The objective of this study was to ascertain the impact of ultrasound application on the probiotic characteristics and antioxidant activity of yeasts. In this context, the pH changes, probiotic properties and antioxidant activities of K. marxianus (Km), S. boulardii (Sb) and S. cerevisiae (Sc) were determined by ultrasound application at different durations (5, 15, 30 and 60 minutes at 24 kHz). The lowest pH values were determined for cultures of Km (ultrasound non-applied K. marxianus), Sb-30 (30 min. ultrasound applied S. boulardii) and Sc-5 (5 min. ultrasound applied S. cerevisiae) as 4.48, 5.15 and 5.26, respectively. The hydrophobicity values of the yeast strains varied between 6% and 24%, increased with ultrasound application. Although S. boulardii had the highest tolerance to low pH and bile salts, the resistance of all yeast to low pH and bile salts decreased with ultrasound application. K. marxianus had the least survival under in vitro conditions, but ultrasound application increased survival of K. marxianus strains and slightly affected the survival rate of S. boulardii and S. cerevisiae. Increasing of duration time of ultrasound application resulted higher antioxidant activity and so the highest antioxidant activity was determined for Sb-60. Finally, ultrasound application could be used for the development of hydrophobicity and antioxidant properties of yeast cultures.

Bu çalışma, acı baklanın (Lupinus albus L.) acılığı giderme sürecinde bir ön işlem yöntemi olarak ultrasonun etkinliğini araştırarak, genel kalitesini ve besin profilini iyileştirmeyi amaçlamaktadır. Acı bakla tohumları protein ve diğer temel besin maddeleri bakımından bol miktarda bulunur, ancak başta acı bakla ve lupinidin olmak üzere acı alkaloidler içerirler ve bu da bunların gıda ve yem olarak kullanılmasında zorluklar yaratır. Geleneksel acılık giderme yöntemleri, zaman alıcı olan ve besin kayıplarına yol açabilen suya batırmayı içerir. Ultrason, besin bütünlüğünden ödün vermeden acılık giderme sürecini hızlandırma kabiliyeti nedeniyle umut verici bir alternatif olarak ortaya çıkıyor. Bu araştırmada, acılık giderme verimliliğini optimize etmek için acı bakla tohumlarına çeşitli koşullar altında ultrason ön işlemi uygulandı. Ultrason gücü, işlem sıcaklığı ve süresi gibi parametreler, alkaloitlerin uzaklaştırılması ve besin içeriğinin korunması üzerindeki etkilerini belirlemek için sistematik olarak değerlendirildi. Ön işleme tabi tutulmuş Lupin numuneleri daha sonra alkaloit konsantrasyonları, protein içeriği ve diğer besin özelliklerindeki değişiklikler açısından analiz edildi. Uygulanan ultrason destekli ekstraksiyon yöntemi yeni bir bakış açısı getirmiş ve ısıtma işlemi ultrasonla uyarlanarak acılık giderme işlemi daha kısa sürede gerçekleştirilmiştir. Ön sonuçlar, acı bakla tohumlarındaki acılık seviyelerini ve alkaloid konsantrasyonlarını azaltmada ultrason ön işleminin etkinliğini göstermektedir. Üstelik süreç, Lupin'de bulunan temel besin maddelerini korur ve böylece insan tüketimi ve hayvan yemi için değerli bir protein ve diğer besin kaynağı olma potansiyelini artırır. Bu çalışma Lupin için sürdürülebilir ve verimli ön arıtma yöntemlerinin geliştirilmesine katkıda bulunarak gıda, yem ve çeşitli endüstriyel uygulamalarda daha geniş kullanımının yollarını açıyor.

The aim of this study was to obtain an extract rich in bioactive components from yellow onion peels, which are generally considered waste material. Accordingly, a three-factor three-level Taguchi (L9) experimental design with three factors, namely ethanol concentration (A; 50%, 75%, 100%), extraction temperature (B; 30, 40, 50 °C), and sonication time (C; 10, 20, 30 min) was used to optimize the ultrasound-assisted extraction process of onion peel powders. Through Taguchi optimization, the optimum extraction conditions were determined as A2B3C2 to obtain the extract with the highest total phenolic matter (TPM) content and antioxidant activity (DPPH (%)). In addition, the extract produced under A2B1C2 conditions was found to be the richest in total monomeric anthocyanin (TMA) content with the highest level of color pigments. In order to determine the overall optimization conditions and to reduce the three-response optimization process to a single response, the simple sum weighting (SAW) method was used as a multi-criteria decision-making method. As a result of the optimization, it was concluded that an extract rich in bioactive components with optimal TPM and TMA contents and DPPH (%) value could be obtained as a result of sonication at 30 °C for 20 min to onion peel powders mixed with a solvent containing 75% ethanol (A2B1C2). The extraction conditions of bioactive components from yellow onion peels were successfully optimized by the Taguchi-SAW hybrid optimization method.

The aim of this study was to obtain an extract rich in bioactive components from yellow onion peels, which are generally considered waste material. Accordingly, a three-factor three-level Taguchi (L9) experimental design with three factors, namely ethanol concentration (A; 50%, 75%, 100%), extraction temperature (B; 30, 40, 50 °C), and sonication time (C; 10, 20, 30 min) was used to optimize the ultrasound-assisted extraction process of onion peel powders. Through Taguchi optimization, the optimum extraction conditions were determined as A2B3C2 to obtain the extract with the highest total phenolic matter (TPM) content and antioxidant activity (DPPH (%)). In addition, the extract produced under A2B1C2 conditions was found to be the richest in total monomeric anthocyanin (TMA) content with the highest level of color pigments. In order to determine the overall optimization conditions and to reduce the three-response optimization process to a single response, the simple sum weighting (SAW) method was used as a multi-criteria decision-making method. As a result of the optimization, it was concluded that an extract rich in bioactive components with optimal TPM and TMA contents and DPPH (%) value could be obtained as a result of sonication at 30 °C for 20 min to onion peel powders mixed with a solvent containing 75% ethanol (A2B1C2). The extraction conditions of bioactive components from yellow onion peels were successfully optimized by the Taguchi-SAW hybrid optimization method.

The use of bioactive compounds has been maintaining its significance from nutritional aspects. Due to the increasing demand for them in potential markets, researchers struggle to create new sources and improve their methods. Plant materials possess plenty and a diverse range of these compounds. However, their availability strongly depends on the extraction techniques in addition to the sampling methods and the applicability of the method to the specific parts of the plant. Thus, it is crucial to develop a common, precise way which will enable to extract all the active components regardless of their origin and their location in the plant material. Besides, the new method ought to have the highest economic value in comparison to the present applications which means that the efficiency of the extraction should be acceptable on industrial scale as well. Even though numerous methods have been improved so far, it seems to be unlikely to achieve a standardized solution with high valorization for the extraction of bioactive compounds from plants until now. This review aims to discuss the novel extraction methods in addition to the conventional techniques focusing on the critical parameters such as the cost, time, yield, feasibility and eco-friendliness of the process.