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.     

Identification of durum wheat cultivars and monovarietal semolinas by analysis of DNA microsatellites

 Microsatellites isolated in bread wheat were used to identify 20 Italian durum wheat (Triticum turgidum var. durum L.) cultivars. A total of 15 microsatellite primer pairs were tested against DNA extracted from leaf tissue, single seeds and semolina. Twelve markers showed allelic polymorphism among the 20 cultivars, providing a total of 41 different alleles. Firstly, an analysis of microsatellite informativeness in the chosen set of durum wheat cultivars was made and a set of highly polymorphic microsatellites was established. Secondly, among the most polymorphic cultivars, the minimum number of microsatellites able to distinguish all cultivars was determined. A set of five microsatellites was found sufficient to differentiate the durum wheat cultivars examined. The method is directly applicable to seeds and semolina, and is suitable for detecting seed mixtures in the same seed lot. Received: 22 February 1999 / Revised version: 19 April 1999     

Effect of inulin soluble dietary fibre addition on technological, sensory, and structural properties of durum wheat spaghetti

Investigation of two inulins with differing degrees of polymerisation and crystallinity demonstrated different levels of integration with the starch-gluten matrix during pasta preparation. The impact of higher molecular weight inulin incorporation on technological and sensory properties was minimal, with deterioration in properties becoming significant only at 20% incorporation, while lower molecular weight had a greater negative impact on pasta firmness, cooking loss, and sensory acceptability. In vitro starch digestion of pasta was reduced with up to 5% addition of inulin of degree of polymerisation 12-14 (FH-D), but increased with high levels of addition. These effects were not observed in inulin with a degree of polymerisation of 7-8 (LV-100). Microscopy showed the starch granules were apparently encapsulated by a protective coat of inulin FH-D, but at 20% a disruption to the matrix was evident. For inulin FH-D, XRD analysis of digested pasta found a maximum crystallinity which coincided with the maximum reduction in starch hydrolysis, suggesting that a stronger gluten matrix enhanced by added inulin is indeed structurally different at the nanometre level.     

Carotenoids evolution during pasta,bread and water biscuit preparation from wheat flours

The loss of carotenoids content during food processing was investigated during the production of bread, water biscuits and pasta from refined flours of einkorn, bread and, for pasta only, durum wheat semolina.     

Prediction of pasta drying process based on a thermogravimetric analysis

The drying process of durum wheat semolina dough was measured by thermogravimetry in the temperature and relative humidity ranges of 30–90 °C and 0–80%, respectively, in order to predict the drying process of pasta under any drying conditions. About 20% of the water was evaporated during the constant drying-rate period which has been ignored in previous studies. It is demonstrated that the constant drying-rate period should be taken into account in order to predict the drying curve with a high accuracy. The drying rate during the constant drying-rate period and the mass transfer coefficient estimated by the thermogravimetric analysis were expressed as functions of the temperature and relative humidity, and they were useful for predicting the drying processes of pasta under any drying conditions including the programmed ones.     

Effect of soluble fibre (guar gum and carboxymethylcellulose) addition on technological, sensory and structural properties of durum wheat spaghetti

Incorporation in pasta of either of two soluble fibres, carboxymethylcellulose sodium salt (CMC) and guar gum (GG), was found to significantly reduce the rate of invitro starch digestion. The amount of reducing sugars produced over 300 min was reduced by 18% at 1.5% CMC incorporation and 24% at 20% GG incorporation. Negative effects on sensory and technological properties were seen at the high levels of GG needed to reduce the rate of in vitro digestion, and a ‘matty’ layer covering the surfaces of starch granules was observed by scanning electron microscopy and confocal scanning laser microscopy. By contrast, levels of CMC incorporation giving large reductions in in vitro digestion had no negative effects on pasta properties. No significant alteration in pasta structure on CMC incorporation was observed by microscopy. The large difference in the amounts of soluble fibre required to bring about equivalent reductions in digestion rate suggests that different mechanisms may be involved in the two cases.     

Can variation in durum wheat pasta protein and starch composition affect in vitro starch hydrolysis?

