A simplified UV spectral scan method for the estimation of phenolic acids and antioxidant capacity in eggplant pulp extracts

The objective of this study was to determine if a simple UV spectral analysis method can be used as a screening tool to estimate the amount of phenolic acid and the antioxidant capacity of eggplant pulp extracts. Calibration curves for different concentrations of 5-O-caffeoylquinic acid standards were developed using UV spectral data, HPLC analysis, and ferric reducing antioxidant power (FRAP) assay. Seven different freeze-dried eggplant pulp samples belonging to different cultivars or grown under different environmental conditions along with single peel sample were selected as model substrates for this study. HPLC results, simple UV spectral scan data, and quantification of antioxidant capacity by FRAP assay in seven eggplant pulp extracts showed a strong correlation (R² > 0.9) between the three methods. These results suggest that the single absorption reading or a simple UV spectral scan can be used to estimate the concentration of phenolic acids and the antioxidant capacity in eggplant pulp extracts without peels. This screening tool can be potentially used to identify cultivars and growing conditions that influence phenolic acid content in eggplant samples.     

Characterization of the antioxidant functions of flavonoids and proanthocyanidins in Mauritian black teas

Tea drinking is associated with an improved antioxidant status in vivo which may contribute to the lowering of the risk of certain types of cancer, coronary heart disease and stroke. The polyphenolic bioactive composition and the antioxidant properties of Mauritian commercial black and fresh tea leaves were evaluated. Hot water infusates contained high levels of total phenols, total proanthocyanidins and total flavonoids. The concentrations of individual compounds, (+)-catechin, (−)-epicatechin, (−)-epicatechin 3-gallate, epigallocatechin, (−)-epigallocatechin 3-gallate, gallic acid, and procyanidin dimers B1 and B2 were high. The ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays were used to assess the antioxidant potential of tea infusates with the following order of potency: Ouvagalia tea > Buccaneer’s choice > Black Label > Red Label > Extra > Corson > Chartreuse > La Flora > 3-Pavillons. Linear regression analyses indicated high correlation coefficient with total proanthocyanidin (TEAC r = 0.96 and FRAP r = 0.95) and total phenol contents (TEAC r = 0.90 and FRAP r = 0.92) in infusates. Catechins and gallic acid significantly contributed to the overall antioxidant capacity of black tea extracts. In general, the fresh tea leaves had high levels of total phenols, total flavonoids, total proanthocyanidin and exhibited greater antioxidant potentials when compared with black teas. Thus Mauritian black teas and fresh tea leaves can be rich sources of polyphenolic compounds and antioxidants, which may be highly relevant to the maintenance of normal health and disease management, an observation that has led to the commencement of a clinical trial study to assess cardiovascular health in Mauritius.     

Polyphenols,carotenoids, and ascorbic acid in underutilized medicinal vegetables

The polyphenols, carotenoids, ascorbic acid, and protein were determined in 24 underutilized medicinal vegetables from Indonesia. Anacardium occidentale, Sauropus androgynus (L.) Merr., and Moringa pterygosperma Gaertn. leaves were rich sources of flavonoids, with 118–144 mg/100 g fresh weight. Quercetin, kaempferol, and chlorogenic acid were the predominant polyphenols among those measured in vegetables. Polyscias pinnata leaves and Solanum torvum Swartz fruits had the most phenolic acids, with 53 and 36 mg/100 g, respectively. Moringa pterygosperma had the most carotenoids among vegetables, with 14 mg β-carotene equivalents (βCE)/100 g. Ascorbic acid content of fresh vegetables was 12.03–494.43 mg/100 g. A. occidentale, S. androgynus, Ocimum americanum L., Cosmos caudatus H.B.K., and Carica papaya L. (papaya) leaves had more than 100 mg ascorbic acid/100 g. Thus, a number of underutilized vegetables from Indonesia may be rich sources of functional components including polyphenols and ascorbic acid.     

