Time filter

Source Type

Konishi Y.,Hokkaido Industrial Technology Center | Kobayashi M.,Hokkaido University of Science
Chemical Engineering Transactions | Year: 2010

A hybrid method of chemical engineering and proton NMR technique was effectively applied to design a variety of commercially produced meat-jerkies. For the actual application of the hybrid method, twelve commercial meat-jerkies, 6 pork- and 6 beef-samples, were tested. The samples were widely characterized by variety of seasoning such as salt, soy sauce, smoke etc. The design parameters chosen for the 12 samples were four derived from the chemical engineering as moisture content (Wo, %-d.b.), effective moisture diffusivity (De, m2/s), activation energy of De (ED kJ/mol), and hardness (NP, Newton/m2), and two derived from the proton NMR technique as correlation time (τc s) and critical value of τc(cτc). To characterize the 12 jerkies, three design parameters, Wo, De and Np were evaluated as a function of τc. The three parameters commonly demonstrated the existence of two different water species which was divided at the critical value of τc(cτc=1.0×10 -8s), called as water species-A, (τc < l×10-8s) and -A2(τc > l×10-8s). τc contributes to both the hardness (Np) of the jerky's meat tissues and moisture mobility (De) in the jerky's muscle, both of which were strongly related to the specified seasoning used. Based on the dynamism of the three parameters, Wo, De and Np as a function of τc derived from the hybrid method, one could recognize all jerkies to be designed by using the water species-A2. It could be understood that the specified character appeared in the commercially distributed meat jerky products was reasonably designed by dynamically changing the value of τc. The 12 jerkies were characteristically classified into five groups by using a specified combination among the values of the four design parameters, De, Np, Wo, and τc. Copyright © 2010, AIDIC Servizi S.r.l.

Konishi Y.,Hokkaido Industrial Technology Center | Kobayashi M.,Hokkaido University of Science
Chemical Engineering Transactions | Year: 2012

The Maillard reaction in foods has been studied by using a computer simulation technique. As a typical model system, the dehydration process of an ordinary leek was effectively used to demonstrate an optimum drying operation. The Maillard reaction rate of the leek has been measured as a color change using a commercially prepared color meter. To evaluate the color change of the leek, a color parameter of ΔE* (=((Δa*) 2+(Δb*)2+(ΔL*)2) 1/2) was chosen because it followed a good linear relation with the dehydration response curve of the leek. The response curves of ΔE* obtained in the dehydration operation were described by a typical consecutive reaction model A→B→C, where A is glucose-like materials contained in the leek, B is intermediates formed, and C is melanoidin-like materials as final products. The computer simulation fitting to both the experimental dehydration response curves of CC and the ΔE*-value response curves evaluated the maximum amount of CB (CBmax). The integrated amount of CB (CBin) produced in the course of the dehydration process changed appreciably depending on the drying temperature and the humidity of the drying air. This took place because the water species dynamically shifted from species A1 (weakly restricted water species in the A1 region of W0 = 1600∼120 %-d.b.) to A 2 (strongly restricted water species in the A2 region of W0 = 120∼20 %-d.b.) at the water content of W0 = 120 %-d.b. The sensory scores, evaluated by both the four human tasters and a commercially distributed taste tester as a function of CBin, gave a gradual increase curve indicating the larger CBin to be the higher taste score. A two-step dehydration, using the 70 °C-operation in the water species A1 region and the 40 °C - operation in the water species A2 region, was recognized as an optimized operation for the best sensory score product. Copyright © 2012, AIDIC Servizi S.r.l.

Konishi Y.,Hokkaido Industrial Technology Center | Kobayashi M.,Hokkaido University of Science
Drying Technology | Year: 2016

The dualism of the hydration water in seven foods was visualized, focusing on both water diffusivity (De, m2s−1) and apparent molecular mobility (T2, relaxation time, s). On the pre-exponential factor (δDe0) of De, the compensation effects between ln(δDe0) and the activation energy (ED) of De demonstrated the difference in the water diffusion mechanisms among the foods. On the values of T2 at the self-organized temperature (1/T) of hydration water, it yielded a common compensation effect between ln(T2) and the activation energy (ESO) of self-organization, demonstrating a common self-organization mechanism. © 2016, Copyright © Taylor & Francis Group, LLC.

Konishi Y.,Hokkaido Industrial Technology Center | Kobayashi M.,Hokkaido University of Science | Miura K.-I.,Kitami Institute of Technology
International Journal of Food Science and Technology | Year: 2010

For the discrimination of water molecules during the squid-drying process, the water distribution was characterised by water proton NMR and moisture diffusivity (De) analysis methods as a function of the water content (W0). The proton NMR spectrum showed three peaks indicating three different species (species-A, -B, and -C) distributed in the squid muscle, each of which had a characteristic behaviour of the relaxation time (T2) as a function of the W0. The 1/T2 of species-A was drastically varied at W0 = 120%-d.b., indicating two further categories, i.e., species-A1 and -A2. Species-A1 is available at W0 > 120%-d.b. and was characterised as having De = 5.1 × 10-10 m2 s-1, activation energy of moisture diffusivity (ED) = 17 kJ mol-1, and relaxation rate 1/T2 = 74 s-1, as evaluated by the proton NMR spectrum without depending on W0. Species-A2 is available at W0 < 120%-d.b., indicating a distribution of De = 4.8 × 10-10-1.7 × 10-10 m2 s-1, ED = 25-35 kJ mol-1 and 1/T2 = 1.8 × 103-1.5 × 102 s-1 with increasing W0. Species-A1 and -A2 were assigned as weakly restricted water and strongly restricted water, respectively. © 2010 The Authors. Journal compilation © 2010 Institute of Food Science and Technology.

Inoue A.,Hokkaido University | Takadono K.,Hokkaido University | Nishiyama R.,Hokkaido University | Tajima K.,Hokkaido University | And 2 more authors.
Marine Drugs | Year: 2014

A major alginate lyase, FlAlyA, was purified from the periplasmic fraction of an alginate-assimilating bacterium, Flavobacterium sp. strain UMI-01. FlAlyA showed a single band of ∼30 kDa on SDS-PAGE and exhibited the optimal temperature and pH at 55 °C and pH 7.7, respectively. Analyses for substrate preference and reaction products indicated that FlAlyA was an endolytic poly(mannuronate) lyase (EC A gene fragment encoding the amino-acid sequence of 288 residues for FlAlyA was amplified by inverse PCR. The N-terminal region of 21 residues except for the initiation Met in the deduced sequence was predicted as the signal peptide and the following region of six residues was regarded as propeptide, while the C-terminal region of 260 residues was regarded as the polysaccharide-lyase-family-7-type catalytic domain. The entire coding region for FlAlyA was subjected to the pCold I-Escherichia coli BL21(DE3) expression system and ∼eight times higher yield of recombinant FlAlyA (recFlAlyA) than that of native FlAlyA was achieved. The recFlAlyA recovered in the periplasmic fraction of E. coli had lost the signal peptide region along with the N-terminal 3 residues of propeptide region. This suggested that the signal peptide of FlAlyA could function in part in E. coli. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Discover hidden collaborations