Sustainable sunflower processing — II. Recovery of phenolic compounds as a by-product of sunflower protein extraction

Ultrasonic treatment as a modern technique to facilitate the extraction of phenolic compounds from organic sunflower seed cakes

BACKGROUND

Three different organic sunflower seed cakes, produced from seeds differing in the content of their hulls, were extracted by two different extraction methods - conventional extraction (CE) and ultrasound-assisted extraction (UAE). The total phenolic compound (TPC) content of the extracts was evaluated using Folin-Ciocâlteu reagent (FCR) and high-performance liquid chromatography (HPLC). The antioxidant capacity of extracts was evaluated with the Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays.

RESULTS

The results showed that both extracts displayed high TPC content and antioxidant capacity. The UAE method showed significantly higher TPC content and antioxidant capacity values than CE. Individual phenolic compounds such as chlorogenic acid (CGA) isomers (3-, 4- and 5-O-caffeoylquinic acids), di-CGA isomers, and feruloylquinic and coumaroylquinic acids were identified according to their exact masses by HPLC coupled to time-of-flight mass spectrometry.

CONCLUSION

The results revealed that the UAE method could be used effectively to facilitate the extraction of phenolic compounds from sunflower seed cake. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ultrasound-assisted macroporous resin treatment improves the color and functional properties of sunflower meal protein

Sunflower meal protein (SMP) has been considered as a high-quality source of plant protein. However, because the chlorogenic acid (CA) contained in sunflower seed meal was prone to oxidation reactions under traditional alkali extraction conditions, the extracted protein has a dark color and some poor functional properties. To this end, this study used ultrasound-assisted macroporous resin treatment to extract SMP. The improvement effects and potential mechanisms of ultrasonic-assisted macroporous resin treatment with different powers (100, 300, and 500 W) on the color and functional properties of SMP were studied. The results showed that compared with untreated sunflower meal protein (USMP), the lightness value (L*), solubility, emulsification, and gel elasticity were significantly enhanced when treated with 100 W and 300 W ultrasonic-assisted macroporous resin. However, when the ultrasonic power was increased to 500 W, the L* value, solubility, emulsification, and gel elasticity decreased instead, indicating that lower power (100 W and 300 W) ultrasonic-assisted macroporous resin treatment significantly improved the color and functional properties of SMP. Further research found that ultrasound-assisted macroporous resin treatment changed the secondary and tertiary structures of SMP, transformed β-sheet into α-helix and β-turn through rearrangement, and significantly improved surface hydrophobicity. It shows that ultrasonic-assisted macroporous resin treatment expands the SMP structure and exposes hydrophobic groups, thereby improving the color and functional properties of SMP. This study provides a potential strategy for extracting SMP with light color and good functional properties. It also provides a theoretical basis for the wide application of SMP in food processing.

Turning Food Protein Waste into Sustainable Technologies

For each kilogram of food protein wasted, between 15 and 750 kg of CO₂ end up in the atmosphere. With this alarming carbon footprint, food protein waste not only contributes to climate change but also significantly impacts other environmental boundaries, such as nitrogen and phosphorus cycles, global freshwater use, change in land composition, chemical pollution, and biodiversity loss. This contrasts sharply with both the high nutritional value of proteins, as well as their unique chemical and physical versatility, which enable their use in new materials and innovative technologies. In this review, we discuss how food protein waste can be efficiently valorized not only by reintroduction into the food chain supply but also as a template for the development of sustainable technologies by allowing it to exit the food-value chain, thus alleviating some of the most urgent global challenges. We showcase three technologies of immediate significance and environmental impact: biodegradable plastics, water purification, and renewable energy. We discuss, by carefully reviewing the current state of the art, how proteins extracted from food waste can be valorized into key players to facilitate these technologies. We furthermore support analysis of the extant literature by original life cycle assessment (LCA) examples run ad hoc on both plant and animal waste proteins in the context of the technologies considered, and against realistic benchmarks, to quantitatively demonstrate their efficacy and potential. We finally conclude the review with an outlook on how such a comprehensive management of food protein waste is anticipated to transform its carbon footprint from positive to negative and, more generally, have a favorable impact on several other important planetary boundaries.

Metabolomic analysis and ecofriendly enrichment of sunflower meal extract

BACKGROUND

The presence of phenolic compounds in sunflower is well reported in the literature; however, knowledge is scarce when it comes to the composition of other secondary metabolites in this species and their by-products. This work evaluated, for the first time, the phytochemical composition of sunflower meal produced in Brazil. A combination of mixture design and central composite rotatable design 2³ models was then applied to maximize the recovery of bioactive compounds using ecologically friendly solvents and concentrating by applying activated carbon, a sustainable adsorbent. The product of this extraction-concentration was also evaluated by an untargeted metabolomic approach using ultra-performance liquid chromatography coupled to mass spectrometry.

RESULTS

A diverse and abundant profile of phenolic compounds was obtained from Brazilian sunflower meal: in total, 51 natural products were tentatively identified, 35 of which for the first time in sunflower. The sorption capacity of the activated charcoal, in the optimized process conditions, was effective in the separation and concentration of minority secondary metabolites. The ecofriendly extract proved to be enriched in plumberoside, p-coumaric acid, and alkaloids.

