Optimization of ultrasonic-assisted extraction of phenolic compounds from <Emphasis Type="Italic">Justicia spicigera</Emphasis> leaves

A Box–Behnken design (Extraction-time, pulse-cycle, sonication-amplitude) was employed to extract phenolic compounds from Justicia spicigera leaves by ultrasonic-assisted extraction. The muicle leaves extracts were analyzed measuring total phenolic compounds and antioxidant capacity. According to response surface methodology the optimal conditions of ultrasonic-assisted extraction to obtain the highest soluble phenolic content were 2 min (extraction time) for 0.7 s (pulse cycle) at 55% of sonication amplitude. Under these optimal conditions, the total phenolic content was higher when was used ultrasonic-assisted extraction (54.02 mg/g) than stirring (46.46 mg/g) and thermal decoction (47.76 mg/g); however, the antioxidant capacity from J. spicigera extracts did not increase by ultrasonic-assisted extraction. The extracts or aqueous infusions from J. spicigera leaves are used for therapeutic proposes, therefore the ultrasonic-assisted extraction is a useful technology to improve the extraction of phytochemicals from J. spicigera leaves.     

Design of Sonotrode Ultrasound-Assisted Extraction of Phenolic Compounds from <Emphasis Type="Italic">Psidium guajava</Emphasis> L. Leaves

Psidium guajava L. has gained a special attention as health plant due to the presence of phenolic compounds. Box-Behnken design (BBD) has been applied for the extraction of target compounds from guava leaves via sonotrode ultrasound-assisted extraction (UAE). Different extraction times (5, 30, and 55 min), ratios of ethanol/water (50, 75, and 100% (v/v)), and ultrasound (US) power (80, 240, and 400 W) were tested to find their effect on the sum of phenolic compound (SPC), flavonols and flavan-3-ols via HPLC-ESI-QqQ-MS, and antioxidant activity (DPPH and TEAC assays). The best process conditions were as follows: 40 min, 60% ethanol/water (v/v), and 200 W. Established method has been used to extract phenolic compounds in two guava leaves varieties (pyrifera and pomifera). Pyrifera var. showed greater values of the SPC via HPLC-ESI-QqQ-MS (49.7 mg/g leaf dry weight (d.w.)), flavonols (12.51 mg/g d.w.), flavan-3-ols (7.20 mg/g d.w.), individual phenolic compounds, and antioxidant activity (8970 ± 5 and 465 ± 6 μmol Trolox/g leaf d.w, respectively) than pomifera var. Conventional extraction showed lower amounts of phenolic compounds (7.81 ± 0.03 and 4.64 ± 0.01 mg/g leaf d.w. for flavonols and flavan-3ols, respectively) in comparison to the ultrasound-assisted ones.     

A comprehensive study of polyphenols contents and antioxidant potential of 39 widely used spices and food condiments

Spices and condiments are rich sources of potent antioxidants. In the present investigation, total equivalent antioxidant capacities (TEAC) of 39 spices were studied using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging, and cupric reducing antioxidant capacity (CUPRAC) assays. Their total phenolic contents (TPC) and total flavonoid contents (TFC) were also determined. TEAC, TPC, and TFC varied significantly (P?<?0.05) among these spices. ABTS, DPPH, and CUPRAC assay values of studied spices ranged from 1.42 to 112.94 mg ascorbic acid equivalents (AAE)/g, 1.14 to 91.09 mg Trolox equivalents (TE)/g, and 0.52 to 54.47 mg TE/g, respectively (dry weight basis; DW). Based on Folin–Ciocalteu assay, TPC ranged from 2.93 to 160.55 mg of gallic acid equivalents (GAE)/g DW. Strong correlations between TPC and TEAC values (R?=?0.966, 0.825, and 0.954 for ABTS, DPPH, and CUPRAC, respectively) were found. This indicates that phenolic compounds are potent antioxidants in these spices. Principal component analysis (PCA) indicated that cloves (flower buds of Syzygium aromaticum) had the most distinct and potent antioxidant capacity, followed by allspice (fruits of Pimenta dioica) and cinnamon (bark of Cinnamomum verum). Results of the present study provide adequate evidence that polyphenols are responsible for their compelling antioxidant capacities of studied spices. Thus, consumption of antioxidant-rich spices such as cloves, allspice, and cinnamon can significantly prevent oxidative stress in the human body.     

