Critical Review of Key Analytical Issues With Gelatins

Abstract

This chapter will focus on many of the common analytical techniques used to study the physicochemical properties of gelatin. These are the critical assays that are used to characterize the gelatin and are used by the industry to determine the quality and, therefore, the economical and practical value of these gelatins. With the current interest in obtaining gelatin from new sources, especially in the seafood/fish area, there is a greater need to be sure these tests are done in such a way that data can be compared between laboratories and across species. Because of gelatins' unique amino acid sequence and structure, some of the standard techniques have some interesting limitations. The goal of this chapter is to review these methods critically targeting both the relatively new investigator, who is unaware of some of the pitfalls when using these often considered routine tests, and at the same time, the advanced professional, who often overlooks some of these issues. For example, among the techniques that will be looked at, there are those for protein determination, where the absence of tryptophan and the presence of hydroxyproline (and a little hydroxylysine) may need to be taken into account. The determination of gelatin in the presence of other proteins and how this might affect the framing of gelatin yield will also be discussed. The difficulties of doing amino acid analysis correctly will be addressed. Some of the rapid and practical methods used by the industrial users of gelatin will be compared to those used in the laboratory, e.g., melting and setting point, viscosity and gel strength. The challenges of doing SDS-PAGE with a protein that is partially hydrolyzed will be covered along with a discussion on the use of Texture Profile Analysis for learning more about the gel properties of gelatin gels and gelatin-based products than what can be obtained from gel strength alone. So, this paper is dedicated to the improvement of the data presented in the scientific literature on gelatin. © 2013 by Nova Science Publishers, Inc. All rights reserved.