A simple and efficient method for sinapine purification from rapeseed protein isolate effluent was developed using dynamic adsorption on Purolite C106 cation-exchange resin. Adsorption was performed at pH 4, and a flow rate of 15 BV·h−1 provided the best compromise between process productivity and dynamic binding capacity (DBC₁₀). Optimization of the elution conditions using a Design of Experiments (DoE) approach identified an optimal eluent composed of 63% (v/v) ethanol containing 0.045 M HCl. Under these conditions, sinapine was recovered with a purity of 93.41% ± 1.43% and a recovery yield of 95.99% ± 1.60%. A desorption flow rate of 60 BV·h−1 was selected to preserve both purity and recovery performance. Interestingly, the sinapine-depleted phenolic fraction exhibited the highest radical scavenging activity, surpassing that of the purified sinapine fraction and approaching the antioxidant efficiency of tocopherol in both DPPH and ABTS assays.

The design of experiments varying the pH (6-8), NaCl concentration (0-0.5 M), and temperature (20-50 degrees C) showed that the protein extractability doubled at high pH and NaCl concentration. However, the increase of temperature resulted in lower protein purity in the extract (-10%) probably due to the co-extraction of the mucilage. Concerning protein purification, the most efficient precipitation occurred at pH 4 (about 65%). The losses in proteins were primarily attributed to 2S conlinin. However, although NaCl improved the extraction yield, the presence of salt in the extract reduced the precipitation yield at pH 5-6 by 40%. The functional properties of proteins were also strongly dependent on the applied process conditions. As shown by structural analysis, precipitation at low pH led to partial denaturation of proteins, resulting in reduced solubility, notably at pH 3 (20%). However, the flaxseed isolate produced by extraction at pH 7.5 and precipitation at pH 4 exhibited an exceptionally high emulsifying capacity of 90%. Such excellent emulsification is extremely rare in plant proteins, which typically achieve 30-45% emulsifying capacity. Furthermore, the emulsion of flaxseed proteins exhibited remarkable stability for at least 20 days, and after thermal treatment.

Lactic acid bacteria are well known for hydrolyzing milk proteins, but their application to plant proteins remains limited. This study evaluated the ability of the cell-wall-anchored PrtS protease from two Streptococcus thermophilus strains to hydrolyze rapeseed albumins (RAs), aiming to generate bioactive peptides with potential food functionality. The specific activity of PrtS was first determined using a chromogenic substrate. RAs were then hydrolyzed using 10X- and 100X-concentrated cell pellets of each strain to assess the hydrolysis kinetics and the enzymatic mechanism. The results showed concentration-dependent hydrolysis, with protein conversion and the degree of hydrolysis increasing threefold at 100X for both strains. Despite the increased hydrolysis, the peptides produced had similar average sizes, averaging at five amino acids, indicating a consistent “one-by-one” cleavage mechanism. The in vitro testing of the RA hydrolysates produced with 100X PrtS from S. thermophilus LMD-9 revealed dose-dependent antioxidant activity comparable to native RAs. Importantly, unlike native RAs, these hydrolysates did not induce increased secretion of the pro-inflammatory mediator IL-8 in inflamed HT-29 cells, suggesting a reduced pro-inflammatory potential. These findings demonstrate that PrtS protease from S. thermophilus can effectively hydrolyze rapeseed proteins to produce functional hydrolysates with improved bioactivity profiles. Such hydrolysates have promising applications as functional ingredients in plant-based food products, contributing both to health benefits and potential food preservation through antioxidant activity.

Sinapine adsorption was studied on four weak cation exchanges at pHs ranging from 2 to 8. The best adsorption rate was observed with C106 resin at pH 4 (95.25%). The adsorption kinetics followed a pseudo-second-order model while the isotherm data better fitted the Langmuir model. The ΔG°, ΔH°, and ΔS° values (−25.834 kJ·mol−1, −24.428 kJ·mol−1, and 0.004 kJ·mol−1·K−1) revealed that the adsorption process was spontaneous and exothermic. Acidified ethanol showed a better desorption rate (75.41%), while virtually no (3.32%) or low (31.14%) sinapine desorption was observed with 50% ethanol and 0.1 M HCl solution, respectively. This indicated that sinapine adsorption took place throughout both ionic and hydrophobic interactions. Very close sinapine adsorption performances were observed with an effluent of the patented rapeseed protein isolate process. Two-step desorption using 50% ethanol, then acidified ethanol, yielded a highly purified neutral sinapine-derivative phenol fraction (75.23%) in the first elution fraction and sinapine (98.85%) in the second one.

