Effects of light exposure on chlorophyll,sugars and vitamin C content of fresh‐cut celery (Apium graveolens var. dulce) petioles

Effects of light exposure (24 μmol m^?2 s^?1) on fresh‐cut celery nutritional quality were evaluated during 8‐day storage at 7 °C using darkness as control. Light exposure preserved 47% chlorophyll a and 48% chlorophyll b contents more than darkness at the end of storage. Sucrose, reducing sugar and glucose contents in light‐stored petioles were 17%, 25% and 67% higher than those in dark‐stored petioles after 8‐day storage, respectively, thus resulting in higher total soluble solids content in light condition. Moreover, l ‐ascorbic acid content increased at 2‐day storage in light condition and was 46% more than in darkness at the end of storage. The fresh weight loss significantly increased in all petioles, and this increase was markedly accelerated by light exposure with a maximum of 1.43% at the end of storage. Dry matter content was induced more by light exposure than by darkness at 2‐day storage.     

Influence of whole and fresh-cut mango intake on plasma lipids and antioxidant capacity of healthy adults

The content of antioxidant compounds and antioxidant capacity of whole and fresh-cut mango, stored for 10 days at 12 °C and 5 °C, respectively and their influence on serum antioxidant capacity and lipid profile of normolipidemic humans were studied. Whole mango (WM) had a higher content of flavonoids, ??-carotene and antioxidant capacity, determined by oxygen radical scavenging capacity, (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, than the fresh-cut fruit (FCM). FCM presented higher amounts of total phenols. Thirty normolipidemic volunteers, ages 20-50 years, were randomly divided into two groups (WM and FCM) 15 persons each. During 30 consecutive days volunteers from groups 1 and 2, received daily 200 g of WM or FCM, respectively. Lipid levels and antioxidant capacity in plasma were determined at 0, 15 and 30 days of the experiment. Serum triglycerides were significantly reduced after 30 days of supplementation with WM and FCM (37 and 38% respectively); VLDL levels were reduced in a similar proportion. No significant changes in other plasma lipid levels were observed. Both treatments increased plasma antioxidant capacity measured by ORAC and TEAC methods. According to the results obtained in this study, we suggest that addition of mango fruit to generally accepted healthy diets could have a beneficial effect preventing hypertryglyceridemia, and that fresh-cut processing does not affect the beneficial properties of mango.     

Development and validation of a novel real-time PCR method for the detection of celery (Apium graveolens) in food

The paper presents a novel real-time PCR method allowing the detection of traces of celery (Apium graveolens) in complex food matrices. The method is based on the amplification of a sequence of the gene coding for the Apium graveolens NADPH-dependent mannose-6-phosphate reductase. It allows the detection of three commonly used celery varieties, celery roots (Apium graveolens var. rapaceum), celery stalks (Apium graveolens var. dulce) and leaf celery (Apium graveolens var. secalinum) and does not show any cross-reactivity with 64 biological species, including ten members of the Apiaceae family. The limit of detection, determined by analysing serially diluted celery extracts, is 10 pg celery DNA for all three celery varieties. In spiked model sausages, the LOD is 0.005% celery. The real-time PCR method was applied to 26 commercial food products. Celery DNA was found in one out of ten samples without any information about the presence of celery.     

Changes in vitamin C content and antioxidant capacity of raw and germinated cowpea (Vigna sinensis var. carilla) seeds induced by high pressure treatment

The effect of high pressure treatment on the vitamin C content and antioxidant capacity of raw and germinated cowpea seeds (Vigna sinensis var. carilla) at 300, 400 and 500 MPa for 15 min at room temperature has been investigated. A considerable amount of vitamin C was detected in germinated cowpeas, but the vitamin was not detected in raw seeds. An increase on the antioxidant capacity (TEAC) in cowpea sprouts was also observed (58–67%). High pressure treatment (HP) slightly modified vitamin C content and TEAC and, after pressurization at 500 MPa, the decrease was more pronounced, although the germinated seeds submitted to this HP treatment still provided a high amount of vitamin C (15–17 mg/100 g d.m.) and the antioxidant capacity was 26–59% higher than that of the raw cowpeas. The HP process can provide minimally processed fresh-like sprouts of high quality.     

Light exposure during storage preserving soluble sugar and l-ascorbic acid content of minimally processed romaine lettuce (Lactuca sativa L.var. longifolia)

Minimally processed romaine lettuce (MPRL) leaves were stored in light condition (2500 lux) or darkness at 4 °C for 7 d. Light exposure significantly delayed the degradation of chlorophyll and decrease of glucose, reducing sugar, and sucrose content, and thus preserved more total soluble solid (TSS) content at the end of storage in comparison with darkness. While, it did not influenced starch content that progressively decreased over time. The l-ascorbic acid (AA) accumulated in light-stored leaves, but deteriorated in dark-stored leaves during storage. The dehydroascorbic acid (DHA) increased in all leaves stored in both light and dark condition, of which light condition resulted in less DHA than darkness. In addition, the fresh weight loss and dry matter significantly increased and these increases were accelerated by light exposure. Conclusively, light exposure in applied intensity effectively alleviated MPRL quality deterioration by delaying the decreases of pigments, soluble sugar, TSS content and accumulating AA.     

