Effect Of Germination On The Allergenicity Of Soybean Protein

Soybean sprouts are valuable dietary supplements that may promote health and well-being in many places of the world,particularly in rural areas among Asian countries,where seasonal fruits and vegetables are unavailable all-year-round.Unfortunately,intake of soy-containing food can cause immunological symptoms in soy-allergic individuals,and the prevalence of soybean allergy is approximately 1%to 6%in infants.Research shows that different germination conditions,pressure,light and other physical factors could influence the soybean sprouts in a variety of biological ingredients,change the nutritional value.Germination has been identified as an inexpensive and effective technology for improving the nutritional quality of soybean.This study was focused to evaluate the effects of germination in combination with hydrolysis,ultrasound and high hydrostatic pressure on the allergenic of soybean protein.Meanwhile,we also investigate the biochemical and physiological characters of soybean sprout to provide scientific evidence for future development of functional edible sprouts with ultrasound and high hydrostatic pressure.The results of this study were shown as following.1.Germination temperature and time affected the allergenicity of soybean protein during germination.It was suggested that at 30 ?,after 4 d of germination resulted in a lowest allergenicity of soybean protein.Meanwhile,we assessed the allergenicity characteristics of germinated soybean protein in a BALB/c mouse model,which included an evaluation of clinical signs of anaphylaxis and objectivemeasurements of antibody levels,mMCP-1,morphological structure of duodenum and cytokines.The results suggested that germinated soybean protein sensitization leaded to a milder allergenic response than soybean protein sensitization.2.In this study,we confirmed that Alcalase hydrolysis of germinated soybean protein resulted in a decrease in its allergenicity.The allergenicity of germinated soybean protein hydrolysate prepared by Alcalase at pH8.0 for 90 min was lowest.However,the hydrolysate had the residual sensitizing capacity in mice.3.The combined of germination and enzymatic hydrolysis were confirmed to effectively improve the quality of soybean protein.Solubility,emulsification activity index,emulsion stability index,and foaming capacity of soybean protein were remarkably improved by the combination treatMent,but the total essential amino acid content,the chemical score and the essential amino acid index decreased.Besides,the in vitro protein digestibility and protein efficiency ratio of soybean protein were improved.Futhermore,the modified soybean protein had better swallowing properties.4.Ultrasound treatment(100W,200W,300 W)decreased the free sulfhydryl content of soybean protein.No significant change was observed in the protein electrophoretic patterns by SDS-PAGE.However,surface hydrophobicity and protein solubility of soybean protein were all increased with ultrasound treatment.Secondary structure analysis by circular dichroism indicated higher a-helix and lower ?-turn,no changes in random coil and ?-sheet in soybean protein with ultrasound treatment.5.Ultrasound treatment(100W,200W,300 W)led to parenchyma cell wall thickening,increased the cell volume,and created the holes on the tissue surface.Meanwhile,it also led to a significant increase in the activities of catalase(CAT)and superoxide dismutase(SOD).However,the concentrations of malondialdehyde(MDA)and O-2 decreased.6.Ultrasound treatment(100W,200W,300 W)increased germination rate,sprout length,and GABA content of soybean sprouts.No significant change was observed in protein patterns.The IgE-binding,lipoxygenase isozyme activity,and trypsin inhibitor content of soybean sprouts showed a power-dependent decrease after the seeds were exposed to ultrasound.As for the isoflavone content,daidzin and genstin contents markedly decreased,whereas,daidzein and genstein contents increased compared with those of the untreated sample.7.High hydrostatic pressure(HHP)treatment in the ranges of 100-500 MPa led to a slight but gradual decline in free SH content.The solubility and hydrophobicity of soybean proteins increased sharply from 100 to 200 MPa,while they were gradually decreased upon the further increase of pressure.For the secondary structures upon the HHP treatment,the ?-helix and ?-sheets contents of soybean proteins decreased,while the random coil contents increased.The SDS-PAGE showed that HHP treatment of 100 to 200 MPa could dissociated the proteins,breaking the aggregates into smaller units,while the treatment ranging from 300 to 500 MPa could induced the proteins aggregated into big units.Moreover,the ELISA revealed that the IgE-binding of soybean proteins after HHP treated with 200 MPa decreased 61.7%compared to the untreated group.8.HHP treatment(0-300 MPa)led to the epidermal of soybean seed wrinkled,the membranes became leaked.Meanwhile,HHP treatment also led significant increase in the concentrations of malondialdehyde(MDA)and O-2,but the activities of catalase(CAT)and superoxide dismutase(SOD)decreased significantly.9.HHP treatment(0-300 MPa)impaired the germination capability of soybean seeds.It decreased the germination rate and sprout length of soybean sprouts.The IgE-binding and trypsin inhibitor content of soybean sprouts showed a power-dependent decrease after the seeds were exposed to ultrasound.Whereas,lipoxygenase isozyme activity increased compared with those of the untreated sample.Our study suggested that ultrasound could be utilized as a novel processing tool to reduce the allergenicity of sprouts-based food,such as soybean.On the basis of these findings,the potential mechanism still needs further study.10.Germination could reduce the allergenicity of soybean protein.However,germination combined with enzymatic hydrolysis further reduced the allergenicity of soybean protein.Ultrasound treatment(100W,200W,300 W)will be a novel approach to improve the edibility and nutritional quality of soybean sprouts.Meanwhile,ultrasound could be utilized to reduce the allergenicity of soybean sprouts.HHP treatment(0-300 MPa)impaired the germination capability of soybean seeds.However,the allergenicity of soybean sprouts reduced after HHP treatment.