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We treated dry black bean dreg fermentation products with radio-frequency (RF) waves. With RF treatment (RF output power of 3 kW and electrode gap of 12 cm), a sample was dried within 1 h, which would take 10 h to dry via hot-air drying at 60 °C (sample weight reduction from 100 to 28.2 g). RF treatment thus accelerated fermented black bean dreg drying approximately 10-fold. The fermented black bean dregs were dried for 60 min at a fixed RF output power of 3 kW with different electrode gaps (12, 16, and 20 cm). Samples treated with electrode gaps of 12 and 16 cm were completely dried. When the fermented black bean dregs were dried for 60 min with an RF output power of 3 kW with a 16 cm electrode gap, their water activity decreased from 0.98 to 0.65. Colorimetric analysis showed that the sample color darkened significantly (ΔE = 5.73 ± 2.71), whereas its solubility (28.8 ± 0.1%) and antioxidant capacity (EC50 = 51.7 ± 0.7 mg/mL) increased. In addition, deglycosylated isoflavone daidzein content significantly increased, whereas that of the glycosylated isoflavone genistin decreased. These results reveal that RF application can efficiently dry fermented black bean dregs. [ABSTRACT FROM AUTHOR]

The effects of transglutaminase (TGase), reductant, and thermal treatment on the cross-linking of white proteins in soft-shell turtle eggs were investigated. Egg white proteins were denatured by reductant (0.83% 2-mercaptoethanol, 2-ME) pretreatment and thermal pretreatment (95 °C and 5 min), and the denatured proteins were then catalyzed by TGase (1.0 unit/mL). SDS–PAGE showed that without any pretreatments, three major egg white proteins (210 kDa, 115 kDa, and 76 kDa proteins) were inferior substrates for TGase. Only portions of the 210 kDa protein (7.9%), 115 kDa protein (11.4%), and 76 kDa protein (42.9%) were polymerized by TGase into high-molecular-weight (MW) protein polymers (>180 kDa) after incubation for 3 h at 40 °C. However, the combined use of TGase with 0.83% 2-ME and thermal pretreatment led to a significant increase (p < 0.05) in the rate of white protein polymerization after 3 h: 210 kDa protein (90.8%), 115 kDa protein (69.5%), and 76 kDa protein (72.2%). Particle size analysis indicated that these cross-linked high-MW protein polymers were 2000–10,000 nm in size. Based on the experimental results, egg white proteins denatured by 2-ME and heat pretreatment are more prone to TGase-induced cross-linking. [ABSTRACT FROM AUTHOR]

Soybean oil and palm olein were used to fry French fries, chicken leg fillets and pork chops. Total polar compounds were measured by column chromatography and two rapid-measuring devices (Ebro FOM 310 and Testo 270). Acid value was determined by titration method and a 3M Shortening Monitor. The results showed that the content of total polar compounds and acid value in both soybean oil and palm olein increased linearly with frying time. The influence of oil type on the content of total polar compounds and acid value in used oil was significant, but the effect of food type on these parameters was not observed. The rate of total polar compounds generation in palm olein was lower than that in soybean oil. All rapid methods used in this study had results that highly correlated with those from column chromatography, but moderately correlated with the titration method. We found that Ebro FOM 310 was more suitable for monitoring the quality of soybean oil during frying, while Testo 270 was suitable for palm olein. These results provided the basis for choosing the proper rapid-measuring device to control the quality of frying oil in restaurants. [ABSTRACT FROM AUTHOR]

Sixteen red rice accessions from the southern United States were studied for their physical, milling, pasting, and thermal properties, chemical composition, and starch fine structure relative to cultivated medium- and long-grain rice varieties. All red rice samples were medium-grain, but their physicochemical properties were different from those of Bengal, a cultivated medium-grain rice. Their apparent amylose and crude protein contents were generally higher, and their amylopectin structure consisted of a higher percentage of the shorter branch chains (DP6-24) and a lower percentage of the longer branch chains (DP25-65). Red rice starch pasting and thermal properties were similar to those of Wells, a long-grain rice cultivar. The red rice samples can be classified into two major clusters according to their kernel properties by hierarchical cluster analysis: one cluster with more resemblance to Wells and another cluster with more resemblance to Bengal. Starch structure and kernel physicochemical properties may offer an alternative way of classifying red rice in addition to phenotypic and genetic indices.

Lipase-catalyzed acetylation of cellulose solubilized in the dimethyl sulfoxide/paraformaldehyde organic solvent system was conducted with lipase A12 from Aspergillus niger. The accompanying side cellulase activity of the A. niger lipase partly accounted for the enhanced acetylation mediated by the enzyme, via facilitating the partial degradation of cellulose substrate as evidenced by high-performance size exclusion chromatograph analysis. The enzymatic cellulose acetylation was improved by substrate pretreatment with cellulase or ultrasound by 18 and 14%, respectively, as a result of the reduced substrate molecular size. Additionally, the ultrasound-pretreated cellulose as the starting substrate was beneficial for the cellulose solution preparation due to the increased accessible surface of cellulose as evidenced by its increased sedimentation volume and SEM micrographs. The effect of thermodynamic water activity (aw) on lipase catalytic activity in organic media was also investigated. The maximum acetylation extent (nearly 11 wt %) occurred at aw = 0.52, which was improved by 51% relative to the enzymatic reaction with no control of water activity. The much larger extent to which the lipase-catalyzed cellulose acetylation was enhanced by water activity optimization than by substrate pretreatment further supported the predominant role played by the major lipase activity of the A. niger lipase over its side cellulase activity in catalyzing cellulose ester synthesis in organic media.