Separation and characterization of cis-trans isomers of α-tocotrienol by HPLC using a permethylated β-cyclodextrin phase

 The behaviour of α-, β-, γ- and δ-tocotrienols (structurally related to tocopherols with naturally trans-configurated double bonds in the side-chain) during HPLC on a permethylated β-cyclodextrin phase was studied. A newly developed isocratic HPLC method is described with an acetonitrile/water (58:42 by vol.) eluent and fluorescence detection at an emission wavelength of 330 nm (excitation wavelength = 295 nm). Each of the separately injected tocotrienols exhibited four peaks. The four separated components of α-tocotrienol were identified by spectroscopy (MS, ¹H-NMR, FTIR) to be structural side-chain isomers. The order of retention times was determined to be all-cis-α-tocotrienol followed by cis-trans-/trans-cis-α-tocotrienol (differentiation between the two compounds was not possible) with all-trans-α-tocotrienol as the last eluting isomer. Received: 27 June 1997     

Antihyperglycemic activity of polyphenolic components of black/bitter cumin <Emphasis Type="Italic">Centratherum anthelminticum</Emphasis> (L.) Kuntze seeds

The effect of black/bitter cumin seeds Centratherum anthelminticum (L.) Kuntze extract (CA) containing mixture of polyphenolic compounds was tested on rat intestinal α-glucosidases, human salivary α-amylase activity and postprandial hyperglycemia in rats. Polyphenolic components of C. anthelminticum seeds (CA) dose dependently inhibited rat intestinal disaccharidases. IC₅₀ values were found to be 34.1 ± 3.8, 62.2 ± 4.5 and 500.5 ± 11.9 μg of CA for rat intestinal sucrase, maltase and p-nitrophenyl α-d-glucopyranoside (PNP-glycoside), respectively. CA also inhibited human salivary α-amylase activity with IC₅₀ value of 185.5 ± 4.9 μg. The inhibitory effect of CA was found to be 8–32 fold more potent than dl-catechin but less effective than acarbose on rat intestinal disaccharidases and salivary α-amylase. The enzyme kinetic studies showed a non-competitive type of inhibition with a low K _i value of 30.24 μg, 76.67 μg and 341.60 μg of CA for maltase, sucrase and PNP-glycoside hydrolysis activities, respectively. The in vitro inhibition of glucosidases was further confirmed by in vivo maltose tolerance test in rats. Feeding of CA at 50–200 mg/kg body weight (b.wt) to maltose (2.0 g/kg b.wt), loaded rats significantly reduced the postprandial plasma glucose levels compared with acarbose. The inhibitory components of CA were identified as a mixture of polyphenolic compounds viz., gallic acid, protocatechuic acid, caffeic acid, ellagic acid, ferulic acid, quercetin and kaempferol. This study demonstrated that CA exerts antihyperglycemic effect by decreasing postprandial glucose in rats by modulating α- amylase and glucosidases (sucrase and maltase) activity and thus may be useful for the management of diabetes mellitus.     

Freshwater fish as a dietary source of vitamin A in Cambodia

Vitamin A deficiency is a public health problem among children and women. Common Cambodian fish species were sampled and screened for vitamin A content. Contents of vitamin A-active compounds (all-trans retinol, all-trans dehydroretinol, 13-cis retinol, 13-cis dehydroretinol and β-carotene) were determined by high-performance liquid chromatography in samples of raw, whole fish from 29 fish species and in raw, edible parts from 24 species. Replicate samples were analysed in seven selected species. Two species, Parachela siamensis and Rasbora tornieri had very high vitamin A contents >1500 RAE/100 g raw, whole fish, and six species (Barbodes altus, Barbodes gonionatus, Dermogenys pusilla, Puntioplites proctozysron and Thynnichthys thynnoides) had high contents of 500–1500 RAE/100 g raw, whole fish. Two species, Puntioplites proctozysron and Thynnichthys thynnoides had high vitamin A contents in raw, edible parts, after employing traditional cleaning practices. (RAE: The amount of vitamin A active compounds in food is expressed as retinol activity equivalents (RAE), defined as the bioefficacy relative to all-trans-retinol [ West, C. E., & Eilander, A. (2002). Consequences of revised estimates of carotenoid bioefficacy for the control of vitamin A deficiency in developing countries. Journal of Nutrition, 132, 2920S–2926S]. Dehydroretinoids (vitamin A₂) are not converted to all-trans-retinol but have similar metabolic functions. In this paper, RAE refers to the functional bioefficacy as defined by Brouwer et al. [ Brouwer, I. A., Dusseldorp, M. V., West, C. E., & Steegers-Theunissen, R. P. M. (2001). Bioavailability and bioefficacy of folate and folic acid in man. Nutrition Research Review, 14, 267–293]).     

