Loss Of Antioxidant Capacity Research Articles

Influence of Pasteurisation (Conventional vs. Radiofrequency) and Chill Storage on Retention of Ascorbic Acid, Tocopherol and Carotenoids in Salmorejo.

Salmorejo, a Mediterranean tomato-oil puree, is considered a dietary source of antioxidant vitamins C and E and carotenoids lycopene and β-carotene, the latter endowed with provitamin A activity. However, these antioxidants can be degraded in oxidation reactions catalysed or not by enzymes during pasteurisation and storage treatments used to stabilise the salmorejo before consumption. Due to its better penetration, the use of dielectric heating by radiofrequency (RF) may improve results of pasteurisation in this product. The objective was to assess the effects of pasteurisation temperature (70-100 °C, at 5 °C intervals) and storage time (0-5 months, at one-month intervals) on levels of ascorbic acid, α-tocopherol and carotenoids and antioxidant capacity (AC) in salmorejo pasteurised (over 10 s) by conventional (CH) or RF continuous heating. Two successive experiments were conducted to select an adequate pasteurisation temperature for use in the shelf-life study. Pasteurisation upon tested conditions allows a good retention of salmorejo antioxidants. Either CH or RF pasteurisers can be used with similar results. Vitamin C (L-ascorbic + dehydroascorbic acids) was more abundant (15-19 mg 100 g-1) than carotenoids (0.9-2.6 mg 100 g-1) (all-trans + cis lycopene and β-carotene) and α-tocopherol (0.8-1.2 mg 100 g-1) in the pasteurised product. Using excessively low temperatures (70 °C) resulted in partial losses of the three antioxidants, possibly due to oxidase residual activities. Intensifying thermal treatment improved this issue with minor losses of the thermolabile vitamin C and increased carotenoid content. Using a suitable temperature (80 °C) did not prevent most vitamin C from being degraded by the first month, while α-tocopherol, and, to a lesser extent, carotenoids, showed good retention levels during shelf life under refrigeration. Vitamins C and E and carotenoids, either by degradation, regeneration or releasing, likely contribute to the AC in salmorejo. Phenolic antioxidant response, radical-scavenging activities and redox potential values confirmed this finding. The pasteurised-chilled salmorejo shows good antioxidant properties with potential health implications, a positive nutritional aspect for consumers of this tomato-oil homogenate. The losses of antioxidants and AC due to pasteurization would be of little relevance compared to the losses accumulated during shelf life.

Capacidade antioxidante equivalente ao trolox em sementes de Coffea arabica L.

ABSTRACT The causes of the low desiccation tolerance and low longevity of coffee seeds have not yet been fully elucidated, and a full understanding of their complex physiology is of great interest. Among several alternatives, the loss of antioxidant capacity in seeds may be related to their rapid loss in quality during storage. The objective of this study was to determine the total antioxidant capacity of coffee harvested at different ripeness stages before and after the storage of seeds with different water contents and to relate antioxidant capacity to physiological quality. Seeds in the greenish-yellow or cherry stages, recently harvested or stored for nine months at 10 °C with 40, 30, 20 and 12% water content (wet basis - wb), were submitted to physiological and biochemical quality evaluations, and the Trolox equivalent antioxidant capacity (TEAC) was determined. The germination and root protrusion of coffee seeds from greenish-yellow and cherry fruits were not affected by drying, but seeds harvested at physiological maturity had greater vigor when the moisture content was lower. The quality of coffee seeds decreased during storage, and this decrease was greater in seeds stored with higher water contents. Coffee seeds in the greenish-yellow stage had a higher antioxidant capacity than those in the cherry stage when recently harvested, but there was a substantial reduction in this capacity during storage at both maturation stages. Coffee seed deterioration is related to a reduction in antioxidant capacity, and the isoenzymatic profiles of the antioxidant process are little affected by the seed maturation stage. The deterioration of coffee seeds during storage is related to a reduction in their total antioxidant capacity, regardless of their maturation stage, being more pronounced in the greenish-yellow stage.

