Pengaruh Lama Fermentasi Minuman Sari Bengkuang (Pachyrhizus erosus) Dengan Kultur Starter Lactobacillus plantarum B1765 Terhadap Karakteristik Produk dan Aktivitas Penghambatan Alfa-Glukosidase

Effect of Fermentation Time of Jicama Juice (Pachyrhizus erosus) With Lactobacillus plantarum B1765 as Starter Culture on Product Quality and Alpha-Glucosidase Inhibitor Activity

Aktivitas penghambatan enzim α-glukosidase adalah kemampuan enzim untuk menghambat proses hidrolisis karbohidrat kompleks menjadi gula sederhana di usus sehingga dapat mempertahankan absorbsi gula dalam darah dalam batas normal terutama bagi penderita diabetes. Penelitian ini mengkaji pengaruh lama fermentasi minuman sari bengkuang dengan kultur starter Lactobacillus plantarum B1765 terhadap karakteristik produk dan aktivitas penghambatan enzim α-glukosidase. Sari bengkuang diinokulasi dengan L. plantarum B1765 5% (v/v) dan difermentasi selama 2, 12, 24, dan 36 jam pada suhu 37 ⁰C, kemudian diuji karakteristik kimia (pH, Total Asam Tertitrasi, total fenolik, penghambatan enzim α-glukosidase) dan karakteristik mikrobiologi (total Bakteri Asam Laktat). Pengujian Total Asam Tertitrasi (TAT) dilakukan dengan metode titrasi asam basa, pertumbuhan total BAL dilakukan dengan metode Total Plate Count (TPC), total fenolik diukur menggunakan metode Folin-Ciocalteu, dan pengujian aktivitas penghambatan enzim α-glukosidase diukur menggunakan subsrat p-nitrofenil-α-D-glukopiranosida (pNPG) dan enzim α-glukosidase dari Saccharomyces cerevisiae. Hasil penelitian menunjukkan bahwa lama fermentasi mempengaruhi peningkatan total BAL, TAT, total fenolik, dan penurunan pH, penghambatan enzim α-glukosidase. Lama fermentasi minuman sari bengkuang hingga 36 jam fermentasi menunjukkan peningkatan pertumbuhan BAL mencapai 2,95 x 10⁸ CFU/mL diikuti dengan peningkatan TAT sebesar 0,223% dan peningkatan total fenolik mencapai 40,26 mg GAE/g. Nilai pH mengalami penurunan hingga sebesar 3,28 diikuti dengan penurunan penghambatan enzim α-glukosidase dengan nilai IC₅₀ 6,69 μg/mL. Aktivitas penghambatan ini dikaterogikan sangat aktif sebagai antidiabetes. Oleh karena itu, minuman sari bengkuang yang difermentasi dengan kultur starter L. plantarum B1765 berpotensi untuk digunakan sebagai penghambat enzim α-glukosidase bagi penderita diabetes.

The inhibitory activity of α-glucosidase enzyme can reduce the rate of glucose uptake by delaying the digestion of carbohidrates. This research studied the effect of the fermentation time of jicama juice with Lactobacillus plantarum B1765 as a starter culture on product quality and a-glucosidase inhibitor activity. The jicama juice was inoculated with L. plantarum B1765 5% (v/v) and fermented for 2, 12, 24, and 36 hours at 37 ⁰C, then determined the chemical characteristics (pH, Total Titratable Acid (TTA), total phenolic, and α-glucosidase enzyme inhibitory) and microbiological characteristics ia Total Lactic Acid Bacteria (LAB). TTA was measured using acid-base titration, the total LAB count was measured using the Total Plate Count (TPC), total phenolic was measured using Folin-Ciocealteu method, and α-glucosidase enzyme inhibitory activity was measured using p-nitrophenyl-α-D-glucopyranoside (pNPG) subsrate and α-glucosidase enzyme from Saccharomyces cerevisiae. The result showed that the length of fermentation affected the increase in total LAB, TAT, total phenolic, and decreased pH, α-glucosidase enzyme inhibitory. The length of fermentation of jicama juice up to 36 hours of fermentation showed an increase in LAB growth reaching 2.95 x 10⁸ CFU/mL followed by an increase in TAT of 0.223% and total phenolic to 40.26 mg GAE/g. The decrease in pH to 3.28 followed by a decrease inhibition of α-glucosidase enzyme was obtained with an IC₅₀ value of 6.69 μg/mL until 36 hours of fermentation. Therefore, jicama juice fermented with L. plantarum B1765 starter culture has the potential to inhibit α-glucosidase enzyme for diabetics.