Antioxidant and Phenolics: Strawberries

High performance liquid chromatography coupled with diode array and coulometric array detectors were used to characterize and quantify phenolic compounds in achenes and flesh of ripe strawberries (cv Totem and Puget Reliance). Total phenolics and total monomeric anthocyanins were measured and antioxidant activities were evaluated by the FRAP and the ORAC assays. Strawberries contained 1% achenes on a fresh weight basis; however, they contributed to about 11% of total phenolics and 14% of antioxidant activities in strawberries. Ellagic acid, ellagic acid glycosides, and ellagitannins were the main contributors to the antioxidant activities of achenes. The major anthocyanin in flesh was pelargonidin-3-glucoside, whereas achenes consisted of nearly equal amounts of cyanidin-3-glucoside and pelargonidin-3-glucoside. Phenolic content and antioxidant activity of strawberry achenes were reduced by industrial processing. However, the levels were still high and strawberry waste byproduct could thus be a possible source of nutraceuticals or natural antioxidants.

Three strawberry cultivars ( Dover , Campineiro, and Oso Grande), grown in the same commercial plantation, were harvested at the ripe stage and stored at 6, 16 and 25 °C, for 6 days. During this period, chemical composition and antioxidant activity were evaluated. Results showed an increase in total soluble sugars, anthocyanin and vitamin C contents, indicating that a new biosynthesis had taken place during storage. Low temperature negatively affected anthocyanin and vitamin C accumulation, and positively affected soluble sugars, while flavonols, ellagic acid and total phenolic contents remained almost the same or even decreased at all temperatures. Despite differences in anthocyanin content between varieties and its increase during storage (higher with increasing temperature), there was no difference in the antioxidant activity between cultivars, which decreased after harvesting, independently of the temperature of storage. Variations in the proportion dehydroascorbic acid/ascorbic acid (DHA/AA) showed that there were differences between cultivars concerning adaptation of the fruit to low temperatures. The data obtained here indicate that cold storage is an effective way to maintain strawberry quality, but a compromise between sensorial and nutritional values can be achieved at 16 °C, for all the cultivars.

Ellagitannins (ETs) are dietary polyphenols, containing ellagic acid (EA) subunits, with antioxidant and cancer chemopreventive activities that might contribute to health benefits in humans. However, little is known about their metabolic fate. We investigate here the metabolism of different dietary ETs and EA derivatives in humans. Forty healthy volunteers were distributed in four groups. Each group consumed, in a single dose, a different ET-containing foodstuff, i.e., strawberries (250 g), red raspberries (225 g), walnuts (35 g), and oak-aged red wine (300 mL). After the intake, five urine fractions (F) were collected at 8 (F1), 16 (F2), 32 (F3), 40 (F4), and 56 (F5) h. Neither ETs nor EA were detected in urine after LC-MS/MS analysis. However, the microbial metabolite 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one (urolithin B) conjugated with glucuronic acid was detected along the fractions F3-F5 in all of the subjects, independently of the consumed foodstuff. The mean percentage of metabolite excretion ranged from 2.8 (strawberries) to 16.6% (walnuts) regarding the ingested ETs. Considerable interindividual differences were noted, identifying "high and low metabolite excreters" in each group, which supported the involvement of the colonic microflora in ET metabolism. These results indicate that urolithin B (a previously described antiangiogenic and hyaluronidase inhibitor compound) is a biomarker of human exposure to dietary ETs and may be useful in intervention studies with ET-containing products. The antioxidant and anticarcinogenic effects of dietary ETs and EA should be considered in the gastrointestinal tract whereas the study of potential systemic activities should be focused on the bioavailable urolithin B derivatives.

