THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

http://www.dietcan.net/docs/Polifenoles%20en%20alimentos%20y%20biodisponibilidad.pdf

Polyphenols: food sources and bioavailability

Antioxidant properties of phenolic compounds

Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.

Polyphenols: Chemistry, Dietary Sources, Metabolism, and Nutritional Significance

Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies

Dietary phenolics: chemistry, bioavailability and effects on health.

This review defines the range of forms in which cinnamates (p-coumarates, caffeates, ferulates and sinapates) occur in foods and beverages subdividing them into (i) the classic chlorogenic acids and close allies, (ii) other esters, amides and glycosides, and (iii) transformation products formed during processing. Cinnamate derivatives which would not release cinnamic acid by hydrolysis are excluded. The quantitative data are reviewed concisely and attention is drawn to certain shortcomings, in particular a complete absence of data for certain commodities (breakfast cereals, baked goods, tomato products and nuts) and minimal data for pulses, legumes and processed or cooked foods. In addition, more data are required for the edible portion of modern varieties. By extrapolating from such data as are available the important source(s) (i) of individual cinnamates (regardless of the conjugate type) and (ii) of each major class of conjugate, have been identified as follows: (i) Cinnamates: caffeic acid: coffee beverage, blueberries, apples, ciders; p-coumaric acid: spinach, sugar beet fibre, cereal brans; ferulic acid: coffee beverage, citrus juices, sugar beet fibre, cereal brans; sinapic acid: broccoli, kale, other leafy brassicas, citrus juices. (ii) Conjugates: caffeoylquinic acids: coffee beverage, blueberries, apples, ciders; p-coumaroylquinic acids: sweet cherries; feruloylquinic acids: coffee beverage; tartaric conjugates: spinach, lettuce, grapes and wines; malic conjugates: lettuce, spinach, possibly legumes; rosmarinic acid: culinary herbs, mixed herbs, possibly stuffings; cell wall conjugates: spinach, sugar beet fibre, cereal brans. It seems likely that the UK population will fall into several categories depending on (i) their consumption of coffee, (ii) their consumption of bran, and (iii) their consumption of citrus. Those who drink several cups of coffee per day augmented by bran and citrus might easily ingest 500-800mg cinnamates (or even 1 g for the greatest coffee ingest consumption) whereas those who eschew all these and take little fresh fruit or vegetables might struggle to consume 25 mg.

Chlorogenic acids and other cinnamates – nature, occurrence and dietary burden

The fragmentation behavior of 18 chlorogenic acids that are not substituted at position 1 has been investigated using LC-MS(4) applied to a methanolic coffee bean extract and commercial cider (hard cider). Using LC-MS(3), it is possible to discriminate between each of the three isomers of p-coumaroylquinic acid, caffeoylquinic acid, feruloylquinic acid, and dicaffeoylquinic acid, and a hierarchical key has been prepared to facilitate this process when standards are not available. MS(4) fragmentations further support these assignments, but were not essential in reaching them. The distinctive behavior of 4-acyl and 3-acyl chlorogenic acids compared with the 5-acyl chlorogenic acids is a key factor permitting these assignments. The fragmentation patterns are dependent upon the particular stereochemical relationships between the individual substituents on the quinic acid moiety. Fragmentation is facilitated by 1,2-acyl participation and proceeds through quinic acid conformers in which the relevant substituents transiently adopt a 1,3-syn-diaxial relationship. Selected ion monitoring at m/z 529 clearly indicated the presence in coffee of six caffeoylferuloylquinic acid isomers, whereas previously only two or three had been demonstrated. The hierarchical key permitted specific structures to be assigned to each of the six isomers. These assignments are internally consistent and consistent with the limited data previously available.

Hierarchical scheme for LC-MSn identification of chlorogenic acids

This paper summarises the occurrence in foods and beverages of the cinnamic acids, their associated conjugates and transformation products. Quantitative data are lacking for some commodities known to contain them, but it is clear that for many people coffee will be the major source. The daily dietary intake of total cinnamates may vary substantially from almost zero to perhaps close to 1 g. The data relating to their absorption and metabolism are presented along with a consideration of their possible in vivo effects. Data for true bioavailability are incomplete: in particular it is not clear whether availability differs markedly with the form of the conjugate, and whether as a consequence some dietary sources may be superior to others.

Chlorogenic acids and other cinnamates - nature, occurrence, dietary burden, absorption and metabolism

This paper reviews the literature on the occurrence of anthocyanins in foods and their transformation during processing, including the formation of adducts and derived tannins. Data describing the safety of anthocyanins and possible dietary effects are examined. Attention is drawn to some misquotations in the literature and to some serious gaps in our knowledge, in particular, the lack of pharmacokinetic data in humans essential to an understanding of associated biological effects.

Michael N. Clifford

Papers

Dietary phenolics: chemistry, bioavailability and effects on health.

Chlorogenic acids and other cinnamates – nature, occurrence and dietary burden

Hierarchical scheme for LC-MSn identification of chlorogenic acids

Chlorogenic acids and other cinnamates - nature, occurrence, dietary burden, absorption and metabolism

Anthocyanins – nature, occurrence and dietary burden