaluated by a recovery study. In each sample (wholemeal, coarse bran, semolina, and dried pasta), the total amounts of the three different forms of PAs were in the order bound > conjugated > free, with bound PAs accounting for 61.0-83.6% of the total PAs. Ferulic acid was the most abundant PA in both soluble free and insoluble bound forms, whereas sinapic acid predominated in the conjugated ones. The highest PA content, calculated as the sum of total PAs quantified in the three forms, was found in coarse bran, followed by wholemeal, semolina, and dried pasta.

Quality and nutritional properties of pasta products enriched with immature wheat grain.

In this study, nutritional and sensory properties of pasta enriched with 30% immature wheat grain (IWG), a natural source of fructo-oligosaccharides (FOS), are evaluated. Colour and cooking quality, nutritional value and glycaemic index (GI) of pasta were assessed in comparison with commercially enriched inulin and 100% wholewheat pastas. IWG integration induced deep changes in colour, without negatively affecting the cooking quality of pasta, and promoted nutritional quality by increasing the fibre content; IWG pasta presented a remarkable leaching of FOS in cooking water, thus providing only 1 g of FOS per serving. IWG pastas showed a GI of 67 (dried) and 79 (fresh), not significantly different from commercial pasta products. IWG can be considered an interesting ingredient to obtain functional products 'naturally enriched' in FOS and fibre. Results about FOS leaching suggest that, in dealing with functional effects, the actual prebiotic content should be carefully considered on food 'as eaten'.

Structure-quality relationship in commercial pasta: a molecular glimpse.

Presence and stability of a protein network was evaluated by fluorescence spectroscopy, by protein solubility studies, and by assessing the accessibility of protein thiols in samples of commercial Italian semolina pasta made in industrial plants using different processes. The pasting properties of starch in each sample were evaluated by means of a viscoamylograph. Magnetic resonance imaging (MRI) was used to evaluate water distribution and water mobility in dry pasta, and at various cooking times. The molecular information derived from these studies was related to sensory indices, indicating that protein reticulation was dependent on the process conditions, which affected water penetration, distribution, and mobility during cooking. Products with a crosswise gradient of water mobility once cooked had the best sensory scores at optimal cooking time, whereas products with a less compact protein network performed better when slightly overcooked.

Durum wheat in conventional and organic farming: yield amount and pasta quality in Southern Italy.

Five durum wheat cultivars were grown in a Mediterranean area (Southern Italy) under conventional and organic farming with the aim to evaluate agronomic, technological, sensory, and sanitary quality of grains and pasta. The cultivar Matt produced the best pasta quality under conventional cropping system, while the quality parameters evaluated were unsatisfactory under organic farming. The cultivar Saragolla showed the best yield amount and pasta quality in all the experimental conditions, thus proving to be the cultivar more adapt to organic farming. In all the tested experimental conditions, nivalenol (NIV) and deoxynivalenol (DON) occurrence was very low and the other mycotoxins evaluated were completely absent. These data confirm the low risk of mycotoxin contamination in the Mediterranean climate conditions. Finally, it has been possible to produce high-quality pasta in Southern Italy from durum wheat grown both in conventional and organic farming.

Properties of the protein and carbohydrate fractions in immature wheat kernels.

The time course of compositional changes in the polysaccharide and protein fractions, and of changes in protein structural properties, was investigated in grains of two Italian durum wheat cultivars, Ofanto and Duilio, and the pattern of changes was found to be specific to each cultivar. The fructo-oligosaccharide content in ripening kernels was different between cultivars, as was the pattern of starch accumulation. Evaluation of gluten proteins by Western-blotting using broad-specificity anti-gliadin antibodies showed the sudden appearance of immunoreactive proteins during ripening. Protein surface hydrophobicity and thiol content and accessibility were evaluated in conditions apt at assessing changes in protein interaction and/or in aggregative patterns. Proteins in the two cultivars showed differences in their surface hydrophobicity and in their content of accessible thiols. The simultaneous evaluation of changes in the individual components indicates that use of immature grains for the production of functional foods will require accurate monitoring of the rapidly evolving biopolymer patterns, and careful choice of the cultivar.