Streptococcus thermophilus is a lactic acid bacterium used along with Lactobacillus delbrueckii subsp. bulgaricus as a starter culture for yogurt production. Thus, there are many reports on the isolation and characterization of S. thermophilus from dairy products. On the other hand, literature on the isolation of S. thermophilus from plants is limited. Here, we investigate the isolation of S. thermophilus from 688 samples of twigs, leaves, stems, flowers, and berries collected from healthy trees (66 species) and grasses (40 species) found in Japan. Eight S. thermophilus strains were obtained from Acer palmatum var. matsumurae, Cornus controversa, C. officinalis, Fagus crenata, Lagerstroemia indica, Magnolia denudata, and Quercus crispula var. crispula. Then, we evaluated the characteristics of milk fermentation by using these eight strains. All eight strains fermented milk, and six of them coagulated 10% (w/v) skim milk within 6 h at 40 °C. Finally, we characterized susceptibility to syneresis by centrifugation. Milk fermented by the plant strains was more resistant to syneresis than milk fermented by three S. thermophilus strains isolated from commercial yogurts. We found that S. thermophilus can be isolated from some plants found in Japan, and these plants are useful sources of S. thermophilus for milk fermentation.

Lipase based enzymatic TTI was prepared using tricaprylin as substrate to monitor thermal abuse history of frozen chicken meat during supply chain. TTI showed an irreversible distinct colour change from initial green to intermediate orange to final red during temperature abuse with corresponding decrease in pH of TTI solution from 8.11 to 6.93 and 5.75, respectively. Temperature dynamicity of TTI on kinetic parameters was derived through Arrhenius equation and activation energy (Ea) of TTI was calculated as 50.94 kJ/mol. At different temperature abuse conditions viz. 5 ± 1 °C, 15 ± 1 °C, 25 ± 1 °C, and 35 ± 1 °C, quantitative changes in various parameters of chicken meat were evaluated and correlated with distinct colour response of TTI. The results showed significant correlation of parameters with colour changes in TTI at 35 ± 1 °C, insignificant correlation at 5 ± 1 °C and 15 ± 1 °C and slight correlation at 25 ± 1 °C indicating concurrent change in quality characteristics of frozen chicken meat on exposure to different temperature abuse conditions. Therefore, suggesting single lipase based enzymatic TTI cannot be utilized for quality marking of frozen chicken meat at different temperature abuse conditions.

Steviol glycosides are found in the leaves of Stevia rebaudiana Bertoni plants and have been used as natural, high-intensity sweeteners. Rebaudioside D (RebD) is a steviol glycoside derivative that has a similar sweetening profile to that of sugar; however, it is poorly soluble in water. Therefore, in this study, polymorphs of RebD showing greater solubility were investigated. We identified at least two novel polymorphs using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). We identified the transition to one polymorphic form of RebD (named “form α”) by desolvation at about 50 °C, and the other (named “form β”) at about 70 °C. Both forms exhibited greater water solubility compared to untreated RebD. This is the first report of RebD polymorphs with improved solubility, which may contribute to the production of RebD with both a sugar-like taste profile and high-solubility property.

Spiced beef is a representative traditional Chinese processed beef product. In order to establish quality evaluation of aroma profile, the widely accepted and characteristic volatile flavor of seven typical spiced beef was investigated using headspace solid-phase microextraction combined with gas chromatography-olfactometry-mass spectrometry. A total of 67 volatile flavor compounds were identified in the spiced beef, with 23 compounds in common and 30 aroma-active compounds. The common key aroma-active compounds of the seven types of spiced beef included p-allyl-anisole, 1-methoxy-4-(1-propenyl)-benzene, 3-methyl- 1-butanol, linalool, chavicol, α-phellandrene, myristicin, (Z)-3-hexenol, 1-terpinen-4-ol, furfuryl alcohol, dimethyl pyrazine, and 3-mercaptothiophene. The seven types of spiced beef could be divided into three categories based on their characteristic odors. These three categories had rich odors of sulfur-containing compounds, aldehydes, and spice, respectively. The characteristic odor reflects the geographical differences in consumption habits in China.The results provided a theoretical reference for quality evaluation of packaged spiced beef aroma profile.

The technological conditions for preparing sweet potato resistant starch (RS) by utilising the synergy of dry heating with pectin were optimised. By applying a response surface method, the influences of concentration of pectin, dry-heating treatment time, and dry-heating treatment temperature on starch anti-digestibility of sweet potato starches were analysed. The results showed that the optimal technological conditions were as follows: the content of pectin, dry-heating time, and dry-heating temperature were 2.18%, 2.09 h, and 121.73 °C, respectively. The RS content in sweet potato starches prepared under these conditions was within 18.48% ± 0.73%. The result obtained through differenti0al scanning calorimetry (DSC) revealed that the heat enthalpy (ΔH) of sweet potato starch increased from 2.475 to 3.698 J/g after being subjected to dry heating with pectin. Moreover, the result of in vitro digestibility tests suggested that the glycemic index of sweet potato RS prepared through dry heating with pectin was 69.09.