An optimized proteolysis process was applied to rapeseed meal proteins (RP) and the hydrolysate was separated by membrane filtration allowing the production of highly metal-chelating peptides in the permeate. In order to identify the chemical structure of the most active obtained metal-chelating peptides, immobilized metal affinity chromatography (IMAC) was applied. The RP-IMAC peptide fraction was mainly composed of small peptides from 2 to 20 amino acids. Using the Ferrozine assay, RP-IMAC peptides showed a significant chelating efficiency higher than sodium citrate and close to that of EDTA. The peptide sequences were identified by UHPLC-MS and several possible iron binding sites were found. β-carotene oxidation assay and lipid oxidation in bulk oils or emulsion were carried out to evaluate the potential of such peptides as efficient antioxidants to protect lipids from oxidation. While chelating peptides showed a limited efficiency in bulk oil, they performed more efficiently in emulsion.

Preventing lipid oxidation and microbial spoilage are both major concerns in sectors such as food and cosmetic industries. Biopeptides, arouse great interest to substitute synthetic antioxidants. Some plant proteins, like 2S rapeseed albumins are known presenting antimicrobial properties. In this context, we aimed to valorize total rapeseed meal proteins with controlled enzymatic proteolysis to generate mineral chelating peptides from the 11S globulins fraction while keeping intact the albumins fraction. To do so, screening of proteases on total rapeseed protein isolate was implemented highlighting a globulin-selective hydrolysis with Prolyve®. Ultrafiltration was then used to purified albumins and enrich the peptide fraction. The fraction obtained showed a noteworthy metal chelating activity. Then, the selected proteolysis was optimized in order to maximize the albumins purity and yield. For that, enzymatic mechanism identification in a wide operating conditions area was led to define the DoE. Then, simulation of hydrolysis kinetics was driven to predict protein fractions concentration at any time and any set of operation conditions. The obtained models were implemented in a genetic-evolutionary algorithm to generate the Pareto Front and Domain, presenting the targeted economical compromises. One solution was chosen and the identified corresponding operating conditions proved the metal chelating activity conservation (EC50 = 247 ± 27 µg) for three times faster production at the same enzyme cost. Finally, peptide activity was investigated in oil-in-water emulsion systems and compared with EDTA. Results showed that peptides could be as effective as EDTA to avoid primary and secondary lipid oxidation products formation.This work demonstrates an original total valorization of both rapeseed meal proteins in food applications. First, antioxidant peptides produced from the globulin fraction, could be used as food preservative in oil-in-water emulsion systems, but also as preventing agents for micronutrient deficiencies. And, the purified albumin fraction could be used to prevent microbial spoilage.

This article proposes the application of multiobjective decision making strategy for selective albumin extraction by Pareto's domain determination and ranking by Decision Engineering tool based on the Rough Set approach. In this study, both competing process performance indicators of rapeseed albumin extraction and quality of the solid residue remaining from this process were considered for an overall valorization of the rapeseed cold-pressed meal. The impact of extraction pH and NaCl concentration on three process performance indi-cators including the albumin extraction yield, the albumin content in the extract, and the phytic acid content in the remaining solid residue was studied. The results of the opti-mization approach showed that the high selectivity of rapeseed albumin extraction was to the detriment of the productivity of the process and the quality of the solid residue. The optimal conditions for selective rapeseed albumin extraction while producing a high-quality solid residue were identified at pH 2.0 and 0.11 mol L-1 of NaCl concentration. Upon these conditions, good albumin extraction yield was achieved (55.5%) with a high selectivity (97.9% of albumins in the extract). The isolate obtained after purification exhibited suitable color, high solubility, promising emulsifying properties and good foaming properties, which is of interest for food applications. Besides, the identifying extraction conditions yielded a protein-rich solid residue (35.6% on dry matter basis) with reduced phytic acid content (3.6% on dry matter basis), which can be used for feed applications. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Preventing oxidation and microbial spoilage are both major concerns in food industries. In this context, this study aimed to valorize the total rapeseed meal proteins with controlled enzymatic proteolysis to generate potent mineral-chelating peptides from cruciferins while keeping intact the antimicrobial napins. Implementation of proteolysis of total rapeseed protein isolate with the Prolyve® enzyme highlighted an interesting selective hydrolysis of the cruciferins. Hence, the mechanism of this particular hydrolysis was investigated through a Design of Experiments method to obtain a model for the prediction of kinetics (cruciferin degradation and napin purity) according to the operating conditions applied. Then, multicriteria optimization was implemented to maximize the napin purity and yield while minimizing both enzymatic cost and reaction time. Antioxidant assays of the peptide fraction obtained under the optimal conditions proved the high metal-chelating activity preservation (EC50 = 247 ± 27 µg) for more than three times faster production. This fraction might counteract lipid oxidation or serve as preventing agents for micronutrient deficiencies, and the resulting purified napins may have applications in food safety against microbial contamination. These results can greatly help the development of rapeseed meal applications in food industries.

