The phenolic compounds and the antioxidant potential of infusion of herbs from the Brazilian Amazonian region

The consumption of tea increased significantly in the past few years as a result of its health benefits as potent antioxidants in the diet. However, studies on the antioxidant compounds from Brazilian tea are scarce. Thus, the aim of this work was to evaluate the total phenolic compounds (TPC) and total flavonoids (TF) contents and the antioxidant capacity (DPPH and β-carotene/linoleic acid system) of nine herb infusions from the Amazonian region, namely agirú (Chrysobalanus icaco), açoita-cavalo (Luehea speciosa), capim-santo (Cymbopogon citratus), erva-cidreira (Lippia alba), graviola (Annona muricata L.), jucá (Libidibia ferrea), pata-de-vaca (Bauhinia ungulata), parirí (Fridericia chica) and sacaca comum (Croton spp.). These herbs were chosen based on popular knowledge and consumption. C. ferrea (68.13 mg GAE/g), L. speciosa (47.54 mg GAE/g) and C. icaco (51.30 mg GAE/g) presented the highest TPC contents, while L. speciosa (12.85 mg CE/g) and L. alba (15.42 mg CE/g) showed the highest TF contents. The highest antioxidant capacity, using both assays, was shown by L. ferrea. The three herbs with the highest TPC contents were selected to be analyzed by high performance liquid chromatography (HPLC) coupled to a diode array detector (DAD). A commercial green tea (Camellia sinensis) was also analyzed as a reference. The main compounds tentatively identified were gallic acid (0.45 mg/g), myricetin (0.78 mg/g) and quercetin (0.14 mg/g) in C. icaco; (+)-catechin (1.20 mg/g) and quercetin (0.14 mg/g) in L. speciosa; gallic acid (0.59 mg/g) and quercetin (0.13 mg/g) in C. ferrea; and gallic acid (0.24 mg/g), (−)-epicatechin (2.44 mg/g), (+)-catechin (0.68 mg/g) and quercetin (0.66 mg/g) in green tea. Among the nine studied herbs, the importance of L. ferrea should be pointed out since it presented the highest TPC content and antioxidant capacity and its gallic acid content was much higher than that of green tea.     

Gluten-free cookies added with fibre and bioactive compounds from blackcurrant residue

A blackcurrant by-product of juice production was dehydrated and added to a gluten-free chocolate cookies formulation as a source of dietary fibre and antioxidants. The blackcurrant ingredient showed high bioactive compounds content: total phenolics (TPC) = 37.5 ± 0.9 mg GAE per g d.b., total monomeric anthocyanins = 18.0 ± 0.4 mg cyanidin-3-glucoside per g d.b., antioxidant activity (AA) = 22.1 ± 0.3 mg GAE per g d.b. and total dietary fibre (TDF) = 32.3 ± 0.4% d.b. The cookie formulation was added with 3.75% blackcurrant powder without causing severe organoleptic changes. The cookies presented 62% and 70% increase of TPC and AA, respectively. The in vitro digestion showed that a relevant level of AA could reach the large intestine. Also, the TDF increased 2.5 times, reaching a final content that would enable the use of the claim 'source of dietary fibre' in the labelling according to the Codex Alimentarius. The obtained cookies showed a high level of acceptance among coeliac and non-coeliac consumers in the sensory analysis.     

Spray-Drying of Antioxidant-Rich Blueberry Waste Extracts; Interplay Between Waste Pretreatments and Spray-Drying Process

