The physical properties of foods related to mastication and swallowing are explained. The maximum velocity, V_max, obtained by the ultrasonic pulse Doppler method, and the time required for the bolus to flow in the pharynx, t₂>, obtained by acoustic swallowing sound, are considered to be good predictors of aspiration risk. For thickener solutions, the viscosity, µ, especially that measured at a shear rate of 20–30 s⁻¹ and above, can be a suitable index for liquid-type care foods for people with difficulties in swallowing. The ‘hardness’ is considered to be the most suitable index for semi-solid care foods among the parameters obtained by texture profile analysis (TPA). The V_max and t₂> can be interpreted as “cohesiveness (i.e., ease to form bolus)” of food from the viewpoint of the flow velocity distribution in the pharynx. On the other hand, ‘cohesiveness’ obtained by TPA does not reflect the ease of forming a bolus of food.

The objective of this study was to develop precise and rapid detection methods for Listeria monocytogenes in mushrooms when using real-time PCR. L. monocytogenes were enriched through the optimization of the enrichment broth. To determine the optimal supplement for bacterial growth, the various components were investigated. As a result, LEB with 2×ferric citrate (LEB+2FC) was shown the most effective on promoting the L. monocytogenes growth in mushrooms. L. monocytogenes was inoculated in King Oyster mushroom and Golden needle mushroom, and the samples were enriched. Consequently, L. monocytogenes in King Oyster mushroom was detected by 100% (8/8) using real-time PCR when enriched in LEB+2FC for 9 h. In Golden needle mushroom, the pathogen was detected (100%; 8/8) when enriched in LEB+2FC for 3 h. These results indicate that L. monocytogenes can be detected quickly to prevent Listeria-related foodborne illness from the consumption of mushrooms with enrichment using LEB+2FC and real-time PCR analysis.

Heating is conventionally used for preserving and extending the shelf-life of food products. However, the original taste, flavor, and texture of products can be changed with extended heating. In this study, we applied radio-frequency heating (RF), a technique that produces uniform heating and reduces the heating time, to extend the shelf-life of fresh-cut loquat fruit, also called biwa in Japan. Results demonstrated that the application of RF at 70, 80, and 90 °C maintained the color and textural quality of fruit samples as well as reduced the enzyme activity of polyphenol oxidase, which causes oxidative discoloration, during 21-day refrigerated storage. RF also reduced the heating time by up to five-fold as compared to conventional heating, leading to improved physical, chemical, and aroma attributes of the fresh-cut loquat fruit samples. In addition, RF also reduced the growth of Escherichia coli in the fresh-cut fruit, indicating that RF is a promising technology for extending the shelf-life of fresh-cut fruits and their products without compromising quality and safety.

This study aimed to create simplified models to rapidly and non-destructively predict the content of adulterated meat in restructured steak based on hyperspectral technology. The hyperspectral data for restructured steaks mixed with different proportions of pork and duck were collected, and then six pre-treatment methods were used to pre-process the spectral data. Importantly, the wavelength selection algorithm cascade strategy, that is, combined the wavelength range selection and wavelength band selection methods including successive projections algorithm (SPA), competitive adaptive reweighted sampling (CARS), variables combination population analysis (VCPA), interval random frog (iRF), iRF-SPA, iRF-CARS, and iRF-VCPA, were employed to establish a partial least squares (PLS) prediction model for adulterated content. The results showed that the best pre-treatment methods for beef adulterated with pork and duck were Mean centering (MC) and Savitzky-Golay (SG) respectively, and the corresponding best wavelength selection method was iRF-CARS.

The coproduction of glucan and mannan from yeast extract residue was examined by clarifying the material balance and energy consumption at the factory scale. As final products, yeast glucan and yeast mannan with purities of 46.2% and 50.9% were obtained at 92.6% and 65.9% yields, respectively. This result demonstrated that glucan and mannan can be produced simultaneously using the existing equipment at the yeast extract factory. Losses of glucan and mannan were mainly generated in the separation process at 5.4% and 29.1%, respectively. The energy in the total process per ton of raw material (yeast extract residue) containing 85.0% water by weight required 122 kWh of electricity, 1.54 t of steam (0.68 MPa, 174.5 °C), and 11.0 kg of liquid natural gas. The material balance revealed a quantitative relationship between purity and yield in the coproduction that will help optimize yeast-derived glucan and mannan production in the future.

The glass transition temperature (T_g) is an important physical property affecting the release of 1-methylcyclopropene (1-MCP) from its inclusion complex with α-cyclodextrin (α-CD). The release of 1-MCP from α-CD was investigated using humidity ramping at constant temperature and temperature ramping at constant humidity. The apparent T_g values of α-CD were estimated from the collapse temperatures observed in the release experiments and compared with the temperatures calculated using the Gordon–Taylor equation. Good agreement between the estimated and calculated T_g values indicated that the ramping method for flavor release from a powder matrix would be a simple and effective approach to estimate the T_g of the matrix.