The fractionation of the aqueous effluent of Aucoumea klaineana Pierre (Okoume) sapwood steam explosion was examined by a sequential-dilution type membrane diafiltration. The permeate and retentate fractions were characterized by HPLC-SEC, HSQC-NMR, FTIR, UV-visible and HPAE-PAD ion chromatography. Diafiltration with 10 kDa regenerated cellulose membrane has been shown to provide efficient fractionation without fouling. O-2 and/or O-3 acetylated xylans with a lower proportion of O2 and/or O-3 acetylated glucomannans were isolated in the retentate (approximate to 35% w/w and 1.08 w/w% based on initial effluent solid content and on initial dry wood respectively, including 65% w/w in the range 9-22 kDa). The molecular weights of the polysaccharides were significantly higher than those obtained by ethanolic precipitation. The permeate concentrated low molecular mass oligomers (90% w/w < 2.3 kDa, 1.88 w/w% based on initial dry wood) composed of pectic sugars, highly acetylated xylans (DS approximate to 0.9) and relatively high proportion of soluble lignin (approximate to 40% w/w) including Lignin-Carbohydrate Complexes (LCCs).

The aim of this study was to valorize liquid effluent from the sunflower protein isolate process by extracting phenolic compounds it contains. To do so, XAD7 resin was used. A multicriteria optimization methodology based on design of experiments showed the optimal conditions were adsorption flow rate of 15 BV/h at pH 2.7, a desorption flow rate at 120 BV/h with ethanol/water 50% (v/v). The best trade-off between purity and recovery yields resulted in the production of a fraction containing 76.05% of chlorogenic acid (CGA) whose biological properties were evaluated. DPPH and ABTS tests showed that this fraction had a higher radical scavenging capacity than vitamin C. In vitro assays have shown that this fraction, when used at a concentration corresponding to 50 or 100 µM of CGA, does not present any cytotoxicity on human THP-1 cells differentiated into macrophages. In addition, this fraction when added prior to the inflammatory stimulus (LPS) can reduce tumor necrosis factor-alpha (TNF-α) production by 22%, thereby highlighting its protective properties against future inflammation.

Exploitation of plant proteins as an alternative to animal proteins currently presents an important challenge for food industries. In this contribution, total sunflower protein isolate from cold press meal was used as a starting material for the generation of highly soluble and functional hydrolysates that could be used in various food formulations. To do this, a rational and complete approach of controlled hydrolysis was implemented using the individual Alcalase and Prolyve enzymes. The method of stopping the hydrolysis reaction was also evaluated. The influence of operating conditions on hydrolysis kinetics and enzymatic mechanism was studied to identify the appropriate hydrolysis conditions. The gain of the solubility was then analyzed and compared to that of the initial proteins. Finally, the emulsifying and foaming properties (capacities and stabilities) of the resulting hydrolysates were also assessed. As a result, controlled enzymatic proteolysis significantly improved the sunflower protein solubility at neutral pH (twofold increase) and generated highly soluble hydrolysates. The limited proteolysis also maintained the good foam capacities and allowed an improvement in the initial foam stabilities and emulsifying capacities and stabilities of sunflower proteins. This contribution can greatly increase the value of sunflower meal and help in the development of sunflower protein products in the future.

In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry.

In this study, adsorption of phenolic compounds from an aqueous by-product of sunflower protein isolate production was investigated. Phenolic compounds in this by-product (ultrafiltration permeate of protein purification step) were almost exclusively CGA (mainly 5-CQA isomer). Five different macroporous resins including XAD4, XAD7, XAD16, XAD1180, and HP20 were screened for CGA capture. XAD16 had the best massic adsorption capacities (15.32 ± 0.04 mg/g), while XAD7 had a better surface adsorption capacity (0.027 ± 0.00146 mg/m²). CGA adsorption on both resins followed the pseudo-second-order kinetic model with a similar intra diffusional pattern. Adsorption isotherms of the two resins better fitted the Langmuir model with Qmax for XAD7 and XAD16 of 0.054 and 0.040 (mg/m²), respectively. The adsorption process of phenolic compounds revealed to be exothermic, physical adsorption, and spontaneous. Better adsorption results were observed at 25°C. Maximal CGA desorption ratio was observed from 70% (v/v) ethanol. The high values were reached with both the resins (88.09 ± 0.13 and 86.16 ± 0.32% for XAD7 and XAD16, respectively). The CGA purity in the desorption phase was surprisingly high (77.56 ± 0.99% and 74.59 ± 0.12% for XAD7 and XAD16, respectively).

