Lipid Oxidation (eBook)

Challenges in Food Systems

Amy S. Logan, Uwe Nienaber, Xiangqing (Shawn) Pan (Herausgeber)

eBook Download: PDF | EPUB

2015 | 1. Auflage
548 Seiten
Elsevier Science (Verlag)
978-0-9888565-1-6 (ISBN)

Infos

Lipid oxidation in food systems is one of the most important factors which affect food quality, nutrition, safety, color and consumers' acceptance. The control of lipid oxidation remains an ongoing challenge as most foods constitute very complex matrices. Lipids are mostly incorporated as emulsions, and chemical reactions occur at various interfaces throughout the food matrix. Recently, incorporation of healthy lipids into food systems to deliver the desired nutrients is becoming more popular in the food industry. Many food ingredients contain a vast array of components, many of them unknown or constituting diverse or undefined molecular structures making the need in the food industry to develop effective approaches to mitigate lipid oxidation in food systems. This book provides recent perspectives aimed at a better understanding of lipid oxidation mechanisms and strategies to improve the oxidative stability of food systems. - Five chapters on naturally-derived antioxidants that focus on applications within food systems - Contributors include an international group of leading researchers from academic, industrial, and governmental entities - Discusses the oxidative stability of enzymatically produced oils and fats - Provides overviews on the complexities of lipid oxidation mechanisms, and emulsion systems most suseptible to rapid lipid oxidation

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CHAPTER 2

Challenges in Analyzing Lipid Oxidation

Are One Product and One Sample Concentration Enough?

K.M. Schaich1,     1Dept. of Food Science, Rutgers University, 65 Dudley Rd., New Brunswick, NJ 08901-8520

Fundamental Requirements of Lipid Oxidation Analyses

Students learn about monitoring reactions in the context of straightforward reactions with fixed stable products that form in high concentrations; for example,

+B→C (2.1)

(2.1) or

+B→C+D (2.1a)

(2.1a)

This situation directly contrasts with lipid oxidation, which has multiple possible pathways that change with conditions and over time. In these reactions, products are actually intermediates that degrade or transform into other compounds, as shown in Fig. 1.2 of Chapter 1, and product yields are quite low; a total reaction of less than 1% renders foods inedible. Thus, lipid oxidation is generally considered to be the greatest analytical challenge in food science. Similar arguments could be made for cosmetics and many personal care products, as well as for biological tissues in which lipid oxidation and its effects are complex, even when total oxidation levels are low.

One question that persists in lipid oxidation analysis is which product is best to monitor? The answer is strongly influenced by the either quantitative or qualitative end goals of analyses. Industry rejects batches and makes decisions about formulations based on quantitation, which requires accuracy and reproducibility, and product class analysis (that is, for all hydroperoxides or all epoxides, regardless of structure) is usually adequate. In contrast, basic research seeks to elucidate reaction mechanisms, and oxidation sequences need as much quantitative and qualitative detail about individual products as possible. Oxygen consumption is often preferred for determining oxidation kinetics when starting from fresh products because it is independent of product transformation, but it cannot be used for spot analyses of products off the production line or storage shelf. For the latter, the question becomes, does one measure hydroperoxides because they form first (even though they decompose) or secondary products to detect hydroperoxide breakdown and because consumers can smell and taste them? Does a researcher analyze only volatiles because gas chromatographs are readily available, only non-volatile products because they remain in the product, or both? The picture of lipid oxidation that we construct depends on the analytical strategy used.

A wide variety of assays for various lipid oxidation products has been developed; many methods have been standardized, and more are used simply by following (and modifying) procedures published in research papers. Some of the most common assays for various lipid oxidation products are listed in Table 2.A. A number of excellent reviews and books have presented details of individual methods (McDonald & Mossoba, 1997; Shahidi, 1998; Dobarganes & Velasco, 2002; Yildiz et al., 2003; Kamal-Eldin & Pokorny, 2005). Therefore, it is not the goal of this chapter to provide protocols for analyses or to recommend specific assays. Rather, this chapter argues for new approaches and seeks to change how lipid oxidation analyses are viewed and used to attain more complete and accurate information. First and foremost, the author challenges readers to “think chemistry” in all lipid oxidation analyses, rather than seeing black boxes in which procedures are accepted and applied blindly; instead, they should look beyond peroxide values to track multiple products and attempt mass balance between products.