Impact of air temperature on drying characteristics and some bioactive properties of kiwi fruit slices

Drying kinetics, ascorbic acid content (AAC), total phenolic content (TPC), and antioxidant capacity (AC) of kiwifruits at different temperatures (60 ?C, 70 ?C, and 80) were investigated. The drying rate and effective moisture diffusivity of kiwifruits were the highest at 80 ?C. Additionally, the Parabolic model best predicts the experimental moisture ratio at 60 ?C and 70 ?C, while the Page model described the drying curve at 80 ?C. On the other hand, the AAC, TPC, and AC of kiwifruits were significantly influenced by temperature. Degradation of AAC increased with the increment in temperature, while TPC and AC were higher at the higher temperature. The range of the AAC, TPC, and AC of fresh and dried fruits were 165.59?12.58-462.81?11.53 mg/100 g DW, 747.66?16.09-1846.87?15.52 mg/100 g GAE DW, and 0.283?0.15-1.903?0.15 mmol TE/100 g DW, respectively. The highest AAC, TPC, and AC losses were calculated as 64.22%, 59.43%, and 85.13%, respectively.

Exogenous Salicylic and Ascorbic Acids Delay Peel Enzymatic Browning and Improve Quality of Dried Figs Under Low-Temperature Storage

Dried figs undergo undesirable changes during storage, particularly browning reactions. An approach to this issue is using, separately, antioxidants such as ascorbic acid and salicylic acid as anti-enzymatic browning agents. The aforementioned chemical agents were tested at the concentrations 0.1, 0.2, and 0.3% during 6 weeks-storage at 4 °C, for dried figs sealed within polyethylene terephthalate bags. For both agents, the results demonstrated that a concentration of 0.3% lowered the browning index compared to the control by 55 and 54%, respectively. Compared to other concentrations, the same concentration suppressed polyphenol oxidase to 75 and 80%, respectively. A significant impact (p < 0.05), for both treatments, particularly at 0.3%, was obtained on dried figs quality by lowering the total phenols loss and antioxidant capacity loss during the storage period. The results of vibrational spectroscopy were able to confirm the same pattern of the polyphenols compared to those examined by UV-Visible spectrophotometry, revealing thus a decreasing absorbance. A similar tendency was revealed using integrated intensity around the phenols vibration within the region of 1175–940 cm-1, as the concentrations of anti-browning agents increased. Thus, pre-storage ascorbic and salicylic acids treatments at 0.3% on dried figs could be appropriate to delay enzymatic browning and quality loss and, therefore to extend their shelf-life.

Effect of bovine serum albumin on the stability and antioxidant activity of blueberry anthocyanins during processing and in vitro simulated digestion

The application of blueberry anthocyanins (ANs) was limited due to their low in-process stability and bioavailability. In our study, the stability and antioxidant capacity of ANs before and after adding bovine serum albumin (BSA) were examined by simulating various processing, storage (light, sucrose, and vitamin C (Vc)), and in vitro simulated digestion parameters. For this purpose, pH-differential method, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), peroxyl scavenging capacity assay, and cellular antioxidant assay were conducted. BSA at different concentrations, specifically at 0.15 mg/mL, inhibited the degradation of ANs and the loss of antioxidant capacity. The results suggest that BSA has a positive effect on ANs.

