Faculty Publications
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Item An Insight into the Gelatinization Properties Influencing the Modified Starches Used in Food Industry: A review(Springer, 2022) Chakraborty, I.; N, P.; Mal, S.S.; Paul, U.C.; Rahman, M.H.; Mazumder, N.Native starch is subjected to various forms of modification to improve its structural, mechanical, and thermal properties for wider applications in the food industry. Physical, chemical, and dual modifications have a substantial effect on the gelatinization properties of starch. Consequently, this review explores and compares the different methods of starch modification applicable in the food industry and their effect on the gelatinization properties such as onset temperature (To), peak gelatinization temperature (Tp), end set temperature (Tc), and gelatinization enthalpy (ΔH), studied using differential scanning calorimetry (DSC). Chemical modifications including acetylation and acid hydrolysis decrease the gelatinization temperature of starch whereas cross-linking and oxidation result in increased gelatinization temperatures. Common physical modifications such as heat moisture treatment and annealing also increase the gelatinization temperature. The gelatinization properties of modified starch can be applied for the improvement of food products such as ready-to-eat, easily heated or frozen food, or food products with longer shelf life. © 2022, The Author(s).Item Investigation of structural and physico-chemical properties of rice starch with varied amylose content: A combined microscopy, spectroscopy, and thermal study(Elsevier B.V., 2022) Govindaraju, I.; Zhuo, G.-Y.; Chakraborty, I.; Melanthota, S.K.; Mal, S.; Sarmah, B.; Baruah, V.J.; Mahato, K.K.; Mazumder, N.Starch from a given botanical source can vary considerably in terms of physicochemical properties in its native and hydrolyzed forms. The current study investigated the structural and functional characteristics of starch from ten indigenous rice varieties endemic to Northeast India. In vitro enzymatic hydrolysis was used to reveal the dextrose equivalent profile of each type of starch. Gezep Sali and Betguti Sali respectively exhibited the highest and lowest starch hydrolysis. Among the ten rice varieties, amylose content varied between 7.50 and 28.58%. Optical and scanning electron microscopy (SEM) revealed the polyhedral shape of the native starch granules and deformation of the shape upon enzymatic hydrolysis. Second harmonic generation (SHG) microscopy and X-ray diffraction (XRD) analysis confirmed the presence of and variations in starch crystallinity. XRD revealed spectral peaks characteristic of A-type starch crystals in the native form. The elevated intensity of XRD peaks in hydrolyzed starch granules confirmed the occurrence of amylose hydrolysis rather than hydrolysis in amylopectin regions. Fourier transform infrared (FTIR) spectra revealed the common stretching and bending of bonds in all native starches; however, changes were observed in the fingerprint region (1080, 1000, 926 cm−1) of hydrolyzed starch granules, which indicates the amylolysis of the amylose region and disturbances in the ordered arrangement in the crystalline part. Differential scanning calorimeter (DSC) endotherms revealed the highest and lowest gelatinization peak temperatures in Harfoni (78 °C) and Tulosi Sali (41 °C) rice cultivars, respectively. The findings in this study can help to optimize the usage of rice starch in food and non-food industries. Furthermore, understanding the control points of starch digestion and genetically tailoring rice grains with different digestibility could be beneficial for nutraceutical applications. © 2021 Elsevier LtdItem Investigation of physico-chemical properties of native and gamma irradiated starches(Elsevier Ltd, 2022) Govindaraju, I.; Sunder, M.; Chakraborty, I.; Mumbrekar, K.D.; Mal, S.; Mazumder, N.Starch is one of the most abundantly found carbohydrates in cereals, roots, legumes and fruits located in amyloplasts of plants. Native starch comprises of amylose, a linear α-glucan with α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. In food industries, the native starch is modified to manufacture the desired quality of starchy foods by means of physical, chemical, and enzymatic modification techniques. Gamma irradiation technique is one among the physical modifications of starch which is extensively used for the modification of native starch as it is rapid, less toxic and cost-effective technique. When starch is radiated with gamma rays, it is observed to produce free radicals owing to cleavage of amylopectin branches and exhibit variation in their physicochemical properties. In this study, commercially available corn, rice, and potato starch were irradiated with 10 kGy dose of gamma radiation and changes in their physicochemical properties were investigated. Native and irradiated starch was subjected to enzymatic hydrolysis with bacterial α-amylase (150 U/mL). The highest starch hydrolysis was observed for irradiated rice starch (17.03%). Amylose content of irradiated starch decreased by 3–4 %. The optical microscopic images showed the surface erosions of the irradiated starch and differential scanning calorimeter (DSC) revealed the thermal transition temperatures. Overall, starch hydrolysis and amylose content showed inverse correlation between them. Further studies regarding the effect of storage on gamma irradiated starch can help to gain new insights into the usage of modified starches in the manufacture of processed foods. © 2022Item Synthesis and detailed characterization of sustainable starch-based bioplastic(John Wiley and Sons Inc, 2022) Chakraborty, I.; Pooja, N.; Banik, S.; Govindaraju, I.; Das, K.; Mal, S.S.; Zhuo, G.