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Fatty acid analysis Only minor differences in overall relative fatty acid composition were noted among four varieties of potatoes baked by microwave and conventional methods. However, the relative percent total unsaturated fatty acids were consistently lower in the microwave products as compared to conventionally baked potatoes regardless of variety. In addition, the relative percent rrans fatty acids was 2.5-4 times higher in the microwave process compared to the same varieties baked conventiohally.Since the potato is relatively low in lipid material which is present in a greater amount in the skin portion as compared to the interior tuber, entire potatoes were extracted. Approximately 600g (three potatoes) of cooked potatoes were immediately diced into 1L of boiling 80% methanol and refluxed for 10 min. This procedure was used to inactivate lipolytic enzymes that could alter fatty acid composition. It is acknowledged that this process probably resulted in the formation of methyl esters of the free fatty acid present. However, the goal was to methylate all lipid material present and this was accomplished as described below. Preliminary tests had indicated that the use of three potatoes from each lot was sufficient since relatively small standard deviations in relative fatty acid composition were noted. Upon cooling, redistilled diethyl ether was added and the mixture refluxed for 3 hr. The ether layer was separated and evaporated to dryness under a stream of nitrogen. The resulting lipid residue was methylated using commercially available boron trifluoride in methanol and the methylated product subjected to gas chromatographic analysis. Samples of raw potatoes of each variety were treated in the same manner.

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time period, one potato from each variety and baking method was randomly arranged for presentation to the sensory panel. A trained 20-member panel was asked to rank the eight potatoes (one A 20-member sensory panel composed of 14 women and 6 men ages of each variety baked conventionally and one of each baked by micro-20-35 who had previously taken a 16-wk college-level course in the wave) from best to worst on the basis of external appearance, internal sensory evaluation of food was used. For each sensory property evaluappearance, aroma and flavor. Different potatoes were randomly presented for each sensory property evaluated with each evaluation being ated, 8 potatoes, coded with 3-number random digets, which represented each of the 4 potato varieties baked by the 2 methods were repeated three times. Statistical evaluation of the pooled data revealed that an experimental variety was significantly superior in randomly presented and the panel asked to rank the 8 potatoes from external appearance, odor and flavor for both baking procedures. the most acceptable to the least acceptable. All evaluations were done 5Among the other varieties, conventionally baked potatoes ranked ahead min after their respective baking times which were arranged to be comof the corresponding microwaved potato. pleted at the same time. Each sensory property was judged separately, used a new set of potatoes, and was repeated 3 times.

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‘Russet Burbank’ seed potatoes, 4 to 6 oz. in weight, were stored at 0° and 5°C in various levels of O2 and CO2. Periodically during the storage season samples were removed for observation of sprouting behavior, bud and parenchyma tissue respiration measurements and determination of the rate of leakage of electrolytes from tissue sections. The performance of the remaining seed potatoes at the end of storage was evaluated in randomized complete block field trials. The degree of CO2 toxicity was increased by decreasing the O2 concentrations and the temperature of the storage environment. Occasionally a reduction in performance with increases in storage CO2 occurred but more frequently an abrupt drop from good performance to failure resulted. Incipient toxicity during the storage season could occasionally be detected by an increase in the rate of CO2 evolution from potato buds and increase in electrolyte leakage.

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