Rheological Properties and Sugar Composition of Locust Bean Gum from Different Carob Varieties (Ceratonia siliqua L.) (original) (raw)
Related papers
2017
The present work aims at bringing new insights into the galactomannan physicochemical characteristics through an unprecedented approach: relationship between the morphology of carob seeds and corresponding gums chemical and physical properties. Therefore, four commercial carob seeds with different granulometries were studied. Their endosperms (Locust bean gum, LBG) were evaluated in term of yield, chemical composition, sugar composition and macromolecular and rheological properties. Acid dehulling furnished a gum yield in the range of 39.4-42.0%. The greater size of the seeds allowed an easier dehulling and a production of more and purer gum flour. The viscosity of 1% LBG aqueous solutions varied widely from 903 to 2081 mPas and appeared to be influenced by the seed size. The mannose to galactose ratio, of the extracted gums, did not show clear difference that may explain the difference in viscosity. However, the macromolecular size values for intrinsic viscosity [η] and radius of g...
Carbohydrate Polymers, 2007
In this study the composition of higher quality refined locust bean gum (rLBG) was compared with lower quality crude locust bean gum (cLBG) samples to understand the differences in functionality. M/G ratio has a great bearing on the viscosity and gelling properties of the material. The values obtained for M/G ratio of cLBG and rLBG samples range from 3.1 to 3.9, respectively, however high levels of arabinose were found in cLBG. This indicates that other polysaccharides, which could contain galactose or mannose, are present in the less refined materials. This would question the accuracy of using M/G ratio of cruder seed gums as a tool for predicting galactomannan content and so gelling properties. cLBG also contained higher levels of protein, fat, and ash which could also have an effect on functionality.
The carob product most widely used, especially for the food industry, is the carob bean gum (CBG), or locust bean gum (LBG). This gum comes from the endosperm of the seed and chemically is a polysaccharide, a galactomannan. It is used as thickener, stabilizer, emulsifier and gelling agent. This study was carried out to determine and to compare the characteristics of LBG in terms of yield, moisture and ash content and protein content. Samples were collected from different regions in the agro-forestry system of Morocco. The results showed that the Moroccan cultivars are characterized by a high yield of seeds that provide a high yield of endosperm. The purified CBG from different population of Moroccan carob tree had 60.63–72.49% yield, 6.36– 8.63% moisture, 0.36–0.99% ash and 0.52–0.62% protein. The protein, moisture and ash, and the yields of purified locust bean gum are comparable to those reported in the literature from other countries. Keywords: Carob pulp; Carob seeds; Carob bean...
Carbohydrate Polymers, 1999
The behaviour, during thermal processing, of a higher quality analytical-grade (AG) locust bean gum (LBG) was compared with a lower quality technical grade (TG) LBG. The TG material contained a substantial amount of material (40%) of dry weight, which remained insoluble after heating to 70ЊC. Sugar analysis suggests that this insoluble material contained high levels of arabinose. The TG material showed low viscosity throughout the heating cycle and lower levels of degradation at high temperatures, as evidenced from viscosity measurements. The reason for this could have been that, in these samples, the viscosity is dominated by the non-soluble particulates in the system; however, on removal of particulates further rheological studies, made at comparable galactomannan concentrations, also showed differences between the degradation of the AG and TG LBG. Despite the difference in behaviour through the heating cycle, at equal galactomannan levels, the AG and TG materials had similar viscosities at the end of this cycle. This may explain why, after heat processing, the TG material interacts synergistically with carrageenan in a similar way to AG locust bean gum. ᭧
A comparison between the hot and cold water soluble fractions of two locust bean gum samples
Carbohydrate Polymers, 1986
Locust bean gum extracted from two carob flours from eastern and western Mediterranean sources were fractionated on the basis of their solubility in water. Weight-average molecular weights determined by sedimentation equilibrium were about 300 000 for both the hot water and cold water soluble fractions, whereas a commercial sample of guar gum had a molecular weight of 700 000. Their values were lower than would be predicted from Mark-Houwink relationships where molecular weights were originally determined by light scattering.
