F. M. Clydesdale

Color as a factor in food choice

From birth, nature teaches us to make judgements on our environment based in large measure on color. As such, it plays a key role in food choice by influencing taste thresholds, sweetness perception, food preference, pleasantness, and acceptability. Its role is elusive and difficult to quantify, however, which at times has placed color in a secondary role to the other sensory characteristics, a position not entirely consistent with the facts. Color, in a quantitative sense, has been shown to be able to replace sugar and still maintain sweetness perception in flavored foods. It interferes with judgments of flavor intensity and identification and in so doing has been shown to dramatically influence the pleasantness and acceptability of foods. Studies in the literature have used cross-sectional population panels to study these effects, but a recent investigation of color-sensory interactions in beverages has compared the response of a college age group with the response of a panel consisting of a more mature population. Interestingly, the older group showed significant differences from the college age group in their response to the effects of color on several sensory parameters as well as showing a direct correlation between beverage consumption and color. Color is often taken for granted, but this position must be reevaluated in view of such studies and the need to create more appealing foods for different segments of our society.

Potential of Wheat-Based Breakfast Cereals as a Source of Dietary Antioxidants

Whole wheat- and wheat bran-based ready-to-eat breakfast cereals could be important sources of dietary antioxidants. Of the antioxidants in wheat, free and esterified phenolic acids seem to have the greatest potential to be beneficial to health. Phenolic acids from breakfast cereals possess strong antioxidant activity in vitro at concentrations that would be obtained from a normal serving of whole wheat cereal. In addition, acid conditions and enzymic hydrolysis increase the solubility and activity of wheat phenolics suggesting that the digestive process could be important in altering the antioxidant potential of wheat-based foods. Current research on the antioxidant activity of wheat phenolics suggests that further research is warranted to determine the potential benefits of these dietary antioxidants. In addition, identification of both biological (e.g. digestion) and food processing conditions that impact the distribution, stability and activity of wheat antioxidants is needed in order to be able to produce food products with maximum health benefits.

Colorimetry — methodology and applications∗

Color and appearance, those nebulous aspects of food acceptability which are taken for granted by most consumers, are coming under increasingly severe scrutiny. For this reason, it is essential that an adequate knowledge base for measurement be available to those working in the field. This base must be grounded upon the fact that color is a sensory phenomenon, and its measurement must include the physical, psychological, and physiological aspects. That is, measurement must involve tristimulus colorimetry, whether obtained by spectrophotometric or colorimetric techniques. It is the object of this article to review the general area of tristimulus colorimetry along with the techniques required for measurement. It is essential to include a section on the manipulation of data as well, since colorimetric data is often misused. Further treatment will be given to object-light interactions and how these affect not only measurement but sample perception, since manipulation of the physical parameters of the sample can affect the total appearance and color. Instruments and their usage will be reviewed so that decisions may be made on the correct instrument for a particular measuring system. In addition, a section will be devoted to on-line color measurement which may facilitate continuous processes. A final section of this article will deal with some advances in data manipulation and the development of new scales for color measurement. Fundamental colorimetric theory is essential in this area for proper usage. It is the aim of this paper to integrate theory with application in order to facilitate optimization of both the color of food and its measurement.

Antioxidant effect of aqueous extracts from wheat based ready-to-eat breakfast cereals

Aqueous extracts from high bran, whole grain and refined wheat cereals are capable of inhibiting iron/ascorbic acid induced phosphatidylcholine liposome oxidation. High bran and whole grain cereal extracts contained the highest antioxidant activity and were able to inhibit both iron and peroxyl radical-promoted oxidation. Antioxidants in aqueous extracts from the high bran cereal were found in both high and low molecular weight fractions. Aqueous extracts from cereal homogenates that were subjected to simulated gastrointestinal pH treatments exhibited greater antioxidant activity than the untreated aqueous extracts. These data indicate that wheat-based cereals contain antioxidants whose activity is enhanced by gastrointestinal conditions suggesting that they could be important dietary antioxidants.

A Review of Childhood and Adolescent Obesity Interventions

Obesity is one of the largest health problems facing Americans. Figures produced by the National Center for Health Statistics show that in 1999–2002, 15.8% of 6–11-year-olds were overweight as were 16.1% of adolescents aged 12–19. Some have proposed that interventions in childhood may be the best place to focus efforts to reduce the growing obesity epidemic. This paper examines several of the popular intervention strategies that have been proposed for youth and assesses the potential of these interventions for meaningful public health impacts. Findings show that most childhood obesity interventions completed to date produced only meager results, creating need for more well-designed studies that are tailored to the needs of specific age, ethnic and economic groups.