Phytonutrient,Antioxidant and Mineral Composition of Some Wild Fruits in South West Nigeria

This study was carried out to determine the chemical composition, antinutrient and phytonutrient contents of some wild fruits, namely African star apple (Chrysophyllum albidum G. Don.), hog plum (Spondias mombin Linn.), bush mango (Irvingiagabonensis Baill) and monkey cola (Colamillenii K. Schum). Samples of the wild fruit commonly consumed were collected from some villages in Ido Local Government Area, Oyo State Nigeria. The wild fruits were analysed for phytonutrients, antioxidants and mineral composition. Ranges of total phenolics and total anthocyanin content of these wild fruits were 27.78 ± 6.01 in I. gabonensis, 57.42 ± 4.47 in S. mombin, 121.29 ± 4.97 in C. millenii and 398.23 ± 0.00 in C. albidum respectively. Significant differences (p < 0.05) were found in antinutrient, phytonutrient and mineral composition of C. albidum, I. gabonensis and C. millenii. The analysis of variance revealed that calcium and manganese contents of I. gabonensis were significantly (p < 0.05) higher than those of C. albidum and C. millenii. The antioxidants especially vitamin C content ranged from as low as 15.87 mg/100 g in C. albidum to as high as 204.86 mg/100 g in S. mombin. The values for total carotenoid ranged from 172.77 μg/100 g (in C. millenii) to 1380.17 μg/100 g (in C. albidum). The wild fruits are sources of phytonutrients, antioxidants such as vitamin C, total carotenoids and some minerals. Planting of the wild fruit trees or the incorporation in farming systems should thus be encouraged to increase production and availability to consumers and as industrial raw materials.     

Modeling the effect of natamycin,pine-resin and environmental factors on the growth and OTA production by Aspergillus carbonarius using response surface methodology

The effect of two antifungal compounds (natamycin, pine-resin), temperature and water activity, on the growth rate, lag phase duration and Ochratoxin A (OTA) production by three Aspergillus carbonarius isolates (Ac-28, Ac-29, and Ac-33), was studied by means of Response Surface Methodology (RSM) based on a Central Composite Design (CCD). Two different experimental designs were performed as a function of temperature (16.6–33.4 °C), water activity (0.90–0.97 a_w), natamycin (0–1000 ng ml^− 1) or pine-resin (0–2.61%, w/v) on a Synthetic Grape-juice Medium (SGM). OTA production was analyzed after 5, 10 and 15 days of incubation. A second-order polynomial model was fitted to each response parameter to assess the growth and OTA potential of all fungal isolates. Results showed that natamycin, a_w and temperature had significant effects on the lag phase duration of all isolates, as well as on OTA accumulation after 10 days of incubation for Ac-29 and 15 days for Ac-28 and Ac-33 isolates. The same results were obtained for OTA production after treatment with pine-resin. However, fungal growth rates were not statistically significant in both experiments, with the exception of Ac-29 and Ac-33 after treatment with pine-resin. Overall, high natamycin concentrations (800 and 1000 ng ml^− 1) delayed fungal growth depending on the environmental factors assayed. Moreover, treatment with pine-resin at 16.6 °C/0.94 a_w/1.1% w/v, as well as at 25 °C/0.90 a_w/1.1% w/v, completely inhibited fungal growth up to 15 days of incubation.     

Polyphenolic and antioxidant content of white and blue corn (Zea mays L.) products

