Chang Yong Lee

Antioxidant capacity of phenolic phytochemicals from various cultivars of plums

Polyphenolic phytochemical extractions of six cultivars of plums (Beltsville Elite B70197, Cacak Best, French Damson, Long John, Stanley, Yugoslavian Elite T101) and Gala apples were performed using 80% aqueous methanol with ultrasound assistance and extracts were analyzed for total phenolics, flavonoids, and antioxidant capacity. The total phenolic contents of various cultivars of plums were in a range of 174 to 375 mg/100 g, expressed as gallic acid equivalents (GAE), on a fresh weight basis. Total flavonoid concentrations ranged from 118 to 237 mg catechin equivalents (CE)/100 g fresh weight. The concentrations of total phenolics and flavonoids in Gala apples were 118±1.4 mg GAE and 62.0±6.9 mg CE per 100 g fresh sample weight, respectively. The stable radical chromogen, ABTS•−, commonly employed for the antioxidant activity measurement, was used to evaluate antioxidant capacity of plums and apples. The total antioxidant capacities, expressed as vitamin C equivalent antioxidant capacity (VCEAC), of fresh plums ranged from 266 to 559 mg/100 g. The order of total antioxidant capacity among different plum cultivars was as follows: Beltsville Elite B70197>Cacak Best⩾French Damson>Yugoslavian Elite T101>Long John>Stanley. The total antioxidant capacity of fresh Gala apple was 205±5.6 mg VCEAC/100 g. There was a good correlation between total phenolics or flavonoids contents and VCEAC at the high level of P<0.001. Dietary polyphenolics from plums may supply substantial antioxidants, which may provide health-promoting advantages to the consumer.

Antioxidant activity of fresh apples.

Vitamin C is used as a dietary supplement because of its antioxidant activity, although a high dose (500 mg) may act as a pro-oxidant in the body. Here we show that 100 g of fresh apples has an antioxidant activity equivalent to 1,500 mg of vitamin C, and that whole-apple extracts inhibit the growth of colon- and liver- cancer cells in vitro in a dose-dependent manner. Our results indicate that natural antioxidants from fresh fruit could be more effective than a dietary supplement.

Nutrition: Antioxidant activity of fresh apples

Vitamin C is used as a dietary supplement because of its antioxidant activity, although a high dose (500 mg) may act as a pro-oxidant in the body. Here we show that 100 g of fresh apples has an antioxidant activity equivalent to 1,500 mg of vitamin C, and that whole-apple extracts inhibit the growth of colon- and liver- cancer cells in vitro in a dose-dependent manner. Our results indicate that natural antioxidants from fresh fruit could be more effective than a dietary supplement.

Comprehensive Study on Vitamin C Equivalent Antioxidant Capacity (VCEAC) of Various Polyphenolics in Scavenging a Free Radical and its Structural Relationship

Antioxidant capacity for a wide range of natural or synthetic polyphenolics was comprehensively evaluated by vitamin C equivalent antioxidant capacity (VCEAC) assay using free blue/green ABTS radicals. The polyphenolics tested are grouped into the following categories: vitamins (β-carotene, α -tocopherol, vitamin A, and vitamin C), phenolic acids (benzoic acid, phenylacetic acid, cinnamic acid, and their derivatives), flavonoids (anthocyanidin, flavanol, chalcone, flavanone, flavone, flavonol, isoflavone, and their derivatives), synthetic food additives (BHA, BHT, TBHQ, and PG), and other miscellaneous polyphenolics (ellagic acid, sesamol, eugenol, thymol, etc.). A positive linear relationship between VCEAC and the number of free OH groups around the flavonoid framework was found, whereas, for phenolic acids, the linear relationship was not as good as with the flavonoid aglycones. Groups of chemicals having comparable structures generally showed similar trends. Polyphenolics commonly showed a higher VCEAC compared to monophenolics. Compounds like gallic acid with 3 vicinal hydroxy substitutions on the aromatic ring in phenolic acids or like epigallocatechin with 3 vicinal hydroxy substitutions on the B ring in flavonoids showed the highest antioxidant capcity among the groups. In the flavonoids, 2 characteristic chemical structures were very important, the catechol moiety in the B ring and the 3-OH functional group in a chroman ring. Glycosylated flavonoids showed less potent antioxidant capacity than their aglycone alone. Synthetic antioxidant food additives (BHA, TBHQ, and BHT) conventionally used in the food industry were less effective antioxidants than ascorbic acid. Other naturally occurring polyphenolics tested followed the expected general trends of phenolic acids and flavonoids.

Optimization of phenolics and dietary fibre extraction from date seeds.

This work was conducted to optimise extraction conditions of phenolics and dietary fibre from date seeds. The effects of solvent to sample ratio, temperature, extraction time, number of extractions and solvent type on phenolic extraction efficiency were studied. At two-stage extraction, each stage 1h duration at 45°C with a solvent to sample ratio of 60:1, is considered optimum. Acetone (50%), and butanone were the most efficient solvents for extraction and purification, increasing the yield and phenolic contents of seed concentrate to 18.10 and 36.26g/100g, respectively. The total dietary fibre of seeds (57.87g/100g) increased after water and acetone extractions to 83.50 and 82.17g/100g, respectively. Nine phenolic acids (free and liberated) were detected in seeds with p-hydroxybenzoic (9.89mg/100g), protocatechuic (8.84mg/100g), and m-coumaric (8.42mg/100g) acids found to be among the highest. After extraction and purification, total phenolic acid content increased significantly from 48.64 to 193.83mg/100g. Protocatechuic, caffeic and ferulic acids were the major phenolic acids found in the concentrates. Based on this study, we believe date seed concentrates could potentially be an inexpensive source of natural dietary fibre and antioxidants and possibly used as a functional food ingredient.

