In Vitro Stability of Phytase from Recombinant Bacteria E. Coli BL21 (DE3) EAS1-AMP

The objective of the research was to inquire the Km, Vm, activity, intracellular phytase stability exposed to pH variation, temperature variation and protease (pepsin and pancreas) in vitro. The phytase was produced from recombinant bacteria E. coli BL21(DE3) EAS1-AMP using 1.5 mM IPTG as inducer. Intracellular enzyme was extracted via freeze shock and centrifugation. Pure enzyme was acquired through NI-NTA agarose column. The enzyme was then tested for Km, Vm, phytase activity and stability against pH, temperature and protease. Treatment levels for stability against protease were P0: without protease, P1: addition of pepsin, P2: addition of pepsin and pancreas, and the data were statistically analyzed using analysis of variance of one-way Completely Randomized Design. Crude intracellular phytase had Vm 6.39 υM/sec, Km 34.82 υM, and 277 units activity. Intracellular phytas was stable at pH 4–6 and 0–550 C. Protease level influenced the activity of intracellular phytase (P<0.05). Intracellular phytase was stable against pepsin but not pancreas. Keywords: Km, Vm, activity, intracellular phytase, pH, temperature, protease

PRODUCTION AND CHARACTERIZATION OF CRUDE INTRACELLULER PHYTASE FROM RECOMBINANT BACTERIA pEAS1AMP

This research was aimed at producing a crude intracellular phytase characterized from recombinant bacteria. The recombinant bacteria (pEAS1AMP) was produced by way of transforming pET-22b(+) +pEAS1 into competent E. coli BL21 and E. coli BL21(DE3) cells. Crude intracellular phytase production was induced using 1,5 mM Isopropyl-β-D-thiogalactopyranosid (IPTG). Recombinant bacteria product and enzyme activity test followed the Sajidan method. E. coli BL21(+)pEAS1 and E. coli BL21 (DE3)(+)pEAS1 recombinant bacteria showed growth after 20 hours and 10 hours of transformation. Phytase activity of E. coli BL21 (DE3)(+)+pEAS1 showed higher than those of E. coli BL21(+)+pEAS1. Crude intracellular phytase of pEAS1AMP recombinant bacteria has an optimum activity at pH 5, 40o C, incubation period of 60 minutes, substrate concentration of 2%, molecular weight (MW) of 47.3 kDa, Km = 15.91 υM and Vm = 2.41 υM/second. Mg2+ acts as a cofactor but Fe3+ (10-4 M) acts as an inhibitor. Keywords: bacteria recombinant pEAS1AMP, competent cells, crude intracellular phytas

Manfaat Bromelin dari Ekstrak Buah Nanas (Ananas comosus L. Merr) dan Waktu Pemasakan untuk Meningkatkan Kualitas Daging Itik Afkir

Penelitian bertujuan untuk mengetahui pengaruh aras penambahan ekstrak buah nanas (Ananas comosus L. Merr) yang mengandung bromelin, aras waktu pemasakan dan interaksi antara kedua faktor terhadap keempukan, kekuatan tarik, pH, daya ikat air (DIA) dan susut masak daging itik afkir. Itik yang digunakan adalah 18 itik Mojosari umur 84 minggu. Sampel untuk uji keempukan dan kekuatan tarik menggunakan daging paha bawah, uji pH, DIA dan susut masak menggunakan daging paha bagian atas. Rancangan penelitian menggunakan Rancangan Acak Lengkap (RAL) Pola Faktorial 4 × 3, dengan faktor pertama penambahan ekstrak buah nanas (0, 5, 10, 15%) dan faktor kedua waktu pemasakan (0, 30, 60 menit). Terdapat interaksi antara penambahan ekstrak buah nanas dan waktu pemasakan (P<0,01) pada pH, DIA, susut masak dan (P<0,05) pada kekuatan tarik. Penambahan ekstrak buah nanas dan waktu pemasakan dapat meningkatkan keempukan, pH, daya ikat air dan menurunkan susut masak daging itik. Penambahan ekstrak buah nanas 15% dan waktu pemasakan 60 menit menghasilkan kualitas daging itik yang terbaik. Kata kunci : ekstrak buah nanas, pemasakan, daging, itik afkir, kualitas fisi

Evaluasi Kualitas Organoleptik Mayonnaise Berbahan Dasar Kuning Telur yang Mendapatkan Suplementasi Tepung Purslane (Portulaca oleracea)

The aim of this research was to evaluate sensory quality of mayonnaise made with egg yolks produced from laying hens fed diets supplemented with purslane meal. The experimental design was a one way classification with five mayonnaise treatments. The treatments included mayonnaise with egg yolks supplemented with 0% (P0), 2% (P1), 4% (P2), 6% (P3), and 8% (P4) purslane meal. This study used 30 semi-trained panelists to evaluate sensory quality of mayonnaise using a 9-point hedonic scale. Data was analysed using the analysis of variance and if there was any significant difference among treatments, then the analysis was continued using Tukey’s test. The results showed that the use of egg yolks from laying hens fed diets supplemented with purslane meal up to a level of 8% did not significantly change color, texture, creamy, aroma, taste, taste and overall acceptance of mayonnaise. The average score of perception of sensory attributes was between 5 (neither like nor dislike) and 6 (slightly like). It can be concluded that mayonnaise made with egg yolks produced from brown laying hens fed diets supplemented with purslane meal up to a level of 8% did not negatively affect the sensory quality of mayonnaise