Effect of dietary levels of fat, α-tocopherol and astaxanthin on colour and lipid oxidation during storage of frozen rainbow trout (Oncorhynchus mykiss) and during chill storage of smoked trout

 Female rainbow trout (Oncorhynchus mykiss) with an initial weight of 0.8–0.9 kg were raised in two experiments including a total of 2550 fish divided into 17 groups. The fish were raised for 6 months on 13 different feeds (four fish groups were replicates) varying in dietary levels of fat (27% or 32%), astaxanthin (40, 70 or 100 mg astaxanthin/kg feed) and vitamin E (α-tocopherol; 100, 300 or 600 mg all-rac-α-tocopheryl acetate/kg feed). The levels of fat, astaxanthin and α-tocopherol in the fillets all increased with increasing dietary levels of each feed component. Furthermore, astaxanthin deposition was found to be significantly improved by increasing the dietary fat level from 27% to 32%, but was not affected by dietary levels of α-tocopherol. The highest deposition of α-tocopherol was found in fish fed the lowest level of astaxanthin (40 mg/kg), whereas α-tocopherol deposition was unaffected by the dietary fat level. Frozen storage (–28  °C) of gutted, cleaned and glazed raw fish for 18 months significantly reduced astaxanthin and α-tocopherol levels, while lipid oxidation, measured as thiobarbituric acid reactive substances (TBARS) was limited. In the first experiment, the highest TBARS levels were found during frozen storage in fish fed the lowest level of astaxanthin (40 mg/kg versus 70 mg/kg or 100 mg/kg); unaffected by dietary levels of α-tocopherol (100 mg/kg versus 600 mg/kg), whereas the dietary astaxanthin level (70 mg/kg versus 100 mg/kg) did not influence lipid oxidation in frozen fish in the second experiment. After brine injection, fillets of fish were smoked and a vacuum-packed (95%), sliced product in a transparent laminate was produced. The quality (pigmentation and lipid oxidation) during 3 weeks of illuminated, chill storage (3  °C) was compared for smoked products produced from fresh fish and from fish stored at –28  °C for 12 months and 18 months. Smoked fillets from fish fed 32% fat were found to be less red than those from fish fed 27% fat, and the astaxanthin content and surface redness of the smoked product decreased during chill storage. Lipid oxidation was pronounced in smoked trout, but a high level of α-tocopherol in the fillet significantly reduced lipid oxidation during chill storage of the smoked product. Lipid oxidation in smoked fillets from fish fed 32% fat was more pronounced than in fish fed 27% fat, but increasing the dietary α-tocopherol level from 300 mg/kg feed to 600 mg/kg feed effectively counteracted the negative effect of the high-fat diet on lipid oxidation in the smoked product. Astaxanthin did not affect lipid oxidation in the chill-stored smoked product, in contrast to the frozen, raw fish. Astaxanthin seems to protect against the very early stages of lipid oxidation, while α-tocopherol is more important as an antioxidant at more advanced stages of lipid oxidation. Received: 8 January 1998 / Revised version: 23 March 1998     

Is there a direct relationship between oral astringency and human salivary protein binding?

For decades, it is believed that astringency is due to the polyphenol-induced complexation of proline-rich salivary proteins in the oral cavity. In order to compare for the first time the human sensory threshold concentrations and the salivary protein binding activity of a series of astringent stimuli, human saliva protein was incubated for 5 min at 37 °C in the presence of astringent food-derived compounds and, after micro-centrifugation, the amount of the target molecules in the supernatant was quantitatively determined by HPLC-UV/Vis. Significant protein binding was observed for (−)-epigallocatechin-3-gallate, (−)-gallocatechin-3-gallate, (+)-gallocatechin, and (−)-catechin-3-gallate, all of which containing at least one galloyl moiety in the molecule and exhibiting rather high sensory thresholds of more than 200 μmol/L. In comparison, (+)-catechin and procyanidin B2, both lacking in any galloyl function, showed only comparatively low binding activity and, most interestingly, quercetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside and 3-carboxymethyl-indole-1-N-β-d-glucopyranoside did not show any protein binding at all, although the later N- and O-glycosides exhibited extraordinarily low sensory threshold concentrations of less than 0.001 and 0.0003 μmol/L, respectively. The data give some first evidence that the quantity of the non-bound, “free” astringent stimulus in the saliva liquid might be more closely related to the sensory perception of astringency than the amount complexed or precipitated by proteins. It is therefore questionable as to whether oral perception of astringency is related to the complexation and/or precipitation of salivary proteins.     

