High hydrostatic pressure assisted extraction of pectin from sugar beet pulp

This study aimed to investigate the effect of high hydrostatic pressure assisted extraction (HHPE) (250, 350 and 450 MPa at 40 °C for 5 min with/without acid addition) of pectin from sugar beet pulp and compare its properties with pectin obtained from conventional extraction (CE). Degree of esterification (DE), galacturonic acid (Gal-A) content, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) relaxometry experiments were performed on the obtained pectin powder. HHPE (12.23 ± 0.13%) doubled extraction yield compared to CE (6.43 ± 0.07%). Also, HHPE and acid addition were found to have a synergetic effect on the extraction. HHPE resulted in degradations in the polymer structure and reduced Gal-A content and DE. Pectin extracted with both methods was classified as low methoxyl pectin (LMP). According to the NMR Relaxometry results, HHPE decreased water holding capacity (WHC). In brief, HHP was shown to increase the pectin extraction yield and no changes in viscosity were observed at the concentrations studied (2 g/L).     

Effect of commercial enzymatic preparation with pectolytic activities on conventional extraction and ultrasound‐assisted extraction of oil from grape seed (Vitis vinifera L.)

Conventional solvent extraction (CE) and ultrasound‐assisted extraction (UAE) in hexane for oil from untreated and enzyme‐treated grape seeds were investigated and compared. Among the output power tested (50, 100 and 150 W) in UAE on untreated seeds, UAE at 150 W for 30 min with liquid‐to‐solid ratio 8:1 (v/w) gave oil extraction yield comparable to CE (ca. 14% w/w) for 6 h with liquid‐to‐solid ratio 12:1 (v/w). CE and UAE at 150 W did not influence the fatty acid profiles of oil. CE oil was found to be the most oxidised. The enzymatic treatments (2, 4 and 6 g per 100 g seeds of Rapidase^® Expression) prior to CE enhanced by 2.5% of the oil yield. Enzymatic treatments higher than 2 g per 100 g seeds increased relative value of some fatty acids both in CE and UAE. Enzymatic pretreatment from 2 to 4 g per 100 g seeds significantly improved some physicochemical parameters of oil quality when extracted by CE, but not by UAE.     

Green ultrasound and microwave extraction of carotenoids from passion fruit peel using vegetable oils as a solvent: Optimization,comparison, kinetics,and thermodynamic studies

The aim of this study was to examine the effect of green processes like ultrasonication assisted extraction (UAE) and microwave assisted extraction (MAE) using olive oil (OO) and sunflower oil (SO) as solvents on the extractability of carotenoids from passion fruit peel (PEP) that is discarded as waste. Using optimized conditions of UAE, 91.4% (OO) and 86.7% (SO) of the carotenoids present were extracted while MAE extracted 86.9% in OO. Comparison of energy density revealed that UAE is more efficient than MAE. UAE treated OO was acceptable for different quality parameters and the oil was enriched with carotenoids by more than three times and phenolic content by fifteen times. The extraction kinetics and thermodynamic studies for carotenoids extracted from PEP using UAE and CE (conventional extraction) processes with OO as solvent were performed at different combinations of extraction time and temperature. The extraction rate constant (k_s) for UAE and CE was in the range of 0.0022–0.0048 100 g/μg carotenoids min and 4.02 × 10⁻⁵ − 6.85 × 10⁻⁵ 100 g d.w./μg carotenoids min, respectively. The effective diffusion coefficient of UAE and CE for the extraction of carotenoids varied between 2.3740 ×10⁻¹³ and 2.8260 ×10⁻¹³ m²/s and 0.997×10⁻¹⁴and 2.336 ×10⁻¹⁴ m²/s, respectively and corresponding mass transfer rate ranged from 1.625 ×10⁻⁷ – 1.8731 ×10⁻⁷ m/s and 0.0728 ×10⁻⁸ – 0.1714 ×10⁻⁸ m/s. The kinetics information mainly rate constant, effective diffusivity and mass transfer coefficient obtained from the green extraction process using ultrasonication would allow the prediction of operation conditions for industrial implementation.     

