Microstructural changes of starch in cooked wheat grains as affected by cooking temperatures and times
| Autor: | Robert W. Hosken, John F. Ashton, John Furst, Khongsak Srikaeo |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
Materials science Scanning electron microscope Starch Wheat flour food and beverages Mineralogy Cooker Microstructure Polysaccharide law.invention chemistry.chemical_compound Optical microscope chemistry law medicine Food science Swelling medicine.symptom Food Science |
| Zdroj: | LWT - Food Science and Technology. 39:528-533 |
| ISSN: | 0023-6438 |
| DOI: | 10.1016/j.lwt.2005.04.004 |
| Popis: | The changes of starch microstructure in soft and hard wheat grains after cooking in a pressure cooker were investigated using a scanning electron microscope (SEM) and a light microscope (LM) in conjunction with image analysis. The conditions studied included variation of the cooking times (20–120 min) at the constant temperature (120 °C) and with variable temperatures (110–140 °C) for constant time (40 min). SEM images showed that steam induced changes in the intact starch granules of cooked wheat grains, with the microstructure becoming more in mud-like structure, with increased cooking time or temperature. The swelling and gelatinization of starch granules could contribute to this change. Suspensions of cooked wheat flour were selectively stained with iodine, for observation using the LM. The image analysis software was used for quantitative analysis of the images captured from the LM, providing both the number and area of the starch granules (determined from the dark-blue spots) per fixed image size. With increased cooking time or temperature, the number of starch granules decreased and the area increased as a result from the swelling and melting of starch granules. This study demonstrated the use of SEM and LM for the investigation of starch granules in cooked wheat grains without prior starch isolation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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