Removal of Cyanides from Gadung (Dioscorea hispida Dennst.) Tuber Chips using Leaching and Steaming Techniques

Gadung (Dioscorea hispida Dennst.) has been considered as one of staple foods in Indonesia. However, its high cyanides content has limited its utilisation for commercial food production. This work is aimed to investigate the removal of cyanides content from gadung tuber chips through two consecutive treatments, i.e. leaching and steaming and to propose mathematics model for the leaching process. The results showed that processing water flow rate and leaching time affected the efficiency of cyanides removal in the leaching process. The proposed mathematical model was able to represent the removal of cyanides through leaching process very well. The cyanides content removal was also found to be affected by steaming time. Best processing condition was at leaching using 5.00 10-5 m3.s-1 for 3,600 s, followed by steaming for 3,600 s to obtain cyanides content of 29.9 mgkg-1. While the yielded gadung tuber chips are considered as safe for consumption, further research on physicochemical characteristic of the gadung tuber flour is necessary for its utilisation consideration

Preparation, Proximate Composition and Culinary Properties of Yellow Alkaline Noodles from Wheat and Raw/Pregelatinized Gadung (Dioscorea Hispida Dennst) Composite Flours

The steady increase of wheat flour price and noodle consumptions has driven researchers to find substitutes for wheat flour in the noodle making process. In this work, yellow alkaline noodles were prepared from composite flours comprising wheat and raw/pregelatinized gadung (Dioscorea hispida Dennst) flours. The purpose of this work was to investigate the effect of composite flour compositions on the cooking properties (cooking yield, cooking loss and swelling index) of yellow alkaline noodle. In addition, the sensory test and nutrition content of the yellow alkaline noodle were also evaluated for further recommendation. The experimental results showed that a good quality yellow alkaline noodle can be prepared from composite flour containing 20% w/w raw gadung flour. The cooking yield, cooking loss and swelling index of this noodle were 10.32 g, 1.20 and 2.30, respectively. Another good quality yellow alkaline noodle can be made from composite flour containing 40% w/w pregelatinized gadung flour. This noodle had cooking yield 8.93 g, cooking loss 1.20, and swelling index of 1.88. The sensory evaluation suggested that although the color, aroma and firmness of the noodles were significantly different (p ≤ 0.05) from wheat flour noodle, but their flavor remained closely similar. The nutrition content of the noodles also satisfied the Indonesian National Standard for noodle. Therefore, it can be concluded that wheat and raw/pregelatinized gadung composite flours can be used to manufacture yellow alkaline noodle with good quality and suitable for functional food

Preparation of Wine from Jackfruit (Artocarpus heterophyllus lam)Juice Using Baker yeast: Effect of Yeast and Initial Sugar Concentrations

The overproduction of jackfruit (Artocarpus heterophyllus Lam) during harvest season and its short shelf-life have caused serious losses for farmers. Fortunately, high sugar content of the fruit pulp makes the juice a potential substrate for wine production. This work was purposed to investigate the effect of yeast and initial sugar concentrations on jackfruit juice wine fermentation. Clarified jackfruit juice of 14 % w/w sugar concentration was fermented using 0.5 to 2.0 % w/v Baker’s yeast (Saccharomyces cerevisiae) under anaerobic condition at 30°C for 14 days. Samples were collected daily for ethanol and sugar contents analysis. The profile of sugar and ethanol concentration as function of fermentation time, showed that higher yeast inoculums rate and initial sugar concentrations inhibited growth of yeasts. The fermentation of original jackfruit juice of 14 % w/w sugar concentration using 0.5% w/v yeast for 9 days was the best to produce a good quality wine with 12.13% v/v of ethanol and specific jackfruit aroma

Solubility of Delphinidin in Water and Various Organic Solvents between (298.15 and 343.15) K

The solubilities of 2-(3,4,5-trihydroxyphenyl)chromenylium-3,5,7-triol (delphinidin) in water, methanol, ethanol, and acetone have been measured spectrophotometrically at various temperatures ranging from (298 to 343) K under atmospheric pressure. Delphinidin is most soluble in methanol, followed by water, ethanol, and acetone at all measured temperatures. The experimental data were correlated using the modified Apelblat equation. The calculated solubilities for all solvents showed good agreement with the experimental data in the temperature range studied

Influence of Temperature and Solid Concentration on the Physical Properties of Noni (Morinda citrifolia L.) Juice

The effect of temperature on the physical properties of fresh noni (Morinda citrifolia L.) juice with three different solid concentrations (5, 10, and 15°Brix) was investigated. The flow behaviour index (n) and thermal conductivity (k) were found to increase with the increase in temperature. On the other hand, the juice density (ρ) and consistency coefficient (K) were found to decrease with increasing temperature. The increase in solid concentration leads to increase juice density and consistency coefficient, but reduce flow behaviour index and thermal conductivity. The experimental data were then correlated with temperature and solid concentration using nonlinear regression equations or empirical models. It was found that the physical properties calculated using proposed equations agree well with the experimental data with coefficient of determinations (R2) ranged from 0.9897 to 0.9998

