Effect Of Feruloylated Oligosaccharides From Maize Bran On Volatiles And Intermediates During The Maillard Reaction

Feruloylated Oligosaccharides(FOs) has received much attention due to its excellent biological activities. It has been approved by US FDA as Wheat Bran Extract and included in the “Generally Recognized as Safe”(GRAS) list. In this study, FOs was prepared from maize bran and its effects on the volatiles and intermediates produced during the Maillard reaction were investigated. The main conclusions are as follows: 1. Preparation of FOs from maize bran by resin chromatographyFOs was extracted from maize bran by using oxalic acid autoclaving hydrolysis method. The purification efficiency of resin HP-20 and D301 for FOs were compared under both static and dynamic adsorption conditions, and the elution efficiency of different concentration of ethanol was investigated. Results showed that HP-20 was the optimal resin for purifying and 70% ethanol was the optimal concentration for eluting FOs. After purification, the content of total sugars, reducing sugars, total ferulic acid and free ferulic acid FOs were 734.3, 178.9, 93.6 and 5.8 mg/g, respectively and the average degree of polymerization of FOs was 4.1. 2. Effect of FOs from maize bran on volatiles formation during the Maillard reactionThree kinds of Maillard reaction model systems were established by reacting 1 mmol glucose respectively with 1mmol aspartic acid, asparagine, or glutamic acid at 160 ℃ for 15 min, and bakery foods systems were built up by baking dough. Headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry(HS-SPME-GC-MS) was applied to investigate the effect of FOs prepared from maize bran on the formation of volatiles in the three Maillard reaction models and baked dough. Results showed that, in all reaction models, the addition of FOs at 1% and 5% singnificantly increased the formation of furfural and unpleasant flavor compounds including dimethyl disulfide, dimethyl trisu lfide and 2-methoxy-4-vinylphenol, but suppressed the formation of several pleasant flavours, including pyrazines, maltol, nonanal, and cedrol. So, taking into account the adverse effects on the flavor, FOs should be cautiously applied in bakery foods though it is allowed to be added into them without limit. 3. Effect of FOs from maize bran on the formation of α-dicarbonyl compounds during the Maillard reaction at different pH conditionsEffect of FOs on the formation of α-dicarbonyl compounds was investigated in three kinds of Maillard reaction model systems at different pH values(5.0,6.0,7.0 and 8.0); α-dicarbonyl compounds formed in these systems were determined using HPLC after they formed derivatives with o-phenylenediamine. Results showed that FOs from maize bran significantly suppressed the formation of α-dicarbonyl compounds during the Maillard reaction.The maximum inhibition rates of 0.1% FOs for glyoxal in the glucose/aspartic acid, glucose/asparagine and glucose/glutamic acid systems were 79.6%, 73.7% and 77.0%, respectively. The inhibition rates increased with the increase of the addition level of FOs; no glyoxal has been detected after the addition of 3% FOs in all reaction models at pH 8.0s. The inhibition rates of glyoxal were fairly related to pH, and the rates increased when pH rose.The maximum inhibition rates of 0.1% FOs for methylglyoxal in the glucose/aspartic acid, glucose/asparagine and glucose/glutamic acid systems were 59.7%, 79.7% and 66.0%, respectively. When the concentration of FOs rose to 3%, the maximum inhibition rates of methylglyoxal increased to 92.9%, 97.5% and 71.6%, respectively. Similarly, the inhibition rates of methylglyoxal were fairly related to p H, and the rates increased with pH rising.The maximum inhibition rates of 0.1% FOs for 3-deoxyglucosone in the glucose/aspartic acid, glucose/asparagine and glucose/glutamic acid system were 62.9%, 27.9% and 36.0%, respectively. When the concentration of FOs reached 3%, the maximum inhibition rates of 3-deoxyglucosone increased to 94.9%, 94.1% and 79.9%, respectively. Similarly, the inhibition rates of 3-deoxyglucosone were fairly related to pH, and the rates increased with pH rising.The maximum inhibition rates of 0.1% FOs for 2, 3-butanedione in the glucose/aspartic acid, glucose/asparagine and glucose/glutamic acid system were 80.6%, 25.8% and 59.9%, respectively. When the concentration of FOs rose to 3%, the maximum inhibition rates of 2, 3-butanedione increased to 87.8%, 76.4% and 63.9%, respectively. Similarly, the inhibition rates of 2, 3-butanedione were related to pH. The rates increased when pH rose in the glucose/aspartic acid systems, but they decreased with pH rising in the glucose/asparagine systems, and the maximum inhibition rates in the glucose/glutamic systems were in neutral p H condition. 4. Effect of FOs from maize bran on advanced glycation end-products(AGEs) during the Maillard reaction at different pH conditionsThe Maillard reaction model systems were built up by the same way and the AGEs concentration were detected by fluorescence spectrophotometer. Results showed that FOs significantly inhibited the formation of AGEs in these Maillard reaction systems. The additition of FOs at 0.1% and 3% singnificantly suppressed the formation of AGEs in all systems except for pH 5.0 and 6.0 in glucose/aspartic acid system.