Joan M. King

Summary Six prevalent sweet potato cultivars, New Orleans, Beauregard, Japanese, Hannah, Garnet and Jewel, were selected to determine the distribution of terpenes in their flesh and peel. Free‐form terpenes were not detected in both flesh and peel in all the cultivars by using a solid phase microextraction (SPME) and gas chromatography–mass spectrometer (GC–MS) method. Major terpenes in the sweet potatoes were linalool and α‐terpineol and existed in bound form in flesh and peel. They were released as free‐form and determined after acid hydrolysis treatment. However, ultrasonication‐assisted acid hydrolysis decreased the levels of terpenes with increased treatment time because the broken‐down free‐form terpenes were volatile and rapidly evaporated or oxidised. For the selected cultivars, the Garnet, Jewel and Japanese cultivars had the greatest levels of linalool, while the Beauregard and New Orleans cultivars had the greatest level of α‐terpineol. Also, the concentration of linalool or α‐terpineol in the peel of each cultivar was approximately two times greater than in its flesh. This study revealed the bound form terpenes and their distribution in sweet potatoes. The results explored the potential utilisation of sweet potato peel as a natural source of terpenes.

Gluten‐free blends utilize starches, gums, hydrocolloids, and proteins for viscoelasticity, gas holding ability, and crumb structure of dough and batter without gluten. This study examines Frontière brown rice flour (HPBRF), a new high protein rice cultivar, with tapioca starch (TS) and potato starch (PS) in an aqueous model system in a mixture design, to study interaction effects on pasting properties. The effect of the flour from this new cultivar on the pasting properties of other starches typically used in gluten‐free products has not yet been tested. Pasting properties are analyzed with a Rapid Visco Analyzer (RVA). Rheological and thermal characterization of the flour and starches are also done using differential scanning calorimetry (DSC) and a rheometer. The blends of HPBRF and PS affect the pasting properties compared to each alone, and it is observed that the application of HPBRF with PS decreases breakdown viscosity and peak viscosity, significantly compared to PS alone. Also, the ternary mixture considerably decreases the retrogradation potential for HPBRF, which indicates more stability during storage. These positive and negative effects can indicate how combined usage of these ingredients for the development of bakery products can impact physiochemical properties of gluten‐free bakery products.