Jam was prepared from five strawberry cultivars; ‘Senga Sengana’, ‘Korona’, ‘Polka’, ‘Honeoye’ and ‘Inga’. The jam was stored at 4 and 20 1C, in darkness and under fluorescent light (950 lux). The quality parameters assessed were colour reflectance at 650 nm, Hunter L; a; b, anthocyanin pigments and total antioxidant capacity assessed by FRAP-assay. Jam produced of all cultivars stored at 4 1C had significantly better colour qualities and FRAP-values than jam stored at 20 1C. The light conditions during storage did not affect the assessed quality parameters of the product during three months of storage. The cultivars ‘Senga Sengana’, ‘Korona’, ‘Honeoye’ and ‘Polka’ showed the highest a*-values (red colour), but only ‘Korona’, ‘Honeoye’ and ‘Polka’ showed a high total antioxidant capacity, as measured by FRAP and compared to ‘Senga Sengana’ and ‘Inga’. Thus, to achieve a good coloured strawberry jam with high antioxidant capacity, the industry should consider to store the products at 4 1C and to replace ‘Senga Sengana’ with one of the ‘Korona’, ‘Honeoye’ and ‘Polka’ cultivars. 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Three strawberry cultivars (Dover, Campineiro, and Oso Grande), grown in the same commercial plantation, were harvested at the ripe stage and stored at 6, 16 and 25 °C, for 6 days. During this period, chemical composition and antioxidant activity were evaluated. Results showed an increase in total soluble sugars, anthocyanin and vitamin C contents, indicating that a new biosynthesis had taken place during storage. Low temperature negatively affected anthocyanin and vitamin C accumulation, and positively affected soluble sugars, while flavonols, ellagic acid and total phenolic contents remained almost the same or even decreased at all temperatures. Despite differences in anthocyanin content between varieties and its increase during storage (higher with increasing temperature), there was no difference in the antioxidant activity between cultivars, which decreased after harvesting, independently of the temperature of storage. Variations in the proportion dehydroascorbic acid/ascorbic acid (DHA/AA) showed that there were differences between cultivars concerning adaptation of the fruit to low temperatures. The data obtained here indicate that cold storage is an effective way to maintain strawberry quality, but a compromise between sensorial and nutritional values can be achieved at 16 °C, for all the cultivars.

Four cultivars of strawberries (Senga Sengana, BFr77111, Elsanta, and Honeoye) were studied for their content of antioxidants, total antioxidant capacity, and low molecular weight carbohydrates in relation to harvest year, ripening stage, and cold storage. For ascorbic acid, chlorogenic acid, ellagic acid, and total antioxidative capacity, measured in both water-soluble and water-insoluble extracts, there was a 2-5-fold variation among cultivars. Unripe berries contained lower concentrations of chlorogenic acid and p-coumaric acid and also quercetin and kaempferol compared with riper berries. During cold storage for up to 3 days, relatively few changes in the concentration of the different antioxidants occurred. The concentrations of several investigated parameters were interrelated, for example, for ascorbic acid and water-soluble antioxidant capacity and for ellagic acid and water-insoluble antioxidant capacity. The dominating sugars in strawberries were fructose and glucose, but considerable amounts of sucrose were also present, and their contents varied among cultivars, giving a predicted glycemic index of ~81. Verbascose, raffinose, and stachyose were found in only minor amounts. The study shows that the concentration of a number of bioactive compounds in strawberries varied according to cultivar, ripening stage, and storage. This information should make it possible to select strawberries with an optimal content of bioactive compounds.

The antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC), total anthocyanin, total phenolic, aroma compounds, and postharvest quality of strawberry fruit (Fragaria x ananassa cv. Chandler) kept at 0, 5 and 10C were investigated. Strawberry fruit stored at 10 or 5C showed higher antioxidant capacity, total phenolic, and anthocyanins than those stored at 0C. However, the postharvest life based on overall quality was longer at 0C than at 5 or 10C. The production of aroma compounds was markedly influenced by storage time and temperature. Individual aroma compounds were affected differently. For example, ethyl hexanoate, hexyl acetate, methyl acetate, and butyl acetate increased, while 3-hexenyl acetate and methyl hexanoate decreased during storage. In general, strawberries stored at 10 or 5C produced higher levels of these volatiles than those stored at 0C. In conclusion, strawberries stored at 0C retained an acceptable overall quality for longest storage duration, however, berries stored at temperatures higher than 0C showed higher aroma compounds and antioxidant capacity during the postharvest period.

