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

Comprehensive review of composition distribution and advances in profiling of phenolic compounds in oilseeds

A wide range of phenolic compounds participate in oilseed growth, regulate oxidative stability of corresponding vegetable oil, and serve as important minor food components with health-promoting effects. Composition distribution of phenolic compounds varied in oilseeds. Isoflavones, sinapic acid derivatives, catechin and epicatechin, phenolic alcohols, chlorogenic acid, and lignans were the main phenolic compounds in soybean, rapeseed, peanut skin, olive, sunflower seed, sesame and flaxseed, respectively. Among which, the total isoflavones content in soybean seeds reached from 1,431 to 2,130 mg/100 g; the main phenolic compound in rapeseed was sinapine, representing 70–90%; chlorogenic acid as the predominant phenolic compound in sunflower kernels, represented around 77% of the total phenolic content. With the rapid development of analytical techniques, it is becoming possible for the comprehensive profiling of these phenolic compounds from oilseeds. This review aims to provide recently developments about the composition distribution of phenolic compounds in common oilseeds, advanced technologies for profiling of phenolic compounds by the metabolomics approaches based on mass spectrometry. As there is still limited research focused on the comprehensive extraction and determination of phenolics with different bound-forms, future efforts should take into account the non-targeted, pseudo-targeted, and spatial metabolomic profiling of phenolic compounds, and the construction of phenolic compound database for identifying and quantifying new types of phenolic compounds in oilseeds and their derived products.

Caffeoylquinic acids: chemistry, biosynthesis, occurrence, analytical challenges, and bioactivity

Caffeoylquinic acids (CQAs) are specialized plant metabolites we encounter in our daily life. Humans consume CQAs in mg-to-gram quantities through dietary consumption of plant products. CQAs are considered beneficial for human health, mainly due to their anti-inflammatory and antioxidant properties. Recently, new biosynthetic pathways via a peroxidase-type p-coumaric acid 3-hydroxylase enzyme were discovered. More recently, a new GDSL lipase-like enzyme able to transform monoCQAs into diCQA was identified in Ipomoea batatas. CQAs were recently linked to memory improvement; they seem to be strong indirect antioxidants via Nrf2 activation. However, there is a prevalent confusion in the designation and nomenclature of different CQA isomers. Such inconsistencies are critical and complicate bioactivity assessment since different isomers differ in bioactivity and potency. A detailed explanation regarding the origin of such confusion is provided, and a recommendation to unify nomenclature is suggested. Furthermore, for studies on CQA bioactivity, plant-based laboratory animal diets contain CQAs, which makes it difficult to include proper control groups for comparison. Therefore, a synthetic diet free of CQAs is advised to avoid interferences since some CQAs may produce bioactivity even at nanomolar levels. Biotransformation of CQAs by gut microbiota, the discovery of new enzymatic biosynthetic and metabolic pathways, dietary assessment, and assessment of biological properties with potential for drug development are areas of active, ongoing research. This review is focused on the chemistry, biosynthesis, occurrence, analytical challenges, and bioactivity recently reported for mono-, di-, tri-, and tetraCQAs.

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.

Sunflower Proteins at Air-Water and Oil-Water Interfaces

The adsorption of a sunflower protein extract at two air-water and oil-water interfaces is investigated using tensiometry, dilational viscoelasticity, and ellipsometry. For both interfaces, a three step mechanism was evidenced thanks to master curve representations of the data taken at different aging times and protein concentrations. At short times, a diffusion limited adsorption of proteins at interfaces is demonstrated. First, a two-dimensional protein film is formed with a partition of the polypeptide chains in the two phases that depends strongly on the nature of the hydrophobic phase: most of the film is in the aqueous phase at the air-water interface, while it is mostly in the organic phase at the oil-water interface. Then a three-dimensional saturated monolayer of proteins is formed. At short times, adsorption mechanisms are analogous to those found with typical globular proteins, while strong divergences are observed at longer adsorption times. Following the saturation step, a thick layer expands in the aqueous phase and appears associated with the release of large objects in the bulk. The kinetic evolution of this second layer is compatible with a diffusion limited adsorption of the minor population of polymeric complexes with hydrodynamic radius R_H ∼ 80 nm, evidenced in equilibrium with hexameric globulins (R_H ∼ 6 nm) in solution. These complexes could result from the presence of residual polyphenols in the extract and raise the question of the role of these compounds in the interfacial properties of plant protein extracts.

