A high-performance liquid chromatography method validation and a Box-Behnken experimental design for the extraction optimization of quercitrin from Nectandra reticulata.

The ethanolic extract of Nectandra reticulata contains a high amount of quercetin-3-O-rhamnoside (quercitrin) that has exhibited a significant activity toward Alzheimer's disease, specifically with LXR receptors. In this work, a methodology was validated following the specifications of the International Conference of Harmonization in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy (recovery), repeatability (intra-assay), intermediate precision (intra-laboratory), reproducibility (inter-laboratory), robustness, and specificity. The effect of location (Oiba, Granada, and Chiquinquira) and the extraction method (percolation, maceration, and ultrasound-assisted extraction) towards the chromatographic profile and quercitrin recovery was studied. Furthermore, a Box-Behnken design was conducted to optimize quercitrin extraction and extraction yield by ultrasonic-assisted extraction. The chromatographic method was validated, with a linear range from 5 to 180 mg quercitrin per L, LOD 0.26 mg L-1, and LOQ 0.86 mg L-1. Accuracy [recovery of 93.8% (w/w)], repeatability (relative standard deviation, RSD, 3.3%), intermediate precision (RSD 5.4%), and reproducibility (RSD 1.4%) were within the acceptable values. The method was robust and specific, except for the variation in the formic acid concentration. The location had a greater influence than the extraction method towards both the chromatographic profile and quercitrin recovery. Quercitrin extraction was maximized at 60% (v/v) ethanol and 50 °C, independent of the solvent : material ratio used. The highest yield values were achieved at 60% (v/v) ethanol and 50 °C, with a solvent : material ratio of 40 mL g-1.

Utilization of red and yellow Coffea arabica var. Caturra pulp: macronutrient analysis, carotenoid extraction, and encapsulation for dairy product enrichment.

This study aimed to investigate the macronutrient and carotenoid content of red and yellow Coffea arabica var. Caturra pulp, a by-product of coffee processing in Colombia. The study employed ultra-sound-assisted extraction (UAE) to extract carotenoids, and a 23 factorial design was used to evaluate the effects of pulp color, biomass-solvent ratio, and solvent mixture composition on carotenoid content and extraction yield. The condition that provided the highest carotenoid extraction was further encapsulated by spray drying and added to a dairy product. The results showed that coffee pulp has significant dietary fiber content and high levels of carotenoids, with yellow pulp having a higher content than red pulp. Lutein isomers and lutein esters were the most abundant carotenoids found in both red and yellow coffee pulp. The highest carotenoid extraction was achieved using a 1:40 (g/mL) biomass:solvent ratio and a 20:80% v/v Ethanol:Ethyl Acetate solvent mixture for the yellow pulp. The carotenoid extract also demonstrated high encapsulation efficiency (46.57 ± 4.03%) and was found to be stable when added to a fermented milk product. This study presents an alternative solution for utilizing coffee by-products in Colombia, which could positively impact the families of over half a million Colombian coffee producers.

Cashew (Anacardium occidentale) Nut-Shell Liquid as Antioxidant in Bulk Soybean Oil.

Recently, natural antioxidants for the food industry have become an important focus. Cashew nut-shell liquid (CNSL) is composed of compounds that can act as natural antioxidants in food systems. The aim of this work was to evaluate the potential of CNSL and its components to act as natural antioxidants in a bulk oil system. CNSL was treated with calcium hydroxide to obtain two fractions [cardol/cardanols acid fraction (CCF) and anacardic acid fraction (AF)]. CNSL, FF and AF were analyzed by thin-layer chromatography and Fourier-transform infrared spectroscopy. The protective effects of CNSL, CCF and AF were tested in terms of the peroxide value of bulk soybean oil in accelerated assays and were compared against controls with and without synthetic antioxidants (CSA and CWA). CNLS, CCF, AF and CSA were tested at 200 mg/kg soybean oil by incubation at 30, 40, 50 and 60 °C for five days. The activation energy (Ea) for the production of peroxides was calculated by using the linearized Arrhenius equation. Thin-layer chromatography and Fourier-transform infrared spectroscopy revealed that (i) CNSL contained cardanols, anacardic acids, and cardols; (ii) CCF contained cardanols and cardols; and (iii) AF contained anacardic acids. CSA (Ea 35,355 J/mol) was the most effective antioxidant, followed by CCF (Ea 31,498 J/mol) and by CNSL (Ea 26,351 J/mol). AF exhibited pro-oxidant activity (Ea 8339 J/mol) compared with that of CWA (Ea 15,684 J/mol). Therefore, cardols and cardanols from CNSL can be used as a natural antioxidant in soybean oil.

