Journal of the Science of Food and Agriculture 

About: Journal of the Science of Food and Agriculture is an academic journal published by Wiley. The journal publishes majorly in the area(s): Medicine & Chemistry. It has an ISSN identifier of 0022-5142. Over the lifetime, 19226 publications have been published receiving 588622 citations.

The phenolic constituents of Prunus domestica. I.—The quantitative analysis of phenolic constituents

Abstract: Methods for the quantitative analysis of anthocyanins, leuco-anthocyanins, flavanols and total phenols in plant tissue extracts are critically examined and suitable modifications of existing methods are described.

A procedure to measure the antiradical efficiency of polyphenols

Abstract: The kinetic behaviour of polyphenols common in fruits as free radical scavengers was studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH.). After addition of different standard concentrations to DPPH. (0.025 g litre-1), the percentage of remaining DPPH. was determined at different times from the absorbances at 515 nm. The percentage remaining DPPH. against reaction time followed a multiplicative model equation: In [DPPH.REM] = b 1n t + 1n a. The slopes of these equations may be useful parameters to define the antioxidant capacity. The steeper the slope, the lower the amount of antioxidant necessary to decrease by 50% the initial DPPH. concentration (EC50). This parameter, EC50, is widely used to measure antioxidant power, but it does not takes into account the reaction time. Time needed to reach the steady state to the concentration corresponding at EC50 (T(EC50)) was calculated, and antiradical efficiency (AE) was proposed as a new parameter to characterise the antioxidant compounds where AE = 1/EC50 T(EC50). It was shown that AE is more discriminatory than EC50. AE values are more useful because they also take into account the reaction time. The results have shown that the order of the AE (x 10(-3)) in the compounds tested was: ascorbic acid (11.44) > caffeic acid (2.75) greater than or equal to gallic acid (2.62) > tannic acid (0.57) greater than or equal to DL-alpha-tocopherol (0.52) > rutin (0.21) greater than or equal to quercetin (0.19) > ferulic acid (0.12) greater than or equal to 3-tert-butyl-4-hydroxyanisole, BHA (0.10) > resveratrol (0.05).

Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies

Abstract: A new liquid marker, cobalt-ethylenediamine tetraacetic acid (EDTA), and two solid markers, chromium (Cr) and cerium (Ce) mordanted plant cell walls, were investigated. Synthesis and methods of analysis are described for the markers. The Cr- and Ce-cell wall complexes were tested for stability to EDTA, hydrochloric acid and rumen microorganisms. Plant cell walls were rendered indigestible by mordanting with Cr and 98% of the marker remained on the fibre after a simulated sequence (in vitro) of digestion. Ce-mordanted cell walls were 35% digestible in vitro using a rumen culture, and 56% of the marker could be washed off the remaining fibre. Treatment with EDTA removed all Ce and 15% of the Cr. Hydrochloric acid (0.01M) had a negligible effect on the removal of Cr from the cell walls, whereas 0.1M acid removed, on average, 10% of the marker. Losses of Cr from the mordant may be related to the quality of the preparation. Co-EDTA was found to be comparable to Cr-EDTA. The urinary excretion of Cr and Co was 2–3% in most animals except in rabbits, which excreted as much as 30% of the liquid markers in the urine.

Plant L‐ascorbic acid: chemistry, function, metabolism, bioavailability and effects of processing

Abstract: Humans are unable to synthesise L-ascorbic acid (L-AA, ascorbate, vitamin C), and are thus entirely dependent upon dietary sources to meet needs. In both plant and animal metabolism, the biological functions of L-ascorbic acid are centred around the antioxidant properties of this molecule. Considerable evidence has been accruing in the last two decades of the importance of L-AA in protecting not only the plant from oxidative stress, but also mammals from various chronic diseases that have their origins in oxidative stress. Evidence suggests that the plasma levels of L-AA in large sections of the population are sub-optimal for the health protective effects of this vitamin. Until quite recently, little focus has been given to improving the L-AA content of plant foods, either in terms of the amounts present in commercial crop varieties, or in minimising losses prior to ingestion. Further, while L-AA biosynthesis in animals was elucidated in the 1960s, 1 it is only very recently that a distinct biosynthetic route for plants has been proposed. 2 The characterisation of this new pathway will undoubtedly provide the necessary focus and impetus to enable fundamental questions on plant L-AA metabolism to be resolved. This review focuses on the role of L-AA in metabolism and the latest studies regarding its bio- synthesis, tissue compartmentalisation, turnover and catabolism. These inter-relationships are considered in relation to the potential to improve the L-AA content of crops. Methodology for the reliable analysis of L-AA in plant foods is briefly reviewed. The concentrations found in common food sources and the effects of processing, or storage prior to consumption are discussed. Finally the factors that determine the bioavailability of L-AA and how it may be improved are considered, as well as the most important future research needs. # 2000 Society of Chemical Industry

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

Abstract: 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.