Optimization of ultrasonic‐assisted extraction conditions for bioactive components from coffee leaves using the Taguchi design and response surface methodology

Abstract

Coffee leaves contain various bioactive compounds that are beneficial for human health. However, there are very limited researches related to the extraction of the bioactive phytochemicals from coffee leaves. In the present study, the extraction conditions for bioactive components from coffee leaves were optimized using Taguchi design and response surface methodology (RSM). Taguchi design was used to screen significant factors that affected the yield of phytochemicals including trigonelline, caffeine, chlorogenic acids, mangiferin, and rutin, total phenolic content (TPC) and antioxidant activity. Sequentially, a Box‐Behnken design (BBD) was used to optimize the extraction conditions. Three factors including Liquid‐to‐solid (L:S) ratio, ethanol concentration, and extraction temperature that significantly affected most of the phytochemical yields and antioxidant activity were selected from the six variables using Taguchi design. The optimal extraction conditions obtained from RSM were 30.3:1 L:S ratio, 54.5% ethanol, and 80 °C when simultaneously considered four responses, including TPC, the yields of mangiferin and 5‐CQA and DPPH scavenging capacity. Under the optimal conditions, the experimental results for the above four responses were 62.1 mg gallic acid/g, 4.1 mg/g, 11.4 mg/g, and 356.9 µmol Trolox/g, respectively, which were close to the predicted values. About 97% of phytochemicals can be extracted in the first two times of extraction. In conclusion, the combination of Taguchi design and response surface methodology can be successfully used to screen and optimize the significant factors that affected the bioactive components extracted from coffee leaves. Practical Application Coffee leaves, the byproducts of coffee plants, are considered no‐ or low‐value although it has a long history for using them as tea‐like beverage and ethnomedicine by locals in the coffee plant growing countries. Bioactive components extracted from coffee leaves can be used as ingredients in functional beverages, functional food, and natural health products. These applications will add values to coffee leaves as well as increase the incomes of coffee farmers and workers.

Tea processing steps affect chemical compositions, enzyme activities, and antioxidant and anti‐inflammatory activities of coffee leaves

“…The phenolic content was determined by Folin–Ciocalteu methods described by X. Chen et al. (2020). Briefly, 20 μl of appropriately diluted free or bound phenolics extracts or 0.1 mg/ml gallic acid standard were reacted with 100 μl, 10 times diluted Folin–Ciocalteu reagent at room temperature for 1 min, followed by incubation with 80 μl, 75 mg/ml Na 2 CO 3 for 30 min.…”

Updating thestatus quoon the extraction of bioactive compounds in agro-products using a two-pot multivariate design. A comprehensive review

“…Although many factors influence the extraction process, some do not significantly affect bioactive compounds’ extraction. 6,9,10,16 The essential components and how they interact with all other potential factors are identified using screening designs. These study qualitative, quantitative, and interacting parameters simultaneously.…”

“…Full-FD and fractional-FD are the types into which factorial designs are typically divided. 6,9,10,16…”

“…Fractional factorial design (fractional-FD), two-level full factorial (Full-FD), Taguchi, and Plackett–Burman design (PBD) are some of the methodologies used. 6,16,18,23,24…”

A metabolomic platform to identify and quantify polyphenols in coffee and related species using liquid chromatography mass spectrometry

“…Indeed, ultrasonication has been widely used to reach higher yields of natural compounds (Annegowda et al, 2010;Masson et al, 2010;Hasan et al, 2017). For instance, ultrasonic-assisted extraction has been used in coffee leaves to improve the extraction of caffeine, trigonelline, rutin, chlorogenic acids, and mangiferin (Chen et al, 2020b). Furthermore, steroidal alkaloids have been successfully recovered from potato peel using ultrasound assisted extraction, obtaining at least 1.5 times more compounds in comparison with other extraction technique (Hossain et al, 2014).…”