Tomoko Maeda’s research while affiliated with Hyogo University of Teacher Education and other places

High-amylose wheat was subjected to various germination conditions and changes in its nutritional values and antioxidant capacity were investigated. Amounts of soluble dietary fiber, total protein and free lipid of germinated high-amylose wheat increased with increased germination times, whereas no significant changes were observed for insoluble dietary fiber and free fatty acids. Total free amino acid contents of high-amylose wheat gradually increased from 129.7 to 314.4 mg/100 g of grain (db) during 48 h of germination. As compared to ungerminated wheat, essential and functional amino acids including isoleucine, leucine, phenylanaline, valine and gamma-amino butyric acid in the 48 h-germinated wheat increased by 3–10 times. Total phenolic contents of both free and bound phenolics and their antioxidant capacities significantly increased after 24 h of germination and were further improved with prolonged germination times. It appears that nutritional values and bioactive compounds of high amylose wheat significantly improved for enhanced food applications.

BACKGROUND: Germination is considered to improve the nutritive value, antioxidant capacity and functional properties of grains. In this study, changes in the chemical composition, nutritive value and antioxidant capacity of waxy wheat during germination were determined. RESULTS: Over a 48 h period of germination the protein and free lipid contents of germinated waxy wheat were not significantly different from those of the control, whereas the bound lipid content decreased significantly. An increase in levels of ash and dietary fibre was clearly observed for the 48 h-germinated wheat. The total free amino acid content of the 48 h-germinated wheat was 7881 mg kg−1 flour (dry basis (d.b.)), significantly higher than that of the ungerminated wheat (2207 mg kg−1 flour, d.b.). In particular, γ-aminobutyric acid increased from 84 mg kg−1 flour (d.b.) in the control to 155 mg kg−1 flour (d.b.) in the 48 h-germinated wheat. Germination did not significantly affect the fatty acid composition of both free and bound lipids of waxy wheat, whereas free phenolic compounds increased during germination, resulting in an increase in antioxidant capacity of germinated wheat. CONCLUSION: Germinated waxy wheat had a better nutritional composition, such as higher dietary fibre, free amino acid and total phenolic compound contents, than ungerminated waxy wheat. Therefore germinated waxy wheat should be used to improve the nutritional quality of cereal-based products. Copyright

Antioxidative activities of E- and Z-ajoene prepared from Japanese garlic were studied using various radical scavenging effects. Among the various antioxidative activities tested, ajoene was found to show the highest hydroxyl radicals scavenging activity (E-ajoene = 50% and Z-ajoene = 63%). These ajoene were 5.2-13 times less efficient at reducing DPPH radical and 1.1-1.4 times less efficient at hydroxyl radical as compared with authentic α–tocopherol. Essentially E- and Z-ajoene were capable of scavenging superoxide anion (E- ajoene = 0.11%, Z-ajoene = 3.74%), but 80 minutes later antioxidant activity could not be detected. The effectiveness of Z-ajoene is significantly higher than E-ajoene.

Application of ajoene to mayonnaise and its stability were studied. Addition of 5, 10, 15, 20, 25 and 30% garlic oil containing ajoene to mayonnaise recovered E-ajoene 47.7–62.4 μg/10g mayonnaise and Z-ajoene 42–74 μg/10g mayonnaise. After one month storage 99% E- and Z-ajoene remained. In 20% substituted mayonnaise 72% and 69% E- and Z-ajoene respectively were obtained at 80oC. After three days incubation under UV-light and fluorescent light, 92% and 98% E-ajoene; 88% and 98% Z-ajoene respectively remained. Sensory evaluation demonstrated that, 20% substituted mayonnaise was the highest score among others.

The graded flour fractions, which were milled from whole wheat grain from outer to inner parts without removal of germ and bran, are rich in dietary fibers and minerals, the sources of nutrition for human beings. In this study, the whole waxy wheat was milled into five fractions using the gradual milling method and the phenolic contents and antioxidant capacity of these flours were investigated. The total phenolic and flavonoid contents of free and bound phenolic extracts gradually increased in the order from the inner to the outer fractions. The flours milled from the outer parts of grain contained significantly higher amount of phenolics and exhibited significantly higher antioxidant capacity than did the whole grain. Likewise, the inner flour fractions milled from mostly endosperm part had significantly higher amount of phenolics and exhibited significantly higher antioxidant capacity than did the white flour, which was milled by a conventional milling method. Thus, the graded flours from whole waxy wheat should be encouraged to be used for processing whole-grain foods to improve both qualities of end-use products and health benefits.