Strawberries contain high levels of antioxidants, which have been correlated with a decreased risk of chronic disease. To more fully characterize the antioxidant profiles and possible associated health benefits of this fruit, the total free and bound phenolic, total flavonoid, and total anthocyanin contents of eight strawberry cultivars (Earliglow, Annapolis, Evangeline, Allstar, Sable, Sparkle, Jewel, and Mesabi) were measured. Cultivar effects on phenolic contents were compared with antioxidant capacities, as measured by the total oxyradical scavenging capacity (TOSC) assay, and to antiproliferative activities, as measured by inhibition of HepG2 human liver cancer cell proliferation in vitro. Free phenolic contents differed by 65% between the highest (Earliglow) and the lowest (Allstar) ranked cultivars. The water soluble bound and ethyl acetate soluble bound phenolic contents averaged 5% of the total phenolic content of the cultivars. The total flavonoid content of Annapolis was 2-fold higher than that of Allstar, which had the lowest content. The anthocyanin content of the highest ranked cultivar, Evangeline, was more than double that of the lowest ranked cultivar, Allstar. Overall, free phenolic content was weakly correlated with total antioxidant activity, and flavonoid and anthocyanin content did not correlate with total antioxidant activity. The proliferation of HepG2 human liver cancer cells was significantly inhibited in a dose-dependent manner after exposure to all strawberry cultivar extracts, with Earliglow exhibiting the highest antiproliferative activity and Annapolis exhibiting the lowest. No relationship was found between antiproliferative activity and antioxidant content.

Strawberries are one of the best natural sources of antioxidants, chemical substances that are much needed in our body’s fight with damaging free radicals. Vitamin C and E are essential antioxidants, however, non-essential phytochemical antioxidants such as phenolic compounds in strawberries have been increasingly found to be even stronger antioxidants. They have also been found to work synergistically with the vitamins in the elimination of free radicals. Many different phenolic compounds are found in strawberries. Anthocyanidins, procyanidins, phenolic acids and flavonoids are among the most important of these chemicals. However, the concentration and composition of these phytochemicals vary depending on the variety, location of cultivation and growing seasons. Several dozens of different cultivated and wild strawberry plants were examined over three years, and we found that the average total phenolic content of wild strawberries were much higher than those of the cultivated strawberries. By using three different in vitro antioxidant assays, extracts of strawberries were found to be better antioxidants than the commercial antioxidant, BHT, used in food at the recommended concentration. The antioxidant activity of the strawberry is attributed to the phenolic compounds, which were also found to possess high antioxidant activity. Understanding the basic chemistry of the strawberry is the first step in the course of developing antioxidant nutraceuticals from strawberries. Phytochemical studies are important because they provide critical information on the individual antioxidant chemicals, which is needed for mode of action studies and for breeding high antioxidant strawberries for fresh consumption.

The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, 30/22 °C) on phenolic acid, flavonol, and anthocyanin content and their antioxidant activities against peroxyl radicals (ROO •), superoxide radicals (O2 •-), hydrogen peroxide (H2O2), hydroxyl radicals (OH •-), and singlet oxygen (1O2,) in fruit juice of ‘Earliglow’ and ‘Kent’ strawberry (Fragaria x ananassa Duch.) were studied. The content of cyanidin- based anthocyanins, were much lower than pelargonidin-based anthocyanins. High day/night temperature conditions significantly enhanced p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate and pelargonidin 3-glucoside-succinate content in strawberry juice. Plants grown at low day and night temperatures (18/12 °C) generally had the lowest anthocyanin contents. Plants grown at the highest day/night temperatures (30/22 °C) produced fruit with the most phenolic content as well as antioxidant capacity. Fruit of ‘Kent’ strawberry had higher contents of phenolic acid, flavonols, anthocyanins and antioxidant capacities compared to fruit of ‘Earliglow’ strawberry under all temperature regimes.

Plant regeneration through organogenesis of shoot bud from callus cultures of strawberry was established and three types of callus having different regeneration capacity were obtained. This experimental system was used to investigate the release of peroxide radicals and hydrogen peroxide, and the activities of antioxidant enzymes. H2O2 production coincided with emergence of meristemoid and formation of bud primordium in morphogenic calli. During the differentiation and development of callus, superoxide dismutase (SOD) activity increased in the early regeneration culture and decreased thereafter, and catalase activity constantly declined while peroxidase decreased during the 5-d culture and gradually increased thereafter. High O2.- level, low H2O2 level and nearly no SOD activity were detected in calli possessing low organogenesis capacity. N,N-diethyldithiocarbonate treatment decreased the regeneration percentage, while exogenous addition of H2O2 slightly promoted the potential for regeneration of shoot bud. The results suggest that H2O2 is correlated with the morphogenetic process in strawberry callus, and may actually serve as a messenger in the process of bud primordium formation.

