摘要:

ABSTRACTEgg albumen was modified to improve water retention properties of the coagulated, frozen and thawed product. Albumen was found to contribute more to expressible moisture (%EM) of coagulated whole egg mixture than yolk. For frozen and nonfrozen treatments, albumen (pH gt; 9.5) reduced %EM in both the coagulated albumen and whole egg mixtures made with pH‐adjusted albumen. Succinylated albumen (≤0.2% g anhydridelg albumen) reduced %EM for frozen and nonfrozen treatments. Albumen at pH 10.5 and 11.0 required less time to attain an equivalent cook value than at pH 7.0,8.0,9.0, and 1

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03499.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTApparent viscosities of pH‐adjusted or succinylated raw egg albumen were measured at 10, 20, and 30°C using a Haake rotary viscometer. Viscosities decreased with increasing temperature. Rheological power law model parameters indicated that as pH approached 5–6 and 11, albumen became more Newtonian. Control albumen (pH 9.0) and succinylated albumen were pseudoplastic. Intrinsic viscosities of DH 9.0, 10.0, and 11.0 albumens were 0.083, 0.092, and 0.102 dl/g, respectively, and that of succinylated albumend (0, 0.1, 0.2, and 0.4% w/w) were 0.052, 0.147, 0.149, and 0.184 dl/g, respectively. Apparent viscosities of coagulated albumen, measured by capillary extrusion, increased with pH but did not change with succinylation. Yield forces and rigidity moduli of these gels increased with pH but not with succinylation l

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03500.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTA nondestructive method to quantitate the coagulation process has been developed and used to obtain kinetic data on the heat‐induced gelation of egg albumen. It involves continuous monitoring of the force exerted by the gel as coagulation takes place and requires only one sample to observe the total process. From the information on the maximum force exerted by the gel, rate constants, Z values, and activation energies were calculated. This approach was applied to evaluate other coagulation processes such as the enzymatic coagulation of milk and the gelation of gelatin by coolin

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03501.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe cotyledon structure of resting peanut (Arachis hypogaeaL. cv. Florunner) seed before and after hydraulic pressing was investigated with light and scanning electron microscopy. Observations were made of the appearance of cell walls and the major subcellular components: spherosomes (oil reserve bodies), aleurone grains and starch grains. Major findings include previously unreported cell wall damage and surface fissures that may be important to processors who express the oil from peanuts.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03502.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe pH influenced the viscosity of a model system of tomato product which consisted of citrus pectin and bovine serum albumin. The viscosity change was completely reversible depending on the pH. The same pH effect was observed in tomato products. Since the amino acid compositions of proteins suggest that the electrostatic property of water‐soluble protein fraction from tomato juice can be similar to that of bovine serum albumin, the comparison of pH effects indicates that pectin‐protein interaction may be involved in consistency of tomato products. Denaturation of protein may result in a decrease in the serum viscosity during process

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03503.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTSoluble and ionically bound peroxidases were extracted from green asparagus with 0.05M sodium phosphate (pH 7.0) and the same buffer containing 1.0M NaCl, respectively. The two forms of peroxidase have been purified 237 and 53 fold, respectively, through ammonium sulphate fractionation, and successive chromatography on Sephacryl S‐200 and ConA Sepharose 4B columns. Eleven isoenzymes with different pI values were detected from the soluble form using isoelectric focusing and eight from the ionically bound form. The two forms of perooxidase showed a similar optimum pH range of 4.2–5.0 using three kinds of hydrogen donor with different buffers. The optimum temperature of the two peroxidase forms at pH 4.5 was around 50°C. Heat inactivation of both forms at 70° and 90°C was observed to be bi

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03504.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTFour methods (absorbance at 280 nm; the Lowry method; the fluor‐escamine method, and the trinitrobenzenesulfonic acid method) for determining hydrolysis of milk proteins were compared. Each method was applied to the trichloracetic acid soluble fraction of milk protein, which had been digested with trypsin for various periods of time. Detectability was measured as the ratio between standard error of estimate and slope calculated from the linear regression analysis of Deming for cases when both variables were subject to error. Although it was nondimensional, the detectability thus calculated was simple and reliable for comparing assay methods which were based on different analytical principles. Detectability as well as the detection limit measured according to Schwerdtfeger showed that, of the methods compared, the fluorescamine method was most reliable and sensitiv

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03505.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTTo examine the levels of glycosylated vitamin B6 in 22 foods, each food was stirred for 2 hr at pH 6.8 and then incubated for 2 hr at pH 5.0 and 37°C with β‐glucosidase (60 units per g food). Vitamin B6 content of foods was measured microbiologically before and after enzyme treatment as well as with acid hydrolysis. Animal products contained no measurable amount of glycosylated B6. Grains and legumes generally had a high level of this bound form (6–57% of the total vitamin B6). Of the fruits analyzed, orange juice had the highest level of glycosylated vitamin B6 (47%). Among fresh vegetables studied, raw carrots had the highest level (51%). For broccoli and cauliflower, the glycosylated value was higher for the processed food as compared to the raw

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03506.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThese studies examined the bioavailability of iron in iron‐enriched breads. The test breads also contained added protein in the form of gluten, soy or nonfat dry milk. Bioavailability was assessed based on net hemoglobin synthesis in rats initially made iron deficient and then fed bread‐based diets containing 38.5 ppm iron (NRC requirement for rat, 35 ppm) and 3.75, 5.00, or 6.25 ppm copper (NRC requirement for rat, 5 ppm). More hemoglobin was synthesized on milk‐supplemented (83 mg/mg iron) and on soy‐supplemented (85 mg/mg iron) bread diets than on gluten‐supplemented (59 mg/mg iron) bread diets. Copper appeared to have no influence on hemoglobin regeneration or on hepatic iron accumulation under the conditions of this e

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03507.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ABSTRACTThe effects of 2.5, 4.5, 6.5, and 8.5 ppm dissolved free oxygen on volatile compounds formation and dissolved free oxygen disappearance in oils during storage were studied. The amount of compounds formed in oil containing 8.5 ppm was double that in oil containing 2.5 ppm oxygen. The rate of oxygen disappearance in oil containing 8.5 ppm was three times as fast as that in oil containing 2.5 ppm oxygen. The rates of dissolved oxygen disappearance and formation of volatile compounds were significantly different for the four levels of dissolved oxygen (P<0.05). As the initial oxygen concentration in oil increased, the rate of oxygen disappearance and the amount of compounds formed increased. The results indicate that the formation of volatile compounds in oil during storage can be minimized by lowering the oxygen content.

ISSN:0022-1147    

DOI:10.1111/j.1365-2621.1983.tb03508.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY