猪胰脏中胰酶的提取工艺优化研究

目的：采用异丙醇为提取剂,一种新型沉淀剂壳聚糖对猪胰脏中胰酶的制备工艺进行研究。方法：通过单因素试验和正交试验,对影响胰酶收率和活力的因素(异丙醇浓度、提取时间、pH 值、壳聚糖用量)进行研究,确定最佳工艺条件。结果：所得的最佳工艺条件为异丙醇浓度7.5%、提取时间6h、pH4、壳聚糖用量0.1%。结论：所制得的胰酶收率为12.19%,胰蛋白酶、胰淀粉酶和胰脂肪酶的酶活分别为4836、14320、20580U/g,说明壳聚糖有很好的沉淀絮凝效果。     

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。     

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.     

An Improved Ultrasonic-Assisted Extraction Method by Optimizing the Ultrasonic Frequency for Enhancing the Extraction Efficiency of Lycopene from Tomatoes

In order to assess the optimization of the ultrasonic frequency in a range of 18–146 kHz for extracting lycopene from tomatoes and evaluate its influence on the extraction efficiency, an improved ultrasonic-assisted extraction (IUAE) method was proposed by using a novel ultrasonic extraction and detection system, in which the ultrasonic frequency information could be converted to intuitive waveforms that are easily identified by eyes. Additionally, to improve the extraction yield of lycopene, in this work, the optimization of various process parameters by ultrasonic treatment, including extraction time, solvent/material ratio, extraction temperature, and ultrasonic power for improving the yield of lycopene were investigated. These results indicated that all of the considered parameters had effected on the yield of lycopene significantly, and the optimum extraction conditions were as follows: extraction time duration 20 min; ratio of solvent to material 2:1; extraction temperature 25 °C; ultrasonic power 200 W; ultrasonic frequency 46–48 kHz. In comparison with other extraction methods, such as conventional solvent extraction (CSE), supercritical fluid extraction (SFE), supercritical carbon dioxide co-extraction (SC-CO₂), and existing UAE, the IUAE method achieved a far more extraction yield, a reduction of extraction time, and a smaller amount of solvent at lower temperature, which showed a great promising prospect in the extraction and separation of natural products.     

Optimisation of biological and physical parameters for lycopene supercritical CO2 extraction from ordinary and high‐pigment tomato cultivars

BACKGROUND: Lycopene is used for several industrial applications. Supercritical CO₂ (SC‐CO₂) extraction from red‐ripe tomato fruits is an excellent technique to replace the use of harmful solvents. In this study, starting from red‐ripe tomatoes of ordinary and high‐lycopene cultivars, the effect of different agronomical and technical aspects on lycopene content, stability and yield was evaluated throughout the production process from fresh tomatoes to the final SC‐CO₂‐extracted oleoresin containing lycopene. RESULTS: Red‐ripe tomato cultivars differed in their lycopene content. Irrigation excess or deficit caused an increase in the amount of lycopene in the fruits. Fresh tomatoes were processed into a lyophilised matrix suitable for SC‐CO₂ extraction, which could be stored for more than 6 months at ? 20 °C without lycopene loss. Under the optimal extraction conditions, efficiencies of up to 80% were achieved, but the recovery of lycopene in the extracted oleoresin was very low (～24%). Co‐extraction of the tomato matrix mixed with a lipid co‐matrix allowed the recovery of ～90% of lycopene in the oleoresin. Using the high‐lycopene cultivars, the yield of total extracted lycopene increased by ～60% with respect to the ordinary cultivars. Lipids and other biologically active molecules were present in the oleoresin. CONCLUSION: A method for extracting, from a tomato matrix, a natural and solvent‐free oleoresin containing lycopene dissolved in a highly unsaturated vegetable oil has been described. The oleoresin represents an excellent product for testing on cancer and cardiovascular disease prevention. Copyright © 2010 Society of Chemical Industry     