Comparison of different Brazilian citrus by-products as source of natural antioxidants

Significant amounts of citrus by-products remain after juice processing, which is then used to obtain pectin. The pectin industry then generates a new waste. No study has characterized this residue or suggested applications for it. The main goal of this study was to compare citrus industrial by-products that remain after juice (CJB) and pectin (CPB) extraction, aiming to obtain bioactive compounds. The residues were evaluated for their chemical composition, antioxidant capacity, and polyphenols content. CJB had 2-fold higher total phenols than CPB. Moreover, CJB exhibited higher antioxidant capacity than CPB. Nine polyphenols were detected; hesperidin was the main compound on both residues. CPB had higher content of polyphenols than CJB, which can be attributed to the industry procedure of pectin extraction. Thus, this study provides support for the reuse of CPB to obtain nutraceutical compounds, converting waste into added-value products.     

Husk Tomato (Physalis ixocarpa Brot.) Waste as a Promising Source of Pectin: Extraction and Physicochemical Characterization

Husk tomato (Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly (P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics.     

Effect of extraction conditions on the quality characteristics of pectin from passion fruit peel (Passiflora edulis f. flavicarpa L.)

Passion fruit (Passiflora edulis f. flavicarpa L.) yellow variety is composed of 50-55 g peel per 100 g of fresh fruit which is discarded as waste during processing. Utilization of passion fruit peel for pectin extraction was studied. Passion fruit peel obtained after juice extraction was blanched in boiling water for 5 min, dehydrated in a cross flow hot air drier at 60 ± 1 °C to a moisture content of 4 g/100 g of dried peel. The dehydrated passion fruit peel was used for extraction experiments of pectin. The effect of pH, peel to extractant ratio, and number of extractions, extraction time and temperature on the yield and quality characteristics of pectin were investigated. The optimized conditions for extraction of pectin from passion fruit peel yielded 14.8 g/100 g of dried peel. Pectin extracted from the dried peels had a methoxyl content of 9.6 g/100 g, galacturonic acid content of 88.2 g/100 g and jelly grade of 200. Extraction of pectin from dried peels of passion fruit may be considered for effective utilization of passion fruit processing waste.     

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.     

Ultrasound‐assisted extraction of polyphenols from potato peels: profiling and kinetic modelling

Ultrasound‐assisted extraction (UAE) at 33 and 42 kHz has been investigated in the extraction of polyphenols from peels of two potato varieties, cream‐skinned Lady Claire (LC) and pink‐skinned Lady Rosetta (LR), commonly used in snack food production. Extraction efficacy between the UAE‐untreated (control) and the UAE‐treated extracts was assessed on the total phenolic content and antioxidant capacities (DPPH and FRAP). Application of UAE showed significantly higher recovery of phenolic compounds compared to solid–liquid extraction process alone. Lower ultrasonic frequency (33 kHz) was more effective in recovering polyphenols compared to 42 kHz ultrasonic treatment. The liquid chromatography‐tandem mass spectrometry revealed that chlorogenic acid and caffeic acid were the most prevalent phenolics in LR peels, whereas caffeic acid was dominant in LC peels. Peleg's equation showed a good correlation (R² > 0.92) between the experimental values and the predicted values on the kinetics of UAE of phenolic compounds.     

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。     

Utilization of ultrasound and pulse electric field for the extraction of water-soluble non-starch polysaccharide from taro (Colocasia esculenta) peel

