Retention Of Antioxidant Capacity Research Articles

Innovative strategies in yacon drying: Ethanol pretreatment and intermittent microwave drying.

The yacon roots are rich in fructooligosaccharides (FOS) and highly perishable. Drying is crucial for food quality and extending shelf life. However, preserving thermosensitive compounds, such as FOS, poses a challenge in conventional drying methods. In this regard, microwave drying and ethanol pretreatment (ET) have emerged as promising solutions for maintaining nutrients and reducing drying time (DT). The objective of this study was to assess how ET and sample temperature affect quality and process parameters during intermittent microwave drying of yacon. Drying at 52°C treated with ethanol was the one that stood out for presenting the highest fructan retention (64.1%), low DT, lower energy consumption (EC) (364.00±5.03kWhkgwater-1), higher retention of antioxidant capacity (73.9%) and total phenolic content (77.5%), and slight variation in color parameters. Therefore, microwave drying with a controlled temperature of yacon pretreated with ethanol effectively reduces DT and EC by maintaining quality parameters.

Effect of liposomal encapsulation of curcumin and α-tocopherol on sensory and physicochemical properties, and retention of antioxidant capacity of fortified cookies during baking

Curcumin and α-tocopherol, which are potent antioxidants usable for food fortification, are sensitive to heat and air, thus showing the need for protection. The aim of this study was to increase the antioxidant capacity retention of curcumin and α-tocopherol in fortified cookies via liposomal encapsulation. Liposomes were prepared using the homogenization method and the liposomes were multilamellar according to light microscopic images. Liposomal encapsulation exhibited encapsulation efficiencies greater than 90 %. The sensory tests, conducted using a 5-point hedonic scale for nine attributes, revealed that the incorporation of liposomal antioxidants did not compromise the sensory attributes of the cookies. The color of liposomal-curcumin incorporated cookie deviated greater than that of free-curcumin incorporated cookie from the regular cookie. Nevertheless, the color of the α-tocopherol incorporated cookies improved on using the liposomal compound as opposed to the free compound. The antioxidant capacity of the cookies, along with the controls, was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. As expected, liposomal encapsulation of curcumin or α-tocopherol mitigated the reduction of antioxidant capacity of fortified cookies during baking. Briefly, liposomal encapsulation proves to be a potent method for retaining the antioxidant capacity of curcumin or α-tocopherol in cookies during baking.

Phenolic and antioxidant capacity retention of potato peel waste as a function of cultivar, pretreatment and drying procedure

Drying procedures employed for potato peels (both raw and boiled) may adversely affect the useful bioactivecomponents present in them. This study envisaged the identification of a feasible drying procedure for handlingbulk potato peel waste for maximising the retention of phytochemicals in the peel powder. The total phenols (TP), flavonoids (TF) and antioxidant capacity (TAC) were assessed in peels of three commercial and one newly developed anthocyanin rich Indian potato cultivars in response to boiling pretreatment and varying drying procedures. Microwave drying (600W) was best in terms of drying rate for both raw and boiled peels. It yielded the greatest amount of TP and TF in the dried raw peel, irrespective of cultivar. Dried raw peels of an thocyanin rich Kufri Neelkanth cultivar exhibited maximum TAC. Retention of TF, metal scavenging activity and reducing power followed almost a similar pattern as TP irrespective of cultivar, pretreatment and drying procedure. Our study shows that potato peel from Kufri Neelkanth (raw) and Kufri Frysona (both raw and boiled) are best source of phenolics and flavonoids and can serve as a suitable matrix for extraction of bioactive compounds which holds promise for use in the food industry.

