Application Of Konjac Glucomannan Research Articles

Application of Konjac Glucomannan with Chitosan Coating in Yellow Alkaline Noodles.

To improve the quality of the characteristics of yellow alkaline noodles and enrich their nutritional value, konjac glucomannan (KGM) with or without chitosan coating were added to noodles, and their application effects were investigated in terms of color, texture, water absorption, starch digestion, total plate count (TPC) and microstructure. Chitosan-konjac glucomannan (CK) complex was firstly prepared by embedding konjac powder with chitosan sol. After embedding, the hydrophilicity of KGM decreased significantly. Then, either CK or native KGM were mixed evenly with flour before saline water, and soda was subsequently added to produce noodles. Compared with native KGM, CK provided the noodles with a higher brightness and a lighter yellow color. In terms of texture properties, although the firmness of CK noodles was weaker than that of KGM noodles, the tensile properties were enhanced. After embedding, the water absorption of CK noodles decreased and the content of resistant starch (RS) in the noodles increased. During storage, the TPC in CK noodles was significantly lower than that in KGM noodles. At a CK content of 5%, the noodles presented a lightness of 87.41, a b value of 17.75, a shear work of 39.9 g·cm, a tensile distance of 84.28 cm, a water absorption of 69.48%, a RS content of 17.97% and a TPC of 2.74 lg CFU/g at 10 days. In general, KGM with chitosan coating could improve the physicochemical qualities of noodles and extend their shelf life to a certain extent.

Combined effect of konjac glucomannan addition and ultrasound treatment on the physical and physicochemical properties of frozen dough

The effects of dual sequential modification using konjac glucomannan and ultrasound treatments at power densities of 15–37.5 W/L on the hydration, rheology and structural characteristics of frozen dough were investigated in this study. The results revealed that the konjac glucomannan and ultrasound treatments improved the textural properties of frozen dough, but had a negative impact on its viscoelasticity. Furthermore, konjac glucomannan and ultrasound treatments increased the content of free sulfhydryl group and disulfide bond, as well as improved the freeze tolerance of dough. The results exhibited that the enthalpy of frozen dough decreased by 20.42 % compared with the frozen blank control dough under ultrasonic power density of 22.5 W/L. The network structure of frozen dough treated by konjac glucomannan and ultrasound was more ordered and integral than that of frozen blank control dough. These results provide valuable knowledge on the application of konjac glucomannan and ultrasound to frozen wheat-based foods.

Effect of konjac glucomannan with different viscosities on the quality of surimi-wheat dough and noodles

It was investigated that the rheology, starch-gluten-surimi network, thermal properties, and water distribution of surimi-wheat dough, and texture characteristics, cooking properties, and microscopic characteristics of the surimi-wheat noodles with konjac glucomannan (KGM) of different viscosities in different concentrations. The results showed that the storage (G′), loss (G″), and complex (G⁎) moduli of dough increased with adding KGM. With the increase of KGM viscosity, the reduction in the free sulfhydryl (SH) content to 0.84 μmol/g and the increase in the free water content to 8.25 % led to significantly improved enthalpy and the microstructure density. The hardness and tensile length of noodles were substantially increased by adding 3 % KGM. In addition, the KGM enhanced the starch-gluten-surimi network and improved the cooking qualities and textural properties of noodles. More importantly, the application of KGM in the wheat flour composite system also showed better performance. Thus, the introduction of KGM into the surimi-wheat dough had a significant effect on the optimization of the macro- and micro-characteristics of dough and noodles.

