Li Na Yu

Evaluation of Physicochemical and Antioxidant Properties of Peanut Protein Hydrolysate

Peanut protein and its hydrolysate were compared with a view to their use as food additives. The effects of pH, temperature and protein concentration on some of their key physicochemical properties were investigated. Compared with peanut protein, peanut peptides exhibited a significantly higher solubility and significantly lower turbidity at pH values 2–12 and temperature between 30 and 80°C. Peanut peptide showed better emulsifying capacity, foam capacity and foam stability, but had lower water holding and fat adsorption capacities over a wide range of protein concentrations (2–5 g/100 ml) than peanut protein isolate. In addition, peanut peptide exhibited in vitro antioxidant properties measured in terms of reducing power, scavenging of hydroxyl radical, and scavenging of DPPH radical. These results suggest that peanut peptide appeared to have better functional and antioxidant properties and hence has a good potential as a food additive.

Antioxidant Activity and Total Phenolics of Broussonetia papyrifera Flower Extracts

Ethanol and water crude extracts from the flower of Broussonetia papyrifera were investigated for their antioxidant capacity in four different assays, namely, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, chelation of metal ions (Fe2+), reducing power and inhibition activity of lipid peroxidation in a linoleic acid emulsion system. Among the two extracts, the ethanolextract from B. papyrifera flower showed the most potent radical scavenging activity in each assay, showing 62.88.9% (at 5 mg/ml) in the DPPH radical scavenging method (at 6 mg/ml) and 61.15% of chelation Fe2+- activity. Total phenolics in the water extracts were higher than that of the ethanol ones. Positive correlations were found between total phenolic content in the B. papyrifera flower extracts and their antioxidant activities. B. papyrifera flowers may have potential as natural antioxidants.

Purification and Characterization of a Natural Lectin from the Seed of Peanut Arachis hypogaea

A natural lectin from the seed of peanut Arachis hypogaea was purified by singlestep affinity chromatography using galactoside-coupled agarose. This lectin was named PN-L and its inactive form had a molecular mass estimate of 29 kDa. The lectin PN-L was detected for agglutinating activity, glycoinhibiting action and thermostability. The influence of pH on those activities was also tested. The results showed that PN-L could not agglutinate three kinds of human erythrocytes. But it showed a strong affinity for human A/B/O erythrocytes (RBC) by neuraminidase treated. Agglutinating activity of PN-L to neuraminidase treated human O erythrocytes was inhibited by lactose , raffinose, melibiose and D-galactose. The agglutinating activity of peanut seed lectin was inhibited at temperatures greater than 55 and at a pH less than 5 or greater than 11.

Study on the Key Environmental Factors Aspergillus flavus Growth and Aflatoxin Production

Single factor and Plackett-Burman design were used to determine the key environmental factors for Aspergillus flavus growth and aflatoxin production. The results showed that the key factors were culture time, moisture content. So Controling of moisture was crucial for Aflatoxin contamination prevention and control.

Membrane Separation and Antioxidant Activity Research of Peanut Peptides

High temperature peanut meal was fermented by double strains with solid-stated fermentation, using fermented product dissolved in water and via membrane separate, then obtained four molecular weight distribution(MWD), which were 10kDa. Using four MWD fermentation peptides do experimenting, separated, that is hydroxyl radical-scavenging, DPPH radical-scavenging, reducing power and ferrous ion-chelating, and compared with GSH, it shown that the peptides of 3kDa~10kDa MWD fermentation peptides have the max antioxidant activity, the second was the percolator of >10kDa MWD fermentation peptides, then was the peptides of 1kDa~3kDa MWD fermentation peptides and <1kDa MWD fermentation peptides had the least activity.

Studies on Stability of Peanut Mango Milk

The choice and consumption of emulsifier and stabilizer are one of the main factors affecting stability for peanut mango milk. The stabilizer of mango peanut milk was guar gum, the dosage was 0.15%; The optimum emulsifier was the mixture of sucrose fatty acid ester , monoglyceride and polyglycerol fatty acid ester(1:1:1), the dosage was 0.24%.The study developed a nutrient-rich, stable state of the organization of peanut mango milk.

Chemical Composition of Broussonetia Papyrifera Flowers

Corolla and receptacle of Broussonetia papyrifera from South China were analyzed separately for chemical composition. In this plant’s corolla，the crude protein, crude fat and carbohydrates were 7.08％, 3.72％ and 64.73% respectively in dry weight. In the receptacle, the crude protein, crude fat and carbohydrates were 4.75％, 8.08％ and 67.03% respectively. Unsaturated fatty acids concentration was 68% of total fatty acids. The percentage of the essential amino acids (EAAs) in total amino acids was 34.52%in corolla and 27.96% in receptacle. Furthermore，many mineral celements composition and vitamins are rich in B. papyrifera flowers. In corolla, calcium is 10015 mg/kg, magnesium is 1989.6 mg／kg, zinc is 62.6 mg／kg, iron is 306.6 mg／kg, VE is 1.35mg/100g．These results suggest that, the fiowers could be used in dietary supplements preparations or as food additives.

Technology Optimization on Preparation of Peanut Antioxidant Peptides by Bacillus Subtilis Solid State Fermentation Method

The purpose of this paper is to investigate the preparation of peanut antioxidant peptides by Bacillus subtilis solid state fermentation method and to provide a theoretical basis for further investigating deep processing products of fermentation peanut meal. The preparation technics for peanut antioxidant peptides optimized with the soluble nitrogen concentration of peptides, 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) and hydroxyl free radicals scavenging rates of fermentation broth as the indexes of investigation including the cell age was 20h, bacterial suspension volume was 3.0mL, fermentation temperature was 40°C, nutrient salt solution was 15mL, the fermentation time was 42h, water bath temperature was 45°C, and water bath time was 3h. The research shows that IC50 values for peptides scavenging of DPPH, hydroxyl and superoxide anion free radicals, iron and copper ion chelating rates, lipid peroxidation inhibiting rate, iron and molybdenum reducing activity were 3.48mg/mL, 6.24mg/mL, 2.06mg/mL, 0.54mg/mL, 1.19mg/mL, 4.56mg/mL, 9.58mg/mL and 2.17mg/mL, respectively.

The Anti-Aspergillus Flavus Activity of Composite Coating Using Lemon Aldehyde and Chitosan

In order to inhibit the contamination of peanut in the storage and transportation process, the research on the anti-Aspergillus flavus of the composite coating of the lemon aldehyde and chitosan was studied. The optimum formula of the coating was determined by orthogonal test. The optimum formula was that the concentration of chitosan, 6mg/ml, 0.01mg/ml, glycerol concentration of 9mg/ml. Using this formula, the growth of Aspergillus niger could be significantly inhibited.

The Extraction of Peanut Protein Peptone Hydrolysate from Cold Pressed Peanut Meal by Papain

This paper studied the extraction of peanut protein peptone hydrolysate from cold pressed peanut meal by papain to provide a theoretical basis on peanut meal special microorganism culture makings products for further research. The study use orthogonal test method to optimize the method of papain preparation of peanut peptone, the best preparation conditions were: enzymolysis temperature 55 °C, pH7.5, substrate concentration 3%, the amount of enzyme 6%, enzymolysis time 6 hours. The Protein yield was 52.02% and the content of amino nitrogen was 0.772 mg %by this perparation condition.