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1. Effect of microwave power and extraction time on the yield of highly-valuable vegetable oil and microstructure during microwave-assisted extraction of roselle seeds.

Author

Kumoro, Andri Cahyo, Retnowati, Diah Susetyo, and Mutiarini, Amanah

Subjects
*VEGETABLE oils, *ROSELLE, *COMPOSITION of seeds, *SEEDS, *MICROWAVES, *OILSEEDS
Abstract

The increasing demand for healthy vegetable oils has encouraged researchers around the world to find their new and sustainable sources. In addition, the needs for more efficient and environmentally benign technologies for vegetable oil extraction has also received more attention from both researchers and industries. This study aims to investigate the influence of microwave on the extraction yield and microstructure of roselle seeds as a promising candidate of vegetable source. The extraction was performed using conventional Clevenger apparatus employing a microwave oven as the heating equipment at various microwave power and extraction time. The results show that increasing microwave power accelerated the release of oil from roselle seeds and subsequently shortened the extraction time. Microwave power also demonstrated its role to alter roselle seeds microstructure. The microwave-assisted extraction of vegetable oil from roselle seeds required a roselle seeds mass to solvent volume ratio of 1:6 and microwave power of 400 W for 20 minutes to successfully achieve 16.03% % yield. Further research on the roselle seeds oil composition and physical properties may be necessary to provide a more comprehensive information on the roselle seeds oil, extraction method, physicochemical properties, and applications. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Estimation of aqueous solubility of starch from various botanical sources using Flory Huggins theory approach.

Author

Kumoro, Andri Cahyo, Retnowati, Diah Susetyo, Ratnawati, Ratnawati, and Widiyanti, Marissa

Subjects
*SOLUBILITY, *CLAUSIUS-Clapeyron relation, *STARCH
Abstract

The data of aqueous solubility of starch are essential for the determination of appropriate uses of starch and design of starch based food products. Unfortunately, these data are scarce and often, some are inconsistent. The aqueous solubility of starches from various botanical sources (tuber, cereal and legume) at 338.2 to 368.2 K were measured following the shake-flask method with necessary modifications. In general, the aqueous solubility of starches enhanced significantly as the system temperature increased. The newly developed solubility model as a combination of Clausius–Clapeyron relation and Flory Huggins theory was fitted to the aqueous solubility data of the starches. The model exhibits excellent aqueous solubility prediction of cereal, tuber and legume starches. Composition exhibits stronger effect on the Flory Huggins interaction parameter than the temperature. In conclusion, Flory Huggins approach can be used as a powerful tool in the estimation of aqueous solubility of starches. [ABSTRACT FROM AUTHOR]

Published
2021
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17. Extraction and Modification of Gum from Cashew Tree Exudates Using Wheat Starch and Glycerine

Author

Kumoro, Andri Cahyo, Retnowati, Diah Susetyo, and Budiyati, Catarina Sri

Abstract

Penelitian ini bertujuan untuk mengekstrak getah pohon mete dan memodifikasi sifatnya untuk dapat digunakan sebagai senyawa pembantu proses pengeringan menggantikan fungsi getah Arab. Dengan menggunakan getah mete termodifikasi dari penelitian ini, permasalahan biaya pada proses pengeringan jus buah dengan spray dryer dapat diatasi. Getah pohon mete dipungut dan diendapkan dari larutan hasil penyadapan dengan bantuan etanol sebagai antisolvent. Dalam penelitian ini gliserin dan pati gandum digunakan sebagai bahan tambahan untuk memodifikasi sifat getah. Hasil penelitian menunjukkan bahwa getah pohon mete termodifikasi yang dihasilkan memiliki kualitas yang baik dan kesamaan sifat dengan getah Arab. Kata kunci : getah pohon mete, getah Arab, modifikasi, pati, gliserin The objectives of this research were to extract cashew tree gum (CTG) from cashew tree exudates and to modify it into a new drying aid, which can act as a substitute for Arabic gum. The cost problem faced in the spray drying of fruit juices is expected to be solved with the use of modified CTG as a replacement of Arabic gum. The CTG was extracted and precipitated from its raw cashew exudates solution with the help of ethanol as antisolvent. Glycerine and wheat starch were the additives used in the modification of the gum. The good quality of modified CTG was obtained based on their close similarity to Arabic gum properties. Keywords: CTG, Arabic gum, modification, starch, glycerine

Published
2013

18. PHYSICAL, THERMAL AND FUNCTIONAL PROPERTIES OF FLOUR DERIVED FROM UBI GEMBILI (DIOSCOREA ESCULENTA L.) TUBERS GROWN IN INDONESIA.

Author

Retnowati, Diah Susetyo, Kumoro, Andri Cahyo, and Ratnawati, Ratnawati

Subjects
*RAW materials, *THERMAL properties of food, *GELATION
Abstract

Gembili (Dioscorea esculenta L.) tuber is one of the important food sources in term of cultural, nutritional and economic perspectives for the people in the Africa, Caribbean islands, Asia, and Oceania regions. The tubers can be eaten after being boiled, roasted, fried or cooked. However, there is lack of information on the advanced utilizations of the tubers as raw material in the manufacture of modern foods. This study aims to characterize the physical, functional and thermal properties of Gembili flour, so that this information can be used as the basis in the development of novel foods. The microstructure, crystallinity, gelatinization temperature, swelling power and solubility of the flour were determined. The electron microscope observation revealed that Gembili flour consisted of smooth surface oval granules, which were light brown in color and having 23 μm average diameter. They are comprised of polygonals or some clusters of irregular fragments. Similar to most of tuber flours, Gembili flour also exhibited B-type crystallinity with approximately 31 ±3.7% crystallinity. The gelatinization temperature of Gembili flour was high and being comparable to that of cereal flour. The enthalpy of gelatinization of Gembili flour (9.52 ±0.80 J.g-1) was comparable to that of Dioscorea alata. Unfortunately, Gembili flour exhibited low swelling power (3.90 ±0.01 g.g-1). The Gembili flour granules were highly soluble in water (11.07 ±0.05%). Based on those reported properties, Gembili flour can be a suitable raw material for the manufacture of bakery, cookies, noodle and infant foods. [ABSTRACT FROM AUTHOR]