Funding food science and nutrition research: financial conflicts and scientific integrity

There has been significant public debate about the susceptibility of research to biases of various kinds. The dialogue has extended to the peer-reviewed literature, scientific conferences, the mass media, government advisory bodies, and beyond. Whereas biases can come from myriad sources, the overwhelming focus of the discussion to date has been on industry-funded science. Given the critical role that industry has played and will continue to play in the research process, the International Life Sciences Institute (ILSI) North America Working Group on Guiding Principles has, in this article, proposed conflict-of-interest guidelines regarding industry funding to protect the integrity and credibility of the scientific record, particularly with respect to health, nutrition, and food-safety science. Eight principles are enumerated, which specify the ground rules for industry-sponsored research. This article, which issues a challenge to the broader scientific community to address all bias issues, is only a first step; the document is intended to be dynamic, prompting ongoing discussion and refinement. In the conduct of public/private research relationships, all relevant parties shall 1) conduct or sponsor research that is factual, transparent, and designed objectively, and, according to accepted principles of scientific inquiry, the research design will generate an appropriately phrased hypothesis and the research will answer the appropriate questions, rather than favor a particular outcome; 2) require control of both study design and research itself to remain with scientific investigators; 3) not offer or accept remuneration geared to the outcome of a research project; 4) ensure, before the commencement of studies, that there is a written agreement that the investigative team has the freedom and obligation to attempt to publish the findings within some specified time frame; 5) require, in publications and conference presentations, full signed disclosure of all financial interests; 6) not participate in undisclosed paid authorship arrangements in industry-sponsored publications or presentations; 7) guarantee accessibility to all data and control of statistical analysis by investigators and appropriate auditors/reviewers; 8) require that academic researchers, when they work in contract research organizations (CRO) or act as contract researchers, make clear statements of their affiliation; and require that such researchers publish only under the auspices of the CRO.

Psychophysical Relationships Between Perceived Sweetness and Color in Cherry-Flavored Beverages

Sweetness of cherry-flavored and colored beverages, containing 3.2 to 4.8% sucrose, was quantified by a panel of 10 men and women, ages 22-50, using magnitude estimation. Five intensities of cherry colors were formulated using increasing volumes of Red 40 and a constant volume of both Blue 1 and imitation cherry flavoring. Color measurements from the Gardner XL-23 Colorimeter and the G. E. Recording Spectrophotometer were converted to L*, a* and b*. Sweetness was evaluated against sucrose concentration and arctan (a*/b*). Magnitude tests to evaluate color acceptability and pleasantness were also conducted. All magnitude estimates were normalized and subjected to a two-way ANOVA. Sweetness perception was highly correlated with increasing sucrose concentration (r2> .90), producing a power function exponent of 1.98. Sweetness increased approximately 3 to 13% with increasing color intensity in solutions containing 3.96 to 4.4% sucrose. The exponent describing the sweetness-color relationship was less than 1.0, and followed the power law over a narrow range of color intensities. Color 4 was the most acceptable color and color 3 containing 4.6% sucrose had the most pleasant taste. Color might be used to replace some sucrose and can optimize pleasurable taste sensations.

Psychophysical relationship between sweetness and redness in strawberry-flavored drinks

A consumer-like taste panel of 10 men and women, ages 22-50, evaluated the sweetness, pleasantness and color acceptability of five sweetened, strawberry-red colored beverages, containing 3.2% to 4.8% sucrose, using magnitude estimation. Five intensities of strawberry colors were formulated using increasing volumes of FD&C Red 40 and a constant volume of both FD&C Yellow 6 and imitation strawberry flavoring. Color measurements from the Gardner XL-23 colorimeter and the G. E. Recording Spectrophotometer were converted to L*, a*, b*. Sensory responses were evaluated against the value arctan (a*/b*), representing color intensity, and sucrose concentration, as percent sugar. Sweetness perception increased with increasing sucrose concentration, producing a slope greater than 2.00 (r2≥0.87) but produced an exponent less than 1.0 (r2<0.91) when evaluated against arctan (a*/b*). Sweetness increased approximately 2 to 12% with increasing color intensity in 4% sucrose solutions. Perceived sweetness was influenced by pleasantness effects and color acceptability. Color 3 samples were rated as the sweetest, most pleasant-tasting drinks and had the most acceptable color. The color-sweetness function was linear over a narrow color range.

The effects of postharvest treatment and chemical interactions on the bioavailability of ascorbic acid, thiamin, vitamin a, carotenoids, and minerals

All recent health recommendations include admonitions to reduce calories, maintain desirable weight, reduce fat, increase complex carbohydrates, and ensure an adequate intake of nutrients. Such recommendations require that we know not only nutrient composition of foods, but also potential losses and decreased bioavailability due to postharvest treatment and chemical interactions. This article discusses in some detail the reactions of concern that cause such changes and their potential alleviation with several key nutrients. The nutrients discussed were chosen as a result of the conclusions of the Joint Nutrition Monitoring Report of the Department of Health and Human Services and the U.S. Department of Agriculture. Obviously other choices could have been made, but the authors felt that the nutrients chosen--ascorbic acid, thiamin, vitamin A, carotenoids, calcium, and iron--were representative of a key profile of nutrients whose reactivity makes them vulnerable to losses in bioavailability, as well as being noted in the Joint Nutrition Monitoring Report.

The psychophysical relationships between color and flavor

Psychophysics has become a well-defined discipline in science and is undergoing a period of transition from the theoretical and academic to the applied. Certainly the use of magnitude estimation in flavor evaluation is becoming more accepted, and concurrently the food research area is utilizing the colorimetric techniques which are available. However, there has been virtually no investigation carried out on the quantitative relationships which exist between color and flavor in a psychophysical sense. Intuitively, many researchers state the qualitative effect of color on flavor, but the quantification of these techniques is practically nonexistent. This paper will attempt to summarize the psychophysical techniques which are available for such studies, as well as discuss the importance of these studies. Great controversy exists concerning the need for colorants in food. If color does indeed affect flavor quantitatively, it will affect intake and, therefore, final nutritional status of the public in a quantitative manner. This controversy should be resolved in the light of fact, not intuition.