Compost as a soil supplement significantly enhanced levels of ascorbic acid (AsA) and glutathione (GSH) and ratios of AsA/dehydroascorbic acid (DHAsA) and GSH/oxidized glutathione (GSSG) in fruit of two strawberry (Fragaria ¥ ananassa Duch.) cultivars, Allstar and Honeoye. The peroxyl radical (ROO) as well as the superoxide radical (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH), and singlet oxygen (1O2) absorbance capacity in strawberries increased significantly with increasing fertilizer strength and compost use. The planting medium (compost) ¥ fertilizer interaction for phenolics and flavonoids was significant. Fruit from plants grown in full-strength fertilizer with 50% soil plus 50% compost and 100% compost yielded fruit with the highest levels of phenolics, flavonol, and anthocyanin content. A positive relationship between antioxidant activities and contents of AsA and GSH and ratios of AsA/DHAsA and GSH/GSSG existed in fruit of both strawberry cultivars. Correlation coefficients for the content of antioxidant components versus antioxidant activity [against ROO, O2-, H2O2, OH, or 1O2] ranged from r = 0.7706 for H2O2 versus GSH/GSSH in cv. Allstar to r = 0.9832 for O2- versus total flavonoids in cv. Allstar.

The effects of elevated CO2 concentrations on the antioxidant capacity and flavonoid content in strawberry fruit (Fragaria x ananassa Duch.) were studied under field conditions. Increased CO2 (300 and 600 mol mol-1 above ambient) concentrations resulted in increases in ascorbic acid (AsA), glutathione (GSH), and ratios of AsA to dehydroascorbic acid (DHAsA) and GSH to oxidized glutathione (GSSG), and a decrease in DHAsA in strawberry fruit. High anthocyanin and phenolic content were also found in fruit of CO2 treated plants. Growing strawberry plants under CO2 enrichment conditions significantly enhanced fruit p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, and kaempferol 3-glucoside contents, as well as cyanidin 3-glucoside, pelargonidin 3-glucoside, and pelargonidin 3-glucoside-succinate content. Fruit of strawberry plants grown in the CO2 enrichment conditions also had high oxygen radical absorbance activity against ROO, O2-, H2O2, OH, and 1O2 radicals.

Plant regeneration through organogenesis of shoot bud from callus cultures of strawberry was established and three types of callus having different regeneration capacity were obtained. This experimental system was used to investigate the release of peroxide radicals and hydrogen peroxide, and the activities of antioxidant enzymes. H₂O₂ production coincided with emergence of meristemoid and formation of bud primordium in morphogenic calli. During the differentiation and development of callus, superoxide dismutase (SOD) activity increased in the early regeneration culture and decreased thereafter, and catalase activity constantly declined while peroxidase decreased during the 5-d culture and gradually increased thereafter. High O₂&unknown;^- level, low H₂O₂ level and nearly no SOD activity were detected in calli possessing low organogenesis capacity. N,N-diethyldithiocarbonate treatment decreased the regeneration percentage, while exogenous addition of H₂O₂ slightly promoted the potential for regeneration of shoot bud. The results suggest that H₂O₂ is correlated with the morphogenetic process in strawberry callus, and may actually serve as a messenger in the process of bud primordium formation.

Cultural system [hill plasticulture (HC) versus matted row (MR)] and genotype interactions affected strawberry fruit quality. In general, fruit soluble solids content, total sugar, fructose, glucose, ascorbic acid, titratable acid, and citric acid contents were increased in the HC system. Fruit from HC alsohad higher flavonoid contents and antioxidant capacities. Strawberry fruit contains flavonols as well as other phenolic compounds such as anthocyanins and phenolic acids. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside, pelargonidin 3-rutinoside, and pelargonidin 3-glucoside-succinate were the predominant anthocyanins in strawberry fruit. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins in either system. Strawberry fruit from the HC system had significantly higher amounts of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate. Fruits from plants grown in the MR system generally had the lowest contents of phenolic acids, flavonols, and anthocyanins. Strawberry fruit grown under HC conditions had significantly higher peroxyl radicals (ROO) absorbance capacity (ORAC).

Cultural system [hill plasticulture (HC) versus matted row (MR)] and genotype interactions affected strawberry fruit quality. In general, fruit soluble solids content, total sugar, fructose, glucose, ascorbic acid, titratable acid, and citric acid contents were increased in the HC system. Fruit from HC also had higher flavonoid contents and antioxidant capacities. Strawberry fruit contains flavonols as well as other phenolic compounds such as anthocyanins and phenolic acids. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside, pelargonidin 3-rutinoside, and pelargonidin 3-glucoside-succinate were the predominant anthocyanins in strawberry fruit. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins in either system. Strawberry fruit from the HC system had significantly higher amounts of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate. Fruits from plants grown in the MR system generally had the lowest contents of phenolic acids, flavonols, and anthocyanins. Strawberry fruit grown under HC conditions had significantly higher peroxyl radicals (ROO) absorbance capacity (ORAC).