Bioaccessibility of cashew nut kernel flour compounds released after simulated in vitro human gastrointestinal digestion

Cashew nuts are mainly consumed as a roasted and salted snack. Lately, the industry has gained interest in broken kernels because of their added value. In this study, defatted cashew nut flour (DCF) underwent simulated gastrointestinal digestion to obtain a soluble (CDs) and an insoluble (CDi) digested fraction. These fractions, which resulted from the digestion of a complex matrix, were evaluated for antioxidant capacity of bioaccessible compounds (present on the soluble digested fraction, CDs) and their potential prebiotic effect, considering that the insoluble digested fraction (CDi) could be fermented by the microbiota in the gut. The DCF had a high protein content (40.74%), being nutritionally characterized as a balanced source of amino acids, with a predominance of aromatic amino acids (phenylalanine and tyrosine), threonine and histidine. The digested DCF presented 76.90% of the soluble components of low molecular weight (0.1-2 kDa), which is typical of antioxidant peptides. The soluble digested fraction (CDs) significantly increased the antioxidant capacity in relation to flour in the ORAC and ABTS assays and the aqueous extract presented the highest values (526.0 and 76.64 as µmol Trolox Eq./g sample, respectively). The CDs protected 29.03% of the supercoiled DNA band and ratified the potential antioxidant capacity after GID in a physiological assay. In addition, the insoluble digested fraction showed a potential prebiotic effect for Bifdobacterium lactis BB-12. Finally, simulated gastrointestinal digestion improves the bioaccessibility of CDF antioxidant compounds as a complex matrix, containing low molecular weight peptides and phenolic compounds, which become more available to react with reactive oxygen species (ROS). In addition, the potential prebiotic effect of defatted cashew nut flour has yielded a promising solution for the total reuse of broken cashew nut kernel as a functional food ingredient.

Potential of a Sunflower Seed By-Product as Animal Fat Replacer in Healthier Frankfurters

Upcycled defatted sunflower seed flour (SUN), a by-product obtained from sunflower oil extraction, was used as an animal fat replacer to develop healthier frankfurters. For that end, animal fat was replaced (~50%) with water and 2% or 4% of SUN. Nutritional composition, technological, structural and sensorial properties were evaluated. SUN incorporation led to a significant increase in protein, minerals (magnesium, potassium, copper and manganese) and a decrease in fat content (~37% less than control with all animal fat). The incorporation of SUN in frankfurters promoted the presence of phenolic compounds. Increasing SUN addition lead to an increasingly (p < 0.05) darker frankfurter colour. Samples with SUN at 4% were firmer than the control according to TPA and sensory analysis results and showed the highest lipid disorder attributed to more lipid interactions in the meat matrix. SUN addition as an animal fat replacer in frankfurters is a feasible strategy to valorise sunflower oil by-products and obtain healthier frankfurters.

Multi-objective optimization of solid/liquid extraction of total sunflower proteins from cold press meal

The impact of pH (6-9) and NaCl concentration (0-0.5 mol.L^-1) on sunflower protein extraction was studied through design of experiments. The considered criteria were protein extraction yield (total proteins, helianthinin and albumins), chlorogenic acids covalently bound to proteins, and free chlorogenic acid concentration in the aqueous extract. Statistical analysis showed that the obtained by design of experiments the polynomial models of each extraction criteria were reliable for predicting the responses. They were employed in an original multi-objective optimization methodology. The optimal conditions revealed to be pH 7.3/0.3 mol.L^-1 NaCl yielded 46.83% and 59.16% of total protein and albumin extraction yield, 1.730 and 1.998 mg.g^-1 of chlorogenic acids covalently bound to helianthinin and albumins in aqueous extract, respectively. The sunflower protein isolate obtained after extraction in this condition had good solubility (40-80% at pH 5-8), functional properties (foaming and emulsifying) and a satisfying color.