Hai Sheng Tan

Research on Chemical Composition and Ensiling Characteristics of Banana Stems and Leaves

In order to investigate the nutritive and ensiling characteristics of banana stems and leaves, the chemical compositions of banana stems and leaves were analyzed and the effects of additives on fermentation quality were measured. The research results showed: Banana stems and leaves had high fiber content (stem>58% DM, leaf >72% DM), nitrogen free extract content (>50% DM), and water soluble carbohydrate contents (WSC>5% DM), with certain nutritive value. Tannins of banana stem and leaf were 0.11% DM and 0.24% DM. There were lactic acid bacteria (>105cfu/g FM) in the banana stems and leaves; they might be well preserved with some treatments.

Study on Microbial Flora's Change and Fermentation Quality in Ensiling of Banana Stems and Leaves

Four samples of banana stems and leaves were prepared, which were processed through adding no additives, adding molasses, adding lactic acid bacteria (LAB), and adding both LAB and molasses respectively. In order to find out the regular pattern of microbial flora, microbial flora of each sample was analyzed during ensiling. It was found out that growth of LAB reached its peak of 6.4×107～7.8×109 CFU/g FM in the 6th day of ensiling, growth of aerobic bacteria reached its peak of 2.8×104～5.6×104 CFU/g FM in the 3rd day of ensiling, and growth of yeast reached its peak of 8.6×104～5.8×106 CFU/g FM in the 3rd day of ensiling. All of the samples with different way of processing showed the same trend that growth of microbial flora number were increased gradually and then decreased. It were also found out that decrease of pH value had relation with LAB number, and decrease of pH value were lagged behind the peak number of LAB, and number of aerobic bacteria and yeast were decreased with reproducing of LAB and decline of pH value. Nutrition constituent of forage made of banana stems and leaves was as follows: Dry matter 32.27%～33.59%，Crude protein 7.42%～8.16%, Acid detergent fiber 38.21%～41.43%. Quality of silage added with molasses, LAB and both molasses and LAB were better than that with no additives.

Mechanical Properties of Natural Rubber and Chloroprene Rubber Latex Blends

The effects of the ratios of natural rubber latex (NRL)and chloroprene rubber latex(CRL) and the type of compatibilizer on physical and mechanical properties of latex film were researched.The oil resistance of vulcanized latex film was tested. The compatibility of the latex blends was also analyzed by TG/DTG method.The results showed that properties of latex film were best when ratio of NRL/CRL was 75/25. As the CRL content increased, oil resistance of latex film was improved. Epoxidized natural rubber latex improved compatibility of NRL and CRL blends.

Preparation of Polymer Composite Latex via Miniemulsion Polymerization: Fluorinated Acrylate as Co-Stabilizer and Functional Modifier

The silica/polyacylate composite latex was prepared via miniemulsion polymerization. Fluorinated acrylate monomer was used the co-stabilizer and hydrophobic modifier. The effect of fluorinated acrylate on stability of the composite latex was compared with the traditional co-stabilizer. The composite latex and the resultant film were characterized by Fourier transformation infrared spectroscopy, Dynamic laser scattering, Water contact angle. Fluorinated acrylate can stabilize the miniemulsion polymerization as the co-stabilizer and the resultant film has good durability of hydrophobicity under high moisture environments.

Diversity and Application of Lactic Acid Bacteria from Papaya

Four lactic acid bacteria (LAB) strains named MGP1, MGP2, MGP15 and MGP17 were separated from papaya of Hainan province, which were identified bacterially using the classical classification and the sequences of 16S rRNA. The results show that MGP1, MGP2, MGP15 and MGP17 are Weissella confusa, Lactococcus lactis subsp. lactis, Leuconostoc pseudomesenteroides and Lactobacillus pentosus. The strain with strongest acid production capability is MGP17. Besides we have applied MGP2, MGP15 and MGP17 in papaya pickle, and we find that pickle fermented with mixed strains obviously shortens fermentation time and reduces the nitrite content.

