纤维素酶和果胶酶对番茄红素提取的影响

以番茄组织为材料,用含体积分数2%二氯甲烷的石油醚为提取溶剂,研究添加果胶酶和纤维素酶提取番茄红素的实验。结果表明,果胶酶和纤维素酶混合使用比单一酶的提取效率高,且果胶酶的提取效果比纤维素酶要好。在果胶酶和纤维素酶混合质量比为2:1时,提取番茄红素的最佳条件为A3B2C2D4,即混合酶用量0.6g/100g、酶解温度35℃、pH5.0、酶解时间5h,然后2%二氯甲烷的石油醚提取20min,4000r/min离心10min。因此,添加果胶酶和纤维素酶,用2%二氯甲烷的石油醚提取,可以提高番茄红素的提取率。     

番茄红素的酶法辅助提取研究

番茄红素是番茄中主要的类胡萝卜素,近年来的研究表明它具有防癌抗癌,延缓衰老等多种保健功能,是一种很有前景的功能性添加剂。本文研究的目的是为了得到酶提取的最佳工艺条件,考察了果胶酶和纤维素酶的用量和提取时间的影响,并和从番茄皮中的提取进行了比较,结果表明在番茄中的提取率分别增加了160%和120%,在番茄果皮提取中分别增加663%和650%。     

Optimisation of novel method for the extraction of steviosides from Stevia rebaudiana leaves

Stevioside, a diterpene glycoside, is well known for its intense sweetness and is used as a non-caloric sweetener. Its potential widespread use requires an easy and effective extraction method. Enzymatic extraction of stevioside from Stevia rebaudiana leaves with cellulase, pectinase and hemicellulase, using various parameters, such as concentration of enzyme, incubation time and temperature, was optimised. Hemicellulase was observed to give the highest stevioside yield (369.23 ± 0.11 μg) in 1 h in comparison to cellulase (359 ± 0.30 μg) and pectinases (333 ± 0.55 μg). Extraction from leaves under optimised conditions showed a remarkable increase in the yield (35 times) compared with a control experiment. The extraction conditions were further optimised using response surface methodology (RSM). A central composite design (CCD) was used for experimental design and analysis of the results to obtain optimal extraction conditions. Based on RSM analysis, temperature of 51-54 °C, time of 36-45 min and the cocktail of pectinase, cellulase and hemicellulase, set at 2% each, gave the best results. Under the optimised conditions, the experimental values were in close agreement with the prediction model and resulted in a three times yield enhancement of stevioside. The isolated stevioside was characterised through ¹H-NMR spectroscopy, by comparison with a stevioside standard.     

Lycopene extraction from tomato processing waste using ultrasound and cell-wall degrading enzymes

The tomato processing wastes are rich in lycopene pigment, which can be consumed as a natural food colorant and bioactive ingredient. The present study investigates the appropriateness of ultrasound pretreatment and enzymatic treatment with cellulase and pectinase enzymes to extract lycopene pigment from tomato processing wastes using response surface methodology (RSM). To achieve this goal, a central composite design consisting of four independent variables including cellulase concentration (0–10%), pectinase concentration (0–5%), ultrasonic time (0–60 min) and pH (3.5–5.5) was used to examine the influences of these process variables on the lycopene extraction. The second order model of lycopene extraction obtained from RSM analysis had the p value less than 0.001 and represented a coefficient of determination (R²) of 93.82%. Thus, a satisfactorily agreement between experimental and predicted values for lycopene content obtained by the second order model was observed. In addition, the Fourier Transform Infrared spectroscopy results did not show any destruction of functional groups of the investigated extracts containing lycopene pigment. Scanning electronic microscopy images from the remaining tomato processing wastes after treatment with more lycopene content extraction demonstrated more porous structure. These results implied that ultrasound-assisted enzymatic extraction was an efficient extracting method.     

