Standard test may miss food ingredients that cause milk allergy

Joseph L. Baumert, Ph.D., who headed the study, explained that thermal and non-thermal processing of foods can change the proteins responsible for milk allergy in ways that make the proteins harder to detect using the standard test, termed the enzyme-linked immunosorbent assay (ELISA). Processing, however, may still leave the milk proteins capable of causing itchy skin, runny eyes, wheezing and other sometimes more-serious symptoms of milk allergy, despite the inability to detect the milk residue.

"The results of these studies could be utilized by commercial ELISA kit manufacturers to aid in improving ELISAs for detection of milk residue in processed food products. These improved tests can be adopted by the food industry, if necessary, to allow for reliable detection of milk residue regardless of the type of processing that is used," he said. "These improvements should not result in commercial tests that are more expensive or difficult for food processors to use."

Food processors use the ELISA to assure that processed foods that do not contain milk and processing equipment in facilities that process milk products are free of milk allergens, the substances that can trigger milk allergy.

Milk allergy is not the same as lactose intolerance, a condition in which people lack adequate amounts of the enzyme needed to digest lactose, the main sugar in milk. Lactose intolerance involves the digestive system, with symptoms like bloating, stomach cramps and diarrhea, after consuming milk or milk products. Milk allergy affects the immune system and can cause swelling of the throat, which makes it difficult to breath, and other symptoms that require immediate medical help.

Baumert explained that manufacturers and food-safety agencies use ELISAs to ensure that food-processing equipment and finished products are free of allergens or labeled with appropriate warnings. ELISAs are one of the most widely used diagnostic tests in the world today, a mainstay in everything from diagnosing pregnancy and detecting the AIDS virus in human blood to diagnosing a range of other diseases in plants and animals. The tests leverage the amazing ability of antibodies, proteins formed by the body's immune system, to attach to and mark for destruction bacteria, viruses and other foreign substances. An ELISA kit for milk proteins contains antibodies that bind to milk proteins that may be in a finished food product or on the surface of shared manufacturing equipment. If a sample taken from a finished product or from the surface of food-processing equipment contains milk residue, a color change will occur in the test, indicating a positive result for contamination with milk proteins.

Baumert, who is with the University of Nebraska-Lincoln, explained that heating and other processing of foods can make milk proteins aggregate together so it is difficult to get the milk proteins into solution, which enables them to be detected by the antibodies in ELISAs. The clumping, however, does not necessarily destroy the protein's ability to trigger an allergic reaction in sensitive people. Clumped-together proteins also would be likely to maintain their potency once they reached the human body, he added. Heating and other processing can also alter the structure of the protein, which can affect the ability of the antibody to bind to the milk proteins. Alteration in the protein structure does not necessarily mean that the milk proteins become non-allergenic for the majority of milk-allergic individuals.

His team studied and documented how ELISAs perform on several measures of accuracy when milk proteins undergo changes in foods that are boiled, baked, fried or heated in other ways. The results could help the food-processing industry and ELISA manufacturers make changes that better protect consumers with milk allergies, he said, noting that other scientists are doing similar research on foods that contain eggs and peanuts — both common causes of food allergy.

More information:
Abstract
Commercial enzyme-linked immunosorbent assays (ELISAs) are commonly used by food industry for validating removal of allergenic residue from food contact surfaces and detection of allergenic residue in finished products. ELISAs are the method of choice due to their specificity, sensitivity, and ease of use in an industrial setting, however, limited validation of ELISA kits has been conducted on food matrices that have undergone thermal processing. This is important to note when selecting a commercial milk ELISA for monitoring allergenic residues as several variations in formats (qualitative and quantitative assays), specificity (detection of total milk protein, casein, or beta-lactoglobulin), sensitivity, and reporting units (NFDM, skim milk powder, casein, beta-lactoglobulin) exist. Milk proteins can be differentially affected by thermal processing thus limiting detection and affecting overall risk-assessment decisions. The effects of common processing techniques (boiling, baking, frying, retorting, and UHT) on detection of milk residue using commercial ELISAs will be discussed.

Provided by American Chemical Society (news : web)

Seaweed as a rich new source of heart-healthy food ingredients

In an article that may bring smiles to the faces of vegetarians who consume no dairy products and vegans, who consume no animal-based foods, scientists have identified seaweed as a rich new potential source of heart-healthy food ingredients. Seaweed and other "macroalgae" could rival milk products as sources of these so-called "bioactive peptides," they conclude in an article in ACS's Journal of Agricultural and Food Chemistry.

