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Book Review |
Dean, College of Agriculture, California State Polytechnic University, Pomona
Dr. G. Mazza has produced an excellent volume on Functional Foods. To date, this is the most intelligent treatment of the topic. The editor has selected 26 internationally respected scientists to contribute 13 chapters to the book, providing an overview of functional foods.
Functional foods, designer foods and nutraceuticals refer to foods or food ingredients that provide nonnutritive physiological benefits that may enhance health. The market is driven by consumers’ demand—a need to find a means to optimize their health through foods and herbs in an effort to offset the cost of drugs and health care. Important to the approval of health claims is the necessity to identify the active component and generate enough scientific evidence to support the efficacy of the claim.
This book provides a comprehensive treatment of the physiological effects of foods and food components capable of promoting health and preventing or alleviating diseases. Chapter topics include very thorough discussions of oat ß-glucan, wheat bran, rice bran and oil, flaxseed, grapes, citrus products, vegetables, mustard, designer vegetable oils, amaranth, ginseng and echinacea, milk and dairy products and seafoods. Importantly, the chapters discuss the health potential of specific food components and the effects of processing on the activity. The book closes with a chapter on regulatory aspects of functional foods.
A lot of research has been done on the role of oat ß-glucan, a viscous soluble polysaccharide, which may reduce cholesterol in hypercholesterolemic patients, thereby reducing the risk of heart disease. Rolled oats, oat bran and other products have sufficient ß-glucan to provide the health benefit. Factors such as the amount of ß-glucan, solubility, molecular weight and structure affect health, but the impact of processing on these functions needs further examination. A clear understanding of the properties and mechanism of action of ß-glucan is needed to better design clinical trials.
Wheat bran contains insoluble fiber, which has been recognized for stimulating regularity and prevention of constipation by increasing fecal bulk. This physiologic effect is greater than for vegetables and 50% greater than for oat bran. From a broad range of animal and epidemiological studies, including clinical trials, consistent support for a preventive role in reducing the risk of colon cancer has been reported. Prevention of colon cancer remains controversial, but appears more effective with wheat bran than other types of fiber. Other phytochemicals in wheat may also have health benefits.
Rice kernels contain a high starch content surrounded by a hull and bran. The bran contains the highest level of nutrients and is extracted for oil, protein, fiber insoluble hemicellulose and smaller amounts of soluble fiber. Rice bran oil contains tocopherols, tocotrienols and oryzanols. All three compounds are good antioxidants. In addition, tocotrienols may lower HMG CoA reductase and serum cholesterol and may have anti-cancer activities. The oil contains high levels of palmitic, oleic and linoleic acids. Rice bran wax is similar to carnauba wax and may be more plentiful. The bran and the oil lowers serum LDL cholesterol. Selection of rice cultivars that have higher oil contents may be beneficial to producers and manufacturers. The endosperm of the rice kernel contains starch having a composition of about one-third amylose and two-thirds amylopectin. Commercially the starch granules are very fine and may be useful in other applications, such as a fat substitute, and rice components for sports beverages or energy bars.
Flaxseed is rich in a-linoleic acid (ALA) and good quality protein (similar to soy protein) and phytochemicals such as flavinoids, lignans and phenolic acids. The oil has been used as a paint hardener in Western countries and avoided for food use due to oxidation and polymerization. Flaxseed cultivars have been bred to decrease linoleic acid desaturase, lower ALA content to less than 3% and enrich the oil in oleic acid. Flaxseed hydrocolloid gum, mucilage, may have health benefits related to the viscous fiber.
A variety of biologically active constituents may contribute to the protective health effects of diets rich in fruits and vegetables. Grapes, grape juice and wine and grape seeds are all rich in phenolic compounds, particularly the flavonoids, which have been evaluated for their role in anticarcinogenic, antiatherogenic, anti-inflammatory, antimicrobial and antioxidant activities. Use of the component phenolics, such as resveratrol, ellagic acid and flavonoids, needs to be made in the development of new functional food products. A better understanding of the biological role of grape phenolics for their health benefits and for their safety when added to food systems remains. Citrus fruit, juices and by products contain vitamins C and E and carotenoids, which are involved, via the antioxidative properties of these nutrients, in preventing or delaying several degenerative diseases related to oxidative tissue damage, such as cancer, cardiovascular disease and cataracts. Several non-nutritive components, liminoids and flavonoids are recovered and seem to inhibit carcinogenesis by acting as blocking and/or suppressing agents. Many of these agents are value added to the industry, since they are recovered from skins and pulp which may normally be discarded.
Other plant sources of vegetables and herbs are examined in several of the remaining chapters such as Cruciferae, Allium, Mustard, Amarath, Quinoa, Ginseng, Echinacea and Sea Buckhorn. In addition, two chapters discuss functional activities of milk, other dairy products and seafood products. Using milk as the base, probiotic products have been developed to enhance the ecology of the colon. Enhanced concentrations of lactobacillus and bifidobacterium compete with and drive out undesirable organisms, thereby producing a positive environment for protection of the GI tract. Casein-based bioactive peptides have been discovered and are currently under detailed investigation. Other functional agents, especially omega-3 fatty acids, have positive effects on health. Fish protein has unique properties for reestablishing fibers, extrusion and formation of new protein textures. Thus, novel lipid and protein products may be created from underutilized aquatic species and the processing discard of the fish industry.
These are only a small portion of the topics covered in the text, including much more detail on processing of existing and new products. The book is well written and should benefit food scientists and food technologists, academic and industry researchers, nutritionists, biochemists, public health professionals and entrepreneurs who are designing and marketing new functional food products. It is an excellent book for discussion by graduate students and an educational experience for medical students.
Received February 1, 1999.
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