Polyphenols classes

Figure 11.3.11 Sample UV spectra from various polyphenolics classes (A) cinnamic acid (a phenolic acid), (B) cyanidin (an anthocyanidin), (C) catechin (a flavan-3-ol), and (D) quercetin (a flavonol). AU, absorbance units.

We must be cautious about what conclusions we draw from new research on polyphenols in relation to superfruits. The polyphenol class as a whole is a highly productive research topic in food and medical science. While scientists are continually adding to what we know about the possible impact of these plant compounds on human health, we need to be wary about the use of unconfirmed results for marketing by manufacturers eager to have a competitive edge in selling superfruit products. This practice unfortunately leads to false claims of effectiveness and to their acceptance by consumers as fact when actually the research is too premature to warrant conclusions about health benefits. 

Fortified soy milk rather than dairy milk. I choose fortified soy products because they have higher contents of micronutrients, heart-healthy omega fats, sterols, and a polyphenol class called isoflavones, which also may be beneficial. These features are not present comparatively in dairy milk. Protein and carbohydrate levels are about the same between soy and dairy milks, but adequate content of these macronutrients is supplied by the superfruits you choose. Also, if you are fond of vanilla, as I am, most brands of soy milk include a vanilla-flavored product that goes well with fruits. 

The number of studies presenting HSCCC or CPC applications for the purification of phenolic compounds remains low as compared to other classes of secondary metabolites like alkaloids. However, the increasing number of papers published the last 5 years confirms the potential of these techniques for the separation and purification of different polyphenol classes including fiavonoids and phenolic acids. 

Lee, C.H., Reed, J.D. and Riehards, M.P. (2006). Ability of various polyphenolic classes from cranberry to inhibit lipid oxidation in mechanieally separated turkey and cooked groimd pork. Journal of Muscle Foods, 17, 248-266. 

Biological activity (BA) was chosen as such parameter. The BA determined using a system and a technique for a class of natural polyphenolic bonds nicotinamide adenine dinucleotide restored (NAD H ) - ferricyanide (KjFe(CN)g) in a phosphates buffer solution. 

Dietary consumption of polyphenols is associated with a lower risk of degenerative diseases. In particular, protection of serum lipids from oxidation, which is a major step in the development of arteriosclerosis, has been demonstrated. More recently, new avenues have been explored in the capacity of polyphenols to interact with the expression of the human genetic potential. The understanding of the interaction between this heterogeneous class of compounds and cellular responses, due either to their ability to interplay in the cellular antioxidant network or directly to affect gene expression, has increased. 

The use of HPLC for quantification of phenols is often limited to a single class of phenolics and then often only to low-molecular weight compounds that are available as standards. It is, therefore, often necessary to use colorimetric assays such as the Folin-Ciocalteau assay which rely on the reducing ability of phenols to quantify the amount of total phenolics in a sample (Waterman and Mole, 1994 Singleton et al, 1999 Schofield et al, 2001). The degree of condensation of polyphenols can be quantified by colorimetric assays such as the acid-butanol assay and the vanillin assay (Waterman and Mole, 1994 Schofield et al, 2001). 

Recent scientific investigations of natural polyphenols have demonstrated their powerful antioxidant property (Niki et al, 1995). Several classes of polyphenols have been chemically identified. Some of these are grape polyphenols, tea polyphenols, soy polyphenols, oligomeric proanthocyanidines (OPA) and other natural polyphenols of the flavone class. Rice bran polyphenols are different from the above in that they are p-hydroxy cinnamic acid derivatives such as p-coumaric acid, ferulic acid and p-sinapic acid. Tricin, a flavone derivative, has also been isolated from rice bran. 

Reboul, E, Thap, S, Toumiaire, F, Andre, M, Juhel, C, Morange, S, Amiot, MJ, Lairon, D, and Borel, P, 2007b. Differential effect of dietary antioxidant classes (carotenoids, polyphenols, vitamins C and E) on lutein absorption. Br J Nutr 97, 440-446. 

Polyphenols, as one of the largest and most widespread class of plant compounds, are also present in saffron stigma. In the mass spectrum of the flavonoid fraction of the methanolic extract from saffron there were ions at m/z 611 and 633 which may be attributed to protonated and sodiated quasi-molecular ions of kaempferol diglycoside. [22] Flavonoids from the water extract can be isolated and concentrated... 

The laccases, classed as polyphenol oxidases, catalyze the oxidation of diphenols, polyamines, as well as some inorganic ions, coupled to the four-electron reduction of oxygen to water see Fig. 12.4 for the proposed catalytic cycle. Due to this broad specificity, and the recognition that this specificity can be extended by the use of redox mediators [27], laccases show promise in a range of applications [28], from biosensors [29-32], biobleaching [27, 33-35] or biodegradation [36], to biocatalytic fuel cells [1-3, 18, 26, 37-42]. 

Polyphenols are the most abundant antioxidants in human diets. They are secondary metabolites of plants. These compounds are designed with an aromatic ring carrying one or more hydroxyl moieties. Several classes can be considered according to the number of phenol rings and to the structural elements that bind these rings. 

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