Subcritical water extraction of phenolic compounds from potato peel

Potato peel, a waste generated from potato processing, is a disposal problem. But, potato peel is a good source of functional ingredients such as phenolic compounds. This study investigated the extraction of eight phenolic compounds (Gallic acid, GAC; Chlorogenic acid, CGA; Caffeic acid, CFA; Protocatechuic acid, PCA; Syringic acid, SGA; p-hydroxyl benzoic acid, PBA; Ferulic acid, FRA and Coumaric acid, CMA) from potato peel using subcritical water.Experiments were performed in a batch stainless steel reactor at 6 MPa, 2 mL/min and temperatures ranging from 100 to 240 °C at residence time of 30 to 120 min. High recoveries of phenolic compounds (81.83 mg/100 g; wet basis wb) were obtained at 180 °C and extraction time of 30 min compared to 3 h extraction with methanol (46.59 mg/100 g wb). CGA (14.59 mg/100 g wb) and GAC (29.56 mg/100 g wb) were the main phenolic compounds obtained from potato peel at 180 °C. Subcritical water at 160 to 180 °C, 6 MPa and 60 min might be a good substitute to organic solvents such as methanol and ethanol to obtain phenolic compounds from potato peel.     

Optimization of microwave-assisted extraction of phenolics from potato and its downstream waste using orthogonal array design

While other extraction methods have been tempted, a microwave-assisted extraction (MAE) method coupled with the orthogonal array design was investigated for efficient extraction of the phenolic compounds in potato downstream wastes. Four parameters were examined for the MAE of the total phenolic content (TPC) and optimized at 60% ethanol, 80 °C, 2 min, solid-to-solvent ratio 1:40 (g/ml). The MAE was proven more efficient than the conventional solvent extraction by refluxing. The optimized model showed that the downstream wastes, both the supernatant and the residue contained high TPC, particularly the former (11.0 ± 0.26 mg GAE/g DW). The antioxidant activities (DPPH and FRAP) closely correlated with the TPC of the samples (r = 0.92–0.97). Chlorogenic acid and caffeic acid were found to be the predominant phenolic acids. The extracts of the downstream wastes from potato processing can be a promising candidate for functional foods and nutraceutical ingredients.     

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.     

Response surface optimisation for the extraction of phenolic compounds and antioxidant capacities of underutilised Mangifera pajang Kosterm. peels

The optimum extraction conditions for highest recovery of total phenolics content (TPC) and antioxidant capacities (AC) were analysed for Mangifera pajang peels (MPP), using response surface methodology. The effects of ethanol concentration (X₁: 20–80%), extraction temperature (X₂: 30–65 °C) and liquid-to-solid ratio (X₃: 20–50 mL/g) on the recovery of total phenolics (Y₁) and antioxidant capacity (Y₂) were investigated. A second order polynomial model produced a satisfactory fitting of the experimental data with regard to total phenolic content (R² = 0.9966, p < 0.0001) and antioxidant capacity (R² = 0.9953, p < 0.0001). The optimum extraction conditions for TPC were 68%, 55 °C and 32.7 mL/g, and for AC were 68%, 56 °C and 31.8 mL/g, respectively. Predicted values for extraction of TPC and AC agreed well with the experimental values. Liquid chromatography–mass spectrometry of the optimally obtained extracts from MPP revealed the major phytochemicals as mangiferin, gallic acid, catechin and epicatechin.     

石榴皮中抗氧化物质提取条件的响应面优化

对石榴皮中抗氧化活性物质提取工艺及其成分分析进行研究,通过单因素实验和响应面优化,得到石榴皮中抗氧化物质提取工艺条件为:液固比为26mL/g、提取温度为59℃、提取时间100s、微波功率为500W,水提,此条件得到的提取物对DPPH自由基的清除率达91.067%。提取物活性成分分析表明:提取物中总多酚含量为165.67mg/g,总黄酮64.88mg/g,多糖125.04mg/g,原花青素9.16mg/g。     

香蕉皮中果胶提取工艺的研究

采用盐析的沉淀方法对香蕉皮果胶的提取工艺进行了系统研究。通过L9(34)正交实验,得出酸解工艺的最优化条件为:以pH1.5的盐酸溶液为萃取剂、液料比5mL/g、温度95℃、时间2h、螯合剂六偏磷酸钠添加量为0.3%;盐析的最优化条件为:每100mL果胶液中加入7mLAl2(SO4)3饱和溶液,边均匀搅拌边用浓氨水调pH至4.5左右,70℃保温45min;果胶盐脱盐的条件为:每5g果胶盐置于200mL脱盐液(组成为60%乙醇 3%盐酸 37%水,V/V)中,边搅拌边脱盐30min左右,所得果胶产量0.7846g。     

Enzymatic extraction of galactan-rich rhamnogalacturonan I from potato cell wall by-product

