With the world continuing to push toward modernization and the consumption of processed foods growing at an exponential rate, the demand for texturizing agents and natural additives has also risen as a result. It has become increasingly common to use thickening agents in food products to modify their rheological and textural properties and enhance their quality characteristics. They can be divided into (1) animal derived (chitosan and isinglass), (2) fermentation produced (xanthan and curdlan), (3) plant fragments (pectin and cellulose), (4) seaweed extracts (agar and alginate), and (5) seed flours (guar gum and locust bean gum). The primary functions of these materials are to improve moisture binding capacity, modify structural properties, and alter flow behavior. In addition, some have another responsibility in the food sector, such as the main ingredient in the delivery systems (encapsulation) and nanocomposites. A galactomannan polysaccharide extracted from guar beans (Cyamopsis tetragonolobus), known as guar gum (GG), is one of them, which has a wide range of utilities and possesses popularity among scientists and consumers. In the world of modernization, GG has found its way into numerous industries for use in food, cosmetics, pharmaceuticals, textiles, and explosives. Due to its ability to form hydrogen bonds with water molecules, it imparts significant thickening, gelling, and binding properties to the solution as well as increases its viscosity. Therefore, this study is aimed to investigate the characteristics, mechanisms, and applications of GG in different food technologies.

Doi:10.3906/biy-1304-64 Defense enzyme activities and biochemical variations of Pelargonium zonale in response to nanosilver application and dark storag

Application of nanotechnology is now widely distributed overall the life, especially in agricultural systems. This study intended to indicate the impacts of nano-sized titanium dioxide particles (NT) and bulk (BT) on antioxidant enzymes activities including superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT), and variations of two major tropane alkaloids such as hyoscyamine (HYO) and scopolamine (SCO) in Hyoscyamus niger L. Plants were treated with different concentrations of NT and BT (0, 20, 40 and 80 mg l-1). Alkaloids extracted were identified by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis. Results showed that SOD activity increased with increasing titanium dioxide concentration in both nano-particles and bulk treated plants. However, the highest and the lowest POX activity were observed in plants exposed to NT at 40 mg l-1 and control, respectively. Generally, all tested enzymes activities were higher in NT treated plants that those of BT except CAT activity at 80 mg l-1. The highest alkaloids content values, HYO: 0.286 g kg-1 and SCO: 0.126 g kg-1, were achieved in plants treated with NT at 80 and 20 mg l-1, respectively. The maximum and minimum plant biomass and subsequently total alkaloids yield were obtained in plants exposed to NT at 40 mg l-1 and controls, respectively. Our results suggest that NT in appropriate level (40 mg l-1) may act as an elicitor for biochemical responses and tropane alkaloids biosynthesis in H. niger plants.