In 1996 a new project established between Agriculture and Agri-Food Canada, Les Fraises de l' Île d'Orleans Inc. and McGill University to develop a new firm strawberry cultivars with long shelf life suitable for transportation. Five selections (FIO-9623-55, FIO-9524-74, FIO-968-1, FIO-9624-11, FIO-9623-40) were retained and entered into the advanced trials. FIO-9623-55 were reselected under the name ‘L’Authentique Orléans’ for its good shelf life, high yield and firm large fruit.

The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 C) on phenolic acid, flavonol, and anthocyanin content and their antioxidant activities against peroxyl radicals (ROO), superoxide radicals (O2-), hydrogen peroxide (H2O2), hydroxyl radicals (OH), and singlet oxygen (1O2) in fruit juice of Earliglow and Kent strawberry (Fragaria ¥ ananassa Duch.) cultivars was studied. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside (291.3-945.1 g/g fresh wt.), pelargonidin 3-rutinoside (24.7-50.9 g/g fresh wt.), and pelargonidin 3-glucoside-succinate (62.2-244.0 g/g fresh wt.) were the predominant anthocyanins in strawberry fruit juice. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins. Strawberry growth in high temperature conditions significantly enhanced the content of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate in strawberry juice. Plants grown in the cool day and cool night temperature (18/12 C) generally had the lowest phenolic acid, flavonols, and anthocyanins. An increase in night temperature from 12 to 22 C, with the day temperature kept constant at 25 C, resulted in a significant increase in phenolic acid, flavonols, and anthocyanins. These conditions also resulted in a significant increase in antioxidant capacity. The highest day/night temperature (30/22 C) yielded fruit with the most phenolic content as well as ROO, O2-, H2O2, OH, and 1O2 radical absorbance capacity. Fruit of Kent cv. strawberry had higher values of phenolic acid, flavonols, anthocyanins, and antioxidant capacities than fruit of Earliglow cv. strawberry under all temperature regimes.

The influence of four day/night growing temperature combinations (18/12, 25/12, 25/22, and 30/22 C) on phenolic acid, flavonol, and anthocyanin content and their antioxidant activities against peroxyl radicals (ROO), superoxide radicals (O2-), hydrogen peroxide (H2O2), hydroxyl radicals (OH), and singlet oxygen (1O2) in fruit juice of Earliglow and Kent strawberry (Fragaria ¥ ananassa Duch.) cultivars was studied. Pelargonidin-based anthocyanins such as pelargonidin 3-glucoside (291.3-945.1 g/g fresh wt.), pelargonidin 3-rutinoside (24.7-50.9 g/g fresh wt.), and pelargonidin 3-glucoside-succinate (62.2-244.0 g/g fresh wt.) were the predominant anthocyanins in strawberry fruit juice. The content of cyanidin-based anthocyanins, cyanidin 3-glucoside and cyanidin 3-glucoside-succinate, was much lower than that of pelargonidin-based anthocyanins. Strawberry growth in high temperature conditions significantly enhanced the content of p-coumaroylglucose, dihydroflavonol, quercetin 3-glucoside, quercetin 3-glucuronide, kaempferol 3-glucoside, kaempferol 3-glucuronide, cyanidin 3-glucoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside, cyanidin 3-glucoside-succinate, and pelargonidin 3-glucoside-succinate in strawberry juice. Plants grown in the cool day and cool night temperature (18/12 C) generally had the lowest phenolic acid, flavonols, and anthocyanins. An increase in night temperature from 12 to 22 C, with the day temperature kept constant at 25 C, resulted in a significant increase in phenolic acid, flavonols, and anthocyanins. These conditions also resulted in a significant increase in antioxidant capacity. The highest day/night temperature (30/22 C) yielded fruit with the most phenolic content as well as ROO, O2-, H2O2, OH, and 1O2 radical absorbance capacity. Fruit of Kent cv. strawberry had higher values of phenolic acid, flavonols, anthocyanins, and antioxidant capacities than fruit of Earliglow cv. strawberry under all temperature regimes.