This study investigated the effects of different extraction methods (i.e. conventional (CE), ultrasound-assisted (UAE), and pulse electric field-assisted (PEFAE)) on the yield and physico-chemical properties of the water-soluble non-starch polysaccharide (WS-NSP) from taro peel (Tp). The use of UAE resulted in a significantly (p ≤ 0.05) higher yield (3.65 g/100 g) than PEFAE (2.25 g/100 g) and CE (2.10 g/100 g). Tp-WS-NSP-UAE and Tp-WS-NSP-PEFAE had fewer impurities indicated by the lower amount of ash (UAE: 0.41; PEFAE: 0.20 g/100 g) and protein (UAE: 0.55; PEFAE: 0.42 g/100 g), had lighter color (UAE: L = 39.13; PEFAE: L = 34.72), and higher degradation temperatures (UAE: 252.68; PEFAE: 251.75 °C) than Tp-WS-NSP-CE (ash: 0.47; protein: 1.23 g/100 g; L = 34.18; < 250 °C). All Tp-WS-NSP samples contained the sugars arabinose, galactose, glucose, and mannose, had comparable functional groups in their FTIR spectra, were amorphous, and exhibited shear-thinning behavior (n < 1).     

超声辅助提取柑桔鲜皮渣果胶的工艺研究

以水为提取溶剂,研究了超声辅助提取柑桔鲜皮渣中果胶的工艺条件。与常规的浸泡提取方法比较,在酸度和物料比相同的条件下,在80℃超声处理40min柑桔鲜皮渣中的果胶,比在90℃浸泡水解1h其果胶得率提高了82.3%。在单因素实验基础上,利用二次旋转组合实验设计及响应面分析法,评价了超声功率、超声时间和提取温度对果胶得率的影响,并建立了数学回归模型。方差分析结果表明:一次项、二次项对果胶得率的影响均达到显著水平;交互项X1X2的影响极显著,X1X3、X2X3不显著。通过响应面分析法得出最佳超声提取条件:超声功率177W,提取温度71℃,超声时间49min,模型预测果胶得率为3.34%。在此超声条件下,果胶实际得率为3.32%。     

雪莲果皮多酚提取工艺及其抗氧化、抑菌活性的研究

以雪莲果皮为试验材料,以多酚提取率为指标,在单因素试验的基础上,采用正交试验法对超声辅助提取雪莲果皮多酚工艺参数进行优化,通过扫描电镜分析不同提取方式对雪莲果皮粉末表面微观形态的影响和提取得率的关系,同时评价雪莲果皮多酚的抗氧化活性及抑菌活性。结果表明最佳提取条件为:料液比1:35(g/mL)、提取温度65 ℃、乙醇体积分数40%、提取时间55 min。在此优化条件下,雪莲果皮多酚的提取率为193.87 mg/g;扫描电镜分析显示物料的破碎程度为:超声波提取法>加热回流法>浸提法>原材料粉末;抗氧化试验结果表明雪莲果皮多酚3 mg/mL浓度下对DPPH·清除能力为70.23%,IC₅₀值为0.71 mg/mL;对ABTS⁺·清除能力为97.96%,IC₅₀值为0.68 mg/mL;5 mg/mL浓度下总抗氧化能力为46.28 μmol Trolox/mL;抑菌试验结果表明雪莲果多酚对大肠杆菌和金黄色葡萄球菌均有一定的抑制作用,供试菌种的最小抑菌浓度(MIC)分别为2.5 mg/mL和0.625 mg/m...     

Bioprocessing of pineapple waste for sustainable production of bioactive compounds using solid-state fermentation

The bioprocessing of pineapple wastes into value-added bioproducts is a sustainable solution. This study examined a novel alternative for producing bioactive compounds using Aspergillus niger GH1 for solid-state fermentation (SSF) of pineapple peel and core. The results revealed that the chemical composition of pineapple waste was suitable for use in SSF. During the first 32 h of the SSF, free phenols increased by 72.31% and were positively related to antioxidant activity as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl). ß-Glucosidase and cellulase activities were increased by the SSF and were positively associated with free phenolic acids such as 5-caffeoylquinic acid. Scanning electron microscopy (SEM) confirmed mycelial invasion in pineapple waste. Analysis of free and bound phenols by high-performance liquid chromatography-mass spectrometry (HPLC-MS) showed more conjugated phenols in the unfermented than fermented waste. These results provided a broad overview of the chemical compounds with antioxidant capacity that are generated from the growth of A. niger.Industrial relevanceThe market for polyphenols and enzymes is expected to grow exponentially in the coming years. In response to this requirement and to the circular economy that seeks to take advantage of waste by generating new products, solid-state fermentation is applied, which produces in a short time polyphenols with antioxidant capacity and enzymes with possible application in the food industry from the fermentation of organic waste such as pineapple waste.     

