Effect of the Condition of Spray-Drying on the Properties of the Polypeptide-Rich Powders from Enzyme-Assisted Aqueous Extraction Processing

Enzyme-assisted aqueous extraction processing(EAEP)is an environmentally friendly technology that simultaneously extracts both oil and protein.It has shown to be commercial feasibility for high oil recovery(97%)and favorable protein functionality properties.The present study used soy skim,the liquid co-products obtained using EAEP to produce a polypeptiderich spray-dried powder.The effects of inlet drying air temperature(140℃,160℃,180℃and 200℃),feed flow rate(3,6,9,and 12 m L/min),and solids concentration(25%,30%,35%,and40%)on the properties of the polypeptide-rich powders were investigated.Water activity(aw),color characteristics,bulk density,Carl Index(CI),Water Solubility Index(WSI),micro-morphology,peptide distribution,and antioxidant capacity were significantly affected by different spray-drying parameters.The results of antioxidant capacity test showed that the spray drying conditions significantly affected the antioxidant capacity of the polypeptide-rich powders.The polypeptide molecular weight size and distribution,the composition of the peptide chain,and the crosslinking with other substances could all affect its antioxidant capacity.Overall,good quality polypeptide-rich powders in terms of physicochemical characteristics,micro-morphology,and functional properties can be produced by spray-drying at an inlet temperature of 160℃,a feed flow rate of 6 m L/min,and solids concentration of 35%.

Physicochemical properties of silver carp(Hypophthalmichthys molitrix)mince sausages as influenced by washing and frozen storage

Frozen storage of emulsion-type sausages may be one approach to avoid or reduce the use of sodium nitrite,which is associated with health risks.Silver carp(Hypophthalmichthys molitrix)mince(M_(0))was washed for 1(M_(1))or 3(M_(3))times and the impact of washing on the properties frozen storage(−18℃)during 4 months were determined and results were compared to those of conventional silver carp sausages(Mt).Lipid oxidation,as evidenced by changes in thiobarbituric acid reactive substances and FFAs,took place during storage in the order of M_(0)>M_(1)=M_(3)=Mt with M_(0)being highly oxidized(P≤0.05).Total volatile base nitrogen formed during storage and the ranking for the quality loss was as follows M_(0)>M_(1)>M_(3)=Mt.Washing(M_(1)=M_(3))led to less hardness(P≤0.05).Mt had better redness,while M_(1)and M_(3)led to higher expressible moisture,water release and lightness(P≤0.05).Results indicated the lower sensory and consumer-liking properties of frozen M_(1)and M_(3)sausages.Therefore,washing and frozen storage influenced silver carp mince sausages.

Sea cucumber enzymatic hydrolysates relieve osteoporosis through OPG/RANK/RANKL system in ovariectomized rats

Osteoporosis harms human health and has a variety of causes,among which the imbalance of bone metabolism caused by menopause is an important one.Studies have shown that sea cucumbers have a variety of physiological activities such as anti-inflammation.Sea cucumber enzymatic hydrolysates(SCEH)were prepared and characterized for peptides and polysaccharides,and then the effects on relieving osteoporosis were explored by feeding ovariectomized Sprague-Dawley rats for 90 days.Bone density and microstructure were measured using micro-CT and pathological sectioning.Serum markers for bone metabolism,and inflammation were measured using ELISA kits.Gene transcription and expression of the OPG/RANKL system in bone were measured using qRT-PCR and western blots.Results showed that SCEH could improve the bone density,strength,microstructure and mass,and inhibit the generation of osteoclasts.The abnormally elevated markers for bone resorption,formation and inflammation were reduced with the intake of SCEH.The mRNA and protein expressions of RANKL were also decreased by feeding SCEH,thereby up-regulating the ratio of OPG to RANKL.These results suggested that SCEH could inhibit the bone resorption by inhibiting the NF-κB pathway related to osteoclast generation via the down-regulation of both the RANKL level and inflammatory response,and also improve the balance of bone metabolism,thus obtaining the effects of increasing bone density and relieving osteoporosis.SCEH with a medium-dose(1000 mg/kg body weight)had the best remission effect and could be used as a potential starting material to develop healthy foods that can assist in treating osteoporosis.