PEMBUATAN KHITOSAN DARI KULIT UDANG UNTUK MENGADSORBSI LOGAM KROM (Cr6+) DAN TEMBAGA (Cu)

Khitosan adalah hasil proses deasetilasi dari senyawa khitin yang banyak terdapat dalam kulit luar hewan golongan Crustaceae seperti udang dan kepiting. Elektron nitrogen pada gugus amino yang dimiliki khitosan dapat mengikat ion-ion logam, membentuk senyawa kompleks koordinasi yang stabil. Oleh karena itu, khitosan dapat digunakan untuk mengadsorbsi logam berat hasil buangan industri seperti krom dan tembaga yang bersifat karsinogenik dan berbahaya bagi tubuh manusia. Kemampuan khitosan untuk menjerap limbah logam tergantung pada derajat deasetilasinya. Proses adsorbsi dipengaruhi oleh beberapa faktor antara lain jumlah adsorbent, pH, waktu, kecepatan pengadukan dan suhu. Percobaan dibagi dalam dua tahap. Tahap pertama adalah pembuatan khitosan dari kulit udang, dengan konsentrasi NaOH dari 20 hingga 60% (%berat). Khitosan yang dihasilkan dari proses ini dianalisa derajat deasetilasinya dengan FTIR. Tahap kedua adalah proses adsorbsi limbah krom dan tembaga menggunakan khitosan dengan derajat deasetilasi yang paling besar. Pada proses ini waktu adsorbsi divariasi untuk limbah logam krom sedangkan untuk limbah tembaga menggunakan variabel berubah pH dan waktu. Limbah krom dan tembaga kemudian dianalisa dengan AAS. Hasil penelitian menunjukkan bahwa derajat deasetilasi khitosan yang optimum sebesar 91,88% diperoleh pada konsentrasi NaOH 50%, waktu optimum untuk proses adsorbsi limbah krom adalah 30 menit dengan kadar krom sebesar 13,96 ppm sedangkan untuk adsorbsi Cu optimum pada pH 3 dengan kadar 0,24 ppm dan efisien untuk waktu 30 menit

Effect of Time and Solvent/Feed Ratio on the Extraction of Mannan from Aloe Vera Leaf Pulp

Mannan is one of oligosaccharides contained in the Aloe Vera leaf pulp gel, which exhibits promising potential as a raw material of edible coating due to its antimicrobial, antifungal, coating and drying properties. The objective of this work was to investigate the effect of time and solvent/feed ratio on the extraction of mannan from A. Vera leaf pulp. Extraction was carried out in a three necked flask equipped with mechanical agitator, Leibig condenser and thermometer. Two hundreds grams of A. Vera leaf pulp was juiced and the remaining pellet was then subjected to water extraction at 40oC and certain solvent/feed ratios for a specified time. Upon precipitation of A. Vera juice and supernatant by addition of ethanol, the precipitated extract was lyophilized and determined its mannan content. The optimum extraction time was found to be 45 minutes where reasonable yield and rendemen were obtained with highest extract purity. The optimum feed/solvent ratio was 4, where highest yield and rendemen were obtained at good extract purity. Hydrolysis was likely to happen when feed/solvent ratio higher than 4 as excess water at warm temperature causing reduction of extraction yield and rendemen. The proposed mathematical model suited the experimental data very well

Microwave Assisted Synthesis and Characterization of Acetate Derivative Cassava Starch

The aims of this study were to observe the possibility of application of microwave heating in the acetylation of cassava starch and to study the physicochemical properties of the starch acetate obtained. The acetylation was carried out by mixing native cassava starch with chloroacetic acid and sodium hydroxide of a certain weight ratio in a sealed container. The mixture was then sprayed with ethanol and heated using microwave power. The degree of substitution (DS), reaction efficiency (RE) and some physical properties of the acetylated starches were then analyzed. It was found that microwave assisted acetylation of cassava starch using chloroacetic acid can be done in a very short reaction time. The highest DS and RE obtained were 0.045 and 0.051%, respectively. Acetylation of cassava starch reduced gel hardness during storage. Acetylation also inhibits the retrogradation of starch gel. Cassava starch acetylation changed starch molecular motion, resulting in a decrease in the glass transition temperature. Amylopectin retrogradation was not significantly reduced, indicating that the degrees of modification of the starches in this study were too low to cause enough steric hindrance to prevent retrogradation. The modifications were done on native starch granules; they took place preferentially on the amylose fraction, not the amylopectin fraction, thus leaving amylopectin retrogradation was mostly unaffected. It can be concluded that microwave heating can be applied in the acetylation of cassava starch to obtain significant changes of the properties of starch