Judul: Development of a Process for Producing Red Tea Syrup Using Vacuum Evaporator EVAP-50 Owner Food Machinery
Abstrak: Tea is the most popular beverage next to water. Preparation of tea from dried tea leaves require many steps and is time-consuming. The goal of this research is to make a convenient way to prepare tea syrup with vacuum evaporation process. In the present study the effect of vacuum evaporating condition on the properties of tea syrup and the most suitable condition for making tea syrup were investigated with rating hedonic approach. Dried red tea leaves (Camellia sinenesis var. assamica) were supplied from Boon Rawd Farm Co., Ltd in Chiang Rai. The samples were ground using hammer mill. Samples (1720 grams) were extracted with 43 L boiled water, infused for 5 minutes with stirring. Solids were filtered. Sucrose was added to tea extract until TSS of 26 oBrix was reached. These initial concentration was evaporated until 68 oBrix under vacuum with various pressures (-500 mmHg and -400 mmHg) and temperatures (70 oC and 60 oC). Sensory characteristics were evaluated for tea syrup and tea drink. There was difference in value of sensory characteristics of tea syrup and tea drink of different treatment. Based on panelists, the highest score of both tea syrup and tea drink were at treatment of 70 oC/-400 mmHg/28 h 30’. The shortest time of processing was at treatment of 70 oC/-500 mmHg/8 h 35’. Meanwhile, the treatment resulted in the highest total polyphenol was at treatment of 60 oC/-500 mmHg/35 h 8’. Keeping tea syrup in room temperature for around 3 weeks that had once been opened, the growth of molds was observed. Hence, the addition of preservative is suggested.
Keyword: vacuum evaporation, tea drink, tea syrup, sensory analysis, formulation

Judul: Pembuatan Minuman Teh Hijau dalam Botol dengan Penambahan Ekstrak Klorofil Daun Suji (Pleomele angustifolia N. E. Brown) dan Evaluasi Mutunya selama Penyimpanan
Abstrak: Green tea is the most famous health drink in the world. Polyphenolic compounds contained in green tea have many usages, so that also with suji leaf (Pleomele angustifolia). Production of green tea drink with the addition of chlorophyll extract of suji leaf was increased its antioxidant content. The objective of this research was established the formulation of green tea drink product which combined with chlorophyll extracts from suji leaf, the long time of heating process, and the shelf life of drink product. The storage evaluate had been performed by ASLT (Accelerated Shelf Life Testing) method or acceleration method which was applied Arrhenius model with zero reaction orde and one reaction orde. This research had been done by two steps including preliminary research and main research. The experiment reported the best resulted of chlorophyll content analyze and antioxidant activity on chlorophyll extracts was performed at Cu2+ with 0 ppm concentration, therefore no addition Cu2+ on the chlorophyll extract drink. The best combination of tea amount and boil water at 85˚C to phenol total analyze and antioxidant activity was identified on 1.25: 100 (w/v). The formulation of ingredient consist of refined sugar 12 % (w/v), sitric acid 0,018 % (w/v), CMC 0,05 % (w/v), green tea 1,25 g/100 ml water, and chloropyll extract (10; 20; 30) ml/100 ml for each product. The first, second, and third sample were indicated 2.9; 2.9; and 2.9 for flavor score, 3.6; 3.5; and 3.4 for taste score, 3.5; 3.2; and 3.1 for color score; 3.6; 3.3; and 3.2 for overall score of organoleptic test. Organoleptic test had shown no significant effect. The experiment reported the best resulted of antioxidant activity was performed at third sample. The total bacterial analysis indicated that both of them period was described the value of Standard Plate Count < 2.5 x 102 colony/ml. The variable of ASLT (Accelerated Shelf Life Testing) was used including antioxidant activity value for sample which was sterilized until 10 min have shelf life 223 days at 25 oC respectively and in 15 min have shelf life 235 days at 25 oC respectively. Therefore the sterilization time was using sterilization 15 min than 10 min caused the shelf life was a long time. Based on the experiment indicated the optimal combination value of green tea to boil water was 1.25: 100 (w/v) at 85 oC. It also known the best ingredient formulation were refined sugar 12 % (w/v), sitric acid 0,018 % (w/v), CMC 0,05 % (w/v), green tea 1,25 g/100 ml water, and chloropyll extract 30 ml/100 ml to product based on organoleptic test and antioxidant activity. The sterilization processed of product for 15 min with 121 oC was better than product which was sterilized for 10 min with 121 oC.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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