Fruits total phenolics

ANCos B DE, GONZALES E M and CANO M p (2000) Ellagic acid, vitamin C, and total phenolic contents and radical scavenging capacity affected by freezing and frozen storage in raspberry fruit , J Agric Food Chem, 48 (10) 4565-70. 

Velioglu YS, Mazza G, Gao L and Oomah DB. 1998. Antioxidant activity and total phenolics in selected fruits, vegetables, and grain products. J Agric Food Chem 46 4113—4117. 

Rababah, TM, Ereifej, KI and Howard, L. 2005. Effect of ascorbic acid and dehydration on concentrations of total phenolics, antioxidant capacity, anthocyanins, and color in fruits. J Agric Food Chem 53(ll) 4444-4447. 

Figure 11.1. Effect of storage temperature (0, 5, 10°C) on (I) total anthocyanins (mg/100 g FW), (II) total phenols (mg/100 g FW), and (III) antioxidant capacity measured as ORAC (p.mol TE/g FW) of strawberry fruit (cv. Chandler). Bars show the final values after treatments. Different letters on top of the bars indicate statistical differences among treatments (p < 0.05).

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). 

It has been observed that treatment with natural antimicrobial volatiles also affected the antioxidant capacity of fruits (Ayala-Zavala and others 2005). ORAC values of control strawberries changed during storage at 7.5°C (Fig. 11.3, III). However, significant increases in antioxidant capacity values were observed in strawberries treated with methyl jasmonate, methyl jasmonate-ethanol, and ethanol. One explanation for this difference could be associated with differences on total phenol content (Ayala-Zavala and others 2005). 

A similar effect was observed in other fruits and vegetables, where UV-C treated strawberries showed a higher increment of phenols and PAL activity 12 hours after treatment than unirradiated (control)(Pan and others 2004), which could be the reason for the increment in total phenol constituents (Lancaster and others 2000). UV-C and UV-B caused a two- and threefold increase in content of resveratrol (a grape phenol constituent). Thus, mature Napoleon grapes that had been irradiated with UV-C light can provide up to 3 mg of resveratrol per serving (Cantos and others 2001). Therefore, UV-C treatments clearly cause a benefit effect, increasing total phenol content, which can be mainly attributed to the increment of PAL activity. 

The colorimetric method based on the reagents of Folin and Denis or of Folin and Ciocalteu has been generally preferred over other methods to determine total phenols in complex natural materials such as wines and fruits (1, 2, 3, 4, 5). This method is relatively simple, convenient, reliable, generally applicable, and it is accepted as an official analysis in several countries for total phenols in wines and a number of other products. Although it is a preferred method, it can be even better than is commonly recognized. 

Amine and Aminophenol Derivatives. Amines and aminophenols (Table VIII) react with the F-C reagent about as predicted considering the aromatic amino groups equivalent to phenolic hydroxyls. This would be an important interference with total phenol assay in samples with appreciable aromatic amine content. Fortunately, for this and other reasons as well, the major wine grapes and most other fruit and vegetable products are free of significant concentrations of aromatic amines which would interfere. Correction might be made for methyl anthranilate... 

Determination of total phenols in wastewaters using a biosensor based on carbon paste modified with crude extract of jack fruit (Artocarpus integrifolia L.)... 

The developed biosensor based on graphite/capric acid modified with PPO from jack fruit crude extract was sensitive, of easy construction and reliable in determining total phenols in wastewater samples. The results of the proposed method agreed at the 95% confidence level with the results obtained using the standard method procedure. 

Immature and ripe fruits of Japanese hot and sweet peppers were analysed for total phenolic, flavonoid and capsaicinoid contents. The amount of phenolic compounds was higher in hot and ripe pepper fruits than in sweet and immature pepper fruits. Capsaicinoids, which were detected in hot peppers only, were highest in immature and ripe fruits. The data reveal that the total phe-nolics content is a good indicator of the antioxidant activity of pepper fruits and that the antioxidant levels in sweet peppers, especially in the ripe fruits, are higher than they are in hot peppers (Saga and Sato, 2003). 

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... 

Wang and Lin (2000) measured antioxidant activity (ORAC) and total phenolic and anthocyanin contents of thornless blackberry, strawberry and red and black raspberry fruits and found linear relationships between both ORAC and total phenolics and between ORAC and anthocyanins of ripe fruits. Spray-dried elderberry juice with high amounts of anthocyanin glucosides caused prolongation of the lag-phase for Cu-induced oxidation of human LDL, while the maximum oxidation rate remained unchanged (Abuja et al., 1998). For peroxyl-radical-driven LDL oxidation, however, both prolongation of lag time and reduction of maximum oxidation rate occurred. 

Prior et al. (1998) reported that ORAC values of blueberries increased with maturity of the fruits, while various growing places throughout the United States did not affect the ORAC values. A linear relationship between ORAC values, i.e., antioxidant capacity as determined by the ORAC method, was obtained with the anthocyanin (rxy = 0.77) and total phenolics (rxv = 0.92) content. 

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