Maria Hayes and colleagues Ciarán Fitzgerald, Eimear Gallagher and Deniz Tasdemir note increased interest in using bioactive peptides, now obtained mainly from milk products, as ingredients in so-called functional foods. Those foods not only provide nutrition, but have a medicine-like effect in treating or preventing certain diseases. Seaweeds are a rich but neglected alternative source, they state, noting that people in East Asian and other cultures have eaten seaweed for centuries: Nori in Japan, dulse in coastal Europe, and limu palahalaha in native Hawaiian cuisine.

Their review of almost 100 scientific studies concluded that that some seaweed proteins work just like the bioactive peptides in milk products to reduce blood pressure almost like the popular ACE inhibitor drugs. "The variety of macroalga species and the environments in which they are found and their ease of cultivation make macroalgae a relatively untapped source of new bioactive compounds, and more efforts are needed to fully exploit their potential for use and delivery to consumers in food products," Hayes and her colleagues conclude.

More information: “Heart Health Peptides from Macroalgae and Their Potential Use in Functional Foods” J. Agric. Food Chem., 2011, 59 (13), pp 6829–6836 DOI: 10.1021/jf201114d

Abstract
Macroalgae have for centuries been consumed whole among the East Asian populations of China, Korea, and Japan. Due to the environment in which they grow, macroalgae produce unique and interesting biologically active compounds. Protein can account for up to 47% of the dry weight of macroalgae depending on species and time of cultivation and harvest. Peptides derived from marcoalgae are proven to have hypotensive effects in the human circulatory system. Hypertension is one of the major, yet controllable, risk factors in cardiovascular disease (CVD). CVD is the main cause of death in Europe, accounting for over 4.3 million deaths each year. In the United States it affects one in three individuals. Hypotensive peptides derived from marine and other sources have already been incorporated into functional foods such as beverages and soups. The purpose of this review is to highlight the potential of heart health peptides from macroalgae and to discuss the feasibility of expanding the variety of foods these peptides may be used in.

Provided by American Chemical Society (news : web)

Creating the perfect Bloody Mary: Good chemistry of fresh ingredients

After tackling the chemistry of coffee, tea, fruit juices, soda pop, beer, wine and other alcoholic beverages, why not take on the ultimate challenge, the Mount Everest of cocktails, what may be the most chemically complex cocktail in the world, the Bloody Mary? And in this the International Year of Chemistry (IYC), why not include its global offspring, the International Mary?

Those challenges underpin a presentation today reviewing the Bloody Mary's composition and the taste sensations created by those ingredients at the 241st National Meeting & Exposition of the American Chemical Society (ACS), being held here this week.

"It's a very complicated drink," said Neil C. Da Costa, Ph.D., a expert on the chemical analysis of flavors at International Flavors & Fragrances, Inc., Union Beach, N.J. "The Bloody Mary has been called the world's most complex cocktail, and from the standpoint of flavor chemistry, you've got a blend of hundreds of flavor compounds that act on the taste senses. It covers almost the entire range of human taste sensations — sweet, salty, sour and umami or savory— but not bitter."

Da Costa said those flavors originate in the basic ingredients in the traditional Bloody Mary, which by one account originated in a Paris bar in the 1930's. Stories link the name to various historical figures, especially Queen Mary I of England, noted for her bloody repression of religious dissenters. The ingredients include tomato juice, Worcestershire and Tabasco sauce, fresh lemon or lime juice, horseradish, black pepper, and celery salt. Shaken with ice or served over ice, it is often garnished with celery and a lemon wedge.

"Most of the ingredients have been analyzed for their key flavor volatiles, the chemicals that can evaporate from the glass and produce the aroma," Da Costa explained. "Similarly for the non-volatiles, which are the chemicals that stay in the liquid and contribute toward the flavor there. My presentation reviews the composition of these ingredients and highlights the key components and their sensory attributes."

Some of the ingredients have been linked with beneficial health effects, Da Costa, noted, citing the rich source of lycopene, for instance, in the tomato juice; horseradish with its allyl isothiocyanate, which can be effective at lower concentrations; other phytochemicals in lemon; and even the alcohol in vodka, which some studies suggest can be beneficial when taken occasionally in small amounts.