Supercritical Fluid Extraction of Phenolic Compounds from Mango (Mangifera indica L.) Seed Kernels and Their Application as an Antioxidant in an Edible Oil.

Phenolic compounds from mango (M. indica) seed kernels (MSK) var. Sugar were obtained using supercritical CO2 and EtOH as an extraction solvent. For this purpose, a central composite design was carried out to evaluate the effect of extraction pressure (11-21 MPa), temperature (40-60 °C), and co-solvent contribution (5-15% w/w EtOH) on (i) extraction yield, (ii) oxidative stability (OS) of sunflower edible oil (SEO) with added extract using the Rancimat method, (iii) total phenolics content, (iv) total flavonoids content, and (v) DPPH radical assay. The most influential variable of the supercritical fluid extraction (SFE) process was the concentration of the co-solvent. The best OS of SEO was reached with the extract obtained at 21.0 MPa, 60 °C and 15% EtOH. Under these conditions, the extract increased the OS of SEO by up to 6.1 ± 0.2 h (OS of SEO without antioxidant, Control, was 3.5 h). The composition of the extract influenced the oxidative stability of the sunflower edible oil. By SFE it was possible to obtain extracts from mango seed kernels (MSK) var. Sugar that transfer OS to the SEO. These promissory extracts could be applied to foods and other products.

Vitamin C, protein, and dietary fibre contents as affected by genotype, agro-climatic conditions, and cooking method on tubers of Solanum tuberosum Group Phureja.

The simultaneous effect of genotype, agro-climatic conditions, and cooking method was evaluated towards the contents of vitamin C, protein, and soluble, insoluble, and total dietary fibre in potato tubers from the Group Phureja. Within the tested treatments, vitamin C was affected the most (9.4-85.1 mg/100 g DW), followed by insoluble dietary fibre (3.9-16.6 g/100 DW), soluble dietary fibre (1.0-3.9 g/100 g DW), total dietary fibre (3.6-fold change), and protein (1.7-4.3 g/100 g DW). The cooking method had a high effect on the variability of the contents of vitamin C, protein, insoluble dietary fibre, and total dietary fibre (74.2-92.8% of the total variance). In contrast, not only the cooking method, but also the agro-climatic conditions had a high effect on the content of soluble dietary fibre (32.6 and 34.8% of the total variance, respectively). Total dietary fibre had a protective effect on vitamin C upon cooking.

Influence of genotype, agro-climatic conditions, cooking method, and their interactions on individual carotenoids and hydroxycinnamic acids contents in tubers of diploid potatoes.

The effects of genotype, agro-climatic conditions (ACC), and cooking method as well as their interactions on the content of individual carotenoids and hydroxycinnamic acids in different potato tubers were evaluated. While zeaxanthin content was highly influenced by the ACC (up to 631-fold change), chlorogenic acid was similarly influenced by the cooking method (up to 3.1-fold increase after cooking), by the interactions ACC × cooking method (up to 2.1-fold increase) and genotype × cooking method (up to 1.7-fold increase). Stability/extractability of compounds after cooking was found to be genotype and ACC dependent, which suggest that genotype and ACC induces differential expression of genes for the biosynthesis pathways of carotenoids and hydroxycinnamic acids is different among, as well as components of the cellular matrix. These results are promising to apply in potato breeding programs with the perspective to develop new potato cultivars selected by their nutritional attributes.

Utilization of fruit pomace, overripe fruit, and bush pruning residues from Andes berry (Rubus glaucus Benth) as antioxidants in an oil in water emulsion.

