Alasclear: A high quality scab resistant potato

Alasclear was released from the breeding program at Palmer to provide Alaskan potato growers with a variety as resistant to potato scab as Ontario and of much better quality than that variety. Alasclear has a clear skin and is very acceptable at harvest for chip manufacture. Ninety days from planting it accumulated high dry matter as indicated by 1.089 specific gravity. It continues to increase to 1.102 specific gravity over a period of 120 days.     

A non-destructive method for rapid evaluation of boiling quality of potato tubers

A non-destructive method for rapid evaluation of boiling quality of potatoes has been developed. The method is based on the degree of sloughing, after-cooking darkening and colour of tuber fractions (cores of 1.3 cm in diameter) cooked in test tubes at 118°C for 25 min. Using sixteen potato cultivars, with 20–30% dry matter content, boiling quality results obtained by the new method were compared to sloughing and after-cooking darkening values obtained by boiling quartered tubers in aluminum sauce pans on a standard electric stove. The correlation coefficient between sloughing data obtained by the two methods was 0.912 (P< -0.001). The new method has proven to be simple, reproducible and highly suitable for evaluating a large number of potato samples. This should make it attractive for routine use by potato breeders.     

Goldrush: A new high quality russet-skinned potato cultivar

On March 1, 1992, the North Dakota Agricultural Experiment Station announced the release of a new russet potato cultivar named Goldrush. Goldrush is an oblong, smooth, russet-skinned potato cultivar that has very white flesh, good culinary quality, resistance to hollow heart and is adapted for both the fresh and processing market.     

Effect of Triticum monococcum glutenin loci on cookie making quality and on predictive tests for bread making quality

The effects of Triticum monococcum glutenin loci on cookie making quality and predictive tests for bread making quality were evaluated in recombinant substitution lines (RSLs) between chromosome 1A^m from T. monococcum and chromosome 1A from Chinese Spring. All four combinations of high molecular weight (H M_r-GS) and low molecular weight glutenin alleles (L M_r-GS) were studied in a factorial design to evaluate their interactions. Grain protein content was used as a covariable to evaluate the effect of these loci independently of the variation in protein content among lines. No significant interactions were detected indicating an additive effect. RSLs carrying the HM_r -GS from T. monococcum showed a 13·6% increase in SDS sedimentation volume (p=0·004) and a significant reduction in cookie diameter (−5·2%,p =0·02), and cookie quality (−6·8%, p=0·02). RSLs carrying the LM_r -GS from T. monococcum showed a significant decrease in the proportion of polymeric protein (−2·8%, p<0·0001), SDS sedimentation volume (−8·1%,p =0·03) and gluten strength (−16·5%, p=0·01), and a significant increase in cookie quality (5·9%, p=0·05). The T. monococcum LM_r. -GS allele has potential value to be used in soft wheat breeding programs. These results suggest that diploid T. monococcum could be a valuable source for new allelic variation for storage proteins loci and new quality characteristics.     

Analytical methods for quality control of dried potato flakes

A set of analytical methods was used for the characterization of the oxidative degradation of dehydrated potato flakes. Headspace gas analysis for straight chain hydrocarbon (Ethane-hexane) and for oxygen was used to directly follow the oxidation. Bleaching was followed by quantitatively determining the carotenoid concentration. Analytical results obtained showed a strong association with taste testing results. The data reported show the effectiveness of natural and synthetic antioxidants for the stabilization of dried potato flakes.     

A portable monitor for the rapid assessment of processing quality of stored potato tubers

The present study assessed a commercially available, enzymatically based blood glucose monitor for the rapid determination of processing quality of tuber samples taken directly from storage. This monitor is based on reflectance photometry of a disposable test strip for a chromogen produced during the oxidation of glucose. The influence of storage conditions, harvest location, cultivar, reconditioning effects and the monitoring environment were examined for their effects on glucose levels and chip color. Glucose concentrations were determined by blood glucose monitor, high performance liquid chromatography (HPLC) or YSI biochemical analyzer. Crude tuber extracts did not adversely affect the determination of glucose by the blood glucose monitor and there was no evidence of any interaction between glucose concentration and extract in terms of test strip color development. The test strips demonstrated stable color retention for over an hour although values remained slightly higher after the initial potato extract test. Reaction of test strips to glucose was sensitive to initial temperature of the tuber extract with greatest accuracy exhibited in the 15–22 C range. Chip color was inversely correlated with tuber glucose content regardless of detection method, cultivar, growing site or storage temperature. The highly portable glucose monitor provided a rapid, accurate and quantitative profile of chip processing quality.     

Breeding progress for potato chip quality in North American cultivars

Forty-four potato cultivars, released in the period between 1876 and the present were grown concurrently in field trials, stored simultaneously in three different environments, then evaluated for chip quality. They represented cultivars historically used and/or bred for potato chip production. Quality factors measured were tuber solids, chip color, reducing sugar levels, sucrose levels, and percent of defect-free chips. Tuber solids tended to increase in the late period cultivars, but trends were erratic. The release of Lenape marked the beginning of an increase in tuber solids that has continued to the present. There was a significant trend for lower reducing sugars and better chip color that corresponded to increasingly later cultivar release dates. Since about 1960, progress toward lower reducing sugars and better chip color has been constant, regardless of whether tubers were stored at 4.4 C, stored at 4.4 C and reconditioned, or stored at 10 C. Late period cultivars tended to have a greater percentage of defect-free chips in comparison to those released earlier, with most of the improvement coming during the last few years. This study provided evidence that potato breeders have made significant progress in developing cultivars with good chip quality. Evidence was also found that Lenape was a landmark cultivar and has been an important contributor to the observed breeding progress     

Butte: A long Russet potato variety with excellent dehydrating quality

‘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.     