Effects of electroplasmolysis treatment on chlorophyll and carotenoid extraction yield from spinach and tomato

In this study, the effects of electroplasmolysis on β-carotene, chlorophyll-a, chlorophyll-b and total chlorophyll contents of spinach extract and β-carotene and lycopene contents of tomatoes extracts were investigated. Three different voltage gradients (40, 60, 80 V/cm) and three different application periods (4, 8, 12 s) were used. The effects of water bath heating at different temperatures on the extraction yield of colorants were also studied. After pre-treatments, β-carotene, lycopene, chlorophyll-a, and chlorophyll-b extraction was performed. Total solid content, pH and titratable acidity of the spinach and tomato samples were also determined.In spinach, the highest extraction yield efficiency for β-carotene (19.7%) was obtained by water bath heating. The extraction yield efficiencies for chlorophyll-a, chlorophyll-b and total chlorophyll were 14.9%, 12.6% and 13.7% respectively, by the electroplasmolysis treatment at 60 V/cm for 8 s. In tomato, the highest increase in extraction yield efficiencies of β-carotene (139.1%) and lycopene (112.4%) was obtained by electroplasmolysis treatment at 80 V/cm for 4 s.     

Process optimisation for recovery of carotenoids from tomato waste

Carotenoids constitute an important component of waste originating from tomato processing plants. Studies were carried out to assess the extraction yield of tomato waste carotenoids in different solvents and solvent mixtures and to optimise the extraction conditions for maximum recovery. A mixture of ethyl acetate and hexane gave the highest carotenoid extraction yield among the others examined. Extraction conditions, such as percentage of hexane in the solvent mixture of ethyl acetate and hexane, ratio of solvent to waste and particle size were optimised using a statistically designed experiment. A regression equation for predicting the carotenoid yield as a function of three extraction variables was derived by statistical analysis and a model with predictive ability of 0.97 was obtained. The optimised conditions for maximum carotenoid yield (37.5 mg kg⁻¹ dry waste) were 45% hexane in solvent mixture, solvent mixture to waste ratio of 9.1:1 (v/w) and particle size 0.56 mm.     

Enzyme assisted extraction of luteolin and apigenin from pigeonpea [Cajanuscajan (L.) Millsp.] leaves

Luteolin and apigenin are naturally occurring flavones with a wide spectrum of pharmacological properties. In the present study, enzyme assisted extraction of luteolin and apigenin from pigeonpea leaves using commercial plant cell wall degrading enzyme preparations including cellulase, beta-glucosidase and pectinase were examined. We found that pectinase offered a better performance in enhancement of the extraction yields of luteolin and apigenin than cellulase and beta-glucosidase. The pectinase assisted extraction process was further optimized by varying different parameters such as pectinase concentration, time of incubation, pH of pectinase solution, and incubation temperature. The optimum parameters were obtained as follows: 0.4 mg/ml pectinase, incubation for 18 h at 30–35 °C, pH of pectinase solution 3.5–4. Under the optimum conditions, the extraction yields of luteolin and apigenin achieved 0.268 and 0.132 mg/g in pectinase treated sample, which increased 248% and 239%, respectively, compared with the untreated ones.     

Lycopene-rich fractions derived from pink guava by-product and their potential activity towards hydrogen peroxide-induced cellular and DNA damage

Effects of solvent and supercritical carbon dioxide (SC-CO₂) extraction on antioxidant and cytotoxic activities of lycopene-rich fractions of decanted pink guava by-product (decanter) were determined with lycopene-equivalent antioxidant capacity, β-carotene bleaching and MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide) assays. Extraction with SC-CO₂ gave a higher yield than solvent extraction (3.15 vs. 0.68 mg/100 g dried decanter, corresponding to 42.99 and 33.63 mg of lycopene). No cytotoxicity was found in Chang liver cells supplemented with either extracts (6.25–200 μg/ml). Solvent extract at 25 μg/ml (2.32 μM lycopene) and SC-CO₂ extract at 200 μg/ml (5.09 μM lycopene) had protective effect against hydrogen peroxide-induced cytotoxicity. However, only high concentrations of solvent extract (200 μg/ml; lycopene = 18.65 μM) or lycopene standard (10 μM) protected cells against DNA damage. Supercritical fluid extraction demonstrated a higher yield in lycopene-rich fraction from decanter. These fractions have the potential to be developed as a functional ingredient to prevent oxidative stress and other related diseases.     