This study aimed to establish an efficient route for converting blueberry waste material (BWM) into antioxidant-rich powders. Extracts were produced from BWM by an aqueous method using water acidified with citric acid, in the absence or presence of Pectinex Ultra SP-L and Cellubrix. All BWM extracts contained antioxidants including phenolic acids, anthocyanins, and flavonoids (total phenolic content (TPC) 3655–4369 mg gallic acid equivalent (GAE) and total anthocyanin content (TAC) 219–296 mg cyanidin-3-glucoside equivalents (CyGE) per 100 g dry extract). Extractions at 50 °C yielded higher TPC and TAC but lower vitamin C and pectin contents than extractions at 20 °C. Spray-drying BWM extracts produced at 50 °C (no enzymatic treatments) and an encapsulant (alginate or inulin) at an inlet temperature 150 °C and feed temperature 50 °C yielded powders with desired dark purplish blue color, water activity (0.25–0.33), flowability, reconstitution time (23–46 s in water or milk), TPC (25–30 mg GAE/g), TAC (17–20 mg CyGE/g), storage stability, and Bifidobacterium-boosting properties. Enzymatic pretreatments of BWM did not confer any advantages in preserving antioxidants in powder products, suggesting that some intrinsic BWM components (e.g., pectins) may play an important role in the encapsulating process. The use of alginate as the encapsulant/drying aid afforded higher powder yields, superior protection of antioxidants, better stability over a prolonged storage or elevated temperature storage, greater retention of TPC/TAC under simulated gastrointestinal conditions, and greater Bifidobacterium-boosting effects, compared to powders prepared using inulin. Thus, simple aqueous extraction methods and spray-drying technology hold enormous promise for producing antioxidant-rich powders from blueberry processing by-products or waste.     

In vitro gastrointestinal digestion of mango by-product snacks: Potential absorption of polyphenols and antioxidant capacity

Mango by-products are considered cheap sources of valuable foods and nutraceutical ingredients. In this work, antioxidant capacity (AOX), and potential absorption ability (PAA) of extractable polyphenols (EP) from mango by-product snacks (MB-S) were evaluated at different stages of in vitro gastrointestinal digestion. A wheat and oat-based control snack and three MB-S formulations (F1, F2 and F3) were prepared. Mango by-products were added at the expense of wheat in MB-S (paste-peel-seed): F1 (70-30-0), F2 (70-15-15), F3 (70-7.5-22.5). The highest release of polyphenols was observed after the gastric digestion. In the intestinal stage, MB-SF1 was the snack with the highest EP content (23.39 mg GAE/g db), two times greater than the control. Gallic acid and mangiferin were the main polyphenols identified in MB-S. The incorporation of mango seed in the MB-S reduced the polyphenols PAA by 10.29%. However, compared with the control snack, consumption of 30 g MB-SF1 provided additional 45 mg polyphenols.     

Characterisation of oleoresins extracted from tomato waste by liquid and supercritical carbon dioxide

Tomato waste is characterised by high amounts of bioactive compounds, such as carotenoids, polyphenols and essential fatty acids. In this work, oleoresins were produced from tomato waste (skins + seeds) and skins using carbon dioxide under liquid and supercritical conditions. The use of ethanol as a co-solvent was also evaluated. Compositions of the oleoresins were analysed and compared to oleoresin obtained by means of an organic solvent, which was used as the control. Oleoresin extraction from the waste by liquid and supercritical CO₂ provided the highest yields (12.5%–12.9%). The extracts obtained from the skins with supercritical CO₂ without ethanol had the highest content of α- and γ-tocopherols (80 and 575 mg/100 g oleoresin, respectively), while lycopene and β-carotene were found at 205 and 75 mg/100 g oleoresin, respectively. The highest quantity of polyphenols (9305 mg GAE/100 g oleoresin) was found in the oleoresin extracted from skin by supercritical CO₂ with ethanol. All oleoresins were characterised by a high antioxidant activity, which improved with the synergy of carotenoids, tocopherols and polyphenols.     

