Judul: Optimasi Pembuatan Minuman Fungsional Berbasis Ekstrak Daun Kumis Kucing (Orthosiphon aristatus BI. Miq) pada Skala Pilot Plant
Abstrak: Functional drink based on java tea extract is a complex drink that contains several herbal extracts and spices. The ingredients are java tea, sappan wood, ginger, turmeric, citrus, keffir lime, lemon. Several researches have been done to get the balance benefit through consumer organoleptic-acceptance. The development of further research is production of functional drink on pilot plant scale. Production on the pilot plant scale needs adjustment of formulation and process condition as a critical parameters to get the optimal quality product. Financial analysis is also important to do for giving a project bussiness overview. The research was conducted in two stages. The first stage was determined of critical parameters of functional drink production on pilot plant scale. The second stage was functional drink production with four factor combination that has been attempted as critical parameters: concentration of citrus, keffir lime, lemon, and water temperature that added into the formula. Optimization of formula and process condition were developed using response surface methodology (RSM) with Design Expert® 7 software. The measured responses are color (L and Hue), organoleptic (color, taste, aroma, and overall), and phytochemical (antioxidant activity and total phenol). Antihiperglicemic activity (inhibition α-glucosidase) was measured at verification stage. Optimum formula obtained was x% concentration of citrus, keffir lime y%, z% lemon juice and water temperature was added at D0C as optimum process condition. The verification results showed the total value of total phenol at 841.1 ppm GAE and antioxidant activity at 709 ppm AEAC. Organoleptic acceptability (scale 7) were color between slightly like and like (5.3), aroma between slightly like and like (5.1), taste between fair and slightly like (4.9), and overall between slightly like and like (5.3). Objective-color analysis showed L 55.31 and Hue 85.81 (yellow red). The antihyperglicemic activity (inhibition α-glucosidase) was at 77.75%. Equality of product characteristic would be obtained if extraction condition, formula and process condition were similar with this research Financial analysis of functional drink stated that the project was feasible to run. Feasibility of this project were net present value Rp. 203 565 151, internal rate ratio 20%, net benefit/cost 1.49%, payback periode for 2.46 years and break even point 81 476 unit.
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Judul: Optimasi Formula  Minuman Fungsional Berbasis Kumis Kucing Menggunakan Ekstrak Hasil  Sterilisasi Non-Termal Teknologi Membran
Abstrak: Minuman fungsional berbasis kumis kucing sudah dikembangkan sejak 2007, namun dalam perjalannya produk ini menghadapi permasalahan terkait tingginya cemaran mikroba, sehingga pengolahannya bergantung pada proses termal dan penggunaan BTP untuk menjaga umur simpan. Penelitian ini bertujuan mengoptimasi formula baru menggunakan ekstrak yang telah melalui membran mikrofiltrasi menggunakan metode D-optimal mixture design pada Response Surface Methodology (RSM) dengan mempertimbangkan sensori hedonik dan aktivitas antioksidannya. Sebanyak 19 rancangan formula dihasilkan oleh software Design Expert 13.0Ⓡ sebagai data keluaran dari data masukan berupa, nilai batas bawah-atas dari ekstrak kumis kucing (EKK: a-d mL), ekstrak kayu secang (EKS: b-e mL), dan ekstrak jahe gajah (EJG: c-f mL). Hasil penelitian menunjukkan formula optimum memiliki nilai desirability sebesar 0,839 (83,9%). Komposisi formula optimum terdiri atas x mL EKK, y mL EKS, dan z mL EJG. Formula optimum tersebut memperoleh nilai aktivitas antioksidan sebesar 352,59±0,42 µM TE/mL, nilai ALT sebesar 1,7 × 101 CFU/mL, dan skor uji hedonik rating untuk atribut aroma (6,5±1,3), warna (6,7±1,3); rasa (7,0±1,1); dan overall (6,8±1,1). Formula optimum memperbaiki penerimaan sensori dan mempertahankan mutu mikrobiologis, walau sedikit menurunkan aktivitas antioksidan., A functional drink based on Java Tea has been in development since 2007, but along the way, this product has faced problems related to high levels of microorganism, so its processing relies on thermal processes and the use of food additives (FA) to maintain shelf life. This research aims to optimize a new formula using extracts that have passed through microfiltration using the D-optimal mixture design in Response Surface Methodology (RSM) by considering the hedonic sensory and antioxidant activity. A total of 19 formula designs were produced by Design Expert 13.0Ⓡ software as output data from input data in the form of lower-upper limit values of java tea extract (EKK: a-d mL), sappan wood extract (EKS: b-e mL), and ginger extract (EJG: c-f mL). The results of the study showed that the optimum formula has a desirability value of 0,839 (83,9%). The optimum formula composition consists of x mL EKK, y mL EKS, and z mL EJG. The optimum formula obtained values of antioxidant activity value at 352,59±0,42 µM TE/mL, ALT value at 1,7 × 101 CFU/mL, and hedonic rating test scores for aroma (6,5±1,3), color (6,7±1,3); taste (7,0±1,1), and overall (6,8±1,1). The optimum formula improves sensory acceptance and maintains microbiological quality, despite a slight reduction in antioxidant activity.
Keyword: Optimasi formula, Response Surface Methodology (RSM), Design expert, Minuman Fungsional Berbasis Kumis Kucing, Antioksidan DPPH, Rating hedonik, Ranking hedonik, Membran mikrofiltrasi, Mikrofiltrasi

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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