Arashdeep SinghGeetanjali2024-03-042024-03-042023Geetanjali (2023). Modification of corn and rice starches: optimization and utilization as functional ingredients (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810207330The study was conducted to observe the effect of ultrasonication on native corn and rice starch and their utilisation as functional ingredient in preparation of food products. Both native corn and rice starches were subjected to ultrasonication using Probe Sonicator for 30 minutes at 40% amplitude, 20 kHz frequency. Followed by spray drying using a spray dryer set to an input temperature of 160 °C, an air pressure of 2 bar, and a feed pump rate of 16 rpm. Native and ultrasonicated corn and rice starches were assessed for physical characteristics, functional properties, color characteristics , FT-IR and X-Ray Diffraction. Ultrasonicated corn starch was further incorporated at 0-25% level as a fat replacer for the preparation of muffins and 0-5% level for curd as functional ingredient. Muffin batter prepared using ultrasonicated corn starch at 0-25% was assessed for rheology. Prepared muffins were further assessed for physical properties such as weight showed significant (p<0.05) increase whereas height, bake loss, volume and specific volume showed decrease in values with the addition of ultrasonicated corn starch. Proximate composition includes moisture, ash, protein, fibre and energy showed insignificant increase in values whereas fat content decreased significantly (p<0.05) with increasing level of ultrasonicated corn starch. Rheology and viscosity of curd were analysed. Physicochemical properties of curd such as syneresis, pH, fat showed non-significant decrease in values with addition of ultrasonicated corn starch while increase in acidity, moisture, total solids and ash content was observed. Muffins and curd were also assessed for textural characteristics, color characteristics, FT-IR spectra and sensory evaluation. The FT-IR spectra of muffins revealed the existence of ultrasonicated maize starch in muffins, as seen by peaks seen in the 950–1150 cm-1 range. Additionally, aliphatic fat groups were detected, as indicated by vibrational disruptions visible at peaks 2849 and 2918 cm-1. FT-IR spectra of curd showed the prominent peaks in the wavelength range 1000- 1200 cm-1 due to the presence of C-O-C linkages and further peaks at 1650 and 1750 cm-1 due to the presence of C=O linkages of fatty acids. Lactose also exhibited vibrations in spectra in the range 2900-3200 cm-1. Control and best selected ultrasonicated corn starch containing curd sample among all were studied for changes in syneresis, acidity, pH, LAB count and overall acceptability during their storage. LAB count was noted to be decreased during 7 days storage period, the overall acceptability of control curd and decreased while the best selected curd with ultrasonicated corn starch kept the desirable quality throughout storage period.EnglishThesis