Title - Tender Specification for the - Differential Scanning Calorimeter (DSC) for Food Analysis

Tender Reference Number: TDU/Tender/2026-2027/51

Deadline for Submission: 8th November 2026 at 04:00 PM

Name & Technical Specification:

TECHNICAL SPECIFICATION-Differential Scanning Calorimeter (DSC) for Food Analysis

1. Purpose and Scope

This document specifies the technical requirements for a heat-flux differential scanning calorimeter (DSC) to be installed in the food analysis laboratory at TDU. The instrument is intended to characterise the thermal behaviour of three principal food components — proteins, starches, and fats/oils — with the following core objectives:

• Quantify the degree of protein denaturation (denaturation temperature and residual denaturation enthalpy).

• Characterise starch gelatinisation (onset, peak and end temperatures, and gelatinisation enthalpy), and related retrogradation and amylose–lipid complex transitions.

• Study fats and oils: melting and crystallisation profiles, solid-fat content, polymorphic behaviour, and oxidative stability (oxidation onset temperature / induction time).

2. Key Technical Considerations Before Purchase

The following factors should be assessed and confirmed by every bidder. They are the points on which food DSC performance most often succeeds or fails.

• Measuring principle — heat flux vs power compensation. Heat-flux (single furnace) instruments, in which sample and reference sit on separate sensors within one furnace, are the mainstream choice and comfortably cover food applications. Power-compensation (double-furnace) instruments give the fastest response and best separation of close-lying peaks, which can help with fat polymorphism, but at higher cost. For this laboratory, heat-flux is sufficient and cost-effective; bidders should state their principle clearly.

• Temperature range and cooling. Oils crystallise between −60 and −80 °C, so a cooling facility reaching at least −80 °C without liquid nitrogen is the practical minimum. Liquid-nitrogen cooling (to ≈−150 °C) is a useful option; the upper limit should comfortably be 400 °C for oxidation-onset work.

• Sensitivity and resolution. Starch and protein transitions are weak (a few J/g) and fat melting produces multiple overlapping peaks. The instrument therefore needs high sensitivity (0.1 µW) to detect weak events and high resolution to separate close-lying ones. Both must be quoted with the basis of measurement.

• Baseline stability and flatness. A flat, repeatable baseline is essential to integrate weak endotherms accurately and to detect small glass transitions. Look for baseline repeatability and baseline stability/curvature figures over the relevant range.

• Temperature accuracy and precision. Determines the reliability of onset/peak temperatures. Precision (repeatability) is as important as accuracy for QC use; both should be quoted from repeated indium runs.

• Calorimetric (enthalpy) accuracy and precision. Directly governs the accuracy of ΔH, and therefore of the calculated degree of denaturation and gelatinisation enthalpy. Insist on values derived from ten consecutive indium runs.

• Heating and cooling rates. A wide, programmable range (e.g. 0.01–100 °C/min or better) supports kinetic studies and method transfer. High cooling rates improve throughput.

• Sensor and furnace construction. A multi-thermocouple thermopile sensor (typically 50–120 thermocouples) with a chemically resistant surface (ceramic or gold-coated) is preferred. A corrosion-resistant furnace (silver/silver-alloy or platinum-alloy) ensures durability and cleanliness, especially under oxygen.

• Gas control. Integrated mass-flow controllers for method and protective gases, plus software-controlled automatic gas switching between inert (N₂) and reactive (O₂) atmospheres, are required for oxidative-stability testing. An eco/idle mode to shut off gas when idle reduces running cost.

• Crucibles and sample sealing. The crucible range matters as much as the instrument. The purchase must include a hermetic sealing press, aluminium open and hermetic pans, large-volume sealed/high-pressure crucibles for starch slurries, pre-pierced lids for oxidation studies, and a sapphire disc for heat-capacity calibration.

• Automation and upgradability. The system should be modular and upgradable to an autosampler (typically 34–70 positions) later, so that routine throughput can be increased without replacing the instrument.

• Software and data analysis. Software must run on a current Windows platform and evaluate glass transition, melting, crystallisation, onset/peak/end, enthalpy, specific heat capacity, and purity, with modulated (temperature-modulated) DSC to separate reversing from non-reversing heat flow. Quality-control features (control charts) and customisable PDF reporting are desirable; software upgrades should be provided at no extra cost.

• Standards compliance. The instrument and methods should align with relevant standards — for example ASTM D3418, E793, E794, E928, E1269, D3895, D4591 and D6604, and ISO 11357 and 19935 — and, where applicable, pharmacopoeial thermal-analysis methods.

• Service, training and warranty. On-site installation and application training, an authorised Indian service representative, a clear warranty period, and an option for an annual maintenance contract should all be confirmed.

• Infrastructure and operating environment. Pre-installation requirements (power, gases, bench space, ambient temperature), supply of a suitable PC and printer, and any requirement for a cooling unit or liquid-nitrogen dewar should be stated by the bidder.

3. Minimum Technical Specification

The following table defines the minimum acceptable performance. Bidders must state their actual values and the basis of measurement. Values shown as “better than” indicate a preference for higher performance where it is available at reasonable cost.

4. Accessories and Consumables to be Quoted

The following must be included in the offer (not quoted as unbudgeted extras):

• Hermetic crucible sealing press and sealing tools.

• Crucible handling / accessory set (tweezers, spatula, funnel, needles, cutter and cutting plate, micro-syringe, glass-fibre pen, air blower, push-rod).

• Aluminium open pans and crimp covers; aluminium hermetic (sealed) pans.

• Large-volume sealed or high-pressure crucibles (40–60 µL) for starch and protein slurries.

• Pre-pierced / pierceable lids for oxidation and autosampler use.

• Sapphire disc (and/or the manufacturer's Cp reference) for specific-heat calibration.

• Calibration standards with traceability certificates (at least three, e.g. indium, tin, zinc).

• Gas tubing, fittings and pressure regulators for purge/protective gases.

• Workstation PC and laser multifunction printer (as specified in Section 4).

• Recommended: analytical balance (0.01 mg readability) and UPS for the instrument and PC.

5. General, Commercial and Service Terms must be included

• Pre-installation requirements to be stated by the bidder (power supply, gases, bench space, ambient conditions, cooling-water or LN₂ provision).

• Instrument manual to be supplied in both hard copy and electronic form; a detailed standard operating procedure (SOP) for routine analysis to be provided.

• Authorised Indian representative: the bidder must name its authorised Indian representative with contact details, and provide a list of existing users of similar DSC/thermal-analysis installations in India with contact details.

• Installation and on-site training by a qualified installation/application engineer, covering routine analysis, method development, calibration and routine maintenance, at no extra cost.

• Warranty of at least three years, comprehensive, from the date of installation.

• Software updates/upgrades to be available at no additional cost.

• Delivery, payment terms, cancellation and service/AMC terms to be clearly stated.

• Compliance with applicable local procurement norms and after-sales support availability to be confirmed.