Impact of culinary heat treatment on Lodosa Piquillo peppers (Capsicum annuum L.): Total phenolic content and antioxidant capacity

Introduction: An emerging concept of disease prevention is ground-breaking these days. Research has been done to examine the possibility that the most common diseases affecting people worldwide may be preventable by a healthy diet. Antioxidants have been the focus of major attention in the attempt for reducing morbidity and mortality from chronic diseases because of their capacity to delay or inhibit oxidative damage (the attack of oxygen-containing free radicals on biological molecules) to a target molecule, linked to various diseases. In the present study, jarred Lodosa Piquillo peppers (Capsicum annuum L.) have been brought into sharp focus, as they are one of the most traditional crops in the region of Navarre. Peppers are rich in antioxidants, but these ones are subjected to a jarring process before they are consumed. For that reason, the principal aim of this study was to examine the influence of different cooking techniques on the antioxidant properties of Lodosa Piquillo peppers. Material and methods: Extracts from jarred Lodosa Piquillo peppers (PDO) were examined. These vegetables were subjected to different cooking methods, microwave heating (1-minute heating at 750 W) and frying (6-minute heating at 90 oC in a pan previously heated at 110 oC for 5 minutes) and were compared to the raw sample. Total phenolic content was quantified following Folin-Ciocalteu methodology using a Spectrophotometer, and the antioxidant capacity was evaluated by DPPH and ABTS assays. Results: Total phenolic content and the antioxidant capacity of jarred Piquillo peppers was not significantly affected by additional thermal treatments in microwaved and fried samples, compared to raw jarred peppers. Conclusion: Additional cooking techniques do not significantly affect the antioxidant capacity of Lodosa Piquillo peppers once they are exposed to a jarring process. Therefore, the antioxidant capacity of the Piquillo peppers is similar independent of how they are consumed.Introducción: La prevención de enfermedades es un concepto pionero que ha revolucionado el estudio de la nutrición estos últimos años. Se ha estudiado mucho la posibilidad de que una dieta saludable pueda prevenir enfermedades que afectan a la sociedad hoy en día. Así, los antioxidantes están siendo el principal foco dietético de estudio con el objetivo de reducir la morbilidad y mortalidad debida a estas enfermedades crónicas. Estos elementos de la dieta son capaces de inhibir o retrasar el daño oxidativo que se produce en las células, relacionado a varias enfermedades. En este estudio se ha examinado el pimiento del Piquillo de Lodosa (Capsicum annuum L.), una de las cosechas más tradicionales en la región de Navarra. Los pimientos son reconocidos por su alto contenido en antioxidantes, pero en este caso, los pimientos se someten a un proceso de embotado. Por ello, el principal objetivo de este estudio fue analizar el efecto del tratamiento térmico en las propiedades antioxidantes del pimiento del Piquillo. Material y métodos: Se analizaron extractos del pimiento del Piquillo de Lodosa (DOP). Estos pimientos fueron sometidos a dos diferentes métodos culinarios, calentamiento al microondas (1 minuto a 750 W) y fritura (6 minutos de cocción a 90 oC en una sartén previamente calentada a 110 oC por 5 minutos), y fueron comparados con la muestra en crudo. Se cuantificó el contenido fenólico total de las muestras mediante la técnica Folin-Ciocalteu usando un espectrofotómetro, así como la capacidad antioxidante de los vegetales siguiendo la metodología de DPPH y ABTS. Resultados: Tanto el contenido fenólico total como la capacidad antioxidante de los pimientos del Piquillo no sufrieron cambios significativos tras la cocción en microondas o mediante fritura, en comparación con los pimientos en conserva. Conclusión: Las propiedades antioxidantes de los pimientos del Piquillo de Lodosa son similares independientemente del modo de consumo

Impact of blanching and frying heating rate/time on the antioxidant capacity and (poly)phenols of cardoon stalks (cynara cardunculus L. var. altilis DC)

This study assessed the influence of blanching and frying heating rate/time on the antioxidant capacity and (poly)phenols of cardoon stalks (Cynara cardunculus L. var. altilis DC). Blanching (98 °C, 30 s) increased the total native chlorogenic acids content (1.2-fold vs raw cardoon), with no significant changes in DPPH antioxidant capacity, but with a decrease in ABTS antioxidant capacity (0.6-fold). Specifically, total di-caffeoylquinic acids (CQAs) increase (1.6-fold) counterbalanced the losses of 5-CQA (0.8-fold). All frying conditions (t85°C = 5, 12 or 10 min, ttotal = 15, 15 or 30 min, respectively) decreased the antioxidant capacity (0.5–0.7-fold in DPPH, 0.5–0.9-fold in ABTS) of cardoon, but increased total flavonoid amount (3.6–3.7-fold) that remained at low levels. The Short (15 min) and Intense-heat Frying (t85°C = 5 min) favoured the release of chlorogenic acids, particularly 5-CQA, from the food matrix. However, a longer frying process (30 min) induced an almost complete degradation of di-CQAs. Thus, it is desirable to limit the frying duration. When blanching and frying were combined, a higher thermal degradation of (poly)phenols was observed, but the Short and Intense-heat Frying remained the most suitable. This study highlights the importance of selecting optimal culinary conditions for vegetables that favour a high content on bioactive compounds and, therefore, their potential healthy properties

