Total phenolic compounds

The effect of storage temperatures on total phenol compounds on strawberry fruit has been also reported (Ayala-Zavala and others 2004). Total phenol compounds increased in berries stored at 5°C and 10°C (Fig. 11.1, II). However, strawberry fruit stored at 0°C maintained a constant value of total phenol compounds during the storage period. Both temperature and storage time had a significant effect on total phenol compounds of strawberry fruits (Ayala-Zavala and others 2004). 

El-Morsi, E. A., Abdel-Naem, G. R, Shaker, E. S., Ghazy, M. A. (2000). Influence of biofertilization on total phenolic compounds and antioxidative activity of potato tubers (Solanum tuberosum L.). Arab Univ J Agric Sci,8, 1-18. 

Quantitative Analysis of Tannins. Beginning with determinations for total phenolic compounds, all attempts to isolate compounds related to tannins—i.e., those forming stable compounds with proteins—have been unsatisfactory. Hence, one cannot use this as the basis for an analytical method. 

Several studies have described a relationship between the activity of PAL in iceberg lettuce leaf tissue and the development of RS symptoms [141-146]. Hyodo et al. [141] observed that an ethylene-induced increase in PAL activity parallelled the appearance of RS symptoms. These researchers also measured an increase in total phenolic compounds. It has been proposed that ethylene induces PAL activity and the resulting accumulation of phenolic compounds in cells leads to their discoloration and eventual death [141,143,145]. 

The total phenolic compounds in an aqueous sample can be determined by a colorimetric method using 4-aminoantipyrine. This reagent reacts with phenolic compounds at pH 8 in the presence of potassium ferricyanide to form a colored antipyrine dye, the absorbance of which is measured at 500 nm. The antipyrine dye may also be extracted from the aqueous solution by chloroform. The absorbance of the chloroform extract is measured at 460 nm. The sample may be distilled before analysis for the removal of interfering nonvolatile compounds. The above colorimetric method determines only ortho- and meta-substituted phenols and not all phenols. When the pH is properly adjusted, certain para-substituted phenols, which include methoxyl-, halogen-, carboxyl-, and sulfonic acid substituents, may be analyzed too. 

Total phenolic compounds content was assayed spectrophotometri-cally using a modified Prussian blue method as described by Graham (28) employing an LKB Biochrom Ultrospec II spectrophotometer (Cambridge, England). Tannic acid was used as calibration standard. 

Aliphatic acids content and total phenolic compounds did not change significantly with severity and were omitted from the table. 

Fig. 2. Yield of inhibitory byproducts after dilute-acid hydrolysis of BSG as a function of CS. (O), Acetic acid (O), furfural ( ), HMF ( ), formic acid (—), levulinic acid ( ), total phenolic compounds. The lines only show trends.

From the reported data (Figs. 1 and 2, Table 1) the optimum condition to obtain a pentose-rich hydrolysate from dilute-acid hydrolysis of BSG at 130°C was 15 min (CS 1.94). Such hydrolysate contains about 43.5 g/L of glucose, xylose, and arabinose (ratio of 10 67 32), together with a low content of furfural, HMF, acetic acid, formic acid, and total phenolic compounds (Table 2). This condition was chosen for subsequent production of hydrolysates for fermentation. 

Determination of Total Phenolic Compounds in by the Folin-Ciocalteu Index... 

The waste spent sulfite pulping liqpior (SSL) had a high solid content, so dilution was necessary before fermentation. The 50% SSL after dilution to 15% wlw contained 2.04 g/1 glucose 4.69 g/1 maimose 0.94 g/1 arabinose 2.83 g/1 xylose 1.25 g/1 galactose, and 11.2 g/1 total phenolic compounds. 

Goli, A.H., Barzegar, M., and Sahari, M.A., Antioxidant activity and total phenolic compounds of pistachio (Pistachia vera) hull extracts, Food Chem., 92, 521-525, 2005. 

Extracts of different grapes were tested for their antioxidant activities in a copper-catalysed lecithin liposome system (Table 9.16). Extracts of red wine grape varieties contained higher concentrations of total phenolic compounds and higher relative antioxidant activities (67-1 (X)%) than the white wine and table grapes (25-27%). The relative percent inhibition of conjugated dienes and hexanal correlated with total phenols. Anthocyanins were the most abundant... 

Fig. 2. Relationships between the content of total phenolic compounds and the degree of astrin-gency based on organoleptic tests in peach firuit, p = 0.05...

Kubota N, Shimamura K, Mimura H, Nakano M (1986) Changes in the content of total phenolic compound during fruit ripening of peaches as affected by different rootstocks. HortScience 21 765 (Abstr 774)... 

H.M. Oliveira, M.A. Segundo, S. Reis, J.L.F.C. Lima, Multi-syringe flow injection system with in-line preconcentration for the determination of total phenolic compounds, Microchim. Acta 150 (2005) 187-196. 

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