Enhancing the polyphenol content of a red-fleshed Japanese plum (Prunus salicina Lindl.) nectar by incorporating a polyphenol-rich extract from the skins

BACKGROUND: Plum skins are a waste product generated during production of plum juice or pulp. Polyphenols, shown to have various health‐promoting properties, can be recovered from this waste product. Red‐fleshed plum nectar formulations containing plum skin extract in varying amounts were characterised in terms of intensity of sensory attributes, consumer acceptability, colour, polyphenol content and antioxidant activity. Commercial beverages containing red fruits were used as benchmarks. RESULTS: The polyphenolic profile of the plum skin extract was similar to that of the pulp, including anthocyanins, flavonols, flavan‐3‐ols and a phenolic acid. Addition of the extract to plum nectar, which enhanced the colour, polyphenol content and antioxidant capacity, was limited by its negative sensory impact. The formulations were deemed acceptable by consumers, although a decrease in positive sensory attributes (plum flavour, plum aroma and sweetness) and an increase in negative sensory attributes (plant‐like flavour, plant‐like aroma, acidity and astringency) were observed with increasing skin extract content. The formulations compared favourably with commercial beverages in terms of colour total polyphenol content and antioxidant activity. CONCLUSION: Plum skins were successfully used to enhance the functional status of plum nectar. Use of a functional ingredient from plum skins is, therefore, a feasible value‐addition strategy. Copyright © 2012 Society of Chemical Industry     

Enhancing aspalathin stability in rooibos (Aspalathus linearis) ready-to-drink iced teas during storage: the role of nano-emulsification and beverage ingredients, citric and ascorbic acids

BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready‐to‐drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin‐enriched green rooibos extract (GR) and aspalathin‐enriched green rooibos extract ascorbic acid solubilisate (GR‐solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of iced tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR iced tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso‐orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR iced tea formulations. Improved stability of aspalathin was noted in iced tea containing GR‐solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos iced teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry     

Modelling spatial externalities in panel data: The Spatial Durbin model revisited*

The purpose of this paper is twofold. First, it extends the spatial Durbin model to panel data allowing for non‐spherical disturbances and proposes two alternative estimators based on ML techniques. While one of the estimators exhibits more degrees of freedom, the other is computationally less burdensome. Results from a Monte Carlo study reveal that both estimators have satisfactory small sample properties also in cases when the error structure is in effect spherical. Second, the paper demonstrates that conventional testing procedures may wrongly reject the existence of spatial externalities. In particular, it shows that the incidence of a type II error increases as the spatial weight matrix becomes denser. Este artículo tiene un doble objetivo. Primero, amplia el modelo espacial de Durbin a datos de panel, permitiendo perturbaciones no esféricas y propone dos estimadores alternativos basados en técnicas de aprendizaje automático (ML). Mientras que uno de los estimadores exhibe un mayor número de grados de libertad, el otro es menos problemático en cuanto a su cómputo. Los resultados de un estudio de Monte Carlo mostraron que ambos estimadores poseen propiedades satisfactorias en cuanto a pequeños muestreos, incluso en casos en los que la estructura del error es de hecho esférica. Segundo, el artículo demuestra que los procedimientos convencionales de ensayo podrían rechazar erróneamente la existencia de externalidades espaciales. En particular, se muestra que la incidencia en un error de tipo II aumenta a medida que la matriz ponderada espacial se vuelve más densa.      

Indirect competitive enzyme-linked immunosorbent assay for the detection of native and heat-denatured bovine β-lactoglobulin in ewes' and goats' milk cheese

An indirect competitive enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of native and heat-denatured bovineβ-lactoglobulin (hd-β-lg) in goats' and ewes' milk cheese. Polyclonal antibodies raised in chicken against hd-β-lg were purified by immunadsorption chromatography on native bovine, ovine and caprineβ-lactoglobulins conjugated to CNBr-activated Sepharose. Although lactoglobulins from ewe, goat and cow have very similar amino acid sequences, crossreactivity was eliminated completely by this procedure. A commercially available goat-anti-chicken alkaline phosphatase conjugate was used as a secondary antibody to detect the anti-hd-β-lg antibodies bound to immobilized hd-β-lg. The detection limit of the assay was 100 ng/ml bovine native lg or hd-β-lg or 0.1–0.2% of cows' milk equivalent in cheese. Within a method validation study of the European Union, the ELISA test was successfully applied for the detection of native and heat-denatured bovine whey proteins in ewes' and goats' milk cheeses.     

NLRP1 in Cutaneous SCCs: An Example of the Complex Roles of Inflammasomes in Cancer Development

Protein complexes termed inflammasomes ensure tissue protection from pathogenic and sterile stressors by induction of inflammation. This is mediated by different caspase-1-induced downstream pathways, including activation of the pro-inflammatory cytokines proIL-1β and -18, induction of a lytic type of cell death, and regulation of the release of other pro-inflammatory molecules. Aberrant inflammasome activation underlies the pathology of numerous (auto)inflammatory diseases. Furthermore, inflammasomes support or suppress tumor development in a complex cell-type- and stage-dependent manner. In human keratinocytes and skin, NLRP1 is the central inflammasome sensor activated by cellular perturbation induced, for example, by UVB radiation. UVB represents the main inducer of skin cancer, which is the most common type of malignancy in humans. Recent evidence demonstrates that activation of NLRP1 in human skin supports the development of cutaneous squamous cell carcinomas (cSCCs) by inducing skin inflammation. In contrast, the NLRP1 inflammasome pathway is restrained in established cSCCs, suggesting that, at this stage, the protein complex has a tumor suppressor role. A better understanding of the complex functions of NLRP1 in the development of cSCCs and in general of inflammasomes in cancer might pave the way for novel strategies for cancer prevention and therapy. These strategies might include stage-specific modulation of inflammasome activation or its downstream pathways by mono- or combination therapy.     

Oxidative Stress Response’s Kinetics after 60 Minutes at Different (30% or 100%) Normobaric Hyperoxia Exposures

Oxygen is a powerful trigger for cellular reactions and is used in many pathologies, including oxidative stress. However, the effects of oxygen over time and at different partial pressures remain poorly understood. In this study, the metabolic responses of normobaric oxygen intake for 1 h to mild (30%) and high (100%) inspired fractions were investigated. Fourteen healthy non-smoking subjects (7 males and 7 females; age: 29.9 ± 11.1 years, height: 168.2 ± 9.37 cm; weight: 64.4 ± 12.3 kg; BMI: 22.7 ± 4.1) were randomly assigned in the two groups. Blood samples were taken before the intake at 30 min, 2 h, 8 h, 24 h, and 48 h after the single oxygen exposure. The level of oxidation was evaluated by the rate of reactive oxygen species (ROS) and the levels of isoprostane. Antioxidant reactions were observed by total antioxidant capacity (TAC), superoxide dismutase (SOD), and catalase (CAT). The inflammatory response was measured using interleukin-6 (IL-6), neopterin, creatinine, and urates. Oxidation markers increased from 30 min on to reach a peak at 8 h. From 8 h post intake, the markers of inflammation took over, and more significantly with 100% than with 30%. This study suggests a biphasic response over time characterized by an initial “permissive oxidation” followed by increased inflammation. The antioxidant protection system seems not to be the leading actor in the first place. The kinetics of enzymatic reactions need to be better studied to establish therapeutic, training, or rehabilitation protocols aiming at a more targeted use of oxygen.