Fruit development, flavonoids

Bogs J, Ebadi A, McDavid D, Robinson SP. 2006. Identification of the flavonoid hydroxylases from grapevine and their regulation during fruit development. Plant Physiol 140 279-291. 

HCA may also be covalenty attached to aliphatic components of cutin and suberin. The amount of covalently bound phenolic compounds m-, /7-coumaric acids and flavonoids) in tomato fruit cutin increased during fruit development and accounted for as much as 6% of cutin membranes. Protoplasts isolated from immature tomato fruit secrete a wall that has been shown to contain suberin, in which phenolic compounds formed 25% of total monomers [3]. 

Different fruits and vegetables vary significantly in their structural constituents, macronutrients (proteins, oils, and carbohydrates), and micronutrients such as flavonoid profiles. It is almost impossible to develop one optimal method for extraction, separation, and analysis for each and every different fruit or vegetable. However, because of the relatively similar chemistry and biochemistry of flavonoids, some general statements can be abstracted from the existing literature. Flavonoids of fruits and vegetables... 

Moriguchi T, Kita M, Tomono Y, Endo-Inagaki T, Omura M (2008) Gene expression in flavonoid biosynthesis correlation with flavonoid accumulation in developing citrus fruit. Physiol Plant 111 66-74... 

A comprehensive and critical review of food flavonoid literature has led to the development of a food composition database for flavonols, flavones, procyanidins, catechins, and flava-nones. This database can now be used and continuously updated to estimate flavonoid intake of populations, to identify dietary sources of flavonoids, and to assess associations between flavonoid intake and disease. However, there is a need for better food composition data for flavones, procyanidins, and flavanones as current literature is sparse particularly for citrus fruits, fruit juices, and herbs. In addition, anthocyanin food composition data are lacking although validated methods of determination are becoming available. 

Hertog et al. (119) developed a fast HPLC method for the identification and quantification of five major flavonoid aglycones (quercetin, kaempferol, myricetin, luteolin, and apigenin) in freeze-dried vegetable and fruits. However, due to the inadequate resolution of quercetin and luteolin on RP-HPLC on Nova-Pak C]8, two different eluents of different solvent strength and viscosity were utilized. The conditions for hydrolysis and extraction were tested based on different conditions of hydrochloric acid concentration (1.2-2.0 M), reaction period (0.5-6 h), and meth-... 

The major groups of phytopolyphenols are the flavonoids and flavanoids, which are important in contributing the flavor and color of many fruits and vegetables. They play important roles in the normal growth, development, and defense of plants. Recently, both flavonoids and flavanoids have been intensively investigated... 

A general method for the evaluation of phenolic compounds in fermented beverages, fruit juices and plant extracts was developed using gradient HPLC and coulometric detection. In a 10 p,L injection it was possible to identify and determine 36 different flavonoids and simple and complex phenols, without sample extraction, purification or concentration, in several kinds of beers, red and white wines, lemon juice and soya, forsythia and tobacco extracts. This may also be useful for the characterization of beverages and extracts . 

Oxidation of Phenolic Compounds. Phenolic compounds are widespread throughout the plant kingdom and are prevalent in fruits where they are important contributors to color and flavor (46). Phenolic compounds, particularly flavonoids and derivatives of chlorogenic acid, play a crucial role in the development of a number of postharvest disorders through their oxidation to brown compounds that discolor many fruits and vegetables and substantially reduce their quality. A number of enzymes catalyze the biosynthesis or oxidation of phenolic compounds, among them phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), cinnamic acid-4-hydroxylase (CA4H), polyphenol oxidase (PPO), and catechol oxidase (CAO). The chemistry... 

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