Supercritical fluids have been applied for food related material processing including decaffeination of coffee and hop extraction for beer production. Fundamental properties of sub- and supercritical fluids are briefly explained in this article. Solubility of solutes in supercritical fluids is the most important property in separation process. Extraction process using supercritical carbon dioxide from solid feed material is reviewed. Fractionation of liquid mixture is also important area for food industry such as separation of lipids and essential oils. Recently, subcritical water is applied for extraction process for natural materials. Hybrid extraction process of supercritical carbon dioxide and liquid water was proposed for simultaneous extraction of polar and nonpolar components and successfully applied food related materials. Supercritical carbon dioxide has been applied for fine particle production of natural materials such as carotenoids. In situ micronization of subcritical water extracts was also explained.
Low-moisture food products commonly show glass to rubber transition (glass transition) at the glass transition temperature (Tg), and their physical properties are changed drastically. Since the Tg of hydrophilic materials decreases with increasing water content because of water plasticizing effect. Consequently, it is of practical importance to understand effect of water content on the Tg of food products. In this article, glass transition properties and quality control of food products are explained. Effects of water and maltodextrin on the Tg of freeze-dried mango puree were investigated systematically using differential scanning calorimetry (DSC). The Tg of mango puree increased with an decrease in water content and an increase in maltodextrin content. This result will be useful for the physical stability control (e.g., collapse, caking, and sugar crystallization) of freeze-dried mango puree. Although cookie sample showed indistinct glass transition behavior in DSC thermosgram, thermal rheological analysis revealed a clear glass transition, and thus mechanical Tg of cookie sample was evaluated. The mechanical Tg of cookie increased and decreased by the addition of trehalose and sorbitol, respectively. This result will be useful for the texture control of cookie.
The dehydration of biopharmaceutical products through drying provides numerous benefits, including ease of handling and storage, reduction in transportation costs, and improved stability. Typically, the drying of biotherapeutics is accomplished through freeze-drying, however, the removal of water by lyophilization possesses several drawbacks, including lengthy drying times, low energy efficiency, and the high cost of purchasing and maintaining the equipment. Furthermore, freeze-drying is a batch process which may be challenging to adapt and implement with the recent push for continuous manufacturing. These limitations have led to the search for next-generation drying technologies that can be applied to the manufacture of biotherapeutic products. Several alternative drying methods to freeze-drying have been developed and implemented in industries outside of pharmaceuticals, such as food and agriculture, and some are at an advanced state. With the aim of applying lessons learned from technologies in various industries, herein, we review several processing technologies with particular emphasis on the advantages and disadvantages of each in comparison to lyophilization and their potential to be adapted and utilized for drying biotherapeutic compounds.
This study investigated the effect of hydrothermal pre-treatment on ferulic acid content and antioxidant activities of corn hydrolysate. The low-grade corn was treated by hot water and autoclaving process at different temperatures and times. The highest phenolic content (471.7±7.4μg FA.mL-1, p＜0.05) was obtained by autoclaving at 121℃ for 90 min. High performance liquid chromatography (HPLC) revealed 277.3±3.2μg.mL-1 of FA, which was 2.05 times higher than that of the control (unheated sample). The high yield of FA obtained here may be due to high-temperature autoclaving eliminating the FA-lignin and FA-polysaccharide bonds. Furthermore, the optimal hydrothermal pre-treatment at 121℃ for 90 min improved the DPPH and ABTS radical scavenging activities by 1.3 and 1.5 fold, respectively, compared to the control. On the other hand, the dextrose equivalent (DE) values obtained from corn hydrolysate at the different heat treatments in this study were in the range of 23.2±0.7 to 28.7±0.9. These results illustrated that autoclaving method showed a promising pre-treatment process to add value of corn hydrolysate product.
A method for calculating the productivity of simulated moving bed (SMB) chromatography based on the optimized repeated cyclic operation (RCO) chromatography was proposed. As a model system, a two-component separation system was chosen, where the distribution coefficients were controlled by changing the mobile phase composition. First, the sample feed volume per bed volume and the mobile phase velocity for the optimized RCO were used for determining the two inlet and the two outlet flow rates and the two zone velocities. The same HETP vs. flow velocity equations were used both for RCO and SMB. By using the parameters determined numerical calculations were carried out for the two different differences in the distribution coefficients. When the difference in the distribution coefficients was large, the productivity value of RCO was higher than that of SMB. The productivity of SMB was slightly higher for a smaller difference in the distribution coefficients.
To utilize blue shark Prionace glauca which is under-used resource, the effect of sodium alginate and calcium chloride on the gel property of the fish meat gel was investigated for improving its low gel-forming ability. Breaking stress of the fish meat gels was enhanced by adding more than 3％ sodium alginate and then immersing 1％ calcium chloride (aq). On the other hand, breaking deformation of the gels was decreased by the addition of sodium alginate and their physical properties were similar to those of abalone. SDS-PAGE patterns showed that protein polymerization in the gels depended on the concentration of sodium alginate. These results indicated that a new gel product having unique textures like abalone can be developed using blue shark meat with sodium alginate and calcium chloride.
The aim of this study was to investigate the effects of salt on the kinetic parameters of thermal protein denaturation of egg constituents. Egg whites and yolks containing different quantities of added salt were analyzed using differential scanning calorimetry (DSC) and dynamic viscoelastic oscillatory measurements. DSC measurements revealed an increase in the denaturation temperatures of the second peaks of egg whites and yolks in the presence of elevated salt concentrations. Given that the activation energy values obtained from the kinetic analysis of egg proteins using dynamic DSC were comparable, we suggest that salt affects not the denaturation rate of the egg protein, but the temperature of denaturation. Dynamic viscoelastic oscillatory measurements revealed that the gel-point temperatures increased with increasing salt concentrations. The elevated gel-point temperatures coincided with the temperature of the maximum denaturation rate calculated using the kinetic parameters.