Graphical Graphical abstract of functions of biocompatible nanomaterials in food industry.

The present investigation studied the physicochemical, mechanical, structural, thermal, and morphological attributes of a novel edible film formed from fenugreek protein concentrate. Films were produced at different pH—9, 10, 11, and 12—and the effect of the pH on the films was studied. As the pH increased, tensile strength increased while water vapor absorption decreased, which is interrelated to the surface morphological properties; as the pH increased, the surface became smoother and compact without any cavities. The films produced were darker in color. Fenugreek protein films exhibited good thermal stability. Fourier transform infrared spectroscopy (FTIR) revealed the presence of strong bonding for the films made at alkaline pH. X-ray diffraction analysis (XRD) indicated the major structure of the film was amorphous. The study demonstrated that the fenugreek protein concentrate film has influential characteristics and can be used as an edible packaging film.

Starch, a polymeric carbohydrate widely present in plant biomass, has gained popularity owing to its functional characteristics, lower cost and ability to completely decompose without any toxic byproducts. Native starches have the fewest applications among the food and non-food sectors. Thus, modifications to eliminate their shortcomings, viz., low pH, reduced viscosity, easy retrogradation, gelling, and syneresis during cooking, will prove to be useful through application extension. Physical modifications are simple and less expensive. Meanwhile, chemical modifications involve the extraction of the hydroxyl group from the starch molecule, yielding the desirable outcome for the extensive use of starch. With the advent of green chemistry, considerable attention has been paid to the development of novel physical modifications with the advantages of high efficiency, environmentally friendly operation, and ease of starch modification. High hydrostatic pressure (HHP) processing, microwave processing, pulsed electric field (PEF), and cold plasma are some of the tactics that govern this modification accordingly, keeping in mind the environment suitability and application broadness as well. Recently, there has been increasing interest in the chemical alteration of starches by means of oxidation, succinylation and acetylation to explore new horizons to improve their utilization potential beyond food, viz., pharmaceuticals, textiles and other fields. Increases in the solubility features, in vitro digestibility terms, resistant starches proportion and application extension are the selected traits discussed herein.

Fenugreek (Trigonella foenum graecum) is an annual plant belonging to the family Leguminosae or Fabaceae. The seeds of fenugreek contain 26.8% soluble fiber chemically identified as galactomannans with properties similar to soluble fiber of guar seeds and psyllium husk and so on. Galactomannans are biopolymers consisting of linear core poly (1,4)‐β‐D‐mannan backbone having varying degrees of D‐galactosyl substituents attached by 1,6‐glycosidic linkages. Different galactomannans derived from various legumes usually differ in molecular weight, ratio of mannose to galactose, and the mode and place of linkages of galactose moieties to the mannan backbone. Fenugreek gum has a galactose to mannose ratio of 1:1, showing the highest amount of galactose resulting in its highest water solubility compared with guar and locust bean gum. It suggested that the galactose and mannose moieties are linked uniformly in fenugreek gum resulting in maximum hydration and solubility. This M/G ratio affects the physicochemical properties of galactomannans and is inversely related to the solubility of gum. Galactomannans sterically stabilize the emulsions against flocculation and coalescence by getting adsorbed onto oil droplets. In addition to this, galactomannans are all found to exhibit some surface, interfacial, and emulsification activities. Because of these properties, it is preferred over other natural hydrocolloids as an excellent ingredient for various food applications. As a hydrocolloid, fenugreek gum provides texture, appeal, gelling, thickening, emulsifying, stabilizing, and encapsulating properties. In the present review, we summarized the extraction, purification, chemical, functional properties, molecular structure, thermal and rheological behavior of gum isolated from fenugreek seeds, and then vital application of this traditional source of hydrocolloids in food, pharmaceutical, and other industries.