Antioxidant Activity and Determination of Phenolic Compounds from <Emphasis Type="Italic">Eugenia involucrata</Emphasis> DC. Fruits by UHPLC-MS/MS

Fruits have been the focus of several studies aimed at finding new antioxidant sources for protection against the damage caused by reactive species. In this study, the antioxidant activity and the presence of phenolic compounds in all parts (peel, pulp, and seeds) of Eugenia involucrata DC. fruits were evaluated. DPPH^·, ABTS^·+, and ORAC methods were used to determine the antioxidant activity, and an UHPLC-MS/MS method was developed for determining the phenolic compounds (gallic, chlorogenic, ferulic, p-coumaric and ellagic acids, quercetin, and myricetin). In the determination of both antioxidant activity and phenolic composition, the efficiency of solvents with different polarities—methanol/H₂O (80:20, v/v), ethanol/H₂O (80:20, v/v), methanol/acidified water with phosphoric acid pH 3.00 (80:20, v/v), and ethyl acetate—for the extraction of the phenolic compounds, was also evaluated. All parts of E. involucrata fruits showed antioxidant activity, in the range of 36.68 ± 1.44 to 873.87 ± 18.24 μmol TE g^?1, being the highest values found in the seeds and peel when more polar extraction solvents were used. Six, five, and three phenolic compounds were identified and quantified in the pulp, peel, and seeds, respectively, with the highest abundance as p-coumaric acid (14 ± 2 mg kg^?1) in the pulp, quercetin (47 ± 5 mg kg^?1) in the peel, and gallic acid (74 ± 4 mg kg^?1) in the seeds, also when more polar solvents were used. Although antioxidant activity methods suggested that the peel and seeds have more antioxidant potential, a wider variety of compounds were determined in the pulp.     

Changes in the antioxidant capacity and phenolic compounds of <Emphasis Type="Italic">maesil</Emphasis> extract during one-year fermentation

This study aimed to identify the effects of soaking time and fermentation temperature and period on the total phenolics, total flavonoids, and antioxidant activity of maesil extract. Green maesil fruits were fermented with brown sugar at 15 or 25°C for one year. After soaking maesil for 90 days, the fruits were removed and the remaining liquid was further ripened for 275 days, whereas other samples continued to ferment with maesil until 365 days. Total phenolics, total flavonoids, and antioxidant activities of the extracts fermented with maesil for one year were higher compared with those wherein the fruits were removed at day 90. The total phenolic and total flavonoid contents were relatively higher at 15°C, whereas the ABTS and ferric-reducing antioxidant power (FRAP) activities were significantly higher at 25°C. The total phenolic and total flavonoid contents highly correlated with the antioxidant activities. These results show that fermentation temperature plays a critical role in enhancing the phenolic compounds and antioxidant activity of maesil extract.     

Extraction and in vitro antioxidant capacity evaluation of phenolic compounds from pigmented aromatic rice (<Emphasis Type="Italic">Oryzae sativa</Emphasis> L.) cultivars

