Physicochemical Properties of Brown Rice as Influenced by Gamma-Irradiation, Variety and Storage.

Effects of gamma-irradiation, variety and storage on physicochemical properties of brown rice from three Louisiana rice varieties: Mars, a medium grain variety, Lemont and Tebonnet, long grain varieties, were determined. Cooking time was significantly reduced in Mars and Lemont at doses of 200 and 300 Krads. Irradiation increased cooking rate, water uptake at 80\sp\circC, water uptake ratios, total solids content in residual cooking liquid and starch damage from 100 to 300 Krad samples. Water uptake at 96\sp\circC generally decreased with increasing dose levels. Evidence indicated alterations in the rice grain structure and composition. The component drastically affected by gamma-irradiation was starch as shown by reduced cooking time, increased water uptake, increased amounts of starch and protein in residual cooking liquid, reduced volume expansion, increased damaged starch and changes in amylographic pasting characteristics. Scanning electron microscopy showed more simple starch granules in irradiated samples than in nonirradiated samples. Structural changes in the bran layer due to gamma-irradiation were not evident from electron micrographs. Amylose, moisture, fat and protein content were not significantly affected by gamma-irradiation. Total color difference values indicated that brown rice darkened on irradiation and, became lighter on storage. Some changes in irradiated samples on storage were similar to those in nonirradiated samples but the degree of these changes was dependent upon dose. Fat acidity values for irradiated Mars and Lemont samples were generally lower than nonirradiated samples. 100 Krad samples of Tebonnet were higher than that of 0 and 200 Krad samples. Fat acidity values of nonirradiated and irradiated samples of Mars, and nonirradiated samples of Lemont increased on storage while irradiated samples were not significantly affected. Values for Tebonnet were not significantly affected by storage. TBA values for Lemont decreased from that at 0 to 100 Krads and then increased at 200 Krads. There was no definite trend in TBA values for Mars. Dose effects on TBA values were insignificant for Tebonnet. On storage, irradiated samples of Lemont and Tebonnet had lower values than nonirradiated samples. Stored irradiated samples of Mars tended to have higher values than nonirradiated samples

Feeding Value of Palm Kernel Meal in Layer Diet

ABSTRACT A total of forty eight 22-week old Single Comb White Leghorn (SCWL) were used to evaluate the feeding value of palm kernel meal (PKM) iii layer diet 11w pullets were randomly assigned to four groups of treatment in Completely Randomized Designed (CRD) and rod their respective diets containing 0%, 5%, 10% and 15% PKM Weekly feed consumption, feed efficiency, cm production and egg weight were moluioied for 12 weeks. During the period yolk color and shell thickness were also measured Inweelitly Nutrient digestibility of four treatments ration were examined as a suporting data. All data were analyzed using spirt plot in time in CRD. Trend comparison was used to determine the linear, quadratic and cubic effect of the inclusion levels of PKM (Gomez and Gomez, 1984). A significant interaction between levels of PKM m the diet and wevIcs of feeding was observed on all parameters measured (

Developm ent of carboxymethylcellulose from nata de coco

Nata de coco was used as raw material for the preparation of food-grade carboxymethylcellulose referred to as carboxymethyl-nata (CMN). The effect of various conditions in the carboxymethylation of nata cellulose was determined. The concentration of NaOH, mercerisation time, shredding time during mercerisation and etherification, and the concentration of monochloroacetic acid significantly affected the following physico-chemical properties of CMN, namely, degree of substitution (DS), viscosity, degree of polymerisation (DP), and solubility. The best processing conditions were: the use of 40% NaOH, 60 mins mercerisation time, 60 mins shredding time during mercerisation and etherification, and J.35g/mL ClCH COOH. CMN with desirable properties was produced using these conditions

Developm ent of carboxymethylcellulose from nata de coco

Nata de coco was used as raw material for the preparation of food-grade carboxymethylcellulose referred to as carboxymethyl-nata (CMN). The effect of various conditions in the carboxymethylation of nata cellulose was determined. The concentration of NaOH, mercerisation time, shredding time during mercerisation and etherification, and the concentration of monochloroacetic acid significantly affected the following physico-chemical properties of CMN, namely, degree of substitution (DS), viscosity, degree of polymerisation (DP), and solubility. The best processing conditions were: the use of 40% NaOH, 60 mins mercerisation time, 60 mins shredding time during mercerisation and etherification, and J.35g/mL ClCH COOH. CMN with desirable properties was produced using these conditions

IMMOBILIZATION OF INVERTASE ON CARBOXYMETHYLCELLULOSE PREPARED FROM NATA DE COCO FOR THE INVERSION OF SUCROSE

Nata de coco, the cellulose produced by Acetobacter aceti with coconut water as substrate, was used as starting material in the synthesis of carboxymethylcellulose after treatment with NaOH and monochloroacetic acid. The product, referred to as carboxymethyl-“nata” (CMN), had a degree of substitution of 0.76, a higher value than those previously reported. This was used in the immobilization of invertase via ionic interaction and adsorptive forces, which produced a viscous colloidal suspension. Agar was incorporated to facilitate pellet formation. Interactions between the agar and the CMN-invertase may have resulted from ionic interactions as well as H-bonding. The immobilized enzyme retained 71% of its initial activity and exhibited optimum pH of 4.5 and an optimum temperature of 55°C. It was more sensitive to pH and temperature changes. The Michaelis constant, Km, was 107.43 mM for the immobilized enzyme, and 71.42 mM for the free enzyme. The Vmax values were 89.28 µmole min-1 and 82.64 µmole min for the free and immobilized enzyme, respectively. Statistical analyses showed that V values did not vary significantly. The higher K of the immobilized enzyme may be attributed to diffusional effects, steric hindrance and conformational modifications of the enzyme. The immobilized enzyme has potential for further applications because of its stability with storage, repeated and continuous use

IMMOBILIZATION OF INVERTASE ON CARBOXYMETHYLCELLULOSE PREPARED FROM NATA DE COCO FOR THE INVERSION OF SUCROSE

Nata de coco, the cellulose produced by Acetobacter aceti with coconut water as substrate, was used as starting material in the synthesis of carboxymethylcellulose after treatment with NaOH and monochloroacetic acid. The product, referred to as carboxymethyl-“nata” (CMN), had a degree of substitution of 0.76, a higher value than those previously reported. This was used in the immobilization of invertase via ionic interaction and adsorptive forces, which produced a viscous colloidal suspension. Agar was incorporated to facilitate pellet formation. Interactions between the agar and the CMN-invertase may have resulted from ionic interactions as well as H-bonding. The immobilized enzyme retained 71% of its initial activity and exhibited optimum pH of 4.5 and an optimum temperature of 55°C. It was more sensitive to pH and temperature changes. The Michaelis constant, Km, was 107.43 mM for the immobilized enzyme, and 71.42 mM for the free enzyme. The Vmax values were 89.28 µmole min-1 and 82.64 µmole min for the free and immobilized enzyme, respectively. Statistical analyses showed that V values did not vary significantly. The higher K of the immobilized enzyme may be attributed to diffusional effects, steric hindrance and conformational modifications of the enzyme. The immobilized enzyme has potential for further applications because of its stability with storage, repeated and continuous use