Showing papers in "Critical Reviews in Food Science and Nutrition in 2001"

Gelatin: A Valuable Protein for Food and Pharmaceutical Industries: Review

Abstract: Many works have appeared in various scientifically reputable journals and publications worldwide that seem to have made potential or satisfactory contribution to our knowledge on the functions and utilization of gelatin - an important source of animal protein. Irrespective of these worldwide publications, room still exists for more work to be done to fully understand the utilization, chemical, biological, physical and functional properties of gelatin. Chemical and enzymatic modifications as well as biological studies should be undertaken with accuracy to be able to extend the utilization of gelatin in food and pharmaceuticals.

Advances in the development of functional foods from buckwheat.

Abstract: Buckwheat originated in North or East Asia and is widely adapted in North America. It has been grown since at least 1000 BC in China. It has very strong adaptability to adverse environments with a very short growing span. Many varieties are growing around the world, but mainly in the north hemisphere. Currently the most common buckwheat spice is Fagopyrum esculentum Moench (common buckwheat or sweet buckwheat), while Fagopyrum tartaricum is also available in some mountainous regions. Many nutraceutical compounds exist in buckwheat seeds and other tissues. Buckwheat has been used and will be better used as an important raw material for functional food production. In this review we focus on works related to the development of functional foods from common buckwheat, Fagopyrum esculentum Moench. A lot of research has be conducted in the functionalities and properties of buckwheat proteins, flavonoids, flavones, phytosterols, thiamin-binding proteins, and other rare compounds in buckwheat seeds. Buckwheat proteins have unique amino acid composition with special biological activities of cholesterol-lowering effects, antihypertensition effects, and improving the constipation and obisity conditions by acting similar as to dietary fiber and interrupting the in vivo metabolisms. The trypsin inhibitors isolated from buckwheat seeds are heat stable and can cause poor digestion if they are not suitably cooked before consumption. The allergenic proteins existing in the buckwheat seeds and their derivatives were reviewed with respect to their chemical and biochemical characteristics as well as the physiological reactions after digestion. Some possible mechanisms involved in these effects are discussed in this review. Experiments, both with animal models and with human beings, revealed that buckwheat flour can improve diabetes, obesity, hypertension, hypercholesterolemia and constipation. Methods to exploit buckwheat seeds and flour to produce highly effective nutraceuticals are also reviewed.

Inulin and Oligofructose as Dietary Fiber: A Review of the Evidence

Abstract: This critical review article examines the composition and source of inulin and oligofructose, the physiological effects of their consumption, and how these materials relate to the concept of dietary fiber. Inulin and oligofructose are fructans extracted on a commercial basis from the chicory root. Inulin has been defined as a polydisperse carbohydrate material consisting mainly, if not exclusively, of beta (2-1) fructosyl-fructose links ranging from 2 to 60 units long. Native chicory inulin has an average degree of polymerization (DP) of 10 to 20, whereas oligofructose contains chains of DP 2 to 10, with an average DP of 4. While a universally accepted definition for dietary fiber does not exist, it is generally agreed that this term includes saccharides (+ lignin) that are not hydrolyzed or absorbed in the upper part of the gastrointestinal tract. These materials reach the colon, where they may be totally fermented, partially fermented, or remain unfermented. In addition, fibers contribute to fecal bulking. Inulin and oligofructose are not digested in the upper part of the gastrointestinal tract or are they absorbed and metabolized in the glycolytic pathway, or directly stored as glycogen like 'sugars' or starches. None of the molecules of fructose and glucose that form inulin and oligofructose appear in the portal blood. These materials are quantitatively fermented by the microflora of the colon; further, it has been demonstrated that this fermentation leads to the selective stimulation of the growth of the bifidobacteria population. After reviewing their chemistry, origin, and physiological effects, it is the opinion of the authors that inulin and oligofructose are dietary fiber. They share the basic common characteristics of dietary fibers, that is, saccharides of plant origin, resistance to digestion and absorption in the small intestine, and fermentation in the colon to produce short-chain fatty acids that are absorbed and metabolized in various parts of the body. Moreover, this fermentation induces a bulking effect.