The effect of Asian Bullfrog (Rana tigerina) skin oil on the mycelium growth of pathogenic fungi, Colletotrichum gloeosporioides, was studied in vitro. A poisoned substrate technique method (dilution in solid media) was employed to evaluate the antifungal activity of the frog skin oil (FSO) at different concentrations (0–10%) against C. gloeosporioides. FSO showed an inhibitory effect, and the efficacy increased with increasing FSO concentration. A modified logistic model was applied to evaluate the antifungal activity of FSO at different concentrations. The modified logistic model showed a good agreement with the observed growth data for C. gloeosporioides. It can be concluded that FSO could potentially control the growth of C. gloeosporioides and that the modified logistic model could describe the inhibitory pattern of FSO against C. gloeosporioides effectively.

This study evaluated the survival of Listeria monocytogenes in kimchi using predictive models. Kimchi inoculated with L. monocytogenes was stored at 4, 15, and 25 °C, and the cells were enumerated on PALCAM agar. The Baranyi model was fitted to L. monocytogenes counts to calculate lag phase duration, maximum specific growth rate (µ_max; Log CFU/g/h) and death rate (DR; Log CFU/g/h). A polynomial equation was fitted to the kinetic parameters, followed by development of a dynamic model. While L. monocytogenes showed sparse growth at 4 °C, obvious growth was observed at 0.041 (15 °C) and 0.185 (25 °C) µ_max. After 96 (4 °C), 60 (15 °C), and 24 (25 °C) h, L. monocytogenes cells started to decrease at DRs of 0.023, 0.039, and 0.144, respectively, with an RMSE of 0.370, indicating appropriate performance of the models. These results indicate that L. monocytogenes can survive in kimchi, even when it is fermented sufficiently.

Sensory descriptors of mango ‘Ataulfo’ treated with dose of γ-rad (Cobalt 60) of 0, 0.15, 0.30, and 0.45 kGys were evaluated. Eight trained panelists evaluated eleven sensory descriptors, three on taste, four on texture and four on odor. Judges found significant differences (P < 0.05) for sweetness, sourness, astringency, juiciness, firmness, mango odor and honey odor in at least one treatment. The principal component analysis revealed a positively association between juiciness, mango odor, and honey odor with the irradiation dose of 0.30 kGy, besides the positively association between creaminess and the irradiation dose of 0.15 kGy. Any descriptors were influenced clearly by the radiation with dose at 0.45 kGy. Dose of 0.15 kGy of radiation can be used as phytosanitary treatment without substantially affecting the sensory properties of mango ‘Ataulfo’.

To reduce proteases in a commercial lactase preparation from K. lactis, enzyme preparations were diluted by a buffer with KCl and the dilutions were flushed through a weak anion-exchange membrane. For KCl concentration in the range of 0.20 to 0.25 M, more than 90% of lactase was recovered and protease level was decreased to less than 20%. Purified and pre-purified lactase solutions added in excess to milk and incubated for 3 months at 30 °C showed degraded milk protein bands on SDS-PAGE by treatment with the pre-purified lactase but not purified lactase. A one-step purification method for protease removal from the K. lactis lactase preparation was performed only by flushing the solution through an anion-exchange membrane.

We investigated the characteristic volatiles of purple potato using sensory evaluation, GC-MS and GC-O, and developed a flavoring formulation based on the information obtained from these tests to apply to potato products. The sensory analysis indicated that roasted and sourish notes gained the highest and lowest scores, respectively, but compositional analysis through GC-MS drew the opposite conclusion, namely that the compounds producing sourish notes accounted for the highest percentage (31.27%) in all volatiles while roasted notes took up the lowest proportion (5.16%). GC-O analysis was able to explain this phenomenon, as we identified 2,4-nonadienal, 2,4-decadienal, decanal and 3-octen-2-one as the characteristic volatiles of purple potato. Therefore, the flavor formulation applied to potato products contained higher roasted-note and burnt-note compounds (8.05% and 6.18%, respectively) and lower sourish-note compounds (0.05%), which helped to preserve the original flavors of the purple potato and increase the fine aroma and sweet flavor of potato products.