Retention of phenolic compounds and acceptability of gluten-free churros made with tannin or tannin-free sorghum flour

Abstract: The objective of this work was to evaluate the acceptability of gluten-free churros made either with tannin or tannin-free sorghum flour, as well as the retention of their phenolic compounds and antioxidant capacity retention after cooking and frying. The churros were developed by replacing wheat flour with sorghum flour from the sorghum cultivars BRS 305 with tannin (T-churro) or BRS 501 tannin free (TF-churro). The content of phenolic compounds and antioxidant activity were evaluated before and after the thermal processing. Both products had a high acceptability (84.5‒95.5%) for all evaluated sensory attributes, and no difference was observed for color, aroma, and flavor. However, the T-churro showed a higher acceptance for texture, overall acceptability, and purchase intention. The churros had a similar proximate composition for fiber content. The phenol content was about three times and antioxidant activity about 20 times higher for T-churro than for TF-churro. Although subjected to two types of processing (cooking and frying), the fried and ready-to-eat T-churro retained more than 50% of anthocyanins, phenols, and antioxidant activity. The TF-churro product showed a retention of these compounds above 70, 40, and 65%, respectively. The tannin content of 'BRS 305' sorghum increases its functional potential and does not negatively affect the acceptability of the churros. Sorghum either with or without tannins has the potential to be used for the production of gluten-free churros.

Bioactive Characteristics and Storage of Salt Mixtures Seasoned with Powdered Cereal Sprouts

Sprouting is a process that can improve nutritional and beneficial properties of seeds. This work studies the design of the new healthier product salt seasoned with freeze-dried powdered cereal sprouts. The cereal sprouts mixture (SM), including barley sprouts (BS), oat sprouts (OS), and wheat sprouts (WS), was optimized in terms of total phenolic content (TPh) and antioxidant capacity (AC). The sprouts mixture with optimal features (OSM), composed of 92.9% BS, 0% OS, and 7.1% WS, had 482.82 mg GAE/100 g of polyphenols and 797.97 µmol TE/100 g antioxidant capacity. HPLC analysis showed that the most abundant phenolic compound in OMS was gallic acid (94.27 mg/100 g). OSM was mixed with salt in different ratios (1 : 1, 1 : 2, and 1 : 3) and stored in transparent and amber bottles for six months. Colour, TPh, and AC retention of seasoned salts and OSM was significantly better (p<0.05) preserved in amber bottles during storage, protected from light. The sprout content was in correlation with TPh and AC retention and colour change. These results suggest that cereal sprouts can be used as a safe ingredient for food products such as seasoned salt, adding value to the basic daily diet with no changes in dietary habits.

Effect of Thermosonication on the Bioaccessibility of Antioxidant Compounds and the Microbiological, Physicochemical, and Nutritional Quality of an Anthocyanin-Enriched Tomato Juice

The aim of this study was to assess the potential of thermosonication as a strategy to obtain safe and high-quality tomato juice enriched in anthocyanins, formulated using strawberry processing co-products. Incorporation of strawberry press cake into the tomato juice resulted in higher polyphenolic and anthocyanin content and increased antioxidant capacity. Thermosonication for 5 min at 60 °C at either 35 or 130 kHz resulted in higher microbial inactivation when compared to thermal pasteurisation at 80 °C for 1 min. In addition, thermosonication allowed increased retention of colour attributes as well as polyphenol, lycopene, anthocyanin, and antioxidant capacity retention when compared to thermal treatment. For example, the total anthocyanin content decreased from 1.08 ± 0.04 mg/100 mL before processing to 0.92 ± 0.01 mg/100 mL after thermal pasteurisation but the difference was not significant when compared with the thermosonicated juice (1.06 ± 0.03 mg/100 mL). Although bioaccessibility of phenolic compounds after a simulated gastrointestinal digestion was lower in processed juices, thermosonicated samples showed a higher bioaccessibility when compared to the thermally treated ones.