Crude extracts were prepared from residues of Rubus glaucus Benth by using food-grade solvents. Their efficacy protecting lipid oxidation of an oil in water (O/W) emulsion as well as of a bulk oil was tested. Stability of lipids during storage of an O/W emulsion was tested by the hydroperoxides and thiobarbituric acid reactive species (TBARS) measurements. Bulk oil stability was measured by the Rancimat method. Fruit pomace crude extracts were the best controlling lipid oxidation of an O/W emulsion, with crude extracts from overripe fruit and bush pruning residues acting as pro-oxidants as measured by the hydroperoxides levels. Neither of the crude extracts was able to inhibit lipid oxidation of the bulk oil. Mathematical modelling revealed that despite total phenolic content and partition coefficient of the crude extracts are important parameters to control lipid oxidation of an O/W emulsion, they do not totally explain their behavior in food-like systems.

Hydroxycinnamic acids in cooked potato tubers from Solanum tuberosum group Phureja.

Hydroxycinnamic acids are phenolic compounds and are considered to have health promotion properties due to their antioxidant activity. Potato tubers of 113 genotypes of Solanum tuberosum group Phureja belonging to the Colombian Central Collection, landraces of potatoes, and commercial cultivars were evaluated for their hydroxycinnamic acids content. The composition of these compounds was analyzed using cooked tubers in two different agro-climatic conditions. The genotypes were analyzed for chlorogenic acid, neo-chlorogenic acid, crypto-chlorogenic acid, and caffeic acid by ultrahigh-performance liquid chromatography (UHPLC). Chlorogenic acid was the major representative and varied between 0.77 to 7.98 g kg-1 DW (dry weight) followed by crypto-chlorogenic acid (from 0.09 to 1.50 g kg-1 DW). Under moorland agro-climatic conditions even though the chlorogenic acid levels increased with respect to flatland agro-climatic conditions, the related isomer neo-chlorogenic acid decreased as compared to flatland conditions. The correlation between chlorogenic acid with the isomers, and with caffeic acid was positive. This study demonstrated that there is a wide variation in hydroxycinnamic acids contents in the germplasm studied, which can be exploited in breeding programs to contribute to human health.

Polyphenolic composition and antioxidant activity of açai (Euterpe oleracea Mart.) from Colombia.

Berries of Colombian Euterpe oleracea Mart. were analyzed for total phenolic content (TPC), anthocyanin (ACN) content, and antioxidant activity. Additionally, reversed-phase ultra-high performance liquid chromatography with photodiode array detection (RP-UHPLC-PDA) and heated electrospray ionization (HESI) multistage mass spectrometry (MS(n)) were used to determine the composition of phenolic compounds. Anthocyanin content was 0.57±0.39mg cyanidin-3-glucoside/g fresh weight (FW) and TPC was 6.07±2.17mg gallic acid equivalent (GAE)/g FW. The ABTS radical scavenging activity was 3.1±1.3µmol Trolox equivalents (TE)/100g FW, whereas the DPPH value was 2693.1±332.8µmol TE/100g FW. Overall, results show that Colombian açai has a more diverse polyphenolic profile and higher antioxidant activity than Brazilian açai. This information could be useful in authentification procedures to differentiate Brazilian açai from Colombian açai when used as an alternative for the supply of this fruit during the time of shortage in Brazil.

Natural variation of sucrose, glucose and fructose contents in Colombian genotypes of Solanum tuberosum Group Phureja at harvest.

BACKGROUND: Potato frying quality is a complex trait influenced by sugar content in tubers. Good frying quality requires low content of reducing sugars to avoid the formation of dark pigments. Solanum tuberosum Group Phureja is a valuable genetic resource for breeding and for genetic studies. The sugar content after harvest was analyzed in a germplasm collection of Group Phureja to contribute to the understanding of the natural variation of this trait. RESULTS: Sucrose, glucose and fructose genotypic mean values ranged from 6.39 to 29.48 g kg(-1) tuber dry weight (DW), from 0.46 to 28.04 g kg(-1) tuber DW and from 0.29 to 27.23 g kg(-1) tuber DW, respectively. Glucose/fructose and sucrose/reducing sugars ratios ranged from 1.01 to 6.67 mol mol(-1) and from 0.15 to 7.78 mol mol(-1) , respectively. Five clusters of genotypes were recognized, three of them with few genotypes and extreme phenotypic values. CONCLUSION: Sugar content showed a wide variation, representing the available variability useful for potato breeding. The results provide a quantitative approach to analyze the frying quality trait and are consistent with frying color. The analyzed germplasm presents extreme phenotypes, which will contribute to the understanding of the genetic basis of this trait. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of pectins on the mass transfer kinetics of monosaccharides, amino acids, and a corn oil-in-water emulsion in a Franz diffusion cell.