‘Beihong’ is a new eurasian vinifera hybrid cultivar and widely planted in many wine regions and selected for wine making in China. However, studies on the fungal diversity of this cultivar was scarce. In this study, the indigenous yeast diversity and theirs dynamic changes during the spontaneous fermentation of ‘Beihong’ from Guiyang region, Guizhou, China, was analyzed and monitored using high-throughput sequencing and culture-dependent approaches. The result demonstrated that the composition of yeast species revealed by the two methods was quite different. In addition, non-Saccharomyces yeasts were predominant in the initial stages of fermentation and then rapidly decreased, while Saccharomyces yeast sharply increased during the process. Hanseniaspora sp. and Saccharomyces cerevisiae were the main yeast isolates at the third day of fermentation. Taken together, the present study was a first step in exploring untapped yeast resources of ‘Beihong’ from Guiyang region, showing the basic information on indigenous yeast diversity, which was helpful to screen these native yeasts for producing wines with regional characteristics.

Glucosinolates in cruciferous plants have been reported to exhibit various health benefits. Consequently, several studies have focused on the quantification of glucosinolates. A simple method was developed in this study to quantify glucosinolates in nozawana (Brassica rapa L.), and the validity of the developed method was evaluated. Glucosinolates were extracted from a dry powder of nozawana, solid-phase extraction was performed, and liquid chromatography–mass spectrometry measurements were conducted. A single-laboratory validation study on the developed method suggested that the relative repeatability standard deviation, relative intermediate standard deviation, and recovery rate of the spike and recovery tests complied with the accuracy standards of the Association of Official Analytical Chemists (AOAC) guidelines. Additionally, a multi-laboratory (three laboratories) validation study revealed that although the Horwitz ratio (HorRat) for trace glucosinolates was over 2, that for the primary glucosinolates in nozawana was less than 2, indicating an appreciable degree of reproducibility.

To identify the components in Hyuganatsu orange (Citrus tamurana Hort. ex Tanaka) that improve bone metabolism function, the structure of the polysaccharide PWH fractionated from water extracted from Hyuganatsu orange juice was investigated. The findings showed that PWH consisted of arabinogalactan with a molecular mass of 68 kDa. Monosaccharide compositional analysis indicated that PWH contained galactose, arabinose, and rhamnose at a ratio of 57:27:16. Using the methods of methylation analysis, partial acid hydrolysis, and NMR, PWH was indicated to be a type II arabinogalactan with a backbone of 1,3-linked galactopyranosyl residues. Furthermore, it was found that PWH effectively inhibited the fusion of osteoclasts. The results showed that the functional component of Hyuganatsu orange that inhibits osteoclast formation contains PWH.

Though salmon protamine (PRO) is known to exhibit strong antibacterial action, the effect of PRO on the physicochemical properties of porcine myofibril (Mf) are not yet fully understood. In this study, we investigated the effect of PRO on the rheological properties of Mf proteins. The viscosity of the Mf homogenate decreased with increasing PRO in a concentration-dependent manner. The breaking stress of the thermal gel was reduced in the presence of PRO. Scanning electron microscopy examination showed that PRO had a 3-dimensional network structure with thread-like protein filaments. SDS-PAGE analysis demonstrated that myosin binding protein-C and myosin light chain 1 in Mf were solubilized by the addition of PRO. However, PRO inhibited the solubilization of α-actinin. These results showed that PRO had an adverse effect on the gelling properties of porcine Mf through the protein-protein interaction between PRO and Mf proteins.

Dry-heat-treated sodium caseinate improves yogurt curd strength, but its production is time-consuming. Thus, a simpler pretreatment is needed. We conducted this study to investigate the effects of dry-heat treatment (65 °C, RH 8 %, 2–6 days) of skim milk powder on acid-induced gelation and identify improvement factors. Acid-induced gels were formed by the addition of 1.84 % (w/v) glucono-δ-lactone to skim milk powder dispersions (protein conc., 40 mg/mL). Gel strength improved proportionally to dry-heat treatment duration. We examined the relationship between the improvement of curd strength and protein denaturation induced upon heat treatment of skim milk powder. We observed improved curd strength due to a decrease in zeta potential and an increase in the surface hydrophobicity of casein micelles as well as cross-linking of caseins, which were a result of Maillard reactions. These results suggest that dry-heat treatment of skim milk powder is useful for yogurt manufacturing.

Microwave heating results in the generation of odorous compounds in sliced sponge gourd (Luffa cylindrica). Herein, the odorous components of microwave-heated sponge gourd were extracted, and the volatiles were separated by a solvent-assisted flavor evaporation technique. Subsequently, gas chromatography (GC)–olfactometry analysis identified 10 compounds in the aroma extract including unsaturated aliphatic aldehydes (3-hexenal; 2-octenal), alcohols (3-hexen-1-ol; 1-octen-3-ol), and ketones (1-octen-3-one; 1,5-octadien-3-one), which might be responsible for the typical green-grassy and metallic characteristics. Microwave heating could also promote the nonenzymatic browning reaction in the softened gourd to release methional and 2-acetyl-1-pyrroline, which have boiled potato and roasted-peanut odors, respectively. Furthermore, preparative GC–mass spectrometry was used to distinguish two methoxypyrazines (3,5-dimethyl-2-methoxypyrazine and 3-isopropyl-2-methoxypyrazine) responsible for a highly noticeable, unpleasant musty-peanut aroma in heated sponge gourd. Moreover, 3-isopropyl-2-methoxypyrazine might also generate an unlikeable earthy odor, resulting an off-flavor, and thus could be used as one of quality markers in sponge gourd.