Sri Raharjo
Jurusan Teknologi Hasil Pertanian, Fakultas Teknologi Pertanian, Universitas Gajah Mada, Yogyakarta

Published : 77 Documents
Articles

AKTIVITAS ANTIOKSIDAN ANTOSIANIN BERAS KETAN HITAM SELAMA FERMENTASI [Antioxidant Activity of Anthocyanin of Black Glutinous Rice During Fermentation]

Jurnal Teknologi Dan Industri Pangan Vol 24, No 1 (2013): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

AKTIVITAS ANTIOKSIDAN ANTOSIANIN BERAS KETAN HITAM SELAMA FERMENTASI [Antioxidant Activity of Anthocyanin of Black Glutinous Rice During Fermentation] Nanik Suhartatik1)*, Muhammad Nur Cahyanto2), Sri Raharjo2) dan Endang S. Rahayu2) 1) Fakultas Teknologi Pertanian, Universitas Slamet Riyadi Surakarta, Surakarta 2) Jurusan Teknologi Hasil Pertanian, Fakultas Teknologi Pertanian, Universitas Gajah Mada, Yogyakarta   Diterima 07 November 2012 / Disetujui 22 Juli 2013 ABSTRACT   Anthocyanin is a group of bioactive compound found to be abundant in black glutinous rice. It has been widely studied for their health beneficial effect. Hydrolysis of anthocyanin glycoside into anthocyanidin and sugar by β,D-glucosidase is presumed to be the first step in anthocyanin metabolism. Enzymatic degradation of anthocyanin was reported to produce not only more stable compounds, but also healthier compounds with better bioavailability. Some species of Lactic Acid Bacteria showed β,D-glucosidase activity. The research aims to study the functional property’s change’s of anthocyanin extracted from black glutinous rice as an antioxidant compound after being fermented using Lactobacillus plantarum Mut 7. The results showed that fermentation process did not give a significant effect to the antioxidant activity of black glutinous rice anthocyanin. The antioxidant activity as determined by Radical Scavenging Activity and Ferrous Reducing Activity Power value were 59.2% (6 hours of incubation, 30 mM anthocyanin) and 96.7% (5 hours of incubation, 10 mM anthocyanin). The lactic acid bacterial count increased up to 2 log cycle after being fermented for 5 hours.  

The Role of Surfactant Micelles on the Partitioning of Antioxidant and the Oxidative Stability of Oil-in-Water Emulsion

Jurnal Teknologi Dan Industri Pangan Vol 19, No 1 (2008): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

Lipid oxidation system in which the fat is dispersed as emulsion droplets is still not well understood, although a large number of food exist partially or entirely in the form of emulsions. Therefore, this study was intended to examine how surfactant micelles influence the partitioning of antioxidant and hydroperoxides and how it alter the oxidative stability of oil-in-water emulsion. To determine the ability of surfactant micelles upon the partitioning of antioxidant in oil-in-water emulsion, this type of emulsion, containing quercetin at 0, 25, 50, 75 and 100 ppm, were prepared with polyoxyethylene 100 stearyl ether (Brij 700) or polyoxyethylene sorbitan monolaurate (Tween 20) with acetate or phosphate buffer (pH 3.0 or 7.0). Structurally Birj 700 has 5 times longer polyoxyethylene groups than Tween 20. After preparation of the emulsion, surfactant micelles (0-2%) were incorporated into the continuous phase to give a final lipid concentration of 5%. Lipid oxidation rates, as determined by the formation of lipid hydroperoxides, decreased with increasing quercetin concentrations. At pH 3, the peroxide value was higher than that at pH 7. Brij 70 decreased production of lipid hydroperoxides from palm oil-in-water-emulsions compared to the emulsions stabilized by Tween 20. the result showed that solubilization of quercetin into the aqueous into the aqueous phase by Brij or Tween micelles did not alter the oxidative stability of palm oil-in-water emulsion, suggesting that surfactant micelle influenced the oxidation rate by mechanism other than antioxidant solubilization. Key word : Quercetin, surfactant micelles, and oxidative stability

Oxidative Stability of Canarium Nut (Canarium indicum and Canarium vulgare) Oil during Storage at 30 and 40 0 C

Jurnal Teknologi Dan Industri Pangan Vol 19, No 2 (2008): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