Bioaccessibility and antioxidant activity of phenolic compounds in cooked pulses

The aim of this study was to evaluate the bioaccessibility of polyphenols and antioxidant activity in cooked pulses and to study the effect of cooking on their total phenolic content (TPC) and antioxidant capacity. Cooked faba beans showed the highest TPC, followed by soybeans and lentils or peas. TPC ranged from 10.4 ± 0.2 to 52.9 ± 0.3 mg/100 g and was positively correlated with antioxidant activity. Cooking resulted in increased TPC and antioxidant activity of the methanolic extracts, caused by cell disruption and improved extraction of polyphenols. Although polyphenols were lost in the cooking water, boiled legumes had more polyphenols than those resulting cooking broths. In vitro gastrointestinal digestion resulted in increased TPC and antioxidant capacity of the extracts. Soybeans showed the highest amount of bioaccessible polyphenols. The release of phenolics from cooked legumes was mainly achieved during the intestinal phase. Literature data may underestimate the TPC and antioxidant capacity of pulses.     

Antioxidant activity of three edible seaweeds from two areas in South East Asia

Total phenolic content (TPC) and antioxidant activity (AOA) of 50% aqueous methanol extracts of the marine algae, Padina antillarum, Caulerpa racemosa and Kappaphycus alvarezzi were studied. TPC was measured using Folin-Ciocalteu method while 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), ferrous ion chelating (FIC) assay and beta carotene bleaching (BCB) assay were used to study their AOA. P. antillarum was found to have the highest TPC, 2430±208 mg gallic acid equivalents (GAE) per 100 g dried sample and ascorbic acid equivalent antioxidant capacity (AEAC), 1140±85 mg AA/100 g. C. racemosa and K. alvarezzi displayed lower TPC and AEAC. C. racemosa had 144±22 mg GAE/100 g dried sample of TPC and 14.3±2.0 mg AA/100 g of AEAC, while K. alvarezzi had 115±35 mg/100 g dried sample of TPC and 37.8±16.8 mg AA/100 g of AEAC. In addition, P. antillarum displayed the highest reducing power, 15.7±2.6 mg GAE/g and highest chelating ability. C. racemosa and K. alvarezzi exhibited lower reducing power, 0.737±0.423 mg GAE/g and 0.561±0.269 mg GAE/g, and lower chelating ability. However, the AOA of these three seaweeds as assessed by BCB assay were equally high.     

Recovery of bioactive compounds from walnut (Juglans regia L.) green husk by supercritical carbon dioxide extraction

In this work, the use of supercritical carbon dioxide, a nontoxic solvent, was proposed to extract bioactive compounds from Juglans regia L. green husk and was compared to other traditional techniques based on solvents such as ethanol, methanol and water. Supercritical CO₂ was combined with ethanol as an organic modifier at a rate of 20% of the total flow to achieve greater extraction of polar compounds. The extracts were characterised in terms of extraction yields, antioxidant activity, total polyphenol content, phenolic acids, juglone, volatile organic compounds and antifungal activity. The results showed that the extracts obtained with supercritical CO₂ were rich in polyphenols (10750 mg GAE/100 g) and juglone (1192 mg/100 g) and exerted high antioxidant activity and antifungal activity compared with the tested fungi. Walnut green husk is not just a food industry waste but also an important economic source of bioactive compounds that could be used for food active packaging.     

Enhancing the nutritional value of cold-pressed oilseed cakes through extrusion cooking

The most abundant oilseed cakes, soybean, rapeseed/canola, and sunflower, and especially those from cold-pressing, contain meaningful amounts of antinutritional polyphenols that limit their potential as plant protein sources. The objective of this study was to remove polyphenols, and especially sinapic and chrologenic acid derivatives in canola and sunflower, respectively, using pilot-scale extrusion, and without compromising the nutritional and the technological quality of the protein fraction. Extrusion significantly increased the ratio of soluble to insoluble dietary fiber from 0.45 to 0.58 in canola and from 0.19 to 0.31 in sunflower, whereas the opposite was found in soybean (0.52 to 0.36). Canola (67.7 mg GAE/g) and sunflower (58.9 mg GAE/g) exhibited large quantities of polyphenols, which mostly consisted of sinapic and chlorogenic acid derivatives, respectively. Extrusion increased the proportion of free polyphenols and did not significantly reduce the amount of sinapic acid derivatives in canola. On the contrary, extrusion decreased the content of free polyphenols in sunflower by 68%. Generally, the extrusion conditions shown in this study resulted in limited protein denaturation and aggregation and a moderate decrease in β-sheet structures (up to 59%), which led to similar liquid holding capacity and enhanced protein solubility. Extrusion notably increased the gastric protein hydrolysis of soybean cake, but it negligibly affected that of canola and sunflower counterparts, possibly due to the counteracting effect of indigestible quinone-protein adducts. Extrusion is a promising technology to reduce polyphenols meaningfully in certain oilseed cakes while retaining or improving protein quality.     