The polyphenolic and antioxidant content of white, Mexican blue, and American blue corns processed into nixtamal (cooked kernels), tortillas, and chips was investigated. A post-nixtamalization acidification treatment was assessed as a means to reduce polyphenolic and antioxidant losses. Similar anthocyanin composition (cyanidin 3-monoglycosides) and concentration (314 mg/kg) was observed for both blue corn genotypes as was their non-anthocyanin polyphenolic composition ((+)-catechin, free and esterified ferulic acid, and p-coumaric acid derivatives). Six derivatives of ferulic acid (88.8–816 mg/kg) along with the free form (2480 mg/kg), p-coumaric acid (6.6 mg/kg), two protocatechuic acid derivatives (4.2 and 14.2 mg/kg), and gallic acid (3.9 mg/kg) were identified in the white genotype. Both blue genotypes contained higher antioxidant capacity (>8.3 μmol Trolox equivalents/g) yet lower polyphenolic levels (3.6–4.4 g/kg) than the white genotype. Comparable anthocyanin losses were observed when the blue genotypes were processed into nixtamals (37%), tortillas (54%), and chips (78%) that correlated to polyphenolic (r = 0.91) and antioxidant capacity (r = 0.94) losses. Acidification was mainly effective in reducing anthocyanin (9–17%), polyphenolic (10%), and antioxidant capacity (6–14%) losses for the blue genotypes. This study compared polyphenolic and antioxidant content among corn genotypes and confirmed that acidification post-nixtamalization could reduce polyphenolic and antioxidant losses.     

Valorisation of tomato wastes for development of nutrient-rich antioxidant ingredients: A sustainable approach towards the needs of the today's society

Nutrient-rich antioxidant ingredients were produced from tomato fruit wastes using a microwave-assisted extraction (MAE) process. Different conditions of extraction time (t), temperature (T), ethanol concentration (Et) and solid/liquid ratio (S/L) were combined in a circumscribed central composite design and optimized by response surface methodology. The model was statistically validated and used for prediction in the experimental range. Under the global optimal MAE conditions (t = 20 min, T = 180 °C, Et = 47.4% and S/L = 45 g/L), it was possible to obtain an extraction yield of 75.5% and ingredients with high levels of sugars, proteins, phenolics, and flavonoids, and interesting antioxidant properties measured via ABTS⁺ scavenging activity and oxidative haemolysis inhibition assay (OxHLIA). The antioxidant capacity of the extracts was lower compared to the one of commercial food additives. However, the sustainably developed ingredients may be used in the fortification and functionalisation of food, as well as for incorporation in feed products.Industrial relevanceThis study addresses current needs of the agri-food sector, namely the recycling of plant wastes and production of valuable extracts for the food/feed industry. A MAE process was developed and optimized to maximize the recovery of nutrients and antioxidants from tomato fruit wastes. The optimum processing conditions established in this study allowed a high extraction yield and reduced solvent consumption. MAE can be considered as a sustainable alternative to conventional extraction methods. These findings will contribute to promote a more sustainable bioeconomy in the agro-food sector.     

Bean cultivars (Phaseolus vulgaris L.) have similar high antioxidant capacity,in vitro inhibition of α-amylase and α-glucosidase while diverse phenolic composition and concentration

Common beans are a good source of essential nutrients such as protein, fiber, vitamins, and minerals; they also contain phenolic compounds and other phytochemicals. Phenolic compounds exhibit high antioxidant capacity that promotes health benefits by reducing oxidative stress. The objective was to compare the composition and quantity of anthocyanins and other non-colored phenolic compounds in fifteen improved bean cultivars from Mexico and Brazil and their relation to antioxidant capacity and enzymes related to type-2 diabetes. Samples were analyzed for total phenolic compounds (TP), flavonoids, antioxidant capacity (AC), tannins and total anthocyanins. Type and quantity were evaluated by HPLC-ESI-MS. Delphinidin glucoside (0.9–129.0 mg/100 g dry coat), petunidin glucoside (0.7–115.0 mg/100 g dry coat) and malvidin glucoside (0.14–52.0 mg/100 g dry coat). Anthocyanidins were positively correlated when quantified by HPLC and colorimetric analysis (R = 0.99). Cultivar Negro-Otomi presented the highest concentration of anthocyanins (250 mg/100 g dry coat). Seventeen non-colored phenolic compounds were identified among cultivars; catechin, myricetin 3-O-arabinoside, epicatechin, vanillic acid, syringic acid and o-coumaric acid, presented the highest concentrations among identified phenolic compounds. The AC of all fifteen bean cultivars did not show significant differences (p > 0.05) ranging from 185.2 (FM-67) to 233.9 (FM-199) mmol TE/g coat. Compounds in the coat extracts of pinto and black cultivars were the most efficient to inhibit α-amylase and α-glucosidase. Studied cultivars differed in composition and concentration of phenolics including anthocyanins; however, there was no effect on AC as measured by oxygen radical absorbance capacity. Black beans contained delphinidin and ferulic acid, compounds commonly used as ingredients in functional foods due to their associated health benefits.     

