Sorghum, condensed tannins

Janet T, Taylor JRN, Belton PS, Amanda M. KaUrin microparticle encapsulation of catechin and sorghum condensed tannins. J Agric Food Chem. 2009 57(16) 7523—7528. 

C. A possible structure of grain sorghum condensed tannin. 

Proanthocyanidins (PAs), also known as condensed tannins, are oligomeric and polymeric flavan-3-ols. Procyanidins are the main PAs in foods however, prodelphinidins and propelargonidins have also been identified (Gu and others 2004). The main food sources of total PAs are cinnamon, 8084 mg/100 g FW, and sorghum, 3937 mg/100 g FW. Other important sources of PAs are beans, red wine, nuts, and chocolate, their content ranging between 180 and 300 mg/100 g FW. In fruits, berries and plums are the major sources, with 213.6 and 199.9 mg/100 g FW, respectively. Apples and grapes are intermediate sources of PAs (60 to 90 mg/100 g FW), and the content of PAs in other fruits is less than 40 mg/100 g FW. In the majority of vegetables PAs are not detected, but they can be found in small concentrations in Indian squash (14.8 mg/ 100 g FW) (Gu and others, 2004 US Department of Agriculture, 2004). 

Condensed tannin (or procyanidin polymer) from seed coat of sorghum. n=4-5. M, 17(X)-2000... 

The condensed tannins are not readily degraded by acid treatment but polymerize to form amorphous phlobaphenes or tannin-reds (Haslam, 1966). A typical structure of a condensed tannin isolated from sorghum is shown in Fig. 3 (Haslam, 1977). 

Jimenez-Ramsey L, Rogler JC, Housley TL, Butler LG, Elkin RG (1994) Absorption and distribution of C-labeled condensed tannins and related Sorghum phenolics in chickens. J Agric Food... 

Type II or Red or This is the most popular sorghum class worldwide. Morphologically, it contains Yellow a testa but is not pigmented therefa"e does not possess condensed tannins. 

Tannins Astringent condensed polyphenolic compounds present in some cereals such as bird-resistant sorghums that are antinutritional because they bind digestive enzymes and dietary proteins lowering feed efficiency. Tannins are also antimicrobial and prevent grain from sprouting in the field. Today, tannins are viewed as potent antioxidants and nutraceuticals. The tannins associated with hops bind proteins, decreasing beer haze and, upon oxidation, form colored compounds necessary in beer. 

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