Chemical Composition and Potential Health Effects of Prunes: A Functional Food?

Abstract: Prunes are dried plums, fruits of Prunus domestica L., cultivated and propagated since ancient times. Most dried prunes are produced from cultivar d'Agen, especially in California and France, where the cultivar originated. After harvest, prune-making plums are dehydrated in hot air at 85 to 90 degrees C for 18 h, then further processed into prune juice, puree, or other prune products. This extensive literature review summarizes the current knowledge of chemical composition of prunes and their biological effects on human health. Because of their sweet flavor and well-known mild laxative effect, prunes are considered to be an epitome of functional foods, but the understanding of their mode of action is still unclear. Dried prunes contain approximately 6.1 g of dietary fiber per 100 g, while prune juice is devoid of fiber due to filtration before bottling. The laxative action of both prune and prune juice could be explained by their high sorbitol content (14.7 and 6.1 g/100 g, respectively). Prunes are good source of energy in the form of simple sugars, but do not mediate a rapid rise in blood sugar concentration, possibly because of high fiber, fructose, and sorbitol content. Prunes contain large amounts of phenolic compounds (184 mg/100 g), mainly as neochlorogenic and chlorogenic acids, which may aid in the laxative action and delay glucose absorption. Phenolic compounds in prunes had been found to inhibit human LDL oxidation in vitro, and thus might serve as preventive agents against chronic diseases, such as heart disease and cancer. Additionally, high potassium content of prunes (745 mg/100 g) might be beneficial for cardiovascular health. Dried prunes are an important source of boron, which is postulated to play a role in prevention of osteoporosis. A serving of prunes (100 g) fulfills the daily requirement for boron (2 to 3 mg). More research is needed to assess the levels of carotenoids and other phytochemicals present in prunes to ensure correct labeling and accuracy of food composition tables in order to support dietary recommendations or health claims.

Agricultural produces: synopsis of employed quality control methods for the authentication of foods and application of chemometrics for the classification of foods according to their variety or geographical origin.

Abstract: A review of quality control methods and applications of multivariate statistical techniques on the authentication and classification of agricultural products is presented. The products reported within the frame of this article were vegetables, fruits, juices, jams, wines, cereals, bakery products, oils, tea, coffee, honey, sugar-syrups, salad dressings, and gums. The perspective of multivariate statistics as a promising tool to authenticate and classify these food products according to their geographical origin or variety was demonstrated. Several representative figures and informative synoptical tables for agricultural food products were provided both for the quality control methods employed and the multivariate analyses implemented.

Alternative treatments for weight loss: a critical review.

Abstract: "Nontraditional" or "alternative" treatments are extremely popular, especially with respect to obesity and body composition. Although such treatments are widely used, it is not clear that these are supported by the existing data in the peer-reviewed literature. Herein, we review the data on 18 methods/products advocated as potential anti-obesity/fat-reducing agents. We have found that none have been convincingly demonstrated to be safe and effective in two or more peer-reviewed publications of randomized double-blind placebo-controlled trials conducted by at least two independent laboratories. Nevertheless, some have plausible mechanisms of action and encouraging preliminary data that are sufficiently provocative to merit further research.

A review of factors affecting fat absorption in hot chips

Abstract: Consumption of hot chips is a convenience food in most countries. Unfortunately, these are high in fat and contribute to fat-related diseases in societies with a high fat consumption. There is substantial scope through best-practice deep-frying techniques for producing lower fat, high-quality chips. From a review of the literature, the main factors associated with a lower-fat content of chips are thick (>12 mm), straight cut chips; cryogenic freezing methods; low moisture content of potatoes (specific gravity >1.1); frying fat: chip volume ratio of 6:1; frying at optimal temperature (180 to 185 degrees C) during cooking and turning the temperature down (approximately 140 degrees C) and covering the vats during slack periods; vigorously shaking the basket and hanging it over the deep fryer to drain after frying; maintaining the quality of the frying fat by regularly skimming the cracklings, filtering the fat, and topping up the fryer with fresh fat; keeping the fat turnover <5 days; regular cleaning of frying equipment. It is important that all deep frying operators are adequately trained in these techniques. It is also important that the frying medium is low in saturated and trans fatty acids (<20%) because of their effects on blood lipids and low in linolenic acid (<3%) because it is readily degraded. The widespread implementation of best-practice deep-frying would reduce fat content of hot chips and thus lower overall fat consumption.

