Sensory and Physicochemical Properties of Sweet Potato Chips Made by Vacuum-Belt Drying.

Sweet potato chips were produced by vacuum-belt drying and compared to deep-fat fried ( DFF) chips. Two thicknesses (0.8 and 1.5 mm) and four drying temperatures (100, 120, 140 C and mixed temperature [ T-mix] = 100/120/140 C) were investigated. Vacuum-belt dried ( VBD) chips exhibited a similar texture to those DFF while maintaining their natural color and β-carotene content. T-mix chips were found to have the greatest likability. VBD products prepared at the lower temperatures maintained L* C* h values closest to unprocessed sweet potatoes. Environmental scanning electron microscopy micrographs demonstrated that T-mix chips possessed the most uniform cell structure. VBD chips prepared at the T-mix conditions, along with DFF chips, had the lowest degree of hardness but exhibited high fracturability. The former gave a hardness of 504.7 g force with 7.75 fracture peaks, while the latter had a hardness of 500.6 g force and 9.25 fracture peaks. VBD chips manufactured at the lower temperatures retained 55.5 to 65.9% of the sweet potato's β-carotene content, while those prepared at 140 C or by frying retained only 33.1 to 34.2%. Practical Applications Sweet potatoes are a major world food crop, and a valuable source of carotenoids, vitamin C and dietary fiber. Drying and other thermal processes have been employed to preserve sweet potatoes and to convert them into an ingredient form that is convenient for use in food products. Furthermore, there has been a rising demand for low-fat, healthy fruit- and vegetable-based snack items. This study examines the applicability of relatively low-temperature vacuum drying as a process to remove water without substantially altering the vegetable's phytonutrients, yet, can create a structure that produces crispness. Vacuum-belt drying at 100-120 C, or at a specific temperature combination, can yield sweet potato chips that are crisp, have good color, retain a marked quantity of β-carotene and are well-liked by consumers. [ABSTRACT FROM AUTHOR]