Dianyu Yu

Green separation technologies in food processing: supercritical-CO2 fluid and subcritical water extraction

Application of separation technologies is done to recover high value components from agricultural commodities and is an important operation in food processing, especially for the development of health-promoting food ingredients. There is significant interest from the scientific community and increasing industrial demand to perform research and development on extraction and separation technologies, with the goal of eliminating the use of organic chemicals. This is primarily because these products are increasingly used in producing functional ingredients and natural products that must respect regulations for safety, health, and environmental impacts. In fact, one of the most important trends in the food industry today is the demand for “natural” foods and ingredients that are free from toxic-chemical additives. A number of newer separation techniques such as supercritical-CO2 fluid extraction technology and subcritical water extraction are possible alternative methods providing environmentally friendly “green” processing techniques for new or improved food processing applications. Many potential high-value products can be developed from natural resources using these “green” environmentally friendly separation technologies and processes. The use of “green” separation technologies and processes have the potential to provide phytochemicals from plant materials, while retaining or even improving their bioactivity and functionality, meeting food regulation guidelines, as well as ensuring that the separation is done effectively and economically. Utilization of natural agricultural materials for the production of high value-added products using “green” separation technologies and processes will likely continue to be of great interest to the food and biotechnology industries.

Thermal and crystal characteristics of enzymatically interesterified fats of fatty acid-balanced oil and fully hydrogenated soybean oil in supercritical CO2 system

ABSTRACT Blends of fatty acid-balanced oil that was prepared by the aqueous enzymatic extraction, and with fully hydrogenated soybean oil in different weight ratios from 30:70 to 80:20 (wt%) were interesterified using Lipozyme RM IM in a supercritical CO2 system. The optimal immobilized enzyme dosage, pressure, substrate ratio, temperature, and time were 6% (w/w) of initial substrates, 8 MPa, blend ratio with 60:40 (wt%) of fatty acid-balanced oil and fully hydrogenated soybean oil, a temperature of 70°C, and reaction time of 2 h, respectively. It was observed that at the optimal conditions, under supercritical CO2 conditions, the reaction time of the interesterification was shorter than that of conventional enzymatic interesterification. The slip melting point, solid fat content, fatty acid composition, differential scanning calorimetry, polymorphic form and crystal morphology of the enzymatically interesterified fats were evaluated. The results indicated that the interesterified fats showed desirable physical properties with lower slip melting point and solid fat content, suitable crystal form (β′ polymorph), and without trans-fatty acid for possible use as a shortening and margarine stock.

Preparation of the Pt/CNTs Catalyst and Its Application to the Fabrication of Hydrogenated Soybean Oil Containing a Low Content of Trans Fatty Acids Using the Solid Polymer Electrolyte Reactor

Pt/CNTs were synthesized with an ethylene glycol reduction method, and the effects of carboxyl functionalization, ultrasonic power and the concentration of chloroplatinic acid on the catalytic activity of Pt/CNTs were investigated. The optimal performance of the Pt/CNTs catalyst was obtained when the ultrasonic power was 300 W and the concentration of chloroplatinic acid was 40 mg/mL. The durability and stability of the Pt/CNTs catalyst were considerably better compared to Pt/C, as shown by cyclic voltammetry measurement results. The trans fatty acids content of the obtained hydrogenated soybean oil (IV: 108.4 gl2/100 g oil) using Pt/CNTs as the cathode catalyst in a solid polymer electrolyte reactor was only 1.49%. The IV of hydrogenated soybean oil obtained using CNTs as carrier with Pt loading 0.1 mg/cm2 (IV: 108.4 gl2/100 g oil) was lower than carbon with a Pt loading of 0.8 mg/cm2 (IV: 109.9 gl2/100 g oil). Thus, to achive the same IV, the usage of Pt was much less when carbon nanotubes were selected as catalyst carrier compared to traditional carbon carrier. The changes of fatty acid components and the hydrogenated selectivity of octadecenoic acid were also discussed.