Effect of cultivar, processing, and storage on the quality characteristics of sweet potato chips

This study was undertaken to compare sweet potato chips utilizing different sweet potato cultivars, and to evaluate the effect of processing and storage on the quality characteristics of the chips. Chips contained an average of 1.7% moisture, 4.6% crude protein, 52% crude fat, 1.9% ash, 4.5% total dietary fiber, and 36% carbohydrate, with an average 2411 kj/100g (155 kcal/oz.). Proximate composition of the cultivars showed no significant differences, however, total dietary fiber of the "Southern Delite" (SD) chips was significantly higher than either "W-221" (W2) or "Red Jewel" (RJ) chips. Moisture decreased with storage time and reached a plateau after three weeks. Beta-carotene content of chips averaged 2671 R.E. There was a significant difference among the cultivars in beta-carotene content with SD chips having the highest amount (3978 R.E.). Beta-carotene decreased with the presence of salt or air over storage time. Chips required an average force of 357g to break as measured with the Instron Universal Testing Machine. W2 required the highest force (379g) to break. Chip color was analyzed with the Hunter Colorimeter. L and "a" values significantly differed among the cultivars. The "a" value decreased due to atmosphere and time of storage. W2 chips were lighter than the other two cultivars and were more yellow than red with an "a":"b" ratio of 0.6 compared to 0.7 for SO and RJ. An experienced panel found a slightly detectable off-flavor after 9 weeks of storage with no difference due to processing or storage time. They rated chips very crispy with slightly pale-orange yellow to moderately dark-orange yellow in color.