Effects of pre-storage ascorbic and salicylic acids treatments on the enzymatic browning and nutritional quality of dried fig: Combined use of biochemical and ATR-FTIR analyses

The effect of ascorbic acid (AA) and salicylic acid (SA) used separately at the following concentrations 0.1, 0.2 and 0.3 %, on enzymatic browning and quality of “Nabout’’ dried fig during 6 weeks-storage at 4 °C within sealed polyethylene terephthalate (PET) bags, was investigated. The results showed that AA and SA at higher concentrations, particularly at 0.3 %, lowered the browning index compared to the control by 55 and 54 % respectively. The same dose suppressed samples polyphenoloxidase (PPO) to 75 and 80 %, respectively, compared to other concentrations. Both treatments showed a significant impact (p < 0.05) on dried figs quality by lowering the total phenols and antioxidant capacity loss during storage period. This trend was significantly important when the concentration applied was maximum (0.3 %). The same pattern was observed using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) technique, that showed a decreasing absorbance and integrated intensity around the vibration region of 1175−940 cm−1. This tendency was also depressed with the increase of anti-browning agents’ concentration. High concentrations of AA (0.3 %) and SA (0.3 %), separately, minimized the overlapping in this region, showing high integrated intensities compared to other concentrations. In conclusion, the pre-storage application either of AA or SA at 0.3 % on dried figs could be appropriate to delay enzymatic browning and quality loss and therefore to extend their shelf-life.

Energetic, antioxidant, inflammatory and cell death responses in the red muscle of thermally stressed Sparus aurata.

For a comprehensive understanding of fish responses to increasing thermal stress in marine environments, we investigated tissue energetics, antioxidant levels, inflammatory and cell death responses in Sparus aurata (gilthead seabream) red muscle during exposure to elevated temperatures (24°C, 26°C, 30°C) compared to the control temperature of 18°C. Energetic aspects were assessed by determining lactate, glucose and lipids levels in blood plasma, ATP, ADP and AMP levels, and AMPK phosphorylation as an indicator of regulatory changes in energy metabolism, in tissue extracts. Oxidative defence was assessed by determining superoxide dismutase, catalase and glutathione reductase maximum activities. Moreover, xanthine levels were determined as an indicator of purine conversion to xanthine and associated ROS production. In the context of inflammatory response and cell death due to oxidative stress, pro-inflammatory cytokines (IkBα phosphorylation, IL-6 and TNFα) levels, and LC3 II/I ratio and SQSTM1/p62 as indicators of autophagic-lysosomal pathway were also determined. A recovery in the efficacy of ATP production after a marked decrease during the 1st day of exposure to 24°C is observed. This biphasic pattern is paralleled by antioxidant enzymes' activities and inflammatory and autophagy responses, indicating a close correlation between ATP turnover and stress responses, which may benefit tissue function and survival. However, exposure beyond 24°C caused tissue's antioxidant capacity loss, triggering the inflammatory and cell death response, leading to increased fish mortality. The results of the present study set the thermal limits of the gilthead seabream at 22-24°C and establish the used cellular and metabolic indicators as tools for the definition of the extreme thermal limits in marine organisms.

Pulpa de camu camu (Myrciaria dubia (H.B.K.) Mc Vaugh) en tres estados de madurez: efecto de la concentración al vacío, congelamiento y del tratamiento con ultrasonido en sus propiedades funcionales

El camu-camu (Myrciaria dubia (H.B.K.) Mc Vaugh) es ampliamente cultivado en la región amazónica peruana. El objetivo de este trabajo fue estudiar la pulpa de la fruta en tres estados de madurez, sometidos a ultrasonido, concentración al vacío, empacados al vacío, congelado a -20ºC, y estudiar los efectos sobre sus componentes bioactivos, los mohos y levaduras. La pulpa de camu camu, que presentó el mayor contenido de componentes bioactivos (estado maduro) fue sometida al tratamiento ultrasónico a 40 KHz con tiempo 0, 1, 3, 5, 7 y 10 minutos. Los valores fueron de ácido ascórbico (2151 ± 16 mg x 100 g-1), polifenoles totales (739 ± 24 mg x 100 g-1) y capacidad antioxidante como ABTS (IC50 = 2.94 ± 0.11 μg x mL-1) y DPPH (IC50 = 7.43 ± 0.12 μg x mL-1). El método de concentración al vacío y congelado a -20ºC durante 90 días incrementó el nivel de ácido ascórbico en 207,17 % debido a su concentración de 50%, llegando a una pérdida total de polifenoles en el tercer mes de almacenamiento de tan sólo 6,6 % de su contenido inicial tiempo cero. Se escogió el tratamiento donde se trató la pulpa fresca con ultrasonido durante 5 minutos, para su almacenamiento por 120 días a -20ºC y se observó un aumento de su capacidad antioxidante en 20,5% para polifenoles totales, 2% para ABTS y 23% para DPPH con respecto a la pulpa no tratada. Concluimos que el tratamiento con ultrasonido, la concentración al vacío y el congelamiento, aumentan el tiempo de conservación, poca perdida de su capacidad antioxidante aumenta su capacidad reductora.

