Study on the Degreasing of Sheep Skin Using Subcritical Fluid Extraction

Degreasing is one of the important processes for the production of leather and fur. This study aimed to develop a degreasing method using subcritical n-pentane. Sheep skin was chosen as raw skin for this investigation. The best possible combination of degreasing parameters was found using single factor experiment and response surface methodology. The effects of temperature and pressure on the degreasing efficiency were evaluated further with histological analysis. The results showed that the optimum degreasing parameters were a degreasing time of 58 min, pressure of 0.45 MPa, temperature of 41.0°C and thus yielded a degreasing rate of 52.46％ theoretically and 51.46% experimentally. Histological sections showed that the degreasing effect of subcritical n-pentane was quite significant and the lipid droplets around the hair follicles were dramatically reduced. It has been proven that subcritical n-pentane degreasing is an effective technique for sheep skin degreasing.

Subcritical Methanol Extraction of the Stone of Japanese Apricot Prunus mume Sieb. et Zucc.

The pits of Japanese apricot, Prunus mume Sieb. et Zucc., which are composed of stones, husks, kernels, and seeds, are unused by-products of the processing industry in Japan. The processing of Japanese apricot fruits generates huge amounts of waste pits, which are disposed of in landfills or, to a lesser extent, burned to form charcoal. Mume stones mainly consist of cellulose, hemicellulose, and lignin. Herein, we attempted to solubilize the wood-like carapace (stone) encasing the pit by subcritical fluid extraction with the aim of extracting useful chemicals. The characteristics of the main phenolic constituents were elucidated by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) analyses. The degrees of solubility for various treatments (190 °C; 3 h) were determined as follows: subcritical water (54.9%), subcritical 50% methanol (65.5%), subcritical 90% methanol (37.6%), subcritical methanol (23.6%), and subcritical isopropyl alcohol (14.4%). Syringaldehyde, sinapyl alcohol, coniferyl alcohol methyl ether, sinapyl alcohol methyl ether, 5-(hydroxymethyl)-2-furfural, and furfural were present in the subcritical 90% methanol extract. Coniferyl and sinapyl alcohols (monolignols) are source materials for the biosynthesis of lignin, and syringaldehyde occur in trace amounts in wood. Our current findings provide a solubilization method that allows the main phenolic constituents of the pits to be extracted under mild conditions. This technique for obtaining subcritical extracts shows great potential for further applications.

Ultrasound-Enhanced Subcritical Fluid Extraction of Essential Oil from Nymphaea alba var and Its Antioxidant Activity

Background: The essential oil content of the water lily is extremely low; thus, finding a new method that can extract essential oil from water lilies with a high extraction rate and no residual organic solvents is essential. Objective: The optimal processing conditions for the ultrasound-enhanced subcritical fluid extraction of essential oil from Nymphaea alba var (red water lily) and the antioxidant activity of the essential oil in vitro are investigated to provide theoretical bases for identification and development. Methods: Single-factor experiments and orthogonal designs are performed to determine the effects of extraction conditions on essential oil yields. The chemical composition of essential oil is analyzed using GC–MS. Results: The optimum extraction parameters are established as follows: extraction temperature, 35°C; extraction time, 30 min/time for four times; ratio of material to liquid, 1:3; ultrasound power, 250 W/L; and ultrasonic frequency, 20 kHz. The extraction rate of essential oil is 0.315% under these conditions. Eleven components comprise more than 1% content. The main chemical constituents are 8-hexadecyne (31.04%) and 2,6,10-trimethyl-tetradecane (3.95%). The essential oil from N. alba var has an antioxidant activity in vitro; however, its antioxidant activity is weaker than that of butylated hydroxytoluene. Conclusions: Subcritical fluid is suitable for the extraction of essential oil from N. alba var, and the essential oil has a good antioxidant activity. Highlights: The essential oil content of N. alba var is 0.315%. Forty-seven chemical constituents are identified and isolated from N. alba var and analyzed by GC–MS.

Optimization On Subcritical Fluid Extraction Of Zingiberene

The establishment of subcritical fluid application for zingiberene extraction was studied by employing water as a green solvent. The zingiberene content was observed by using Liquid Chromatography-Mass Spectrofotometry and regarding to the independent variable of temperature, extraction time, ginger-solvent ratio and aging time. By applying subcritical water, the critical value of zingiberene content obtained was 0.036%. This value was approached by the surface modeling of alpha for rotatability design which performed at 125  C, 20 min of extraction time, 0.08 of ginger to solvent ratio and 9 min of aging time of extraction parameters. The surface modeling was validated by plotting the observed and predicted value of zingiberene content and evidenced by the value of R-square at 0.76.