Kinetics of protein aggregate growth and breakage during isoelectric precipitation

The kinetics of isolectric precipitation of soy protein in a turbulent stirred tank reactor was studied. The effects of protein feed concentration, pH of precipitation, mean residence time, ionic strength, mixing speed, and order of addition of salt were investigated;The particle size distribution (PSD) of the solid phase was determined using a Coulter Counter Model TAII equipped with a 70 (mu)m diameter aperture tube. Protein recoveries after centrifugation and/or filtration were determined using the Kjeldahl procedure;The kinetics of solid phase formation were modelled and the results compared with the experimental PSD. The model includes growth, breakage, and outflow from the continuous reactor;Aggregate growth was described as proceeding by addition of submicron particles to a growing aggregate as a result of both Brownian and turbulent motion. The frequency of collision of colloidal particles in a turbulent fluid was combined with the definition of a linear growth rate to obtain alternative growth rate expressions dependent on particle diameter, volume fraction of primary particles, and mixer power input;Possible hydrodynamic mechanisms for particle disruption in a turbulent fluid were examined. It was shown that for the size and density of these protein aggregates the local shear mechanism predominates over the usually considered turbulent pressure fluctuations and surface erosion (due to relative motion). The aggregates breakage rate was shown to be a function of aggregate concentration and of a dimensionless Force Number (forces acting on the aggregate/forces binding the aggregate). Breakage was described as a \u27thorough\u27 process with daughter fragments smaller than the aggregate nuclei;Good fit was obtained using the proposed model and most aspects of the variation of kinetic parameters with pH, mixing speed, ionic strength, and feed concentration agreed qualitatively with the proposed mechanisms. In addition, growth rate could be related to (zeta)-potential

Valorization of Cereal Byproducts with Supercritical Technology: The Case of Corn

Ethanol and starch are the main products generated after the processing of corn via dry grinding and wet milling, respectively. Milling generates byproducts including stover, condensed distillers’ solubles, gluten meal, and the dried distillers’ grains with solubles (DDGS), which are sources of valuable compounds for industry including lignin, oil, protein, carotenoids, and phenolic compounds. This manuscript reviews the current research scenario on the valorization of corn milling byproducts with supercritical technology, as well as the processing strategies and the challenges of reaching economic feasibility. The main products recently studied were biodiesel, biogas, microcapsules, and extracts of enriched nutrients. The pretreatment of solid byproducts for further hydrolysis to produce sugar oligomers and bioactive peptides is another recent strategy offered by supercritical technology to process corn milling byproducts. The patents invented to transform corn milling byproducts include oil fractionation, extraction of undesirable flavors, and synthesis of structured lipids and fermentable sugars. Process intensification via the integration of milling with equipment that operates with supercritical fluids was suggested to reduce processing costs and to generate novel products

Estimativa da difusividade mássica efetiva do óleo essencial de cravo-da-índia (Eugenia caryophyllus) em CO2 pressurizado

O coeficiente de difusão efetivo do óleo essencial de cravo-da-índia em CO2 líquido subcrítico foi estimado. O equipamento experimental usado foi um extrator de leito fixo. O leito fixo foi formado por cravo-da-índia moído (mesh -32 + 65) e compactado, sendo assim considerado como um meio sólido. O coeficiente de difusão efetivo foi estimado pelo ajuste do perfil de concentração experimental à equação de balanço de massa em estado transiente, para difusão unidirecional em um meio sólido. A dependência do coeficiente de difusão com a concentração de óleo no sólido, foi descrita por uma função exponencial. O coeficiente de difusão determinado variou de 3,64 a 5,22x10-10m2/s. Os erros médios relativos foram menores do que 3,1%.The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65) and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%

Estimativa da difusividade mássica efetiva do óleo essencial de cravo-da-índia (Eugenia caryophyllus) em CO2 pressurizado

O coeficiente de difusão efetivo do óleo essencial de cravo-da-índia em CO2 líquido subcrítico foi estimado. O equipamento experimental usado foi um extrator de leito fixo. O leito fixo foi formado por cravo-da-índia moído (mesh -32 + 65) e compactado, sendo assim considerado como um meio sólido. O coeficiente de difusão efetivo foi estimado pelo ajuste do perfil de concentração experimental à equação de balanço de massa em estado transiente, para difusão unidirecional em um meio sólido. A dependência do coeficiente de difusão com a concentração de óleo no sólido, foi descrita por uma função exponencial. O coeficiente de difusão determinado variou de 3,64 a 5,22x10-10m2/s. Os erros médios relativos foram menores do que 3,1%.The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65) and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%

Study of the reaction between genipin and amino acids, dairy proteins, and milk to form a blue colorant ingredient

Currently, one of the biggest challenges of the colorant industry is to obtain natural blue colorants. Among the different options, a blue pigment can be formed by a crosslinking reaction between genipin and primary amine groups. However, at the industrial level, obtaining an ingredient from pure compounds, such as amino acids, is economically unfeasible. The present work aimed to study the reaction and kinetics of the blue color formation, starting the study with pure compounds (genipin and amino acids) to more complex and cheaper natural sources, such as Genipa americana L. fruits and milk. The reaction kinetics of the monomers/dimers for different amino acids reacting with genipin was evaluated, as well as the preferential amino acid, genipin:amino acid ratio and pH, to obtain the most rapid and intense blue color. Finally, the blue pigment formed using milk and its proteins was characterized by SDS-PAGE. The results suggest that the reaction kinetic is influenced by the type and concentration of the amino acid used and the pH of the medium, which could facilitate the further standardization of the industrial process. We also suggested milk as an excellent reaction medium to obtain the colorant from genipin as it presents an ideal pH and favorable amino acid composition to facilitate the reaction.Maria Isabel L. Neves thanks CAPES (001) and CAPES/PRINT (88887.572039/2020-00) for her doctoral assistantships. Maria Angela A. Meireles thanks CNPq (309825/2020-2) for her productivity grant. Alberto Valdés thanks the Ministry of Science and Innovation (MICINN) for his Juan de la Cierva-Incorporación postdoctoral grant (IJC2018-037560-I). The support from project PID2020-113050RB-I00 (MICINN, Spain) is acknowledged.Peer reviewe