Effect of vacuum freeze-drying on the antioxidant properties of eggplants (Solanum melongena L.)

The Vacuum Freeze Drying (VFD) process is a low temperature drying technique that can be used for food preservation. The aim of this work is to evaluate how VFD operating conditions affect the amount of some nutritional compounds of eggplants (Solanum melongena L.). The product samples were freeze-dried under different pressure and temperature conditions and had their ascorbic acid (AA) concentration, total polyphenol content (TPC) and antioxidant capacity (AC) measured before and after processing. Temperature was found to have a significative effect on primary drying times: considering results obtained at 40 Pa, the duration moved from 8.6 ± 2.5 h when the process was carried out at 0 °C, to 20.9 ± 7.8 h at −30 °C. Chamber pressure had a less significant effect, being drying time, at 0 °C, ranging from 6.2 ± 2.3 h, for the test at 20 Pa, to 8.6 ± 2.5 h, for test done at 40 Pa. Very low temperatures resulted in higher AC retentions, being the AC loss 68.6 ± 1.5% at 0 °C and 49.9 ± 3.2% at −30 °C (at 10 Pa), while having a negative impact on the AA content, being the AA loss 12.2 ± 1.7% at 0 °C and 37.9 ± 3.4% at −30 °C (at 10 Pa). Higher pressures were favorable for TPC retention in the dried product: being the TPC loss 47.7 ± 5.5% at 10 Pa and 32.5 ± 8.5% at 40 Pa (at 0 °C). A similar trend can be observed for AC, where the AC loss was 68.8 ± 1.5% at 10 Pa and 35.7 ± 12.1% at 40 Pa (at 0 °C). Freezing stage had a non-significant effect on the targeted compounds.

Ready-to-eat cherry tomatoes: Passive modified atmosphere packaging conditions for shelf life extension

Abstract This work evaluated the application of passive modified atmosphere packaging (MAP) technology for shelf life extension of ready-to-eat cherry tomatoes (cv. Tiny Bell), assessing the influence of perforated and non-perforated packaging films on product’s physicochemical, sensory and nutritional quality. Cherry tomatoes were washed, sanitized and packaged in continuous (PE) and perforated (pPE) polyethylene and perforated polypropylene (pPP). Packaged tomatoes and unpackaged tomatoes as control were stored at 7 °C for 21 d. MAP technology proved to be beneficial for cherry tomato postharvest preservation, showing reduced weight loss and sensory deterioration with respect to control. Moderate atmospheric modification achieved with the films studied (14–19 kPa for O2 and 2–3 kPa for CO2) showed a significant effect in climacteric peak magnitude. Color and firmness retention were observed for tomatoes in MAP conditions: hue angle was reduced by 5% in MAP in contrast to 18% in control, while firmness remained constant in MAP and showed a loss of 37% for control tomatoes. Lowest O2 concentrations achieved using PE packages (14.2 kPa) resulted in the highest firmness retention and greater reduction of respiration rate. MAP did not have an effect on nutritional quality, showing 11% loss of antioxidant capacity and 40% lycopene loss, as observed for control tomatoes. Considering sensory quality, ready-to-eat cherry tomatoes packaged in PE exhibited a shelf life of at least 21 d at 7 °C. This is the packaging condition recommended for cherry tomato (cv. Tiny Bell) postharvest refrigerated storage in the present study.