番茄红素不同提取工艺及其对性质影响

以新鲜番茄为试材提取番茄红素,比较研究微波法和有机溶剂浸提法两种工艺及其对番茄红素性质影响。结果表明,最佳提取溶剂为氯仿-丙酮(2:1);有机溶剂浸提最佳条件为:浸提温度40℃,料液比1:4,提取时间70min,浸提次数3次,提取率为89.89%;微波提取最佳条件为:料液比1:3,微波功率360W,微波时间15s,提取次数2次,各因素中微波功率和微波时间影响最小,微波起辅助作用,提取率为97.58%,比有机溶剂浸提高出7.69%,且节省时间和溶剂;微波提取所得产品纯度较高,无溶剂痕量残留。两种工艺所得番茄红素性质基本相同,对光、高温、酸、高浓度NaSO3,高浓度Ca2+和Cu2+,Fe3+等不稳定;对氧化剂、低浓度NaSO3、碱、Na+、K+、苯甲酸钠、Vc和柠檬酸等基本稳定,且弱碱有轻微增色作用。     

番茄红素的简便提取与贮藏稳定性研究

用两步溶媒法提取番茄酱中番茄红素，并研究了番茄红素提取物的贮藏稳定性，结果表明：两步溶媒法溶剂用量少，提取时间短，所得产物的番茄红素含量大于90％，提取率高达92．17％。番茄红素分散于含0．012％(W／W)VE或0．012％(W／W)VE和0．015％(W／W)迷迭香抗氧剂的亚麻籽油中，室温避光贮藏三个月很稳定。     

Microwave-assisted extraction of chlorogenic acids from green coffee beans

Microwave-assisted extraction (MAE) has been considered as a potential alternative to conventional solvent extraction for the isolation of phenolic compounds from plants. Aqueous and alcoholic extracts of green coffee bean obtained by MAE were quantitatively analysed for total yield of extracts, chlorogenic acids, caffeine and total polyphenol content. The extracts were also evaluated for radical-scavenging activity, using 1,1-diphenyl-β-picrylhydrazyl radical. Under optimum conditions of time (5 min), temperature (50 °C) and wattage (800 W), the maximum chlorogenic acids and caffeine could be extracted with water as solvent. The extracts contained chlorogenic acids and caffeine in the ranges of 31–62% and 22–40%, respectively. The yields of MAE under optimum conditions were higher than those from the conventional solvent extraction at 5 min and 50 °C and the extracts showed radical-scavenging activity of >75%, even at the concentration of 25 ppm. The MAE process can thus be predicted and controlled for industrial application.     

溶剂浸提秋橄榄果实中番茄红素工艺优化

分别采用乙酸甲酯、丙酮、石油醚、二氯甲烷4种浸提剂,设计3种提取方法对成熟秋橄榄浆果中番茄红素的提取效果进行评价和分析,获得优化小试提取工艺参数：在避光环境下,乙酸甲酯为浸提剂,料液比1:40(g/mL),边研磨边浸提,循环浸提4次,真空浓缩蒸干温度为57.8℃,此法可从秋橄榄浆果中获得番茄红素34.81mg/100g,回收溶剂可重复利用,浓缩粗提物中番茄红素质量浓度达6.4～7.5mg/100mL。乙酸甲酯适合作为秋橄榄番茄红素的提取溶剂。     

响应曲面法优化番茄皮渣中番茄红素提取工艺的研究

采用乙酸乙酯从番茄皮渣中提取番茄红素并结合紫外分光光度法测定其含量。在单因素试验的基础上,利用响应曲面法优化了提取工艺,建立了浸提温度、浸提时间、液固比与提取率之间的数学模型,确定了番茄红素提取的最佳工艺条件,即以乙酸乙酯为浸提溶剂、浸提温度51℃、浸提时间2.3h、液固比8.9:1(V/g),在此最佳工艺条件下进行提取,番茄红素提取率为(28.74±0.05)%(n=3)。     

Optimisation of microwave‐assisted extraction of Gac oil at different hydraulic pressure,microwave and steaming conditions

The study aimed to optimise Gac (Momordica cochinchinensis Spreng) oil extraction conditions, including microwave time, steaming time and hydraulic pressure, for maximising extraction efficiency (EE), and β‐carotene and lycopene contents, using response surface methodology. Results indicated that the data were adequately fitted into three second‐order polynomial models for EE, β‐carotene and lycopene with R² values of 0.93, 0.85 and 0.86, respectively. It was predicted that the optimum extraction conditions within the experimental ranges would be the microwaving time of 62 min, steaming time of 22 min and hydraulic pressure of 175 kg cm^?2. Under such parameters, the maximum EE of 86%, β‐carotene content of 186 mg per 100 mL oil and lycopene content of 518 mg per 100 mL oil were achieved as predicted.     

