• Korean Journal of Medicinal Crop Science
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• v.27 no.2
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• pp.108-114
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• 2019

Background: Rutin is decomposed by rutin-degrading enzymes (RDE) during the processing of buckwheat groats, resulting in a decrease in rutin content and a further increase in the bitterness of processed products. Thus, the present study aimed to examine RDE activity in groats and various tissues of domestic buckwheat varieties and to develop a method to reduce the loss of rutin during the groat processing. Methods and Results: RDE activity and isozymes patterns were determined in Tartary and common buckwheat. RDE activity, measured by quercetin production rate, was 273 and $70{\mu}g/g$ fresh weight/min in mature Tartary and common buckwheat groats, respectively. A total of six RDE isozymes were detected in mature groats of Tartary buckwheat on a non-denaturing gel. In Tartary buckwheat groats, RDE activity decreased by approximately 81 or 71% with roasting or steaming for 5 min respectively. As the roasting or steaming time increased to 30 min, RDE activity decreased by over 95%. These results indicated that RDE was inactivated in groats by roasting or steaming. When untreated Tartary buckwheat groats were kneaded with powder, RDE was activated and the quercetin production rate increased by 62%. However, when roasted groats were kneaded with powder, the quercetin production rate decreased by 93%, mainly due mainly to inactivation of RDE, as indicated by a decrease in band intensities of the six isozymes. Conclusions: These results suggested that the loss of rutin, due to RDE activity during processing, may be reduced by 71 to 100% by roasting or steaming groats for 5 to 30 min, due in large part to the inactivation of RDE isozymes.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.271-271
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• 2017

Tartary buckwheat is known for its high rutin (quercetin 3-rutinoside) content which has antioxidant, anti-inflammatory, and anticarcinogenic effects. The buckwheat tea which is popular in Korea, is dependent on the quality of applied processing methods (steaming, dehuling, and roasting). This study focused on the evaluation of changes in rutin and anti-oxidant contents during the processing of tartary buckwheat tea. Raw tartary buckwheat seeds contains the highest quantities of rutin (2,212 mg/100 g D.W.). Soaking in water and steaming the whole seeds of tartary buckwheat significantly decreased its rutin and quercetin contents. Whereas the contents of rutin and quercetin in dehulled groats increased after steaming. The process of roasting with $70-80^{\circ}C$ for 2-3 min significantly decreased the contents of rutin (992 mg/100 g D.W.) and quercetin (12.8 mg/100 g D.W.). In the processing of tartary buckwheat tea, rutin content dropped about 45% in comparison with raw whole seeds.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.2
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• pp.219-226
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• 2007

This study was conducted to compare the quality of steamed cakes supplemented with common buckwheat(F. esculentum Miench.) and tartary buckwheat(F. tartaricum Gaetn). A proximate analysis, and rutin content, color value, texture characteristics and sensory evaluations were performed, In the proximate analysis, the steamed buckwheat as opposed to raw buckwheat, appeared to afford higher values for most of the evaluated items. The rutin content of the tartary buckwheat was over 14 times higher than that of common buckwheat and remained about 58% higher after steaming. The lightness of the steamed cakes was in the following order: control(wheat flour only), with the addition of common buckwheat, and with the addition of tartary buckwheat. The redness and yellowness increased in the following order: tartary buckwheat, common buckwheat, control steamed cake. There were no significant differences in the springiness of steamed cake between the various samples including the control: therefore, resulted in good quality during bread-making. In the sensory evaluation, on increasing the amount of tartary buckwheat addition the score for entire taste increased compared with common buckwheat and the control and also had positive results for all other items, including flavor, color, softness and moistness. This study has suggested the ability to make steamed cakes containing tartary buckwheat flour.

• Food Science and Biotechnology
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• v.17 no.1
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• pp.118-122
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• 2008

The use of tartary buckwheat flour as a source of dietary rutin has been limited because of the enzymatic degradation of rutin during the dough-making process, which results in a bitter taste. A variety of pretreatment regimes, including heating, steaming, boiling, and extruding, were evaluated in relation to the inactivation of the rutin-degrading enzyme responsible for rutin loss and color change during dough-making. Steaming (120 see), boiling (90 see) buckwheat grains, or extruding (180 rpm/min at $140^{\circ}C$) the flour resulted in the retention of >85% of the original rutin and eliminated the bitter taste in the hydrated flours. In contrast, dry heating at $140^{\circ}C$ for 9 min or microwaving at 2,450 MHz for 3 min did not reduce the rutin loss, and the bitter taste remained. Unlike in the flour, the rutin degradation in water-soaked grains was insignificant at room temperature. Moreover, the samples treated by steaming, boiling, or extrusion were darker and more reddish in color.