The aims of this research were to study the effect of temperature and storage on the oxidative stability of crude and refined canarium nut oil extracted from the seeds of Canarium indicum and Canarium vulgare. The experiment was designed to include storage of two type of canarium nut oil at two different temperatures for up to 35 days. The oils (crude and refined) used had the similar condition. Parameter used for oxidative deterioration indicators were two peroxide value, TBARS (thiobarbituric acid reactive substances), and free fatty acid value. The result showed that refining oil can decrease component natural antioxidant of canarium oil cause more sensitive to the oxidation. Increased storage temperature can raise oxidation of crude and refined oils from both species Canarium. The peroxide values of crude and refined oils both Canarium indicum and Canarium vulgare stored at 30 °C were 2.17, 4.35, 3.36 and 3.77 meq O2/kg oil, respectively. When they were stored at 4?C the similar results were 6.21, 19.09, 8.12 and 17.23 meq O2/kg oil. Furthermore, TBARS value of crude and refined oils both for Canarium indicum and Canarium vulgare stored 30?C were 4.55, 7.78, 5.70 and 6.58 µmol MDA/kg oil. When they were stored at 40 °C the similar results were 9.99, 55.46, 12.46 and 43.62 µmol MDA/kg oil.Key words: Canarium nut oil, peroxide value, TBARS

The Effect of Size Reduction and Preparation Duration on The Antioxidant Activity of White Saffron (Curcuma mangga Val.)

Journal of Food and Pharmaceutical Sciences Vol 1, No 1 (2013): J.Food Pharm.Sci (January-April)
Publisher : Gadjah Mada University

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Abstract

Food processing is usually conducted through preparation stages such as peeling, slicing, or cutting. The purpose of this research was to determine the correlation between the antioxidant activity and the total phenolic compounds of white saffron as affected by different level of size reduction and the duration of rhizome preparation at room temperature. White saffron rhizomes were peeled, washed, and cut into 1x1x1 cm3. The whole white saffron was sliced diagonally at thickness of 4 x 2 mm, and grated. The antioxidant activity of the white saffron was determined by radical scavenging activity using 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical and by ferric reducing antioxidant power FRAP) method. The total phenol and total flavonoid contents were also determined at 2, 4, and 6 hours, respectively. The result showed that the antioxidant activities, total phenolic and flavonoid contents due to the preparation of whole white saffron for 6 hour are not statistically different compared to those of fresh white saffron. The preparation of white saffron sliced at 2 mm and grated for 2 hour showed a significant decrease in the antioxidant activities, compared to those of fresh white saffron.Keywords: white saffron, preparation duration, antioxidant activity, total phenol

Mechanism and Kinetics of Quenching of Quercetin on Photosensitizing Effect of Synthetic Food Colorant Erythosine in Palm Oil Oxidation

Jurnal Teknologi Dan Industri Pangan Vol 16, No 2 (2005): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

The effect 0, 200, 400, 600, 800 and 1000 ppm (wt/vol) quercetin on the singlet oxygen oxidation of palm oil in methylene chloride containing 100 ppm erythrosine, were studied during storage under 400 lux fluorecent light for 5 h by measuring peroxide value. Steady-state kinetic approximation was used to determine the quenching mechanism and quenching rate constant of quercetin in the erythrosine-sensitized photo oxidation of palm oil. Erythrosine greatly increased the As photo oxidation of palm oil, as was expected. Quercetin was extremely effective at minimizing erythrosine-sensitized photo oxidation of palm oil. As the concentration of quercetin increased from 0 to 200, 400, 600, 800 and 1000 ppm, the peroxide value of palm oils decreased significantly (p

The Influence of Particle size and Guluronic/Mannuronic Proportion of Alginate on Physical and Sensory Characteristics of Restructured Products from Soursop

Jurnal Teknologi Dan Industri Pangan Vol 14, No 3 (2003): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

The application of restructuring technology is intended to add value for local fruits. Fresh and ripe sour sop fruits are frequently of having defective appearance, irregular shape and size, or showing signs of insect infestation which make the whole fruit is less acceptable by consumers. Previous study has indicated that sour sop fruit can be restructured into a fresh fruit product with acceptable sensory characteristics using calcium alginate gel system. This particular study was intended to determine the effect of alginate powder particles size and its guluronic/mannuronic proportion on the physical and sensorial properties of restructured sour sop. The restructured fruit product was evaluated based on its gel strength, pH colour, and sensory attributes which include taste, aroma, mouth feel, appearance, and hardness. Sour sop restructured by internal setting with coarse alginate powder (36 mesh) tend to have softer gel compared to the use of fine alginate powder (120 mesh). Different proportion of guluronic/mannuronic in the alginate used for the restructurization resulted in the same gel strength when calcium lactate powder was used. However, the use of encapsulated calcium lactate resulted in stronger gel with alginate containing higher proportion of mannuronic acid. The alginate particle size and proportion of guluronic/mannuronic content showed no significant difference in product colour and sensory attributes evaluated. Key words : Alginate, sour sop fruit, restructurization.