Pasta was prepared with modifications designed to alter its rate of digestion, including altering the ratio of A- to B-granules, incorporating higher amylose content, and varying the glutenin:gliadin ratio and HMW:LMW glutenin subunit ratio. The effects of these modifications were investigated using an in vitro hydrolysis method. A significant reduction in parameters related to glycaemic index was established for high amylose pastas and pastas with 40% B-granule composition, while most other modifications increased the rate of starch hydrolysis. All effects observed were small in comparison to the effect on glycaemic index previously obtained by addition of soluble fibres.     

A polyphasic approach in order to identify dominant lactic acid bacteria during pasta manufacturing

Using a polyphasic approach, we have isolated and identified, lactic acid bacteria (LAB) in samples directly collected from an artisanal pasta-making manufactory located in Puglia (South Italy). Samples were collected during several steps of pasta processing and LAB were isolated on MRS and M17 plates. Furthermore, strains were grouped in a total of eight species by means of randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) typing and 16S rDNA sequencing. The majority of strains were identified as belonging to Pediococcus pentosaceus and Enterococcus faecium species. The remaining strains were characterized and assigned to Weissella confusa, Pediococcus acidilactici, Leuconostoc mesenteroides, Leuconostoc citreum, Lactobacillus fermentum and Lactobacillus plantarum species. Strains were identified from all the analysed samples, and growth of LAB was monitored from extrusion to pre-heating steps.     

The role of a low molecular weight glutenin fraction in the cooking quality of durum wheat pasta

Durum wheat glutenin fractions, composed of two low molecular weight proteins DSG-1 and DSG-2 (durum wheat (Triticum durum Desf) sulphurrich glutenin fractions) were extracted from semolina samples using a low concentration of Na tetradecanoate after extracting albumins, globulins and gliadins. DSG proteins have a high? SH plus S? S content. A highly significant correlation was found between the ? SH plus S? S content of this DSG-rich fraction and the cooking quality of pasta (0.63, P <0.01 with firmness and 0.86, P <0.001 with the state of the surface of the cooked pasta) and this seems to be a functional relationship. The use of acetic acid at various molarities showed the presence of high molecular weight glutenin fractions with differing solubility properties. In this respect, differences were found between varieties which are placed in the same group according to the classification of durum wheats based upon the composition of high molecular weight glutenin subunits.     

Sensory and nutritional attributes of fibre-enriched pasta

The objective of this study was to evaluate the impact that the incorporation of resistant starch type II (RSII), resistant starch type IV (RSIV) and oat bran (OB) have on sensory and nutritional quality of pasta. RSII, RSIV and OB were incorporated into recipes in four proportions (w/w): 2.5, 5.0, 7.5, and 10.0 g/100 g. Resistant, digestible and total starch were measured in cooked pasta. An in vitro digestion and sensory analysis of pasta were performed in order to estimate glycemic index. Results showed that both, the type and amount of added fibre influence nutritional quality of pasta. Incorporation of RSII into pasta formulation generates an additional quantity of resistant starch content in cooked pasta. Differences in in vitro digestibility of pasta can be appreciated. RSIV presented the greatest effect on total starch hydrolysis. The lower glycemic index was obtained with addition of RSIV and RSII at 7.5 g/100 g and 10.0 g/100 g. Sensory analysis showed high scores for overall acceptability for Control, RSII and RSIV samples. Results suggest that by using insoluble fibre it is possible to enhance the nutritional quality of pasta, without affecting its sensory properties negatively.     

Sensitivity analysis of parameters affecting the drying behaviour of durum wheat pasta

In this work, a comprehensive model of pasta drying combining Neumann boundary conditions, differential shrinkage and with consideration of the constant drying rate period and falling drying rate period was investigated through sensitivity and uncertainty analysis. Results confirmed that shrinkage, moisture loss and drying rate during the constant drying rate period and external resistance to mass transfer did not have a significant impact on the predicted required drying time. The predicted required drying time was influenced predominantly by the effective moisture diffusion coefficient. A correlation to estimate the effective moisture diffusion coefficient was developed from published values and was used to predict the required drying time with an uncertainty of ±3.5 h at a 90% confidence interval. Since this magnitude of uncertainty is unreasonable for most industrial uses, accurate data collection of effective moisture diffusivity should be viewed as a major objective in pasta drying research.     