CONCLUSIONS

Investigation of the phytochemical profile of sunflower meal produced in Brazil pointed to several secondary metabolites reported for the first time in sunflower samples, including phenolic compounds, alkaloids, and terpenes. The use of activated charcoal in an alkaline medium as an adsorbent for the concentration of these phytochemicals, from an aqueous extract, generated a potentially cost-effective, ecofriendly extract, enriched in minor metabolites, indicating a possible innovative way to selectively obtain these compounds from sunflower meal. © 2022 Society of Chemical Industry.

Identification and Capture of Phenolic Compounds from a Rapeseed Meal Protein Isolate Production Process By-Product by Macroporous Resin and Valorization Their Antioxidant Properties

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.

Sunflower seed byproduct and its fractions for food application: An attempt to improve the sustainability of the oil process

The sunflower (Helianthus annus L.) is one of the main oil crops in the world grown for the production of edible and biodiesel oil. Byproducts of the extraction of sunflower oil constitute a raw material with potential for several applications in the food area due to its chemical composition, including the high content of proteins and phenolic compounds. Thoughtful of a consumer increasingly concerned with the environmental impact, we try to clarify in this review the potential of using sunflower seed byproducts and their fractions to enhance the production of potentially functional foods. The applications of sunflower seed byproduct include its transformation into flours/ingredients that are capable of improving the nutritional and functional value of foods. In addition, the protein isolates obtained from sunflower seed byproduct have good technological properties and improve the nutritional value of food products. These protein isolates can be used to obtain protein hydrolysates with technological and bioactive properties and as matrices for the development of edible, biodegradable, and active films for food. The sunflower seed byproduct is also a source of phenolic compounds with bioactive properties, mainly chlorogenic acid, which can be extracted by different methods and applied in the development of functional foods and active and bioactive food packaging. The use of sunflower seed byproduct and its fractions are promising ingredients for the development of healthier and less expensive foods as well as the alternative to decrease the environmental problems caused by the sunflower oil industry.

Multicriteria Optimization of Phenolic Compounds Capture from a Sunflower Protein Isolate Production Process by-Product by Adsorption Column and Assessment of Their Antioxidant and Anti-Inflammatory Effects

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.

A review on protein extracts from sunflower cake: techno-functional properties and promising modification methods

De-oiled sunflower cake is a sustainable and promising protein source with high phenolic and fiber contents. The cake, which is an industrial by-product has been the subject of many studies investigating various aspects such as protein extraction, functional properties, interaction with other ingredients, and its performance in a wide range of food products. Innovative and conventional techniques of protein extraction from sunflower cake have been investigated to increase extraction yield and improve desired functional characteristics. Modulation of structure of plant-based proteins helps to control their techno-functional properties and widen their applications. Structure modification of proteins by physical methods including ultrasound treatment and gamma irradiation as well as enzymatic and chemical methods has been used to improve the functional properties of sunflower protein. This review collects and critically discusses the available information on techno-functional properties of protein extracts from sunflower cake and how its techno-functional properties can be tailored using various structure modification methods.

A new SE-HPLC method for simultaneous quantification of proteins and main phenolic compounds from sunflower meal aqueous extracts

The aim of this research was to develop a method for simultaneous quantification of proteins and main polyphenolic compounds extracted from oleaginous meal by aqueous media. Size exclusion chromatography with a Biosep column (exclusion range from 1 to 300 kDa) and acetonitrile/water/formic acid (10:89.9:0.1 v/v) eluent at 0.6 mL min^-1 yielded the most efficient separation of sunflower proteins and chlorogenic acid monoisomers (3-caffeoylquinic acid, 5-caffeoylquinic acid, and 4-caffeoylquinic acid). After a study of the stability of the extract components, the incorporation of a stabilization buffer (0.5 mol L^-1 tris(hydroxymethyl)aminomethane-hydrochloric acid/1.0 mol L^-1 sodium chloride at pH 7) was proposed to avoid polyphenol-protein interactions and/or isomeric transformation. The use of 214 nm as the wavelength for protein quantification was also included to minimize the effect of interference from polyphenol-protein interactions on the quantification. Under the used experimental conditions, the protein and chlorogenic acid monoisomer signals remained stable during 300 min at 20 °C (95-125% of the starting value). The developed method was validated and parameters such as specificity, sensitivity, precision, and accuracy were determined. The results from size exclusion chromatography correlated well with the results of protein determination by the reference Kjeldahl method. The proposed method was successfully applied for rapeseed extract analysis making simultaneous quantification of proteins and major rapeseed polyphenols (sinapine and sinapic acid) possible. Graphical abstract.

Simultaneous decoloration and purification of crude oligosaccharides from pumpkin (Cucurbita moschata Duch) by macroporous adsorbent resin

This study investigated an efficient and recyclable approach for purification of crude pumpkin oligosaccharide (POS) by macroporous resins. Five resins with different physical and chemical properties were tested for decoloration of POS. In virtue of its higher decoloration ratio (92.6%) and POS recovery ratio (81.3%), the macroporous resin DM28 was considered to a better selection. Depending on the changes of molecular weight, part of the monosaccharides in crude POS were removed simultaneously after decoloration by DM28. Operating conditions were also determined by the dynamic breakthrough and desorption curves. Moreover, UV/vis spectroscopy and Fourier transform infrared results revealed that most of the colored impurities and proteins can be removed, but the characteristic groups of the POS exhibited no significant difference. Compared with traditional methods, DM28 resin is superior in decoloration efficiency, pigment recovery and oligosaccharide recovery. This research contributes to further exploration on the structure and function of POS.