Fruits and leaves from different cultivars of thornless blackberry (Rubus sp.), red raspberry (Rubus idaeus L.), black raspberry (Rubus occidentalis L.), and strawberry (Fragaria ¥ ananassa D.) plants were analyzed for total antioxidant capacity (oxygen radical absorbance capacity, ORAC) and total phenolic content. In addition, fruits were analyzed for total anthocyanin content. Blackberries and strawberries had the highest ORAC values during the green stages, whereas red raspberries had the highest ORAC activity at the ripe stage. Total anthocyanin content increased with maturity for all three species of fruits. Compared with fruits, leaves were found to have higher ORAC values. In fruits, ORAC values ranged from 7.8 to 33.7 mol of Trolox equivalents (TE)/g of fresh berries (35.0-162.1 mol of TE/g of dry matter), whereas in leaves, ORAC values ranged from 69.7 to 182.2 mol of TE/g of fresh leaves (205.0-728.8 mol of TE/g of dry matter). As the leaves become older, the ORAC values and total phenolic contents decreased. The results showed a linear correlation between total phenolic content and ORAC activity for fruits and leaves. For ripe berries, a linear relationship existed between ORAC values and anthocyanin content. Of the ripe fruits tested, on the basis of wet weight of fruit, cv. Jewel black raspberry and blackberries may be the richest source for antioxidants. On the basis of the dry weight of fruit, strawberries had the highest ORAC activity followed by black raspberries (cv. Jewel), blackberries, and red raspberries.

Fruits and leaves from different cultivars of thornless blackberry (Rubus sp.), red raspberry (Rubus idaeus L.), black raspberry (Rubus occidentalis L.), and strawberry (Fragaria ¥ ananassa D.) plants were analyzed for total antioxidant capacity (oxygen radical absorbance capacity, ORAC) and total phenolic content. In addition, fruits were analyzed for total anthocyanin content. Blackberries and strawberries had the highest ORAC values during the green stages, whereas red raspberries had the highest ORAC activity at the ripe stage. Total anthocyanin content increased with maturity for all three species of fruits. Compared with fruits, leaves were found to have higher ORAC values. In fruits, ORAC values ranged from 7.8 to 33.7 mol of Trolox equivalents (TE)/g of fresh berries (35.0-162.1 mol of TE/g of dry matter), whereas in leaves, ORAC values ranged from 69.7 to 182.2 mol of TE/g of fresh leaves (205.0-728.8 mol of TE/g of dry matter). As the leaves become older, the ORAC values and total phenolic contents decreased. The results showed a linear correlation between total phenolic content and ORAC activity for fruits and leaves. For ripe berries, a linear relationship existed between ORAC values and anthocyanin content. Of the ripe fruits tested, on the basis of wet weight of fruit, cv. Jewel black raspberry and blackberries may be the richest source for antioxidants. On the basis of the dry weight of fruit, strawberries had the highest ORAC activity followed by black raspberries (cv. Jewel), blackberries, and red raspberries.

It is often assumed that antioxidant nutrients contribute to the protection afforded by fruits, vegetables, and red wine against diseases of aging. However, the effect of fruit, vegetable and red wine consumption on the overall antioxidant status in human is unclear. In this study we investigated the responses in serum total antioxidant capacity following comsumption of strawberries (240 g), spinach (294 g), red wine (300 ml) or vitamin C (1250 mg) in eight elderly women. Total antioxidant capacity was determined using different methods: oxygen radical absorbance capacity (ORAC) assay, Trolox equivalent antioxidant capacity (TEAC) assay and ferric reducing ability (FRAP) assay. The results showed that the total antioxidant capacity of serum determined as ORAC, TEAC and FRAP, using the area under the curve, increased significantly by 7-25% during the 4-h period following consumption of red wine, strawberries, vitamin C or spinach. The total antioxidant capacity of urine determined as ORAC increased (P < 0.05) by 9.6, 27.5, and 44.9% for strawberries, spinach, and vitamin C, respectively, during the 24-h period following these treatments. The plasma vitamin C level after the strawberry drink, and the serum urate level after the strawberry and spinach treatments, also increased significantly. However, the increased vitamin C and urate levels could not fully account for the increased total antioxidant capacity in serum following the consumption of strawberries, spinach or red wine. We conclude that the consumption of strawberries, spinach or red wine, which are rich in antioxidant phenolic compounds, can increase the serum antioxidant capacity in humans. J. Nutr. 2383-2390, 1998