The physico-chemical characteristics of extruded snacks enriched with tomato lycopene

Adding tomato derivatives to traditional starchy extruded snacks can improve their nutritional properties by adding lycopene and fibre; however the physico-chemical properties of these products must also be considered. Ingredients and extrusion parameters, including temperature, alter these properties, but their effect on lycopene content is not known. In this study, crisp low density extruded snacks were manufactured from corn, wheat and rice, with or without dried tomato skin or paste powder extruded at temperatures of 140, 160 or 180 °C. Lycopene content and the physico-chemical properties (expansion, density, hardness, colour parameters and percentage of moisture loss) of the extruded products were measured. Lycopene retention was higher in products containing tomato skin powder and significantly lower when wheat flour was used to make the snacks. Increases in the processing temperature improved the physico-chemical characteristics of the snacks but had no significant effect on lycopene retention (P > 0.05).     

Optimization of Extraction Conditions of Citrinin from Red Yeast Rice by Orthogonal Design and Quantification of Citrinin by High-Performance Liquid Chromatography

An orthogonal experimental design was utilized to optimize extraction condition of mycotoxin citrinin from red yeast rice. The results showed that the combination of the following conditions was the optimum extraction condition: 50 % ethanol as extraction solvent, 1:5 as the solid-to-liquid ratio, and vortex for 5 min followed by 20 min ultrasonication as extraction manner. Under the optimum extraction condition, citrinin in 11 commercial red yeast rice products was extracted and quantified by optimized high-performance liquid chromatography (HPLC) conditions which consisted of acetonitrile and acidic water (pH 2.5) as mobile phase, flow rate of 1 mL/min, and fluorescence detector. The quantification results showed that seven products contained citrinin; the highest content of citrinin was 57.28 μg/g. The citrinin contamination rate in collected red yeast rice samples was 63.6 %. This investigation indicates that the optimized extraction method followed by HPLC fluorescence detection is a sensitive and effective method to quantify citrinin. The results also indicate that most red yeast rice products in China contain citrinin. However, there are no national criteria about citrinin limit in red yeast rice and the related products. Therefore, a national regulation standard in terms of quantification method should be set up to limit citrinin contamination and to control the circulation of red yeast rice products in China.     

Angiotensin I-Converting Enzyme Inhibitory Activity of Soy Protein Digests in a Dynamic Model System Simulating the Upper Gastrointestinal Tract

ABSTRACT: The objective of this study was to investigate whether peptides with inhibitory activity against angiotensin I-converting enzyme (ACE) would be produced by digestion of isolated soy protein (ISP) in a dynamic model system simulating gastrointestinal conditions. Using the model system, 5% ISP solution was pumped into the stomach reactor containing pepsin and HCl. The peptic digest was continuously pumped into the duodenum reactor containing pancreatin and Oxgall bile. The effects of blanching (100°C, 10 min) followed by pasteurization (75°C, 15 s) or sterilization (121°C, 20 min) of ISP before digestion on the inhibitory activity were also investigated. During the first 30 min of digestion, significantly higher ( P < 0.05) ACE-inhibitory activity was generated from unheated ISP after sequential digestion in both reactors compared with after peptic digestion only in the stomach reactor. However, at 90 min, subsequent digestion by pancreatin of unheated and blanched-sterilized ISP decreased ACE-inhibitory activity compared with peptic digestion alone. The IC₅₀ values at the end of 90 min digestion in both reactors were 0.38 ±0.01, 0.37 ± 0.02, and 0.44 ± 0.02 mg/mL for unheated, blanched-pasteurized, and blanched-sterilized ISP, respectively. The results suggest the potential production of peptides with ACE-inhibitory activity upon physiological digestion of soy protein, including products that have been subjected to heat processing. Although clinical trials would be required to provide final evidence of efficacy of the soy peptides, the present findings support the application of soy protein as an ingredient for functional foods.     

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.     

