Transfer of heat and moisture during microwave baking of potatoes

Abstract

Microwave baking of potatoes comprised two phases. In the ®rst phase the internal temperature of the potatoes rose to approximately 100°C with little loss of water vapour. The uniformity of internal heating during this phase was assessed by identifying gelatinised starch. Starch gelatinisation began near the outer surface after 1.5 min of cooking and was complete by 2.5 min. During the second cooking phase the thermal energy absorbed was used to evaporate water. When immersion in boiling water was substituted for this second phase of microwave cooking, it took signi®cantly longer for the internal texture to soften adequately for the potatoes to be considered cooked. This suggests that microwave cooking in¯uences texture independently of the thermal pro®le of the cooking process. Damage by escaping steam is suggested as a mechanism.

In vitro Starch Digestibility and Predicted Glycemic Index of Microwaved and Conventionally Baked Pound Cake

“…RS in fresh microwave-baked pound cake crumbs was 4.4% and differed significantly (P≤0.05) from that in conventionally baked pound cake (3.6%; Table 2). Differences in RS content are likely attributable to the fact that microwave heating generates a fast input of microwave energy into the center of the product, thereby producing substantial evaporative water loss that has no equivalent in any other form of cooking [30]. Although the required temperature is achieved, gelatinization does not occur completely in microwave-heated samples due to limited starch-water interaction during the short microwave heating period [17].…”

Dielectric properties of deformed early potatoes

“…The electromagnetic waves are used frequently in many disciplines of food science and food technology. At present, the most frequent is the use of the microwave heating for cooking and baking of food products (Wilson et al 2002;Vollmer 2004). The main advantage of the microwave cooking consists in quickness of the whole operation because the cooking proceeds continuously in the whole volume of the approximately homogeneous body cooked.…”

Potato tuber permittivity during deformation in compression

“…On the present, the most frequent is use of the microwave heating for cooking and baking of food products (Vollmer 2004;Wilson et al 2002). The main advantage of the microwave cooking consists in quickness of the whole operation because the cooking proceeds continuously in the whole volume of the approximately homogeneous cooked body.…”

“…The sources of the inhomogeneous heating consist mainly in inhomogeneous structure of the heated product. The microwave heating is well defined physically (Vollmer 2004) and depends on the proper dielectric properties of the heated body and on the character of the microwave used (Wilson et al 2002).…”