Effect of transglutaminase on the quality of wheat-based pasta products

Transglutaminase (TG) enzyme was tested in T. aestivum and T. durum wheat-based model systems to evaluate the quality improvement to pasta imparted by cross-linking. Quality was measured by the enhancement in sensory and cooking properties. In this process, tests were also performed to establish the biochemical structure-functions of the proteins involved at TG enzyme concentrations between 10 and 200 mg kg⁻¹. It was observed that the amounts of water/salt-, the alcohol- and the alkali-soluble protein fractions were reduced significantly. Change in the molecular weight distribution assessed by SDS PAGE was also noticed. The sensory properties were observed to improve from high water uptake and low cooking loss. The TG treatment changed the gluten structure in the modified pasta products. Immune-reactive gliadin fractions were detected by immunoblotting and independently measured by competitive indirect ELISA, using the anti-gliadin rabbit IgG.     

Mathematical approach to assessing spelt cultivars (Triticum aestivum subsp. spelt) for pasta making

This study investigates dough rheology of three wholemeal spelt flours cultivars and influence of egg quantity (0–248 g kg^?1) on the technological and sensory quality of wholemeal pasta. Standard scores (SS), based on assigning equal weight to applied parameters (rheological, chemical, technological and colour), has been calculated and the obtained values compared. Correlation coefficients of SS with alveograph data for P, L, G and W are 0.99, 0.98, 0.99 and 0.91, respectively, and warm pasta stability and retrogradation of starch correlated to SS at level 0.99. For PCA modelling, two 9 × 15 data matrices were divided into different rheological or integrated chemical, technological quality and colour evaluation methods data sets. Standard scores analysis points out that owing to its good rheology, pasta made by cultivar Austria has the best technological quality in relation to the technological quality of the other two cultivars (Nirvana and Eko).     

Development of a rapid, non-destructive method for egg content determination in dry pasta using FT-NIR technique

A quick, non-destructive method, based on Fourier transform near-infrared (FT-NIR) spectroscopy for egg content determination of dry pasta is presented. Multivariate calibration was carried out by using partial least squares (PLS) regression. A calibration set of 108 samples, a validation set of 22 samples and a prediction set of 11 samples of egg pasta were used. The diffuse reflection spectra of different types of pastas were measured by FT-NIR analyzer in the 800-2500 nm spectral range. The optimal results for egg content (root mean square error of prediction (RMSEP) = 0.7; R² = 90.7, Rank = 4) were obtained when the spectra were subjected to the first derivation combined with multiplicative scatter correction (MSC) and smoothing. Egg content was determined from FT-NIR results by introducing a mathematical correction step.     

Chemical composition, cooking quality, and consumer acceptance of pasta made with dried amaranth leaves flour

Pasta is a staple food in many countries. Amaranth is a pseudo-cereal being re-discovered because of its nutritional properties. The main objective of this study was to evaluate the potential of the green material of the amaranth plant (leaves) as a component for pasta production and its effect on the pasta quality and consumer acceptance. Dried amaranth (Amaranthus caudatus) leaves and spinach leaves flours were prepared. Pasta samples were manufactured following a small-scale pilot procedure. Amaranth pasta samples were evaluated for its chemical composition, cooking quality, textural, and sensory/consumer acceptance. Results showed that pasta made with dried amaranth leaves had similar chemical composition (protein content: 14.18 g/100 g, Fe content: 9.1 mg/100 g), cooking quality (2.15 pasta weight increase, 4.47% residue loss), textural characteristics (firmness and adhesiveness), and sensory acceptance than green pasta made with dried spinach leaves. Since amaranth leaves have similar nutritional characteristics to spinach leaves and since this biomass in not currently used for food purposes, this study points out that amaranth leaves could be technically used for pasta production and that consumer acceptance of pasta made with amaranth green leaves flour is similar to that of pasta made with spinach.     

