RESUMEN
Orange juice (OJ) flavanones are bioactive polyphenols that are absorbed principally in the large intestine. Ingestion of probiotics has been associated with favorable changes in the colonic microflora. The present study examined the acute and chronic effects of orally administered Bifidobacterium longum R0175 on the colonic microflora and bioavailability of OJ flavanones in healthy volunteers. In an acute study volunteers drank OJ with and without the microencapsulated probiotic, whereas the chronic effects were examined when OJ was consumed after daily supplementation with the probiotic over 4 weeks. Bioavailability, assessed by 0-24h urinary excretion, was similar when OJ was consumed with and without acute probiotic intake. Hesperetin-O-glucuronides, naringenin-O-glucuronides, and hesperetin-3'-O-sulfate were the main urinary flavanone metabolites. The overall urinary excretion of these metabolites after OJ ingestion and acute probiotic intake corresponded to 22% of intake, whereas excretion of key colon-derived phenolic and aromatic acids was equivalent to 21% of the ingested OJ (poly)phenols. Acute OJ consumption after chronic probiotic intake over 4 weeks resulted in the excretion of 27% of flavanone intake, and excretion of selected phenolic acids also increased significantly to 43% of (poly)phenol intake, corresponding to an overall bioavailability of 70%. Neither the probiotic bacterial profiles of stools nor the stool moisture, weight, pH, or levels of short-chain fatty acids and phenols differed significantly between treatments. These findings highlight the positive effect of chronic, but not acute, intake of microencapsulated B. longum R0175 on the bioavailability of OJ flavanones.
Asunto(s)
Citrus sinensis/química , Flavanonas/farmacocinética , Probióticos/administración & dosificación , Administración Oral , Adolescente , Adulto , Anciano , Bifidobacterium/fisiología , Disponibilidad Biológica , Composición de Medicamentos , Femenino , Flavanonas/administración & dosificación , Jugos de Frutas y Vegetales , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
The consequences of ultrasonic pre-treatment using low (40 kHz) and medium (270 kHz) frequency (40 kHz followed by 270 kHz) on the degradation of wheat chaff (8 g 100ml(-1) acetate buffer, pH 5) were evaluated. In addition, the effects of the ultrasonic pre-treatment on the degradation of the wheat chaff when subsequently exposed to enzyme extracts from two white rot fungi (Phanerochaete chrysosporium and Trametes sp.) were investigated. Pre-treatment by sequential low and medium frequency ultrasound had a disruptive effect on the lignocellulosic matrix. Analysis of the phenolic-derived volatiles after enzymatic hydrolysis showed that biodegradation with the enzyme extract obtained from P. chrysosporium was more pronounced compared to that of the Trametes sp. The efficacy of the ultrasonic pre-treatment was attributed to increased enzyme accessibility of the cellulose fibrils due to sonication-induced disruption of the plant surface structure, as shown by changes in the microstructure.
Asunto(s)
Lignina/química , Lignina/metabolismo , Phanerochaete/enzimología , Trametes/enzimología , Triticum/química , Biodegradación Ambiental , Sonicación , Triticum/metabolismoRESUMEN
The influence of EDTA on lipid oxidation in sugar beet pectin-stabilized oil-in-water emulsions (pH 6, 15% oil, wet basis), prepared from fish oil (FO) and fish oil-extra virgin olive oil (FO-EVOO) (1:1 w/w), as well as the spray-dried microcapsules (50% oil, dry basis) prepared from these emulsions, was investigated. Under accelerated conditions (80 °C, 5 bar oxygen pressure) the oxidative stability was significantly (P < 0.05) higher for FO and FO-EVOO formulated with EDTA, in comparison to corresponding emulsions and spray-dried microcapsules formulated without EDTA. The EDTA effect was greater in emulsions than in spray-dried microcapsules, with the greatest protective effect obtained in FO-EVOO emulsions. EDTA enhanced the oxidative stability of the spray-dried microcapsules during ambient storage (~25 °C, a(w) = 0.5), as demonstrated by their lower concentration of headspace volatile oxidation products, propanal and hexanal. These results show that the addition of EDTA is an effective strategy to maximize the oxidative stability of both FO emulsions and spray-dried microcapsules in which sugar beet pectin is used as the encapsulant material.