The aroma generating volatile components profile and in vitro antioxidant capacities of different aromatic rice cultivars was determined by GC–MS analysis and in terms of DPPH scavenging activity, lipid peroxidation inhibition, phosphomolybdenum reduction and reducing power assay. The total phenolic content including both free and bound forms in the analyzed aromatic rice cultivars, Mushki budgi (1.62 mg GAE/g), Mushki kandi (1.63 mg GAE/g) and Kamad (1.60 mg GAE/g) were found double the amount as compared to non-aromatic Koshkari (0.86 mg GAE/g) cultivar. The aromatic rice cultivars had also shown higher total flavonoid content and antioxidant activity than non-aromatic rice cultivar (Koshkari). The GC–MS results indicated 21-aromatic compounds present in sufficient quantities in aromatic cultivars and some of them were unique to these cultivars. Among the compounds identified, aldehydes were found in higher quantity followed by alkanes, ketones and esters. Among the aromatic rice cultivars, Mushki budgi and Mushki kandi were found possessing higher quantity of flavoring components such as benzaldehyde, a carcinostatic agent. The cultivars Mushki budgi and Mushki kandi indicated positive correlation of TPC, TFC and the in vitro antioxidant components largely, while the less aromatic Kamad, correlate with only two components viz DPPH and lipid peroxidation.     

Characterization of phenolics in different parts of selected <Emphasis Type="Italic">Capparis</Emphasis> species harvested in low and high rainfall season

The stem bark, shoot, fruit, flower and root from Capparis spinosa and Capparis decidua, harvested in April and September (corresponding to low and high rainfall season, respectively), were investigated for variations in the contents of total phenols, flavonoids and individual phenolics. Aqueous methanol (80%) soluble extracts from different parts of the selected species, were evaluated colorimetrically for total phenolic contents (TPC), total flavonoid contents (TFC) and inhibition of linoleic acid peroxidation. Relatively, a higher extract yield (5.57–42.43%), TPC (157.3–348.6 GAE mg/100 g), TFC (229.2–584.9 CE mg/100 g) for both the species were recorded for September samples. Among the parts tested of both the species, fruits offered higher content of total phenolics (235.1–455.3 GAE mg/100 g) whereas flowers contained greater amount of flavonoids (96.7–269.9 CE mg/100 g). A notably variable content of phenolic compounds (0.24–94.22 mg/100 g) such as gallic acid, p-coumaric acid, caffeic acid, p-hydroxybenzoic acid and sinapic acid were detected by RP-HPLC in different parts of the selected species; however, sinapic acid was not detected in the flowers of both the species. It can be concluded from the findings of the present study that season has significant effect on the phenolics profiling of Capparis plants and thus collection of different parts of the selected species in an appropriate season can be beneficial towards maximizing their functional food and nutraceutical benefits.     

Optimization of Extraction Parameters of Total Phenolics from <Emphasis Type="Italic">Annona crassiflora</Emphasis> Mart. (Araticum) Fruits Using Response Surface Methodology

In this study, response surface methodology was used to optimize the extraction temperature (25–75 °C) and ethanol concentration (0–70 %, ethanol/water, v/v) to maximize the extraction of total phenolic compounds (TPC) from araticum pulp. The efficiency of the extraction process was monitored over time, and equilibrium conditions were reached between 60–90 min. A second-order polynomial model was adequately fit to the experimental data with an adjusted R ² of 0.9793 (p < 0.0001) showing that the model could efficiently predict the TPC content. Optimum extraction conditions were ethanol concentration of 46 % (v/v), extraction temperature of 75 °C and extraction time of 90 min. Under the optimum conditions, the araticum pulp showed high TPC content (4.67 g GAE/100 g dw) and also high antioxidant activity in the different assays used (46.56 μg/mL, 683.65 μmol TE/g and 1593.72 μmol TE/g for DPPH IC₅₀, TEAC and T-ORAC_FL, respectively). From our extraction procedure, we successfully recovered a significantly higher amount of TPC compared to other studies in the literature to date (1.5–22-fold higher). Furthermore, TPC and antioxidant activity were present in the fruit in levels that are difficult to find in other common fruits. These results expose a potential approach for improving human health through consumption of araticum fruit.     