Aromatic amino acid metabolites, including aromatic pyruvates and aromatic lactates, have been shown to be antioxidants with high radical scavenging activity. We surveyed the occurrence and distribution of these metabolites in foods and beverages, focusing on fermented products. Lactic acid bacteria (LAB)-fermented products showed high concentrations of aromatic lactates and much lower concentrations of aromatic pyruvates, while yeast-fermented products showed relatively high levels of aromatic pyruvates. The results were in accordance with the production of aromatic lactates and pyruvates by LAB and Saccharomyces cerevisiae under standard experimental culture conditions. Our findings therefore indicate the importance of utilizing the metabolic activities of fermenting microorganisms for developing foods with beneficial functions.

The aims of this study were to identify fungal growth inhibitory substances in cheese prepared using crude enzymes from Hericium erinaceum MAFF 435060 exhibiting milk-clotting activity and elucidate the conditions under which these substances are produced. Fungal growth inhibition caused by fatty acids, such as butanoic, hexanoic, octanoic, decanoic, and 9-decenoic acids, released by lipase activity of crude enzymes during ripening was estimated. Notably, the amounts of butanoic, hexanoic, and octanoic acids in ripened cheese exceeded their minimum growth inhibitory concentrations for Aspergillus niger NBRC 105649. Growth inhibition and high fatty acid content were observed in cheese prepared using homogenized milk as raw material, although homogenized milk in which milk fat was not encapsulated within the globule membrane was required. These results suggested that the use of crude enzymes from H. erinaceum MAFF 435060 may allow the production of cheese with a prolonged shelf life.

A great deal of attention has been paid to preparation of bioactive peptides from proteins through enzymatic hydrolysis. Enzymatic hydrolysates of diverse food proteins exert various biological activities. In the present study, we prepared and characterized Grifola frondosa protein hydrolysate (GFPH)-selenium chelating complex. Moreover, we assessed the effects of four main independent variables of the chelation conditions and selenium-binding capacity using response surface methodology (RSM). According to the results of RSM, the optimal chelation conditions were as follows: reaction time of 90 min, reaction temperature of 45 °C, pH of 9.0 and the ratio of hydrolysates to sodium selenite (v:v) of 6:4. The content of selenium reached 2 979.45 ± 8.77 µg/g under the optimal conditions. Results of Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible (UV) spectroscopy indicated the successful incorporation of selenium into GFPH. The analyses of hydroxyl radical scavenging ability and ferric ion reducing antioxidant power (FRAP) were used to evaluate the antioxidant abilities of the newly synthesized chelate. Results showed that the antioxidant activities of GFPH-Se were superior to GFPH. The results of cellular uptake of GFPH-Se chelate in Caco-2 cells suggested that GFPH-Se chelate could be used as a potential source of Se supplement. Taken together, our findings indicated that the by-product of Grifola frondosa was a promising source for peptide-Se bio-products, which could be used as fungus-based functional supplements for humans with Se deficiency.

Mayonnaises and dressings are preferred seasonings, and a variety of such products are available on the market. Six mayonnaises, three salad creamy dressings, one oil-in-water (O/W) type semisolid dressing, and one water-in-oil-in-water (W/O/W) type semisolid dressing, all of which are commercially available, were frozen at −20 °C, −23 °C, −25 °C, −28 °C, and −80 °C for specified time periods and then thawed at about 25 °C. The changes in temperature of the mayonnaises and dressings during freezing and thawing depended on their types. Oil-water separation was observed after thawing for all mayonnaises, except when rapidly frozen at −80 °C. Up to 60% of the oil phase contained in the dressings separated after thawing, suggesting that thickeners added to the aqueous phase partially suppressed the oil-water separation. The temperature changes and oil-water separation behaviors of the W/O/W type semisolid dressing were similar to those of the mayonnaises.

The pullulanase and α-glucosidase in brown rice is predominately found in the endosperm of rice grains of Koshihikari and Nipponbare cultivars. However, the exact localization of these enzymes in the endosperm layers is not clear. To investigate enzyme localization in non-glutinous brown rice, immuno-fluorescence detection of these enzymes was carried out using frozen sections of rice grains (Koshihikari, Nipponbare and Milkyqueen cultivars). While pullulanase-like immuno-reactivity was dominantly detected in amyloplasts, α-glucosidase-like immuno-reactivity was mainly detected along endosperm cell walls among the three non-glutinous cultivars. Immuno-reactivity of both enzymes overlapped in the aleurone layer and embryo among the three cultivars. During rice cooking, pullulanase-like immuno-reactivity partly overlapped with α-glucosidase-like immuno-reactivity along endosperm cell walls among the three cultivars. These results indicate that each enzyme has a unique localization, and these unique localizations are common among the three non-glutinous cultivars.