Recovery of lycopene from industrially derived tomato processing by-products by pulsed electric fields-assisted extraction

The influence of pulsed electric fields (PEF) pre-treatment at different field strength (E = 1–5 kV/cm) and energy input (W_T = 5–10 kJ/kg) on the recovery yield of lycopene in either acetone or ethyl lactate from industrial tomato peels residues, was investigated. The rate of lycopene extraction in both solvents decreased with time and was predicted rather satisfactorily (R² = 0.96–0.99) by the Peleg's model. Micrograph of tomato peels showed that PEF induced size reduction and separation between the plant cells likely due to pore formation and leakage of intracellular matter. Coherently, PEF treatment (5 kV/cm, 5 kJ/kg) significantly enhanced the extraction rate (27–37%), the lycopene yields (12–18%) and the antioxidant power (18.0–18.2%) in either acetone and ethyl lactate extracts, as compared with untreated samples. However, acetone gave the highest lycopene yield. HPLC analyses revealed that all-trans lycopene was the main carotenoid extracted and no degradation/isomerization phenomena occurred. The results obtained in this work suggest that the application of PEF prior to solid-liquid extraction with environmentally friendly solvents could represent a sustainable approach for the valorization of industrial tomato peels residues.Industrial relevanceIndustrial processing of tomatoes generates large amount of by-products, mainly peels, which represent a cheap and abundant source of natural carotenoids, especially lycopene. The recovery lycopene from tomato peels residues is a crucial step for use in a wide range of industrial applications in food, cosmetic and pharmaceutical sectors as natural pigment and antioxidant. PEF pre-treatment allows to intensify the extractability of lycopene from of tomato processing by-products using environmentally friendly solvents, thus adding new value to the tomato processing chain, improving economic performances and decreasing waste problems.     

Lycopene extraction from tomato peel by-product containing tomato seed using supercritical carbon dioxide

This work discusses the extraction of lycopene from tomato peel by-product containing tomato seed using supercritical carbon dioxide. The presence of tomato seed in the peel by-product improved the yield of extracted lycopene. Extraction was carried out at temperatures of 70-90 °C, pressures of 20-40 MPa, a particle size of 1.05 ± 0.10 mm and flow rates of 2-4 mL/min of CO₂ for 180 min extraction time. Oil from tomato seed was extracted under similar operating conditions and analyzed using GC-MS and GC-FID, while carotenoids extracted were analyzed by HPLC. The optimum operating condition to extract lycopene, under which 56% of lycopene was extracted, was found to be 90 °C, 40 MPa, and a ratio of tomato peel to seed of 37/63. The presence of tomato seed oil helped to improve the recovery of lycopene from 18% to 56%. The concentration of lycopene in supercritical carbon dioxide as a function of density at various temperatures was determined.     

Carotenoid compositions of coloured tomato cultivars and contribution to antioxidant activities and protection against H2O2-induced cell death in H9c2

The carotenoid compositions, antioxidant activities and the potential cardio-protective role of 13 tomato cultivars with distinct colour were studied. Colour coordinates were evaluated by colorimeter and the carotenoid compositions were analysed by UPLC. Red tomatoes had the highest total carotenoid contents (TCC) and antioxidant activities, followed by purple, orange, pink and yellow ones. The TCC were 120.5–278.0 μg/g DW, and the antioxidant activities were 21.32–40.07 μmol TE/g DW (PCL), 64.42–89.98% (DPPH) and 10.47–13.76 μmol TE/g DW (ORAC), respectively. The lipophilic extracts were also found to prevent cell death in a cell-based model system using cardiac H9c2 cells and H₂O₂, via attenuation of the caspase-3 and matrix metalloproteinase-2 activities. The extracts of different tomatoes showed strong but different antioxidant activities. Roles of total and individual carotenoids in the antioxidant activities were studied and lycopene showed the highest correlation. Results of this study can be used to guide the development of new tomato cultivars and functional foods, and benefit the consumers.     

Effects of supercritical fluid extraction parameters on lycopene yield and antioxidant activity