The effect of high (HMP) and low (LMP) methoxylated pectins (2%w/w) on the rate and extent of the mass transfer of monosaccharides, amino acids, and a corn oil-in-water emulsion across a cellulose membrane was evaluated. A sigmoidal response kinetic analysis was used to calculate both the diffusion coefficients (rate) and the amount of nutrients transferred through the membrane (extent). In all cases, except for lysine, HMP was more effective than LMP in inhibiting both the rate and extent of the mass transfer of nutrients through the membrane. LMP and HMP, e.g., reduced 1.3 and 3.0times, respectively, the mass transfer rate of glucose, as compared to control (containing no pectin), and 1.3 and 1.5times, respectively, the amount of glucose transferred through the membrane. Viscosity, molecular interactions, and flocculation were the most important parameters controlling the mass transfer of electrically neutral nutrients, electrically charged nutrients, and emulsified lipids, respectively.

Development and validation of a liquid chromatographic method to quantify sucrose, glucose, and fructose in tubers of Solanum tuberosum Group Phureja.

A High Performance Liquid Chromatography (HPLC) method was developed and validated to quantify sucrose (non-reducing sugar), glucose, and fructose (reducing sugars) in raw tubers of Solanum tuberosum Group Phureja. Chromatographic analysis was performed using an AMINEX HPX 87H column, at 18 °C, linked to a refraction index detector, at 35 °C. The eluent was 10mM sulfuric acid. The conditions established for the method provided an optimum separation of sugars, citric acid, and malic acid, with resolution values higher or equal to one. Among the four sugar extraction methods tested, the double 50% (v/v) aqueous methanol extraction gave the highest level of analytes. Recovery of this extraction method ranged between 94.14 and 99.77%. The HPLC method was validated for repeatability, reproducibility, linearity, and limits of detection, and quantification. Relative standard deviation was found to be lower than five, when testing repeatability and reproducibility, which is suitable considering a range of acceptability from 5.3 to 7.3. Additionally, the regression analyses supported the method linearity in a range of quantification from 3 to 100 mg/L with regression coefficients values greater than 0.998 for the three analytes. Limits of detection were 3.0 mg/L for the three sugars and limits of quantification were 2.0 mg/L for sucrose and 3.0 mg/L for glucose and fructose. Four Colombian commercial cultivars (Criolla Guaneña, Criolla Paisa, Criolla Galeras, and Criolla Colombia) and five landrace accessions from the Colombian Core Collection of Group Phureja were grown in the district of Usme (Bogotá) fields to analyze their sugar contents. Sucrose, glucose, and fructose contents were found ranging from 0.93 to 3.11 g/100 g tuber dried weight (DW), from 0.25 to 4.53 g/100 g tuber DW, and from 0.10 to 1.49 g/100 g tuber DW, respectively. Therefore, a high range in the variability of sugar contents was found among genotypes. However, the variability was low among technical replicates of the same genotype, revealing an accurate quantification of sugars in Group Phureja. This method can be used to assess the amount of reducing and non-reducing sugars accumulation in potato germplasm.

Interaction of a dietary fiber (pectin) with gastrointestinal components (bile salts, calcium, and lipase): a calorimetry, electrophoresis, and turbidity study.

An in vitro gastrointestinal model consisting of oral, gastric, and intestinal phases was used to elucidate the impact of pectin on the digestion of emulsified lipids. Pectin reduced the extent of lipid digestion, which was attributed to its binding interactions with specific gastrointestinal components. The interaction of pectin with bile salts, lipase, CaCl2, and NaCl was therefore investigated by turbidity, microstructure, electrophoresis, and isothermal titration calorimetry (ITC) at pH 7.0 and 37 °C. ITC showed that the interaction of pectin was endothermic with bile salts, but exothermic with CaCl2, NaCl, and lipase. Electrophoresis, microstructure, and turbidity measurements showed that anionic pectin formed electrostatic complexes with calcium ions, which may have decreased lipid digestion due to increased lipid flocculation or microgel formation because this would reduce the surface area of lipid exposed to the lipase. This research provides valuable insights into the physicochemical and molecular mechanisms of the interaction of pectin with gastrointestinal components that may affect the rate and extent of lipid digestion.