Phenolic composition and antioxidant activity of white mulberry (Morus alba L.) fruits

Eight major mulberry cultivars [Nakhonratchasima 60 (NS 60), Buriram 60 (BR 60), Chumphon (CP), Wavee (WV), Chaingmai (CM), Pikultong (PT), Kamphaengsaen (KS) and Kamnanchul (KJ)] cultivated in Thailand were assessed for their flavonoid and phenolic acid composition using HPLC and tested for antioxidant potential using 2,2‐diphenyl‐1‐picrylhydrazyl hydrate (DPPH) assay. The total phenolic content (TPC) ranged from 104.78 to 213.53 mg GAE/100 g DW, and total flavonoid content (TFC) ranged from 69.58 to 211.01 mg CE/100 g DW. The major flavonoid compounds in mulberry fruit cultivars were (+)‐catechin (309.26–750.01 mg/100 g DW), procyanidin B1 (62.59–224.41 mg/100 g DW), quercetin (5.36–58.42 mg/100 g DW), rutin (18.73–26.90 mg/100 g DW) and (?)‐epicatechin (8.47–29.21 mg/100 g DW). Gallic acid, cinnamic acid and p‐hydroxybenzoic acid were found to be the major phenolic acids in mulberry fruit cultivars. The gallic acid and cinnamic acid contents ranged from 7.33 to 23.90 mg/100 g DW and from 11.64 to 15.05 mg/100 g DW, respectively. p‐Hydroxybenzoic acid content ranged from 1.77 mg/100 g DW (PT) to 7.13 mg/100 g DW (KJ). DPPH‐scavenging ability was excellent for ethanolic extract of NS 60, and EC₅₀ value of NS 60 (241.83 μg mL^?1) was significantly lower than those of the others (P < 0.05). TPC and TFC of the mulberry fruit were positively correlated with the DPPH‐scavenging ability.     

Antioxidant activity and phenolic content of pressurised liquid and solid–liquid extracts from four Irish origin macroalgae

The efficiency of solid–liquid extraction (SLE) and pressurised liquid extraction (PLE) for the recovery of antioxidant and polyphenols from the Irish macroalgae, Fucus serratus, Laminaria digitata, Gracilaria gracilis and Codium fragile, was assessed using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays and the Folin–Ciocalteu total phenol content (TPC) assay. Fucus serratus had TPC and antioxidant activities thirty times higher than the other species. Solid–liquid extraction cold water (CW_SLE) had the highest TPC (81.17 μg GAE mg^?1 sample) derived from F. serratus, compared with the TPC of 61.12 μg GAE mg^?1 sample for the corresponding PLE extract. For both SLE and PLE extracts, low TPC levels were observed in L. digitata, G. gracilis and C. fragile. The majority of SLE extracts possessed higher FRAP and DPPH activities compared with their PLE counterparts. This study indicates that the high temperatures and pressures in PLE did not enhance the antioxidant activities relative to conventional SLE extraction.     