Combined Effect of UV-C Light and Mild Heat on Microbial Quality and Antioxidant Capacity of Grapefruit Juice by Flow Continuous Reactor

The efficacy of combined UV-C radiation (39.6 J/L) and mild heat (65.0 ± 3.0 °C) on the inactivation of aerobic mesophilic and yeast/molds in grapefruit juice (GFJ) (pH 3.12, °Brix 9.6, 2500 NTU, absorption coefficient 42.9 cm−1) using a flow continuous reactor was investigated. Changes in microbial load, ascorbic acid, and total phenols content, antioxidant capacity, pH, acidity, °Brix, and color were evaluated during 28 days at 4.0 ± 1.0 °C. The spoilage microorganisms were inactivated due to the synergistic effect of both technologies, but the ascorbic acid (74%) and phenol (14%) contents were considerably reduced, with losses of antioxidant capacity (DPPH• = 19% and ABTS•+ = 16%). During storage, the ascorbic acid level and antioxidant capacity gradually decreased. On the other hand, the treated GFJ did not show microbial growth while the untreated GFJ reached more than 4 logs CFU/mL. Conversely, no changes (P < 0.05) in the physicochemical parameters were observed. Principal component analysis is discriminated among the antioxidant compounds and physicochemical properties of the untreated and treated GFJ during storage. Application of UV-C in a Teflon-coil reactor combined with mild heat resulted in longer microbial shelf stability in the GFJ and was able to maintain the physicochemical properties of the juice unchanged during 28 days of storage. Hence, this process can be effectively applied as a combined method to ensure microbial quality.

INFLUENCES OF MALTODEXTRIN AND HOT AIR TEMPERATURE ON LOSSES OF BETACYANIN AND ANTIOXIDANT CAPACITY IN BEETROOT JUICE SPRAY DRYING

Beetroot (Beta vulgaris L.), which is rich in betacyanin and antioxidant compounds, has been utilized as a good source of red pigment and antioxidants. Nevertheless, these compounds are thermally sensitive, consequently, being degraded in processes conducted at high temperature. This research focused on effects of maltodextrin and hot air temperature on losses of betacyanin and antioxidant capacity in spray drying of beetroot juice. Results indicated that adding maltodextrin and temperature of hot air significantly influenced on loss by thermal effect, consequently, on the recovery yield of betacyanin and antioxidant capacity of beetroot juice powder. Adding maltodextrin enhanced protection of betacyanin and antioxidants in beetroot juice against thermal effect. Increasing temperature of hot air caused increase in loss by thermal effect of betacyanin and antioxidant capacity. The loss of antioxidant capacity by thermal effect was higher than that of betacyanin. Results also indicated that the suitable conditions of spray drying of beetroot juice are adding maltodextrin to reach 30 % w/w of total solid content and 150 oC of hot air temperature.

Antioxidant Capacity Analysis of Blackberry Extracts with Different Phytochemical Compositions and Optimization of their Ultrasound Assisted Extraction.

High antioxidant capacity molecules, such as anthocyanins, occur naturally in blackberry (Rubus fruticosus). In particular, 'Dasha' blackberry cultivar has scarcely been studied and, it is becoming economically more important in Mexico. In this study, several blackberry extraction conditions, conferred different amounts of detectable phytochemical groups that in turn were analysed with a new approach to investigate their influence on antioxidant capacity (AC). Additionally, a central composite design (CCD) was proposed to study effects of temperature and acidification on AC. Finally, an original approach was used to disclose interactions between the phytochemical content and the AC. Changes in size of the particles during extraction were reported for the first time, and the results showed evidence of swelling and dissolving of particles. UAE of fine and thick powders achieved similar efficiencies in contrast with maceration which showed large differences for the extraction of the tested sizes. CCD showed that low levels of acidification and high levels of temperature resulted in higher extraction of phytochemicals and AC. HPLC show that the main anthocyanidin may represent 88% of the total anthocyanins. Due to its relatively high abundance, cyanidyn-3-glucoside showed evidence of being the main cause of the changes in AC in 'Dasha' extracts. The use of mild conditions resulted in no degradation of anthocyanins and, therefore, there are no AC losses. A correlation plane was proposed to study synergisms of the extracts with other anthocyanins or phenolics.