Mechanism and Kinetic of Antiphotooxidation of Bixin in Metil Linoleat System

Jurnal Teknologi Dan Industri Pangan Vol 17, No 3 (2006): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

Bixin belongs to the carotenoid group, present in Bixa orellana tree. It has conjugated double bonds which plays a role as an antiphotooxidant. The objectives of this study were to analyze the quenching mechanisms and kinetics of bixin in photosensitized oxidation of methyl linoleate. The quenching mechanism and kinetic of bixin were studied by the steady-state kinetic method. Samples of 0, 0.25 x 10-5, 0.5 x 10-5, 0.75 x 10-5, 1.0 x 10-5, 2.0 x 10-5 and 3.0 x 10-5 M bixin were prepared in ethanol that also contained 0.03, 0.06, 0.09 and 0.12 M methyl linoleate and 11.36 x 10-6 M of erythrosine stored under fluorescent light (4000 lux) at room temperature for 2 hours. The extent of photosensitized oxidation of methyl linoleate was expressed as peroxide value. The steady-state kinetic study indicated that bixin quenched singlet oxygen and exhibited triplet sensitizer quenching mechanism (to minimize the erythrosine photosensitized oxidation of methyl linoleate). The total quenching rate constant of bixin was 7.7 x 109 M-1S-1. Key words: bixin, quencher, erythrosine, singlet oxygen

ISOLASI DAN IDENTIFIKASI RHIZOPUS OLIGOSPORUS PADA BEBERAPA INOKULUM TEMPE

Agrotekno Vol. 11, No. 2 Januari 2005
Publisher : Agrotekno

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Abstract

The research was aimed to isolate the fungi grown and to identify R. oligosporus inseveral tempe inoculum samples.Seventy microbes were isolated from tempe inoculum, which was consisted of 58greyish brown conidia, and 12 grey conidia isolates. All isolates were belong to genera ofRhizopus. Seven of them were selected based on their origin of tempe inoculum, conidiacolour, growth of mycelia, and conidia mass. Macroscopic and microscopic observationshowed that the selected isolates were R. oligosporus.

SIFAT-SIFAT FISIK DAN SENSORIS PRODUK BUAH HASIL RESTRUKTURISASI NON-TERMAL SELAMA PENYIMPANAN DINGIN [Physical and Sensoric Properties of Restructured Fruit During Refrigerated Storage]

Jurnal Teknologi Dan Industri Pangan Vol 12, No 1 (2002): Jurnal Teknologi dan Industri Pangan
Publisher : Departemen Ilmu dan Teknologi Pangan, IPB Indonesia bekerjasama dengan PATPI

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Abstract

SIFAT-SIFAT FISIK DAN SENSORIS PRODUK BUAH HASIL  RESTRUKTURISASI NON-TERMAL SELAMA PENYIMPANAN DINGIN [Physical and Sensoric Properties of Restructured Fruit During Refrigerated Storage] Sri Raharjo 1) , dan  Zaki Utama 1) 1) Fakultas Teknologi Pertanian, UGM- Yogyakarta ABSTRACT The objective of this experiment was to develop novel restructured products from tropical fruits. A model fruit product was developed using fresh tropical fruits puree (avocado, mango, jackfruit, sapodilla, and soursop) and calcium-alginate gel forming methods (internal setting). As binding system low viscosity alginate  and three different calcium sources (Ca-lactate, Ca-chloride and encapsulated Ca-lactate) were used. Gel forming was conducted  by internal setting and calcium was released under controlled conditions simultaneously throughout the system. The products were  then stored at 4 oC for  9 days. Sensory evaluation indicated that restructured sapodilla with Calactate or encapsulated Ca-lactate (1%) had better taste as compared to product were with Ca-chloride. Different calcium sources had no significant effect on flavor as compared to those of fresh fruit. During refrigerated storage, however, products prepared with soursop and avocado suffered discoloration. Calcium, lactate or encapsulated Ca-lactate produced weaker gel than that of calcium chloride. Restructured fruits that have been stored up 9 days were  still considered acceptable by panelists.   Key words : Tropical  fruits, calcium-alginate gel, and restructured

Degradasi Biksin Selama Pemanasan dan Pencahayaan

Agritech Vol 26, No 4 (2006)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

The kinetics of thermal and light induced degradation of natural bixin in a mixture of ethanol and 2 % acetic acid (80 : 20) was studied as a function of temperatures 80, 98, and 125 OC for 120 minutes. Illumination was carried out either under fluorescent or incandescent lights, both at 4000 lux for 300 minutes. The bixin concentration during heating and illumination was analysed using HPLC. The method to determine the degradation rate constant for the decay of the products from bixin was obtained using a linear regression according to first order reaction.  The results indicated that the degradation rates of bixin at 125 OC were 5.5 and 3.8 times faster than that of 80 OC and 98 OC, respectively. The energy activation of bixin was 9.82 kcal/mol. The photodegradation rate constants of bixin under incandescent or fluorescent illumination was 2.8 x 10-3 and 3.3 x 10-3 minutes-l, respectively.