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 %.
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.
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.
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.
Deproteinization of natural rubber was achieved in the latex stage. The structure of deproteinized natural rubber (DPNR) was characterized by fourier transform infrared spectroscopy (FTIR). The thermo degradation of DPNR was studied by thermogravimetry analysis (TG) under air atmosphere and nitrogen atmosphere. The kinetic parameters apparent activation energies (Ea) of the thermal decomposition reaction been calculated from the TG curves using the method described by Broido. And the results were compared with the thermo degradation of natural rubber (NR) under the same conditions. The effect of proteins in natural rubber latex on thermal/ thermo-oxidative stability of NR was discussed. The results show that: the absorptions of the proteins in DPNR at 1546 ㎝-1, compared to NR, become significantly weaker, nearly disappear, which indicates most of proteins has been removed from NR. The thermo degradation of DPNR in nitrogen atmosphere is a one-step reaction. The initial degradation temperature (T0) 、the maximum degradation temperature(Tp) and the final degradation temperature(Tf)as well as the Ea of DPNR are higher than those of NR, which indicates that DPNR represents a better thermal stability than NR under nitrogen atmosphere. Thermo-oxidative degradation of DPNR and NR are two-step reaction. The characteristic temperatures (T0, Tp and Tf) of DPNR are lower than those of NR. The Ea during the First Step of Thermooxidative Degradation of DPNR are also lower than those of NR. These results prove that the thermo-oxidative stability of DPNR is worse than that of NR. Protein is the key role to the thermal stability of natural rubber.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.