Rapid Determination of α-Tocopherol in Vegetable Oils by Fourier Transform Infrared Spectroscopy

The aim of this study was to develop a rapid methodology for the analysis of α-tocopherol in vegetable oils as an alternative to the high-performance liquid chromatography (HPLC) methods: Fourier transform infrared (FT-IR) methodology. Thirteen vegetable oils (corn, peanut, soybean, sunflower and mixtures) commercially obtained were analysed by reverse-phase HPLC with fluorescence detection (FD) in order to obtain standard values for α-tocopherol. Validation tests were performed concerning the HPLC method. The HPLC method is valid for α-tocopherol analysis in the 1–90 mg/L linear range. Method repeatability was 3.6%, and accuracy results were within 70–95%. FT-IR spectra of the vegetable oils were acquired in the attenuated total reflection mode (45° and 60° crystals of ZnSe). To predict the α-tocopherol content in samples, calibration models were designed, and the partial least squares method was used to analyse data from FT-IR spectral region at 1,472–1,078 cm⁻¹. Results obtained showed that the calibration model implemented with a 45° crystal is more suitable for the proposed analysis. Five extra samples of vegetable oils were analysed by HPLC/FD and by FT-IR. Using the calibration model implemented for FT-IR (45° crystal), the α-tocopherol content in samples was determined. The results obtained by HPLC/FD and FT-IR were compared, and there were no significant differences among them. Results showed that FT-IR can be used as an alternative method for rapid screening of α-tocopherol in vegetable oils without sample pre-treatment. Presented in part at the “AOAC Europe section international workshop: Enforcement of European Legislation on Food and Water: Analytical and Toxicological Aspects,” in Lisbon, April 2008, and published in abstract form.     

Flavonoid glycosides from cowpea seeds (Vigna sinensis K.) inhibit LDL oxidation

Six flavonoid glycosides were isolated from the n-butanol fraction of cowpea seeds (Vigna sinensis K.) through silica gel (SiO₂) and octadecyl silica gel (ODS) column chromatographies. Based on their chemical structures determined via interpretation of spectroscopic data including NMR, MS, and IR, the compounds were identified as kaempferol 3-O-β-d-sophoroside (1), quercetin 3-O-β-d-sophoroside (2), isoquercitrin (3), hyperin (4), catechin 7-O-β-d-glucopyranoside (5), and quercetin 3-O-β-Dglucopyranosyl( 1→6)-O-β-d-galactopyranoside (6). This is the first report of the isolation of these flavonoids from this plant. Among these flavonoids, compound 2, 5, and 6 significantly inhibited LDL oxidation exhibiting 96.0±0.1 (IC₅₀: 3.9 μM), 96.8±1.7 (IC₅₀: 2.9 μM), and 97.4±0.1% (IC₅₀: 3.5 μM) inhibition, respectively, at a concentration of 40 μM.     

Purification and application of α-galactosidase from germinating coffee beans (<Emphasis Type="Italic">Coffea arabica</Emphasis>)

The objective of this study was to prepare and purify α-galactosidase (α-Gal) from germinating coffee beans. The molecular weight of purified α-Gal from germinating coffee beans was determined to be 38.8 kDa by SDS-PAGE. Then the purified α-Gal was applied to synthesize galactosyl β-cyclodextrin using melibiose as donor and β-cyclodextrin as acceptor. Galactosyl β-cyclodextrin was isolated by preparative high-performance liquid chromatography (HPLC) and its structure was analyzed and elucidated by HPLC, fourier transform infrared spectrometer, electro spraying ionization-mass spectrometry, and ¹³C nuclear magnetic resonance. Our results strongly demonstrate that the synthesized product is a mono-6-O-α-d-galactopyranosyl-β-cyclodextrin and the purified α-galactosidase could transfer one galactosyl residue directly to the β-cyclodextrin ring and synthesize the mono-6-O-α-d-galactosyl β-cyclodextrin.     

