COLORIMETRIC CHARACTERIZATION OF EGG YOLK AND EGG YOLK PRODUCTS

Procedures are suggested for COLOR-EYE® evaluation of various yolk forms and products. Chromaticity coordinates derived from COLOR-EYE determinations and the calculated dominant wavelength (λ_d), excitation purity (P_e) and luminous reflectance (Y_CIE) values were also determined for each yolk form and product analyzed. Characteristics of aged yolks included reduced λ_d and P_e and an increase in Y_CIE values; the greatest effects were at the highest levels of pigmentation concentration. Luminous reflectance values were substantially lowered by the addition of sugar and subsequent frozen storage; all other calorimetric criteria were relatively unchanged. Yolk age effects were negligible for the calorimetric characterization of yolks incorporated into product forms. Mayonnaise products provided the most consistent COLOR-EYE readings. These data suggest the feasibility of utilizing the COLOR-EYE, or similar instrumentation, as an objective method for the color characterization of various yolk products. Numerous options are available for converting data into other desired instrumentation values and terminology.     

REFLECTANCE COLORIMETRIC EVALUATION OF EGG YOLK PIGMENTATION

Moderately pigmented yolks were diluted with pigment-free yolks to provide a wide range of samples with which to compare standard beta carotene equivalents with excitation purity and luminous reflectance values obtained with a reflectance calorimeter. Pigmented yolks were also mixed with a white diluent for reflectance colorimetric comparisons. Correlation coefficients of beta carotene equivalents with excitation purity and luminous reflectance values were +0.906 and −0.874, respectively. The regression line for luminous reflectance was linear and for excitation purity was curvilinear. The white diluent (1:l ratio) resulted in significant reduction of the tendency of excitation purity to plateau for deeply pigmented yolks.     

CLARIFICATION OF EGG YOLK SUSPENSION FOR THE PRODUCTION OF N-ACETYLNEURAMINIC ACID

Several filter aids were investigated in order to separate the hydrolyzed egg yolk suspension easily. λ-Carrageenan was found to be the most effective flocculant for the purpose. The addition of 1.67 g λ-carrageenan to 1 L of hydrolyzed egg yolk suspension was effective to get a clear supernatant. The ionic flocculation between the λ-carrageenan and the egg yolk lipoprotein was presumed. Using λ-carrageenan, N-acetylneuraminic acid containing in the hydrolyzed delipidated egg yolk was prepared. λ-Carrageenan did not adsorb to an anion exchange resin and could be separated completely from N-acetylneuraminic acid, when the filtrate treated with λ-carrageenan was applied on a column of the resin.     

饮料配方的设计及感观评定

饮料配方的设计一般采用正交试验法，因素和水平的确定根据所模仿对象的不同而不同；饮料的风味是所设计配方的根本。此外，还要充分考虑到人们的饮用习惯，生理需要和饮料的发展趋势；所设计的饮料配方的可行性运用模糊数学矩阵来评定。     

A COMPREHENSIVE EVALUATION OF EGG AND EGG REPLACERS ON THE PRODUCT QUALITY OF MUFFINS

ABSTRACT

Five muffin formulations, liquid whole egg, dry whole egg, and three commercial egg replacers, which partially replaced egg in the formulations, were evaluated to determine differences in product qualities caused by egg and egg replacers. The products were prepared following the same procedure and other ingredient compositions, except for egg or egg replacer used in the formulation. Physical product characteristics and sensory properties of the samples were evaluated. It was found that egg, as an ingredient in the muffin formulation, is critical to obtain expected product quality characteristics. None of the commercial egg replacers produced acceptable quality muffins at 100% replacement. Partial replacement of egg with commercial egg replacers changed product characteristics altering moisture retention, bulk volume, color, texture and flavor. Some of these differences, however, were not readily detected by the sensory panelists.

PRACTICAL APPLICATIONS

This study comprehensively evaluated the effects of egg and egg replacers on final product quality, when used in pilot‐scale muffin production. An array of tests were conducted on samples prepared according to respective ingredient manufacturers' recommendations – partially replacing egg with commercial egg replacers – to objectively evaluate the differences in quality and sensory attributes. The functionalities of each ingredient (egg replacer) in muffin formulations were interpreted based on the results obtained. The observations and results of this study would be important in selecting appropriate ingredients for muffin formulations to obtain desired product qualities.

     

INFLUENCE OF COMMERCIAL SHIPPING ON THE COLOR AND COMPOSITION OF APPLE JUICE CONCENTRATE1

Apple juice concentrate manufactured in Argentina was sampled before and after shipment to the USA and subjected to a number of color and compositional analyses. These included browning, haze, Hunter parameters, titratable acidity, hydroxymethylfurfural (HMF), and HPLC determination of sugars, nonvolatile acids, and chlorogenic acid. The primary objective was to determine those parameters which showed significant changes as a result of commercial transport. Browning significantly increased as did HMF and fumaric acid content. There was no evidence for sucrose inversion and there was no significant change in titratable acidity as a result of this 55 day commercial shipment.     

THE LIPIDS OF EGG YOLK. 5. Presence of Ceramide

SUMMARY —Ceramide (an N-acyl sphingosine) was isolated from egg yolk lipid and examined for composition of fatty acids and long-chain base constituents. Yolk ceramide was observed to contain sixteen fatty acids; C _24:0 (35.7%), C _22:0 (22.7%), C _23:0 (15.1%) and C _24:1 (13.5%) were predominant. The component long-chain bases were identified as sphingosine and dihydrosphingosine, the former being the major component (88.6%).     

CONTINUOUS PASTEURIZATION OF EGG YOLK: THERMOPHYSICAL PROPERTIES AND PROCESS SIMULATION

This article presents empirical correlations to predict the density, specific heat, thermal conductivity and rheological power–law parameters of liquid egg yolk over a temperature range compatible with its industrial thermal processing (0–61C). Moreover, a mathematical model for a pasteurizer that takes into account the spatial variation of the overall heat transfer coefficient throughout the plate heat exchanger is presented, as are two of its simplified forms. The obtained correlations of thermophysical properties are applied for the simulation of the egg yolk pasteurization, and the obtained temperature profiles are used for evaluating the extent of thermal inactivation. A detailed simulation example shows that there is a considerable deviation between the designed level of heat treatment and that this is predicted through process simulation. It is shown that a reliable mathematical model, combined with specialized thermophysical property correlations, provide a more accurate design of the pasteurization equipment that ensures effective inactivation, while preserving nutritional and sensorial characteristics.