-Y.; Rather, M.A.; Mandal, M.; Neog, A.; Biswas, R.; Managuli, V.; Datta, A.; Mahato, K.K.; Mazumder, N.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. © 2022 Wiley Periodicals LLC.Item Evaluation of physicochemical properties of citric acid crosslinked starch elastomers reinforced with silicon dioxide(Royal Society of Chemistry, 2024) Pooja, N.; Chakraborty, I.; Mal, S.S.; Bharath Prasad, A.S.; Mahato, K.K.; Mazumder, N.Thermoplastic starch (TPS), derived from renewable resources, offers advantages such as biodegradability and lower production costs compared to petroleum-based plastics. However, its limited mechanical properties pose a challenge for broader applications. This research aims to explore the potential of enhancing the mechanical and barrier properties of TPS films through the incorporation of silicon dioxide as a reinforcement filler and citric acid as a crosslinking agent. By introducing silicon dioxide as a reinforcement filler, the mechanical strength of the TPS films is expected to be improved. Additionally, the incorporation of citric acid as a crosslinking agent is anticipated to enhance the barrier properties of the films. The combination of these additives holds promise for creating TPS films with improved performance, contributing to the development of sustainable and environmentally friendly materials in various industries. The results reveal that SiO2 improves the stiffness of the films at lower concentrations but causes brittleness at higher concentrations. In contrast, citric acid crosslinked films exhibit improved flexibility and density. Scanning electron microscopy demonstrates the morphological changes in the films, with SiO2 affecting surface roughness and aggregate formation. SiO2 reduces film thickness and transparency, while citric acid enhances water resistance and barrier properties. X-ray diffraction analysis shows a reduction in crystallinity due to the plasticization process. Fourier-transform infrared spectroscopy highlights chemical changes and antimicrobial activity is observed with citric acid against specific bacteria. The soil burial test reveals that citric acid crosslinked films exhibit slower degradation due to antimicrobial properties. The combination of SiO2 reinforcement and citric acid crosslinking enhances the overall performance of the films, promising sustainable and environmentally friendly materials for various applications. © 2024 The Royal Society of Chemistry.Item Investigation of the physicochemical factors affecting the in vitro digestion and glycemic indices of indigenous indica rice cultivars(Nature Research, 2025) Govindaraju, I.; Das, A.R.; Chakraborty, I.; Mal, S.S.; Sarmah, B.; Baruah, V.J.; Mazumder, N.Rice (Oryza sativa) is a vital food crop and staple diet for most of the world’s population. Poor dietary choices have had a significant role in the development of type-2 diabetes in the population that relies on rice and rice-starch-based foods. Hence, our study investigated the in vitro digestion and glycemic indices of certain indigenous rice cultivars and the factors influencing these indices. Cooking properties of rice cultivars were estimated. Further, biochemical investgations such as amylose content, resistant starch content were estimated using iodine-blue complex method and megazyme kit respectively. The in vitro glycemic index was estimated using GOPOD method. The rice cultivars considered in our study were classified into low-, intermediate-, and high-amylose rice varieties. The rice cultivars were subjected to physicochemical characterization by using Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) techniques. FTIR spectral analysis revealed prominent bands at 3550-3200, 2927-2935, 1628-1650, 1420-1330, and 1300-1000 cm?1, which correspond to –OH groups, C=O, C=C, and C–OH stretches, and H–O–H and –CH bending vibrations, confirming the presence of starch, proteins, and lipids. Additionally, the FTIR ratio R(1047/1022) confirmed the ordered structure of the amylopectin. DSC analysis revealed variations in the gelatinization parameters, which signifies variations in the fine amylopectin structures and the degree of branching inside the starch granules. The percentage of resistant starch (RS) ranged from 0.50–2.6%. The swelling power (SP) of the rice flour ranged between 4.1 and 24.85 g/g. Furthermore, most of the rice cultivars are classified as having a high glycemic index (GI) based on the estimated in vitro GI (eGI), which varies from 73.74–90.88. The cooking properties of these materials were also investigated. Because the amylose content is one of the key factors for determining the cooking, eating, and digestibility properties of rice, we investigated the relationships between the amylose content and other biochemical characteristics of rice cultivars. The SP and GI were negatively correlated with the amylose content, whereas the RS had a positive relationship. The findings of our study can be beneficial in illustrating the nutritional profile and factors affecting the digestibility of traditional rice cultivars which will promote their consumption, cultivation, and contributes to future food security. © The Author(s) 2025.