Impact of dietary fibers [methyl cellulose, chitosan, and pectin] on digestion of lipids under simulated gastrointestinal conditions.

A simulated in vitro digestion model was used to elucidate the impact of dietary fibers on the digestion rate of emulsified lipids. The influence of polysaccharide type (chitosan (cationic), methyl cellulose (non-ionic), and pectin (anionic)) and initial concentration (0.4 to 3.6% (w/w)) was examined. 2% (w/w) corn oil-in-water emulsions stabilized by 0.2% (w/w) Tween-80 were prepared, mixed with polysaccharide, and then subjected to an in vitro digestion model (37 °C): initial (pH 7.0); oral (pH 6.8; 10 min); gastric (pH 2.5; 120 min); and, intestinal (pH 7.0; 120 min) phases. The impact of polysaccharides on lipid digestion, ζ-potential, particle size, viscosity, and stability was determined. The rate and extent of lipid digestion decreased with increasing pectin, methyl cellulose, and chitosan concentrations. The free fatty acids released after 120 min of lipase digestion were 46, 63, and 81% (w/w) for methyl cellulose, pectin, and chitosan, respectively (3.6% (w/w) initial polysaccharide), indicating that methyl cellulose had the highest capacity to inhibit lipid digestion, followed by pectin, and then chitosan. The impact of the polysaccharides on lipid digestion was attributed to their ability to induce droplet flocculation, and/or due to their interactions with molecular species involved in lipid hydrolysis, such as bile salts, fatty acids, and calcium. These results have important implications for understanding the influence of dietary fibers on lipid digestion. The control of lipid digestibility within the gastrointestinal tract might be important for the development of reduced-calorie emulsion-based functional food products.

Diversity of (dihydro) hydroxycinnamic acid conjugates in Colombian potato tubers.

In potato tuber, caffeic acid (the predominant hydroxycinnamic acid (HCA)), its conjugates (HCAcs; i.e. chlorogenic acid (ChA), crypto-ChA, and neo-ChA), and anthocyanin-linked HCAs have been extensively described in the literature. In contrast, only little information is available on the occurrence of other HCAcs and didydrohydroxycinnamic acid conjugates (DHCAcs). Fifteen Colombian potato cultivars were screened for these less commonly described conjugates by reversed-phase ultrahigh performance liquid chromatography coupled to a diode array detector and a heated electrospray ionisation mass spectrometer. A total of 62 HCAs/HCAcs/DHCAcs were found in extracts from peel and flesh. Among them, only twelve compounds were common to all cultivars in both peel and flesh. The less commonly described compounds accounted for 7.1-20.1% w/w of the total amount of HCAs/HCAcs/DHCAcs in whole tubers, highlighting their contribution to the total phenolic profile of potato tubers. Among all cultivars, the abundance (mg/100 g DW whole tuber) of neo-ChA (0.8-7.4) ranged in similar quantities as the less commonly reported feruloyl octopamine (1.2-5.2), 5-O-feruloyl quinic acid (0.1-7.5), cis-ChA (1.1-2.2), caffeoyl putrescine (0.6-2.5), sinapoyl hexose (0.1-1.8), N(1),N(14)-bis-(dihydrocaffeoyl) spermine (0.2-1.7), N(1),N(10)-bis-(dihydrocaffeoyl) spermidine (1.1-2.6), and N(1),N(5),N(14)-tris-(dihydrocaffeoyl) spermine (trace - 11.1).

Quantitative fate of chlorogenic acid during enzymatic browning of potato juice.