Total phenolics,antioxidant properties and quality of fresh-cut onions (Allium cepa L.) treated with mild-heat

This study investigated the effect of mild-heat on fresh-cut onion slices by treating in hot water (50, 60, 70 °C) for 1 min. Total phenolics (TP), antioxidant properties, colour, and weight loss of slices were evaluated during 4 °C storage at 7-day intervals (21 days total). The 60 °C heat treatment resulted in a significant increase in TP, from 44.92 to 52.32 mg GAE/100 g. Except for 50 and 70 °C treatments, TP in control and 60 °C treated fresh-cut onions decreased during storage. The antioxidant properties of fresh-cut onions were 1.31, 0.99, and 62.49 μM TE/g using ABTS, DPPH, and ORAC assays, respectively. The mild-heat treatments did not affect ABTS and DPPH antioxidant activities and the colour of fresh-cut onions. The storage time had mixed effect on the antioxidant properties (ABTS decreased; DPPH and ORAC remained fairly stable). The 50 °C samples exhibited the lowest weight loss during 21-day storage.     

Inhibitory effect of onion extract on polyphenol oxidase and enzymatic browning of taro (Colocasia antiquorum var. esculenta)

The inhibitory effect of onion extract on polyphenol oxidase and enzymatic browning of taro was investigated. The polyphenol oxidase from taro was strongly inhibited by various reducing agents, such as l-ascorbic acid, l-cysteine, dithiothreitol, glutathione and sodium pyrosulfite. The enzyme was also inhibited by addition of onion extract. Regardless of substrates used, the addition of heated onion extract at 100 °C for 10 min, gave a stronger inhibitory effect on taro polyphenol oxidase activity than did fresh unheated extrtact. The inhibitory effect of onion extract was dependent on heating temperature and time. The addition of glucose, glycine, or both to the onion extract, during heating, stimulated the inhibitory effect of the onion extract, suggesting that non-enzymatic browning products, produced during heating, might be responsible for the stronger inhibitory action of the heated onion extract.     

Chemical characterization and antioxidant capacity of berries from Clidemia rubra (Aubl.) Mart. (Melastomataceae)

The flora of Latin America attracts gaining interest as it provides a plethora of still unexplored or under-utilized fruits that can contribute to human well-being due to their nutritional value and their content of bioactive compounds. Clidemia rubra (Aubl.) Mart. is a shrub belonging to the family of the Melastomataceae that grows preferably in a tropical climate. This paper comprises a nutritional characterization of the berries from Clidemia rubra and provides data on the phenolic compounds as well as the antioxidant capacity of the fruit. Findings in macronutrients like protein, carbohydrates, and fat were comparable to that of common berry fruits. Clidemia rubra berries seemed to be a good source for dietary fibers and some minerals (Ca, Mn, and Zn). In contrast, contents of titratable acids and ascorbic acid were low. The polyphenolic profile was determined by using HPLC-MS/MS in comparison to standard compounds. Noteworthy amounts of cyanidin 3-O-rutinoside (39.43 ± 1.66 mg/100 g fresh weight (FW)), delphinidin 3-O-rutinoside (23.74 ± 1.18 mg/100 g FW), cyanidin 3-O-glucoside (11.68 ± 0.56 mg/100 g FW), and delphinidin 3-O-glucoside (6.08 ± 0.35 mg/100 g FW) were found. Non-anthocyanin phenolic constituents were phenolic acids (gallic, protocatechuic, p-hydroxy-benzoic, vanillic, and caffeic acid), flavan-3-ols (epigallocatechin, epigallocatechin gallate, and epicatechin gallate), and 11 different myricetin and quercetin derivatives of which quercetin 3-O-arabinoside (5.26 ± 0.16 mg/100 g FW) and quercetin 3-O-rhamnoside (5.06 ± 0.08 mg/100 g FW) were dominating. Anthocyanins and ascorbic acid were mainly responsible for the antioxidant capacity of Clidemia rubra berries assessed with the total oxidant scavenging capacity (TOSC) assay.     

