PRODUCTION OF TORTILLA CHIPS FROM CORN ANDIOR SORGHUM: ~~ II.EVALUATION OF STARCH GELATINIZATION AND CRYSTALLINITY | ||||
| Journal of Food and Dairy Sciences | ||||
| Article 4, Volume 29, Issue 12, December 2004, Page 7117-7136 PDF (4.77 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jfds.2004.240592 | ||||
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| Authors | ||||
| A. Shalaby1; Nefisa Hegazy1; Somaya Abd EI-Moneim2; F. Salem2; A. M. Hussein1 | ||||
| 1Food Sci. and Tech. Dept., National Res. Centre, Dokki, Cairo | ||||
| 2Food Sci. Dept., Fac. Agric., Zagazig Univ., Zagazig, Egypt. | ||||
| Abstract | ||||
| Tortilla chips are made from corn and sorghum by nixtamalization process. Nixtamalization caused some changes in physical apperaence of the protein and starch of the kernel. Gelatinization and crystallinity are of cardinal importance in starch technology. So, this study was performed to follow-up the degree of starch gelatinization (loss of birefringence and structure disruption) and the changes in starch crystallinity during tortilla chips processing. Starch granules in raw grains appeared as distorted spherocrystals, with a typical dark cross. The majority of starch granules in nixtamalized samples were swollen, adhered to other granules and exhibited partial birefringence. Masa had irregular in shape and often the external part of the granules exhibted birefringence. Tortilla chips lost about 95% of birefringence. The structural changes as evaluated by scanning electronic microscope revealed that raw samples had a mixture of round granules from the floury endosperm and angular granules from the horny endosperm. Starches granules are disrupted and swollen by cooking. Masa had irregular and swollen starch granules and a cohesive, glue like structure was appeared. Misshape starch granules along with more uniform, smoothes and more amorphous appearance of starch granules were appeared in tortilla and tortilla chips samples. The X- ray diffractograms of raw samples show pattern closely to A-type cereal straches. A diffraction peak of a feature of V-type starch was appeared in the nixtamal samples. Masa samples had the main peaks of A-type starch along with developing a diffraction peaks feature of V-patterns of starch. Starch was changed from a crystalline to an amorphous state as a result of baking and frying. | ||||
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