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Russet Burbank potatoes were chilled at 25 F (−3.8 C), 27.5 F (−2.5 C), or 30 F (−1.1 C) for various periods of time and were then held at 45 F (7.2 C) for one or four weeks before testing. Susceptibility to injury was quite variable between the two crops and among tubers of the same lot exposed to the same treatment. The greatest amount of low temperature breakdown occurred in tubers chilled at 27.5 F (−2.5 C) for 10 hours. Flesh color, reducing sugar content, mealiness, and amount of sloughing in tubers that survived chilling were not markedly different from those in control samples although certain trends were observed indicating that the quality of chilled tubers was beginning to deteriorate. Chilling increased yellowness of flesh color in most treatments and darkness in several. Chilled tubers had a reducing sugar content slightly to moderately higher than the controls. They sloughed less than the controls and tended to be less mealy

‘BUTTE’, a new long russet potato variety, was released by the Agricultural Research Service, U. S. Department of Agriculture and the Idaho, Oregon, and Washington Agricultural Experiment Stations in April, 1977. Its tubers are similar to those of ‘Russet Burbank’ but BUTTE offers several advantages to growers and processors. BUTTE has averaged 7% more total yield and 25% more U.S. No. 1’s than Russet Burbank over 51 location-years of testing across southern Idaho, eastern Oregon, and in the Columbia Basin. Its specific gravity in these trials averaged .004 higher than that of Russet Burbank. Dehydrating quality of BUTTE is superior to that of Russet Burbank and the product has longer shelf life. BUTTE french fries well although it accumulates slightly more sugars in storage than does Russet Burbank. Its vitamin C content has averaged 58% higher and protein content 20% higher than that of Russet Burbank. BUTTE is hypersensitive to virus X and resistant to net necrosis. Other disease reactions are similar to those of Russet Burbank.

Chlorpropham (CIPC)3 concentrations were measured in peel samples of tubers taken from large commercial potato storages and from test bins after aerosol application. Tuber samples were taken at different levels within the pile and at numerous sites near the surface. The minimum concentration of CIPC in the peel layer for complete inhibition of sprouting was estimated to be 20 ppm. Immediately after commercial application of CIPC, 99% of the sample sites had concentrations high enough to completely inhibit sprouting, and residues in the peel were generally highest in samples obtained from the surface and from the bottom of the pile. CIPC concentrations decreased during the storage season in nearly all sites tested. Storages differed in the rate at which CIPC was lost. Mean peel residues fell below the level necessary for sprout inhibition in some storages but not in others. The rate of CIPC loss increased at the same time that air movement to maintain the desired temperature increased. With the 20 ppm threshold level as a guide, it is possible to monitor commercial storages for sprout-inhibition status. Retreatment before peel residues drop below 20 ppm can extend sprout inhibition in storage.

There has been a marked increase in the length of time potatoes are stored. The cost of storing potatoes for longer periods of time has been controversial because of the lack of acceptable figures relating to the various factors involved. This paper summarizes the costs involved due to various storage environments and various storage periods. In addition to representative investment and operational costs, the costs of weight losses, quality changes, and peel and trim losses are presented.

(1975). The Heat Balance in a Potato Pile. Acta Agriculturae Scandinavica: Vol. 25, No. 2, pp. 81-87.

A more precise method of expressing the ventilation rate of potato piles of different heights is to express the air volume per bottom area or as air velocity instead of air volumer per unit of time per unit of mass or volume of potatoes.

Idaho-grown Russet Burbank potatoes were evaluated at monthly intervals during 12 months of storage to determine changes in mealiness, sloughing, and specific gravity. Storage treatments included untreated samples stored at 38 F, 45 F, and 52 F; two samples stored at 45 F, one of which had been treated with MH sprout inhibitor and the other with CIPC; and one untreated sample stored at 38 F and conditioned at room temperature one week before evaluation.