Influence of ethanol/water ratio in ultrasound and high‐pressure/high‐temperature phenolic compound extraction from agri‐food waste

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.     

Optimisation of extraction conditions for recovering carotenoids and antioxidant capacity from Gac peel using response surface methodology

The peel of Gac fruit is regarded as waste product in the processing of Gac although it contains high level of carotenoids and possesses a significant antioxidant capacity. This study optimised the extraction yields of carotenoids and antioxidant capacity from Gac peel. Different organic solvents were examined to determine the most suitable solvent for the extraction. The extraction conditions including time, temperature and solvent–solid ratio were then optimised for maximising extraction yields of carotenoids and antioxidant capacity from Gac peel using response surface methodology. Ethyl acetate was identified as the most suitable solvent. The optimal extraction time, temperature and solvent–solid ratio were 150 min, 40.7 °C and 80 mL g^?1, respectively. The carotenoid extraction yield and the antioxidant capacity extraction yield were 271 mg/100 g DW and 737 μm TE/100 g DW, respectively. Thus, the extraction using ethyl acetate with the ratio of 80:1 (mL solvent per g Gac peel) for 150 min at 40.7 °C is suggested for recovering carotenoids and antioxidant capacity from Gac peel.     

Extraction and characterization of pectin from pomelo peel and its impact on nutritional properties of carrot jam during storage

Pectin was extracted using 0.1 N HCl at 90 °C for 120 min at pH 1.5 and 2.0 from pomelo peel and characterized in this study. Influence of various concentrations of extracted pomelo peel pectin on physicochemical, bioactive compounds, color, and sensory attributes of carrot jam during storage was also studied. Pectin extracted at pH 2.0 had higher ash content, equivalent weight, and total anhydrouronic acid content than that extracted at pH 1.0. Extracted pomelo peel pectin was categorized as high‐methoxyl pectin based on the degree of esterification. The β‐carotene and total phenol content were increased in jam after 90 days of storage. Ascorbic acid content decreased with increasing storage period. Jam prepared using commercial pectin had higher ΔE values than jam prepared using pomelo peel pectin. Physico‐chemical properties were influenced by pectin concentrations and storage time. Overall acceptability was similar for all samples on the basis of sensory evaluation. The results showed that pomelo peel might be used as a rich source of pectin and pomelo peel pectin could be used as an alternative to commercial pectins for carrot jam preparation.

Practical applications

Pectin is one of the main ingredients for jam and jelly making. Citrus fruits are main sources of pectin. Usually pomelo peels are discarded as waste materials. However, it could be a good source of pectin. In this article, pectin was extracted from pomelo peel and its application was observed as carrot jam during storage. Therefore, it can be concluded that extraction of pectin from pomelo peel might be used as an alternative to commercial pectin for carrot jam preparation.     

Lab and pilot-scale ultrasound-assisted water extraction of polyphenols from apple pomace

Apple pomace, a residue from juice or cider production, shows high content of exploitable polyphenols. In this work, apple pomace was submitted to an Ultrasound-Assisted Extraction (UAE) in order to produce extracts rich in antioxidants. After a preliminary study, a solid/liquid ratio of 150 mg of dry material per mL was used, and optimized conditions obtained by response surface methodology for polyphenols water-extraction were 40 °C, 40 min and 0.764 W/cm². A comparison showed Total Phenolics Content (TPC) obtained by UAE was 30% higher than the content obtained by Conventional Extraction (CE)(555 and 420 mg of catechin equivalent per 100 g of dry weight, respectively) and both methods presented the same extraction kinetics. Furthermore, extracts obtained by ultrasound showed higher antioxidant activity, which was confirmed by HPLC analysis, that revealed main polyphenols were not degraded under the applied conditions. The large scale experiments of this ultrasound procedure showed a potential industrial application.     