Ultrasound-Assisted Extraction of Semi-Defatted Unripe Genipap (Genipa americana L.): Selective Conditions for the Recovery of Natural Colorants

Ultrasound-assisted extraction (UAE) of semi-defatted unripe genipap (SDG) using supercritical CO2 was performed to enhance the recovery of natural colorant iridoids genipin and geniposide. There are currently few natural sources of iridoids, and their application as colorants is scarce. The UAE resulted in extracts with blue and green colors using water and ethanol, respectively. The highest global yield and genipin content was recovered with water, and the geniposide was significantly recovered with ethanol. With water at 450 W, the UAE raised the maximum global yield (25.50 g/100 g raw material). At 150 W and 7 min, the maximum content of genipin (121.7 mg/g extract) and geniposide (312 mg/g extract) was recovered. The total phenolic content (TPC) and antioxidant capacity with the oxygen reactive antioxidant capacity (ORAC) assay were also high in aqueous extracts. Ethanolic extracts showed high ferric-reducing ability antioxidant potential (FRAP) values. UAE showed an efficient and fast method to obtain different extracts’ fractions from SDG, which have a wide spectrum of applications, especially as natural food colorants

Thermosonication Process Design for Recovering Bioactive Compounds from Fennel: A Comparative Study with Conventional Extraction Techniques

This study aimed to examine the impact of the combination of acoustic energy at the nominal powers of 100, 200, 300, and 400 W with moderate heat processing at 40, 50, and 60 °C on the extraction of phytochemical compounds from Foeniculum vulgare. Thermosonication processing, based on high-intensity ultrasound combined with an external heat source, can potentialize the extraction of soluble solids from plant material. However, the excessive temperature increase generated by the two energy sources during thermosonication treatment may degrade the thermolabile bioactive compounds. Regardless of the temperature condition, fennel extracts obtained at 400 W presented lower total phenolic content (TPC) than those obtained at 300 W. The cavitation heat and mechanical stress provided at 400 W may have degraded the phenolic compounds. Thereby, the best extraction condition was 300 W and 60 °C. The fennel extract presented the highest content of TPC (3670 ± 67 µg GAE/g) and antioxidant activity determined by DPPH and ABTS methods (1195 ± 16 µg TE/g and 2543.12 ± 0.00 µg TE/g, respectively) using this treatment. Thermosonication can be an innovative technique for extracting phytochemicals because it provides good results in shorter processing times, with 73% and 88% less energy consumption than Percolation and Soxhlet techniques, respectively

Perspectives on the integration of a supercritical fluid extraction plant to a sugarcane biorefinery: thermo-economical evaluation of CO2 recycle systems

Abstract In the present study, the software Aspen Plus® was used to analyse two different systems for CO2 recycle in a SFE process for extraction of more polar compounds using ethanol as co-solvent, the most common co-solvent used due to its environment-friendly nature. The extraction process of β-ecdysone from Brazilian ginseng roots was considered as example in the computational simulations. The first CO2 recycle system, named Recycle A, considered the compression of the CO2 separated in the second flash to the recycle pressure assumed at the first flash tank, its cooling to 25 °C and recirculation, while the second recycle system, named Recycle B, considered the cooling and pumping of the CO2 separated in the second flash, its heating to 25 °C and recirculation. The best techno-economic condition to operate the recycling step would be using Recycle A at 40 bar and 30 °C considering a stand-alone SFE process; and using Recycle B at 40 bar and 40 °C, considering this process in close proximity of a hypothetical sugarcane biorefinery. Therefore, these results suggest that the selection where would be located the SFE plant should be taken into account during the first steps of the process design

Biorefinery of turmeric (curcuma longa l.) using non-thermal and clean emerging technologies: an update on the curcumin recovery step

In this study, a biorefinery for the processing of turmeric (Curcuma longa L.) based on clean and emerging technologies has been proposed. High-intensity ultrasound (HIUS) technology was evaluated as a promising technique for curcumin recovery aiming to improve its extraction yield and technological properties as a colorant. In addition, we evaluated the effects of process conditions on the turmeric biomass after the extractions. The process variables were the number of stages of extraction with ethanol (1, 3 and 5) and the solvent to feed ratio (S/F) of 3, 5, 7, 9 (w/w). The highest curcumin content (41.6 g/100 g extract) was obtained using 1 wash and a S/F of 5 w/w, while the highest curcumin yield (3.9 g/100 g unflavored turmeric) was obtained using 5 stages and a S/F of 7. The extracts obtained by solid-liquid extraction assisted by HIUS showed a yellow color (157 and 169 of yellowness index) more intense than those obtained by the pressurized liquid extraction technique (101 of yellowness index) and better yield results than low-pressure solid-liquid extraction (using the same processing time). Thus, it was possible to obtain a characteristic yellow colorant with high curcumin yield in a short process time (5 min of extraction) using HIUS technology. Besides that, SEM images and FTIR spectra demonstrated that the turmeric biomasses processed by HIUS technology were not degraded101112121CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP141110/2018-0; 302423/2015-0Sem informação2015/22226-