The protein drugs should remain stable for several years even under unfavorable conditions during transport or storage. There are several methods for the production of the protein drugs, including freeze drying and spray drying. Spray drying is a method with a high potential and attractive alternative in preparation of solid pharmaceutical drugs by freeze drying. Spray drying is often regarded as a ‘harsh’ drying method due to the surface induced denaturation of bio-molecules during processing, since atomization and subsequent drying could potentially be detrimental to heat sensitive biological materials such as enzyme. Therefore, it is important to develop new formulation concept for encapsulation and stabilization of proteins during spray drying. This article reviewed several factors which result in the substantial inactivation of enzyme protein during spray drying, including the operational conditions of spray drying, the formulation of the feed enzyme solution and additives.
Antioxidant activities of 14 commercially available herb teas have been evaluated. Scavenging effects against hypochlorite ion and hydroxyl radical were determined with a method previously proposed by the authors, and expressed as myoglobin protective ratio. The antioxidant activities of the samples were also measured by the widely used DPPH method. In order to characterize the properties of the samples comprehensively, the antioxidant activities against three different radicals were compared in a radar chart. The patterns of the radar charts were similar to that to polyphenols, and the strength of the activity was rated as three ranks. Rose red, peppermint, lemon balm showed strong activity, and chamomile, linden, rosemary, hibiscus, rose hip, and raspberry leaf showed mild antioxidant activity. On the other hand, lemon grass, thyme, lavender, jasmine and erica did not show activity. Although the antioxidant activity of herb tea is strongly depend on the various factors such as origin, preparation methods, their characteristics can be successfully evaluated by the proposed radar chart in quantitative way.
Fine grinding technology is expected to permit various application of rice flour, however, it will decrease flowability of rice flour, resulting in formation of bridge and cohesion of powder inside the food processing machine. To determine necessary equipments and technologies for the processing of fine rice flour, this study investigated Carr’s flowability and floodability indices, moisture content, and roughness coefficient of the flours made from nonglutinous rice (white/brown) and glutinous rice (white), having the mean diameters of 3～30μm and 30～100μm milled by a jet mill and a hammer mill respectively. Although the moisture content and the roughness coefficient decreased as the mean diameter of the rice flour decreased, its flowability decreased as the mean diameter decreased down to 15μm. In the flours at 3μm mean diameter, the flowability of white rice flour was almost same with that of 15μm flour, while it increased in the brown rice flour. The rice flours with the mean diameter less than 30μm were less flowable than traditional rice flour joshinko, however as flowable as ordinary wheat flour.
Defatted rice bran treated using subcritical water at temperatures between 150 and 180℃ for 10 min was further treated under subcritical condition at 250℃ for 5 min. The bran extracts obtained from the first-step treatment were evaluated on their emulsifying and emulsion-stabilizing activities by the Pearce and Kinsella method and spectrophotometry at 500 nm. The emulsifying activity of the bran extracts was not dependent upon the first-step treatment temperature. The bran extracts performed equally well in stabilizing emulsions through the test storage period. The antioxidative ability of the bran extracts from each series of the two-step subcritical water treatment was assessed by measuring the induction period and also by monitoring the pressure drop in the closed bottle where oxidation took place. The oxidation was better suppressed in samples added with greater amount of bran extracts. The suppression of coloration of bran extracts by two-step treatment was studied. The bran extracts from the first-step treatment showed high emulsion-stabilizing activity, while the subsequent treatment yielded extracts with a radical scavenging activity comparable to that of the control bran extract obtained from a single-step treatment at 250℃. The two-step subcritical water treatment of defatted rice bran produced higher overall yields compared to the single-step treatment, but showed no noticeable influence upon suppression of coloration in the bran extracts.
The amphilic antioxidant, such as acyl ascorbate, would be expected to be a useful food additive. In this study, the antioxidative action of acyl ascorbate was examined, because knowledge of its behavior in aqueous solution is required for its effective use for food. First, the degradation kinetics of (+)-catechin in aqueous solution at various pHs and temperatures were empirically expressed by the Weibull equation. The rate constant, k, was the lower at the lower pH and temperature. The temperature-dependency of the k value was analyzed on the basis of the Arrhenius equation, and it was indicated that the enthalpy-entropy compensation held during the degradation. Second, octanoyl l-ascorbate was synthesized by the condensation of l-ascorbic and octanoic acids in acetone using immobilized lipase from Candida antarctica, and the degradation kinetics of catechin in aqueous solution in the presence of octanoyl ascorbate was examined. The dependency of the k value in the catechin solution with octanoyl ascorbate on the concentration of the ascorbate was obviously different from that with ascorbic acid. That is, the degradation was suppressed at low octanoyl ascorbate concentrations, while proceeded fast at a high concentration, suggesting the formation of the micelle for octanoyl ascorbate at high concentrations.
Vacuum Spray Drying (VSD) produces powders at lower temperature (40-60℃) due to vacuuming of the drying chamber to low atmospheric pressures (10-20 kPa). In this study the spraying and drying characteristics in the vacuumed drying chamber was investigated experimentally to have fundamental data on the design and operation of VSD. Condensed milk and yogurt slurry as feeding materials were sprayed in the vacuumed or non-vacuumed drying chamber and the sprayed droplet diameters were determined. Analysis of the relationships between droplet diameter and volumetric flow rate of spray air or spray pressure revealed that the droplets sprayed into the vacuumed chamber became smaller and these fine droplets were produced even at lower flow rate of spray air. However the drying in VSD was insufficient when the spray was conducted at the lower flow rate of spray air. On the contrary higher flow rate resulted in the discharge of fine powders out of the drying chamber so that some methods to collect those fine powders easily should be devised to improve the drying performance of VSD.