Single-step recovery of pectin and essential oil from lemon waste by ohmic heating assisted extraction/hydrodistillation: A multi-response optimization study

The main products obtained from citrus wastes are pectin and essential oil. In this work, ohmic heating assisted extraction/hydrodistillation (OHAE/H) was applied for the simultaneous recovery of pectin and essential oil from lemon waste. Optimum OHAE/H conditions to maximize the yield of pectin and essential oil were determined with response surface methodology. Three independent variables, namely liquid to solid ratio (w:v), extraction/hydrodistillation time (min) and voltage gradient (V/cm) were varied to obtain maximum pectin and essential oil yield. Optimum OHAE/H conditions were determined as 8.7:1 liquid to solid ratio, 58.4 min extraction/hydrodistillation time and 14.2 V/cm voltage gradient. The predicted pectin and essential oil yields at optimum conditions were 16.58 and 3.62 g/100 g lemon waste, respectively. Data analysis showed that all of the independent variables significantly affected the pectin and essential oil yield. In the verification study, close agreement was found between predicted and experimental values. Conventional heating extraction/hydrodistillation (CHE/H) were conducted to evaluate the effectivity of OHAE/H. With OHAE/H process, the yields of the pectin and essential oil were significantly increased when compared to CHE/H. Limonene concentration of the essential oil produced with OHAE/H was higher than the essential oil produced by CHE/H. Results demonstrate that the single-step OHAE/H could be an effective method for simultaneous extraction and hydrodistillation of pectin and essential oils.     

柠檬皮渣果胶提取预处理工艺研究

以柠檬皮渣为原料,对柠檬皮渣提取果胶工艺进行优化试验.采用四因素三水平正交试验分析方法,得出最佳工艺条件为柠檬皮渣粒度1mm、灭酶时间1 min、一级干燥温度80℃、二级干燥温度50℃,在该最优条件下,所得果胶含量为12.24％,干燥耗能为0.34 kW·h,干燥时间100 min.柠檬皮渣提取果胶的预处理工艺研究具有较高的理论价值,不仅提高了原料废弃物的综合利用率,增加了附加值和经济效益,降低了生产成本和减少环境污染,而且具有积极的经济效益和社会意义.     

Impact of long-term storage at ambient temperatures on the total quality and stability of high-pressure processed tomato juice

High-pressure processing (HPP) can produce tomato juice of high quality and safety with a short shelf life under refrigeration temperatures. Long-term higher temperature storage studies are rare and temperature tolerant products are challenging to develop. The effect of high-pressure processing (HPP) on the total quality (colour, microbial counts, phytochemical levels, antioxidant and enzymatic activities) and stability (retention over time) of tomato juice during long-term storage was investigated. Thermal processing (TP) was used as a control treatment, and overall, two different ambient conditions (20 °C and 28 °C) were tested. Immediately after processing, HPP products proved superior to TP ones (enhanced redness, total carotenoids and lycopene, stable total phenols and inactivation of pectin methyl esterase). During initial storage (30 d) most quality attributes of HPP juice remained stable. Prolonged storage, however, led to losses of most quality attributes, although HPP (20 °C) showed lower quality degradation rate constants comparison to TP and HPP (28 °C).Industrial RelevanceThere is a demand for ambient stable tomato products, especially in some parts of the world, and current industrial practices (canning, pasteurisation) either compromise in product quality or require refrigeration conditions. High-pressure processing has been investigated as milder technology, with a potential to deliver superior quality. The drawback is that is also requires chill storage. The results of this study show how quality parameters behave in a high-pressured tomato product and pave the way for further development that could optimise this technology. This could be of economic importance for the tomato juice industry to develop new products stable in ambient temperatures and perhaps beneficial for cutting down the refrigeration costs under specific conditions.