Optimization of Inferior Banana Saccharifiction with Response Surface Methodology

A study was implemented, referring to inferior banana saccharification on the glycosylation interaction of α-amylase and Aspergillus niger. During the experiment of defective banana saccharification, the interaction of the additive amount of α-amylase, Aspergillus niger, initial pH, saccharification temperature and saccharification time was analyzed. On the basis of confirmation of solid-to-liquid ratio of inferior bananas, saccharification temperature and additive amount of α-amylase, the interaction of the additive amount of Aspergillus niger, the initial pH and saccharification time in the different response surface was experimented and analyzed, then the optimal proportions of glycosylation saccharifying inferior bananas were as follows: Aspergillus niger 0.5%, saccharification time 7 h, pH 4.61. Brix of reducing sugar is 16.693 mg/g.

Microbial Flora Variation in Process of Jackfruit Peel Ensiling

Three samples of jackfruit peel were prepared, which were processed through adding no additives, adding lactic acid bacteria (LAB), and adding both LAB and pectinase respectively. In order to find out the regular pattern of microbial flora, microbial flora of each sample was analyzed during ensiling. It was found out that growth of LAB reached its peak of 1.2×109～4.5×109 CFU/g FM in the 7th day of ensiling, growth of aerobic bacteria reached its peak of 3.5×105～1.8×106 CFU/g FM in the 3rd day of ensiling, and growth of yeast reached its peak of 2.8×105～4.6×105 CFU/g FM in the 3rd day of ensiling. All of the samples with different way of processing showed the same trend that growth of microbial flora number were increased gradually and then decreased. It were also found out that decrease of pH value had relation with LAB number, and decrease of pH value were lagged behind the peak number of LAB, and number of aerobic bacteria and yeast were decreased with reproducing of LAB and decline of pH value. Quality of silage added with LAB, and both pectinase and LAB were better than that with no additives.

Research on the Inclusion Complex of Astaxanthin

Taking β-cyclotextrin and gelatin as wall materials, study of inclusion was processed on astaxanthin. It was shown in the study that β-cyclotextrin and gelatin at the ratio of 4 to 1 was found to be the best wall material for inclusion complex. The optimal conditions of inclusion were established by the RSM experiment: when the amount of wall material was 0.4 g/g yeast, temperature 40°C, time 1.2 h, the inclusion rate could reach 81.03%. The characterization of the inclusion complex was confirmed by different temperatures and light, the result shows that the inclusion complex could improve the stability of astaxanthin. The inclusion complex was stored in dark at 4°C for 60 days, the residual rate of astaxathin could reach 95% and more stable than that before inclusion by 35%.

Astaxanthin Production by Phaffia Rhodozyma Fermentation of Pineapple Peel Substrate

Pineapple peel as main material was fermented with Phaffia rhodozyma to produce astaxanthin. Using the Box-Behnken design, the effects of sugar content, initial pH and nitrogen content were studied with the yield of astaxanthin as response value, which was evaluated to optimize the fermentation conditions of astaxanthin production. The optimal fermentation conditions have been reached by the study: sugar content was 36.3 g/L, the initial pH was at 5.85 and nitrogen content was 8 g/L. By validation test, the astaxanthin yield under the optimal condition, which was basically corresponded to the model prediction, was 97.11 %.

Study on Thermal and Mechanical Properties of Natural Rubber Latex Modified by Trichlorobromomethane

Natural rubber latex (NRL) modified by holgonated addition with trichlorobromomethane was prepared. The thermal properties of modified NRL were analyzed by thermogravimetric analysis (TG/DTG),differential scanning calorimetry (DSC) and dynamic mechanical analysis(DMA). The results showed that the thermal stability of modified NRL was lower than NRL and the thermal degradation of modified NRL was two-stage decomposition. With increasing of stress frequency, loss modulus and storage modulus of latex increased,while loss modulus and storage modulus of modified latex decreased,compared with NRL.