Chitosan Controls Postharvest Decay and Elicits Defense Response in Kiwifruit

Chitosan is an eco-friendly alternative to synthetic fungicides for managing postharvest decay of fruits and vegetables. The ability of chitosan to enhance resistance to postharvest gray (Botrytis cinerea) and blue mold (Penicillium expansum) in kiwifruit was investigated. The gene expression and activity of antioxidant enzymes, and total phenolic compounds were determined. Results showed that chitosan at 5 g/L significantly inhibited gray and blue mold in kiwifruit stored at 25 and 4 °C. Chitosan significantly induced the gene expression of catalase, superoxide dismutase, and ascorbate peroxidase, as well as increased the enzyme activity. Moreover, chitosan markedly increased the content of total phenolic compounds in kiwifruit. Importantly, chitosan also exhibited beneficial effects on fruit quality. Taken together, the ability of chitosan to reduce mold in stored kiwifruit may be associated with the elicitation of host defense response. These results have practical implications for the application of chitosan to reduce postharvest losses.     

Characterization of nutritionally important phytoconstituents in bitter melon (<Emphasis Type="Italic">Momordica charantia</Emphasis> L.) fruits by HPLC–DAD and GC–MS

Bitter melon (Momordica charantia L.) is the traditional vegetable used as medicinal food, in different parts of the world, including Korea and China. Little is known about its bioactive composition aside from its health-promoting properties. Therefore, the present work aimed to determine the content of carotenoids, tocopherols, folates and fatty acids in bitter melon fruits. Using HPLC–DAD, six major carotenoids were quantified in fruits; all-E-lutein was recorded in highest quantity, followed by all-E-β-carotene and α-carotene, with 79.5, 17.6 and 1.5 % of total carotenoids, respectively. A high content of α-tocopherol (42.93 μg/g FW) and total folate (0.724 µg/g FW) was also recorded in fruits using HPLC–DAD and microbiological assay, respectively. The total lipid content of 1.79 % was recorded in fresh fruits (FW). Using GC–MS, sixteen fatty acids were identified in lipid fraction; α-linolenic acid (ALA; C18:3) was found in highest quantity (44.33 %) followed by palmitic acid (C16:0) (29.64 %), and linoleic acid (C18:2) (10.32 %). Melon fruits contain a low amount of saturated fatty acid and high-mono and polyunsaturated fatty acids, in the form of ALA. Knowledge of bioactive composition in bitter melon fruit will be useful for proper diet recommendations and also for nutrient database updating.     

Antioxidative Effect of Seaweed Extracts in Chilled Storage of Minced Atlantic Mackerel (<Emphasis Type="Italic">Scomber scombrus</Emphasis>): Effect on Lipid and Protein Oxidation

In this study, antioxidant activity of absolute ethanol, 50 % ethanol and water extracts of two species of seaweeds namely, Fucus serratus and Polysiphonia fucoides were evaluated for their ability to retard lipid and protein oxidation in minced mackerel. Mackerel mince added with 0.5 g/kg of extracts was prepared. For comparison, BHT at 0.2 g/kg and a control with no added extracts were also prepared. The samples were stored at 5 °C for 8 days, and sampling was done at time 0, 1, 2, 4, 5 and 8 days. The 50 % ethanolic extracts of P. fucoides were found to be very effective in retarding lipid and protein oxidation, as it resulted in low levels of peroxide value, volatiles and carbonyl compounds and protected against the loss of α-tocopherol and tryptophan residues. In spite of the higher phenolic content, the absolute ethanol extracts of both species showed a pro-oxidative tendency in minced mackerel. Water extract with lowest phenolic content showed no antioxidant effect in minced mackerel. In conclusion, the 50 % ethanolic extracts of P. fucoides can be a potential source of natural antioxidants, as these extracts have antioxidant activities similar to synthetic antioxidants such as BHT. However, the extent of protection offered by these extracts against protein oxidation was not clear and further studies are needed to understand the nature of the interaction between proteins and these extracts.     