Microencapsulation of Purple Cactus Pear Fruit (Opuntia ficus indica) Extract by the Combined Method W/O/W Double Emulsion-Spray Drying and Conventional Spray Drying: A Comparative Study

The aim of this study was to microencapsulate an optimized extract of purple cactus pear fruit (Opuntia ficus indica), rich in phenolic compounds (PC), betacyanins (BC), and betaxanthins (BX), with antioxidant capacity (AC), by two methodologies: combined water-in-oil-in-water double emulsions-spray drying (W/O/W-SP) and conventional spray drying, studying the effect of spray drying (SP) on PC and AC. Optimal extraction conditions for bioactive compounds were: 52 °C, for 30 min, using aqueous ethanol (40%w/w) as the solvent, with a 0.85 desirability function, obtaining 17.39 ± 0.11 mg GAE/gdw (gallic acid equivalents per gram of dry weight) for PC, 0.35 mg BE/gdw (betanin equivalents per gram of dry weight) for BC, and 0.26 mg IE/gdw (indicaxanthin equivalents per gram of dry weight) for BX. The best combination of temperatures for conventional SP and W/O/W-SP was 160–80 °C obtaining the highest retention and encapsulation efficiencies for PC. For conventional SP, results were: 107% and 100% PC and AC retention efficiencies (RE-PC and RE-AC), respectively, with 97% of PC encapsulation efficiency (EE-PC), meanwhile for the W/O/W-SP results were: 78% and 103% RE-PC and RE-AC, respectively, with 70% of EE-PC. Microcapsules obtained with W/O/W-SP maintained their structure and integrity and showed a considerable reduction in globule size in the reconstituted W/O/W emulsions due to the spray drying stress. Despite having lower EE-PC than conventional SP, spray dried W/O/W emulsions seem as a promising controlled-delivery vehicle for antioxidant compounds.

Turmeric (Curcuma longa L.): new application as source of fiber and antioxidants in pasta with whole wheat flour

La demanda de alimentos saludables para la prevención de enfermedades no transmisibles ha aumentado, y los desarrollos incluyen ingredientes con efectos en la salud, como harina de trigo de grano entero y cúrcuma. Ambos son adicionados en el presente estudio como fuente de fibra y antioxidantes en pasta. El trabajo tuvo como objetivo evaluar el efecto de la adición de harina de cúrcuma en pasta con harina de trigo de grano entero y harina de trigo refinada, en su contenido de fibra y las propiedadestecnológicas y antioxidantes. Para esto, se realizaron tres pastas control con trigo de grano entero entre 600 y 700 g kg-1. Adicionalmente, siete pastas de cúrcuma se prepararon de acuerdo con un diseño experimental lineal (22), con tres puntos centrales. Los análisis tecnológicos incluyeron test de cocción, color y textura. Un Análisis de Componentes Principales se realizó para seleccionar dos formulaciones para pruebas bromatológica y de capacidad antioxidante. Las pastas seleccionadas fueron CP3 (70 WGF: 30 RWF) y TP3 (5 g TF, 60 WGF: 40 RWF), que presentaron propiedades tecnológicas similares y alto contenido de fibra dietaria (74.3 g kg-1). TP3 presentó el mayor contenido de fenólicos totales(534.46 ± 1.93 mg kg-1), DPPH• (5.70 ± 0.10 g kg-1 Trolox Equivalente (TE)), y ABTS (9.02 ± 0.58 g kg-1 TE), con alta retención de la capacidad antioxidante después de cocción. La harina de cúrcuma promovió el cambio en color de las pastas con WGF, acentuando la tonalidad amarilla y manteniendo laspropiedades de cocción; por tanto, es un ingrediente natural que confiere color y compuestos fenólicos en productos con WGF.

Effect of extraction method and thermal processing on retention of bioacvtive compounds of pomegrante (Punica granatum) (cv. Bhagwa) juice

The effect of juice extraction methods (from arils and halved fruits), temperature (70, 80, 90 and 100ÌŠC) and thermal processing time (2, 5 and 10 minutes) on quality of the pomegranate (Punica granatum L.) juice has been studied. The quality parameters studied included biochemical parameters such as ascorbic acid, total anthocyanin content, total phenolic compounds, antioxidant capacity, TSS, and acidity. The color, microbial, and sensory qualitywas also evaluated. The results revealed that thermal treatment reduces important bioactive compound with increase in temperature and time of processing. The thermal processing at 80 ÌŠC for 5 min. found to be suitable for reducing microbial load to below detectable limits and maintaining sensory quality up to 7.91 on ten point hedonic scale. The juice extracted from halved fruits was found to be nutritionally rich than juice extracted from arils in terms of antioxidant capacity, ascorbic acid, total phenolic compounds, total anthocyanin and color value a*. The retentionof antioxidant capacity, total phenolic compounds,total anthocyanin content, ascorbic acid and color for thermal processing at 80 ÌŠC for 5 minutes for juice extracted from halved fruits was 22.68 mg/100ml AAE, 2189 mg/l GAE, 3.18 mg/100 ml, 18.33 mg/100 ml and 37.05 respectively.

