In this study, the chemical composition of pigmented wheats (yellow, purple and blue types), and the distribution of the bioactive compounds in their roller-milled and pearled fractions, were compared with conventional wheats (red and white types). Roller-milling promoted the recovery of total dietary fiber, β-glucans, phenolic acids and anthocyanins in the bran fraction, which resulted also in a higher total antioxidant activity than the refined flour. Conversely, lutein resulted mainly concentrated in the refined flour. In the same way, the distribution pattern in the pearled fractions differ depending on the bioactive considered. The study highlights that a careful selection of the most appropriate fractionation process should be performed to produce flours rich in bioactive compounds. Roller-milling resulted useful for the production of refined flours rich in xanthophylls, with particular emphasis to the yellow-grained wheats. Contrarily, pearling could be more useful in the valorization of the health potential of anthocyanin-pigmented varieties.

No abstract

Mycotoxins and other fungal metabolites represent the most insidious safety risks to cereal food and the feed chain. Optimising agronomic practices is one of the main strategies adopted to minimise the contents of these undesirable substances in grain-based commodities. The aim of this study was to investigate the effect of the combination of sowing times and hybrids on the occurrence of emerging mycotoxins and fungal metabolites in maize. Field experiments were carried out in 2 sowing times (early vs late) and 3 maize hybrids were compared in the 2014 and 2015 growing seasons. Overall, 37 fungal metabolites produced by Fusarium and Alternaria species were detected. Apart from fumonisins type B (FBs), other metabolites produced by Fusarium verticillioides and F. proliferatum, such as fumonisins type A, fusaric acid, bikaverin and fusaproliferin, were also detected in all of the samples. Fusarin C was found in 61% of the samples. Deoxynivalenol (DON), deoxynivalenol-3-glucoside, culmorin and zearalenone, all of which are produced prevalently by Fusarium graminearum and F. culmorum, were found in all the samples. Their contents were clearly affected by the meteorological trend: the highest contamination was detected in the 2014 growing season, which was characterised by abundant rainfall and lower temperatures from flowering to maize ripening. Among the mycotoxins produced by other Fusarium species, aurofusarin was found to clearly be associated with DON, while moniliformin and beauvericin followed the same behaviour as the FBs.A late sowing time significantly increased the FBs and fumonisin-associated mycotoxins in both growing seasons. The increase in contamination with the delay of sowing was more pronounced in the 2015 growing season, as the environmental conditions were less favourable to the infection of other Fusarium species. The effect of sowing time on DON and DON-associated mycotoxins produced conflicting results for the two growing seasons, because contamination by these metabolites depends more on the conditions that occur during maize flowering than those that occur during ripening. A clearer hybrid susceptibility was observed for these compounds. Other metabolites, such as enniatins, equisetin, T-2 and HT-2 toxins and Alternaria toxins, were always found in traces. The occurrence of these metabolites seems to be influenced less by the considered agronomic practices.The results, obtained under naturally-infected field conditions, underline the key role that the sowing date and hybrid susceptibility play in influencing, in a variable way, the contamination of mycotoxins produced by different Fusarium species in maize subjected to different meteorological conditions. The content of mycotoxins produced by Fusarium spp. section Liseola is more directly and steadily related to late sowing time, while the contamination of mycotoxins associated to Fusarium spp. section Discolor depends more strongly on the environmental conditions at maize flowering and on hybrid susceptibility.

The increasing demand for healthy baked goods boosted studies on sourdough microbiota with beneficial metabolic traits, to be used as potential functional starters. Here, 139 yeasts isolated from cereal-based fermented foods were in vitro characterized for their phytase and antioxidant activities. The molecular characterization at strain level of the best 39 performing isolates showed that they did not derive from cross contamination by baker's yeast. Afterwards, the 39 isolates were in vivo analyzed for their leavening ability, phytase activity and polyphenols content using five different wholegrain flours, obtained from conventional and pigmented common wheat, emmer and hullless barley. Combining these findings, through multivariate permutation analysis, we identified the 2 best performing strains, which resulted diverse for each flour. Doughs singly inoculated with the selected strains were further analyzed for their antioxidant capacity, phenolic acids, xanthophylls and anthocyanins content. All the selected yeasts significantly increased the total antioxidant activity, the soluble, free and conjugated, forms of phenolic acids and anthocyanins of fermented doughs. This study revealed the importance of a specific selection of yeast strains for wholegrain flours obtained from different cereals or cultivars, in order to enhance the pro-technological, nutritional and nutraceutical traits of fermented doughs. Fermentation is one of the oldest methods used by humans since ancient times for preserving foods and improving their organoleptic properties. More than 5,000 fermented foods and beverages are produced all over the world, from wine, beer and vinegar to cheese, yogurt, sourdough bread, olives, sausages, kimchi and miso 1. Fermentation consists of the biochemical modification of raw materials, promoted by a complex and stable consortium of microorganisms, which mainly transform sugars into simple acids, alcohols and carbon dioxide, improving flavor, texture and aroma, and prolonging the shelf-life of the fermented products 2. During fermentation, a wide range of secondary metabolites, including vitamins, polyols, antioxidants and bioactive compounds are also produced by microbial communities, enhancing the nutritional and nutraceutical values of the final products 3. Among fermented foods, sourdough bread is one of the most important baked goods derived from cereal fermentation 4. The estimated annual pro capita intake of bread in European countries is reported to range from 46 (Sweden, Great Britain, Finland and Austria) to 100 kg (Greece, Portugal, Spain and Italy) 5 , and about 30 to 50% of bread is manufactured using sourdough 6. Sourdough is a mixture of cereal flour and water, fermented by a complex biological ecosystem, consisting of lactic acid bacteria (LAB) and yeasts which interact with each other, often establishing stable associations and contributing to the beneficial properties of sourdough breads 7. Each sourdough harbors different LAB and yeast communities, whose diversity depends on the type o...