The method described in the article aims at the quantification of both main storage proteins, globulins and albumins, in aqueous extract from rapeseed, as an alternative to the current reference methods, Kjeldahl and SDS-PAGE electrophoresis. The new method lies on the analytical separation of extracted compounds by Size-Exclusion High Performance Liquid Chromatography (SE-HPLC) (Biosep-SEC-s2000, 5 mu m). The elution of rapeseed extracts with water/acetonitrile/trifluoroacetic acid (45/55/0.1% v/v) during 30 min yields two distinct peaks for the main proteins of rapeseed. Based on the protein extinction coefficients, a calibrationless methodology was developed for their quantification on the basis of the UV signal. The SE-HPLC method was successfully compared to references: Kjeldahl and SDS-PAGE densitometry for the determination of the proportion of each protein. Then, it was successfully applied on two other oleoproteagineous plants, linseed and sunflower.

This article proposes an alternative extraction strategy for the valorization of the sunflower meal leading to the production of an albumin isolate for human nutrition and a valuable residual meal for feed application. For this purpose, a response surface methodology was employed to study the effect of pH (3–6) and NaCl (0–0.5 mol.L−1) on albumin extraction (yield, content, and phenolic contamination). Total phytate and nitrogen content in residual meal were also considered. As a result, the significant influence (p-value<0.05) of both pH and NaCl concentration on investigated responses was demonstrated. The analysis of regression and variance confirmed a high accuracy of developed models for process prediction. Based on generated equations, a multi-objective optimization was applied for simultaneous maximization of albumin extraction performances and the residual meal value. The best trade-off for sunflower albumin extraction was found at pH 4.1 and 0.25 mol.L−1 of NaCl concentration. Under this condition, good albumin recovery was achieved (>70%), whereas extract was enriched in sunflower albumin fraction (>90% of total proteins) and phenolic contamination of albumins was considerably reduced (<1.6 mg of covalently bound chlorogenic acid per gram of proteins). The selected condition produced value-added residual meal with low phytate level (<4% on dry matter basis) and high protein content (>40% on dry matter basis). Further purification of sunflower albumins yielded a white color product characterized by excellent solubility (approximately 100% at pH 2–11), stable conformation of structure against pH and temperature, and beneficial functional properties (foaming and emulsifying).

The presence of aminoacylase activities was investigated in a crude extract of Streptomyces ambofaciens ATCC23877. First activities catalyzing the hydrolysis of N-alpha or epsilon-acetyl-L-lysine were identified. Furthermore, the acylation of lysine and different peptides was studied and compared with results obtained with lipase B of Candida antarctica (CALB). Different regioselectivities were demonstrated for the two classes of enzymes. CALB was able to catalyze acylation only on the epsilon-position whereas the crude extract from S. ambofaciens possessed the rare ability to catalyze the N-acylation on the alpha-position of the lysine or of the amino-acid in N-terminal position of peptides. Two genes, SAM23877_1485 and SAM23877_1734, were identified in the genome of Streptomyces ambofaciens ATCC23877 whose products show similarities with the previously identified aminoacylases from Streptomyces mobaraensis. The proteins encoded by these two genes were responsible for the major aminoacylase hydrolytic activities. Furthermore, we show that the hydrolysis of N-alpha-acetyl-L-lysine could be attributed to the product of SAM23877_1734 gene.

The purpose of this study was to improve two common assays used for antioxidant capacity measurements, i.e. the reducing power and chelating ability measurements, for appropriate comparisons between the molecules tested and chosen references, as the usual methods are often performed in a qualitative way rather than a quantitative way. After revision, it was then possible to determine an AERC index (Ascorbate Equivalent Reducing Capacity) and a CECC (Carnosine Equivalent Chelating Capacity) or EECC (EDTA Equivalent Chelating Capacity) index according to the chosen standard, by analogy to the TEAC indice (Trolox Equivalent Antioxidant Capacity) already used in many reported works to determine the free radical scavenging activity. Thus, the determination of these relative indices enables the comparison of antioxidative capacities obtained in various studies. The adaptation of these two assays to micro-scales and the calculation of AERC, EECC and CECC were performed on model peptides.

The purpose of this study was to improve two common tests used for antioxidant capacity measurements, i.e. the reducing power and chelating ability measurements, for appropriate comparisons between the molecules tested and chosen references, as the usual methods are often performed in a qualitative way rather than a quantitative way. After revision, it was then possible to determine an AERC indice (Ascorbate Equivalent Reducing Capacity) and a CECC (Carnosine Equivalent Chelating Capacity) or EECC (EDTA Equivalent Chelating Capacity) indice according to the standard chosen, by analogy to the TEAC indice (Trolox Equivalent Antioxidant Capacity) already used in many reported works to determine the free radical scavenging activity. Thus, the determination of these relative indices enables the comparison of antioxidative capacities obtained in various studies. The adaptation of these two tests to micro-scales and the calculation of AERC, EECC and CECC were performed on model peptides.