Aqueous medium enzymatic preparation of <Emphasis Type="SmallCaps">l</Emphasis>-alpha glycerylphosphorylcholine optimized by response surface methodology

The ability of Rhizopus chinensis lipase (Thermo 4S-3) to catalyze the deacylation of l,2-diacyl-sn-glycero-3-phosphocholines (sn-1,2-PC) for l-alpha glycerylphosphorylcholine (l-α-GPC) preparation was investigated. Response surface methodology (RSM), based on a modified central composite rotatable design, was employed to examine the effects of substrate concentrations, temperature, enzyme loading, and dosage of CaCl₂ on the l-α-GPC yield. RSM analysis indicated good correlation between experimental and predicated values. The optimal condition was confirmed as follows: reaction time, 3.5 h; temperature, 43 °C; enzyme loading, 28.2 U mL⁻¹; substrate concentration, 51.5 mg mL⁻¹; and dosage of CaCl₂, 1.9 mg mL⁻¹. Under these conditions, the l-α-GPC yield increased by 96.8%, which was close to the amount predicted by the model.     

Antioxidant activity of lignans from fringe tree (Chionanthus virginicus L.)

Fringe tree (Chionanthus virginicus L.), a shrub of the eastern part of America, used as a raw material by pharmaceutical industries for cholagoque, diuretic, tonic and the preparation of homeopathic tinctures. The identification of lignans as major antioxidant components and determination of their antioxidant activities are of considerable interest, because of the role they play in pharmacological actions. The potential antioxidant activity of the lignans such as phillyrin, pinoresinol-β-d-glucoside (PDG) and pinoresinol di-β-d-glucoside (PDDG) from root bark of fringe tree (C. virginicus L.) were examined by different antioxidant tests including; 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH^•) scavenging, superoxide anion radical (O₂ ^•-) scavenging, total antioxidant activity by ferric thiocyanate method, reducing activity by Fe³⁺–Fe²⁺ transformation, hydrogen peroxide (H₂O₂) scavenging and ferrous metal (Fe⁺²) chelating activities. Phillyrin, PDG and PDDG, as antioxidants, neutralized the activities of radicals and inhibited the peroxidation reactions of linoleic acid emulsion. The total antioxidant activity was determined according to the ferric thiocyanate method. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and trolox, which is a water-soluble analogue of tocopherol, were used as the reference antioxidant compounds. Phillyrin, PDG and PDDG showed 67.6, 77.3 and 64.2% inhibition on lipid peroxidation of linoleic acid emulsion, respectively, at the concentration of 20 μg/mL. On the other hand, BHA, BHT, α-tocopherol and trolox exhibited 74.4, 71.2, 54.7 and 20.6% inhibition on peroxidation of linoleic acid emulsion, respectively, at the above mentioned concentration. In addition, phillyrin, PDG and PDDG were effective on DPPH^•, ABTS^•+ and O₂ ^•- scavenging, H₂O₂ scavenging, total reducing power and metal chelating effect on ferrous ions activities. Also, BHA, BHT, α-tocopherol and trolox were used as references antioxidants for these various antioxidant activities.     

In vitro evaluation of the antioxidant activities in the differentially processed seeds from underutilized legume, Bauhinia vahlii Wight & Arn

Antioxidant potential and total phenolics content of 70% acetone extracts of the raw and processed seeds of Bauhinia vahlii were evaluated. The extract of raw seeds contained higher levels of total phenolics (30.8 g/100 g) and tannins (19.6 g/100 g) compared to dry heated and soaking followed by autoclaving seed extracts. Extracts were screened for antioxidant and free radical scavenging activities using various chemical and in vitro model systems. In all the models, except DPPH radical scavenging activity, the extract from raw seeds manifested the strongest antioxidant activity than that from processed seeds. In β-carotene/linoleic acid emulsion system and superoxide scavenging activity, the raw seed extract registered more activity when compared to the standards (butylated hydroxyanisole and α-tocopherol). Whereas, the extract from dry heated seed exhibited higher DPPH^· scavenging activity (IC₅₀ 70.77 μg/mL) than the raw seeds (IC₅₀ 74.4 μg/mL). This study has to some extent validated the antioxidant potential of the seeds of B. vahlii.     