Cereal Chem. 94(2):315-324Corn grain production could be affected by several fungal pathogens responsible for the production of mycotoxins. The aims of this study were to determine the evolution of phenolic acids and total antioxidant activity (TAA) during kernel development and to evaluate their potential protective role in minimizing mycotoxin contamination in six corn genotypes (four open-pollinated varieties and two hybrids) characterized by a wide array of kernel traits. TAA and free and cell wall-bound phenolics showed significant differences among corn genotypes at different stages of development, with the highest values found at the beginning of kernel development. Ferulic, p-coumaric, and caffeic acids were the main cell wall-bound phenolic acids during kernel development, whereas chlorogenic acid was the main free phenolic acid. A significant negative correlation was observed between deoxynivalenol contamination at harvest maturity and free phenolic acids and TAA at the beginning of kernel development, whereas no significant correlation was observed with fumonisin contamination. In conclusion, free phenolic acids are evidently involved in the resistance mechanism toward deoxynivalenol contamination, whereas their role toward fumonisin contamination was not elucidated under field conditions, implying that components other than phenolic acids may be responsible for this latter type of resistance.

No abstract

This study focused on the suitability of corn milling fractions (break meal, particle size: 250-500 µm; flour, particle size < 150 µm) from hybrids different in amylose content (conventional: 18% amylose; high-amylose: 42% amylose; waxy: 2% amylose) and their blends, to produce coextruded snacks. Antioxidant capacity, phenolic acid content, pasting properties and snack size, hardness, porosity, and density were considered. As regards the bioactive compounds, corn flour reported a marked antioxidant capacity compared to break meal. High amylose hybrid maintained the highest antioxidant capacity and phenolic acid content even after extrusion. Waxy and conventional hybrids led to more expanded and softer snacks, than the high amylose hybrid that, thus, has to be preferred for co-extruded snacks production. Blends led to snacks whose features did not follow a linear trend with the amylose content, suggesting the need for further studies to better understand starch interactions among the various hybrids.

Drought stress affects anthocyanin accumulation and modification in vegetative and reproductive plant tissues. Anthocyanins are the most abundant flavonoids in grape (Vitis vinifera L.) coloured berry genotypes and are essential markers of grape winemaking quality. They are mostly mono- and di-methylated, such modifications increase their stability and improve berry quality for winemaking. Anthocyanin methylation in grape berries is induced by drought stress. A few caffeoyl-CoA O-methyltransferases (CCoAOMTs) active on anthocyanins have been described in grape. However, no drought-activated O-methyltransferases have been described in grape berries yet. In this study, we characterized VvCCoAOMT, a grapevine gene known to induce methylation of CoA esters in cultured grape cells. Transcript accumulation of VvCCoAOMT was detected in berry skins, and increased during berry ripening on the plant, and in cultured berries treated with ABA, concomitantly with accumulation of methylated anthocyanins, suggesting that anthocyanins may be substrates of this enzyme. Contrary as previously observed in cell cultures, biotic stress (Botrytis cinerea inoculation) did not affect VvCCoAOMT gene expression in leaves or berries, while drought stress increased VvCCoAOMT transcript in berries. The recombinant VvCCoAOMT protein showed in vitro methylating activity on cyanidin 3-O-glucoside. We conclude that VvCCoAOMT is a multifunctional O-methyltransferase that may contribute to anthocyanin methylation activity in grape berries, in particular under drought stress conditions.