Bitter taste, phytonutrients, and the consumer: a review

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.

Natural Pigments: Carotenoids, Anthocyanins, and Betalains — Characteristics, Biosynthesis, Processing, and Stability

Phytoalexins: enzymology and molecular biology.

Post harvest biology and technology of citrus fruits is gaining importance as the therapeutic value of citrus fruits is realized and supported by the increase in health awareness among the general public This book is the most comprehensive reference on citrus fruit biology, biotechnology and quality Basic and applied scientific information is interwoven to serve the researcher, marketer, scientist, nutritionist, or dietician With discussions of fruit morphology, anatomy, physiology and biochemistry and chapters on growth phases, maturity standards, grades and physical and mechanical characteristics of citrus trees, this book provides the foundation for understanding growth, harvest and post harvest aspects of these important plants Insect-pests and diseases, irrigation, nutrition and rootstocks are also addressed * Provides practical tips for post harvest management * Includes all aspects of citrus fruit biology, technology and quality evaluation * Discusses biotechnological applications and potential fresh citrus fruit quality improvement * Evaluates medicinal and therapeutic applications and recent clinical findings * Exhaustive glossary included

Citrus Fruit: Biology, Technology and Evaluation

Publisher Summary The chapter presents a discussion on plant growth-regulating (PGR) substances in the rhizosphere, with emphasis on microbial production and functions. The chapter discusses the rhizosphere as a site of plant-microbe interactions; plant growth-regulating substances and their sources; biochemistry of microbial production of PGRs; production of PGRs by rhizosphere microorganisms; metabolism of PGRs in soil; and ecological significance of PGRs produced in the rhizosphere. The chapter provides a better understanding of the mechanisms of actions of microbially derived PGRs and their interactions with plants. Moreover, development of hormone-deficient plant mutants can provide opportunities to clearly define the role of microbially produced PGRs in plan-microbe interactions. An understanding of these aspects can aid in the utilization of microbial PGRs for the betterment and benefit of sustainable agriculture.

Plant growth-regulating substances in the rhizosphere: microbial production and functions

Specific thin-layer chromatography assay of limonin, a citrus bitter principle

Ethylene-accelerated limonoid metabolism in citrus fruits. Process for reducing juice bitterness

The thresholds of limonin and naringin in water and limonin in orange juice were determined in the presence of varying amounts of neodiosmin (NEO), the flavone analog of the bitter flavanone neohesperidin. Up to 40 ppm of NEO in water solution was essentially tasteless, but as little as 10 ppm in water increased the threshold of naringin and limonin 3.5- and 4.0-fold, respectively. Regression analysis showed the relation between limonin and naringin threshold and NEO concentration in water was best described by a power function with similar slope exponents for naringin and limonin. This indicated that increasing concentrations of NEO had a similar bitter suppressive effect for both compounds. The data for limonin threshold and NEO concentration in orange juice was also described best by a power function but with a much smaller slope exponent. Nevertheless, NEO was effective in significantly reducing bitterness in orange juice at threshold and suprathreshold levels of limonin. The addition of 60-100 ppm of NEO to orange juice containing 10 ppm of added limonin reduced limonin bitterness to the equivalent of 4–5 ppm of limonin in orange juice.

V.P. Maier

Papers

Specific thin-layer chromatography assay of limonin, a citrus bitter principle

Ethylene-accelerated limonoid metabolism in citrus fruits. Process for reducing juice bitterness

Effect of neodiosmin on threshold and bitterness of limonin in water and orange juice

Biosynthesis of limonoids in Citrus seedlings

Cytokinins Inhibit Abscisic Acid Biosynthesis in Cercospora Rosicola