Response surface optimization of conditions for debittering of white mahlab (<Emphasis Type="Italic">Prunus mahaleb</Emphasis> L.) juice using polystyrene resins

In the current study, debittering of white mahlab (Prunus mahaleb L.) juice using polystyrene resins was investigated and optimized using the Box–Behnken response surface methodology. The effects of independent variables including resin type (cation exchange resin, anion exchange resin, and 50:50 cation/anion exchange resin), resin dosage (0.05, 0.075, and 0.1 g/mL) and agitation speed (50, 150, and 250 rpm) on total phenolic content, total flavonoid content, total anthocyanin content (TAC), antioxidant activity, and bitterness of white mahlab juice were studied. Effects of resin type and dosage were found to be significant (p < 0.05) for all responses. A dosage of 0.05 g/mL of the anion exchange resin and an agitation speed of 250 rpm were selected as the optimum conditions based on minimum bitterness (2.42) and maximum TAC (0.018 g/mol). We could conclude that the anionic resin can greatly reduce the intensity of bitterness and maintain the composition and characteristics of the P. mahaleb juice.     

Bioactive compounds and antioxidant activities of sprout soybean fermented with <Emphasis Type="Italic">Irpex lacteus</Emphasis> mycelia

To enhance the biological activities of sprout soybean, beans were treated with steaming (SS), germinating (GS), or roasting (RS) prior to fermentation with Irpex lacteus mycelia for 20 days. The total phenolic, flavonoid, isoflavone, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of each fermented bean preparation were examined every 5 days for 20 days. The total phenolic content of SS, GS, and RS preparations was 9.61, 10.23, and 10.46 mg/g, respectively, after 15 days of fermentation. These concentrations were approximately 4–5 folds higher compared to initial levels. The total flavonoid content was 8–9 folds higher than initial levels. The isoflavone content was highest in the RS sample (6.84 mg/g). The DPPH radical scavenging activity of beans fermented with I. lacteus mycelia was increased 2–8 folds after 20 days of fermentation. These results indicate that antioxidant activity components were increased by fermentation of I. lacteus mycelia irrespective of soybean treatments.     

Reversed-phase HPLC determination of mangiferin,isomangiferin and hesperidin in <Emphasis Type="Italic"> Cyclopia </Emphasis>and the effect of harvesting date on the phenolic composition of <Emphasis Type="Italic"> C. genistoides</Emphasis>

A reversed-phase HPLC method for separation of polyphenols in honeybush tea (Cyclopia spp.) is presented. Separation of eriodictyol, luteolin, medicagol, formononetin, mangiferin, isomangiferin, hesperetin and hesperidin was investigated. A C12 stationary phase was required to separate mangiferin and isomangiferin. The method was used to quantify the three major polyphenols (mangiferin, isomangiferin and hesperidin) in C. genistoides, C. intermedia, C. maculata and C. sessiliflora and to study the effect of harvesting date on these compounds in two types of C. genistoides. The highest levels of the xanthones, mangiferin (3.61 g/100 g) and isomangiferin (0.54 g/100 g), and the flavanone, hesperidin (1.74 g/100 g), were found for C. genistoides (both xanthones) and C. intermedia, respectively. Cyclopia sessiliflora contained the lowest levels of mangiferin (1.04 g/100 g) and hesperidin (0.29 g/100 g). The mangiferin content of both the Overberg and West Coast types decreased with harvesting date (P <0.05). The Overberg type contained more mangiferin, but hesperidin was more prominent in the West Coast type.     