Application of multivariate analysis to investigate potential antioxidants in conventional and torrefacto roasted coffee

In the present work multivariate statistical techniques were applied to the coffee compounds and the overall antioxidant capacity of commercial conventional and torrefacto roasted coffees in order to investigate the main antioxidant compounds in coffee. Statistical analyses showed significant correlations between browned compounds, trigonelline, 5-caffeoylquinic acid and cafeic acid contents with the antioxidant activity measured by both DPPH- and redox potential methods. Trigonelline solutions showed an antioxidant capacity close to zero and should not be considered as a potential antioxidant compound. Principal Component Analysis (PCA) was applied to evidence the correlations between antioxidant capacity and coffee chemical compounds. Conventional and torrefacto roasted coffees were separated by PC1 (62.5% of the total variance) characterized by antioxidant capacity and chemical compounds highly correlated with antioxidant capacity. Furthermore, a descriptive chemical characterization of conventional and torrefacto ground roasted coffee has been carried out. Sixty-nine volatile compounds were identified and quantified. Their negative correlations with antioxidant capacity suggest a prooxidant capacity that should need further investigations

Influence of coffee/water ratio on the final quality of espresso coffee

Espresso coffee is a polyphasic beverage in which the physico-chemical and sensory characteristics obviously depend on both the selection of ground roasted coffee and the technical conditions of the percolation process. The aim of this work was to evaluate the influence of the coffee/water ratio on the physico-chemical and sensory quality of espresso coffee. Furthermore, the influence of botanical varieties (Arabica and Robusta) and the type of roast (conventional and torrefacto) on the selection of coffee/water ratio was studied. The relationship between pH and the perception of acidity intensity is discussed in relation to the influence of the coffee/water ratio, type of coffee and roast. The optimisation of other technical parameters in previous studies seemed to minimise the influence of an increase in the coffee/water ratio on the extraction of soluble and solid compounds. In fact, only some sensory attributes, such as bitterness, astringency and burnt, acrid and earthy/musty flavours were proposed as relevant to the selection of 6.5 g 40 mL(-1) or 7.5 g 40 mL(-1) in conventional roasted coffees (Arabica 100% and Robusta blend), and 6.5 g 40 mL(-1) in torrefacto roasted coffees. On the other hand, the addition of sugar during the roasting process in torrefacto roast coffees seemed to contribute to a higher generation of acids, melanoidins and other compounds by the Maillard reaction or caramelisation, which led us to select the lowest coffee/water ratio

Assessment of total (free and bound) phenolic compounds in spent coffee extracts

Spent coffee is the main byproduct of the brewing process and a potential source of bioactive compounds, mainly phenolic acids easily extracted with water. Free and bound caffeoylquinic (3-CQA, 4-CQA, 5-CQA), dicaffeoylquinic (3,4-diCQA, 3,5-diCQA, 4,5-diCQA), caffeic, ferulic, p-coumaric, sinapic, and 4-hydroxybenzoic acids were measured by HPLC, after the application of three treatments (alkaline, acid, saline) to spent coffee extracts. Around 2-fold higher content of total phenolics has been estimated in comparison to free compounds. Phenolic compounds with one or more caffeic acid molecules were approximately 54% linked to macromolecules such as melanoidins, mainly by noncovalent interactions (up to 81% of bound phenolic compounds). The rest of the quantitated phenolic acids were mainly attached to other structures by covalent bonds (62-97% of total bound compounds). Alkaline hydrolysis and saline treatment were suitable to estimate total bound and ionically bound phenolic acids, respectively, whereas acid hydrolysis is an inadequate method to quantitate coffee phenolic acids

Antioxidant and genoprotective effects of spent coffee extracts in human cells

Spent coffee has been shown as a good source of hydrophilic antioxidant compounds. The ability of two spent coffee extracts rich in caffeoylquinic acids, mainly dicaffeoylquinic acids, and caffeine (Arabica filter and Robusta espresso) to protect against oxidation and DNA damage in human cells (HeLa) was evaluated at short (2 h) and long (24 h) exposure times. Cell viability (MTT) was not affected by spent coffee extracts (>80%) up to 1000 mu g/mL after 2 h. Both spent coffee extracts significantly reduced the increase of ROS level and DNA strand breaks (29-73% protection by comet assay) induced by H2O2. Pretreatment of cells with robusta spent coffee extract also decreased Ro photosensitizer-induced oxidative DNA damage after 24 h exposure. The higher effectiveness of Robusta spent coffee extract, with less caffeoylquinic acids and melanoidins, might be due to other antioxidant compounds, such as caffeine and other Maillard reaction products. This work evidences the potential antioxidant and genoprotective properties of spent coffee in human cells

