This study investigated the effects of rice bran protein hydrolysate (RBPH) coupled with oxidized tea polyphenols (OTP) on the physical and oxidative stability of oil-in-water emulsions. Emulsions stabilized with RBPH alone were less stable than those stabilized with both RBPH and OTP. The OTP not only improved the emulsification stability, flocculation stability, coagulation stability, and ζ-potential of the emulsions, OTP also decreased the particle size, increased the adsorption capacity of the oil–water interface for RBPH, and effectively reduced the generation of peroxide and malondialdehyde in the emulsion during storage. The stability of the emulsion during the early stage of storage was maximized when the OTP content was 1.5%; at greater contents, the OTP competed with RBPH for adsorption at the interface, which affected the distribution of RBPH on the interface and decreased the emulsion stability. The results indicate that OTP can enhance emulsion stability, providing a reference for the application of oxidized polyphenols in food emulsions.

In this study, the occurrence, serogroups, virulence genes, antibiotic susceptibility profiles, and diversity were estimated for Listeria monocytogenes isolated from Pangasius fish in two processing facilities in Vietnam. L. monocytogenes was most frequently detected in wash water samples at 20.8 % (15 out of 72), and in Pangasius fish it was 16.6 % (15 out of 90 fish samples). Serotypes 1/2b were dominant, and internalin genes (inlA, inlC, and inlJ) were found in all the L. monocytogenes isolates. Most of the isolates were resistant to cefoxitin, oxacillin, and fosfomycin. Genotyping of L. monocytogenes by random amplified polymorphic DNA analysis revealed three clusters of the isolates specific to the facilities to some extent. This study suggests a high risk of L. monocytogenes contamination from wash water to fish. Hence, maintaining the quality of water and designing sanitation procedures to reduce L. monocytogenes contamination are required to ensure food safety at Pangasius fish processing plants.

In this study, we evaluated the microbial safety of Pangasius fish at two companies along the Vietnamese Mekong Delta. A microbial assessment scheme was used to diagnose the actual microbiological performance of implemented food safety management systems. The results showed that the microbial safety level profiles were the same at levels 1–2, indicating a poor-to-moderate food safety output of these companies. Microbial quality parameters including total mesophilic counts, Escherichia coli and coliforms, Staphylococcus aureus, and pathogens Listeria monocytogenes and Vibrio cholerae were not in accordance with the microbiological reference standards. Even though the quality of the raw Pangasius fish originating from the two companies was dissimilar as influenced by microbial ecology, the similarity in the microbial safety profiles of the two companies revealed the necessity of validating the efficiency of food safety management systems to improve the safety of the fish product.

Hyaluronan (HA) possesses radical scavenging properties. The low molecular weight HA (LHA)-containing drink (PL) is a dietary supplement that consists of several antioxidants in addition to LHA. The aim of this study is to characterize the hydroxyl radical scavenging activity of LHA through the interactions between the components of PL in in vitro assays. Moreover, the efficacy of LHA toward oxidative stresses (ultraviolet C irradiation, oxidative DNA damage) was evaluated. LHA revealed the following hydroxyl radical-scavenging properties: 1) LHA directly scavenges hydroxyl radicals, 2) LHA activity is enhanced in the presence of other PL components, thereby enabling protection against oxidative damage to DNA, and 3) exposure to UVC-radiation temporarily attenuated the antioxidant activity of PL, which is recovered in an LHA-dependent process. These results suggest that LHA is an excellent material because its antioxidative activity is enhanced in the presence of other antioxidants, which ultimately increases resistance to oxidative stress.

This study aimed to identify factors required for making high-quality rice flour and bread; six cultivars with various kernel appearances and amylose content from 10 % to 28 % were used. Flour samples with small particle sizes and low damaged-starch content were obtained from rice cultivars with high proportions of opaque-kernel grains, probably due to low hardness. Rice cultivars with high amylose content produced bread with high specific loaf volume (> 5.5). The specific loaf volume of gluten- and additive-free rice bread was significantly correlated with amylose content and moderately correlated with opaque-kernel grain proportion. Protein content was not significantly correlated with rice flour and bread properties. Thus, rice cultivars with high amylose content and high proportions of opaque-kernel grains would be suitable for making high-quality rice flour and bread.

