VARIASI RASIO SARI BIT MERAH (Beta vulgaris L.), SUSU SKIM, DAN KULTUR STARTER TERHADAP KARAKTERISTIK YOGHURT SARI BIT MERAH [THE VARIATION OF RED BEET (Beta vulgaris L.) JUICE RATIO, SKIM MILK, AND STARTER CULTURE TO RED BEET JUICE YOGURT] - Eveline Eveline; Ayu Anisa Nawangsih (FaST : Jurnal Sains dan Teknologi, 2019)
Red beet (Beta vulgaris L.) is one of tuber plants that are usually consumed as juice and salad ingredients. Its bioactive and functional nutrition compund such as antioxidant, phenolic, and flavonoids made red beet application needs to be developed. This study aims to produce the best red beet yoghurt based on variations in beet juice ratio and the concentration of skim milk and starter. Red beet extract was made in 1:3, 1:4, and 1:5 (w/v) ratio. 1:3 ratio gave the best analysis results based on its antioxidant activity IC50 of 93660.00 ppm, phenolic compound of 281.03 mg GAE/l, and flavonoids compound of 163.06 mg QE/l. This ratio was used in the next step to determine the skim milk concentration (6, 8, and 10%) and Lactobacillus bulgaricus : Streptococcus thermophilus 1:1 starter culture concentration (3, 5, and 7% [w/v]) in yogurt making process. pH, total titratable acidity (TAT), total lactic acid bacteria (LAB), viscosity, and coliform test was used as parameters to determine the 6% skim milk and 7% starter culture as the best result. Red beet yogurt with 4.12 pH, TTA of 0.78%, total LAB of 2.8 x 1010 CFU/ml, viscosity of 15688.00 cps, and no coliform; was then analyzed its antioxidant activity (IC50), total flavonoids, total phenolic, proximate, toxicity, and hedonic test. Sequentially, the product’s results were 296505.00 ppm (the result increased 316.58% after fermentation); 85.18 mg QE/ml; 149.24 mg GAE/l; 87.14% water, 0.82% ash content, 0.18% fat, 3.21% protein, 8.66% total carbohydrate (by difference); LC50 747.56 ppm (low toxicity); and it was still acceptable to consumers (hedonic score 4.94 of 7). All of the analysis results were refers to national and international standards.  ABSTRAKBit merah (Beta vulgaris L.) merupakan salah satu jenis umbi-umbian yang biasa dikonsumsi sebagai jus dan bahan pembuatan salad. Kandungan senyawa bioaktif dan nutrisi fungsional seperti antioksidan, fenolik, dan flavonoid membuat pemanfaatan bit merah perlu dikembangkan. Penelitian ini bertujuan untuk menghasilkan yoghurt bit merah terbaik berdasarkan variasi rasio sari bit serta konsentrasi susu skim dan starter. Awalnya, sari bit merah dibuat dengan rasio 1:3, 1:4, dan 1:5 (b/v). Rasio 1:3 memberikan hasil analisis terbaik berdasarkan aktivitas antioksidan IC50 93660,00 ppm, fenolik 281,03 mg GAE/l, dan flavonoid 163,06 mg QE/l. Rasio ini digunakan pada tahap selanjutnya untuk penentuan konsentrasi susu skim (6, 8, dan 10%) dan konsentrasi kultur starter Lactobacillus bulgaricus : Streptococcus thermophillus 1:1 (3, 5, dan 7% [b/v]) dalam pembuatan yoghurt. Analisis pH, Total Asam Tertitrasi (TAT), total Bakteri Asam Laktat (BAL), viskositas, dan uji koliform menjadi parameter acuan untuk menentukan susu skim 6% dan kultur starter 7% sebagai konsentrasi yang memberikan hasil analisis terbaik. Yoghurt bit merah dengan pH 4,12, TAT 0,78%, total BAL 2,8 x 1010 cfu/ml, viskositas 1568,00 cps, dan tanpa pertumbuhan koliform selanjutnya dianalisis aktivitas antioksidan (IC50), total flavonoid, total fenolik, proksimat, toksisitas, dan uji hedonik. Secara berurutan hasil analisis produk 296505,00 ppm (meningkat 316,58.% setelah fermentasi); 85,18 mg QE/ml; 149,24 mg GAE/l; air 87,14%, abu 0,82%, lemak 0,18%, protein 3,21%, karbohidrat (by difference)  8,66%; LC50 747,56 ppm (toksik rendah); dan masih dapat diterima konsumen (hedonik 4,94 dari skala 7). Seluruh penentuan hasil analisis mengacu pada standar nasional dan internasional.