Inhibitory effects of various antibrowning agents on apple slices

A comprehensive study to evaluate the relative antibrowning activity of 36 known compounds was conducted. Five chemical groups, including carboxylic acids, ascorbic acid derivatives, sulfur containing amino acids, phenolic acids and other miscellaneous compounds, were tested on apple slices under the same conditions. Among the compounds tested, oxalic acid, oxalacetic acid, ascorbic acid-2-phosphate, cysteine, glutathione, N-acetylcysteine, kojic acid and 4-hexyl resorcinol belonged to a group that showed the highest inhibitory activity on apple browning. The minimal concentrations of oxalacetic acid, oxalic acid, cysteine and kojic acid, for an effective antibrowning activity, were 0.25, 0.05, 0.05 and 0.05%, respectively. Oxalic acid showed a synergistic effect when 0.02% oxalic acid was used with 1% ascorbic acid or its derivatives.

Nutritional and Functional Properties of Dates: A Review

This review article provides information on the nutritional and functional constituents of dates (Phoenix dactylifera L.) and their seeds from over 80 references. Date flesh is found to be low in fat and protein but rich in sugars, mainly fructose and glucose. It is a high source of energy, as 100 g of flesh can provide an average of 314 kcal. Ten minerals were reported, the major being selenium, copper, potassium, and magnesium. The consumption of 100 g of dates can provide over 15% of the recommended daily allowance from these minerals. Vitamins B-complex and C are the major vitamins in dates. High in dietary fiber (8.0 g/100 g), insoluble dietary fiber was the major fraction of dietary fiber in dates. Dates are a good source of antioxidants, mainly carotenoids and phenolics. Date seeds contain higher protein (5.1 g/100 g) and fat (9.0 g/100 g) as compared to the flesh. It is also high in dietary fiber (73.1 g/100 g), phenolics (3942 mg/100 g) and antioxidants (80400 μ mol/100 g). This detailed information on nutritional and health promoting components of dates and their seeds will enhance our knowledge and appreciation for the use of dates in our daily diet and their seeds as a functional food ingredient.

Growth characteristics of aciduric sporeforming bacilli isolated from fruit juices

Two aciduric, aerobic, sporeforming bacteria were isolated from pasteurized juices. The gram-positive, catalase-positive rods produced spores that were located subterminally in a swollen sporangium. The cultures had an optimal pH of 3.5-4.0 for growth and preferred potato dextrose agar over many of the rich media usually used for cultivating sporeforming bacteria. Spore inocula grew well in apple juice and white grape juice. Red grape juice was inhibitory, perhaps because of the concentrations of certain phenolic compounds. The spores were sufficiently heat resistant (D90 values of 16 to 23 min and z-values of 7.2 to 7.7°C) to survive commercial pasteurization processes.

Antioxidant Activity of Black Tea vs. Green Tea

Dear Editor: A recent article by Leung et al. (1) reported that drinking black tea has benefits equal to those of drinking green tea in terms of their antioxidant capacities because theaflavins present in black tea possess at least the same antioxidant potency as catechins present in green tea. As reported in related studies (2–4), it is clear that a group of theaflavins (TF) in black tea, specifically theaflavin-3,3 -digallate (TF3), has strong antioxidant activity similar to (-)-epigallocatechin gallate (EGCG), a major antioxidant in green tea. However, the concentration of diverse antioxidants in the different teas should be first considered before drawing any conclusions about overall health benefits of teas. We measured the total phenol content and antioxidant capacity of commercial tea products widely available in Europe and the United States. Each bag of green and black tea was extracted with 200 mL distilled deionized water at 100°C for 2 min. The total phenol content was determined by the Folin-Ciocalteau method and total antioxidant capacity was measured in terms of free radical–scavenging activity (5). Black and green teas contained total phenols equal to 124 and 165 mg gallic acid, respectively. We also found that the antioxidant capacity per serving of green tea (436 mg vitamin C equivalents) was much higher than that of black tea (239 mg). Therefore, we conclude that green tea has more health benefits than an equal volume of black tea in terms of antioxidant capacity. This can be explained by the fact that each tea is different in terms of composition and concentration of antioxidant compounds. As reported previously (6–8), TF are low (2–6% of extracted solids) and thearubigens ( 20%) are high in black tea, whereas in green tea, catechins are much higher (30–42%), particularly EGCG, which is the most abundant catechin. In addition, as discussed in our report (9) and another review (7), we must consider the combined effects of the complex bioactive compounds when considering the overall health benefits of a food. In conclusion, the total antioxidant capacity of tea is not related to a particular kind of polyphenol but to the combined activity of diverse antioxidants, including phenolic acids and polyphenols.

Effects of Banana, Orange, and Apple on Oxidative Stress‐Induced Neurotoxicity in PC12 Cells

Banana, orange, and apple are the major fruits in Western and Asian diets. In order to find the effects of these fruits, neuron like PC12 cells were exposed to the extracts of these fruits before H(2)O(2) treatment. We found a significant viability of PC12 cells by the MTT reduction test, which indicated that the phenolics of banana, orange, and apple fruits prevented oxidative stress-induced neurotoxicity. Additional tests by lactate dehydrogenase and trypan blue exclusion assays showed that the extracts reduced oxidative stress-induced neuronal cell membrane damage. These results suggest that fresh apples, banana, and orange in our daily diet along with other fruits may protect neuron cells against oxidative stress-induced neurotoxicity and may play an important role in reducing the risk of neurodegenerative disorders such as Alzheimers disease.