Unlocking peach juice byproduct potential in food waste biorefineries: Phenolic compounds profile, antioxidant capacity and fermentable sugars

This work assesses an integrated pathway for the revalorization of peach byproduct (PB) within a biorefinery. PB was subjected to an oven-drying (OD) treatment for its evaluation as a storage treatment. It was compared to freeze-drying and untreated material in terms of antioxidant capacity (AOC), phenolic compounds (PC) profile and fermentable sugar production. OD reduced the water content to less than 15 % while preserving the bound hydrolysable polyphenols, which were the more abundant PC (≈64 %) with the highest AOC. Drying treatments hampered polysaccharide accessibility, but some enzyme preparations released 60-70 g/L of fermentable sugars at relatively high solids loading (10 %). This study proposes a novel enzyme-based strategy for the valorisation of fermentable sugars and antioxidant compounds from PB. The sugars can be fermented into several building blocks while the solid residue enriched in recalcitrant phenolic compounds and proteins could be used to develop novel functional products for food/feed sectors.

Untargeted metabolomic study by liquid chromatography-mass spectrometry in brain tissues on the effects of combined cocaine and ethanol self-administration in male and female young rats

The combined use of ethanol and cocaine is frequent among drug-abuse users and leads to further exacerbation of health consequences compared to individual consumption and this is of special concern during the transition to adulthood. Despite its high prevalence, the effect of combined consumption of cocaine and ethanol has been scarcely studied. In this work, we report the first untargeted metabolomic study in brain tissues to contribute to the advancement in the knowledge of the possible neurobiological effects of this polysubstance dependence. Liquid Chromatography coupled to high resolution Mass Spectrometry was employed to analyze three different brain tissues samples, prefrontal cortex, striatum and hippocampus, from male and female young rats exposed intravenously to a self-administration of these drugs. After optimizing the best sample treatment and selecting the chromatographic and detection conditions to find the maximum number of significant features (possible biomarker metabolites), the high resolution of the Orbitrap analyzer used in this work has made it possible to find up to 761 significant features with assigned molecular formula, of which up to 190 were tentatively identified and 44 unequivocally confirmed. The results demonstrated that the altered metabolic pathways are involved in multiple functions: receptor systems, such as the Glutamine-Glutamic acid-GABA axis or the catecholamine pathway, purinergic and pyrimidine pathways, fatty acids or oxidative stress, among others.

Perfusion reversed-phase high-performance liquid chromatography/mass spectrometry analysis of intact soybean proteins for the characterization of soybean cultivars

Perfusion reversed-phase HPLC (RP-HPLC)-electrospray mass spectrometry (ESI-MS) was employed for the characterization of soybean cultivars through the analysis of intact soybean proteins. The similarities and differences between yellow soybeans (the most usual soybeans) and other beans with different pigmentation (green, red, and black) commercialized as soybean were investigated. Red beans commercialized as azuki that are frequently sold as red soybean were also analyzed. Separation was carried out using a perfusion column at a flow-rate of 0.5 mL/min and a gradient elution. A step-by-step procedure was used for the optimization of the mass spectrometry parameters enabling the most sensitive detection. The method was applied to the analysis of the above-mentioned beans and the main soybean proteins (11S and 7S globulins) obtained by a fractionation procedure. MS spectra obtained from every peak in the beans and in their fractions were compared observing clear differences between yellow soybeans and the other beans with different pigmentation. The identification of some soybean proteins in yellow soybeans was also possible.

Identification of Marker Proteins for the Adulteration of Meat Products with Soybean Proteins by Multidimensional Liquid Chromatography−Tandem Mass Spectrometry

Soybean proteins are frequently added to processed meat products for economic reasons and to improve their functional properties. Monitoring of the addition of soybean protein to meat products is of high interest due to the existence of regulations forbidding or limiting the amount of soybean proteins that can be added during the processing of meat products. We have used chromatographic prefractionation on the protein level by perfusion liquid chromatography to isolate peaks of interest from extracts of soybean protein isolate (SPI) and of meat products containing SPI. After enzymatic digestion using trypsin, the collected fractions were analyzed by nanoflow liquid chromatography-tandem mass spectrometry. Several variants and subunits of the major seed proteins, glycinin and beta-conglycinin, were identified in SPI, along with two other proteins. In soybean-protein-containing meat samples, different glycinin A subunits could be identified from the peak discriminating between samples with and without soybean proteins added. Among those, glycinin G4 subunit A4 was consistently found in all samples. Consequently, this protein (subunit) can be used as a target for new analytical techniques in the course of identifying the addition of soybean protein to meat products.

