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T. C. A. MCGANN J. A. O'CONNELL ROSARIO MCFEELY 《International Journal of Dairy Technology》1975,28(1):23-27
An integrated procedure for the rapid determination of total protein and heat treatment classification of skim milk powders by dye binding is described. Total protein values estimated by the Pro-Milk were in good agreement with the macro-Kjeldahl method; the correlation coefficient was +0–98 and the SD of the differences between the two methods was ±0.55, corresponding to a CV of ±1.52 per cent. Residual undenatured whey protein was measured by the Pro-Milk difference (PMD) method on undiluted isoelectric filtrates. These were prepared by addition of acetic acid - sodium acetate buffer to reconstituted skim milk powders. The undenatured whey protein levels thus determined correlated well with the ADMI Kjeldahl procedure. The reproducibility of the PMD method in our laboratory was ±0.010, and satisfactory reports on the reliability of the Pro-Milk procedure have been received from industry. It is recommended that future heat treatment classifications of milk powders should be based on dye binding. Furthermore, it is proposed that milk powders should be heat classified according to the percentage of undenatured whey protein to total protein in the reconstituted milk and expressed as the whey protein ratio (WPR) of the milk powder. 相似文献
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Thiamin retention in extruded cowpea, mungbean, defatted soybean and air classified mungbean products was studied by a least squares regression equation using process temperature, screw speed, buffer pH and moisture content as the major independent variables. The increase in process temperature, pH and screw speed variables effected the decrease of thiamin retention values, while the increase in moisture content increased retention. The heat generation due to increase of stress force caused by increased screw speed presumably resulted in the thiamin retention values which were lower than expected. The carbohydrate and protein of the feed material flours pro-tected the thiamin during the thermoplastic extrusion process. 相似文献
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GONZALO L. ALONSO M ROSARIO SALINAS JOSÉ GARIJO M ANGELES SÁNCHEZ-FERNÁNDEZ 《Journal of food quality》2001,24(3):219-233
A method for simultaneous identification and quantification of crocins and picrocrocin by HPLC-DAD in aqueous extracts of saffron spice was used. The coefficients of variation obtained were lower than 10% for a majority of the crocins and picrocrocin. These substances are not found as standard compounds, for this reason it was necessary to obtain the response factor for each compound by collecting the fractions of each chromatographic peak and by using molar absorpitivity. This method can be used not only for crocins and picrocrocin determination but also for adulteration detection of saffron with water-soluble colorants. The method was applied to 260 samples of Spanish saffron, which came from the regions where saffron is an important crop, i. e., Castilla-La Mancha and Aragón. Spain is in the top group of saffron producers and Castilla-La Mancha is the largest saffron producing region in Spain. Four crocins and picrocrocin were ranked and the values used for differentiation according to origin. Only discriminant analysis could explain 100% of the variance by samples and location. The major discriminant variable was trans-crocin 4. 相似文献
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Chemical Detoxification of Aflatoxin-containing Copra 总被引:1,自引:0,他引:1
Aflatoxin-containing copra at moisture contents of 24% and 7% was effectively detoxified by ammonium hydroxide (> 97% and 89% reduction, respectively). Detoxification was accomplished in 5 days using 1.5% ammonium hydroxide (ammonia/copra); in 10 days using 1.0% and in 15 days using 0.5%. The initial aflatoxin B1 concentration of 500 ppb (9% moisture) was reduced to ≤ 20 ppb. Detoxification trials using a screw expeller showed 67% reduction in aflatoxin content of the oil with 1.0% ammonia. 相似文献
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CHAY B. PHAM R. R. DEL ROSARIO 《International Journal of Food Science & Technology》1983,18(2):163-170
Protein hydrolysate prepared from defatted soybean meal and coconut meal using acid hydrolysis under different conditions were analysed and subjected to sensory evaluation. Analysis of amino acid after hydrolysis showed a 10.32% reduction in the soybean product and a 31.93% reduction in coconut product. Chemical analyses showed similarities in pH, viscosity, salt content and reducing sugar between the hydrolysates and the commercial soy sauce sample. Both amino and total nitrogen and acidity were higher in the hydrolysate than the commercial sample.
Sensory evaluation showed that hydrolysed soybean products gave better scores in terms of colour, aroma, flavour and general acceptability than coconut products. Addition of soybean to coconut meal resulted in improved hydrolysed product. 相似文献
Sensory evaluation showed that hydrolysed soybean products gave better scores in terms of colour, aroma, flavour and general acceptability than coconut products. Addition of soybean to coconut meal resulted in improved hydrolysed product. 相似文献
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This study was conducted to determine the effects of temperature, time and concentration of acids on the hydrolysis of coconut and soybean meals. Using 6∼ hydrochloric acid (HCl), the complete hydrolysis of soybean meal was reached after 36 hr at 95°C, while it took only 24 hr to complete the process when 18 N sulphuric acid (H2 SO2 ) was used at the same temperature. Coconut protein exhibited some degree of resistance to hydrolysis. Using 10 N HC1 and 18 N H2 SO2 in two separate tests, it took 48 hr to complete hydrolysis at 95°C. Sulphuric acid caused a considerably greater decomposition of amino acids than HCl during longer periods of reaction with high acid concentration and temperature. Flavour development is a function of the free amino acids released which in turn is a function of acid concentration, reaction time and temperature. 相似文献
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SARA INÉS ROURA MARÍA DEL ROSARIO MOREIRA CARLOS ENRIQUE DEL VALLE 《Journal of food quality》2004,27(2):91-101
The shelf-life of fresh-like ready-to-use diced squash during storage for 16 days at 10–12C and 95% of relative humidity was investigated. The ascorbic acid (AA) content, moisture, soluble solid content, titratable acidity, pH, weight loss and microbiological counts were determined. At the end of storage, a 1.5% weight loss was observed. Water content did not show significant changes during storage. The soluble solids content and the Brix/titratable acidity ratios increased during storage, following a linear correlation. The evolution of AA content followed a 2° polynomial correlation, with a maximum between 7–9 days of storage and a final value of 17 mg AA/100 g of fresh weight. The total microbial count increased continuously throughout storage but showed an acceptable level until day 10. 相似文献
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WANQING CAO ROSARIO GERHARDT JOHN B. WACHTMAN Jr. 《Journal of the American Ceramic Society》1988,71(12):1108-1113
Porous silica gelled from colloidal silica and potassium silicate mixtures as developed by Shoup has been investigated. Various gels exhibit an average pore size from 50 to 250 nm and a porosity up to 85%. Dealkalization by solution leaching is found to depend on the average pore size and is easier for large pore sizes. A domain model has been proposed for the gel networks to account for the observation of both macropores and mesopores as measured by Hg porosimetry and N2 desorption, respectively. The pore coarsening observed during sintering is explained by the material transport from areas around interdomain pores to those around intradomain pores in order to minimize the total surface energy. 相似文献