Bioactive components and antioxidant capacities of different miniature tomato cultivars grown by altered fertilizer applications

This study investigated the organic acid and phenolic compound levels, total phenolic (TP) and antioxidant capacity (TEAC) of three miniature tomato cultivars grown on a farmer’s field with three different fertilizer applications. Analysis of phenolic compound (protocatechuic, vanillic, gallic, chlorogenic, caffeic, syringic, p-coumaric and ferulic acid, rutin, quercetin, catechin and phloridzine) organic acid (citric, tartaric, malic, succinic and fumaric acid), TP and TEAC levels in fruit samples showed statistically significant (p?<?0.05) differences between tomato cultivars and fertilizer applications. Rutin and chlorogenic acid were the predominant phenolic compounds found in all three cultivars. The highest rutin value (50.48 mg kg^?1 FW) was found in the Black Zebra fertilized with DAP plus organic and biochemical fertilizers and the lowest (20.52 mg kg^?1 FW) in the Black Zebra fertilized with DAP only. The highest chlorogenic acid value (63.31 mg kg^?1 FW) was found in the sweet pea currant fertilized with DAP only and the lowest (21.06 mg kg^?1 FW) in the Black Zebra fertilized with DAP plus chemical fertilizer. Citric acid content was the dominant organic acid in all three cultivars, with the highest citric acid value (6439.50 mg kg^?1 FW) found in the Sweet Pea Currant cherry tomato fertilized with DAP plus organic and biochemical fertilizers and the lowest (2435.20 mg kg^?1 FW) in the Window Box Yellow fertilized with DAP plus chemical fertilizer. Total phenolic and antioxidant levels in the window box yellow were significantly lower as compared to the Black Zebra and sweet pea currant varieties for all three fertilizer applications.     

Antibacterial activities of a cinnamon essential oil with cetylpyridinium chloride emulsion against <Emphasis Type="Italic">Escherichia coli</Emphasis> O157:H7 and <Emphasis Type="Italic">Salmonella</Emphasis> Typhimurium in basil leaves

This study examined the antibacterial activities of two different cinnamon essential oil emulsions against Escherichia coli O157:H7 and Salmonella Typhimurium on basil leaves. Cinnamon oil (0.25%) treatments containing CPC (0.05%) exhibited greater effects on the pathogenic bacteria than cinnamon oil treatment without this emulsifier (p < 0.05). Treatment with cinnamon bark and leaf oil emulsions (CBE and CLE, respectively) reduced the populations of E. coli O157:H7 by 4.10 and 5.10 log CFU/g, and S. Typhimurium by 2.71 and 2.82 log CFU/g, respectively. Scanning electron micrographs showed morphological changes in the two pathogenic bacteria following emulsion treatment. In addition, there was no difference in the color or ascorbic acid content of the basil leaves by the emulsion treatment. These results suggest that CBE or CLE treatment can be an effective way to ensure the microbial safety of minimally processed vegetables and a good alternative to chlorination treatment in the fresh produce industry.     

A comparative study on cytotoxicity and antiproliferative activities of crude extracts and fractions from Iranian wild-growing and cultivated <Emphasis Type="Italic">Agaricus</Emphasis> spp.

Little is known about anticancer capability of wild-growing mushrooms belonging to Agaricus spp. in comparison with their cultivated counterparts. The present study was done to evaluate in vitro antiproliferative effects of dichloromethane-methanol (1:1, v/v) extracts obtained from several Iranian wild strains of Agaricus spp. in comparison with the cultivated white button mushroom, A. bisporus. The wild brown A. bisporus at 500 µg/mL moderately prevented the growth of human prostate cancer (PC3) and human breast cancer (MCF-7) cell lines by 23.54 and 24.57%, respectively, while the wild strains of A. devniensis and A. gennadii at 500 µg/mL had only marginal inhibitory effects. On the contrary, the cultivated A. bisporus significantly inhibited the cell growth at concentrations as low as 125 µg/mL (p?<?0.05). Further, seven distinct fractions were determined based on thin layer chromatography analysis of the cultivated A. bisporus extract. The only active fraction was found to be eluted by petroleum ether (PE):ethyl acetate (EtOAc) (3:2 v/v) which prevented the growth of MCF-7 and PC3 by 74.00 and 63.5%, respectively at 500 µg/mL. Besides, the fraction imposed obvious cytopathic effects in both cell lines at all the tested concentrations, starting from 125 µg/mL. The findings of this study may validate that the known antioxidant potency of wild Agaricus spp. would not necessarily be correlated to their anticancer activity. This research further validated that some semi-polar antiproliferative compounds could be present in the PE/EtOAc-fraction of the cultivated white button mushroom, which warrants further investigations.     