The quantitative fate of chlorogenic acid (ChA) during enzymatic browning of potato juice was investigated. Potato juice was prepared in water without the use of any antibrowning agent (OX treatment). As a control, a potato juice was prepared in the presence of NaHSO(3) (S control). To study the composition of phenolic compounds in potato in their native states, also a potato extract was made with 50% (v/v) methanol containing 0.5% (v/v) acetic acid (MeOH control). Water-soluble low molecular weight fractions (LMWFs) and high molecular weight fractions (HMWFs) from S and OX extracts were obtained by ultrafiltration and dialysis, respectively. Pellets obtained after the OX treatment and the S and MeOH controls were also analyzed for ChA content. Whereas in the S-LMWF all ChA was converted to sulfonic acid adducts, no free ChA was found in the OX-LMWF, indicating its high reactivity upon enzymatic browning. Analysis of protein in the HMWFs showed a higher content of "reacted" ChA in OX (49.8 ± 7.1 mg ChA/100 g potato DW) than in S (14.4 ± 1.5 mg ChA/100 g potato DW), as evidenced by quinic acid release upon alkaline hydrolysis. The presence of quinic acid in S-HMWF was unexpected, but a mass balance incorporating the ChA content of LMWF, HMWF, and pellet for the three extractions suggested that ChA might have been attached to polymeric material, soluble in the aqueous environment of S but not in that of MeOH. Size exclusion chromatography, combined with proteolysis, revealed that ChA reacted with patatin and protease inhibitors to produce brown soluble complexes.

Ablandamiento d frutos de pitaya amarilla (acathocereus pitajaya) a temperatuura ambiente y en refrigeración: actividad de poligalacturonasa, celulasa y xilanasa / Yellow Pitaya (Acanthocereus pitajaya) Fruit Softening During its Storage at Room Temperature and on Refrigerated Conditions: Polygalacturonase, Celualase and Xilanase Activities

Una de las mayores causas de pérdidas poscosecha de frutos de pitaya amarilla es su ablandamiento excesivo, el cual ha sido documentado previamente cuando la fruta es almacenada a temperaturas de cosecha o después de refrigeración. Además, tratamientos de choque térmico antes del almacenamiento refrigerado ofrecen control en el ablandamiento de estos frutos. Diferentes experimentos fueron llevados a cabo para evaluar el papel de algunas enzimas degradadoras de pared celular en el ablandamiento de frutos de pitaya amarilla: almacenamiento a 18 °C (TA) y refrigeración con choque térmico previo (ChT-R). Se incluyó también un tratamiento refrigerado control, sin choque térmico (control-R). Si midió el color de la corteza, la firmeza y las actividades de poligalacturonasa (PG), celulasa (CEL) y xilanasa (XIL). La evaluación del color indicó que los frutos almacenados a TA alcanzaron su madurez comercial luego de seis días. Luego de 12 días de almacenamiento a TA el pardeamiento y ablandamiento excesivo afectaron negativamente la calidad de los frutos. El pardeamiento y ablandamiento excesivo fueron detectados también en los frutos control-R cuando se movieron de 2 a 18 °C. Un ligero pardeamieno fue observado en los frutos ChT-R. Estos frutos alcanzaron su madurez comercial luego de 24 días de almacenamiento (nueve días luego de terminado el almacenamiento refrigerado). La actividad de XIL se asoció al ablandamiento en los frutos almacenados a TA y ChT-R. No se observó una clara correlación entre las actividades de PG y el ablandamiento, como tampoco entre CEL y el ablandamiento.

One of the major causes of yellow pitaya fruit loss during its marketing is its excessive softening, which has been previously documented when the fruit is stored at harvest temperature or after refrigeration. Furthermore, its excessive softening has been controlled by the application of heat shock treatments before refrigeration. Different experiments were carried out to evaluate the role of cell wall degrading enzymes on yellow pitaya fruit softening: storage at 18 °C (RT) as well as refrigeration with previous heat shock treatment (HS-R). A refrigerated control, without heat shock, was included (control-R). Peel color, firmness, poligalacturonase (PG), celulase (CEL) and xilanase (XIL) activities were measured. RT fruits reached the commercial ripeness after six days, as indicated by the color evaluation. After 12 days of storage at RT browning and excessive softening negatively affected the fruit quality. Browning and excessive softening were also detected in the control-R fruit when moving from 2 to 18°C. Minor browning was found in the HS- R fruit. HS-R fruit was full ripe 24 days of storage (nine days after finishing the refrigerated storage). XIL activity was associated to the softening in the RT and HS-R fruits. No clear correlation was observed between PG and softening neither between CEL and softening.

Determination of carotenoids, total phenolic content, and antioxidant activity of Arazá (Eugenia stipitata McVaugh), an Amazonian fruit.

