Physicochemical properties of amorphous granular potato starch offer food applications.
Starch is a major food resource, but unfortunately native starch has limited applications. Amorphous granular starch (AGS), and non-crystalline granular starch (NCGS), which is gelatinized but which maintains its granular structure, are of great interest.
Many types of AGS can be produced using high pressure, but it is difficult to make amorphous granular potato starch (AGPS) because of its resistance to pressure. So, Korean scientists used ethanol heat and cross-linking heat treatments to make AGPS.
AGPS and cross-linked amorphous granular potato starch (CLAGPS) were prepared using ethanol heat and cross-linking heat treatments, respectively, and their physicochemical properties were examined. The investigators found that the AGPS and CLAGPS samples had completely different physicochemical characteristics from existing natural starch or pre-gelatinized starch, and hold potential for use in a variety of food applications.
For the ethanol heat treatment, 10 grams of native potato starch were suspended in 100 mL of 53% ethanol solution. The sample was heated at 94 C for 20 minutes. For the cross-linking heat treatment, native potato starch was cross-linked using a mixture of sodium trimetaphosphate and sodium tripolyphosphate at a ratio of 99 to 1, and then heated at 94 C for 20 minutes. After those treatments, the samples were washed with anhydrous ethanol and centrifuged at 3,000 rpm for 5 minutes. The scientists repeated the washing step three times. Then the samples were dried at 40 C for 24 hours.
Both AGPS and CLAGPS maintained granular forms, lost birefringence and showed some granule surface damage. Differential scanning calorimetry and x-ray diffraction showed that complete gelatinization had occurred in both. Moisture sorption isotherms showed that both AGPS and CLAGPS had lower equilibrium water content than native potato starch at certain relative humidities, indicating they had fewer hygroscopic characteristics.
CLAGPS had limited solubility, swelling power and pasting properties due to the internal cross-linking that had occurred. AGPS showed distinctive solubility, swelling power and pasting properties, compared to native potato starch and CLAGPS.
AGPS had relatively higher resistant starch content than gelatinized potato starch, while CLAGPS did not show an increase in resistant starch content in spite of cross-linking. AGPS and CLAGPS had distinctively different physicochemical properties than native potato starch, suggesting potential food applications, such as stabilizers or thickeners in dairy products which require thermal stability.
Further information. Moo-Yeol Baik, Department of Food Science and Biotechnology, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447 Republic of Korea; phone: +82 31 201 2623; fax: +82 31 204 8116; email: email@example.com.
Please Note: Illustration(s) are not available due to copyright restrictions.
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|Publication:||Emerging Food R&D Report|
|Date:||Jun 1, 2018|
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