Impact of vacuum cooking and boiling, and refrigerated storage on the quality of galega kale (Brassica oleracea var. acephala cv. Galega)

Physicochemical parameters, bioactive compound contents and antioxidant capacity were evaluated and compared in fresh samples of Galega kale and samples cooked by boiling and different vacuum cooking procedures. The effect of refrigerated storage for 21 days was also studied in relation to the different vacuum cooking treatments. The impact on chemical and quality parameters depended on the cooking method used. Boiling caused lower loss of soluble solids and vitamin C than vacuum cooking. Vacuum cooking in an autoclave led to greater retention of antioxidant capacity, total phenolics, chlorophyll and colour. In general, losses during storage were higher in kale samples cooked by the vacuum cooking method in an autoclave than in those cooked by the same method in a water bath. The study findings demonstrate that vacuum cooking could be used as an alternative to conventional methods of cooking kale.

Evaluating Modified Tannin Esters as Functional Additives in Polypropylene and Biodegradable Aliphatic Polyester

Esterified and native condensed tannins have been evaluated in polypropylene and the aliphatic polyester Bionolle. Tannin esters at typical plastic additive loadings have minimal effect on plastic mechanical properties. In assessing functional equivalence tannin esters inhibit the effects of UV degradation in both polypropylene and Bionolle with tannin hexanoate acetate having greater efficacy than a synthetic UV stabiliser at comparable loading. Oxidative induction testing also suggests the tannin esters can act to prevent oxidative degradation of polypropylene. However, retention of antioxidant capacity was crucial to inhibiting oxidative degradation. Outcomes suggest bio‐based tannin additives have potential to substitute synthetic additives and improve plastic sustainability credentials.

Comparison of microwaves and conventional thermal treatment on enzymes activity and antioxidant capacity of kiwifruit puree

Enzymes are naturally present in food and can cause product deterioration. For this reason, most food-processing steps try to reduce the enzymatic activity. The aim of this work was to compare, in terms of both the inactivation of kiwifruit puree peroxidase, polyphenoloxidase and pectinmethylesterase and also the maintenance of the antioxidant capacity of the product, the effect of a microwave treatment with a conventional thermal treatment designed to cause the same level of peroxidase inactivation (90%). The microwave power and process time that best permitted the maximisation of both the enzyme inactivation and the antioxidant capacity of the product, were selected by means of the Response Surface Methodology. The results obtained point to microwave heating as an appropriate technology with which to produce a stable kiwifruit puree, since these treatments were more effective at enzyme inactivation and antioxidant capacity retention than the conventional thermal treatment. Food industry is currently focused on the development of novel and minimally processed products with improved quality. Traditional thermal processing has been assumed to require the use of high temperatures and long times to stabilise food products, which lead to dramatic losses of products' quality. Thus, a variety of different processing technologies are being explored as alternative to traditional thermal processing. The results of this study point out that more than conventional heating, microwave technology can be an appropriate means of achieving the required level of enzyme inactivation at which to obtain a stable kiwifruit puree with an improved antioxidant capacity.

