Question

While testing the presence of starch in potato, why cannot we see the starch granules under the microscope?​

Answer 1

Answer:

Tribology of swollen starch granule suspensions from maize and potato.

Answer 2

1. Measurement of starch granules by light-microscope is the preferred approach in most laboratories because it is simple, rapid and visu-al and because both size and shape can be inves-tigated. However, juice from potato tubers con-sists of starch granules of very different sizes and precipitation/movement speeds which can cause artefacts when sampling the juice and recording microscopic images. In the previously described method, a razor blade was used to scrape and transfer juice from potato tubers directly to a drop of water on a slide for micro-scopic observation. In this study we used cham-bers made from tape on microscopic slides to reduce the cover-slip-induced shifting of small and medium granules. We improved the starch measurement reproducibility by testing various juice sampling methods. The reproducibility between repeated experiments using 10 culti-vars was increased from a correlation coefficient r=0.815 in the razor-blade-scraping method to r=0.923 in a squeezing-juice method. The largest starch granule detected was 151 µm in length. Sampling methods (using a razor-blade or a garlic press) strongly influenced the granule length values measured from the same potato tuber. The results indicated that 1) The squeez-ing-juice approach is more reproducible, and 2) The average length of starch granules is one of the most reproducible scores but varies accord-ing to juice-sampling methods.