Effect of hydrothermal treatment on the antioxidant properties of broccoli (Brassica oleracea var. botrytis italica) florets

In the extracts of fresh raw and frozen broccoli, caffeic, ferulic, sinapinic acids and kaempferol were identified. Boiling reduced the amounts of caffeic acid and kaempferol in both samples. The concentration of polyphenols was 2.69 mg/g fresh mass and 0.96 mg/fresh mass in fresh raw broccoli and frozen raw broccoli, respectively. Boiling significantly decreased the amounts of phenolic compounds in fresh broccoli (1.58 mg/g of fresh mass). In the case of frozen broccoli, boiling increased the concentration of polyphenols by 38%. Fresh broccoli extract neutralized free radicals by 19.87%. Boiling significantly reduced its antiradical activity (to 15.06%). Samples of frozen broccoli had a 27.06% antiradical ability. Boiling did not change the antiradical activity in frozen broccoli case. Hydrothermal processing significantly influenced on the ability of the extracts to inhibit the decolorization of β-carotene emulsion. The extract of fresh broccoli had a higher activity when uncooked. Boiling seemed to increase this activity in the case of frozen broccoli samples. The results of the studies on the ability of broccoli extracts to inhibit linoleic acid autooxidation were ambiguous and depended on the method applied. No correlation was found between the content of phenolic compounds and the antioxidant activity of the extracts, regardless of the experimental variant and technique used.     

Kinetic study of the antioxidant compounds and antioxidant capacity during germination of Vigna radiata cv. emmerald, Glycinemax cv. jutro and Glycine max cv. merit

The purpose of this study was to determine the antioxidant capacity and the content of antioxidant compounds in raw mung bean seeds and sprouts (Vigna radiata cv. emmerald) germinated for 2, 3, 4, 5 and 7 days and of soybean seeds of Glycine max cv. jutro germinated for 2, 3 and 4 days and of Glycine max cv. merit germinated for 2, 3, 4, 5 and 6 days. Antioxidant compounds, such as vitamin C and E, total phenolic compounds and reduced glutathione (GSH) were studied. Antioxidant capacity was measured by superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), trolox equivalent antioxidant capacity (TEAC) and inhibition of lipid peroxidation in unilamellar liposomes of egg yolk phosphatidylcholine (PC). The results indicated that changes in the contents of vitamin C, vitamin E and GSH depended on the type of legume and germination conditions. Sprouts of mung bean and soybeans provided more total phenolic compounds than did raw seeds. The SOD-like activity increased after germination of mung bean seeds for 7 days, by 308%, while no change was observed in sprouts of Glycine max cv. jutro and an increase was observed after 5 and 6 days of germination (∼20%) in Glycine max cv. merit. PRTC and TEAC increased during the germination process and retentions of 28–70% and 11–14%, respectively, for soybean, and 248% and 61%, respectively, for mung bean were observed at the end of germination. The inhibition of lipid peroxidation increased by 389% in 5–7 days’ germination of Vigna radiata cv. emmerald sprouts, and 66% in Glycine max cv. merit sprouts whilst, in Glycine max cv. jutro, germination did not cause changes in lipid peroxidation inhibition. According to the results obtained in this study, germination of mung bean and soybean seeds is a good process for obtaining functional flours with greater antioxidant capacity and more antioxidant compounds than the raw legumes.     

Determination of lutein and zeaxanthin and antioxidant capacity of supercritical carbon dioxide extract from daylily (Hemerocallis disticha)

Lutein and zeaxanthin were extracted from daylily (Hemerocallis disticha) flowers using supercritical fluid extraction-carbon dioxide (SFE-CO₂) at a temperature range of 50–95 °C and pressure range of 300–600 bar. The extracts were analysed by HPLC with a C30 column and an isocratic solvent system: methanol/methyl-tert-butyl ether = 86/14 (v/v). Moreover, the antioxidant capacities of the extracts were evaluated by a 2,2-diphenyl-2-picrylhydrazyl radical scavenging assay and a chemiluminescence assay to measure the scavenging activity of hydrogen peroxide, superoxide anion and hydroxyl radical. The optimal lutein and zeaxanthin extraction could be achieved at 80 °C and 600 bar, and the extraction pressure was the most important parameter for SFE-CO₂. In addition, the extracts had significantly higher antioxidant activities in all antioxidant assays.     

Variation in antioxidant enzyme activities and nonenzyme components among cultivars of rabbiteye blueberries (Vaccinium ashei Reade) and V. ashei derivatives

