Faculty Publications
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Item Microscopic and spectroscopic characterization of rice and corn starch(Wiley-Liss Inc., 2020) Govindaraju, I.; Pallen, S.; Umashankar, S.; Mal, S.S.; Kaniyala Melanthota, S.; Mahato, D.R.; Zhuo, G.-Y.; Mahato, K.K.; Mazumder, N.Starch granules from rice and corn were isolated, and their molecular mechanism on interaction with ?-amylase was characterized through biochemical test, microscopic imaging, and spectroscopic measurements. The micro-scale structure of starch granules were observed under an optical microscope and their average size was in the range 1–100 ?m. The surface topological structures of starch with micro-holes due to the effect of ?- amylase were also visualized under scanning electron microscope. The crystallinity was confirmed by X-ray diffraction patterns as well as second-harmonic generation microscopy. The change in chemical bonds before and after hydrolysis of the starch granules by ?- amylase was determined by Fourier transform infrared spectroscopy. Combination of microscopy and spectroscopy techniques relates structural and chemical features that explain starch enzymatic hydrolysis which will provide a valid basis for future studies in food science and insights into the energy transformation dynamics. © 2020 Wiley Periodicals, Inc.Item Revealing the Structural Organization of Gamma-irradiated Starch Granules Using Polarization-resolved Second Harmonic Generation Microscopy(Oxford University Press, 2023) Chen, M.-C.; Govindaraju, I.; Wang, W.-H.; Chen, W.-L.; Mumbrekar, K.D.; Mal, S.S.; Sarmah, B.; Baruah, V.J.; Srisungsitthisunti, P.; Karunakara, N.; Mazumder, N.; Zhuo, G.-Y.Starch is a semi-crystalline macromolecule with the presence of amorphous and crystalline components. The amorphous amylose and crystalline amylopectin regions in starch granules are susceptible to certain physical modifications, such as gamma irradiation. Polarization-resolved second harmonic generation (P-SHG) microscopy in conjunction with SHG-circular dichroism (CD) was used to assess the three-dimensional molecular order and inherent chirality of starch granules and their reaction to different dosages of gamma irradiation. For the first time, the relationship between starch achirality (χ21/χ16 and χ22/χ16) and chirality (χ14/χ16) determining susceptibility tensor ratios has been elucidated. The results showed that changes in the structure and orientation of long-chain amylopectin were supported by the decrease in the SHG anisotropy factor and the χ22/χ16 ratio. Furthermore, SHG-CD illustrated the molecular tilt angle by revealing the arrangement of amylopectin molecules pointing either upward or downward owing to molecular polarity. © 2023 Cambridge University Press. All rights reserved.Item Assessment of biocompatibility for citric acid crosslinked starch elastomeric films in cell culture applications(Nature Research, 2025) Pooja, N.; Ahmed, N.Y.; Mal, S.S.; Bharath, P.A.S.; Zhuo, G.-Y.; Noothalapati, H.; Managuli, V.; Mazumder, N.This study investigates the synthesis of potato starch elastomers reinforced with silicon dioxide (SiO2) and citric acid as a crosslinking agent to enhance their mechanical and barrier properties. Surface morphology analysis using optical microscopy revealed that pure potato starch films had uneven surfaces. However, higher SiO2 concentrations increased roughness, while citric acid crosslinked films displayed smoother surfaces overall. Water vapor transmission rates (WVTR) indicated that native starch films were highly hydrophilic, while SiO2 incorporation and citric acid crosslinking significantly reduced WVTR of 17% (30% lower than native film), enhancing the barrier properties. Tensile strength testing revealed that citric acid crosslinking increased the tensile strength by 25%, while SiO2 further reinforced the films but decreased elasticity by 15%. SiO2 had little impact on degradation rates, while citric acid crosslinking delayed microbial growth, extending film longevity by 20%. Biocompatibility assays using SiHa, HT-29, and HEK 293 cell lines revealed that the films had varying degrees of cell confluency. Films with both SiO2 and citric acid showed improved confluency (20% higher) compared to films containing only SiO2. However, citric acid alone resulted in the highest confluency (95% viability), suggesting its significant role in biocompatibility. This eco-friendly approach demonstrates substantial advancements in film properties, offering potential applications in diverse biomedical industries. © The Author(s) 2025.