Digestibility of (Poly)phenols and Antioxidant Activity in Raw and Cooked Cactus Cladodes (Opuntia ficus-indica)

This study aims to investigate whether heat treatment applied to cactus cladodes influences the bioaccessibility of their (poly)phenolic compounds after simulated gastric and intestinal digestion. A total of 45 (poly)phenols were identified and quantified in raw and cooked cactus cladodes by ultra high performance liquid chromatography photodiode array detector high resolution mass spectrometry. Both flavonoids (60-68% total), mainly isorhamnetin derivatives, and phenolic acids (32-40%) with eucomic acids as the predominant ones significantly ( p < 0.05) increased with microwaving and griddling processes. After in vitro gastrointestinal digestion, 55-64% of the total (poly)phenols of cooked cactus cladodes remained bioaccessible versus 44% in raw samples. Furthermore, digestive conditions and enzymes degraded or retained more flavonoids (37-63% bioaccessibility) than phenolic acids (56-87% bioaccessibility). Microwaved cactus cladodes contributed the highest amount of (poy)phenols (143.54 mg/g dm) after gastrointestinal process, followed by griddled samples (133.98 mg/g dm), showing the highest antioxidant capacity. Additionally, gastrointestinal digestion induced isomerizations among the three stereoisomeric forms of piscidic and eucomic acids

Changes in volatile compounds and overall aroma profile during storage of coffee brews at 4 and 25 degrees C

In this work, the chemical changes occurring in the volatile fraction of Arabica coffee brews during storage at 4 and 25 degrees C for 30 days have been characterized for the first time by means of HS-GC-MS. A total of 47 compounds were identified and quantified: 2 sulfur compounds, 7 aldehydes, 3 esters, 15 furans, 5 ketones, 1 alcohol, 2 thiophenes, 4 pyrroles, 1 pyridine, 5 pyrazines, 1 alkene, and 1 acid. No new volatile compounds were detected at the end of the storage time. The changes observed are, in general, slower and less pronounced at refrigeration temperature. Storage also affects the sensory characteristics of the stored coffee brews, which lose part of their aroma intensity and freshness, acquiring some nondesirable notes such as rancid aroma, mainly during storage at 25 degrees C. Furthermore, seven aroma indices have been proposed as indicators of coffee brew staling, which show a good correlation with some sensory attributes, not only for aroma but also overall sensory quality. Consequently, they could be considered useful to monitor both the "age" and the sensory quality of stored coffee brews

Application of multivariate analysis to the effects of additives on chemical and sensory quality of stored coffee brew

The aim of this work was to obtain a black coffee brew to be consumed hot by extension of its shelf life, by addition of additives. Four pH-regulator agents (sodium and potassium carbonates and bicarbonates), one pH regulator and antioxidant (sodium citrate), three antioxidants [sodium ascorbate, ethylenediaminetetracetic acid (EDTA), and sodium sulfite], and lactoserum were tested by sensory analysis. Sodium carbonate and bicarbonate were selected for a study of the physicochemical (soluble and volatile compounds related to the sensory properties) and sensorial quality of coffee brew stored for 90 days at 4 degrees C. Although both additives extended the shelf life of the coffee brew up to 60 days, sodium carbonate was the chosen additive because it was the most useful in limiting the pH decrease and perception of sourness, which are some of the main factors involved in the rejection of stored coffee brews, and it better maintained the aroma and taste/flavor. Moreover, the application of multivariate analysis facilitated first the description of the global changes of the coffee brews with or without additives throughout the storage using principal component analysis and second the obtainment of a simple equation only with pH and caffeic acid parameters to discriminate the three types of coffee brews and simplify the analytical process, by means of the stepwise discriminant analysis

Raw and sous-vide-cooked red cardoon stalks (Cynara cardunculus L. var. altilis DC): (poly)phenol bioaccessibility, anti-inflammatory activity in the gastrointestinal tract, and prebiotic activity

The in vitro anti-inflammatory and prebiotic activity and the content and profile of bioaccessible (poly)phenols and catabolites of raw and sous-vide-cooked red cardoon (Cynara cardunculus L. var. altilis DC) were investigated during gastrointestinal (GI) digestion. Raw cardoon after in vitro GI digestion had 0.7% bioaccessible (poly)phenols, which protected against lipopolysaccharide-induced inflammation by counteracting IL-8, IL-6, TNF-α, and IL-10 secretions in differentiated Caco-2 cells. Contrarily, GI-digested sous vide cardoon showed higher (poly)phenol bioaccessibility (59.8%) and exerted proinflammatory effects in Caco-2 cells. (Poly)phenols were highly metabolized during the first 8 h of in vitro fermentation, and nine catabolites were produced during 48 h of fermentation. Colonic-fermented raw and sous-vide-cooked cardoon did not show anti-inflammatory activity in HT-29 cells but presented potential prebiotic activity, comparable to the commercial prebiotic FOS, by stimulating health-promoting bacteria such as Bifidobacterium spp. and Lactobacillus/Enterococcus spp. and by increasing the production of total SCFAs, especially acetate