Table 2.A

Examples of Analytical Methods Used to Determine Oxidation in Lipids

Lipid Oxidation Product

Standard Method

Reference

Conjugated dienes

AOCS Th 1a-64, Ti 1a-64 AOCS Ch 5-91 cyclohexane

White, 1995; AOCS, 2011b, 2011c

various other methods

de Andrade et al., 2010 (review)

Hydroperoxides

Dobarganes & Velasco, 2002 (review)

Iodometric titration

AOCS 8b-90, JOCS 2-4 12-71 isooctane

JOCS, 2009; AOCS, 2011i

AOCS Cd 8-53; IUPAC 2.501 CHCl3

IUPAC, 1992a; AOCS, 2011h

AOAC 41.1.16

AOAC, 2000

Xylenol orange—direct

Jiang et al., 1990, 1991; Jiang et al., 1992; Wolff, 1994; Nourooz-Zadeh et al., 1995; Bou et al., 2008

Xylenol orange—PeroxySafe™

AOAC alternate method 030405

Osawa et al., 2007; Biomedicals, 2012

Xylenol orange—Pierce kit

Pierce, 2011

Ferrithiocyanate—direct

IDF Standard Method 74A:1991

Shantha & Decker, 1994; Mihaljevic et al., 1996

Ferrithiocyanate—Cayman kit

Cayman, 2011

Triphenyl phosphine

Nakamura & Maeda, 1991; Akasaka & Ohrui, 2000; Talpur et al., 2010; Gotoh et al., 2011

Fourier transform infrared spectroscopy

Van de Vort et al., 1994; Sedman et al., 1997; Guillen and Cabo, 2002; Yu et al., 2007

NMR

Hamalainen & Kamal-Eldin, 2005

RP-HPLC—234 nm

Bauer-Plank & Steenhorst-Slikkerveer, 2000

post-column reaction

Yang, 1992

Alcohols (hydroxylated products)

AOCS Cd 4-40, Cd 13-60, Tx 1a-66

AOCS, 2011d; 2011e; 2011f

GC-MS of TMS ether derivatives

Guido et al., 1993

Epoxides

HBr titration

AOCS Cd 9-57

Durbetaki, 1956; Maerker, 1965; AOCS, 2011g

4-(p-Nitrobenzyl)pyridine

Hammock et al., 1974; Agarwal et al., 1979

Diethyldithiocarbamate/HPLC

Dupard-Julien et al., 2007

Tetrafluorobenzenethiol/GC-MS

Newman & Hammock, 2001

NMR

Hamalainen & Kamal-Eldin, 2005

HPLC-MS

Sjovall et al., 2001

Fourier transform infrared spectroscopy

Patterson, 1954; Bomstein, 1958; George, 1975

Carbonyls (soluble)

Dinitrophenylhydrazones—optical

JOCS 2.5.4

White, 1995; JOCS, 1996

—HPLC

Seppanen & Csallany, 2001

—chemiluminescence

Townshend & Wheatley, 1998

Indole

Nagawade & Shinde, 2006

p-Anisidine—chemical

AOCS Cd 18-90; IUPAC 2.504

IUPAC, 1987; White, 1995; AOCS, 2011a

FTIR

Dubois, 1996

Infrared spectroscopy

Moya Moreno et al., 1999; Mobaraki & Hemmateenejad, 2011

NMR

Haywood et al., 1995; Moya Moreno et al., 1999; Hamalainen & Kamal-Eldin, 2005

Volatile products—gas chromatography

Christie, 1989

Static headspace

Przybylski & Eskin, 1995

Volatile products—gas chromatography

Solid phase microextraction...

Produkt-Details

• Erscheint lt. Verlag: 15.8.2015
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Biologie ► Biochemie
• Themenwelt: Naturwissenschaften ► Biologie ► Zellbiologie
• Themenwelt: Naturwissenschaften ► Chemie ► Analytische Chemie
• Themenwelt: Technik ► Lebensmitteltechnologie
• ISBN-10: 0-9888565-1-4 / 0988856514
• ISBN-13: 978-0-9888565-1-6 / 9780988856516