Flavor compounds are one of the very important factors for the taste of commercial breads, and then the volatile flavor compounds in the present novel polished-wheat-flour breads were determined by headspace sorptive extraction method to develop the baking properties, comparing two baking procedures of straight-common- and sourdough-methods. The polished flours of outermost, middle and innermost fractions, and common flour, CW were used. There were some differences on the compounds and proportions of volatile flavors in all flours between the both methods. The sourdough-method increased the proportions of acids and aldehydes in crust, but decreased those of alcohols and methoxybenzenes identified in the outermost fraction, rather than the straight-common-method. In addition, the sourdough-method lowered the amounts of some compounds related to oxidation products from unsaturated fatty acids and metabolites of species with moldy grains, as compared with the straight-common-method. Furthermore, the amounts of 2-methylpropanol (iso-butanol) and 2-phenylethanol (β-phenyl-ethyl-alcohol) that have been known as favorable flavor compounds on breadmaking distinctly increased in polished flour breads than CW bread, regardless of baking methods. Therefore, the sourdough-method with lactic acid fermentation would be suitable baking procedure for polished flours from the viewpoints of flavor properties. Furthermore, the utilization of sourdough-method for polished flours from middle and innermost fractions might be appropriate to taste and texture of consumers’ request for bread qualities.

Rheological properties of dough and bread quality of frozen dough-bread containing 18.4% of hydroxypropylated (HTS), acetylated (ATS), and phosphorylated cross-linked (PTS) tapioca starch with different degrees of modification and 1.6% of dried powdered gluten were compared to the same amount of native tapioca starch (NTS) or wheat flour-bread. Doughs substituted with native or modified tapioca starches had the same mixing tolerance as 100% wheat flour. The dough was frozen and stored for 1week at −18°C, and thawed (one freeze-cycle). The amount of freezable water in the dough substituted with native or modified tapioca starches was not significantly different from that of wheat flour. Frozen dough-bread substituted with highly modified HTS (degree of substitution; DS 0.09–0.11) retarded bread staling, while lowly modified HTS (DS 0.06–0.07) or ATS (DS 0.02–0.04), and PTS (0.004–0.020% phosphoryl content) substitution fastened bread staling as compared with frozen dough-bread baked from wheat flour. The breadcrumbs containing HTS and ATS felt tacky, whereas the bread containing PTS was dry feel. HTS and ATS swelled and collapsed easily during heating, while PTS was difficult to swell and disperse as compared with NTS, therefore the gelatinization properties seemed to affect the texture of bread. Breadcrumb containing HTS showed small firmness during storage, and highly modified HTS-h (DS 0.1) was the smallest. This means highly hydroxypropylated tapioca starch significantly retards bread staling. Staling properties and texture of frozen dough-bread with various tapioca starches were the same as conventional bread baked with the same amount of tapioca starches. These results suggest that a one freeze–thaw cycle and a 1-week frozen period do not change characteristics of starch, gelatinization and retrogradation properties as compared with the conventional method, and the highly modified HTS-h is prominent anti-staling food-stuff in frozen dough.

Hypoallergenic wheat flour was produced by polished-graded method using a rice polishing machine. Eight fractions (C1–C8) of polished-graded wheat flours were obtained step wise from the outer layer of whole wheat grains by 10% of the total weight, and the distribution of allergenic protein in each fraction was determined. The salt-soluble (albumin/globulin), salt-insoluble (glutenin) and alcohol-soluble (gliadin) proteins obtained from the polished-graded wheat flours were tested for the allergen assay with immunodetection using the sera of wheat allergenic patients. Immunoblotting results confirmed that the innermost fraction (C8) contained a smaller amount of allergenic proteins. Albumin/globulin groups in all fractions (C1–C8) showed different IgE-reactivity patterns, the 60–75 kDa proteins appeared in all of fraction flours. It was higher in C3–C5 fractions. Fractions C3 and C4 contained higher amount of specific wheat allergenic protein including 60–75, 35, 22, and < 20 kDa. IgE-antibody also bound to glutenin (25–37 kDa), especially in C3 and C4, but the binding proteins showed quite faint bands. Gliadin was found in all fractions of wheat flour. We propose that polishing is an appropriate method to obtain hypoallergenic wheat flours, and the fraction C8 may be possible to be consumed by people suffering from wheat allergy.

High-amylose starch is a source of resistant starch (RS) which have great impact on human health like dietary fiber. Nowadays, high-amylose wheat has been produced by genetic backcrossing, which enhances apparent amylose content and generates altered amylopectin. In this study, the high-amylose wheat starches isolated from various high-amylose wheat cultivars grown in Australia were characterized for understanding their physicochemical properties and fine structure of starch. The physicochemical characteristics of the high-amylose wheat starches are significantly different among the cultivars. Amylose contents of these cultivars were in a range of 28.0–36.9%, which is significantly higher than that of the normal wheat starch (25.6%). The high-amylose wheat starches also had higher blue value but lower λmax than the normal wheat starch. Gelatinization temperature of the high-amylose wheat starches is higher than that of the normal wheat starch but transition enthalpy is lower. X-ray diffraction showed that the high-amylose wheat starch had C-type crystals close to A-type crystal. Pasting properties of the high-amylose wheat starches were varying depending on the cultivars. However, almost high-amylose wheat starches had lower peak and final viscosities and higher setback viscosity than did the normal wheat starch. Fine structure of amylose and amylopectin was different among the high-amylose wheat cultivars and related to the physicochemical properties of starch. These results help to understand well the characteristics of the high-amylose wheat starches before application for food processing.