Pengaruh Lama Fermentasi Yoghurt Sinbiotik Ubi Jalar Ungu (Ipomea batatas L) dengan Kultur Starter Probiotik terhadap Mutu Produk dan Aktivitas Antioksidan

Effect Of The Fermentation Time Of Purple Sweet Potato (Ipomea batatas L) Synbiotic Yoghurt With Probiotic Starter On Product Quality and Antioxidant Activity

Ubi jalar ungu (Ipomea batatas L) memiliki potensi sebagai media fermentasi karena memiliki kandungan karbohidrat yang tinggi sekitar 20,1%. Kombinasi ekstrak ubi jalar ungu, susu skim, dan starter probiotik diharapkan menjadi yoghurt sinbiotik yang dapat membantu sistem pencernaan. Penelitian ini bertujuan untuk mengetahui pengaruh lama fermentasi yoghurt sinbiotik ubi jalar ungu dengan kultur starter probiotik terhadap mutu produk dan aktivitas antioksidan. Mutu yang diamati adalah mutu kimia, mutu mikrobiologi, mutu organoleptik dengan variasi waktu fermentasi 0, 4, 8, dan 12 jam. Hasil penelitian menunujukkan bahwa ada pengaruh lama fermentasi yoghurt sinbiotik ubi jalar ungu dengan kultur starter probiotik terhadap mutu yoghurt. Pada variasi waktu fermentasi 0 jam tidak memenuhi standar mutu kimia pH dengan nilai 5,16 tetapi, memenuhi standar mutu kimia TAT dengan nilai 0,513%, sedangkan variasi lama fermentasi 4-12 jam memenuhi standar mutu pH dengan nilai 3,88-4,33 dan TAT dengan nilai 1,268-1,967%. Pada mutu mikrobiologi terdapat kenaikan total BAL yitu 46,2×107 - 90,61×107. Mutu organoleptik warna, rasa dan aroma terbaik didapat pada variasi fermentasi 8 jam, sedangkan mutu organoleptik tekstur terbaik didapat pada variasi fermentasi 12 jam. Aktivitas antioksidan terbaik diperoleh pada waktu fermentasi 12 jam dengan nilai IC50 62,727 ppm.

Purple sweet potato (Ipomea batatas L) has the potential as a fermentation medium because it has a high carbohydrate content of around 20.1%. The combination of purple sweet potato extract, skimmed milk, and probiotic starter is expected to be a synbiotic yogurt that can help the digestive system. This study aims to determine the effect fermentation time of purple sweet potato synbiotic yogurt with probiotic starter culture on the quality of yogurt products. The observed quality was chemical quality, microbiological quality, organoleptic quality with variations in fermentation time of 0, 4, 8, and 12 hours.  The results of the study showed that there was an effect of the long fermentation of purple sweet potato synbiotic yogurt with probiotic starter culture on the quality of yogurt. In the variation of 0-hour fermentation time, it did not meet the pH chemical quality standard with a value of 5.16 but met the TAT chemical quality standard with a value of 0.513%, while the variation of fermentation time of 4-12 hours met the pH quality standard with a value of 3.88-4.33 and TAT with a value of 1.268-1.967%. In the quality of microbiology, there was a total increase in BAL, which was 46.2×10⁷ - 90.61×10⁷. The best organoleptic quality of color, taste and aroma was obtained in the 8-hour fermentation variation, while the best texture organoleptic quality was obtained in the 12 hour fermentation variation. The best antioxidant activity was obtained at 12 hours of fermentation time with an IC₅₀ value of 62.727 ppm.

Keywords: Synbiotic yogurt, purple sweet potato, probiotic starter, quality, antioxidant activity