Fruit from 42 blueberry (Vaccinium species) cultivars, including 36 rabbiteye cultivars (Vaccinium ashei Reade), 3 V. ashei hybrid derivatives and 3 northern highbush (V. corymbosum L.) standards, were evaluated for antioxidant activities (AA), levels of antioxidant enzymes [catalase (CAT), ascorbate peroxidase (AsA-POD), glutathione reductase (GR), glutathione peroxidase (GSH-POD), superoxide dismutase (SOD), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDAR) and guaiacol peroxidase (G-POD)], and antioxidant nonenzyme components [ascorbic acid (ASA) and glutathione (GSH)]. The results of this study showed that cultivars had varying levels of AA, a wide range of antioxidant enzyme activities and various amounts of nonenzyme components. The correlations between AA and all of the enzyme activities or nonenzyme components were positive and high in the 42 cultivars tested in this study. The correlation (R²) values between AA and CAT, SOD, DHAR, MDAR, GSH-POD, GR, G-POD and AsA-POD were 0.91, 0.91, 0.91, 0.91, 0.90, 0.90, 0.90, and 0.90, respectively. The correlations between AA and ASA and GSH were 0.94 and 0.92, respectively. Among all 42 cultivars, ‘Early May’ had the highest activities of the AA, AsA-POD, G-POD, DHAR and MDAR and the highest amounts of ASA and GSH, whereas ‘Elliott’ had the highest levels of GR, GSH and SOD.     

Polyphenols and antioxidant capacity of Phaseolus vulgaris stored under extreme conditions and processed

Phaseolus vulgaris is a foodstuff that not only supplies nutrients, but also bioactive compounds with antioxidant capacity; however, bad post-harvest storage or processing can diminish the antioxidant capacity. In this work, the effect of storage under extreme conditions, of thermal processing and of fermentation on the content of phenolic compounds and their antioxidant capacity (AA) in beans of just harvested P. vulgaris were evaluated. Combination of temperatures of 30 and 50 °C and relative humidity of 11% and 80% for 150 days were evaluated. Extreme storage conditions drastically decreased the AA, demonstrating that post-harvest storage at low temperature and humidity preserves the antioxidant capacity of the beans. Regarding processing, cooking decreased the scavenging effect and the AA by 63.5% and 56.8%, while fermentation decreased them by only 14% and 22%, respectively. It was concluded that the loss of antioxidant capacity due to heating is less in fermented beans.     

Comparative antioxidant, antiproliferative and phase II enzyme inducing potential of sorghum (Sorghum bicolor) varieties

Epidemiological evidence has linked consumption of sorghum with reduced incidences of gastrointestinal cancer, especially cancer of esophagus. No information is available on how sorghum may effect the chemoprotective properties. We investigated in vitro potential of eight sorghum varieties to induce phase II detoxifying enzymes using the NAD(P)H:quinone oxidoreductase (NQO) enzyme assay, and also inhibit proliferation of esophageal, OE33, and colon, HT-29, carcinoma cells using the PicoGreen and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays; these properties were compared to phenolic profile and antioxidant activity of the sorghum. Black sorghum extract high in 3-deoxyanthocyanins was the most potent NQO inducer, doubling NQO activity at 5.0 μg/mL and maximally inducing the enzyme activity by 3.0 times. White sorghum was a moderately strong inducer, maximally increasing NQO activity by 80%; tannin-containing sorghums were non-inducers. On the other hand, the tannin-containing sorghum extracts had strongest antiproliferative activity against both OE33 and HT-29 cells (IC₅₀, 38-105 μg/mL); the white sorghum extract was the least potent (IC₅₀, 389->800 μg/mL). Antiproliferative activity correlated with antioxidant activity whereas NQO-inducer capacity did not. Sorghum extracts have strong chemoprotective potential which is partially independent of their antioxidant properties. They may thus be valuable health-promoting ingredients in whole-grain based products.     

Influence of combined hot air and UV-C treatment on the antioxidant system of minimally processed broccoli (Brassica oleracea L. var. Italica)

Broccoli develops a fast senescence that deteriorates the nutritional quality of the product. In this work, a combined treatment with hot air and UV-C were applied to minimally processed broccoli florets to investigate their effects on the antioxidant system during storage at 20 °C. Application of UV-C and heat enhanced by approximately 13% the levels of total antioxidants immediately after treatment. These levels were lower than initials in both control and treated samples. Nevertheless, higher values (ranged from 12 to 50%) were also detected in treated samples during storage. In general, higher values of antioxidants were correlated with elevated levels of phenols (from 10 to 17%) and ascorbic acid (from 11 to 17%) in treated florets. The increment in the content of phenolics in treated broccolis was correlated to an increased phenylalanine ammonia lyase (PAL) activity. The combined treatment also affects the activity of enzymes involved in removal of reactive oxygen species. An increase of about 50% in superoxide dismutase activity was detected after treatment. During the first days of storage this higher activity was about 40%. Enzymes that remove H₂O₂ like catalase and ascorbate peroxidase showed an enhanced activity toward the end of storage. The combined treatment diminished the peroxidase (POX) activity approximately 60% after the treatment and near 50% after two days of storage, suggesting a minor role of this enzyme in detoxification of H₂O₂. In conclusion, combined treatment may contribute to enhance the protection against oxidative molecules not only by increasing levels of phenolics and ascorbic acid but also by enhancing the activity of enzymes involved in removing reactive oxygen species.