Unripe banana flour as an ingredient to increase the undigestible carbohydrates of pasta

Banana is a starchy food that contains a high proportion of undigestible compounds, such as resistant starch and non-starch polysaccharides. There is an excess of production and large quantities of bananas are lost. The objective of this study was to use unripe banana flour as a food ingredient to make pasta (spaghetti) of high quality, on the basis of low-carbohydrate digestibility, and increased resistant starch and antioxidant phenolics contents.     

Enhancement of pasta antioxidant activity with oregano and carrot leaf

Five different pasta formulations were prepared using different concentrations of carrot leaf meal (CLM) and oregano leaf meal (OLM). One control formulation (wheat flour and semolina, 70:30 w/w) and four other formulations were prepared using the following amounts of leaf meals: 5% CLM and 5% OLM (I), 10% CLM (II), 10% OLM (III), and 10% CLM, 10% OLM (IV). The highest content of alpha-linolenic acid was found in formulations II and IV, which also had a reduced n-6/n-3 ratio, 3.6 (IV), when compared to the control, which was 19.8. All the samples enhanced with leaf meals showed antioxidant activity by the DPPH radical method; however, it was higher in formulation IV, which was the same observed for phenolic compounds. Pasta added with leaf meals lost more solubles, had shorter cooking time and a lower weight increase than the control pasta. All formulations had significant sensory acceptance.     

Modification of pasta structure induced by high drying temperatures. Effects on the in vitro digestibility of protein and starch fractions and the potential allergenicity of protein hydrolysates

The effects of drying on pasta structure, starch and protein digestibility and potential allergenicity were investigated. Pasta was dried at low (55 °C, LT), high (70 °C, HT) and very high temperature (90 °C) applied either at the beginning (VHT) or at the end of the drying profile (VHT_LM). Changes in dried and in cooked pasta structure were determined regarding protein solubility, thermal properties of starch, microscopic and rheological measurements. Changes were moderate up to 70 °C and increased at higher temperatures and especially for VHT_LM drying.     

Rheological properties of rice pasta dough supplemented with proteins and gums

Rheological properties of rice pasta dough were studied by creep-recovery tests for various formulations containing guar gum (0.5%), casein (1%), and egg white (1%) mixtures. Non-gelatinized rice semolina (RS) was also mixed with gelatinized RS in different ratios (0, 25, 50, 75 and 100%) for each formulation. The effects of gelatinization, gum and proteins on pasta dough rheology were determined by a control stress rheometer (Haake Rheostress 1). From the creep-recovery data it was obvious that as the amount of gelatinized fraction increased there was an increase in the elasticity of the samples. However, the samples that were produced with 75 and 100% gelatinized RS in the formulation were not smooth in texture, but lumpy. From the creep-recovery and dynamic oscillation measurements it was found that guar gum and protein mixture can be used as a stabilizer together with 50% pre-gelatinized rice semolina. This will result in an improvement in dough properties during gluten free pasta processing from rice.     

The effect of the incorporation of grape marc powder in fettuccini pasta properties

Several studies have been conducted to evaluate the potentiality of grape residues to be used in the food industry. In the present work, the incorporation of 25, 50 and 75 g/kg of grape marc powder in fettuccini pasta preparation was evaluated over its cooking, nutraceutical and sensory properties. The results show that the incorporation of the dried by-product did not interfere in the water absorption and in the solid loss of the pasta after cooking. The addition of grape marc powder increased the total phenolic, condensed tannins, monomeric anthocyanin and compounds antioxidant capacity concentration in the cooked pasta due to the incorporation of polyphenols stemmed from grape. Sensory analysis showed that the incorporation of grape marc powder reduced the acceptance of aroma, aftertaste, flavor and appearance, regardless of the concentration of the dried residue added. Furthermore, the incorporation of 25 g/kg of grape marc powder presented the best overall acceptance, with lower changes of color, according to the CIELAB method. Based on the results, the addition of grape marc powder to pasta is an interesting alternative of use of this by-product, potentially reflecting on final product costs and representing an environmentally friendly way to manage industrial waste.