Phenolic acid content

Table 1 Total phenolics and phenolic acids content (pg/g) in dry Rubus hirtus leaves determined by two different methods...

Truong VD, McFeeters RF, Thompson RT, Dean LL and Shofran B. 2007. Phenolic acid content and composition in leaves and roots of common commercial sweetpotato (Ipomea batatas L.) cultivars in the United States. J Food Sci 72(6) C343-C349. 

Table 6.5 Effect of potato size on the phenolic acid content of the peel and flesh of potatoes. ...

Table 6.6 lists the phenolic acid content of 25 potato powders prepared by lyophilization of commercial potatoes with unknown history. For the dry lyophilized powders, the data show that chlorogenic acid levels (in mg/lOOg wt) ranged from 3.28 for Kenebec potatoes to 637 for... 

The cited observations suggest that it is possible to identify potato cultivars with low or high phenolic acid content for human use and to select processing conditions that minimize losses of phenolic compounds. In summary, the methods we developed and used to determine the content and distribution of phenolic compounds in potato plant flowers, leaves, and tubers, in the peel and flesh parts of potato tubers, and in freeze-dried and processed commercial potatoes merit application in numerous studies designed to assess the role of potato phenolic compounds in host-plant resistance, plant breeding, plant molecular biology, food chemistry, nutrition, and medicine. The described wide distribution of phenolic compounds in different commercial... 

PHENOLIC ACID CONTENTS (G/KG) OF WHOLE AND DEHULLED FLAXSEED" 4... 

In an investigation by Martens (2000), alkaline extraction of HA was employed on a control soil, a corn-amended soil (high phenolic acids content), and canola residue amended soil (low phenolic acid content) after incubation for 29 and 84 days. It was found that the extractable HA in the nonamended soil maintained 2.8 g kg-1 soil during incubation, while in the corn-amended soil the HA increased to 3.3 gkg-1 soil (day 29) and 3.6gkg 1 soil (day 84). Incubation of the canola residue resulted in 2.8 g HA kg-1 (day 29) but a decrease of HA to 2.0 g kg-1 soil was observed after 84 days of incubation, suggesting that the canola residue addition resulted in an increased decomposition of native SOM. 

Blum, U., Wentworth, T. R., Klein, K., Worsham A. D., King L. D., Gerig, T. M., and Lyu S. W. 1991. Phenolic acid content in soil from wheat-no till, wheat-conventional till, and fallow-conventional till soybean cropping systems. J. Chem. Ecol. 17, 1045-1067... 

Holtekjolen, A.K. Kinitz, C. Knutsen, S.H. 2006. Flavanol and bound phenolic acid contents in different barley varieties. J. Agric. Food Chem. 54 2253-2260. 

Black raspberries are not included among the top twenty superfruits because they contain higher phenolic acid contents, are therefore sour if not bitter in taste, and are generally not enjoyed as much for fresh eating as the red species. Also, there is a limited supply of black raspberries in North America as this species has not been well crossbred to increase its resistance to plant diseases. Accordingly, farmers have not invested in black raspberries as a plant with higher disease risk and lower yield. 

The titration vessel was purged with nitrogen to eliminate CO 2. From the volume and molarity of added base and the mass of titrated DOC, the content of acidic functional groups can be calculated. Carboxylic acid content was calculated from the amount of base added until the end-point was reached. Phenolic acid content was calculated as twice the difference in titrant required to change the pH of the titrate from 8 to 10, since it was assumed that at pH 10 only half the phenolic groups were dissociated. A solution of a concentration of 20 mgL" as DOC NOM were titrated. The error due to the salt content of NOM is likely to be high. 

The phenolic acid content of vegetables of the genus Brassica consists almost totally of hydroxycinnamic acid compounds, of which, unlike in other species of vegetables, sinapic acid is the predominant one [55] (Table 3). 

Table 3. Phenolic Acid Content of Brasicaceae Vegetables. Values are mg/kg Fresh Weight (Table Modified from [55]).

The yeast strain also plays an essential role in determining the volatile phenol concentration in white wines. For many years now in the brewing industry (Goodey and Tubb, 1982), yeast strains have been selected for their low production of vinyl-phenols, as malt has a high phenol acid content. These are called Pof- (phenol off-flavor) strains. The selection of winemaking yeast has... 

Wanasundara and Shahidi (1994a) reported that the total content of phenolic acids of flaxseed meal was about 220 mg/lOOg, on a dry weight basis. Methanol-ammonia-water/hexane extraction lowered the total phenolic acid content of the meals by approximately 48%. The content of condensed tannins of flaxseed meal was about 136 mg/lOOg, determined as (+)catechin equivalents, and this must have originated from the seed coat. The two-phase solvent extraction system (methanol-ammonia-water/hexane) reduced the content of tannins in the meal by 74% (Wanasundara and Shahidi, 1994a). 

Plant antioxidant activity is due to phenolic acid content, especially caffeic and p-coumaric. The greater antioxidant activity of caffeic acid than p-coumaric acid stems from the 3,4-position of dUiydroxylation on the phenolic ring [33]. 

Gruz J, Ayaz FA, Torun H, Strand M (2011) Phenolic acid content and radical scavenging activity of extracts from medlar (Mespilus germanica L.) fruit at different stages of ripening. Food Chem 124 271... 

L6pez-Raez JA, Flors V, Garcia JM, Pozo MJ (2010) AM symbiosis alters phenolic acid content in tomato roots. Plant Signal Behav 5 1138-1140... 

To determine soil phenolic acid content, 50-75 g soil subsamples were placed in 500 ml Erlenmeyer flasks with 100 ml deionized water. Loosely capped flasks were autoclaved (liquid cycle) for 45 min at 1.2 kg/cm and 2 °C, removed from the autoclave, and allowed to come to room temperature (20-30 min). The slurry in the flask was then centrifuged for 10 min at 27,200 g. The resulting supernatant... 

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