It has been suggested that patients with cow's milk allergy can ingest baked milk without adverse reactions, although this has not been characterized sufficiently. Here, we investigated the solubility, allergenicity, and digestibility of αs1-casein and β-lactoglobulin when skim milk (SM) was mixed with food ingredients, starch and gluten, and then baked. Samples were analyzed using competitive ELISA, SDS-PAGE, and immunoblot. The protein bands of cow's milk proteins (CMP) in baked SM with starch and gluten were shifted up. αs1-Casein and β-lactoglobulin in the PBS extract from the baked SM with gluten decreased compared with that in the baked SM with starch. αs1-Casein and β-lactoglobulin were detected as insoluble fractions. The allergenicity of CMP was significantly decreased by baking and when mixed with gluten. The digestibility of αs1-casein and β-lactoglobulin was unaffected by food ingredients, and insolubilized β-lactoglobulin was not digested and thus remained, especially in baked SM with gluten.

Lactobacillus paracasei MCC1849 (LP) has the potential to modulate immune function. The purpose of this study was to investigate the impact of flavor compounds on changes in sensory characteristics during refrigerated storage of a functional LP-fermented dairy beverage. A sample containing 1 × 10⁸ cells/mL viable LP stored at 10 °C for 0, 1, or 2 weeks was evaluated by a trained panel. The scores for ‘odor’, ‘afterflavor of fermented odor’, ‘fermented odor’, and ‘acidity’ increased significantly. Three types of gas chromatography-mass spectrometry for volatiles in the solvent extract and headspace gas, and also for hydrophilic compounds were performed. The compounds related to the change in four sensory attributes were examined by partial least squares regression analysis. A non-stored sample with a flavor composed of 13 compounds related to the attributes replicated the fermented odor characteristics of the 2-weeks-stored sample.

Background: β-Glucans reportedly inhibit gastric ulceration; however, it is unclear which form of the polysaccharide is important for this inhibitory effect. In this study, the effect of paramylon from Euglena gracilis (β-(1,3)-glucan) on gastric ulcers was evaluated. Materials and methods: Wistar rats were exposed to water-immersion restraint stress (WIRS). Results: Dietary intake of Euglena extract powder, paramylon (insoluble), and amorphous paramylon (soluble) decreased the area of gastric ulceration in comparison with the control group. WIRS-induced increases of inducible nitric oxide synthase expression in the gastric mucosa and serum IgA and alanine aminotransferase levels were suppressed in rats fed with Euglena extract powder, paramylon, or amorphous paramylon. These results indicate that paramylon and amorphous paramylon suppressed gastric ulcers, presumably by reducing oxidative damage resulting from WIRS. In addition, our data suggest that Euglena extract powder, paramylon, and amorphous paramylon prevent the WIRS-induced influx of proinflammatory molecules from the gut.

Complete plasticization of starch granules plays an important role in maximizing the properties of a starch film. Ultrasonication treatment is one way to achieve this by breaking up insoluble starch grains. This study reports on the effects of ultrasonication on the characterization of bengkoang (Pachyrhizus erosus) starch films. Starch gel was sonicated using an ultrasonic probe at 66.9 W/cm² for 4 min. SEM of the fracture surface of the sonicated film showed a more compact structure than for the non-sonicated or control film. The sonicated films displayed a lower opacity than the control film. Opacity of the sonicated film was 6.82% lower than control film. The sonicated film also had lower hydrophilicity; moisture absorption of film was decreased about 10.28% after sonication. Furthermore, ultrasonication increased the tensile strength and decreased the fracture strain of films.

In this study, we investigated the antioxidant activities and taste qualities of fresh onions produced in the Minamishimabara city, Nagasaki, Japan. Samples were ‘Super-Up’ (SU), a conventional cultivar, and ‘Kazusa No. 13’ (K13), a new cultivar, and these were compared with ‘Shippowase No. 7’ (S7), a general-use cultivar. The total oxygen radical absorbance capacity of K13 was higher than that of S7. The 1, 1-diphenyl- 2-picrylhydrazyl free radical-scavenging activity and the total quercetin concentration were higher in SU and K13 than in S7. Umami and saltiness values (determined using the Taste Sensing System) and total free amino acid concentrations in SU and K13 were lower than those in S7, with the differences in total free amino acid concentration contributing to the difference in taste responses between the onion cultivars. Total sugar concentration in SU was lower than in S7. These results suggest that the advantages of SU and K13 were in terms of high levels of antioxidant activity and quercetin concentration, rather than in terms of taste or flavor. Thus, onions of cultivars SU and K13 are expected to be new regional brand foods of Nagasaki, targeted at health-conscious consumers.