No abstract

Potatoes are highly consumed food around the world, usually following processing of some kind. Apart from its noteworthy presence in diets, potato starch has a multitude of industrial applications as a food additive and recently in novel domains such as nanotechnology and bioengineering. This review examines the microscopic and spectroscopic methods of characterizing potato starch and compares the different properties. The microscopic techniques such as optical microscopy and Scanning Electron Microscopy (SEM) allow observation of structural elements of potato starch. Differential Scanning Calorimetry (DSC) delves into the thermal behavior of starch in presence of water, while Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD) analyze the behavior of various chemical bonds and crystallinity of starch. These characterizations are important from a dietary point of view for patients requiring a low-glycemic diet, as well as in facilitating research into a wider array of industrial applications.

Starchy food items such as rice and potato with high carbohydrate content raise blood sugar. Hence, consuming low glycaemic foods is one tool to keep diabetes under control. In this study, potato and brown rice (Njavara rice) starches were subjected to hydrothermal treatments: heat moisture treatment (HMT) and annealing (ANN) to develop starch-based food products fit for consumption by diabetic patients. The effects of hydrothermal treatments on physicochemical properties and in-vitro enzymatic digestion of starch were determined. It was observed that hydrothermal treatments decreased the swelling power (SP)% and increased the water solubility (WS)% of the native starches. Native potato starch (PSN) showed a high SP of 80.33%, while annealed potato starch (PANN) and heat moisture treated potato starch (PHMT) showed SP reduced to 65.33% and 51.66%, respectively. Similarly, the SP % reduced from 64.33% in native brown rice (BRN) to 44.66% in annealed brown rice (BRANN) and 38.33% in heat moisture treated brown rice (BRHMT). WS % increased from 32.86% in PSN to 36.66% in PANN and 40.66% in PHMT. In BRN, the WS % increased from 14.0% to 14.66% in BRANN and 18.33% in BRHMT. Amylose content increased from 13.23% and 14.56% in PSN and BRN to 16.14% in PANN 17.99% in PHMT, 17.33% in BRANN, and 18.98% in BRHMT. The PSN crystallinity index reduced from 33.49 to 30.50% in PANN and 32.60% in PHMT. At 12 h of enzymatic digestion, it was found that the degree of hydrolysis (DoH) of PHMT (31.66%) and PANN (36.82%) reduced when compared to PSN (41.09%). Similarly, BRHMT exhibited the lowest DoH at 12 h compared to BRANN (29.24%) and BRN (35.48%). This study highlights the importance of hydrothermal treatments on starch in developing low glycaemic index commercial starch-based food products.

There is an urgent requirement of replacing the environmentally hazardous petroleum‐based plastics with sustainable and efficient starch‐based bioplastics. Development and detailed characterization of the biodegradable bioplastics from plant‐based polysaccharides such as starch is essential to reduce plastic pollution in the environment. In this research, bioplastics were developed from an equivalent blend of starch from two different sources namely rice and potato (1:1, w/w), crosslinked with different concentrations of citric acid (CA). The effect of CA cross‐linking of starch‐based bioplastics was investigated on its physicochemical and functional properties. The X‐ray diffraction (XRD) spectra revealed that the synthesized bioplastics were amorphous in nature with broad diffraction peaks. Further, the peak at 1716 cm−1 in Fourier transform infrared (FTIR) spectra indicated the formation of ester bonds in CA cross‐linked bioplastics. Atomic force microscopy (AFM) revealed the surface roughness of the bioplastics decreased with increasing concentration of CA. Mechanical and thermal properties of bioplastics were characterized using universal testing machine, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), respectively.

Starch is an abundant plant polysaccharide that occurs naturally and the main source of carbohydrate and fuel in the human diet. Several biochemical and physicochemical studies have been performed to understand the molecular structure of starch of which microscopy, spectroscopy, and thermal analysis are the most popular. The ultrastructure and birefringence of starch granules have been observed using optical microscopy and polarization microscopy. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) have been used for spatially resolved micro to nanostructures as well as surface topography and crystallinity in the starch granules. Fourier Transform Infrared (FTIR) spectroscopy has been utilized to elucidate the chemical composition and the changes that occur in its chemical compositions on various modifications. Differential scanning calorimetry (DSC) has also been used to study the thermal characteristics of starch. This review deals with starch characterization using optical microscopy including polarization microscopy, SEM, XRD, FTIR, and DSC to understand the structural and functional characteristics of starch subjected to different processing conditions.