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Pulsed electric fields (PEF) have been reported to increase the total oil extraction yield (OEYTOTAL) of fresh pecan nuts maintaining oil characteristics and increasing phenolic compounds in the remaining by-product. However, there is no information regarding the PEF effect on dry pecan nuts. Dry kernels were pretreated at three specific energy inputs (0.8, 7.8 and 15.0 kJ/kg) and compared against untreated kernels and kernels soaked at 3, 20 and 35 min. OEYTOTAL, kernels microstructure, oil stability (acidity, antioxidant capacity (AC), oil stability index, phytosterols and lipoxygenase activity), along with by-products phenolic compounds (total phenolics (TP), condensed tannins (CT)) and AC were evaluated. Untreated kernels yielded 88.7 ± 3.0%, whereas OEYTOTAL of soaked and PEF-treated kernels were 76.5-83.0 and 79.8-85.0%, respectively. Kernels microstructural analysis evidenced that the 0.8 kJ/kg pretreatment induced oleosomes fusion, while no differences were observed in the stability of extracted oils. PEF applied at 0.8 kJ/kg also increased by-products CT by 27.0-43.5% and AC by 21.8-24.3% compared to soaked and untreated kernels. These results showed that PEF does not improve OEYTOTAL when it is applied to dry pecan nuts, demonstrating that kernels' moisture, oil content and microstructure play an important role in the effectiveness of PEF.

RESUMO

Multi-response optimization of hot pressurized liquid extraction (HPLE) was applied for the first time to obtain maqui (Aristotelia chilensis [Mol.] Stuntz) leaf extracts. The total polyphenol content (TPC), the antioxidant capacity (AC) as well as the total polyphenol purity of the maqui leaf extracts were accurately predicted (RSD < 8%) at the evaluated extraction scales. The optimum HPLE conditions that prioritized TPC and AC equally (OPT1) recovered ~3 times more TPC (205.14 mg GAE/g leaves) than maqui leaf extracts obtained by maceration, while the extract that prioritized purity over TPC and AC presented the highest purity (36.29%) and an EC50 ~3 times lower than currently reported values. It was found by multi-response optimization that maqui leaves and HPLE are among the best natural sources and extraction techniques, respectively, to recover protocatechuic acid, quercetin, and catechin.

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Vegetable-based proteins may be extracted from different sources using different extraction methods, among them, ultrasound-assisted extraction stands out. This review presents the current knowledge on ultrasound-assisted extraction (UAE) and the functional properties of extracted vegetable proteins. Ultrasound generates cavitation in a liquid medium, defined as gas and vapor microbubbles collapse under pressure changes large enough to separate them in the medium. Cavitation facilitates the solvent and solid interaction, increasing yield and reducing extraction periods and temperature used. Moreover, ultrasound treatment changed extracted protein properties such as solubility, hydrophobicity, emulsifying and foam, water and oil absorption capacity, viscosity, and gelatinization. Ultrasound-assisted extraction is a promising technique for the food technology sector, presenting low environmental impact, lower energy and solvent consumption, and it is in accordance with green chemistry technology and sustainable concepts.

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Alkaline hydrolysis of chromium-tanned leather wastes (CTLW) is a well-known process that allows the extraction of its most valuable portion: the protein. However, alkaline hydrolysis is time-consuming. It usually takes from 2 to 10 h to be completed. In this work, alkaline hydrolysis was performed in a steam explosion reactor, using CaO as the alkalinizing agent and aiming at a short-time process. Three different temperatures and residence times were tested: 130, 140, and 150°C; 5, 10, and 15 min. When performed at 140°C for 10 min, the steam explosion in alkaline medium resulted in the optimum combination of protein extraction yield (30%) and gelatine quality (viscosity of 2.4 cP at 25°C in a 24.6 g/L protein solution - 39 kDa of molecular mass [Formula: see text]w). Not only a high extraction yield was achieved, but when compared to traditional methods, steam explosion in alkaline medium reduced the process time by a factor that varied from 12 to 36 times. It also reduced chromium content in the gelatine by a factor that varied from 16 to 96 times. Finally, to produce a high quality product, the ash content of the gelatine was reduced from 11.8% (dry basis) to 1.2% (dry basis) through diafiltration. This purification allows the application of the gelatine, for example, in the production of polymeric films.

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This work aims at characterizing linseed oil obtained using different extraction methods (hexane, subcritical propane and pressurized ethanol), and comparing the results with commercial linseed oil extracted by cold mechanical press method. An experimental design helped to evaluate temperature and pressure effects on the oil extraction using propane and ethanol. Gas chromatography assisted in evaluating the essential fatty acids. There were no significant differences among the ω-3, 6 and 9 fatty acids from linseed oil obtained using the different extraction methods. Only the acidity of linseed oil extracted by subcritical propane (0.956%) showed significant differences among the physicochemical parameters. Extraction using organic solvent (Soxhlet) gave a 36.12% yield. Extraction using subcritical propane at 107 Pa and 40 °C for 1.5 h gave a better yield (28.39%) than pressurized ethanol (8.05%) under similar conditions. Linseed oil extraction using subcritical propane was economically viable, resulting in a 124.58 US$/L product cost. The results present subcritical propane extraction as a promising alternative for obtaining linseed oil at mild temperature and pressure conditions, without losing quality and quantity of fatty acids such as ω-3, 6 and 9.