The effects of various parameters of supercritical carbon dioxide (SC-CO₂) fluid extractions of tomato skins on the extraction yields and antioxidant activities of lycopene-rich extracts were investigated. A Box–Behnken design was applied to study the effects of three independent variables (temperature ranging from 40 to 100 °C, pressure ranging from 20 to 40 MPa, and flow rate ranging from 1.0 to 2.0 mL/min) on lycopene yield. The model showed good agreement with the experimental results, by the coefficient of determination (r² = 0.9834). Temperature, pressure, and the quadratic term for the temperature of SC-CO₂ extraction were large significantly positive factors affecting lycopene yield (P < 0.05). The maximum total lycopene content of 31.25 μg/g of raw tomato was extracted at the highest temperature of 100 °C, 40 MPa and 1.5 mL/min. TEAC assay was applied to assess the antioxidant activity of lycopene-rich extracts from SC-CO₂ fluid extraction. The effects of SC-CO₂ fluid extraction parameters on the antioxidant activities of the extracts differed with the yield. For each unit of lycopene extract, the antioxidant activity level was constant below 70 °C, but then gradually decreased above 70 °C due to isomerization occurring as a result of the higher temperature. The ratio of all-trans-lycopene to the cis-isomers changed from 1.70 to 1.32 when the operating temperature was adjusted from 40 to 100 °C, indicating an increased bioavailability due to the generation of the cis-isomers. No significant effects of pressure or flow rate of SC-CO₂ fluid extraction on the antioxidant activity were observed.     

Changes in pectin methylesterification and accumulation of methanol during production of diced tomatoes

The degree of methylesterification (DM) of the pectins in tomatoes affects the firmness of diced products and the consistency of juices. We examined the changes in DM that occur during commercial production of diced tomatoes packed in tomato juice. Ripe processing tomatoes contained low amounts of free methanol (<20 μg g fresh weight⁻¹) and had a high degree of pectin methylesterification (60%). During production of diced tomatoes, the level of free methanol increased while the degree of pectin methylesterification decreased. Diced tomatoes canned in tomato juice contained about 200 μg methanol g fresh weight⁻¹, and had a DM of about 35% in the dice and less than 25% in the juice. Similar results were obtained for aseptically processed bulk packed tomatoes. Low-temperature blanching of canned diced tomatoes caused additional pectin de-esterification in the diced tomatoes and improved firmness. Heating of the diced tomatoes prior to mixing with topping juice, first to temperatures that maximally activate PME then to temperatures that inactivate PME and other enzymes, is proposed as a way to both improve dice firmness and preserve the consistency of the topping juice.     

Apparent solubility of lycopene and β-carotene in supercritical CO2, CO2 + ethanol and CO2 + canola oil using dynamic extraction of tomatoes

Lycopene and β-carotene were extracted from freeze-dried tomatoes (skin + pulp) with pure SC CO₂ and SC CO₂ + 5% w/w co-solvent at 40 °C, 400 bar and flow rates of 0.5 and 1.2 L/min. The apparent solubility of lycopene and β-carotene in the multicomponent complex system was determined from dynamic extraction experiments using a laboratory-scale supercritical extraction system. Solubility of pure lycopene and β-carotene in SC CO₂ (binary system) was reported in the literature to be of the order of 10⁻⁶ mole fraction. The apparent solubility of lycopene extracted from tomatoes with SC CO₂ (multicomponent complex system) under the same conditions was almost one order of magnitude smaller. The apparent solubility obtained using oil as a co-solvent was higher than that obtained with ethanol as a co-solvent or pure SC CO₂. The differences in solubility are mainly due to the polarity of the co-solvent and the impact of the tomato matrix in the multicomponent complex system.     

Effect of extraction conditions on lycopene extractions from tomato processing waste skin using response surface methodology

Skin, rich in lycopene, is an important component of waste originating from tomato paste manufacturing plants. A central composite design with five independent variables, namely solvent/meal ratio (20:1, 30:1, 40:1, 50:1, and 60:1 v/w); number of extractions (1, 2, 3, 4 and 5); temperature (20, 30, 40, 50 and 60 °C); particle size (0.05, 0.15, 0.25, 0.35 and 0.43 mm); extraction time (4, 8, 12, 16 and 20 min) was used to study their effects on lycopene extraction. The experimental values of lycopene ranged between 0.639 and 1.98 mg/100 g. The second order model obtained for extracted lycopene revealed a coefficient of determination (R²) of 0.99 and a standard error of 0.03. Maximum lycopene (1.98 mg/100 g) was extracted when the solvent/meal ratio, number of extractions, temperature, particle size and extraction time were 30:1 v/w, 4, 50 °C, 0.15 mm and 8 min, respectively.     