Antioxidants from a Chinese medicinal herb – Psoralea corylifolia L

The powder and extracts of Psoralea corylifolia L. were tested in lard at 100 °C by using the oxidative stability instrument (OSI) and were found to have strong antioxidant effects. Six compounds, bakuchiol, psoralen, isopsoralen, corylifolin, corylin and psoralidin were isolated from the herb and identified by UV, IR, Mass, ¹H and ¹³C NMR spectra and melting point. Their antioxidant activities were investigated individually and compared with butylated hydroxytoluene (BHT) and α-tocopherol by the OSI at 100 °C. The results showed that bakuchiol, corylifolin, corylin and psoralidin had strong antioxidant activities, and especially psoralidin (stronger antioxidant property than BHT), but psoralen and isopsoralen had no antioxidant activities at 0.02% and 0.04% levels. The antioxidant activities of the compounds decrease in the following order: Psoralidin > BHT > α-tocopherol > bakuchiol > corylifolin > corylin > isopsoralen ∼ psoralen.     

Rutin and flavonoid contents in three buckwheat species Fagopyrum esculentum,F. tataricum,and F. homotropicum and their protective effects against lipid peroxidation

This study was conducted to investigate the rutin content of three buckwheat species: Fagopyrum esculentum, Fagopyrum tataricum and Fagopyrum homotropicum, and to evaluate their antioxidant capacity. In total, 11 cultivars/accessions were analyzed. The contents of both rutin and total flavonoids were significantly different depending on species, 0.02% and 0.04% in F. esculentum, 0.10% and 0.35% in F. homotropicum, and 1.67% and 2.04% in F. tataricum, respectively. Three buckwheat species exhibited a dose–response effect in inhibiting low-density lipoprotein (LDL) peroxidation. The antioxidant activity decreased in the order: F. tataricum > F. homotropicum > F. esculentum. Linear regression analysis revealed a correlation between antioxidant activity and rutin content (R² = 0.98) or total flavonoids content (R² = 0.77) in all buckwheat cultivars/accessions. This work shows that rutin plays an important role in antioxidant activity of buckwheat seed. It provides useful information for buckwheat breeding to develop high rutin content varieties.     

Bioactive substance contents and antioxidant capacity of raw and blanched vegetables

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389–539 µg/100 g), blanched (510–818 µg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2–7.8 mg/100 g), blanched (0.67–3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene.Industrial relevanceBeans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work.     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Effects of high hydrostatic pressure on the quality and shelf-life of jujube (Ziziphus jujuba Mill.) pulp

This study evaluated the effects of high hydrostatic pressure (HHP) on the microbial counts, physicochemical properties, bioactive compounds, and antioxidant capacity of jujube pulp. Additionally, this study compared the shelf life of jujube pulp following HHP (600 MPa/20 min) and thermal treatment (100 °C/10 min) during 40 days of storage at 4 °C and 15 °C. The microbial count of HHP-treated jujube pulp (≥ 400 MPa/20 min) was below the detection limit. Total soluble solids and total sugars were not significantly affected by HHP processing, and > 90% ascorbic acid was retained in HHP-treated samples. HHP slightly reduced pH and browning degree and increased total phenolic content, flavonoid content, and antioxidant capacity. HHP can be used as an alternative to thermal pasteurization of freshly squeezed jujube pulp.Industrial relevanceEffects of high hydrostatic pressure (HHP) processing and thermal treatment (TT) on microbiological quality, physicochemical properties, bioactive compounds and antioxidant activity in jujube pulp were investigated. Greater inhibition of microorganisms and better retention of ascorbic acid, total phenolics, flavonoid and antioxidant capacity were observed after HHP-treatment. The available data could be used to design the HHP parameters for high quality jujube juice. Further, this research would provide a useful method for preservation of jujube products and potential technical support for jujube commercial production.     

