Title of project: Development of assay for testing protein quality in maize
Project funding: Institute
Total approved cost of the project: NA

Objective:

• To develop an accurate, reliable and short laboratory protocol for quantitative determination of lysine and tryptophan contents in maize cultivars.
• To develop an easy, user-friendly on-site protocol for qualitative and semi-quantitative determination of protein quality in maize.
• To test the accuracy of the two methods with respect to skill of operator, time consumed and shelf-life of test components.

Project team: Dr. Alla Singh and Dr. Dharam Paul
Major achievements: –
1. A formulation designed, which is capable of hydrolyzing maize protein in half an hour. This formulation is compatible with Reagent C (ferric chloride in acetic acid) used in Hernandez and Bates (1969) protocol for estimating tryptophan.

Figure 1: Demonstration of maize endosperm protein hydrolysis and colour development for tryptophan estimation through ‘proprietary formulation’ developed at IIMR. (a) A: Protein markers with size shown in kDa; B: Crude protein isolated from maize endosperm; C: Maize endosperm sample treated with ‘proprietary formulation’ for 30 minutes. (b) Colour development for estimating tryptophan released after hydrolysis of proteins. The four tubes shown contain (from left to right): 0 mg, 100 mg, 200 mg & 300 mg of starting maize endosperm sample, hydrolyzed through the new method using ‘proprietary formulation’.

2. Identified factors that interfere with assay, which include nature of polypropylene tubes, quality of grinding and source of acetic acid.
3. Refinement in the test assays has been proposed. The shelf-life of components is short and need fresh preparation for quantification.