RESUMO

BACKGROUND: Chia mucilage has potential application as a functional ingredient; advances on maximizing its extraction yield could represent a significant technological and economic impact for the food industry. Thus, first, the effect of mechanical agitation time (1-3 h) on the exudation of chia mucilage was analyzed. Then, response surface methodology was used to determine the optimal combination of the independent variables temperature (15-85 °C) and seed: water ratio (1: 12-1: 40.8 w/v) for the 2 h exudation that give maximum chia mucilage yield. Experiments were designed according to central composite rotatable design. RESULTS: A second-order polynomial model predicted the variation in extraction mucilage yield with the variables temperature and seed: water ratio. The optimal operating conditions were found to be temperature 85 °C and a seed: water ratio of 1: 31 (w/v), reaching an experimental extraction yield of 116 ± 0.21 g kg-1 (dry basis). The mucilage obtained exhibited good functional properties, mainly in terms of water-holding capacity, emulsifying activity, and emulsion stability. CONCLUSION: The results obtained show that temperature, seed: water ratio, and exudation time are important variables of the process that affect the extraction yield and the quality of the chia mucilage, determined according to its physicochemical and functional properties. © 2018 Society of Chemical Industry.

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La presente investigación tuvo como propósito evaluar el rendimiento y las características de la pectina extraída enzimáticamente a partir de la cáscara, pericarpio del fruto de cacao (Theobroma cacao L.); para ello, se realizó un diseño de tipo unifactorial, con 4 niveles de tratamiento, variando la concentración de complejo enzimático comercial Viscozyme L., de la marca Novozyme®. La pectina obtenida fue caracterizada, de acuerdo a la metodología planteada por Owens et al. 1952. Se elaboró un producto comercial tipo conserva (mermelada), donde se comparó la pectina obtenida enzimáticamente, con pectina comercial de alto y bajo metoxilo; en ambos casos fue evaluada la viscosidad aparente del fluido obtenido. Como resultados, se obtuvo mayor rendimiento de extracción de pectina promedio (13,0±0,53%), utilizando la mayor concentración de complejo enzimático (82,9 µL/100g cáscara), presentando diferencias significativas con los demás tratamientos (p<0,05); el porcentaje de metóxilo (ME) fue de 1,58±0,01%, el peso equivalente (PE) 5091,4±77,6 mg/meq; la acidez libre (AL) 0,20±0,01meq/g; el grado de esterificación (GE) 72±0,1% y el porcentaje de ácido anhídridogalacturónico (AAG) 12,5±1,0%. Con respecto al producto comercial, se observaron características reológicas de un fluido no Newtoniano pseudoplástico, con una viscosidad aparente máxima de 6043,7 mPa.s y mínima de 1741,3 mPa.s, al aumentar la fuerza del torque, presentando una menor capacidad viscosante que la pectina comercial. De acuerdo a los resultados obtenidos, se demostró que existe la oportunidad de obtener pectinas a partir de residuos del sector cacaotero, utilizando enzimas comerciales, con posibles usos en la industria alimentaria.

This research was aimed to evaluate the yield and characteristics of pectin extracted enzymatically from cocoa (Theobroma cacao L.) pod husks pericarp. For this a unifactorial type design with 4 levels of treatment varying the concentration of commercial enzyme complex Viscozyme L. of the brand Novozyme®.. The obtained pectin was characterized according to the methodology proposed by Owens et al. 1952. A commercial preserved product (jam) was elaborated, where pectin obtained enzymatically was compared with high and low methoxyl commercial pectin, in both cases the apparent viscosity of the obtained fluid was evaluated. The highest pectin extraction yield (13.0 ± 0.53%) was obtained using the highest concentration of enzyme complex (82.9 µL / 100g shell), showing significant differences with the other treatments (p <0,05). Percentage of methoxyl (ME) was 1.58 ± 0.01%, equivalent weight (PE) 5091.4 ± 77.6mg/meq, free acidity (AL) 0.20 ± 0.01meq/g, degree of Esterification (GE) 72 ± 0.1% and the percentage of anhydridogalacturonic acid (AAG) 12.5 ± 1.0%. With respect to the commercial product, rheological characteristics of a pseudoplastic non-Newtonian fluid with a maximum apparent viscosity of 6043,7 mPa.s and a minimum of 1741,3 mPa.s were observed when increasing the torque force, presenting a lower viscosity capacity than the commercial pectin. According to the results obtained it was demonstrated that there is an opportunity to obtain pectins from residues from the cocoa sector using commercial enzymes with possible uses in the food industry.