ABSTRACT
This work aims to use defatted rice bran albumin (RBA) for delivering epigallocatechin gallate (EGCg). The mode of RBA particle size shifted from 142 nm to 164 nm upon interaction with EGCg. Hydrophobic interaction is the major force between EGCg and RBA resulted in the formation of EGCg-RBA complex based on fluorescence quenching. Upon incorporation into RBA, the recovery of EGCg in pH 7.4 phosphate buffer was elevated by 2 folds. The recovery of EGCg in EGCg-RBA was 18.9% after 2 h intestinal digestion, being higher than 7.6% of native EGCg. The pretreatments of HT-29 cells with EGCg, RBA and EGCg-RBA significantly repressed the transcriptional activation of mitogen-activated protein kinase 14, nuclear transcription factor-κB, and activators of transcription 3 as stimulated with interleukin-1ß afterwards, leading to attenuated expressions of corresponding downstream genes. Antioxidant ability importantly functioned in anti-inflammation. RBA is a promising vehicle with inherent anti-inflammatory property for stabilizing and delivering EGCg.
Subject(s)
Albumins/chemistry , Catechin/analogs & derivatives , Oryza/metabolism , Antioxidants/metabolism , Catechin/chemistry , Catechin/pharmacology , HT29 Cells , Humans , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Mitogen-Activated Protein Kinase 14/genetics , Mitogen-Activated Protein Kinase 14/metabolism , NF-kappa B/genetics , NF-kappa B/metabolism , Particle Size , Transcriptional Activation/drug effectsABSTRACT
This study investigated the effect of lactic acid bacteria (LAB) fermentation on the chemical profile of autoclaved broccoli puree, using 7 broccoli-derived LAB isolates (named F1-F5, BF1 and BF2). The total concentrations of glucosinolates (glucoiberin, progoitrin and glucoraphanin) and 10 major phenolics significantly increased from trace level and 289⯵g total phenolics/g dry weight (DW) respectively in autoclaved broccoli to 55 to â¼359⯵g/g DW and 903 to â¼3105⯵g/g DW respectively in LAB fermented broccoli puree. Differential impacts of LAB isolates on the chemical composition of autoclaved broccoli were observed, with the major differences being the significant increase in phloretic acid after fermentation by F1-F5 and an elevated glucoraphanin level in ferments by F1 and BF2. LAB fermentation is a promising way to increase the content of glucosinolates and polyphenolic compounds in broccoli, making the ferments attractive for use as functional ingredients or as a whole functional food.
Subject(s)
Brassica/metabolism , Glucosinolates/metabolism , Lactobacillales/metabolism , Phenols/metabolism , Sugars/metabolism , Biotransformation , Brassica/chemistry , Brassica/microbiology , Fermentation , Imidoesters/metabolism , Oximes , Principal Component Analysis , Spectroscopy, Fourier Transform Infrared , SulfoxidesABSTRACT
Rice bran protein isolate (RBPI) was prepared from defatted rice bran and used to deliver tea catechins. RBPI had the high adsorption selectivity for tea catechins over caffeine. The adsorption characteristics of tea catechins onto RBPI were determined over a range of time (0-300min), concentration (0.25-3.5gL-1) and temperatures (5°C, 20°C and 35°C). The adsorption kinetic data of EGCg and total catechins (TC) onto RBPI showed excellent fitness with the pseudo-second-order model, indicating that chemisorption is the dominating process. Langmuir and Freundlich models adequately described the isothermal adsorption of tea catechins onto RBPI, and the maximum adsorption of EGCg and TC were achieved at 5°C. SDS-PAGE profiles indicated that globulin and albumin were the major soluble proteins in RBPI to bind tea catechins. Fourier transforms infrared spectroscopy analysis showed that the protein secondary structures of RBPI were altered upon interaction with catechins, with a great increase in random coil and ß-antiparallel, a minor increase in α-helix and a reduction in large loop and turn. Binding tea catechins to RBPI respectively increased the recovery% of EGCg and TC from 10.5% and 17.7% to 29.5% and 31.6% after in vitro intestinal digestion. Thus, RBPI is a promising food matrix for delivering tea catechins to gastrointestinal tract.
Subject(s)
Catechin/metabolism , Digestion , Oryza/chemistry , Plant Proteins/metabolism , Seeds/chemistry , Adsorption , Biophysical Phenomena , Caffeine/metabolism , Catechin/analogs & derivatives , Gastrointestinal Tract/metabolism , Kinetics , Plant Proteins/isolation & purification , Spectroscopy, Fourier Transform Infrared , TemperatureABSTRACT
UNLABELLED: The potential of rice bran as a bioabsorbent for tea catechins was examined. Defatted rice bran had the highest adsorption capacity for tea catechins and the best selectivity for (-)-epigallocatechin gallate over total catechins among water-washed rice bran and untreated rice bran. The adsorption characteristics of tea catechins onto defatted rice bran were determined over a range of concentration (0.5 to 2.5 g/L) and temperatures (10, 25, and 45 °C). The adsorption of tea catechins onto defatted rice bran showed excellent fitness with the pseudo-second-order model at different temperature. Both the Langmuir and Freundlich models adequately describe the isothermal adsorption of tea catechins onto defatted rice bran. The adsorption of total catechins on rice bran decreased from 10 to 25 °C, whereas was greatly enhanced at 45 °C. The adsorption system of bioadsorbent with multiconstituents may not be as simple as the single-force-driving adsorption system. Protein and cellulose are the main contributors to the adsorption of tea catechins on defatted rice bran. PRACTICAL APPLICATION: Rice bran is regarded as a good fibre source that can be added to various food products and health supplements, which is a potential biocarrier for bioactives. Our study showed that defatted rice bran had a high affinity for tea catechins but caffeine, and provided a promising way for selective enrichment of catechins on defatted rice bran under practical condition. Protein and cellulose are the main contributors to the adsorption of tea catechins on defatted rice bran.