The fruit of Arazá (Eugenia stipitata McVaugh) native to the Colombian Amazon is considered a potentially economically valuable fruit for the Andean economy due to its novel and unique taste. The fruit has an intense yellow color, but its chemical composition and properties have not been well studied. Here we report the identification and quantitation of carotenoids in the ripe fruit using high performance liquid chromatography (HPLC) with photodiode array detector (PDA) and atmospheric pressure chemical ionization (APcI) mass spectrometry (MS/MS). The qualitative carotenoid profile of the fruit according to maturity stage was also observed. Furthermore, antioxidant activity of the peel and pulp were assessed using the ferric reducing ability of plasma (FRAP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, in addition to chemical indexes and total phenolic content. Multiple carotenoids were identified in the peel and pulp including four xanthophylls (free and esterified as their mono and diesters) and two carotenes. One of the xanthophylls was tentatively identified as zeinoxanthin, while the others were identified as lutein, zeaxanthin, and ß-cryptoxanthin. Carotenes included α-carotene and ß-carotene. The total carotenoid content was significantly higher in the peel (2484 ± 421 µg/100 g FW) than in the pulp (806 ± 348 µg/100 g FW) with lutein, ß-cryptoxanthin, and zeinoxanthin as the major carotenoid components. The unique carotenoid composition of this fruit can differentiate it from other carotenoid-rich fruits and perhaps be useful in authentication procedures. Overall, results from this study suggest that Colombian Arazá may be a good edible source of carotenoids important in retinal health as well as carotenoids with provitamin A activity. Therefore, Arazá fruit can be used as a nutraceutical ingredient and in production of functional foods in the Colombian diet.

Inhibition of enzymatic browning of chlorogenic acid by sulfur-containing compounds.

The antibrowning activity of sodium hydrogen sulfite (NaHSO(3)) was compared to that of other sulfur-containing compounds. Inhibition of enzymatic browning was investigated using a model browning system consisting of mushroom tyrosinase and chlorogenic acid (5-CQA). Development of brown color (spectral analysis), oxygen consumption, and reaction product formation (RP-UHPLC-PDA-MS) were monitored in time. It was found that the compounds showing antibrowning activity either prevented browning by forming colorless addition products with o-quinones of 5-CQA (NaHSO(3), cysteine, and glutathione) or inhibiting the enzymatic activity of tyrosinase (NaHSO(3) and dithiothreitol). NaHSO(3) was different from the other sulfur-containing compounds investigated, because it showed a dual inhibitory effect on browning. Initial browning was prevented by trapping the o-quinones formed in colorless addition products (sulfochlorogenic acid), while at the same time, tyrosinase activity was inhibited in a time-dependent way, as shown by pre-incubation experiments of tyrosinase with NaHSO(3). Furthermore, it was demonstrated that sulfochlorogenic and cysteinylchlorogenic acids were not inhibitors of mushroom tyrosinase.

New insights into an ancient antibrowning agent: formation of sulfophenolics in sodium hydrogen sulfite-treated potato extracts.

The effect of sodium hydrogen sulfite (S), used as antibrowning agent, on the phenolic profile of potato extracts was investigated. This extract was compared to one obtained in the presence of ascorbic acid (A). In the presence of A, two major compounds were obtained, 5-O-caffeoylquinic acid (5-CQA) and 4-O-caffeoyl quinic acid. With S, their 2'-sulfo-adducts were found instead, the structures of which were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry. Also, for minor caffeoyl derivatives and quercetin glycosides, the corresponding sulfo-adducts were observed. Feruloyl and sinapoyl derivatives were not chemically affected by the presence of S. Polyphenol oxidase (PPO) was thought to be responsible for the formation of the sulfo-adducts. This was confirmed by preparing 2'-sulfo-5-O-caffeoyl quinic acid in a model system using 5-CQA, sodium hydrogen sulfite, and PPO. This sulfo-adduct exhibited a small bathochromic shift (λmax 329 nm) as compared to 5-CQA (λmax 325 nm) and a strong hypochromic shift with an extinction coefficient of 9357±395 M(-1) cm(-1) as compared to 18494±196 M(-1) cm(-1), respectively. The results suggest that whenever S is used as an antibrowning agent, the O-quinone formed with PPO reacts with S to produce sulfo-O-diphenol, which does not participate in browning reactions.