Optimization of extraction of phenolic content from hazelnut shell using response surface methodology

Response surface methodology was applied to predict the optimum conditions for extraction of phenolic compounds in hazelnut shell. The phenolic content in the shell extract was determined spectrophotometrically according to the Folin‐Ciocalteu method and expressed as gallic acid equivalent (mg GAE g^?1). Two central composite designs were used to investigate the effects of two independent variables, namely solvent composition (%) and extraction time (min), on phenolic extraction. In a first series of repeated batch extractions, the solvent consisted of different methanol percentages in distilled water at pH 4, while in a second series methanol was substituted by ethanol. The highest phenolic content (6.67 mg GAE g^?1 of shell) was predicted at the extraction conditions of 55.7% ethanol and 108.7 min. These best conditions, obtained and applied to 13 different cultivars, showed values varying from 9.18 mg GAE g^?1 of shell for Barcelona to 3.00 mg GAE g^?1 of shell for Tonda di Giffoni. Copyright © 2007 Society of Chemical Industry     

Effects of Gac aril microwave processing conditions on oil extraction efficiency,and β-carotene and lycopene contents

The effects of Gac oil extraction conditions including microwave power, microwave time, steaming time and hydraulic pressure on extraction efficiency (EE), and β-carotene and lycopene contents were studied. It was found that the EE, and β-carotene and lycopene contents could be enhanced by suitable extraction conditions. Microwave drying was found to be better than air drying for pretreatment. Moisture content after drying and steaming between 8% and 11% (wt/wt) were best for pressing. Results showed that the most suitable conditions for Gac oil extraction from 900 g samples were microwave power of 630 W, microwave time of 65 min, steaming time of 20 min and hydraulic pressure of 170 kg/cm². Under these conditions, the highest EE of 93% was achieved while Gac oil contained the highest content of β-carotene and lycopene at 140 and 414 mg/100 mL, respectively.     

响应面试验优化超声辅助提取番茄皮渣中番茄红素工艺及其HPLC-MS测定

以番茄皮渣为原料,采用超声辅助提取工艺,研究提取溶剂种类、超声功率、液固比、提取时间、提取温度对番茄红素提取效果的影响,通过响应面试验分析,确定最佳工艺条件为：皮渣经95%乙醇溶液处理后,以乙酸乙酯为提取溶剂,提取温度50 ℃、提取时间45 min、液固比5∶1（mL/g）、超声功率270 W。产物经高效液相色谱-质谱测定,番茄红素提取量可达到250.1 mg/kg。通过组织结构观察,与传统提取方法相比,超声提取能有效破坏植物组织结构,提高提取效果。     

高顺式番茄红素制备工艺研究

番茄红素是一种具有优越生理活性的功能因子,相比天然全反式番茄红素,顺式结构的番茄红素具有更高的生物活性和生物利用率。以全反式番茄红素为原料,脂肪酸为溶剂,采用微波加热法对番茄红素进行异构化,探究脂肪酸,微波条件,催化剂对番茄红素异构化的影响。以番茄红素顺式占比为指标,通过单因素试验,对微波加热法制备高顺式番茄红素工艺进行优化。研究结果表明,微波温度81 ℃,微波功率600 W,微波时间11 min,亚油酸和辛癸酸甘油酯1:1比例添加3 mL,催化剂二烯丙基二硫添加量80 mg/mL,此条件下得到13Z,(5Z,9Z)及其他未知未知异构体组分番茄红素总顺式占比为(40.19±0.27)%。稳定性试验表明,温度越低,番茄红素保留率越高,等温条件下,反式最稳定,(5Z, 9Z)次之,13Z最不稳定。此方案可以有效提高番茄红素顺式占比,从而提高番茄红素在人体内的消化吸收,提高生物利用率,并为开发含番茄红素的功能食用油产品提供了理论依据。     

小米中VB2的提取方法研究及其含量的测定

通过单因素试验和正交试验分析研究不同提取液、提取方法和提取条件对小米中VB2 提取效果的影响。采用荧光分析法,在激发波长λex=471.0nm 和发射波长λem=528.0nm 时,测定小米中VB2 的含量。结果表明：选取H3PO4 溶液为提取液,用水浴回流法,提取液浓度0.1mol/L、提取时间45min、提取液pH5.0 时,提取效果最佳,且回收率可达到89.20%～100.32%,变异系数可控制在1.21% 内。实验精密度和准确度良好,可快速、准确的测定小米中VB2 含量。