Lian Zhou Jiang

Antioxidant Activity of Soybean Peptides

This experiment contrasted the hydrolytic effect of SPI among the six different proteolytic ferments and the Alcalase basic protein which can produce the best antioxygen peptide, the optimization technology condition of hydrolytic SPI determined by orthogonally experimentation: concentration of substrate 7.0%, the dozes of enzyme 9000U/g substrate, temperature 52.5°C, pH 8.5, the reaction time 5h. The antioxygen activity of hydrolysis product is researched from the capability of cleaning OH·, the capability of cleaning O2-· and the capability of inhibiting ROO·. After hydrolyze of 5h, the OH· inhibition ratio of the production is 36.43%, the activity of cleaning O2-· of the production is 317.73U/g, the ROO· inhibition ratio of the production is 46.24%.

Effect of Extruding Parameters on Soybean Oil Yield of Enzyme-Assisted Aqueous Extraction Processing

Experiments were carried out to investigate effects of extruding parameters on soybean oil yield extracted with enzyme-assisted aqueous extraction. It was found that extrusion and expansion parameters affected significantly on total soy oil yield. Optimal extrusion and expansion parameters for highest total soy oil yield were obtained using response surface methodology. Effect of extrusion and expansion pretreatment on soy cells was studied using light microscope and transmissive microscope. State of free oil and protein during hydrolysis was observed using light microscope. Ultrasonic assistant ethanol de-emulsification was found the effective method to destabilize the emulsion.

Improvement of Emulsifying Properties of Soybean Protein Isolate through Glycosylation Modification

In order to improve EAI and ESI of Soybean protein isolate (SPI), Glycosylation modification was studied by adding lactose and the operation conditions for modification were established by single factor experiment. On the basis, Box-Behnken model was used to optimize technological conditions, test and analyze the EAI and ESI of modified products under various conditions. The best glycosylation modification was as follows: the augmenter of lactose was 6.9%, reaction temperature was 70.5°C, reaction time was 38.6h, and the EAI and ESI could achieve 0.754 and 24.00 which was 2.32 and 2.67 times of the unmodified SPI. The experiment proved that the modification technology can effectively increase EAI and ESI of SPI.

The Comparison of Amino Acid Content of the Hydrolysate under Extrusion Pretreatment with Non-Extrusion Pretreatment

The extrusion pretreatment was employed in the aqueous enzyme assisted extraction (EAEP) of oil process. The amount of amino acid was detected during the study. Experimental results indicated that the extrusion pretreatment contributed to the increment of free amino acid amount.

The Experimental Study about the Influence of Extrusion System Parameters on Textured Degree of High Moisture Content Fibriform Imitated Meat

The high-emulation meat with 60% ~ 80% moisture content made use of high humidity extrusion technology was prepared with soybean protein isolate, defatted soybean meal and wheat gluten as main raw materials. The effect of extrusion system parameters (extrusion temperature, screw rpm , moisture content and soybean protein isolate content) on product textured degree was studied. Results showed that: the influence of the moisture content on the product textured degree was the most important, and screw speed was less influential. The textured degree of high moisture content fibriform imitated meat increased first and then decreased with the increasing of extrusion temperature, screw rpm, moisture content and soybean protein isolate content. So, better textured degree could be received by increasing the parameters to advisable numerical value, and the product would have an obvious fibroid structure. The conclusion could also be used as a value reference in the production of high-emulation meat of livestock and poultry. At present, we are committed to produced emulation meat with soy protein. High moisture extraction[1] is jointly developed by Clextral Co. France and Pro. Co.Ltd was one way of producing simulation meat. This technology, with special cooling die head twin-screw extruder for main equipment, prepared textured soy protein production at the moisture content of material higher than 45%. It had been discovered that with the increase of moisture content of textured soy protein the textured rate of production would be increased. The elastic, resiliency and fibroid structure would be much more like the animal meat. At present, extrusion of material moisture higher than 60% could not be achieved in the domestic. The twin-screw extruding technology on soy protein with moisture content 60%~80% was studied in this subject. Production condition of high moisture content fibrous imitated meat would be established and technical features would be supplied to domestic extruding equipment through the influence of extruding temperature, material moisture content, screw speed and material composition on soy protein molecular recombination and fibrosis.

The Research on Freeze-Thaw De-Emulsification Technology in Enzyme-Assisted Aqueous Extraction Processing

Experiments were carried out to analysis optimization of freeze-thaw regression model with Response Surface Analysis Method. The optimal response result is: freeze temperature: -18°C, freeze time: 12.5h, thaw temperature: 57°C, released oil yield: 93.16%, total free oil yield rate: 89.28%. The mechanism of demulsification was studied using Micro-imaging, SEM cooling stage, DSC, FTIR spectrometer. DSSP was changed and part of hydrogen bond was broken and α－helix structure conversed to random coil during the freeze process were found the effective freeze-thaw method to destabilize the emulsion.

Effects of pH on Properties of Soy Protein Isolate/Guar Gum Composite Films

The objective of this research was to investigate the effect of pH(7.0, 8.0, 9.0, 10.0) on the properties of soy protein isolate (SPI)/guar gum (GG)composite films casted with 0.2 %(w/v)guar gum polysaccharide, 5.0 %(w/v)SPI, 1.5 %(w/v)glycerol plasticizer, and 4:1(v/v) mixture of distilled water and anhydrous alcohol. Composite membranes from different pH conditions were evaluated from following aspects: tensile strength (TS), elongation at break (EB), water vapor permeability (WVP), water solubility (WS) and surface hydrophobicity(SH)

Optimization of Glycosylating Condition for Soy Protein Isolates and Maltodextrin by Maillard Reaction

The glycation of soy protein isolates and maltodextrin by Maillard wet-heating were evaluated. Glycosylating condition was optimized by the single factor test. The effects of temperature, heating time, protein content, weight ratio of maltodextrin to protein and dextrose equivalents (DE) of maltodextrins (Mds) on the degree of substitution (DS) and browning were investigated. The most optimum conditions are as follows: temperature 90°C, heating time 3h, the protein content 10mg/mL, the weight ratio 2, DE of maltodextrins 9~12. The degree of substitution and browning reaches 14.9% and 0.27 respectively. The aim of this work was to investigate the relationship between the conditions and the degree on the glycation of SPI and Mds.

Antioxidative Capacity of Peptides Isolated from Soybean Meal

Soybean meal was hydrolyzed by Neutrase in research. DPPH radical scavenging rate, hydroxyl radical scavenging rate and reducing power were chosen as the response values. Then the optimal technique was established through a systemic research on the influencing factors, including hydrolysis temperature, time, pH, enzyme amount and substrate concentration. Results show that the soybean meal can be effectively hydrolyzed by Neutrase, and the optimal technique conditions were temperature 40°C, time 4h, pH 7.0, enzyme amount 48,000U/g substrate, and substrate concentration 6%. Under these conditions, reducing power is 0.954.

Changes in Structural Properties of Porcine Myofibrillar Protein Induced by Frozen Storage

Changes in structure property of myofibrillar protein from porcine longissimus dorsi were monitored during 12 months of storage at –5, –18, –26, –35 and –70 °C. With the extended frozen time at the same temperature, Ca2+-ATPase activity, K+-ATPase activity, total sulfhydryl content reactive sulfhydryl content decreased (P < 0.05), surface hydrophobicity (S0-NAS) increased (P < 0.05). Meanwhile, stucture of myofibrillar protein was more susceptible to high frozen storage temperature than low frozen storage temperature. There was markedly loss in band intensity of myosin heavy chain, actin, paramyosin, troponin, and propomyosin from frozen meat within frozen storage.