Evaluation of bioactive properties of Indian carrot (Daucus carota L.): A chemometric approach

Sixteen Indian commercial carrot cultivars were analysed for variations in β-carotene, total phenolics, total flavonoids, total monomeric anthocyanin and antioxidant activity. Antioxidant activity was measured using four in vitro assays viz. ferric reducing antioxidant power (FRAP), cupric reducing antioxidant power (CUPRAC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and Trolox equivalent antioxidant capacity assays (TEAC). Additionally six colour attributes were evaluated. Among carrot cultivars, significant differences (p < 0.05) were obtained with respect to antioxidant composition and antioxidant activity. Total phenols and total flavonoids varied from 7.98 to 291.48 mg/100 g fresh weight (fw) and 3.00 to 111.70 mg/100 g fw respectively. Chemometric tools like principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were applied to understand possible classification Indian carrot cultivars based on colour properties, bioactive antioxidant compounds and antioxidant potentiality. PCA revealed that the first two components represented 92.9% of the total variability in the total variation. AHC classified cultivars into four main groups on the basis of the measured parameters. Black coloured genotype was found to be rich source of phenols, flavonoids and anthocyanin with very high antioxidant activity. Orange cultivars were found to be rich sources for β-carotene compared to red & black cultivars.     

Effects of high hydrostatic pressure on physicochemical properties,enzymes activity,and antioxidant capacities of anthocyanins extracts of wild Lonicera caerulea berry

Wild Lonicera caerulea berries were subjected to five different high hydrostatic pressure (HHP) treatments (which resemble the conditions of active component extraction and commercial sterilization). The content of anthocyanins and total phenolics increased by 6.84% and 14.35% (p < 0.05), respectively after treatment at 200 MPa for 5 and 10 min. As HHP increased, a higher loss of active component was observed. The total phenolic contents did not differ significantly between the control and the 400 MPa/20 min treated group (p > 0.05); HHP processing demonstrated better sterilization effect but severely destroyed enzymes. Polyphenol oxidase (PPO) and peroxidase (POD) activity were activated at lower HHP, such as 200 MPa, and decreased at 400–600 MPa. Superoxide dismutase (SOD) maintained good stability under HHP processing. The antioxidant capacities of anthocyanins extracts of wild L. caerulea berry were evaluated by 3 different methods (DPPH assay, oxygen radical absorbance capacity assay, and cellular antioxidant activity assay).Industrial RelevanceFactors such as color, luster, and nutrition often affect consumer choice in food. However, the color and nutrition of foods tend to be destroyed during processing and storage. The demand for healthier and more nutritious food while retaining the color and flavor after processing highlights the need to develop novel and gentler technologies for fruit processing. Recently, high hydrostatic pressure (HHP) technologies have been used in different branches of the food industry. In the present study, the content of active component in blue honeysuckle fruit pulps such as anthocyanins and polyphenols showed tendency to increase and then decrease with increasing pressure at room temperature. Five different HHP treatment groups (resembling the conditions of active component extraction conditions and commercial sterilization) were compared to the control (fresh fruit) and heat-treated group to determine the effects of HHP processing on L. caerulea berry pulps. The aim of this study was to investigate the changes in active component particularly the content and composition of anthocyanins under different high-pressure treatment at room temperature; the color and physicochemical indexes were also analyzed at the same conditions. Low HHP for a long period of time (400 MPa/20 min) demonstrated better results than that with high HHP for a short time (600 MPa/10 min), as indicated by the higher contents of anthocyanins and phenols and stronger antioxidant capacities. Therefore, Low HHP conditions can be used as an auxiliary means of active component extraction. The conditions of HHP processing at low HHP for a long period of time (400 MPa/20 min) can be altered to retain active components during food processing.     

