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Perubahan Komposisi Kimiawi Produk Yogurt dengan Penambahan Kalsium Karbonat pada Kultur Starter Campuran Safari, Agus; Ghina, Sarah Fahma; Djajasoepena, Sadiah; ', O. Suprijana; Indrawati, Ida; Rachman, Saadah D.; Kamara, Dian S.; Ishmayana, Safri
Jurnal Natur Indonesia Vol 17, No 1 (2016)
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (488.46 KB) | DOI: 10.31258/jnat.17.1.5-12

Abstract

Mixed lactic acid bacteria culture is commonly used in yogurt production. In the present study, two lactic acid bacteria (Lactobacillus bulgaricus and Streptococcus thermophillus) was used as starter culture. Calcium carbonate was added to the starter culture to increase the quality of mixed starter culture of L. bulgaricus and S. thermophillus with ratio of 4:1. The present study was directed to investigate the chemical composition of mixed starter culture with and without calcium carbonat addition. Furthermore, the effect of each starter culture on yogurt product chemical composition was also examined. The pH, lactose, soluble protein and acid content was determined as chemical composition parameters. For starter culture without calcium carbonate addition, the yogurt has pH, lactose, soluble protein and acid content of 4.18–4.39, 4.18–4.39% w/v, 2.88–4.36% w/v and 0.82–0.99% w/v, respectively. While for starter culture with calcium carbonate addition, the yogurt product has pH, lactose, soluble protein and acid content of 4.26–4.37, 1.47–1.75% b/v, 3.42–4.95% w/v and 0.86–1.11% w/v, respectively. Addition of 0.05% w/v calcium carbonate to mixed starter culture gave effect on lactose consumption, where it still can convert lactose to lactic acid up to 45 days of storage. Furthermore, the yogurt product made with starter culture with calcium carbonate addition has higher soluble protein content compared to yogurt made with starter culture without calcium carbonate addition
Pengaruh Suplementasi Ion Logam Besi Terhadap Kinerja Fermentasi dan Toleransi Sel Ragi Saccharomyces cerevisae terhadap Cekaman Lingkungan Rachman, Saadah D.; Putri, Tysza Ainnunnisa Maulidya; Safari, Agus; Anggraeni, Nenden I.; Fadhlillah, Muhammad; Ishmayana, Safri
Jurnal MIPA Vol 9, No 2 (2020)
Publisher : Sam Ratulangi University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jmuo.9.2.2020.28565

Abstract

Selama proses fermentasi bioetanol, ragi Saccharomyces cerevisiae terpapar berbagai cekaman lingkungan. Ion logam yang berpotensi untuk meningkatkan kinerja fermentasi dan toleransi sel terhadap cekaman ialah ion logam besi II (Fe2+) yang berperan sebagai kofaktor dalam berbagai proses metabolisme. Tujuan dari penelitian ini adalah mempelajari pengaruh suplementasi ion Fe2+ dalam media fermentasi terhadap kinerja fermentasi, serta toleransi sel ragi terhadap cekaman etanol, oksidatif, asam lemah dan tekanan osmotik. Penelitian diawali dengan melakukan fermentasi glukosa menggunakan S. cerevisiae A12 selama 120 jam dengan pengambilan sampel dengan interval waktu 6 jam untuk 24 jam pertama serta 12 jam untuk sisanya. Masing-masing sampel ditentukan nilai OD600nm, persentase sel hidup, jumlah sel hidup, kadar glukosa, kadar etanol. Pada jam ke 24, sel diuji daya tahannya terhadap cekaman. Hasil penelitian menunjukkan bahwa suplementasi ion logam Fe2+ hanya mampu meningkatkan laju produksi etanol, tetapi tidak mempengaruhi parameter lain.During bioethanol fermentation process, Saccharomyces cerevisiae yeast cells are exposed to various environmental stress factors. One of metal ions that have potency for improving fermentation performance and yeast stress tolerance is ferrous ion (Fe2+) that acts as cofactors in various metabolism process. The present study was directed to investigate the effect of ferrous ion supplementation to the fermentation media on fermentation performance, improving yeast stress tolerance against ethanol, oxidative, weak acid and hyperosmotic stresses. The fermentation was conducted by fermenting glucose using S. cerevisiae strain A12 for 120 hours. The sampling was performed every 6 hours during the first 24 hours and 12 hours for the rest of fermentation. The sample was examined for their OD600nm, total cell number, viable cell number, glucose content and ethanol content. At 24 hours the cell was examined for their stress tolerance. The result of the present study indicates that supplementation using ferrous ion improve the rate of ethanol production, but not other parameters.