Potato cell wall was used as low-value source for the enzymatic extraction of galactan-rich rhamnogalacturonan I (RG I). The effects of selected reaction parameters of endo-polygalacturonase from Aspergillus niger-catalyzed isolation of RG I and their interactions were investigated by response surface methodology. Models were developed to relate independent parameters (cell wall concentration, enzyme amount, reaction time) to responses (yield, neutral sugar content, saccharide molar composition, weak acidic fraction proportion). The most significant parameters that affected extracted polysaccharide yield and its galactose (Gal) and arabinose (Ara) contents were the cell wall concentration and enzyme amount. The interaction between the cell wall concentration and the reaction time was the most determinant for the yield. However, the cell wall concentration and the enzyme amount exhibited significant interaction effect on Gal and Ara contents. Comparison of predicted and experimental values validated the established predicted models, which can be used to identify the conditions for the isolation of RG I-type pectic polysaccharides with selected structural and saccharide composition properties. The monosaccharide composition and the linkage patterns confirmed the isolation of galactan-rich RG I type pectic polysaccharides. The present study is expected to increase the capability to generate RG I targeting specific composition and functional properties.     

Ultrasound-assisted extraction of polyphenols (flavanone glycosides) from orange (Citrus sinensis L.) peel

The present study reports on the extraction of polyphenols especially flavanones from orange (Citrus sinensis L.) peel by using ethanol as a food grade solvent. After a preliminary study showing that the best yield of extraction was reached for a particle size of 2 cm², a response surface methodology (RSM) was launched to investigate the influence of process variables on the ultrasound-assisted extraction (UAE) followed by a central composite design (CCD) approach. The statistical analysis revealed that the optimised conditions were a temperature of 40 °C, a sonication power of 150 W and a 4:1 (v/v) ethanol:water ratio. The high total phenolic content (275.8 mg of gallic acid equivalent/100 g FW), flavanone concentrations (70.3 mg of naringin and 205.2 mg of hesperidin/100 g FW) and extraction yield (10.9 %) obtained from optimised UAE proved its efficiency when compared with the conventional method. Furthermore, the antioxidant activity determined by the DPPH and ORAC tests confirmed the suitability of UAE for the preparation of antioxidant-rich plant extracts.     

超声波辅助提取菠萝皮多酚物质的研究

研究了超声波辅助提取菠萝多酚物质的工艺,对影响多酚浸提率的因素进行了单因素试验和正交试验,确定了最佳工艺条件为:乙醇浓度60%,浸提温度45℃,功率200W,浸提时间60min,液料比15.0∶1.0。在此条件下,浸提率可达18.48g/kg。     

从柑桔皮中超声提取橙皮苷

从柑桔皮中连续提取色素、果胶和橙皮苷。浸提果胶后的滤渣,在超声波作用下,利用饱和Ca(OH)2碱液浸提盐酸酸析得到橙皮苷。最佳工艺条件为:碱提pH12.5,液料比10:1,超声时间60min,酸析pH4.7,浸提级数3级。另外,考察了重结晶法精制对橙皮苷纯度的影响,平均纯度为94.96%,提高14.72%。红外光谱、高效液相色谱等方法表征实验产品是橙皮苷。     

多频超声波辅助提取石榴皮中原花青素的研究

介绍了从石榴皮中提取原花青素的工艺,研究了不同超声波频率、提取时间、超声波功率和提取料液比对原花青素提取率的影响.试验结果表明,最佳提取条件为:超声波频率60 kHz,提取时间65 min,超声波功率100 W,提取料液比1:10,此条件下的提取量为16.996 mg/g.     

加速溶剂萃取技术提取柑橘皮中总黄酮的工艺研究

应用加速溶剂萃取技术,通过单因素试验和正交试验对柑橘皮中总黄酮提取工艺进行了研究。结果表明,用加速溶剂萃取技术从柑橘皮中提取黄酮的最佳工艺条件为压力10.3MPa、乙醇浓度80%、料液比1∶15、温度70℃、浸提时间10min,此时黄酮得率为2.64%。     

微波辅助提取苹果皮中的多酚类物质

以苹果皮为原料提取苹果多酚,对不同提取剂的提取效果进行了比较;通过单因子试验和正交试验对微波辅助提取多酚的工艺条件进行了探讨,研究了溶剂浓度、微波功率、微波处理时间以及料液比对多酚提取的影响;并对微波辅助提取和常规法提取的效果进行了比较。结果表明：综合考虑提取效果及食品安全性,选择乙醇作为提取剂为宜;微波辅助提取的最佳工艺条件为乙醇浓度70%、微波功率210W、微波时间25s、料液比（w/v）1∶5;微波辅助提取法提取物中原花色素含量0.3668mg/ml,常规法提取物中原花色素含量0.2552mg/ml,微波辅助提取效果优于常规法提取。     

微波辅助提取石榴皮多酚工艺研究

研究从石榴皮中微波辅助提取多酚的工艺.采用单因素试验及正交试验,考察不同条件下石榴皮多酚提取率.结果表明,提取溶剂乙醇体积分数、微波功率、提取时间得料液比均对石榴皮多酚提取率有显著影响;石榴皮多酚的最佳提取条件为50％(体积分数)乙醇作溶剂,微波功率300W,提取时间120s,料液比1∶35(m∶V).该条件下提取石榴皮多酚,提取率可达21.41％.     