The present study aimed to clarify the potential of edible films prepared from North Pacific krill (Euphausia pacifica) protein and the effects of various salt types (sodium chloride, sodium acetate, sodium benzoate, sodium citrate, and sodium tartrate) as solubilizers on the film properties. A film containing sodium chloride was used as a control. The physical properties and protein composition of films were determined. Results showed that all types of organic salts could be used to produce films with North Pacific krill protein. All film types were observed to have excellent ultraviolet barrier properties. The film containing sodium citrate had the highest mechanical properties and protein solubility, and the lowest absorbance of ultraviolet-visible light, indicating that sodium citrate is the most useful salt type assessed in this study. Thus, North Pacific krill represents a potential resource in the production of edible films for active food packaging.

Pyrrolizidine alkaloids (PAs) in 200 honeys and 63 bee pollens distributed in South Korea were investigated to evaluate their concentration and safety by simultaneous LC-MS/MS analysis. The risk of PAs’ intake was also evaluated. The average PA concentration in honey and bee pollen was lower in products produced in South Korea (honey, 4.2 μg/kg; bee pollen, 306.4 μg/kg) than in ones produced outside South Korea (honey, 24.3 μg/kg; bee pollen, 327.5 μg/kg). PA concentration in bee pollen was about 30 times higher than in honey. It was thought that bee pollen had a significant effect on PA concentration in honey, as honey and bee pollen showed similar PA detection tendencies. The daily exposure to PAs from honey intake was 0.0003 μg/kg body weight (b.w.) per day for all ages, and the safe margin of exposure (MOE) calculated based on BMDL10 237 μg/kg b.w./day was 722 759, which was a safe level (MOE 10 000 or more).

Salted radish root (takuan-zuke) turns yellow naturally; however, light-induced color fading reduces its commercial value. In this study, we evaluated strategies to protect the color of salted radish root and prevent fading in response to light, by evaluating the effects of various fluorescent lamps and light-emitting diodes (LED). Higher irradiance LEDs promoted the pale coloration of takuan-zuke; however, blocking shorter wavelengths, particularly those below 490 nm, suppressed color fading. The b^* value calculated from reflectance was significantly reduced by white or blue LEDs. Therefore, LED irradiation could enable easy and efficient achievement of pale coloration of salted radish roots. This study provides a theoretical basis for the development of a new method for the production of takuan-zuke without the use of food colorants.

The scuttle fly, Megaselia scalaris (Loew, 1866) (Diptera: Phoridae), is an insect of the family Dermatidae that often poses problems as a foreign substance contaminating foods. In this study, we developed a rapid identification method for this contaminant using mitochondrial DNA based on a molecular biology technique. From the entire region of mitochondrial DNA information, a region suitable for real-time polymerase chain reaction (PCR) was chosen, and two primers and a probe specific to M. scalaris were designed. A specificity test was performed with 17 species of pests that could be contaminants in food, and the developed real-time PCR method was confirmed to show a positive result only for M. scalaris. In addition, the limit of detection of this analysis method using a 10-µL PCR solution was 1 pg of total DNA, which revealed that the method was highly sensitive.

Lemon-flavored olive oil is one of several popular flavored oils on the market. This study aimed to examine the amount of limonene, an abundant aroma compound in lemon, that is transferred from lemon to olive oil under different flavoring conditions. First, the presence of limonene in different parts of fresh lemon tissue (flavedo, albedo, and tissues other than flavedo and albedo) was examined in olive oils flavored with each tissue. Limonene was found to be mainly distributed in the flavedo. Effects of extraction time, temperature, and quantity of the flavedo added were determined as independent variables. Results indicated that the extraction time and temperature influenced the amount of limonene transferred. In particular, the addition of increasing quantities of flavedo resulted in significant increases in the amounts of limonene transferred without increasing the oxidative degradation of the oil samples. We determined the optimal conditions for lemon-flavored olive oil preparation based on the amounts of limonene transferred.