Untargeted metabolomics of fresh and heat treatment Tiger nut (Cyperus esculentus L.) milks reveals further insight into food quality and nutrition.

Tiger nut (Cyperus esculentus L.) is a crop traditionally grown in Valencia Region (Spain) and other temperate and tropical regions in the world, where its tubers are commonly consumed as tiger nut milk (horchata). Because of their nutritive potential and original taste, these products are beginning to spread internationally and, as consequence, analytical procedures to assess nutritional profiles, quality control issues are acquiring increasing relevance. The main objective of this study was to use an advance analytical method and chemometrics tools to determine if the ultra-high temperature (UHT) treatment necessary to extend the shelf life of tiger nut milk would affect the profile of nutrients when compared to fresh product. A cold solvent extraction followed by liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS) was used. Datasets obtained from UHT and fresh tiger nut milk data were analyzed through an untargeted metabolomics approach to compare chemical patterns, highlighting differences in citric acid esters of mono- diglycerides (CITREM) and monoacylglycerol (MAG) used as emulsifiers of UHT products, and a remarkably higher abundance of biotin, phosphatidic acid (PA) and L-arginine in fresh products. These results showed that untargeted metabolomics through high resolution tandem mass spectrometry allowed fine differences between food products to be found, therefore, the nutrient lost caused by UHT treatment was clearly discerned.

Rapid screening of low-molecular-weight phenols from persimmon (Diospyros kaki) pulp using liquid chromatography/UV-visible/electrospray mass spectrometry analysis.

BACKGROUND: Persimmon fruits have been widely used in traditional medicine owing to their phenolic composition. This research aims to perform a rapid, detailed and affordable study of the profile of low-molecular-weight phenols from persimmon pulp. RESULTS: Two different HPLC-DAD/ESI-MS(n) analyses were performed using a routine three-dimensional ion trap mass spectrometer to analyze the ethanolic extract of persimmon pulp: (1) an untargeted data-dependent analysis to identify the majority of small phenols that included full MS and MS(2) scan events; (2) a targeted data-dependent analysis to identify polymerized phenols (dimers and formic acid adducts) through a source-induced dissociation analysis that included full MS and MS(2) scan events. Thirty-two low-molecular-weight phenols were detected, comprising gallic acid and its glycoside and acyl derivatives, glycosides of p-coumaric, vanillic and cinnamic acids and different flavone di-C-hexosides, most of them reported for the first time in persimmon. CONCLUSION: The use of a straightforward and affordable methodology of analysis led to obtain an up-to-date profiling of low-molecular-weight phenols in persimmon. The results can help future actions aimed to expand the understanding of the phenolic metabolome of persimmon cultivars.

Volunteer stratification is more relevant than technological treatment in orange juice flavanone bioavailability.

The effect of two technological treatments on orange juice flavanone bioavailability in humans was assessed. Processing affected flavanone solubility and particle size of the cloud. Volunteers were stratified in high, medium, and low urinary excretion capabilities. Flavanones from high-pressure homogenized juice showed better absorption than those of conventional pasteurized juice in high excretors. These differences were not observed in medium and low excretors. High flavanone excretors took advantage of the high-pressure homogenization juice attributes (smaller cloud particle size) and showed an improved absorption/excretion. Stratification of the individuals by their excretion capability is more relevant than technological treatments in terms of flavanone bioavailability. This stratification should be considered in clinical studies with citrus juices and extracts as it could explain the large interindividual variability that is often observed.

Contribution of phospholipid pyrrolization to the color reversion produced during deodorization of poorly degummed vegetable oils.

The Ehrlich reaction was optimized to determine the formation of pyrrolized phospholipids in edible oils in an attempt to understand the color reversion produced during the deodorization of poorly degummed edible oils. The procedure consisted of the treatment of the oil with p-(dimethylamino)benzaldehyde in tetrahydrofuran/2-propanol at a controlled acidity and temperature and the spectrophotometric determination of adducts produced. The extinction coefficient of Ehrlich adducts was calculated by using 1-[1-(2-hydroxyethyl)-1H-pyrrol-2-yl]propan-1-ol (1) as a standard and was 15 300 M(-)(1) cm(-)(1). The response was linear and reproducible within the range of 0.334-48.6 microM of compound 1. When the assay was applied to a soybean oil treated with 100-1000 ppm of phosphatidylethanolamine and submitted to deodorization, the formation of pyrrolized phospholipids was observed at the same time that the disappearance of the phospholipid and the oil darkening were produced. The main changes were observed during the first steps of the deodorization process, when the oil was heated between 80 and 160 degrees C. During the initial heating of the oil until achieving 200 degrees C, oil darkening, phosphatidylethanolamine disappearance, and pyrrolized phospholipid formation were correlated, therefore suggesting a contribution of phospholipid pyrrolization to the oil darkening produced.

Oil stability prediction by high-resolution (13)C nuclear magnetic resonance spectroscopy.

(13)C NMR spectra of oil fractions obtained chromatographically from 66 vegetable oils were obtained and analyzed to evaluate the potential use of those fractions in predicting oil stabilities and to compare those results with oil stability prediction by using chemical determinations. The oils included the following: virgin olive oils from different cultivars and regions of Europe and north Africa; "lampante" olive, refined olive, refined olive pomace, low-erucic rapeseed, high-oleic sunflower, corn, grapeseed, soybean, and sunflower oils. Oils were analyzed for fatty acid and triacylglycerol composition, as well as for phenol and tocopherol contents. By using stepwise linear regression analysis (SLRA), the chemical determinations and the (13)C NMR data that better explained the oil stability determined by the Rancimat were selected. These selected variables were related to both the susceptibility of the oil to be oxidized and the content of minor components that most contributed to oil stability. Because (13)C NMR considered many more variables than those determined by chemical analysis, the predicted stabilities calculated by using NMR data were always better than those obtained by using chemical determinations. All these results suggest that (13)C NMR may be a powerful tool to predict oil stabilities when applied to chromatographically enriched oil fractions.