Influence of konjac glucomannan on thermal and microscopic properties of frozen wheat gluten, glutenin and gliadin

The effects of different konjac glucomannan (KGM) concentrations (0.5%, 1.5%, 2.5%, 3.5%, 4.5%, w/w) on the thermal and microscopic properties of the frozen wheat gluten, glutenin and gliadin were investigated in this study. KGM exerted a positive effect on the denaturation temperature and denaturation enthalpy of frozen gluten and gliadin, while KGM decreased those of frozen glutenin. Such effects induced by KGM were resulted from the interaction between KGM and frozen wheat gluten, glutenin and gliadin. The underlying mechanism was discussed from the perspective of protein structure. Specifically, the addition of KGM increased the α-helix structure of frozen gluten and gliadin, while decreased the α-helix of frozen glutenin. Furthermore, β-turn of frozen gluten and gliadin presented a decreasing trend with increasing amount of KGM. Scanning electron microscopy confirmed that there was stronger interaction between wheat protein and KGM. These results provide fundamental knowledge for better application of KGM in frozen protein-based foods.

Synergistic degradation of konjac glucomannan by alkaline and thermal method

The application of konjac glucomannan (KGM) in the food industry is always limited by its high viscosity. Hereby, low-viscosity KGM was prepared by alkaline-thermal degradation method. This process was demonstrated by the changes of average molecular weight and a kinetic model was developed. The results revealed that high alkalinity and high temperature had a synergetic effect on degradation. The structure of hydrolysates was evaluated by periodate oxidation and their fluidly properties were researched by rheology measurements. The degradation was divided into two regimes. The rate of the first regime (within 1h) is higher than that of the second one (last 1h). It is found that alkaline hydrolysis and deacetylation have a synergistic effect on the degradation under high alkalinity (pH 9.2) and low temperature condition (25°C). Finally, rheology parameters showed alkaline-thermal degradation is a promising way that can be applied in practice to degrade KGM.

Study on Shear Rheological Behavior of Konjac Glucomannan

Konjac glucomannan (KGM) belongs to pseudoplastic fluid. Remarkable non-linear change tendencies of shear rheological behavior of KGM were detected through analysis of the correlation of viscosity (η)-shear rates and shear stress-shear rates respectively, and its shear rheological curves conformed to the Power Law (τ=ＫDn). The change tendencies of viscosity factor (K) and flow index (n) correlated with concentration and temperature were also obtained, the curves can be fitted by power and quadratic polynomial equation respectively. The acquired non-linear correlation curves of K and n can provide reliable foundation for rational applications of KGM in food industry and its grade estimation.

An investigation into the application of konjac glucomannan as a flavor encapsulant

The application of konjac glucomannan (KGM) in flavor encapsulation in the spray-dry method was investigated in this paper using sweet orange oil as the model. KGM provided the highest encapsulation yield when the apparent viscosity of the KGM solution was reduced to 200 mPa S by cellulase hydrolysis. In the presence of emulsifier Tween 80, the hydrolyzed KGM offered comparable encapsulation yield with Arabic gum and starch sodium octenyl succinate (SSOS), but provided significantly higher encapsulation yield than maltodextrin. Besides, the combination of KGM with Arabic gum, SSOS, and maltodextrin, were also studied. The combination could significantly (P < 0.05) increase the encapsulation yield in the KGM content up to 80% compared with pure KGM; when the KGM content was reduced to 20%, the combination with maltodextrin resulted in a significant (P < 0.05) decrease in encapsulation yield, possibly due to the poor emulsifying capability of both KGM and maltodextrin. The effect of encapsulation on flavor composition was investigated by using the fingerprint technique and the vectorial angle method was adopted to assess the similarity between the chromatographs. The comparison showed that KGM had similar flavor retention with SSOS and Arabic gum, but provided a significant (P < 0.05) higher retention than maltodextrin. The encapsulated flavors exhibited few pores and smooth surface under TEM with the size ranging from 5 to 15 μm. It was concluded that KGM provided comparable flavor retention capability as the most widely used Arabic gum and SSOS and had great potential as a flavor encapsulant.

Advance in the applications of konjac glucomannan and its derivatives

Konjac glucomannan is a kind of neutral polysaccharides with excellent biocompatibility and biodegradable activities. The recent studies on the applications of konjac glucomannan and its derivatives in pharmaceutical, bio-technical, fine chemical fields etc. were reviewed.