Effects of thermosonication and orange by‐products extracts on quality attributes of carrot (Daucus carota) juice during storage

Effect of thermosonication on carrot juice containing peel (CJPL) and pulp (CJPP) extracts from orange at different concentration (0.5, 2.0 and 4.0 mg GAE per g extracts) of total phenolic contents (TPC) was evaluated for quality attributes. Thermosonication of juice was done at 52 °C, 6 min for CJPL and 60 °C, 5 min for CJPP (values based on our preliminary optimisation results of ultrasound process conditions of the juice) at 40 kHz and 110W. Effect of thermosonication and addition of peel and pulp extracts at highest concentration increased the TPC and antioxidant activity of the juice (P < 0.05). Highest inactivation of microorganisms and better sensory attributes was achieved in thermosonicated CJPP for 21 days. Titratable acidity, pH, browning index and viscosity were improved by thermosonication and at highest extract concentration. °Brix and total carotenoid were not significantly affected by treatments. Therefore, thermosonication at 60 °C and 4.0 mg GAE per g extract concentration of peel and pulp may be used in formulation of functional carrot juice with improved health properties.     

A novel antioxidant source: evaluation of in vitro bioaccessibility,antioxidant activity and polyphenol profile of phenolic extract from black radish peel wastes (Raphanus sativus L. var. niger) during simulated gastrointestinal digestion

The aim of this study was to evaluate the potency of polyphenolic extract from black radish (Raphanus sativus L. var. niger) root peel waste (PEBRRP) as an antioxidant food additive. PEBRRP was found a powerful antioxidant extract, in which had 172.9 ± 11.5, 462.72 ± 3.05, and 796.51 ± 10.4 mg TE per g dw of total antioxidant capacity (TAC) by CUPRAC, DPPH, and FRAP assays, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of PEBRRP were found as 305.51 ± 5.2 mg GAE per g dw and 171.58 ± 6.2 mg CAE per g dw, respectively. The ferulic acid (28.02 ± 4.5 mg per g dw) and epicatechin (19.82 ± 3.6 mg per g dw) were identified as the main polyphenols in undigested PEBRRP. The bioaccessibility of total phenolic and total flavonoid compounds of PEBRRP was found approximately 5%, and the antioxidant capacity of bioaccessible PEBRPP fraction was determined 6% in CUPRAC, 36% in DPPH and 47% in FRAP methods.     

Comparative analysis of techno-functional properties,starch digestion and protein quality of pigmented chickpea flours

The aims of this investigation were to evaluate physicochemical, functional, pasting, and thermal properties, as well as the starch and protein digestibilities of whole flours obtained from ten chickpea cultivars differing in seed coat colour (black, brown, green, red and cream). The coloured chickpeas flours contained higher amounts of bioactive compounds as total phenolics (TPC, 241.25–444.41 μg gallic acid equivalents per g), β-glucans (1.02–2.42 g/100 g), resistant starch (22.68–37.52% of total starch) and higher protein digestibility corrected amino acid scores (PDCAAS, 0.61–0.82) compared with the cream-coloured chickpea Blanco Sinaloa (C.BS). The principal component analysis showed several differences among the chemical compositions, starch digestions and seed protein qualities; in the same sense we found a correlation between TPC and starch content with their thermal properties and starch digestion. Subsequently, pigmented chickpea cultivars have potential as functional ingredients for food product development.     

Antihypertensive properties of aqueous extracts of vegetable leaf‐fortified bread after oral administration to spontaneously hypertensive rats

This study investigated the potential cardiovascular health benefits of leavened bread produced from wheat flour that contained 1%, 2% and 3% additions of leafy vegetable powders obtained from Amaranthus viridis (AO), Solanum macrocarpon (SM) or Telfairia occidentalis (TO). Dried breads were extracted with water at 60 °C followed by analysis for total polyphenolic content (TPC), as well as in vitro inhibitions of angiotensin‐converting enzyme and renin activities. HPLC analysis of the bread extracts indicated the presence of mainly rutin, gallic acid, myricetin and caffeic acid. TPC of the vegetable‐fortified breads was significantly (P < 0.05) higher (5.8–7.6 mg gallic acid equivalent, GAE/g) than that of control bread (5.5 mg GAE/g). Oral administration of 100 mg dried extract/kg body weight to spontaneously hypertensive rats led to reductions (up to 42 mmHg) in systolic, diastolic and mean arterial blood pressure in comparison with 20 mmHg for the control bread.     

