Role of superfine grinding in whole-purple-wheat flour. Part II: Impacts of size reduction on dough properties, bread quality and in vitro starch digestion.

This study aimed to enhance bread functionality while maintaining its organoleptic attributes by employing superfine grinding and purple wheat, through characterizing dough properties, bread quality attributes, and in vitro starch digestibility. Compared with dough made from commercial-superfine-whole-wheat flour, the superfine-whole-purple-wheat dough was less strong, comparably extensible, and higher in gassing power during mixing, moulding and proofing, respectively. The subsequent bread quality analysis of crumb grain features and texture indicated that the bread made from superfine-whole-purple-wheat flour was more porous and softer with a larger specific volume (3.21 ± 0.20 cm3/g) than that made from commercial-superfine-whole-wheat flour (2.30 ± 0.17 cm3/g). Additionally, the superfine-whole-purple-wheat bread had a significantly slower glucose release (k = 0.0048 min-1) during in vitro starch digestion as compared to the superfine-whole-wheat bread (k = 0.0065 min-1). Therefore, this study demonstrates that using superfine-whole-purple-wheat flour leads to bread with desirable quality attributes and potential health benefits compared to conventional whole-wheat flour.

Mass spectrometry-based quantification of immunostimulatory gliadin proteins and peptides in coloured wheat varieties: Implications for Celiac Disease.

Pigmented wheat varieties (Triticum aestivum spp.) are getting increasingly popular in modern nutrition and thoroughly researched for their functional and nutraceutical value. The colour of these wheat grains is caused by the expression of natural pigments, including carotenoids and anthocyanins, that can be restricted to either the endosperm, pericarp and/or aleurone layers. While contrasts in phytochemical synthesis give rise to variations among purple, blue, dark and yellow grain's antioxidant and radical scavenging capacities, little is known about their influence on gluten proteins expression, digestibility and immunogenic potential in a Celiac Disease (CD) framework. Herein, it has been found that the expression profile and immunogenic properties of gliadin proteins in pigmented wheat grains might be affected by anthocyanins and carotenoids upregulation, and that the spectra of peptide released upon simulated gastrointestinal digestion is also significantly different. Interestingly, anthocyanin accumulation, as opposed to carotenoids, correlated with a lower immunogenicity and toxicity of gliadins at both protein and peptide levels. Altogether, this study provides first-level evidence on the impact modern breeding practices, seeking higher expression levels of health promoting phytochemicals at the grain level, may have on wheat crops functionality and CD tolerability.

Anthocyanin Content and Fusarium Mycotoxins in Pigmented Wheat (Triticum aestivum L. spp. aestivum): An Open Field Evaluation.

Twelve Triticum aestivum L. spp. aestivum varieties with pigmented grain, namely one red, six purple, three blue, and two black, were grown in open fields over two consecutive years and screened to investigate their risk to the accumulation of multiple Fusarium-related mycotoxins. Deoxynivalenol (DON) and its modified forms DON3Glc, 3Ac-DON, 15Ac-DON, and T-2, HT-2, ZEN, and Enniatin B were quantified by means of UHPLC-MS/MS, along with 14 different cyanidin, petunidin, delphinidin, pelargonidin, peonidin, and malvidin glycosides. A significant strong influence effect of the harvesting year (p = 0.0002) was noticed for DON content, which was more than doubled between harvesting years growing seasons (mean of 3746 µg kg-1 vs. 1463 µg kg-1). In addition, a striking influence of varieties with different grain colour on DON content (p < 0.0001) emerged in combination with the harvesting year (year×colour, p = 0.0091), with blue grains being more contaminated (mean of 5352 µg kg-1) and red grain being less contaminated (mean of 715 µg kg-1). The trend was maintained between the two harvesting years despite the highly variable absolute mycotoxin content. Varieties accumulating anthocyanins in the pericarp (purple coloration) had significantly lower DON content compared to those in which aleurone was involved (blue coloration).

Nutritional Features and Bread-Making Performance of Wholewheat: Does the Milling System Matter?

Despite the interest in stone-milling, there is no information on the potential advantages of using the resultant wholegrain flour (WF) in bread-making. Consequently, nutritional and technological properties of WFs obtained by both stone- (SWF) and roller-milling (RWF) were assessed on four wheat samples, differing in grain hardness and pigment richness. Regardless of the type of wheat, stone-milling led to WFs with a high number of particles ranging in size from 315 to 710 µm), whereas RWFs showed a bimodal distribution with large (>1000 µm) and fine (<250 µm) particles. On average, the milling system did not affect the proximate composition and the bioactive features of WFs. The gluten aggregation kinetics resulted in similar trends for all SWFs, with indices higher than for RWFs. The effect of milling on dough properties (i.e., mixing and leavening) was sample dependent. Overall, SWFs produced more gas, resulting in bread with higher specific volume. Bread crumb from SWF had higher lutein content in the wheat cv rich in xanthophylls, while bread from RWF of the blue-grained cv had a moderate but significantly higher content in esterified phenolic acids and total anthocyanins. In conclusion, there was no relevant advantage in using stone- as opposed to roller-milling (and vice versa).

Antioxidant Properties of Sourdoughs Made with Whole Grain Flours of Hull-Less Barley or Conventional and Pigmented Wheat and by Selected Lactobacilli Strains.

The use of sourdough fermentation and whole grain flours in baked goods manufacturing are known to enhance their functional and nutritional features. In this context, it is necessary to select the most suitable lactic acid bacteria strains and flour combination to achieve this goal. A characterization of 70 lactobacilli strains based on pro-technological and nutritional properties was carried out. The screening allowed the selection of 10 strains that were used to ferment sourdoughs made with two varieties of common wheat, the conventional red-grained cv Aubusson, a blue-grained variety rich in anthocyanins cv Skorpion, and a hull-less barley variety, cv Rondo. From each fermented sourdough, a water soluble extract was obtained and evaluated for its antioxidant activity performed on cultured cells (RAW 264.7 murine macrophage) by assaying Reactive Oxygen Species (ROS) content. Sourdoughs made with pigmented wheat and barley, had an antioxidant activity greater than that recovered in those made with conventional wheat flour, in spite they have been inoculated with the same LAB strains. Results highlighted the interdependence between flour and the inoculated lactic acid bacteria that has to be taken into account for the development of healthy breads exploiting high functional value cereals through biotechnological processes.

Bio-Functional and Structural Properties of Pasta Enriched with a Debranning Fraction from Purple Wheat.

A colored and fiber-rich fraction from the debranning of purple wheat was incorporated at 25% into semolina- and flour-based pasta produced on a pilot-plant scale, with the aim of increasing anthocyanin and total phenolic content with respect to pasta obtained from whole pigmented grains. The debranning fraction impaired the formation of disulfide-stabilized protein networks in semolina-based systems. Recovery of phenolics was impaired by the pasta making process, and cooking decreased the phenolic content in both enriched samples. Cooking-related losses in anthocyanins and total phenolics were similar, but anthocyanins in the cooked semolina-based pasta were around 20% of what was expected from the formulation. HPLC (High Performance Liquid Chromatography) profiling of phenolics was carried out on extracts from either type of enriched pasta both before and after cooking and indicate possible preferential retention of specific compounds in each type of enriched pasta. Extracts from cooked samples of either enriched pasta were tested as inhibitors of enzymes involved in glucose metabolism and uptake, as well as for their capacity of suppressing the response to inflammatory stimuli. Results of both biological tests indicate that the phenolics in extracts from both cooked pasta samples had inhibitory capacities higher than extracts of the original debranning fraction at identical concentrations of total bioactives.