Reducing and total sugar assays and cooked flesh color measurements were made on Idaho-grown Russet Burbank potatoes at monthly intervals during 12 months of storage. The six storage treatments included untreated tubers stored at 38 F, 45 F, and 52 F; untreated tubers stored at 38 F followed by one week of conditioning at room temperature; tubers treated with MH-30 stored at 45 F; and tubers treated with CIPC stored at 45 F. The tubers stored at 45 F contained significantly less reducing and total sugars and were significantly lighter in color than those stored at 38 F. Tubers stored at 45 F were comparable to those stored at 52 F in sugar content and color and had a longer storage life. Treatment with MH-30 or CIPC had no effect on sugar accumulation and no important effect on color. Conditioning potatoes from storage at 38 F for one week at room temperature significantly decreased the contents of total and reducing sugars, although they remained significantly higher than those of tubers stored at 45 F. Conditioning did not reverse the yellow color which had developed during 38 F storage.

Field trials have shown that Shoshoni is adapted to southeastern Idaho; it has consistently produced high yields, with dehydrating quality comparable to that of Russet Burbank. Shoshoni is late-maturing and the tubers are round to oblong, slightly flattened, and moderately netted. Shoshoni possesses moderate resistance to common scab and Verticillium wilt.

Idaho-grown Russet Burbank potatoes treated with a sprout inhibitor were stored at 42 F, 45 F, and 48 F for 11 months. Monthly quality evaluations showed that tubers stored at 42 F were less mealy, contained more reducing sugars, and were yellower in color than those stored at 45 F or 48 F. The latter two treatments were not significantly different in mealiness and were generally similar in yellowness of color. Tubers stored at 48 F had less reducing sugars than those stored at 45 F. Although all treatments resulted in a gradual darkening of the potatoes during storage, differences in grayness among the three storage treatments were minor from a practical standpoint. It is suggested that a storage temperature no lower than 45 F be used to maintain the internal quality of Russet Burbank potatoes.

The data reported herein show that maintaining at least 95% relative humidity in the ventilating air caused significantly less weight loss than ventilating with air of 85% relative humidity. In addition, significantly less flattening, shrivelling, and sprouting were found in tubers ventilated with air of 95% relative humidity. There was no difference between the two air humidities in the amount of rot found. Intermittent ventilation allowed significantly less weight loss than continuous ventilation. Also, intermittent ventilation caused significantly less flattening, less shrivelling, and less sprouting than continuous ventilation. The processing data indicate that tubers ventilated with air of 95% or more relative humidity resulted in less peel loss, less trim loss, lower sugars content, and in general, produced higher-quality processed products than when the tubers had been ventilated with air of 85% relative humidity.

Three storage trials involving Idaho-grown Russet Burbank potatoes showed that storage at 45 F resulted in less weight loss than storage at 38 or 52 F. Unwashed potatoes stored at 45 F had less storage loss throughout a 345-day storage period than tubers from the same source stored at 38 or 52 F. Washed tubers destined for the fresh market and treated with various inhibitors in April had less loss after 90 days of storage at 45 F than at 38, 52, or 59 F, but after 130 days of storage, 38 F showed the least loss. Washed and unwashed potatoes stored at 45 F in CIPC treated bags for 92 days showed less loss than those stored at 38, 52, 59, or 68 F.

In Part 1 of a planned series of articles on preservation of foods of plant origin by gamma irradiation, the current state of research on the technological, nutritional, and biochemical aspects of sprout inhibition of potatoes and other tuber crops are reviewed. These include varietal responses, dose effects, time of irradiation, pre- and postirradiation storage, and handling requirements; postirradiation changes in carbohydrates, ascorbic acid, amino acids, and other nutrients; respiration; biochemical mechanisms involved in sprout inhibition; wound healing and microbial infection during storage; formation of wound and light-induced glycoalkaloids and identification of irradiated potatoes. The culinary and processing qualities with particular reference to darkening of boiled and processed potatoes are discussed. The prospects of irradiation on an industrial scale as an alternative to chemical sprout inhibitors or mechanical refrigeration are considered.