Critical Reviews in Food Science and Nutrition

Michalski, Marie‐Caroline; Desobry, Stéphane; Hardy, Joël

doi: 10.1080/10408399709527791pmid: 9408728

Abstract This article reviews the various theories of adhesion mechanisms and, more specifically, studies concerning foodstuffs adhesion to industrial equipment and packaging surfaces. Adhesion is governed by mechanical interlocking, wetting, electrostatic and chemical forces, and diffusion. Direct conclusions about the validity of one of these theories were seldom made in the empirical studies reviewed. The different food adhesion determination methods were detailed: direct observations, evaluations (weighting, UV absorbance, and adhesive loss), adhesion strength measurements, and indirect measurements via the wetting theory (tilted plane method, contact angle, and surface tension). The importance of proteins, product rheological properties, solid surface rugosity, and wetting phenomena in many adhesion cases is highlighted. Conclusions were made that fundamental mechanisms of food‐contact surfaces interactions still need to be investigated to improve understanding in the science of food materials.

Granado, Fernando; Olmedilla, Begoña; Blanco, Inmaculada; Gil‐Martinez, Enrique; Rojas‐Hidalgo, Enrique; Erdman, John W.

doi: 10.1080/10408399709527792pmid: 9408729

Abstract The availability of reliable information on food composition is essential both for the evaluation of diet and for nutritional research to relate diet to health or disease. In this article, we compare the total and individual carotenoid contents and the retinol equivalents in fruits and vegetables reported in several food composition tables and HPLC studies. The impact of the variability in carotenoid intake was evaluated on the basis of Spanish National Consumption Statistics and on the values for a standard diet. We identify, from a user's point of view, errors concerning identification of the items and the terms used to refer to the compounds. Food composition tables overestimate (by 2 to 48%) the retinol equivalent intake, whereas they underestimate (by 30 to 50%) the total carotenoid intake according to HPLC data. We study the effect of these main sources of error, their impact on dietary assessment and on the classification of relevant contributors, and the possible consequences with respect to proper diet in terms of nutritional assessment and epidemiological studies. Given the different dietary habits among populations and the fact that certain items may be over‐ or underestimated in databases, the use of a single database may be misleading as to the rate of carotenoid consumption and the “true” nutrient intake in a given population, thus weakening the reliability of the study and resulting in erroneous conclusions.

Paul, S.; Mittal, G. S.; Chinnan, M. S.

doi: 10.1080/10408399709527793pmid: 9408730

Abstract During frying, the degradation of oil produces harmful compounds. Improper monitoring of oil‐discard times in restaurants either risks the public health or causes financial losses to industries. Measuring the oil quality is a complex problem and an online sensor is needed. The process of frying reviewed includes moisture, heat and fat/oil transfer, crust formation and various structural, textural and chemical changes in the product, and degradation of frying medium. Some of the European nations and the U.S. have specific regulations against the use of deteriorated frying oils. Due to the absence of a suitable online frying oil quality sensor for restaurant situations, it is difficult to implement any regulation against the use of deteriorated frying oil. Based on various regulations, a model regulation to increase the safety and quality of fried foods is discussed. Background and requirements for developing an online sensor to measure frying oil quality are discussed. Other related areas reviewed in this article are factors affecting oil penetration and absorption by the food, surfactant theory of frying, analytical indices, quick tests and acceptability of frying oil.

Imafidon, Gilbert Idolo; Farkye, Nana Y.; Spanier, Arthur M.

doi: 10.1080/10408399709527794pmid: 9408731

Abstract This review covers selected methods of isolation and purification of mainly αs‐casein, β‐casein, κ‐casein, β‐lactoglobulin, and α‐lactalbumin. Selected methods of alteration of some functional groups of these proteins also were reviewed. Isolation and purification of milk proteins per se are methods of modifying the individual milk proteins. Gram quantities of these proteins can now be purified in a relatively short time using ion‐exchange resins. Due to the prominent use of non‐food‐grade reagents in the procedures for preparation of these milk proteins, individual proteins are not maximally utilized for the manufacture of food/feed and pharmaceutical products. Therefore, intensive research efforts are needed to obviate the problems associated with underutilization of milk proteins.