Screening of whey protein isolate hydrolysates for their dual functionality: Influence of heat pre-treatment and enzyme specificity

Heat pre-treated and non heat pre-treated whey protein isolate (WPI) were hydrolysed using α-chymotrypsin (chymotrypsin), pepsin and trypsin. The in vitro antioxidant activity, ACE-inhibition activity and surface hydrophobicities of the hydrolysates were measured in order to determine if peptides with dual functionalities were present. Dual functional peptides have both biological (e.g. antioxidant, ACE-inhibition, opioid activities) and technological (e.g. nanoemulsification abilities) functions in food systems. Heat pre-treatment marginally enhanced the hydrolysis of WPI by pepsin and trypsin but had no effect on WPI hydrolysis with chymotrypsin. With the exception of the hydrolysis by trypsin, heat pre-treatment did not affect the peptide profile of the hydrolysates as analysed using size exclusion chromatography, or the antioxidant activity (P > 0.05). Heat pre-treatment significantly affected the ACE-inhibition activities and the surface hydrophobicities of the hydrolysates (P < 0.05), which was a function of the specificity of the hydrolysing enzyme. Extended hydrolysis (up to 24 h) had no significant effect on the DH and the molecular weight profiles (P > 0.05) but in some instances caused a reduction in the antioxidant activity of WPI hydrolysates. The chymotrypsin hydrolysate showed a broad MW size range, and was followed by pepsin and then trypsin. The bioactivities of the hydrolysates generally decreased in the order; chymotrypsin > trypsin > pepsin. This study showed that by manipulating protein conformation with pre-hydrolysis heat treatment, combined with careful enzyme selection, peptides with dual functionalities can be produced from WPI for use as functional ingredients in the manufacture of functional foods.     

Bioactive characteristics and antioxidant activities of nine peppers

The contents of bioactive compounds (Vitamin C (Vc), carotenoids, total phenolics, phenolic profiles and capsaicinoids) and antioxidant activities (reducing power, DPPH-scavenging activity and lipid peroxidation inhibition ability) of nine peppers from Yunnan province China, belonging to seven cultivars, were determined. Red and green Point pepper/Long-point pepper were from the same cultivars at different maturity stages. Results showed that all fresh pepper samples were rich in Vc, carotenoids, and total phenolics. Vc contents varied mainly depending on the pepper cultivars, except for the ripened stages. The phenolic content in red Fructus Capsici (Capsium frutescens L.) was significantly higher than that of others (Capsium annuum L.) (p < 0.05). Seven phenolics were identified in four pepper samples, while six phenolics were detected in other samples. The capsaicinoid contents of nine peppers showed a large variability, and the content in red Fructus Capsici was significantly higher than that of others (p < 0.05). The extracts of nine peppers showed high reducing power, DPPH-scavenging activity, and lipid peroxidation inhibition ability, and the activities of Fructus Capsici were significantly stronger than those of others (p < 0.05). Furthermore, antioxidant activities of nine peppers correlated well with their total phenolic contents.     

Production of nutraceutics from chestnut burs by hydrolytic treatment

Chestnut (Castanea sativa) burs (CB) were processed by solvent extraction (with ethanol, toluene–ethanol or n-hexane) and/or isothermal autohydrolysis, and the potential as nutraceutics of the solubilized fractions of dietary fiber and antioxidants was evaluated. Among the studied alternatives, the most suited consisted on ethanol extraction, which yielded 21.0 g gallic acid equivalents (GAE)/100 g ethanolic CB extract, with EC_50,DPPH = 0.38 g/L. Ethanol-extracted CB were treated with water at 120 °C, and the soluble fraction was mixed with ethanol to precipitate 8.8 g soluble fiber/100 g CB, with a Water Retention Capacity of 2.4 g/g and an oil absorption capacity of 23.7 g/g. The mother liquors from the above precipitation stage were concentrated and extracted with ethyl acetate to yield an organic phase containing soluble phenolics with high antioxidant activity (EC_50,DPPH = 0.103 g/L) at a yield of 7 g/100 g CB. When the aqueous phase before the ethyl acetate extraction was treated with sulfuric acid, an additional antioxidant fraction (EC_50,DPPH = 0.395 g/L) was obtained. The properties and characteristics of these extracts produced make them good candidates to be used as active ingredients.     

