Virginia Polytechnic Institute and State University

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he Antioxidant Function of Lutein in Controlling Photo-Oxidation of a Colloidal Beverage System

Mark Kline, a Master's student in VA Tech's Department of Food Science, recently defended his thesis. He graduated in December and is currently employed by MasterFoods as a Food Scientist in Product Development Line Extension. The following abstract is a summary of his research.

Functional sports beverages incorporating vitamins, minerals, proteins and phospholipids have been developed to focus on not only athletic performance but overall health and well-being. Due to the effects of light exposure, many vitamin-enriched beverages, including milk, have been placed in opaque or tinted packaging to reduce the formation of off-flavors and protect nutrients from oxidation. However, consumers prefer clear packaging where they can see the product. Incorporation of antioxidants, such as lutein, within the beverage matrices may reduce light-induced oxidation without sacrificing consumer visual appeal. This research was performed to: 1.) determine effect of lutein fortification on sensory quality degradation in a model colloidal beverage system (MCBS) when exposed to light under refrigerated storage (14 d, 4°C) 2.) determine stability of lutein and its effect on beverage system aroma when exposed to specific light wavelengths during accelerated room temperature storage (12 hr, 25°C).

Under refrigerated storage, sensory triangle and rank preference tests were used to determine the effect of lutein in controlling light oxidation of a beverage system with added protein and phospholipids. Fluorescent light-exposure (14 d) of the control beverage system led to a decline in sensory quality. Sensory quality also declined in the lutein-fortified beverage due to light-exposure. The light-exposed, lutein-fortified beverage was not significantly different from the light-protected control for two out of three replications giving positive implications towards the use of lutein for photo-protection. Overall however, panelists preferred beverages that were protected from light exposure. No specific preference towards either light-exposed beverages (control or lutein-fortified) may indicate lutein did not fully inhibit photo-chemical reactions leading to a decline in sensory quality.

Chemical analysis by gas chromatography (GC) with solid-phase microextraction (SPME) was used to support sensory analysis by determining odor-active components in the system. Concentration of limonene was significantly higher in the lutein-fortified beverage compared to the control beverage after 14 d light exposure. Hexanal concentration, however, was not closely correlated with sensory differences. Odor-active compounds not detected by gas chromatography with solid-phase microextraction may be involved in sensory degradation under 14 d fluorescent light conditions.

Under accelerated storage (12 hr, 25°C), high performance liquid chromatography (HPLC) and GC with SPME were used to determine effect of specific light wavelength exposure on quality and stability of fortified and control beverage systems. The most damaging wavelengths to lutein stability were UV (200-400 nm) and 463 nm wavelengths. Degradation of lutein at 463 nm was expected and can be attributed to lutein's absorption of blue light at 450 nm. Hexanal formation was highest in the control beverage when exposed to full spectrum light and specifically UV (200-400 nm) wavelengths. Hexanal was also formed in the lutein-fortified beverage under full spectrum light and UV (200-400 nm) wavelength but to a significantly lesser degree. Limonene degraded significantly under all treatment conditions, with the most occurring during full spectrum light exposure. Lutein-fortification did not effectively protect limonene from degradation under these conditions.

The results of this study suggest colloidal beverage systems with whey protein and phospholipids are negatively affected by light exposure. Susceptibility can be attributed to photo-oxidation of lipid, protein and flavor components. Lutein fortification exhibited a photo-protective effect by reducing hexanal formation under full spectrum light and UV (200-400 nm) wavelength exposure under accelerated storage, however not to a degree comparable to light-protection.

Lutein degradation was shown to be a problem in the light-exposed functional beverage. The extent of photo-protection may not be great enough to negate lutein degradation when fortifying beverage systems for health benefits. Consideration should be given to using photo-protective barrier packaging to preserve lutein for health benefits.

HOT TOPICS AND DAIRY ISSUES

European Union Cautious About Milking Cloned Cows

The FDA recently issued a statement that it hoped to draft regulations on milk and meat from cloned animals in the U.S. in the next few months. This statement prompted the European Dairy Association (EDA) announce that it has no plans to approve manufacture of dairy foods from cloned animals in the European Union. The EDA is hesitant to jump into a debate that remains highly emotional and bound up with fears over genetically modified foods. Scientifically, the FDA may be correct in stating that dairy products from cloned animals are safe, but the EDA feels that European consumers will find these type products unacceptable.

Consumer groups in the US have already lambasted FDA plans to approve milk and meat from cloned cattle, and the Center for Food Safety has called for a nationwide moratorium. A landmark study was completed at The University of Connecticut and published last year. The results, cited by the FDA, conclude that there is no difference in milk quality, including protein, fat, antibody and lactose content from cloned cows.

More large studies will be important to assess the effects and feasibility of using cloning technology in the dairy industry. Dairy farms have the dilemma of deciding if cloning's advantages to breeding outweigh the potential consumer storm in response to these practices. Some believe the potential for premature death and abnormalities in cloned animals means the technology doesn't yet make economic sense for dairy farms.

FDA scientists have repeatedly decided over the last four years that milk and meat from cloned animals is safe to consume. Their entry into the US food chain is likely at some stage.

Efforts by EU countries to prevent these products from entering the European common market will probably depend on the World Trade Organization's (WTO) interpretation of the precautionary principle, and on what the WTO sees as a “legitimate concern”. EU countries have already been forced to abandon a moratorium on genetically modified foods after the WTO ruled the ban was illegal.

Denmark is the only EU member with specific legislation governing farm animal cloning. EU guidance on the issue draws on a body of indirect regulations and directives, such as those addressing food safety and animal health.