The effect of thermal treatment on antioxidant capacity and pigment contents in separated betalain fractions.

Increased consumption of fruits and vegetables significantly reduces the risk of cardio-vascular disease. This beneficial effect on the human organism is ascribed to the antioxidant compounds these foods contain. Unfortunately, many products, particularly vegetables, need to be subjected to thermal processing before consumption. The aim of this study was to determine the effect of such thermal treatment on the antioxidant capacity and pigment contents in separated fractions of violet pigments (betacyanins) and yellow pigments (betaxanthins and betacyanins). Fractions of violet and yellow pigments were obtained by separation of betalain pigments from fresh roots of 3 red beet cultivars using column chromatography and solid phase extraction (SPE). The betalain pigment content was determined in all samples before and after thermal treatment (90°C/30 min) by spectrophotometry, according to Nilsson's method [1970] and antioxidant capacity was assessed based on ABTS. Betalain pigments in the separated fractions were identified using HPLC-MS. After thermal treatment of betacyanin fractions a slight, but statistically significant degradation of pigments was observed, while the antioxidant capacity of these fractions did not change markedly. Losses of betacyanin content amounted to 13-15% depending on the cultivar, while losses of antioxidant capacity were approx. 7%. HPLC/MS analyses showed that before heating, betanin was the dominant pigment in the betacyanin fraction, while after heating it was additionally 15-decarboxy-betanin. Isolated fractions of yellow pigments in red beets are three times less heat-resistant than betacyanin fractions. At losses of yellow pigment contents in the course of thermal treatment reaching 47%, antioxidant capacity did not change markedly (a decrease by approx. 5%). In the yellow pigment fractions neobetanin was the dominant peak in the HPLC chromatogram, while vulgaxanthin was found in a much smaller area, whereas after heating additionally 2-decarboxy-2,3-dehydro-neobetanin was detected. Both groups of betalain pigments (betacyanins and betaxanthins) exhibit antioxidant capacity before and after heating. Violet beatacyjanins are 3 times more stable when heated than yellow betaxanthins.

Changes in bioactive compounds and oxidative enzymes of fresh-cut pomegranate arils during storage as affected by deficit irrigation and postharvest vapor heat treatments.

The effect of postharvest vapor heat treatments at 95℃ (4, 7, and 10 s) regarding a conventional sanitizing treatment with 100 mg NaClOl-1 on enzyme activities (phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase), phenolic content, and total antioxidant capacity of fresh-cut pomegranates arils throughout 18 days at 5℃ was studied. Furthermore, the effect of two sustained deficit irrigation (SDI) strategies, compared to a standardly irrigated control (CTRL), was also studied on such quality parameters throughout storage. Arils from CTRL-irrigated fruit registered phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase initial activities of 60.6, 382, and 14.4Ug-1fw, respectively. Arils from sustained deficit irrigation fruit registered 46-58% lower phenylalanine ammonia lyase values while polyphenol oxidase and peroxidase activities did not register great variants (<9%) among both sustained deficit irrigation treatments. Postharvest vapor heat treatments enhanced phenylalanine ammonia lyase activity in those samples from sustained deficit irrigation fruit although no great peroxidase and polyphenol oxidase (<2-5%) increases were observed. Arils from SDI1 fruit registered higher phenolic content than those values reported for CTRL samples. However, phenolic compounds decreased during storage, in a greater extent for sustained deficit irrigation samples, although 7 s arils achieved better phenolic compounds retention in sustained deficit irrigation samples. Vapor heat treatments reduced up to twofold the total antioxidant capacity losses observed in samples sanitized by conventional NaOCl treatment during shelf life. Conclusively, postharvest vapor heat treatment for 7 and 10 s used to extend the shelf life of pomegranate arils up to 18 days at 5℃ reduced the losses of health-promoting compounds during storage compared to conventional NaOCl sanitizing treatment.