Isolation and identification of Di-D-fructose dianhydrides resulting from heat-induced degradation of inulin

Dry heating of inulin up to 200 °C for 30 min resulted in a wide range of degradation products, from which five quantitatively dominating compounds were isolated using flash chromatography and semi-preparative HPLC–RI. It was possible to identify four different DFDAs (di-d-fructose dianhydrides) by means of one- and two-dimensional NMR, namely DFA III (α-D-Fruf-1,2′:2,3′-β-D-Fruf), DFA I (α-D-Fruf-1,2′;2,1′-β-D-Fruf), DFA VII (α-D-Fruf-1,2′;2,1′-α-D-Fruf), and β-D-Fruf-1,2′;2,1′-β-D-Fruf. For the fifth compound, the structure of the difructan α-D-Fruf-1,2′-β-D-Fruf was proposed. Using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC–PAD), it was possible to quantify those isolated DFDAs in inulin caramels to a total amount of up to 25%, indicating that dry heating of inulin may be a suitable tool to enrich caramels with DFDAs.     

Mango peel fibres with antioxidant activity

 Antioxidant compounds associated with some types of dietary fibres may be responsible in part for the beneficial effects on health of high-dietary-fibre diets. The antioxidant activity of a high-dietary-fibre mango peel product and of some commercial samples was determined by the ferric thiocyanate colorimetric method. At a concentration of 0.05%, the antioxidant activity of mango peel dietary fibre was 0.75 times as effective as that of 2-tert-butyl-4-hydroxyanisol (BHA) and 1.4 and 3.4 times higher, respectively, than that of French PARAD’OX (a commercial polyphenols concentrate) and of DL-α-tocopherol. All Bran, Quaker Oats, lemon and apple fibre did not exhibit any antioxidant capacity. The obtention of high-dietary-fibre products with bioactive compounds could be useful for the food industry and the antioxidant activity may be a new property to consider in the quality evaluation of these ingredients. Received: 25 January 1996 / Revised version: 10 June 1996     

Mango peel fibres with antioxidant activity

 Antioxidant compounds associated with some types of dietary fibres may be responsible in part for the beneficial effects on health of high-dietary-fibre diets. The antioxidant activity of a high-dietary-fibre mango peel product and of some commercial samples was determined by the ferric thiocyanate colorimetric method. At a concentration of 0.05%, the antioxidant activity of mango peel dietary fibre was 0.75 times as effective as that of 2-tert-butyl-4-hydroxyanisol (BHA) and 1.4 and 3.4 times higher, respectively, than that of French PARAD’OX (a commercial polyphenols concentrate) and of DL-α-tocopherol. All Bran, Quaker Oats, lemon and apple fibre did not exhibit any antioxidant capacity. The obtention of high-dietary-fibre products with bioactive compounds could be useful for the food industry and the antioxidant activity may be a new property to consider in the quality evaluation of these ingredients. Received: 25 January 1996 / Revised version: 10 June 1996     

Application of DPPH absorbance method to monitor the degree of oxidation in thermally-oxidized oil model system with antioxidants

Changes of 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorbance were monitored in thermally-oxidized lard containing free radical scavengers (FRSs). Hydrogen donating abilities of α-tocopherol to DPPH were higher than those of sesamol and butylated hydroxyanisole (BHA), indicating reactivity of DPPH and FRSs in lard depends on the types of FRSs. For the first 20 min oxidation, DPPH absorbance from lard with 3.38 μmol/g α-tocopherol, sesamol, and BHA increased by 0.324, 0.240, and 0.313, respectively while those from lard without FRS decreased by 0.350. Results of conjugated dienoic acid (CDA), and p-anisidine value (p-AV) showed that antioxidative activity were high in the order of sesamol, BHA, and α-tocopherol, which implies that hydrogen donating abilites of FRSs may not be the most critical factor to determine antioxidant effectiveness. Monitoring DPPH absorbance in oxidized lard with FRS could be useful indicators for comparing antioxidative ability of FRSs.     

