Ms. Nisha Pujari will present her Ph.D. Viva-voce examination as per the details below:
Date: 11th February, 2025
Time: 1100 - 1200 hrs.
Venue: Conference Room No. 1, C-TARA Office
Title: Nutritional Characterisation of Non-centrifugal Sugar: Investigating Blood Glucose Impact and Iron Uptake
Supervisor: Prof. Amit Y. Arora
Co-supervisor (External): Prof. Narendra G. Shah
External Examiner: Prof. Jayeeta Mitra (AGFE, IIT Kharagpur)
Internal Examiner: Prof. Sanjay Mahajani (Chemical Engineering)
Chairperson: Prof. Yogendra Shastri (Chemical Engineering)
Abstract:
Non-centrifugal sugar (NCS), also known as jaggery, is a sweetener manufactured by concentrating sugarcane juice. Sugars, moisture, minerals, and biologically active compounds are the main constituents of interest in NCS. Although sugarcane raw juice and NCS have been shown to offer health advantages, there are very few phytochemical research on the plant, and its bioactive components have not yet been fully understood. The main focus of this thesis was to evaluate these bioactives and verify their biological absorption and functionality. In the initial approach, a total of 30 NCS samples were evaluated for variations in their composition of minerals, vitamins and bioactive compounds, with respect to processing conditions. The micronutrient profile, total phenolic (TPC) and flavonoid content (TFC), water activity, and browning index varied between block and powder samples. Few unreported phenolics and flavonoids such as isoferulic acid, prunitrin, and maritimetin were detected in selected NCS samples which are known to have anti-inflammatory properties. Variations among in vitro antioxidant activity (DPPH EC50 = 2.5-18 mg/mL, ABTS EC50 = 0.15-0.5 mg/mL and FRAP = 8-21 μmol/g) could be correlated (r≥0.5) with phenolics (3-6 mg GAE/g NCS) and flavonoids (1-3 mg QE/g NCS) contents. Block NCS showed lower shelf-life compared to powders. It was found that, a standard composition of micronutrients and bioactives cannot be considered for NCS produced even at the same unit during the same season. Although NCS was found to constitute of a variety of minerals, it did not meet the recommended dietary allowance (RDA). Almost 70 g of NCS should be consumed in order to fulfill at least 10% of RDA. Sugarcane's source, cultivation climate, soil type, crop handling techniques, extent of juice extraction, clarification process, the type of lime utilised, heat treatment of the cane juice, and impurity removal efficiency all have a significant impact on its quality.
Another objective of this thesis was to investigate the potential health benefits NCS, by evaluating their α-glucosidase inhibitory properties and subsequent effects on blood glucose levels through clinical trials. The study also revealed the profile of the bioactive compounds in NCS that may contribute to these effects. Nine NCS samples were analyzed with refined sugar, aspartame, acarbose, and green tea to assess their α-glucosidase inhibition potential. Quantitative assessments of TPC and TFC were performed, and their correlation with α-glucosidase inhibition was evaluated. On the basis of this, a clinical trial (N = 104) was conducted to study the effect of NCS on blood glucose profile in comparison to refined sugar and glucose. Results indicated a significant inhibition of α-glucosidase by NCS, with a strong negative correlation between total polyphenolic content and the IC50 value of α-glucosidase inhibition (r = -0.958; p < 0.001). The clinical trial demonstrated a notable reduction in peak blood glucose levels for NCS, with a fold change of 0.43 and 0.53 for participants aged 18-39 and 40-60, respectively, as compared to refined sugar. Using mathematical model, it was found that consumption of refined sugar caused blood glucose profile to respond in a way similar to a pre-diabetic individual (70 % of participants) whereas NCS consumption exhibited such effect on only 15 % of the participants. Hence, the presence of certain minerals and polyphenols make NCS a good candidate as a healthier sweetener over refined sugar.