The effect of fruit cultivar/origin and storage time on sorbets quality

Abstract Fruit quality is one of the main factors that influence the sorbets’ quality. The aim of this study was to evaluate the effects of two different cultivars of five fruits (mandarin, lemon, melon and mango) or origin (strawberries) on the overall quality of sorbets, right after being produced and after being preserved for 21 days at −18 °C. Total soluble solids (TSS), titratable acidity (TA) and firmness were used to characterize the fruits. Colour, pH, antioxidant capacity (AC) and total phenolic content (TPC), as well as sensory attributes, were evaluated on fruits and respective sorbets. Fruit processing led to a loss of TPC and AC. Nevertheless, no significant changes were observed on sorbets over storage time. In spite of chemical, physical and sensorial differences registered among fruits from different cultivars or origin, the sensory profiles of sorbets from the same pair of studied fruits are very similar. Multivariate analysis clearly shows that the sorbets produced maintain the same sensorial quality regardless of the cultivar or the origin of the fruits.

Quality of Banana Puree During Storage: a Comparison of High Pressure Processing and Thermal Pasteurization Methods

The quality features of banana puree after high pressure processing (HPP) at 500 MPa for 10 min and thermal pasteurization (TP) at 90 °C for 2m in during 30 days of refrigerated storage were com- pared in this study. Initial counts in banana puree of greater than 3.80 log colony-forming units (CFU)/g of total aerobic bacteria (TAB) and 3.10 log CFU/g of molds and yeasts (M&Y) were reduced by HPP and TP. TAB were approximately 1.0 CFU/g, and M&Y were less than 0.3 log CFU/g in HPP- and TP- processed puree during storage. HPP and TP did not change pH, titratable acidity (TA), total soluble solids (TSS), lightness (L), and yellowness (b), total phenolic content (TPC), and antioxidant capacity (AC), but HPP raised redness (a) and TP reduced a and ascorbic acid (AA). During storage, L, a ,a ndb in HPP- and TP- processed purees did not change but HPP-processed pu- ree increased pH and decreased TA. After storage, the percentage of TPC and AA was 75.85 and 55.09 % in the HPP group and 96.30 and 68.09 % in the TP group, indicating a significant loss of TPC and a greater loss of AA in HPP-processed puree. The loss of AC agreed with the loss of AA and TPC. HPP preserved particle size distribution and viscosity of purees, whereas TP increased the number of smaller particles and viscosity after processing and in storage. Twenty-six volatiles (18 esters) and 22 volatiles (15 esters) were detected in HPP- and TP-processed purees, and the ester fraction was 69.79 and 52.36 %, respectively. HPP was found to be an effective alternative pasteurization method for preserving the quality of fresh banana puree.

