Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Phenolics in food and nutraceuticals

Phenolics in cereals, fruits and vegetables: Occurrence, extraction and analysis

Minimally processed fresh (MPF) fruits and vegetables are good media for growth of microorganisms. They have been involved in outbreaks because of the consumption of products contaminated by pathogens. They are also sensitive to various spoilage microorganisms such as pectinolytic bacteria, saprophytic Gram-negative bacteria, lactic acid bacteria, and yeasts. Contamination of MPF fruits and vegetables occurs at every stage of the food chain, from cultivation to processing. Polluted environments during cultivation or poor hygienic conditions in processing increase the risk of contamination with foodborne pathogens. Although MPF fruits and vegetables may harbor psychrotrophic microorganisms such as fluorescent pseudomonads or Listeria monocytogenes, good control of refrigeration temperature limits growth of spoilage and pathogenic microorganisms. Modified atmospheres are often efficient to maintain or improve visual organoleptic quality of MPF fruits and vegetables, but their effects on microorganisms are inconsistent. Chemical disinfection can partially reduce the initial bacterial contamination; irradiation seems to be more efficient. The applications of legislations and quality assurance systems to control contamination, survival, and growth of foodborne pathogens in MPF fruits and vegetables are discussed.

The microbiology of minimally processed fresh fruits and vegetables

Comparative study on the antibacterial activity of phytochemical flavanones against methicillin-resistant Staphylococcus aureus

Differently substituted flavanones were isolated from Leguminosae and their antibacterial activity was comparatively studied against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MICs) of phytochemical flavanones to clinical isolates of MRSA were determined by a serial agar dilution method. The structure-activity relationship has indicated that 2',4'- or 2',6'-dihydroxylation of the B ring and 5,7-dihydroxylation of the A ring in the flavanone structure are important for significant anti-MRSA activity and that substitution with a certain aliphatic group at the 6- or 8-position also enhances the activity. Among the thirteen flavanones tested, tetrahydroxyflavanones with these structural characteristics isolated from Sophora exigua and Echinosophora koreensis showed intensive activity to inhibit the growth of all MRSA strains at 3.13-6.25 micrograms/ml. The present hydroxyflavanones would be useful in the phytotherapeutic strategy against MRSA infections.

Comparative Study on the Antibacterial Activity of Phytochemical Flavanones against Methicillin-resistant Staphylococcus aureus.

Isolation and antimicrobial activity of the phytoalexin 6-methoxymellein from cultured carrot cells

Changes in the synthetic activities of nucleic acids and protein and in the amount of adenine nucleotides in Daucus carota cells have been examined during a period of rapid cell division and during the stationary phase. Cell growth and the syntheses of those macromolecules in the logarithmic phase were significantly enhanced by increasing the concentration of phosphate in the medium. In a phosphate-rich medium, RNA and protein rapidly degraded and the number of cells with denatured cytoplasm increased when the culture entered into a stationary phase because of exhaustion of glucose. On the other hand, when the growth ceased by exhaustions of phosphate and nitrogen, the cells slowly underwent physiological changes leading to cellular senescence. The value of adenylate energy charge during the growth period was about 0.8–0.9 irrespective of the growth rate. After cessation of growth the value declined to about 0.5.

Physiological Changes of Carrot Cells in Suspension Culture during Growth and Senescence

The carrot phytoalexin, 6-methoxymellein, accumulated in carrot suspension culture when it was incubated with a partial hydrolysate of carrot cells obtained by pectinase or trypsin treatment. 6-Methoxymellein also accumulated when these enzymes were added to the culture. In both cases, phytoalexin content decreased rapidly after maximum accumulation was attained, suggesting that the cultured carrot cells metabolized the phytoalexin. Cultured carrot cells incubated with the phytoalexin formed three different metabolites: among them, two which accumulated in the medium, were identified as the β-glucoside of 6-methoxymellein and 6-hydroxymellein. 6-Methoxymellein was found to be toxic to the host plant and induced a lag period in the growth of cultured carrot cells at low concentration. When it was added at concentrations higher than 0·5 m m , it caused a rapid decrease in viable cell number.

Production and metabolism of 6-methoxymellein in cultured carrot cells

A strain of carrot cells (Daucus carota cv. Kintoki) grew exponentially in the presence of 2,4-dichlorophenoxyacetic acid (2,4-D, 1 mg/1) with a doubling time of about 2 days. When those cells were transferred to a medium lacking 2,4-D, they continued to grow at almost the same rate for about a week. When the cells were again transferred to the auxin-free medium, the rate of cell division gradually decreased. After the cell division had ceased, cells were returned to the ordinary 2,4-D medium. A burst of cell divisions occurred after about 2 days. Timing of DNA synthesis and of mitosis suggested that the cells had been arrested at G1 phase. In a medium containing indoleacetic acid instead of 2,4-D, the auxin was rapidly degraded and the culture was similarly synchronized as in the auxin-omitted medium.

Partial Synchronization of Carrot Cell Culture by Auxin Deprivation

Four peptaibols, named trichokonins (TKs) V, VI, VII, and VIII, were isolated from the culture broth of Trichoderma koningii OUDEMANS. Primary structures of these peptaibols were elucidated by electrospray ionization mass spectrometry (ESI-MS), FAB-MS and collision-induced dissociation (CID) techniques along with nuclear Overhauser enhancement spectroscopy (NOESY).

https://www.jstage.jst.go.jp/article/cpb1958/43/2/43_2_223/_pdf

Arasuke Nishi

Papers

Isolation and antimicrobial activity of the phytoalexin 6-methoxymellein from cultured carrot cells

Physiological Changes of Carrot Cells in Suspension Culture during Growth and Senescence

Production and metabolism of 6-methoxymellein in cultured carrot cells

Partial Synchronization of Carrot Cell Culture by Auxin Deprivation

Studies on Metabolites of Mycoparasitic Fungi. II. Metabolites of Trichoderma koningii