PEMANFAATAN EKSTRAK DAUN JAMBU BIJI (Psidium guajava) DAN SERBUK DAUN STEVIA (Stevia rebaudiana) DALAM PEMBUATAN MINUMAN FUNGSIONAL [Utilization of Guava (Psidium guajava) Leaves Extract and Stevia (Stevia rebaudiana) Leaves Powder in The Preparation of Functional Drink] - Stella, Stella; Siregar, Tagor Marsillam (FaST - Jurnal Sains dan Teknologi (Journal of Science and Technology), 2020)
Functional drink from guava (Psidium guajava Linn.) leaves are beneficial for human health, as a medicine for diarrhea, cough, antidiabetic, and antioxidants. Guava leaf in Indonesia has many varieties. This research uses guava leaves ”˜Kristal’, ”˜Sukun Merah’, and ”˜Australia’ varieties. The purpose of this study was the utilization of guava leaves extract in functional drinks with the addition of stevia leaves as a sweetener. This research was divided into 2 stages. Preliminary stage was carried out to determine guava leaves extract that will be used in functional beverages based on Î±-glucosidase inhibition activity and antioxidant activity. The main research was carried out by making functional drinks using different concentration of guava leaves extract (0.15; 0.175; and 0.2%) and different concentration of stevia leaves powder (0.025; 0.05; and 0.075%). All functional drink formulations were tested for sensory test (scoring and hedonic), pH, total soluble solids, and color tests. The functional drink was selected based on the results of the hedonic tests and analyzed for total phenolic, total flavonoid, antioxidant activity, and Î±-glucosidase inhibition activity. Selected guava leaves extract was ”˜Sukun Merah’ with Î±-glucosidase inhibition activity (IC50) of 38.18 ppm and antioxidant activity (IC50) of 21.69 ppm. The concentration of guava leaves extract and stevia leaves powder significantly affected the pH and °Hue of functional drinks. The chosen functional drink formulation is the one with 0.175% guava leaves extract and 0.075% stevia leaves powder. Selected functional drink have a total phenolic of 5.42 mg GAE/mL, total flavonoid of 0.07 mg QE/mL, antioxidant activity (IC50) of 3041.04 ppm, and Î±-glucosidase inhibition activity of 17066.65 ppm.Abstrak Daun jambu biji (Psidium guajava Linn.) telah dimanfaatkan bagi kesehatan tubuh manusia, seperti sebagai obat diare, batuk, antidiabetes, dan antioksidan. Di Indonesia tanaman jambu biji  memiliki berbagai varietas. Penelitian ini menggunakan daun jambu biji varietas Kristal, Sukun Merah, dan Australia. Tujuan penelitian ini adalah pemanfaatan ekstrak daun jambu biji dalam minuman fungsional dengan penambahan daun stevia sebagai pemanis. Penelitian ini dibagi menjadi 2 tahap. Penelitian pendahuluan dilakukan untuk menentukan varietas daun jambu biji yang akan digunakan pada pembuatan minuman fungsional berdasarkan aktivitas inhibisi Î±-glukosidase dan aktivitas antioksidan. Pada Penelitian utama dilakukan pembuatan minuman fungsional dengan perlakuan konsentrasi ekstrak daun jambu biji (0,15; 0,175; dan 0,2%) serta konsentrasi serbuk daun stevia (0,025; 0,05; 0,075%). Seluruh formulasi minuman fungsional dianalisis meliputi uji sensori (scoring dan hedonik), uji pH, uji total padatan terlarut, dan uji warna. Minuman fungsional terpilih ditentukan berdasarkan  parameter hedonik, total fenolik, total flavonoid, aktivitas antioksidan, dan aktivitas inhibisi Î±-glukosidase. Ekstrak daun jambu biji terpilih yaitu varietas Sukun Merah dengan aktivitas inhibisi Î±-glukosidase (IC50) sebesar 38,18 ppm dan aktivitas antioksidan (IC50) sebesar 21,69 ppm. Konsentrasi ekstrak daun jambu biji dan serbuk daun stevia berpengaruh signifikan terhadap pH dan °Hue minuman fungsional. Formulasi minuman fungsional terpilih yaitu konsentrasi ekstrak daun jambu biji sebesar 0,175% dan konsentrasi serbuk daun stevia sebesar 0,075%. Minuman fungsional terpilih memiliki total fenolik sebesar 5,42 mg GAE/mL, total flavonoid sebesar 0,07 mg QE/mL, aktivitas antioksidan (IC50) sebesar 3.041,04 ppm, dan aktivitas inhibisi Î±-glukosidase (IC50) sebesar 17.066,65 ppm. Minuman terpilih berpotensi menjadi minuman fungsional dengan manfaat sebagai antioksidan dan antidiabetes.