New analytical techniques in food science.

Abstract: In this review, some of the latest analytical techniques that are being used for the study and characterization of food are examined. This work intends to provide an updated overview (including works published up to June 1999) on the principal applications of such techniques together with their main advantages and drawbacks in food analysis. Some future developments of these systems and their foreseeable application in food characterization are also discussed. The reviewed techniques are those based on spectroscopic, biological, separation, and electrochemical procedures. Moreover, some relevant facts on new systems for sample preparation and on-line couplings are also given.

Delay of natural bone loss by higher intakes of specific minerals and vitamins.

Abstract: For early prevention or inhibition of postmenopausal and age-related bone loss, nutritional interventions might be a first choice. For some vitamins and minerals an important role in bone metabolism is known or suggested. Calcium and vitamin D support bone mineral density and are basic components in most preventive strategies. Magnesium is involved in a number of activities supporting bone strength, preservation, and remodeling. Fluorine and strontium have bone-forming effects. However, high amounts of both elements may reduce bone strength. Boron is especially effective in case of vitamin D, magnesium, and potassium deficiency. Vitamin K is essential for the activation of osteocalcin. Vitamin C is an important stimulus for osteoblast-derived proteins. Increasing the recommended amounts (US RDA 1989), adequate intakes (US DRI 1997), or assumed normal intakes of mentioned food components may lead to a considerable reduction or even prevention of bone loss, especially in late postmenopausal women and the elderly.

Thermal and physical properties of bakery products.

Abstract: This article reviews the measurement techniques, prediction models, and data on thermo-physical properties of bakery products: specific heat, thermal conductivity, thermal diffusivity, and density. Over the last decade, investigation has focused more on thermo-physical properties of nonbread bakery products. Both commonly used and new measurement techniques for thermo-physical properties reported in the publication are presented with directions for their proper use. Data and prediction models are tabulated for the range of moisture content and temperature of the bakery products.

Commercial weight loss products and programs: what consumers stand to gain and lose. A public conference on the information consumers need to evaluate weight loss products and programs.

Abstract: A Public Conference on the Information Consumers Need to Evaluate Weight Loss Products and Programs REPORT OF THE PRESIDING PANEL This is the Presiding Panel's report of the conference proceedings. The views expressed herein by individual government participants do not necessarily reflect the views of their respective government agencies.

A Review on Grain and Nut Deterioration and Design of the Dryers for Safe Storage with Special Reference to Turkish Hazelnuts

Abstract: Turkey produces about 80% of the total hazelnut crop of the world. About 75% of the production are exported. In Turkey hazelnuts are traditionally sun dried, and may be subject to mold growth and subsequent mycotoxin formation due to prolonged drying time under humid and rainy weather conditions. Drying hazelnuts in a reasonable time after harvest is necessary for mycotoxin-free, high-quality products. In general, nuts and cereals contaminated by the toxins pose a potential hazard not only to the people of the producer countries, but also to people of the importing countries, if they should be regarded as safe by inefficient sampling plans, therefore preventing toxin formation actually benefits very large populations. Deterioration and health hazards associated with toxin contaminated hazelnuts and other nuts and cereals have similar causes and consequences; therefore, deterioration of the nuts and cereals in storage has been reviewed by considering as many grains and nuts as possible, then special reference was made to hazelnuts. Proper preharvest practices followed by proper drying and safe storage reduces the hazards associated with contamination by the toxins. This article reviews the pre- and post-harvest practices, and the grain- and nut-drying systems required for toxin-free products. Because drying is the major unit operation involving this process, the drying systems and the mathematical models required for their design is also discussed.

Principles and applications of luminescence spectroscopy.