Highly efficient preparation of free all-trans-astaxanthin from Haematococcus pluvialis extract by a rapid biocatalytic method based on crude extracellular enzyme extract

A highly efficient, rapid, green and safe procedure for the preparation of free all-trans-astaxanthin from Haematococcus pluvialis algal extract, by a crude extracellular enzyme extract, was reported. The free all-trans-astaxanthin obtained by the biocatalysed method had fewer side products compared to the saponification procedure. Through single-factor experiments and a Box–Behnken design, it was possible to find the optimal biocatalytic conditions for the hydrolysis of 2 mg of H. pluvialis oil with 14.7 mg (protein content) of lyophilised crude extracellular enzyme extract obtained from Pseudomonas aeruginosa. The reaction was carried out in 30 min at pH 9.16 and 36 °C, in 5.5 mL total reaction volume, under nitrogen atmosphere and dark conditions. The hydrolysis ratio of the astaxanthin esters was 98.72%, and the production of free all-trans-astaxanthin was 82.83 μg per mg of H. pluvialis oil. The method herein reported was simpler than other enzymatic methods previously described and allowed saving of time and costs.     

Antioxidant activity of the differentially processed seeds of Jack bean (<Emphasis Type="Italic">Canavalia ensiformis</Emphasis> L. DC)

Antioxidant activity of 70% acetone extracts of raw and processed seeds of Jack bean (Canavalia ensiformis L. DC) was evaluated by various in vitro antioxidant assays, including total antioxidant, free radical scavenging, reducing power, metal ion chelating, β-carotene/linoleic acid bleaching, and antihemolytic activities. The total phenolics and tannin contents were higher in the extract of seeds processed by autoclaving with 1% ash solution (3.2 and 1.6 g/100 g extract, respectively). In general, all the extracts of processed seeds exhibited higher activity in various antioxidant systems, when compared to raw seeds but significant differences were noticed between processing methods. The extract of seeds autoclaved with 1% sugar solution showed higher DPPH radical scavenging activity (IC₅₀ 10.6 mg/mL). Interestingly, the extract of dry heated seeds registered higher inhibition of hemolysis (76.1%) compared to standards butylated hydroxyanisole (BHA) (66.2%) and α-tocopherol (59.3%) at the concentration of 500 μg/mL.     

Production of Cell Membrane-Bound α- and β-Glucosidase by Lactobacillus acidophilus

Hydrolytic enzymes, viz. α- and β-glucosidase, were produced from indigenous isolate, Lactobacillus acidophilus, isolated from fermented Eleusine coracana. Production of these enzymes was enhanced by optimizing media using one factor at a time followed by response surface methodology. The optimized media resulted in a 2.5- and 2.1-fold increase in α- and β-glucosidase production compared with their production in basal MRS medium. Localization studies indicated 80% of the total activity to be present in the cell membrane-bound fraction. Lack of sufficient release of these enzymes using various physical, chemical, and enzymatic methods confirmed their unique characteristic of being tightly cell membrane bound. Enzyme characterization revealed that both α- and β-glucosidase exhibited optimum catalytic activity at 50 °C and pH 6.0 and 5.0, respectively. K _m and V _max of α-glucosidase were 4.31 mM and 149 μmol min⁻¹ mL⁻¹ for p-nitrophenyl-α-d-glucopyranoside as substrate and 3.8 mM and 120 μmol min⁻¹ mL⁻¹ for β-glucosidase using p-nitrophenyl-β-d-glucopyranoside as the substrate.     

Extraction of Bioactive Compounds from Milled Grape Canes (Vitis vinifera) Using a Pressurized Low-Polarity Water Extractor

Trans-resveratrol and trans-ε-viniferin were extracted from milled grape canes using pressurized low-polarity water. The effects of temperature were significant for both compounds (p ≤ 0.05): extraction at 160 °C resulted in a 40% loss of trans-resveratrol compared to 95 °C while reduction of trans-ε-viniferin at both temperatures remained at 30%. Increasing ethanol concentration from 0% to 25% increased the extraction of total phenolics and trans-ε-viniferin by 44% and 489%, respectively. Solvent flow rate also influenced trans-ε-viniferin extraction. Antioxidant activity showed a strong correlation with total phenolic content of the extracts, and the two target phenolic compounds. Except for the modifier concentration, the extraction parameters studied were not statistically significant with respect to the antioxidant activity of extracts (p > 0.05). Effective diffusivities of trans-resveratrol multiplied from 3.3 × 10⁻¹¹ to 10.4 × 10⁻¹¹ m²/s by three times with increasing temperature. The modified Gompertz equation satisfactorily explained the extraction of the stilbenes investigated.