Development of a perfusion reversed-phase HPLC method for the separation of soybean and cereal (wheat, corn, and rice) proteins in binary mixtures. Application to the detection of soybean proteins in commercial bakery products

A perfusion reversed-phase HPLC method enabling the simultaneous separation of soybean and cereal (wheat, corn, and rice) proteins in commercial bakery products has been proposed for the first time. The method utilises an acetonitrile-water gradient containing an ion-pairing agent. Different ion-pairing agents were tried, 0.3% (v/v) acetic acid being observed to enable the separation of soybean from wheat, rice, and corn proteins while with 0.1% (v/v) trifluoroacetic acid only the separation of soybean and corn proteins was possible. Optimisation of the solubilisation conditions for proteins was achieved by testing different acetonitrile concentrations for the simultaneous extraction of soybean and cereal proteins: best recoveries were found with 25% (v/v) acetonitrile + 0.3% (v/v) acetic acid and with 40% (v/v) acetonitrile + 0.1% (v/v) trifluoroacetic acid. Chromatographic conditions such as gradient, temperature, and wavelength detection were also optimised. The method enabled the separation of soybean and cereal proteins in binary mixtures (soybean and wheat, soybean and corn, or soybean and rice proteins) in less than 5 minutes in a total analysis time of 20 min.

Detection and quantitation of additions of soybean proteins in cured-meat products by perfusion reversed-phase high-performance liquid chromatography

Perfusion liquid chromatography has been applied in this work to the determination of soybean proteins in commercially available cured meat products, enabling the detection of additions of soybean proteins in cured meat products to which the addition of these vegetable proteins is forbidden and the quantitation of soybean proteins in cured meat products to which the addition of these proteins is allowed up to a certain limit. The analytical methodology is based on a sample treatment (fat extraction and soybean protein solubilization) prior to chromatographic analysis. Fat extraction with acetone and soybean protein solubilization with a buffer solution at basic pH (pH 10 or 9) were necessary to obtain selective and sensitive conditions. Use of water-acetonitrile-trifluoroacetic acid or water-tetrahydrofuran-trifluoroacetic acid linear binary gradients at a flow rate of 3 mL/min, a temperature of 50 degrees C, and UV detection at 280 nm enabled chromatographic analysis of soybean proteins in cured meat products in less than 3 min.

Simple and inexpensive method for the reliable determination of additions of soybean proteins in heat-processed meat products: an alternative to the AOAC official method

Despite the existence of an AOAC official method based on an enzyme-linked immunosorbent assay (ELISA) for the determination of additions of soybean proteins in meat products, its use for quantitative assessment is limited. Accordingly, a simple and inexpensive method has been developed and validated in this work. The method involves defatting the meat samples with acetone, solubilization of soybean proteins in a 30 mM Tris-HCl buffer (pH 8) containing 0.5% (v/v) 2-mercaptoethanol, and the identification of two peaks from soybean proteins in the chromatogram obtained by perfusion reversed-phase chromatography and UV detection. Determination of soybean proteins by the proposed method did not suffer from matrix interferences, with a good linear correlation up to a concentration of 12.50 mg/mL soybean proteins being observed. The proposed method was proven to be specific, precise, accurate, robust, and sensitive, making possible the detection and the quantitation of additions of 0.07% (w/w) and 0.25% (w/w), respectively, of soybean proteins in meat products (related to 1 g of initial product). The method has been applied to the determination of the soybean protein content in commercial heat-processed meat products, obtaining results that were statistically similar to those obtained by the official ELISA method but with a higher reliability and simplicity and a lower cost and analysis time.