Abstract: Advances in instrumentation during the last decade as well as the ease with which the technology could be adapted to a wide variety of assay platforms has truly made luminescence spectroscopy the analytical method of choice in several diverse disciplines of life sciences. The primary reasons for its growing popularity are twofold: the use of nonisotopic labels and its exquisite sensitivity. Analyte concentrations as low as 10(-10) to 10(-12) M can be easily detected, while luminometry can detect biological events at concentrations as low as 10(-18) M. This is in contrast to absorption and NMR spectroscopic techniques, which require, respectively, 10(-8) M and 10(-5) M concentrations of the compound of interest. Furthermore, in several variations of this technology, the measurement itself can be nondestructive and noninvasive. Despite the fact that luminescence spectroscopic techniques provide some of the most sensitive and selective analytical methods, they have not yet been widely used in both basic and applied food research. The only exception to this is the growing popularity of the commercially available ATP bioluminescence kits used routinely for monitoring the cleanliness of work surfaces in the food industry. This review describes some of the relevant basic aspects of luminescence, several popular variations of this technology, and their potential uses in food research.

Guidance for the clinical evaluation of weight-control drugs.

Abstract: The FDA published Good Guidance Practices in February 1997. This guidance was developed and issued prior to that date.

Special issue: The health effects of tea and tea components

Abstract: Report of an International Workshop organized by the ILSI International Subcommittee on the Health Effects of Tea Components, November 17-18 1999, Washington, DC, USA

Issues in the Substantiation Process of Health Claims

Abstract: Attempts are being made at the international level within the framework of the Codex Alimentarius to establish guidelines for health claims. An important issue that has to be addressed is the process of substantiating any health claim. Previous papers have addressed aspects relating to the development and regulatory control of functional foods and certain issues relating to claims. This paper addresses several issues concerning the substantiation of health claims through the examination of the regulations and guidelines in several countries. They include (1) importance of human- and product-based studies; (2) concept of scientific consensus; (3) authorization of claim wording; (4) availability of scientific evidence to public (confidentiality). The paper finally proposes a system based on generic and innovative health claims.

The effect of ingesting olestra-based foods on feeding behavior and energy balance in humans.

Abstract: This article reviews currently published works on the effects of olestra on appetite and energy intake (EI) in humans. To date 24 studies have examined the impact of olestra-containing foods on aspects of feeding behavior, which are published in 20 reports. The general response of human subjects to olestra-based decreases in dietary energy density (ED) is either poor caloric compensation or partial (nonmacronutrient specific) increases in EI. Averaging the degree of energy compensation across 22 studies gives a value of 27% (nonweighted mean). In studies where compensation occurred, fat intake but not EI was reduced. These effects appear to occur in both lean and obese, men and women and under a variety of conditions ranging from the laboratory to real life. However, all but two of these studies were short term. One study suggests that in subjects to whom weight loss is desirable these deficits can persist for up to 3 months. Subjects with no wish to lose weight may compensate better over longer periods. In another 3-month study, ingestion of olestra-based foods did not induce energy deficits but limited the significant weight gain seen on a full-fat control. The longer term effects of olestra on body weight requires further investigation. There is evidence that restrained eaters tend to eat slightly more of olestra-based foods if they know that they are reduced in fat and energy. This is probably a general response to low-fat foods rather than to olestra per se. The fact that olestra-based foods have the potential to provide the sensory qualities of real fat suggests that these foods may be particularly effective in habitual high-fat consumers with a sensory preference for dietary fat.

Comment: regulatory environment for dietary supplements and botanicals targeted to weight loss.

Abstract: (2001). Comment: Regulatory Environment for Dietary Supplements and Botanicals Targeted to Weight Loss. Critical Reviews in Food Science and Nutrition: Vol. 41, No. 1, pp. 43-44.

Ripe for study: complementary and alternative treatments for obesity.

Abstract: It has been said that in order to discover things, one must be ignorant.—Claude Bernard, French neurologist

The Battle Against Deceptive Weight Loss Ads

Abstract: “Lose up to 2 Pounds Daily Without Diet or Exercise”. “You lose weight even if you eat too much”. “New Medical Breakthrough! Lose A Pound A Day Without Changing What You Eat”.

Commentary on Alternative Treatments for Weight Loss

Abstract: (2001). Commentary on Alternative Treatments for Weight Loss. Critical Reviews in Food Science and Nutrition: Vol. 41, No. 1, pp. 39-40.