Edible foxtail millet flour stabilises and retain the in vitro activity of blueberry bioactive components

Blueberries, a functional food, are rich in bioactive polyphenols and anthocyanins. However, the shelf life is short and requires cold storage. This study provides evidence that edible foxtail millet flour (FMF) efficiently sorbs only blueberry bioactive components (polyphenols and anthocyanins) but not sugars, improves their stability and retains the activity. The concentration of blueberry polyphenols and anthocyanins sorbed to FMF ranged from 6 to 113 and 4 to 41 mg g^?1, respectively. The concentration of bioactive components in one serving of blueberries (73 g) is equivalent to those present in 1.2 g of blueberry‐enriched foxtail millet flour (BFMF). The blueberry bioactive sorbed onto FMF remained stable for at least 16 weeks at 40 °C. BFMF eluates inhibited α‐glucosidase enzyme activity and scavenged the free radicals conferring that blueberry bioactive components in BFMF retained the activity. The sorption process described here provides a practical way of creating low glycemic protein‐rich edible flour enriched with plant bioactive compounds without sugars.     

海棠果实多酚提取物对胃癌细胞BGC-803的体外抑制活性

以‘富士’苹果为对照,研究了4种海棠果实提取物的总多酚含量和对人胃癌细胞BGC-803的体外抑制活性。用福林-酚法测定总多酚含量,采用高效液相色谱法测定单体酚种类和含量,用细胞活力检测试剂盒和倒置显微镜检测对人胃癌细胞BGC-803的抑制作用。结果表明:5种果实提取物总多酚含量变化范围为405.99~4663.30 mg GAE/100 g,海棠果实提取物总多酚含量均高于‘富士’苹果;5种果实多酚提取物对人胃癌细胞BGC-803的抑制作用(IC₅₀值)比较结果显示,红果肉的‘亚当’海棠(42.29 μg/mL)和‘红丽’海棠(64.67 μg/mL)优于黄果肉的‘海红果’海棠(1466 μg/mL)和西府海棠(2291 μg/mL),4种海棠均优于‘富士’苹果(3476 μg/mL);5种果实多酚提取物中单体酚主要有原花青素B₁、原花青素B₂、儿茶素、表儿茶素等;两种红果肉海棠(‘亚当’海棠、‘红丽’海棠)中,以矢车菊素半乳糖苷和低聚原花青素类为主的多酚类物质含量高于黄果肉的‘海红果’海棠、西府海棠和‘富士’苹果。     

Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting

The bioactive composition of coffee, as one of the most popular beverages in the world, has attracted interest as a potential source of beneficial bioactive compounds, especially polyphenols and caffeine. Since the content of these compounds is affected by the processing conditions, the objective of this study was to determine the content of polyphenolic compounds and caffeine in four different coffee varieties: Minas and Cioccolatato (Coffea arabica), and Cherry and Vietnam (Coffea canephora syn. Coffea robusta), roasted by three varying degrees (light, medium and dark). The content of the polyphenolic compounds and the antioxidant capacity of coffees were determined using UV/Vis spectrophotometric methods, while the content of chlorogenic acid derivatives was determined using HPLC analysis. The caffeine content was determined by means of two spectrophotometric methods, as well as HPLC analysis. Additionally, raw caffeine was also obtained by an isolation procedure with chloroform. Cherry coffee, a variety of C. canephora exhibited the highest overall content of total phenols (42.37 mg GAE/g), followed by Minas coffee, while Cioccolatato contained the lowest TPC (33.12 mg GAE/g). Cherry coffee also exhibited the highest content of individual classes of polyphenols (flavan-3-ols, procyanidins and tannins), while the highest content of chlorogenic acid (CQA) derivatives was determined in Minas and Cioccolatato coffees (C. arabica). The highest content of total and individual polyphenolic compounds was determined in coffees roasted in both light and medium roasting conditions, which was also observed for the content of CQA derivatives and antioxidant capacity of roasted coffees. The highest caffeine content in the coffee samples was determined by employing the HPLC analysis (0.06–2.55%). Light roasted Cherry coffee contained the highest overall content of caffeine among all coffees, which exhibited a decrease with intensified roasting.     

