RESUMEN
Due to the high demand (consumers and regulatory authorities) on elimination or reduction of 'additives' in food and other health related products, there is increasing interest on natural macromolecules or hydrocolloids such as gums. Gum Tragacanth (GT) is a multifunctional exudate gum with unique thickening, emulsifying, viscosity improving, stabilizing, gelling and structuring capabilities. Owing to its distinctive functionality, it has been extensively used in low-fat or non-fat food formulations, colloid-based products, edible films and coatings and (nano) encapsulation of food ingredients. This review provides the comprehensive information on its physicochemical, structural and functional characteristics with a particular focus on its application in foods.
Asunto(s)
Gomas de Plantas/química , Tragacanto/química , Biopolímeros/química , Coloides/química , Emulsiones , Alimentos , Industria de Alimentos , Ingredientes Alimentarios , Estructura Molecular , Aceites Volátiles/química , Gomas de Plantas/biosíntesis , Reología , Espectroscopía Infrarroja por Transformada de Fourier , Relación Estructura-Actividad , Tragacanto/biosíntesisRESUMEN
The oil extracted from Crotalaria juncea (Sunn-hemp) contains 70% of gum. Several methods of degumming are attempted in order to maximize the yield of gum. During appropriate water induced degumming, about 95-98% of phosphatides are separated. The maximum oil yield for two types of degummimg processes are 0.59% and 0.69% corresponding to hot water and pure O-phosphoric acid (19.88â¯N) treatment respectively. The % oil yield obtained for TOP degumming is about 0.78%. Physico-chemical characteristics of the isolated gum such as moisture, ash, protein, fat and aqueous solubility along with FTIR and TGA analysis are studied in order to evaluate the effect of extraction process. The behaviour of gum on the molecular scale is evaluated through alcohol treatment. Chromatographic analysis determines the monosaccharide content of the gum with glucose: xylose: arabinose::54: 34:1. Rheological characterization shows that the juncea gum solutions are shear rate dependent and the behaviour is shear-thinning (or pseudoplastic). Results show that the temperature dependent viscosity decreases with increasing shear rate.
Asunto(s)
Crotalaria/química , Gomas de Plantas/química , Reología , Semillas/química , Arabinosa/química , Glucosa/química , Gomas de Plantas/biosíntesis , Viscosidad , Agua/química , Xilosa/químicaRESUMEN
Ferula gummosa Boiss. is an industrial and pharmaceutical plant that has been highly recognized for its valuable oleo-gum-resin, namely galbanum. Despite the fabulous value of galbanum, very little information on the genetic and biochemical mechanisms of its production existed. In the present study, the oleo-gum-resin and four organs (root, flower, stem, and leaf) of F. gummosa were assessed in terms of metabolic compositions and the expression of genes involved in their biosynthetic pathways. Results showed that the most accumulation of resin and essential oils were occurred in the roots (13.99 mg/g) and flowers (6.01 mg/g), respectively. While the most dominant compound of the resin was ß-amyrin from triterpenes, the most abundant compounds of the essential oils were α-pinene and ß-pinene from monoterpenes and α-eudesmol and germacrene-D from sesquiterpenes. Transcriptome analysis was performed by RNA sequencing (RNA-seq) for the plant roots and flowers. Differential gene expression analysis showed that 1172 unigenes were differential between two organs that 934 (79.6%) of them were up-regulated in the flowers and 238 (20.4%) unigenes were up-regulated in the roots (FDR ≤0.001). The most important up-regulated unigenes in the roots were involved in the biosynthesis of the major components of galbanum, including myrcene, germacrene-D, α-terpineol, and ß-amyrin. The results obtained by RNA-Seq were confirmed by qPCR. These analyses showed that different organs of F. gummosa are involved in the production of oleo-gum-resin, but the roots are more active than other organs in terms of the biosynthesis of triterpenes and some mono- and sesquiterpenes. This study provides rich molecular and biochemical resources for further studies on molecular genetics and functional genomics of oleo-gum-resin production in F. gummosa.
Asunto(s)
Ferula/genética , Metaboloma , Gomas de Plantas/biosíntesis , Transcriptoma , Ferula/metabolismo , Flores/genética , Flores/metabolismo , Regulación de la Expresión Génica de las Plantas , Aceites Volátiles/metabolismo , Gomas de Plantas/genética , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Terpenos/metabolismoRESUMEN
Partially hydrolyzed guar gum (PHGG), an important supplemental dietary fiber, has been used as food ingredient in many industries. In this study, a novel ß-mannanase gene (RmMan5A) from Rhizomucor miehei was successfully expressed in Pichia pastoris and subjected for PHGG production. Enzyme activity of fermentation supernatant reached 85,200UmL-1 after 168h high cell density fermentation. The purified RmMan5A exhibited the highest enzyme activity at pH 7.0 and 65°C. RmMan5A was then employed for guar gum hydrolysis and PHGG obtained demonstrated a weight-average molecular weight (Mw) of 2.5×104Da. Total dietary fiber accounted 90.6% of PHGG and 24.9% (w/w) of PHGG were identified as manno-oligosaccharides with degree of polymerization<7. PHGG was further fractionated (F1-F4) by gradual ethanol precipitation. PHGG F1 with an Mw value of 3.6×104Da and a mannose/galactose (M/G) ratio of 1.47 was precipitated initially, followed by PHGG F2 and F3 which showed lower Mw and higher M/G ratio. According to the structure analysis, the distribution of α-d-galactose of PHGG F1 was compact and regular, and that of other fractions was more random. A suitable ß-mannanase for PHGG production and some useful information of PHGG are provided in this paper.