Effect of temperature on hot-air drying rate and on retention of antioxidant capacity in apple leathers

Fruit leathers are pectic gels, eaten as snack or dessert, obtained by dehydrating fruit purees. In this work, apple leathers were prepared by a hot-air drying process which allows the formation of a gel, following the “saccharide–acid–high methoxyl pectin” gelation mechanism. Leathers were produced at 50, 60 and 70°C, from two formulations: control and added with potassium metabisulphite (KM) as antioxidant. The drying process was studied applying a diffusive model, while antioxidant capacity (AC) losses were represented by a first-order model. Activation energy for drying (20.6kJ/mol) was lower than those estimated for AC losses in control (31.5kJ/mol) and KM-added (37.9kJ/mol) leathers. Therefore, the drying time reduction achieved by increasing air temperature is not sufficient to decrease AC losses in the range covered. AC retention decreased in both formulations at increasing air temperature. KM-added samples showed higher AC retention than the controls, except for those dried at 70°C. Kinetic constants were lower for KM-added samples, suggesting a protective effect of the additive, especially at moderate air temperatures. In the most favorable situation, AC retention was of only 16%. Therefore, the functional character of these products may not be preserved if dried with hot air and the research on economically viable, less-severe drying technologies should be intensified.

Effects of blanching pre-treatment and sugar composition of the osmotic solution on physico-chemical, morphological and antioxidant characteristics of osmodehydrated blueberries (Vaccinium corymbosum L.)

The effect of a steam blanching preconditioning step was investigated on the chemical, nutraceutical and morphological characteristics of osmo-dehydrated blueberries (Vaccinium corymbosum L.) in sucrose or glucose/fructose osmotic solutions. Mass transfer phenomena (solid gain, water loss and sugar gain) were monitored into the samples at intervals over a 24-h period of osmodehydration. The antioxidant capacity of untreated and osmo-dehydrated fruits was evaluated by total phenolics, total and individual anthocyanins and antioxidant activity (amperometric method), while colorimetric (luminance) and morphological (area, shape factor, fractal dimension) characteristics of the berries were determined by image-analysis technique. Results showed that the blanching step increased mass transfer phenomena in the course of the osmodehydration treatments (approx +55% solid gain and +33% water loss) and reduced the loss of phenolic compounds, improving the retention of antioxidant capacity in the final product (from approx 66.9–56.9% in not blanched berries to 88.6–95.7% in blanched ones). Blanched berries had also deeper colour and smoother surface. Slight differences in mass balances and in the final composition of berries could be ascribed to the kind of osmotic solution used.

Retention of Antioxidant Capacity of Vacuum Microwave Dried Cranberry

In this study, cranberries were dried by vacuum-microwave drying (VMD), freeze-drying (FD), or hot air-drying (AD), to compare the effects of different drying processes on both physical changes as well as the retention of bioactive components in dried samples. Total porosity (%) and average pore radius of dehydrated cranberries were greater using VMD compared to FD and AD (P < 0.05). Crude methanol cranberry powdered extracts were fractionated by solid phase extraction (SPE) into organic acid-, total phenolics-, anthocyanin-, or proanthocyanidin-enriched extracts, respectively. The chemical composition of the 60% acidified methanol fractions contained cyanidin-3-galactoside, cyanidin-3-arabinoside, peonidin-3-galactoside, and peonidin-3-arabinoside, as assessed by HPLC. Antioxidant activities of cranberry fractions were measured using chemical ORAC and ABTS methods. The 60% acidified methanol fraction had a significantly higher (P < 0.05) antioxidant potential than the other chemical fractions, which was largely attributed to the relatively higher anthocyanin content. In general, vacuum-microwave drying and freeze-drying resulted in similar retention of anthocyanins and antioxidant activity, which were both relatively higher (P < 0.05) than that recovered from cranberries dried by hot air drying.

Effects of high-intensity pulsed electric field processing conditions on lycopene, vitamin C and antioxidant capacity of watermelon juice

Abstract Watermelon juice was subjected to high-intensity pulsed electric fields (HIPEF). The effects of process parameters including electric field strength (30–35 kV/cm), pulse frequency (50–250 Hz), treatment time (50–2050 μs), pulse width (1–7 μs) and pulse polarity (monopolar/bipolar) on lycopene, vitamin C and antioxidant capacity were studied using a response surface methodology. Lycopene content was measured spectrophotometrically, vitamin C was determined by HPLC and antioxidant capacity through the inhibition of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical. Watermelon juice exhibited high retention of lycopene and antioxidant capacity when high electric field strengths, frequencies and pulse widths were applied. However, severe HIPEF treatments reduced vitamin C content. Maximal relative lycopene content (113%), vitamin C (72%) and antioxidant capacity retention (100%) were obtained when HIPEF treatments were set up at 35 kV/cm for 50 μs using 7 μs bipolar pulses at 200 Hz.

