A comparison of the floristics and leaf chemistry of the tree flora in two Malaysian rain forests and the influence of leaf chemistry on populations of colobine monkeys in the Old World

A comparative floristic survey of lowland tropical rain forest at Kuala Lompat, Krau Game Reserve, West Malaysia and at Sepilok Virgin Jungle Reserve, Sabah, East Malaysia, revealed significant differences in the composition of canopy species, notably in the relative paucity of Dipterocarpaceae and abundance of Leguminosae at Kuala Lompat. A further comparison with data from other sites in Malesia indicated that Kuala Lompat was rather atypical, representing an extreme example of the relatively legume rich and dipterocarp poor forests of West Malaysia. Conversely, the predominance of dipterocarps and lack of legumes at Sepilok was similar to other sites in Borneo. Young and mature leaves were collected from a representative sample of the canopy flora of the two study sites; the levels of nitrogen, fibre, total phenolics and condensed tannins, and degree of digestibility by cellulase and pepsin, were measured. Levels of fibre, nitrogen and phenolics differed significantly between the two floras; foliage from Kuala Lompat being, on the whole, richer in nitrogen but lower in phenolics and fibre. As a consequence of the lower levels of fibre, and less certainly of phenolics, the Kuala Lompat foliage was comparatively more digestible. Possible reasons for the differences in foliar biochemistry between the two sites are discussed. Differences in rainfall and in soil quality are regarded as potential evolutionary causes. A further comparison of the chemical profiles with data for other forests in India and Africa indicate that Sepilok is a site in which trees invest heavily in quantitative defences such as fibre and phenolics whereas trees at Kuala Lompat place a lower emphasis on the production of these. Finally, attention is drawn to the use of foliar chemical profiles in predicting the carrying capacity for colobine monkeys at each of the five Old World forests where data are available. It was found that the ratio of nitrogen to fibre correlated well with the biomass of colobines at the five sites.     

INSTRUMENTAL AND SENSORY EVALUATION OF TEXTURAL ATTRIBUTES IN CHEESE ANALOGS: A CORRELATION STUDY

The objective of this study was to investigate the usefulness of an array of statistical techniques to describe relationships between instrumental data and non‐oral sensory texture profiling scores by using a range of model processed cheese analogs as example. Pairwise correlation, used as an exploratory tool, showed no significant correlation for flexibility and greasiness with any individual instrumental parameter. Stepwise regression, principal component regression and partial least squares regression were used to generate models for firmness, stickiness and curdiness of the analogs studied. No models could be generated for flexibility and greasiness, and models for rubberiness had poor quality of fit compared with the other sensory attributes. In general, firmness, stickiness and curdiness were satisfactorily modeled by using chemical data and small deformation rheological parameters. Compression data (large deformation), often used in correlation studies regarding the texture of cheese, did not necessarily lead to better correlation results in comparison with other instrumental parameters used in this research.