Changes in bioactive compounds and antioxidant capacity of fresh-cut cashew apple

In this study, ascorbic acid, total polyphenols and proanthocyanidins of fresh-cut cashew apple were quantified. Antioxidant capacity was determined in whole juice and in polyphenols extracts by three methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and ??-carotene bleaching. Effect of cutting and storage for 24 h at 2 °C, 27 °C and 40 °C on these compounds were also evaluated. Cashew apple presented 163 mg of ascorbic acid per 100 g of fresh weight (FW). Soluble and hydrolysable polyphenols contents were 12.79 mg GAE/100 g FW and 18.53 mg GAE/100 g FW and proanthocyanidins were 9.27 mg/100 g FW. Antioxidant capacity of juice and polyphenols extract was high for DPPH method. Storage temperatures affected bioactive compounds on cut cashew apple. The content of ascorbic acid decreased in all temperatures. Proanthocyanidins were more sensitive to 40 °C than to other temperatures. The content of polyphenols and antioxidant capacity of juice by DPPH assay did not change. However, the reducing power was lower in samples kept at high temperatures. A strong positive correlation between ascorbic acid and FRAP (r = 0.99) and a negative correlation between DPPH and FRAP (r = − 0.79) were observed. No correlations were found between polyphenols and antioxidant capacity indicating the importance of phenolic composition in the extracts. The results confirm the importance of temperature and injury on the quality of cashew apple.     

Effect of different drying methods and storage time on the retention of bioactive compounds and antibacterial activity of wine grape pomace (pinot noir and merlot)

The effects of different drying methods (40 °C conventional and vacuum oven, 25 °C ambient air and freeze dry) on the stability of two red wine grape (Pinot Noir, PN and Merlot, M) byproducts, pomace containing skins and seeds (P) and pomace containing skins only (S) were investigated. Freeze dried samples retained the highest bioactive compounds with total phenolic content (TPC) of 21.19-67.74 mg GAE/g d.m., anthocyanin content (ACY) of 0.35-0.76 mg Mal-3-glu/g d.m., DPPH antiradical scavenge activity (ARS) of 22.01-37.46 mg AAE/g d.m., and total flavanol content (TFC) of 30.16-106.61 mg CE/g d.m., followed with ambient air dried samples. All samples lost significant amount of bioactive compounds during 16 wk of storage at 15 ± 2 °C, in which ambient air and freeze dried samples had TPC reduction of 32-56% and 35-58%, respectively, but ARS in PN-P and M-P still remained more than 50 mg TE/g d.m. Overall, TPC, ARS, and TFC were higher in PN than in M, and higher in pomace than in skins, while reverse results were observed in ACY. Pomace extracts showed higher antibacterial efficiency against Listeria innocua ATCC 51142 than Escherichia coli ATCC 25922 with minimal inhibition concentration (MIC) of 3%, 6%, 4%, and 9% against E. coli, and 2%, 7%, 3%, and 8% against L. innocua for PN-P, PN-S, M-P, and M-S samples, respectively. Dietary fiber content of samples was 57-63% of total dry matter. This study demonstrated that Pinot Noir and Merlot pomace are good sources of antioxidant dietary fibers and may be incorporated into various food products as a functional ingredient. Practical Application: Wine grape pomace (WGP), the byproduct of wine making, is a good source of polyphenols and dietary fibers and may be incorporated into various food products as a functional ingredient. This study reported the effect of four drying methods and storage at 15 ± 2 °C up to 4 months on the retention of polyphenols and antioxidant activity in two types of red WGP (with and without seeds). Antibacterial activity, dietary fiber content and the basic physicochemical properties of dried pomace powder were also reported. The information is essential for developing specific applications of the pomace.