ANTAGONISTIC EFFECT OF CPTA AND FAR-RED LIGHT ON THE CAROTENOGENESIS IN LUTESCENT TOMATOES1

Yellow lutescent tomatoes normally devoid of lycopene can be induced to produce this red pigment when treated with bioregulators such as CPTA, (2-(4-chlorophenylthio)-triethylamine hydrochloride). Red light and CPTA combination stimulated the accumulation of 225 μg/g of lycopene in mature white lutescent tomatoes after a 12-day ripening period. Tomatoes treated with CPTA but ripened in the dark produced 67 μg/g of lycopene. Far-red light treatment of the CPTA treated tomatoes produced only 25 μg/g of lycopene. Analysis of other carotenoids showed a similar trend indicating a quantitative but not a qualitative change in carotenogenesis in lutescent tomatoes as affected by light and by bioregulators. The antagonistic effect of far-red light toward CPTA suggested that the two effectors might work at the same reactive site in tomato cells.     

酶辅助超临界萃取番茄红素工艺研究

以番茄为原料,通过单因素试验及正交试验,研究酶辅助超临界CO2流体萃取番茄红素的工艺条件。结果表明,果胶酶和纤维素酶破壁处理的最佳反应条件为温度40℃、pH4.0、加酶量为4%果胶酶和3%纤维素酶、反应时间1.5h;超临界CO2流体萃取番茄红素的最佳工艺条件为萃取压力15Mpa、萃取温度40℃、萃取时间4h。     

Enzymatic water extraction of taxifolin from wood sawdust of Larix gmelini (Rupr.) Rupr. and evaluation of its antioxidant activity

An enzyme incubation–water extraction (EI–WE) method was developed and optimised for the extraction of the natural antioxidant taxifolin and of the total flavonoids from wood sawdust of Larixgmelini (Rupr.) Rupr. A factorial design and a central composite design approach were used for method optimisation. Optimal conditions were 0.5 mg/ml cellulase and 0.5 mg/ml pectinase, a pH of 5.0, a temperature of 32 °C and 18 h incubation time. The flavonoids and taxifolin were extracted in hot water at 50 °C for 30 min, with a solid to liquid ratio of 1:20. Under optimised conditions, the yields of taxifolin and total flavonoids increased from 1.06 ± 0.08 to 1.35 ± 0.04 mg/g and 4.13 ± 0.17 to 4.96 ± 0.29 mg/g, respectively. DPPH and BHT assays revealed that the EI–WE samples had 1.8- and 1.68-fold higher antioxidant activities than the controls. SEM results revealed the structural disruption of wood sawdust with enzyme incubation.     

番茄皮渣中番茄红素和多糖的提取

以番茄皮渣为原料,采用酶辅助双水相法提取番茄红素和多糖。考察溶剂与盐质量分数、混合酶的组成、酶质量分数、pH、酶解温度及酶解时间对有效成分得率的影响,并采用响应面法对工艺条件进行优化。结果表明:当双水相体系组成为31%乙醇-16%K2HPO4,果胶酶-菠萝蛋白酶为1∶1,酶质量分数为2.0%,在pH 6.0,50℃条件下酶解119 min时,番茄红素和多糖提取得率最高,分别为15.69 mg/100 g和77.16 mg/g。响应面法结果显示,酶质量分数对番茄红素和多糖的提取影响最为显著,其提取结果与预测值相符。与传统溶剂法相比,酶辅助双水相提取法溶剂用量少,提取温度低,提取物具有较好的抗氧化活性。     

Changes in the carotenoid concentration in human postprandial chylomicron and antioxidant effect in HepG2 caused by differently processed fruit and vegetable soups

Ten subjects consumed one serving of an optimised or a reference soup produced using modified or traditional processing methods, respectively. Both soups contained the same proportions of carrot, tomato and broccoli, but with 5% olive oil in the optimised soup and 2.5% in the reference soup. The β-carotene content in 600 mL of the optimised/reference soups was 4.10/2.90 mg, and the lycopene content was 3.90/2.71 mg. The β-carotene and lycopene concentrations in chylomicrons isolated from blood serum samples were similar for both groups. Only 50% of subjects could be considered as carotenoid responders and, in agreement with in vitro accessibility data, the β-carotene concentration in the chylomicrons of these subjects was significantly higher in the group consuming the optimised soup, while no changes were found for lycopene. Postprandial chylomicrons from the optimised soup group exhibited significantly higher antioxidant activity in HepG2 cells than the other group. The stimulation of HepG2 cells by human postprandial chylomicrons seems useful for evaluating the antioxidant effect of different food matrices.