Food and Nutrition Sciences, 2015
In this research, locust bean gums were removed from seeds with different extraction methods and some physicochemical properties were analyzed for gums and also locust beans. Three different extractions were treated at different temperatures and durations of sulfuric acid (H 2 SO 4 , 60%) solution, hydrochloric acid (HCl, 30%) solution and boiling water. Following dehulling and drying processes, seeds were milled and locust bean gums (LBG) were obtained eventually. The color values, moisture, protein, ash, sugar, pH, total acidity, soluble solids content, foreign particulates, acid insoluble ash contents and viscosity curves were compared for all samples. The results exhibited that the highest ash (1.94%) and protein (6.65%) contents were determined by water extraction gum, the highest acid-insoluble ash (3.58%) and foreign particulates (44.17%) contents were determined by HCl extraction gum. The lowest protein (5.01%), acid insoluble ash (1.29%), the foreign particulates (34.99%) and the highest viscosity value (533.9 mPas) were found from H2SO4 extraction gum. The results of investigation also showed that the H 2 SO 4 extraction method was found to be more appropriate than HCl and water extraction methods to obtain a good quality gum.
The structural characteristics and rheological properties of Lebanese locust bean gum
Journal of Food Engineering, 2014
After formation of the ovalbumin (OVA)-gum arabic (GA) complex coacervates, a more ordered crystal structure was obtained, and the protein denaturation temperature increased from 72 to 96°C. GA can reduce the pHinduced conformational perturbations of ovalbumin. The presence of GA improved the stability of the α-helix and β-turn regions against pH, but showed less influence on the random coil and β-sheet domains. The complex coacervates showed the highest viscosity value at pH 3.7 compared with the other pH values tested (4.0, 3.4, 3.0, 2.7) due to the stronger interactions of OVA and GA. A large thixotropic loop was observed for the coacervate obtained at pH 3.7 compared with that obtained at pH 4.0. Moreover, the salt concentration and OVA:GA ratio influenced the rheological properties by affecting the structure and composition of the complexes. A stronger interaction between OVA and GA led to greater viscoelastic properties.
Morphological and Technological Characterization of Different Carob Cultivars in Sicily
Acta Horticulturae, 2012
Carob (Ceratonia siliqua L.), is a legume tree species diffused in marginal dry areas of Mediterranean basin; carob tree has been long considered a neglected and underutilized species, but the crop is gaining popularity, since the flour extracted from the seeds (Locust Bean Gum, LBG) is used in food industry as thickening agent classified in the European Codex (E410). Nowadays several cultivars are cultivated in various Mediterranean countries showing high variability of morphological and technological properties of their fruits. Pods and seeds characterization appears to be important for the improvement of the business generated by carob products. For this reason 5 female ('Ibla', 'Latinissima', 'Pasta', 'Racemosa', 'Ruta') and 3 hermaphrodite genotypes ('Ramillete', 'Sangimignana', 'Tantillo') of different origin have been characterized. Fruits collected from mature plants have been used for morphological characterization; seeds have been extracted and evaluated in terms of yield, rheological properties, and sugar composition of the endosperm also in comparison with those of commercial samples coming from abroad. The viscosity of 1% LBG aqueous solutions was measured at different shear rates at pH 4.5 and 25°C. Results gave remarkable indications for some cultivars concerning seed number, weight and yield. LBG analysis of the samples showed statistical differences between the cultivars: the seeds of the Italian cultivars 'Ibla' and 'Racemosa' and those coming from Morocco showed the best yield, the latter standing out also for their high technological potential. The results confirm the high level of intraspecific variability in terms of seed yield, sugar composition of the endosperm, as well as thickening properties.
Journal of the Science of Food and Agriculture, 2000
After formation of the ovalbumin (OVA)-gum arabic (GA) complex coacervates, a more ordered crystal structure was obtained, and the protein denaturation temperature increased from 72 to 96°C. GA can reduce the pHinduced conformational perturbations of ovalbumin. The presence of GA improved the stability of the α-helix and β-turn regions against pH, but showed less influence on the random coil and β-sheet domains. The complex coacervates showed the highest viscosity value at pH 3.7 compared with the other pH values tested (4.0, 3.4, 3.0, 2.7) due to the stronger interactions of OVA and GA. A large thixotropic loop was observed for the coacervate obtained at pH 3.7 compared with that obtained at pH 4.0. Moreover, the salt concentration and OVA:GA ratio influenced the rheological properties by affecting the structure and composition of the complexes. A stronger interaction between OVA and GA led to greater viscoelastic properties.