Published
2018
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19. Modifikasi Pati Ketela Pohon Secara Kimia dengan Oleoresin dari Minyak Jahe

Author

Retnowati, Diah Susetyo, Kumoro, Andre Cahyo, and Budiyati, Sri

Abstract

Modifikasi pati akhir-akhir ini banyak dikembangkan dan dipakai untuk keperluan industri makanan, kertas dan tekstil. Modifikasi pati, khususnya secara kimia dilakukan untuk memperbaiki sifat-sifat fungsional pati, terutama jika untuk keperluan bahan dasar makanan. Modifikasi pati ketela pohon dilakukan dengan mereaksikan suspensi pati dengan minyak jahe yang mengandung zat aktif gingerol pada suhu kamar. Hasil percobaan modifikasi menunjukkan bahwa meningkatnya perbandingan antara pati/air/minyak jahe (b/v/v), menghasilkan pati termodifikasi dengan swelling power, kelarutan dan kerapatan cross-link yang lebih tinggi. Pada komposisi pati terhadap air dan minyak jahe, 300:400:0,4 (b/v/v) menghasilkan pati termodifikasi yang cocok digunakan sebagai bahan pengemas makanan yang dapat dimakan (edible food packaging) dengan nilai swelling power, kelarutan dan kerapatan cross-link adalah 7,3 kali; 6,662 mg/mL dan 780,69 rantai/cm3. Sedangkan komposisi pati:air:miyak jahe sebesar 300:300:0,3 (b/v/v) merupakan komposisi terbaik untuk menghasilkan pati termodifikasi sebagai bahan pangan dengan nilai swelling power, kelarutan dan kerapatan cross-link berturut-turut adalah 8,96 kali; 10,55 mg/mL, 203,85 rantai/cm3. Hasil analisis dengan scanning electron microscopy (SEM) menunjukkan bahwa modifikasi pati ketela pohon dengan teknik cross-linking ternyata tidak mengubah struktur permukaan butir pati. Kata kunci: reaksi suspensi, pati ketela pohon, gingerol, swelling power, cross-link Recently, starch modifications have been developed and are applied for food, paper and textile industries. In general, chemical modification has been done to improve starch functionality, especially for bread, cake and snack making. In the present work, suspension method was used to modify cassava starch by gingerol of crude ginger rhizome extract at room temperature. The effect of starch/water/gingerol (w/v/v) ratio on swelling power, water solubility, and cross-link density of the modified starch was investigated. In addition, scanning electron microscopy (SEM) analysis were also conducted to observe possible structural changes of the resulting starch. The experimental results showed that reactant composition that had a starch/water/gingerol (w/v/v) ratio of 300:400:0.4 produced modified starch suitable for edible coating with swelling power of 7.3 times, solubility of 6.662 mg/mL and cross-link density of 780.69 chains/cm3. Meanwhile, reactant having starch/water/gingerol (w/v/v) ratio of 300:300:0.3 produced modified starch that could be used for food with swelling power, solubility and cross-linking density of 8.96, 10.55 mg/mL and 203.85 chains/cm2, respectively. The cross-link densities achieved in this modification process were high and reproducible that indicated a strong interaction between starch and gingerol molecules in water as dispersant. However, there were no noticeable changes found from the micrograph of the SEM analysis on the external surface of the cassava starch. Keywords: suspension method, cassava starch, gingerol, swelling power, cross-link

Published
2012

21. Implementation of Steady State Approximation for Modelling of Reaction Kinetic of UV Catalysed Hydrogen Peroxide Oxidation of Starch.

Author

Kumoro, Andri Cahyo, Retnowati, Diah Susetyo, Ratnawati, and Budiyati, Catarina Sri

Subjects
*CHEMICAL kinetics, *HYDROGEN peroxide, *OXIDATION, *STARCH, *APPROXIMATION theory, *ULTRAVIOLET radiation
Abstract

With regard to its low viscosity, high stability, clarity, film forming and binding properties, oxidised starch has been widely used in various applications specifically in the food, paper, textile, laundry finishing and binding materials industries. A number of methods have been used to produce oxidised starch through reactions with various oxidizing agents, such as hydrogen peroxide, air oxygen, ozone, bromine, chromic acid, permanganate, nitrogen dioxide and hypochlorite. Unfortunately, most of previous works reported in the literatures were focused on the study of reaction mechanism and physicochemical properties characterization of the oxidised starches produced without investigation of the reaction kinetics of the oxidation process. This work aimed to develop a simple kinetic model for UV catalysed hydrogen peroxide oxidation of starch through implementation of steady state approximation for the radical reaction rates. The model was then verified using experimental data available in the literature. The model verification revealed that the proposed model shows its good agreement with the experimental data as indicated by an average absolute relative error of only 2.45%. The model also confirmed that carboxyl groups are oxidised further by hydroxyl radical. The carbonyl production rate was found to follow first order reaction with respect to carbonyl concentration. Similarly, carboxyl production rate also followed first order reaction with respect to carbonyl concentration. The apparent reaction rate constant for carbonyl formation and oxidation were 6.24 × 104 s-1 and 1.01 × 104 M-1.s-1, respectively. While apparent reaction rate constant for carboxyl oxidation was 4.86 × 104 M-1.s-1. [ABSTRACT FROM AUTHOR]

Published
2015
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