Does Da Costa's research provide any insights for making a good Bloody Mary? He cites several:
Make it fresh. Chemically, the Bloody Mary is a "highly unstable" concoction, and the quality tends to deteriorate quickly.
Ice it up. Serving Bloody Marys on ice helps to slow down the chemical reactions involving acids in tomato juice and other ingredients that degrade the taste.
Mind your mixes. If you use a cocktail mix, add some fresh ingredients to enhance the flavor and aroma.
Splurge on the juice. Tomato juice makes up most of the Bloody Mary's volume, so use high quality juice that has a deep, rich flavor.
Economize on the vodka. The intense, spicy flavor of a Bloody Mary masks the vodka, and using premium vodka makes little sense.In the spirit of the IYC, Da Costa discussed the variations on the Bloody Mary consumed in other parts of the world. These "International Marys" include Denmark's Danish Mary; the Highland Mary (a.k.a. the Bloody Scotsman); the Russian Mary; the Bloody Geisha (yes, that's sake instead of vodka); the Bloody Maureen (replace vodka with Guinness); and the Bloody Molly (Irish whiskey replaces vodka).

Provided by American Chemical Society (news : web)

Creating the perfect Bloody Mary: Good chemistry of fresh ingredients

After tackling the chemistry of coffee, tea, fruit juices, soda pop, beer, wine and other alcoholic beverages, why not take on the ultimate challenge, the Mount Everest of cocktails, what may be the most chemically complex cocktail in the world, the Bloody Mary? And in this the International Year of Chemistry (IYC), why not include its global offspring, the International Mary?

Those challenges underpin a presentation on March 29 reviewing the Bloody Mary's composition and the taste sensations created by those ingredients at the 241st National Meeting & Exposition of the American Chemical Society (ACS), being in Anaheim, California.

"It's a very complicated drink," said Neil C. Da Costa, Ph.D., a expert on the chemical analysis of flavors at International Flavors & Fragrances, Inc., Union Beach, N.J. "The Bloody Mary has been called the world's most complex cocktail, and from the standpoint of flavor chemistry, you've got a blend of hundreds of flavor compounds that act on the taste senses. It covers almost the entire range of human taste sensations -- sweet, salty, sour and umami or savory -- but not bitter."

Da Costa said those flavors originate in the basic ingredients in the traditional Bloody Mary, which by one account originated in a Paris bar in the 1930's. Stories link the name to various historical figures, especially Queen Mary I of England, noted for her bloody repression of religious dissenters. The ingredients include tomato juice, Worcestershire and Tabasco sauce, fresh lemon or lime juice, horseradish, black pepper, and celery salt. Shaken with ice or served over ice, it is often garnished with celery and a lemon wedge.

"Most of the ingredients have been analyzed for their key flavor volatiles, the chemicals that can evaporate from the glass and produce the aroma," Da Costa explained. "Similarly for the non-volatiles, which are the chemicals that stay in the liquid and contribute toward the flavor there. My presentation reviews the composition of these ingredients and highlights the key components and their sensory attributes."

Some of the ingredients have been linked with beneficial health effects, Da Costa, noted, citing the rich source of lycopene, for instance, in the tomato juice; horseradish with its allyl isothiocyanate, which can be effective at lower concentrations; other phytochemicals in lemon; and even the alcohol in vodka, which some studies suggest can be beneficial when taken occasionally in small amounts.

Does Da Costa's research provide any insights for making a good Bloody Mary? He cites several:

Make it fresh. Chemically, the Bloody Mary is a "highly unstable" concoction, and the quality tends to deteriorate quickly.Ice it up. Serving Bloody Marys on ice helps to slow down the chemical reactions involving acids in tomato juice and other ingredients that degrade the taste.Mind your mixes. If you use a cocktail mix, add some fresh ingredients to enhance the flavor and aroma.Splurge on the juice. Tomato juice makes up most of the Bloody Mary's volume, so use high quality juice that has a deep, rich flavor.Economize on the vodka. The intense, spicy flavor of a Bloody Mary masks the vodka, and using premium vodka makes little sense.

In the spirit of the IYC, Da Costa discussed the variations on the Bloody Mary consumed in other parts of the world. These "International Marys" include Denmark's Danish Mary; the Highland Mary (a.k.a. the Bloody Scotsman); the Russian Mary; the Bloody Geisha (yes, that's sake instead of vodka); the Bloody Maureen (replace vodka with Guinness); and the Bloody Molly (Irish whiskey replaces vodka).

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by American Chemical Society.