Characterization of Rutin-rich Bread Made with ‘Manten-Kirari’, a Trace-rutinosidase Variety of Tartary Buckwheat (<i>Fagopyrum tataricum</i> Gaertn.)

Abstract

The rutin content of dough made with 'Manten-Kirari', a new Tartary buckwheat variety with tracerutinosidase activity and minimal bitterness, was assessed in a time course study of rutin hydrolysis in doughs with various water contents and blending ratios of Tartary buckwheat flour. In the normal rutinosidase variety, 'Hokkai T8', the majority of rutin was hydrolyzed within 30 min of water addition, whereas about 90% of rutin remained in 'Manten-Kirari'. We also investigated the residual rutin ratio in white bread, butter enriched roll, pound cake and galette. With 'Hokkai T8', rutin was hydrolyzed almost completely in all foods tested, whereas 88.5%, 49.8%, 31.0% and 26.2% of rutin remained in 'Manten-Kirari'-containing pound cake, white bread, butter enriched roll and galette, respectively. Also, 'Hokkai T8' bread exhibited strong bitterness, whereas 'Manten-Kirari' foods showed minimal bitterness. These results indicate that 'Manten-Kirari' is a promising material for the production of rutinrich food products without bitterness.Keywords: tartary buckwheat, rutin, rutinosidase, quercetin, bitterness IntroductionThe flavonoid rutin is widely distributed throughout the plant kingdom (Sando et al., 1924;Couch et al., 1946; Haley et al., 1954;Fabjan et al., 2003). Notably, buckwheat is the only cereal known to contain rutin in its seeds. Rutin has a number of bioactive properties, such as strengthening of blood capillaries (Griffith et al., 1944;Shanno, 1946), and antioxidative (Jiang et al., 2007;Awatsuhara et al., 2010), antihypertensive (Matsubara et al., 1985 and alpha-glucosidase inhibitory effects (Li et al., 2009). For these reasons, buckwheat has been identified as a potential rutin-rich material for use in food products (Kreft et al., 2006;Ikeda et al., 2012).Among buckwheat species, Tartary buckwheat (Fagopyrum tataricum Gaertn.) contains approximately 100-fold higher levels of rutin in seeds than that found in common buckwheat. However, Tartary buckwheat seeds also display rutinosidase activity (Fig. 1), which is sufficiently high to hydrolyze the rutin present in buckwheat flour (approximately 1% _ 2% [w/w]) within a few minutes after the addition of water (Yasuda et al., 1992;Yasuda et al., 1994;Suzuki et al., 2002). Tartary buckwheat rutinosidase activity is attributable to at least two isozymes that possess similar characteristics (Yasuda et al., 1992, Yasuda et al., 1994, Suzuki et al., 2002, Suzuki et al., 2004. The investigation of rutin hydrolysis in foods such as bread and confectionaries has revealed that the majority of rutin contained in these foods is hydrolyzed as a result of rutinosidase activity (Brunori et al., 2010;Vogrincic et al., 2010;Brunori et al., 2013). In addition to possessing rutinosidase activity, the flour of Tartary buckwheat, also known as 'bitter buckwheat', is highly bitter, thereby limiting its potential use in food products. At least three bitter compounds have been reported in Tartary buckwheat dough (Kawakami, et al., 1995), and the mechanisms responsible for gene...

Breeding buckwheat for nutritional quality

“…By scalding TB flour with hot water, a considerable amount of rutin is conserved from flour through the process to the final bread product (Lukšič et al 2016). Suzuki et al (2002Suzuki et al ( , 2014Suzuki et al ( , 2015aSuzuki et al ( , 2015bSuzuki et al ( , 2015c used new trace-rutinosidase TB variety to produce wheat-TB combined bread with considerable amount of rutin, preserving about 50% of the initial rutin from TB flour in the bread. Trace-rutinosidase TB may become more popular in Japan.…”

Effects of hydrothermal processing on rutin retention and physicochemical properties of Tartary buckwheat enriched dough and Chinese steamed bread

“…Hydrothermal processing at 100°C for 30 min and 121°C for 20 min or 30 min resulted in significantly decreased specific volumes of TB enriched CSB, with processing at 100°C for 30 min and 121°C for 10, 20 or 30 min leading to markedly increased hardness of CSB. Smaller specific volumes (Suzuki et al, 2015;Piasecka-j o zwiak et al, 2016) and increased hardness (Piasecka-j o zwiak et al, 2016) were also found in buckwheat enriched breads. Compared with control, the bitterness of CSB was sensitive to hydrothermal processing and decreased dramatically with processing time and temperature.…”

Spremembe vsebnosti rutina in kvercetina v vzorcih tatarske ajde (Fagopyrum tataricum (L.) Gaertn.) od spravila pridelka do priprave kruha / Changes in the content of rutin and quercetin in samples of Tartary buckwheat (Fagopyrum tataricum (L.) (...)

“…Za nobeno drugo metodo priprave kruha iz moke tatarske ajde ni znano, da bi se med postopkom priprave kruha ohranilo toliko rutina. Suzuki et al (2015) so nedavno poročali o tem, da so ob uporabi tatarske ajde s samo sledovi rutinozidaze pripravili kruh iz mešanice moke te tatarske ajde in pšenice z 0,63 mg/g rutina, kar predstavlja približno 50 % delež ohranjenega rutina v kruhu, v primerjavi z izvorno surovino (moko). Wieslander et al (2011) so poročali o koncentraciji 2,5 mg/g rutina prisotnega v piškotih, pripravljenih iz moke tatarske ajde.…”