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14 - Dietary analysis II: food chemistry
- Edited by Joanna M. Setchell, University of Durham, Deborah J. Curtis, Oxford Brookes University
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- Book:
- Field and Laboratory Methods in Primatology
- Published online:
- 05 June 2012
- Print publication:
- 03 February 2011, pp 255-270
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- Chapter
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Summary
INTRODUCTION
The preceding chapter introduced dietary analysis and discussed physical aspects of potential foods as they might influence feeding behaviour. Here, we deal with chemical aspects of potential foods. From the outset though, we should point out that attempts to explain the influence of chemical factors on primate nutrition, and the dietary factors that promote or deter the uptake of nutrients, are limited by our understanding of how the primate gut operates. It is unclear what the optimal dietary requirements are even for humans. Gut research is developing on both theoretical (see, for example, Jumars, 2000) and practical levels (Dominy et al., 2004), but it is important to point out that the effective rate of uptake is not simply a question of enzymatic action. The quantity of plant fibre that a primate ingests has a major influence on the rate of passage of food through the gut and thus digestibility (Lambert, 2002). Variable gut populations of microorganisms and parasites also play a large positive or negative role, particularly in relation to specializations in the stomach or large intestine. The situation is even less clear when it comes to chemical compounds that act as feeding deterrents, toxins or anti-nutritional factors. These have largely been bred or processed out of the agricultural products on which humans feed, so they have received relatively little attention in food science.
13 - Dietary analysis I: food physics
- Edited by Joanna M. Setchell, University of Durham, Deborah J. Curtis, Oxford Brookes University
-
- Book:
- Field and Laboratory Methods in Primatology
- Published online:
- 05 June 2012
- Print publication:
- 03 February 2011, pp 237-254
-
- Chapter
- Export citation
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Summary
INTRODUCTION
This chapter and the next focus on measurements of the physical and chemical attributes of potential foods that primates select or reject. The major reason for analysing primate diets in this manner is to understand the basis for their food choice. Observing primates as they feed quickly raises questions in the observer's mind about the possible foraging strategies that the animals might be following in order to survive. How do primates distinguish food from what is otherwise scenery? Can we measure the attributes of potential foods in the form in which primates are actually sensing them? What do primates get out of the foods they choose and are their choices, based on sensory capabilities, optimal in terms of nutrients? Tests of hypotheses that address these questions will require objective dietary analysis (e.g. for colour: Osorio et al., 2004). It is important to tailor your measurements to the questions being asked.
The physicochemical characteristics of foods may form The physicochemical characteristics of foods may form important sensory cues for their detection, selection and subsequent processing by primates, but all these characteristics are affected to some extent by specimen storage. Physical characteristics, such as colour, geometry and mechanical properties, may change drastically and rapidly, so it is often important and sometimes vital to make measurements almost immediately, while the specimen is fresh.
12 - Dietary analysis I: Food physics
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- By Peter W. Lucas, University of Hong Kong, Daniel Osorio, University of Sussex, Nayuta Yamashita, University of Southern California, Jonathan F. Prinz, Wageningen Centre for Food Sciences, Nathaniel J. Dominy, University of Chicago, Brian W. Darvell, University of Hong Kong
- Edited by Joanna M. Setchell, University of Surrey, Roehampton, Deborah J. Curtis, University of Surrey, Roehampton
-
- Book:
- Field and Laboratory Methods in Primatology
- Published online:
- 05 June 2012
- Print publication:
- 18 September 2003, pp 184-198
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- Chapter
- Export citation
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Summary
INTRODUCTION
Both this chapter and the next focus on measurements of the physical and chemical attributes of potential foods that primates select or reject. The major reason for analysing the diets of primate in this manner is to understand the basis for their food choice. Observing primates as they feed quickly raises questions in the observer's mind about the possible foraging strategies that the animals might be following in order to survive. How do primates distinguish food from what is otherwise scenery? Can we measure the attributes of potential foods in the form that primates are actually sensing them? What do primates get out of the foods they choose and are their choices, based on sensory capabilities, optimal in terms of nutrients? Tests of hypotheses that address these questions will require objective dietary analysis. It is important to tailor your measurements to the questions being asked.
The physiochemical characteristics of foods may form important sensory cues for their detection, selection and subsequent processing by primates, but all these characteristics are affected to some degree by specimen storage. Physical characteristics, such as colour, geometry and mechanical properties, are ruined. So it is often important and sometimes vital to make measurements almost immediately, while the specimen is fresh. The alternative of drying specimens for later chemical analysis not only involves a substantial time lag between fieldwork and subsequent access to a laboratory but also can lead to inaccurate results.
13 - Dietary analysis II: Food chemistry
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- By Peter W. Lucas, University of Hong Kong, Richard T. Corlett, University of Hong Kong, Nathaniel J. Dominy, University of Chicago, Hafejee C. Essackjee, University of Liverpool, Pablo Riba-Hernandez, University of Costa Rica, Kathryn E. Stoner, Universidad Nacional Autonomade México, Nayuta Yamashita, University of Southern California
- Edited by Joanna M. Setchell, University of Surrey, Roehampton, Deborah J. Curtis, University of Surrey, Roehampton
-
- Book:
- Field and Laboratory Methods in Primatology
- Published online:
- 05 June 2012
- Print publication:
- 18 September 2003, pp 199-213
-
- Chapter
- Export citation
-
Summary
INTRODUCTION
Chapter 12 introduced dietary analysis and discussed physical aspects of potential foods as they might influence feeding behaviour. Here, we deal with chemical aspects of potential foods. Attempts to explain the influence of chemical factors on primate nutrition, and the dietary factors that promote or deter the uptake of nutrients, are limited by our understanding of how the primate gut operates. We are still not sure what the optimal dietary requirements are for humans (Challem, 1999). Research is developing both on theoretical (e.g. Jumars, 2000a, b) and practical levels (Minekus et al., 1999), but the effective rate of uptake is not simply a question of enzymatic action. The quantity of plant fibre that a primate ingests is a major influence on the rate of passage of food through the gut and thus digestibility. A variable gut population of micro-organisms and parasites also play a large positive or negative role, as do specialisations in the stomach or large intestine. The situation is even less clear when it comes to chemical compounds that act as feeding deterrents, toxins or anti-nutritional factors. These have largely been bred or processed out of the agricultural products on which humans feed, so they have received relatively little attention in food science. Currently, these chemicals are assessed by crude measures, such as total phenolics, which, of necessity, ignore the wide range of variation within each class of chemicals in the nature and intensity of the biological effect.