Modeling changes in health-related compounds of tomato juice treated by high-intensity pulsed electric fields

Changes in some health-related compounds (lycopene and vitamin C) and antioxidant capacity of tomato juice treated by high-intensity pulsed electric fields (HIPEF) were modeled as a function of the electric field strength and treatment time. Samples were subjected to electric field strengths from 20 to 35 kV/cm for up to 2000 μs using bipolar 1-μs pulses at 250 Hz. Weibull kinetic models predicted vitamin C and antioxidant capacity retention of HIPEF-treated tomato juice with good accuracy ( R adj 2 ⩾ 0.836; A f = 1.001–1.010). A model used to describe moisture sorption processes was the most accurate for describing lycopene changes through the HIPEF treatment time. The combined effect of treatment time and electric field strength on health-related compounds of tomato juice were successfully predicted ( R adj 2 > 0.948 ; A f = 1.016–1.017) through secondary expressions. Information from this study would be useful in determining optimal HIPEF-conditions to produce tomato juices with a high retention of bioactive compounds.

Lycopene, Vitamin C, and Antioxidant Capacity of Tomato Juice as Affected by High-Intensity Pulsed Electric Fields Critical Parameters

The effects of high-intensity pulsed electric field (HIPEF) treatment variables (frequency, pulse width, and pulse polarity) on the lycopene, vitamin C, and antioxidant capacities of tomato juice were evaluated using a response surface methodology. An optimization of the HIPEF treatment conditions was carried out to obtain tomato juice with the highest content of bioactive compounds possible. Samples were subjected to an electric field intensity set at 35 kV/cm for 1000 micros using squared wave pulses, frequencies from 50 to 250 Hz, and a pulse width from 1 to 7 micros, in monopolar or bipolar mode. Data significantly fit (P < 0.001) the proposed second-order response functions. Pulse frequency, width, and polarity significantly affected the lycopene, vitamin C, and antioxidant capacities of HIPEF-treated tomato juice. Maximal relative lycopene content (131.8%), vitamin C content (90.2%), and antioxidant capacity retention (89.4%) were attained with HIPEF treatments of a 1 micros pulse duration applied at 250 Hz in bipolar mode. Therefore, the application of HIPEF may be appropriate to achieve nutritious tomato juice.

Inactivation of polyphenol oxidase in muscadine grape juice by dense phase-CO2 processing

Abstract The effect of dense phase-CO2 processing (DP-CO2) on polyphenol oxidase (PPO) activity, polyphenolic and antioxidant changes in muscadine grape juice under different processing pressures (27.6, 38.3, and 48.3 MPa) and CO2 concentrations (0, 7.5, and 15%) were measured. Subsequently two DP-CO2 conditions (48.3 MPa at 0 or 15% CO2) were evaluated for polyphenolic and antioxidant changes during storage (4 °C, four weeks). Pressure alone was responsible for a 40% decrease in PPO activity that resulted in 16–40% polyphenolic and antioxidant losses. Increasing CO2 from 0 to 7.5% was responsible for an additional 35% decrease in enzyme activity and a two-fold greater polyphenolic retention. However, insignificant changes in PPO activity or polyphenolic retention were observed when CO2 was increased to 15%. During storage, juices with residual PPO activity following processing resulted in greater polyphenolic (8- to 10-fold) and antioxidant capacity (four-fold) degradation compared to control juices with no PPO activity. This study demonstrated that partial PPO inactivation can be obtained by DP-CO2 and that CO2 level was the primary variable influencing PPO activity and polyphenolics and antioxidant capacity retention in muscadine grape juice.