超声波提取橘皮中柠檬苦素化合物的工艺研究

研究了超声波法从温州蜜柑果皮中提取柠檬苦素化合物的工艺,探讨溶剂种类及浓度、料液比、超声时间、提取温度对柠檬苦素化合物提取率的影响。通过正交实验确定其最佳提取工艺条件为:65%乙醇溶液、料液比1:30(g/mL)、超声18min、提取温度60℃,提取率为6.25mg/g。     

酶法制取橙皮果胶的研究

纤维素酶酶系组成复杂,不同来源纤维素酶在果胶提取中表现出的作用不同。采取与前人研究不同的纤维素酶对橙皮果胶进行提取,对三种不同来源的纤维素酶比较分析,筛选出一种价格低廉、适合果胶提取的纤维素酶,并采用四元二次通用旋转组合设计方法研究了其提取果胶工艺中缓冲溶液的pH、提取时间、酶添加量、提取温度对果胶得率的影响;建立数学模型,寻求测定条件的最优组合;以DesignExpert软件进行分析,模型经检验差异显著,失拟检验不显著,具有良好的统计学意义,最优组合为:酶添加量3.38mL、时间6.66h、温度47.5℃、pH4.95,预测模型果胶得率为14.43%,验证实验得率为14.79%,大大提高了纤维素酶制取果胶的得率,远远高于文献报道,并且酶的价格低廉,大大降低了生产成本。     

Response surface methodology for optimisation of soluble dietary fibre extraction from sweet potato residue modified by steam explosion

To make better use of sweet potato residue (SPR), a new pretreatment method, steam explosion (SE), can increase its content of soluble dietary fibre (SDF). Response surface methodology (RSM) was used to determine the SE variables for optimum SDF yield. The optimal conditions were a steam pressure of 0.35 MPa, a residence time of 121 s and a sieving mesh size 60. Under the optimised conditions, the content of SDF from SPR reached 22.59 ± 0.35%, an increase of 18.78% compared with that (3.81 ± 0.62%) from untreated SPR. The water‐holding capacity, oil‐holding capacity (OHC) and swelling capacity of SDF were improved by SE. Scanning electron micrograph (SEM) images demonstrated that SDF had become poriferous, loose and dilatants after SE treatment. This technology provides an efficient process for increasing the industrial production of SDF from SPR.     

Response surfaces of hazelnut oil yield in supercritical carbon dioxide

Response Surface Methodology was used to determine the effects of solvent flow rate (1, 3 and 5 g/min), pressure (300, 375 and 450 bar) and temperature (40, 50 and 60 °C) on hazelnut oil yield in supercritical carbon dioxide (SC-CO₂). Oil yield was represented by a second order response surface equation (R²=0.997) using Box-Bhenken design of experiments. Oil yield increased with increasing SC-CO₂ flow rate, pressure and temperature. The maximum oil yield was predicted from the response surface equation as 0.19 g oil/g hazelnut (34% of initial oil) when 4 g hazelnut particles (particle diameter<0.85 mm) were extracted with 5 g/min SC-CO₂ flow rate at 450 bar, and 60 °C for 10 min. Total extraction time at these conditions was predicted to be 35 min.     

柚皮纤维素的提取工艺研究

以柚皮为原料,采用化学分离方法对其中纤维素的提取工艺进行了研究,以得到对重金属离子有较高吸附能力的纤维素。通过单因素实验,研究了提取过程中氢氧化钠浓度、过氧化氢浓度、脱色温度和脱色时间等工艺参数,在此基础上进行正交实验,通过极差分析确定了最佳的工艺条件,即氢氧化钠浓度为6%、过氧化氢浓度为10%、脱色时间30min和脱色温度为30℃时,柚皮纤维素含量最佳,为67.7%,对Cu2+、Pb2+的吸附容量分别为76.9mg/g与96.4mg/g,产品为乳白色粉末,带有略微柚香。     

柠檬皮中果胶物质的提取研究

通过酸水解的方法,探索了柠檬皮中果胶物质的提取条件,研究结果表明,当样品浸泡2.5h后,在pH值为2.2的95℃水中水解2.8h,柠檬皮中果胶的提取率可达15.6%。