The effect of time and origin of harvest on the in vitro biological activity of Palmaria palmata protein hydrolysates

The effect of starting protein composition, and the origin and time of harvesting on the in vitro tyrosinase, dipeptidyl peptidase (DPP) IV and angiotensin converting enzyme (ACE) inhibitory and antioxidant activity of Palmaria palmata protein hydrolysates were investigated. Electrophoretic profiles showed significant differences in aqueous protein extracts obtained from the red macroalga Palmaria palmata harvested at different times of the year. No significant difference was observed in aqueous protein profiles extracted from wild and aquacultured samples of Palmaria palmata. Protein extracts from Palmaria palmata samples harvested from wild plants in April, July and October, and samples cultivated on longlines and harvested in April were hydrolysed with Alcalase 2.4 L and Corolase PP. The hydrolysates, when tested at 10 mg/ml, were shown to inhibit tyrosinase by 37–56%. The oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) values of the hydrolysates ranged from 323–494 and 8.9–19.9 μmol trolox equivalents per gram, respectively. The Palmaria palmata hydrolysates inhibited DPP-IV (IC₅₀: 1.60–4.24 mg/mL) and ACE (IC₅₀: 0.14–0.35 mg/mL) activities. The starting protein composition had a significant effect on the tyrosinase inhibitory activity, while protein composition and hydrolytic enzyme preparation had a significant effect on DPP-IV inhibitory and antioxidant activities. In general, the origin of the samples, wild or cultivated, had no effect on the in vitro biological activity of the protein hydrolysates. The results show that Palmaria palmata hydrolysates may have potential applications as health enhancing ingredients and as food preservatives due to their antioxidant and tyrosinase inhibitory effects.     

Ultrasound-assisted enzyme catalyzed hydrolysis of olive waste and recovery of antioxidant phenolic compounds

The ultrasound-assisted enzyme hydrolysis (UAEH) procedure for extraction of phenolics from olive waste (OW) was established. The optimized conditions obtained with response surface methodology (RSM) were pH 5.75, treatment 40 min and temperature 55 °C, the yield obtained reached to 4.0%. The extraction kinetics model was fitted well to the ln (C_t/C₀) = kt, and the rate constants (k) increased with the increased in the extraction temperature. Moreover, the values of k were higher and the activation energy was lower than ultrasound treatment alone. The thermodynamic parameters indicated the extraction process was easier under the UAEH. Compared with the petroleum ether and n-butyl alcohol, ethyl acetate extract fraction had high phenolic content (64.4 mg/g), especially hydroxytyrosol and tyrosol (17.2 mg/g and 14.1 mg/g), and exhibited excellent antioxidant activities in DPPH·, ABTS⁺·and FRAP assay. These finding revealed that OW could be used for a enrich source of natural phenolic compounds for development of food industry.Industrial relevanceOlive waste (OW) has been widely paid attention as sources of high-added value compounds, such as phenolic which can be obtained by the several methods. And phenolic extract as a food additive can not only improve the sensory quality of food, but also can enhance antioxidant capacity in fatty food matrices. Moreover, the use of this extract has better economic benefits than synthetic additives usually used in food industry. In this study, a novel green, simple and efficient technology was employed to extract the phenolic compounds, which was suitable for large-scale industrial use. The results indicated that ultrasound-assisted enzyme hydrolysis (UAEH) has significant potential in the extraction process of phenolics from OW exhibiting higher phenolic yield in shorter extraction times.