Glass transition temperature
The addition of carriers significantly increased the glass transition
temperature (Tg) of spray-dried purple sweet potato flours.
The Tg values of spray-dried flours increased in the carrier order of
MD (55.05 C)>MD/b-CD (54.70 C)>b-CD (54.30 C)>none
(51.53 C). The Tg values of flours with carriers were not dramatically
differed from that of MD and b-CD. The increases in Tg values
of flours with various carriers possibly due to the addition of
carriers (Ahmed, Akter, & Eun, 2010) and the lower moisture
content of carrier-incorporated flours (Goula & Adamopoulos,
2008) (Table 1). Goula and Adamopoulos, (2010) proposed that
the value of Tg was partly dependent on the moisture content of
flour with the higher the moisture content the lower the Tg.