Grapes and berries

Grapes and berries are rich sources of phytochemicals including phenolic compounds, pigments, and ascorbic acid. 

Antioxidant Activity of Grapes and Berries and Their Products. 107... 

FIGURE 3.2 Structure of anthocyanidins occurring in grapes and berry fruits. [Source Adapted from Jovanovic et al. (1998) and Mazza and Miniati (1993).]... 

There are six anthocyanidins commonly occurring in grapes and berry fruits. The anthocyanidins are classified according to the number and position of their hydroxyl and methoxyl groups on the flavan nucleus and are named pelargonidin, cyanidin, delphinidin, peonidin, petunidin and malvidin (Figure 3.2). 

Flavanols with the hydroxyl group in the 3-position are often referred to as flavan-3-ols or catechins (Chung et al., 1998). As these compounds have two asymmetric carbon atoms (C-2 and C-3), four isomers exist for each flavan-3-ol molecule [Figure 3.3(b)], The flavan-3-ols most often occurring in grapes and berry fruits are... 

Anthocyanins in grapes and berry fruits have been of interest to scientists and food technologists for a long time due to their important contributions to color and... 

Anthocyanin Content in Selected Grapes and Berry Fruits... 

Total Phenolics (as Gallic Acid Equivalents, GAEs) in Selected Grapes and Berries... 

Substitution patterns of the flavan nucleus along with glycosidation and acylation patterns influence anthocyanin stability of grapes and berry fruits to some extent. 

Condensed tannins, the polymerized products of flavan-3-ols and flavan-3,4-diols, form complexes with proteins, starch and digestive enzymes and may cause a reduction in the nutritional value of foods (Chung et al 1998). In fruit extracts, the tannins may cause precipitation in the presence of proteins. The high ability of the condensed tannins to form complexes with other food components reduces the extractability of those constituents from grapes and berries. 

Extensive reviews of analytical methods for anthocyanins (Francis, 1982 Jackman et al., 1987b Strack and Wray, 1994) and other flavonoids (Williams and Harbome, 1994) as well as phenolic acids (Herrmann, 1989) have been published. In these reviews, extraction procedures, methods for fractionation of groups of polyphenols and the identification and quantification of individual components are presented. Here, a brief presentation of more recently published methods for grape and berry polyphenolic analyses is given with respect to their relationship to antioxidant activity and health benefits. 

The phenolics of grapes and berry fruits constitute a large group of compounds with various structural complexities. Thus, total phenolics encompass the more simple phenolic acids along with the various classes of flavonoids, some occurring... 

Due to the different methods used for evaluating antioxidant capacity of flavonoid from grapes and berries, direct comparisons between various species and products often cannot be made. However, a wide range of berry extracts, wines and juices... 

ORAC Values (pmol Trolox Equivalents/g Fresh Fruit) of Selected Grapes and Berry Fruits... 

Grapes and berry fruits are rich sources of flavonoids and polyphenolics. Labor-intensive investigations over the years, initially from botanists and later from chemists and food scientists, provide a vast amount of knowledge about chemical structure, occurrence and stability of these compounds. As a consequence, food products, extracts, tinctures and dry powders are available with documented levels of flavonoids and other phenolics. 

Simultaneous with the in vitro research, reports are appearing from the nutritional and human medical areas focusing on bioavailability of flavonoids and the importance of dietary antioxidants in preventing diseases such as coronary heart disease, cancer, vision deterioration and aging in vivo. When these two approaches meet in the hopefully not-too-distant future, the results should reveal scientifically sound conclusions regarding the health benefits of flavonoids. Although there is still much to be learned, there are indications that the scientific approach may reaffirm the basis for many of the remedies known from traditional therapeutic use of grape and berry products in folk medicine. 

Some horticultural specialties include growing grapes and berries for wine, aquatic gardening, and producing unusual species such as carnivorous plants, cacti and succulents, and bonsai and dwarf varieties. Flower growers often specialize in one species such as roses, orchids, or lilies. 

Moreover, two recent works report the capacity of dietary anthocyanins from grape and berries to reach the brain [69, 72]. 

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