Physicochemical properties of partially α-glucan-coated normal corn starch formed by amylosucrase from Neisseria polysaccharea.

Amylosucrase (AS) is a glycosyltransferase that produces linear α-1,4 glucans using sucrose as the sole substrate. In this study, for various applications, α-glucan-coated starch (α-GCS) was produced by AS (20 U/Lreactant) from Neisseria polysaccharea to improve the physicochemical properties of raw normal corn starch (NCS) by applying different reaction conditions (i.e., varying the substrate concentration, pH, and temperature). Field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) showed that raw NCS was successfully coated by α-glucan. Differential scanning calorimetry (DSC) and rapid viscosity analyses (RVA) of the α-GCS confirmed that the α-glucan coating decreased the degree of retrogradation. Notably, compared to raw NCS as a control, starch retrogradation was significantly (p < 0.05) decreased by 13.7% after five weeks. Therefore, the novel α-GCS can be applied as a functional material for controlled retrogradation in the starch-based food industry for shelf-life extension.

The influence of in vitro pectin fermentation on the human fecal microbiome.

Pectin is a complex dietary fiber and a prebiotic. To investigate pectin-induced changes in the gut microbiome and their effects on the short chain fatty acids (SCFAs) production, we performed in vitro pectin fermentation using the feces of three Korean donors. The pectin degradations in all three donors were observed. While the donors displayed differences in baseline gut microbiota composition, commonly increased bacteria after pectin fermentation included Lachnospira, Dorea, Clostridium, and Sutterella. Regarding SCFAs, acetate levels rapidly increased with incubation with pectin, and butyrate levels also increased after 6 h of incubation. The results suggest that pectin fermentation increases bacterial species belonging to Clostridium cluster XIV (Lachnospira, Dorea, and Clostridium), with Lachnospira displaying the greatest increase. The results also confirm that pectin fermentation leads to the production of acetate and butyrate.

Effects of millimeter wave treatment on the germination rate and antioxidant potentials and gamma-aminobutyric acid of the germinated brown rice.

Many studies have been conducted to promote germination in brown rice in order to improve its nutritional value in terms of enzymes, protein quality, and micronutrient content. The purpose of this study was to investigate the effect of millimeter wave on germination. Millimeter wave is a form of electromagnetic radiation with frequency between 30 and 300 GHz, and is also called 'biomicrowave'. Millimeter wave significantly stimulated germination. Total polyphenol content and DPPH radical scavenging activity also increased, especially at high frequency and prolonged dose. However, γ-aminobutyric acid content was diminished.

Effect of millimeter waves on the microbiological and physicochemical properties of Korean rice wine Makgeolli.

Millimeter waves are electric waves between 30 and 300 GHz. They are known to affect microbial growth. Here, the effects of millimeter waves on the microbiological and physicochemical properties of Makgeolli irradiated during fermentation were investigated. Millimeter waves at 60 and 70 GHz were used, and the fermentation was carried out at 30°C. The numbers of both lactic acid bacteria and yeasts have changed with similar pattern each then during the fermentation, but the effect of milimeter wave treatment was not critical as growth patterns were independent of both irradiation period and wave frequency. Furthermore, pH and total acidity did not change during fermentation. Although irradiation drastically increased sugar production during the initial stage of fermentation, the change was not frequency dependent. At the end of fermentation, the alcohol content in irradiated Makgeolli was definitely higher than that in un-irradiated Makgeolli, and the difference was frequency dependent.

Effects of Freeze-dried Mulberry on Antioxidant Activities and Fermented Characteristics of Yogurt during Refrigerated Storage.

This study investigated the effect of added freeze-dried mulberry fruit juice (FDMJ) (1, 3 and 5%) on the antioxidant activity and fermented characteristic of yogurt during refrigerated storage. A decrease in pH of yogurt and increase in acidity was observed during fermentation. The yogurts with FDMJ exhibited faster rate of pH reduction than control. Initial lactic acid bacteria count of yogurt was 6.49-6.94 Log CFU/g and increased above 9 Log CFU/g in control and 1% in FDMJ yogurt for 24 h. The total polyphenol and anthocyanin content of FDMJ yogurt was higher than that of control due to the presence of phytochemical contents in mulberry. Moreover, antioxidant activity such as DPPH and reducing power was highest 5% FDMJ yogurt. During cold storage, pH decreased or remained constant in all yogurts with values ranging from 4.08 to 4.78 units. In sensory evaluation, the score of 1% FDMJ yogurt was ranked higher when compared with other yogurts. It is proposed that mulberry fruit juice powder can be used to improve sensory evaluation and enhance functionality of yogurt.

Effects of Edible Seaweed on Physicochemical and Sensory Characteristics of Reduced-salt Frankfurters.

The effects of sea tangle, sea mustard, hijiki, and glasswort were investigated based on the proximate composition, salinity, cooking loss, emulsion stability, pH, color, texture profile analysis, apparent viscosity, and sensory characteristics of reduced-salt (NaCl) meat batter and frankfurters. The moisture content, salinity, lightness of the meat batter and frankfurter, hardness, gumminess, and chewiness of the reduced-salt frankfurters with sea weeds were lower than the control without seaweed (p<0.05). The protein content, springiness, and cohesiveness of the reduced-salt frankfurters were not significantly different among the treatments (p>0.05). The moisture content, salinity, cooking loss, lightness, redness, hardness, gumminess, and chewiness of treatments with sea tangle and with sea mustard were lower than the control (p<0.05). Among the sensory traits, color was highest in the control (p<0.05). The flavor was also highest in the control. The treatments with sea tangle and with sea mustard samples had high tenderness, juiciness, and overall acceptability scores similar to the control (p<0.05). The results of this study show that the combination of low-salt and seaweed in the formulation successfully improved reduced-salt frankfurters, improving sensory characteristics to levels similar to the regular salt control (1.5%).