Optimization of Ultrasound-Assisted Extraction of Lycopene from Papaya Processing Waste by Response Surface Methodology

Lycopene possesses strong antioxidant ability, which may provide protection against cancer and other degenerative diseases. An ultrasound-assisted extraction method has been developed for the extraction of lycopene from papaya (Carica papaya L.) processing waste. Optimization conditions were firstly determined using single factor experiment, and then response surface methodology was used. Analysis showed that second-order polynomial models produced a satisfactory fitting of the experimental data with regard to lycopene (R ²?=?0.9147, P?<?0.001). The optimal conditions were 42.28 % ethanol in ethyl acetate as a solvent and extraction for 26.09 min at 50.12 °C. Under these conditions, the maximum yield of lycopene was 189.8?±?4.5 μg/g fresh weight (FW), which was higher than that obtained using the traditional extracting method (153.9?±?7.8 μg/g FW) and the Soxhlet extraction method (68.3?±?4.1 μg/g FW). The crude extract obtained could be used as either food additive or for further isolation and purification of lycopene. The results obtained are helpful for full utilization of papaya.     

Ultrasound-assisted extraction and antioxidant activity of phenolic and flavonoid compounds and ascorbic acid from rugosa rose (<Emphasis Type="Italic">Rosa rugosa</Emphasis> Thunb.) fruit

The present study aimed to extract total phenolic compounds (TPC), total flavonoid compounds (TFC), and ascorbic acid (AA) from the fruit of rugosa rose (Rosa rugosa Thunb.) by ultrasound-assisted extraction (UAE), and to evaluate their antioxidant activities. UAE significantly increased the extract yield compared with that obtained using the conventional method. TPC, TFC, and AA were extracted, depending on the extraction conditions (temperature, time, and ethanol concentration), in the range of 50.73–96.69, 15.93–31.88, and 3.06–6.08 mg/g, respectively. TPC and TFC were effectively extracted at a relatively high temperature (50 °C) than AA was (30 °C). The solvent condition used to extract TPC, TFC, and AA was 50% ethanol. The UAE condition for the highest antioxidant activity was obtained 30 °C, 30 min, and 50% ethanol, which were the same condition for the highest AA extraction. Among the extracts, AA showed a strong correlation with antioxidant activity at p-value of 0.001.     

Effects of High-Pressure Processing with or without Blanching on the Antioxidant and Physicochemical Properties of Mango Pulp

The effects of high-pressure processing (HPP 300 MPa/15 min, 400 MPa/5 min, 500 MPa/2.5 min, and 600 MPa/1 min) and high-temperature/short-time processing (HTST 110 °C/8.6 s), with or without blanching, on mango pulp were comparatively evaluated in terms of the antioxidant compounds, antioxidant capacity, sugars, and color. Blanching treatment significantly increased the total phenol content and the antioxidant capacity of mango pulp, but did not change the levels of L-ascorbic acid, carotenoids, sugars, and visual color (total color difference, △E?<?2.00). Both HPP and HTST treatments significantly increased the total phenol content and antioxidant capacity of un-blanched mango pulp, but no significant changes occurred in the blanched mango pulp. HPP did not affect the levels of L-ascorbic acid, carotenoids, and sugars in mango pulp regardless of blanching. However, HTST significantly decreased the fructose and glucose levels, as well as induced the isomerization of β-carotene, with the increase in 13-cis-β-carotene accompanied by the decrease in all-trans-β-carotene. Moreover, HPP-treated mango pulp consistently showed lower △E values than those HTST-treated samples, regardless of blanching.