Asunto(s)
Beta vulgaris/química , Química Farmacéutica/métodos , Aceites de Pescado/química , Pectinas/química , Aceites de Plantas/química , Cápsulas/química , Química Farmacéutica/instrumentación , Estabilidad de Medicamentos , Ácido Edético/química , Emulsiones/química , Aceite de Oliva , Oxidación-ReducciónRESUMEN
Protein-reducing sugar conjugates are formed by the naturally occurring Maillard reaction, otherwise known as glycation. The Maillard reaction products (MRP) formed can provide novel and/or improved functionality compared to the unmodified protein. Understanding the chemistry of the Maillard reaction, the physicochemical properties of its products, and, more importantly, the inter-relationships between these properties and the specific functionality of a given MRP will help to define the potential of MRP as food ingredients in their own right. Recently, electrospray ionization-mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) have acquired a leading role in the structural characterization of proteins. The ability of these techniques to provide detail about the nature and extent of protein modifications at a molecular level as well as conformational information provides new insight into the glycation process. This article reviews the role that ESI- and MALDI-MS have played in advancing our understanding of the glycation of milk proteins.
Asunto(s)
Glicosilación , Proteínas de la Leche/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Fenómenos Químicos , Análisis de los Alimentos/métodos , Glicoconjugados , Reacción de Maillard , Espectrometría de Masa por Ionización de Electrospray/métodosRESUMEN
This study investigates the potential of Fourier transform infrared spectroscopy (FTIR) to monitor glycation-induced changes in protein structure. Aqueous solutions of sodium caseinate and glucose (1:2 w/w, pH 6.7) were heated at 90 degrees C for 0, 10, 20, 40 and 60 min. Evidence for caseinate glycation was obtained by mass spectrometry techniques (electrospray (ESI) and matrix-assisted laser desorption ionisation (MALDI)). FTIR was able to discriminate between glycated and non-glycated sodium caseinate, when the data were analysed by multivariate statistical methods; principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA). The techniques used were complementary and provided different levels of information about the glycated samples.
Asunto(s)
Caseínas/química , Tecnología de Alimentos , Espectrometría de Masas/métodos , Espectroscopía Infrarroja por Transformada de Fourier/métodosRESUMEN
A method using high-performance liquid chromatography with UV and electrospray ionization mass spectrometry detection was developed for monitoring the alpha-dicarbonyl compound profiles generated from nonenzymatic browning using o-phenylenediamine (OPD) as a trapping agent. The alpha-dicarbonyl compounds were generated by the "dry" reaction of sodium caseinate and lactose heated at various relative humidities (RHs). The proportions of alpha-dicarbonyls formed were different for samples heated at low, intermediate, and high RHs. This study shows that relatively large amounts of 3-deoxypentosulose and galactosyl 2-pentosulose are produced under high RHs, while galactosyl hexosulose and 1,4-dideoxyhexosulose are elevated under low RH conditions. Both caramelization and Maillard reaction pathways contributed to the generation of alpha-dicarbonyls.
Asunto(s)
Caseínas/química , Calor , Lactosa/química , Reacción de Maillard , Cromatografía Líquida de Alta Presión , Humedad , Espectrometría de Masa por Ionización de ElectrosprayRESUMEN
Proteins are widely utilized to add functional properties, such as gelling and emulsification to foods. These attributes depend on a number of factors such as molecular structure of the protein, the pH, and the composition of its chemical environment. There is substantial evidence to suggest that the functional properties of food proteins can be further improved by derivatization. Covalent bonding of proteins to polysaccharides and smaller reducing sugars via the Maillard reaction has been shown to alter the functionality of proteins without requiring the addition of chemical reagents. Establishment of a technologically feasible method for preparing the conjugates and optimization of the processing conditions, however, is needed to promote their development as functional food ingredients. This paper provides a state-of-the-art contribution to the impact of the Maillard reaction on protein functionality. It presents a deeper understanding of the influence of processing conditions and reactant formulation on improving desirable properties of proteins. In particular attention is given to how potential improvements could be achieved in the emulsifying, textural, and solubility properties of proteins to add value to commodity food ingredients. Elements that are considered to be critical to the design of functional Maillard conjugates are highlighted and suggestions proposed to facilitate progress in this area.