Ultrasound-Assisted Germination of Buckwheat: Impact on Anti-nutritional and Antioxidant Content

Abstract

Buckwheat is a highly nutritious grain that contains macro and micronutrients with antioxidant potential. However, some anti-nutritional components in buckwheat, such as phytic acid and condensed tannins, reduce its bioavailability. Germination is an ancient and natural method to improve the nutritional value of cereal grains. Controlled germination processes increase the nutritional value of pseudocereals by reducing the amount of antinutrients. Thus, the bioavailability of nutrients improved. Ultrasound-assisted germination can be a good alternative for increasing nutritional and bioactive values and mitigating the anti-nutritional properties of buckwheat by accelerating enzyme activity and biochemical changes by affecting the cell membrane structure. This study investigated the changes in chemical composition, phenolic content, antioxidant activity, color, and anti-nutrient content of buckwheat grains (Fagopyrum esculentum Moench. cv. Aktaş) germinated for 72 hours by traditional and ultrasound-assisted methods. The highest total phenolic content (498.572.93 mg GAE 100 g-1) and antioxidant activity (10.911.62 mol TEAC g-1) of buckwheat were measured in the germinated sample using the ultrasound-assisted method. However, the color changes were not notable during 72 h of germination. The lipid (3.06 – 3.39%) and protein contents (12.56 – 15.05%) were increased after germination. The starch content was 58.58% in ungerminated buckwheat and decreased (52.36%) after 72 h of germination using the ultrasound-assisted method. In germinated samples, tannin content was reduced by 43 – 54%, whereas a slight reduction was observed in phytic acid concentrations. Ultrasound-assisted germination can be a valuable alternative to improve the chemical composition and bioactive potential and mitigate the anti-nutritional properties of buckwheat grains. Germinated grain, flour, or processed products might be good alternatives to traditional cereal consumption because of their improved functional properties.

Keywords

• Aktaş
• Total phenolic content
• Antioxidant Activity
• Tannin
• Sprouting
• Ultrasoud

Karabuğdayın Ultrases-Destekli Çimlendirilmesi: Anti-Besinsel ve Antioksidan Bileşenler Üzerine Etkisi

Abstract

Karabuğday antioksidan potansiyele sahip makro ve mikro besin elementleri açısından zengin bir pseudo-tahıldır. Fakat bileşiminde bulunan fitik asit ve kondanse tanenler gibi bazı anti-besinsel bileşenler karabuğdayın biyoyararlanımını azaltmaktadır. Çimlendirme tahıl tanelerinin besin değerinin artırılmasında eski ve doğal yollardan biridir. Kontrollü çimlendirme prosesleri, anti-besinsel bileşen konsantrasyonunu azaltarak pseudo-tahılların besin değerini artırmakta ve böylece besinlerin biyoyararlılığını iyileştirmektedir. Ultrases dalgaları enzim aktivitesini hızlandırırken hücre membran yapısını da etkileyerek kimyasal değişimlere neden olmaktadır. Bu nedenle, ultrases destekli çimlendirme işlemi besinsel ve biyoaktif özelliklerin artırılması ve anti-besinsel özelliklerin azaltılması için iyi bir alternatif olabilir. Bu çalışmada, karabuğday (Fagopyrum esculentum Moench. var. Aktaş) geleneksel ve ultrases destekli yöntemlerle 72 saat süresince çimlendirilmiştir. Çimlendirme süresince kimyasal kompozisyondaki değişimin yanı sıra anti-besinsel bileşenler, toplam fenolik madde miktarı, antioksidan aktivite ve renk değerlerindeki değişim de incelenmiştir. Çimlendirme işlemi sonrasında en yüksek toplam fenolik madde miktarı (498.57  2.93 mg GAE 100 g-1) ve antioksidan aktivite (10.91  1.62 mol TEAC g-1) ultrases destekli çimlendirilen karabuğday örneklerinde ölçülmüştür. Buna karşın 72 saatlik çimlendirme sürecinde renk değerlerinde belirgin bir değişim gözlenmemiştir. Karabuğday tanesinde çimlendirme sonucunda yağ (%3.06 – 3.39) ve protein (%12.56 – 15.05) konsantrasyonu artmıştır. Çimlendirilmemiş karabuğdayda nişasta konsantrasyonu %58.58 olarak belirlenirken ultrases destekli çimlendirme yöntemi kullanılan örneklerde 72 saat sonunda nişasta konsantrasyonu (%52.36) azalmıştır. Tanen miktarı ise %43 – 54 düzeyinde azalırken fitik asit miktarında daha sınırlı bir azalış olduğu belirlenmiştir. Ultrases destekli çimlendirme yönteminin, tahıl tanesinin kimyasal kompozisyonunun iyileştirilmesi, biyoaktif potansiyelin artırılması ve anti-besinsel özelliklerin azaltmasında faydalı bir yöntem olabileceği belirlenmiştir. Çimlendirilmiş tane, taneden elde edilen un veya diğer işlenmiş ürünler, çimlendirme ile artan fonksiyonel özellikleri nedeniyle tahılların geleneksel tüketimine daha iyi bir alternatif olabilirler.

Keywords

• Aktaş
• Toplam fenolik madde miktarı
• Antioksidan aktivite
• Tanen
• Çimlendirme
• Ultrases

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