It is proposed to describe briefly the rise in popularity of the tomato during the 20th century to become the world's fourth most significant fruit, making an important contribution to human nutrition. The grading standards for fruit used in various major tomato-producing countries will be outlined. A major part of the review will be devoted to describing changes in composition during the maturation, ripening, preservation, and storage of good quality tomatoes especially as regards carbohydrates, organic and amino acids, proteins, steroids, pigments, minerals, and the lipids, volatiles, and other minor constituents. A range within which composition should normally fall will be given. Additionally, the effects on composition of environment, cultivar, nutrition, and physiological disorders inter alia will be described. How new growing methods and genetic manipulation could influence the tomato of the future will also be considered.

The constituents of tomato fruit — the influence of environment, nutrition, and genotype

One of the earliest attempts to gauge the involvement of ascorbic acid (AA) in the overall metabolism was thc determination of its distribution in thc tissues. A thorough knowledge of its occurrence was believed to be pertinent to the elucidation of the physiological role of the vitamin in the organism. The availability of labeled AA, metabolites, and analogues has made it possible to follow up the appearance of these compounds or mctabolites thereof in thc various tissues of animals by means of dissecting the animals with subsequent determination of the radioactive material accumulated by the tissues or by means of whole-body autoradiography, as described in detail by Kalberer.'

Distribution of ascorbic acid, metabolites and analogues in man and animals.

Publisher Summary This chapter discusses the deamidation of glutaminyl and asparaginyl residues in peptides and proteins. The occurrence of glutaminyl and asparaginyl residues in peptides and proteins is so widespread that these residues have become known as 2 of the 20 most commonly occurring amino acid residues. It has been hypothesized that these residues play static roles in protein structure and also play dynamic roles as molecular timers of biological events. Deamidation of glutaminyl and asparaginyl residues has been responsible for artifacts in peptide and protein chemistry. The rate of deamidation of these residues has been shown to be dependent upon primary sequence, secondary and tertiary structure, temperature, pH, ionic strength, and special intermolecular interactions. Deamidation has been found to occur in a wide variety of different proteins and may be expected to occur in most proteins under physiological conditions. Many of the essential processes in living things may be timed by deamidation of glutaminyl and asparaginyl residues. These molecular timers are under simple genetic control, are adjustable to many different timed intervals, and are easily implementable by means of the important changes that they can effect in the proteins in which they are included.

Deamidation of Glutaminyl and Asparaginyl Residues in Peptides and Proteins

The determination of diketo l-gulonic acid, dehydro-l-ascorbic acid, and l-ascorbic acid in the same tissue extract by the 2, 4-dinitrophenylhydrazine method.

Chemical determination of ascorbic, dehydroascorbic, and diketogulonic acids.

The chemical behaviour of dehydro-l-ascorbic acid in vitro and in vivo.

/pdf/the-isolation-of-barium-and-calcium-diketo-l-gulonates-and-5ae1i7apeq.pdf

The isolation of barium and calcium diketo-l-gulonates and the biological significance of 2:3-diketo-l-gulonic acid.

/pdf/the-fixation-and-retention-of-ascorbic-acid-by-the-guinea-1qd7hsf8up.pdf

The fixation and retention of ascorbic acid by the guinea-pig

The determination of 2:3-diketo-l-gulonic acid.

/pdf/interfering-substances-in-the-roe-and-kuether-method-for-the-54m7aup5f3.pdf

J. R. Penney

Papers

The chemical behaviour of dehydro-l-ascorbic acid in vitro and in vivo.

The isolation of barium and calcium diketo-l-gulonates and the biological significance of 2:3-diketo-l-gulonic acid.

The fixation and retention of ascorbic acid by the guinea-pig

The determination of 2:3-diketo-l-gulonic acid.

Interfering substances in the Roe and Kuether method for the determination of ascorbic acid