Phenolic composition, antioxidant capacity and hexanal content of hazelnuts (Corylus avellana L.) as affected by different storage conditions

The effect of five different storage conditions on the total phenolic content (TPC), the antioxidant capacity (AC), the phenolic compound profile, the total amount of quantified phenolics, the hexanal content, and the sensory characteristics of hazelnuts of two cultivars (Tonda Gentile Trilobata or TGT and Delisava—harvest 2010 and 2011) were investigated for two consecutive years. The storage variables were time (0, 4, 8 and 12 months), temperature (ambient temperature, refrigeration at 5°C, or frozen at −25°C) and O2 availability (ambient air, vacuum or modified atmosphere). Comparing the cultivars, Delisava exhibited the highest levels of TCP and AC for both harvests and all storage conditions; however, it was characterized by the highest hexanal content (more than sixfold higher than TGT). At the end of the storage, the TPC and AC decreased with respect to day 0 in both cultivars, with AC losses ranging between 12% and 35% and TPC losses of approximately 15%. However, these parameters were not able to distinguish the storage conditions. The hazelnut phenolic compound profiles did not seem to be affected by storage techniques in either cultivar; additionally, the sensory analysis panellists were not able to discriminate between the storage conditions. Hexanal was confirmed to be a good marker of lipid oxidation, and its content generally increased during storage in both cultivars; nevertheless, changes were well-controlled by storage conditions where low temperature and reduced oxygen worked synergistically. The absence of oxygen seemed to be more relevant with respect to low temperature, and a good preservation of raw hazelnut kernels was achieved by storage under vacuum with or without preliminary nitrogen flushing.

Chlorogenic acid retention in white and purple eggplant after processing and cooking

The stability of vegetable antioxidants in response to processing and cooking treatments may be affected by the variety. However, the information available in the literature is very limited. In this work we determined the influence of the eggplant variety (white – cv ‘Cloud Nine’ and purple – cv ‘Lucia’) on pulp chlorogenic acid content (5-O-caffeoyl-quinic acid; CQA) and antioxidant capacity (AC) in response to common pre-processing (cutting, salting or blanching), processing (air-vacuum- solar- and freeze-drying, slow- and fast-freezing) and cooking methods (microwaving, baking, grilling, steaming, boiling or pressure cooking). Fresh purple ‘Lucia’ eggplants showed higher AC and CQA content (16%) than white ‘Cloud Nine’ fruit. Fruit pre-processing caused significant losses of AC, with the effect being higher in the purple cultivar. Hot air- and sun-drying almost depleted CQA in both cultivars. In contrast, white eggplants retained higher AC upon freezing and microwaving. Wet cooking methods (boiling and pressure cooking) markedly increased fruit AC indicating that these preparation procedures improved antioxidant extractability. The eggplant cultivar has a major influence in antioxidant retention during processing and cooking; the white variety ‘Cloud Nine’ proved in general, more suitable for processing in terms of antioxidant retention than the purple ‘Lucia’ genotype.

Interaction of Carbon Nanomaterial Fullerene (C60) and Microcystin-LR in Gills of Fish Cyprinus carpio (Teleostei: Cyprinidae) Under the Incidence of Ultraviolet Radiation

One of the most widely used carbon nanomaterials is fullerene (C60), a lipophilic organic compound that potentially can behave as a carrier of toxic molecules, enhancing the entry of environmental contaminants in specific organs. Microcystins (MC) are cyanotoxins very toxic for human and environmental health. Several studies showed that exposure to MC or C60 generates reactive oxygen species (ROS) and changes in antioxidant levels. Also, another factor that can come to enhance the toxic potential of both MC and C60 is UVA radiation. Therefore, it was evaluated the effects on oxidative stress parameters of ex vivo co-exposure of MC and C60 (5 mg/l) in gills of the fish Cyprinus carpio under UVA radiation incidence. The results showed that (a) there was a loss of antioxidant capacity after low MC concentration (L, 50 μg/l) + C60 co-exposure under UVA, (b) C60 under UVA decreased glutathione-S-transferase (GST) activity, (c) high MC concentration (H, 200 μg/l) + C60 co-exposure decreased the concentrations of glutathione (GSH) under UVA or in the dark, (d) L under UVA increased lipid peroxidation, and (e) C60 did not cause a higher bioaccumulation of MC in gills. The lowering of GSH in H + C60 co-exposure should compromise MC detoxification mediated by GST, although toxin accumulation is not influenced by C60.