Evaluation of potato cooking quality in Argentina

Cooking quality of mature tubers was assessed for ten Argentine potato cultivars, two cultivars of foreign origin and three advanced clones. Specific gravity, dry matter and starch content, as well as quality of boiled potatoes and chips were determined Pampeana INTA had the highest dry matter content with 21.8 percent and would appear to be a very good cultivar for dehydrated products. The lowest dry matter values were obtained for three of the four most widely planted cultivars: Spunta, Bonaerense La Ballenera and Kennebec Kennebec demonstrated its good quality for chipping with a score of 6.9 points. Primicia INTA and Sureña INTA with high dry matter content and good features for chipping can also be used to produce chips Breeding under high temperatures during tuberization has proven to be a successful strategy in developing cultivars that are superior in dry matter contents to the cultivars currently imported from the northern hemisphere     

Cooking quality of some Dutch potato varieties

Summary The relationships among three methods for evaluating texture (sloughing during cooking, hardness of cooked potato dice and shear press value of French fries) and some chemical constituents (Ca, Mg, K, free pectin, phytin and citrate) were investigated, using the main specific gravity classes of seven Dutch potato varieties. The interplay of these constitutents (except K) in the softening of the texture during cooking was expressed as follows: Only the shear press value showed a relationship with the specific gravity. None of the textural-properties was geverned by the PC PMC number or by water uptake of raw slices. The same properties were determined after 50 and 100 days storage at 10 and 4 C. A decrease in sloughing and hardness, but an increase in shear press value occurred. PCMPC number also increased, but remained quite low, explaining its lack of influence on texture.     

Changes in potato starch quality during growth

Summary Potato starch quality parameters (amylose concentration, glucose-6-phosphate content and granule size) were analyzed in relation to the harvesting date and tuber size of four cultivars. A significant increase in the glucose-6-phosphate content and granule size of starch was observed during tuber growth, whereas the amylose concentration was constant. Granule size increased markedly, whereas glucose-6-phosphate content showed slightly increasing values with increasing tuber size. Amylose concentration showed no correlation with tuber size. We conclude that the changes in the granule size, glucose-6-phosphate and amylose content of potato starch during growth are independent of each other.     

Some effects of plant spacing on potato quality

Summary As plant population was increased so the dry matter content of the tubers increased, but delaying harvest had little such effect. Tubers of 2–3 cm (or 2.5–3.0 cm) had a lower dry matter content than tubers of 4.5–5.5 cm size at any one harvest. Increases in dry matter content were associated with increases in the disintegration of the tubers when cooked. The N content of the tubers was influenced by population, and although N content decreased and after-cooking blackening decreased with increasing plant population, after-cooking blackening was better related (inversely) to the K/N ratio of the tubers than to N content. Tubers from the later harvests had higher N, lower K and lower K/N ratio than those of a similar size at the earlier harvests. Published effects of fertilizer application on quality are related to similar effects obtained by varying the plant population.     

Processing and quality evaluation of sweet potato chips

A study was conducted to develop a process for producing sweet potato chips. Sweet potato tubers sliced to 0.5 by 0.5 cm size were dehydrated at 70°C for various times (0, 90, 105, 120, 135, 150, 165 min). Determination of the moisture content of the dehydrated chips and sensory evaluation of the dehydrated and fried chips were carried out to establish optimum dehydration time and moisture which corresponded to optimum quality. Blanching the slices in water and 1% sodium metabisulfite solution respectively prior to the dehydration significantly (P>0.05) improved the color and general acceptability of the chips over those immersed in water. The process development resulted in about 26 to 76% decrease in the ascorbic acid content of the chips. Significant changes also occurred in the total and reducing sugars of the chip following partial dehydration.     

Influence of potato composition on chip color quality

Potato constituents were monitored to evaluate their contribution to potato chip color. Five chipping potato varieties: Snowden, AC Ptarmigan, FL 1625, FL 1815 and ND2471-8 were evaluated. Ascorbic acid, sugars, phenolic acids, and amino acids were determined and quantified by High Performance Liquid Chromatography (HPLC) and the color of potato chips was measured by both CIELab Hunter-ColorQuest and Agtron instruments. Composition and chip color varied among the different varieties. AC Ptarmigan and ND2471-8 produced the darkest chip color (on average L*= 49.0, chroma=19.5, and hue angle= 62.9) compared with FL 1815 (L*= 58.4, chroma= 28.3 and hue angle= 75.7). Reducing sugar concentration did not completely explain or predict color quality when it was present in low concentrations (ca. < 60 mg/100g). Other reactants present in the potato slices played an important role in the final color quality of potato chips. Multiple correlation analysis showed negative association of ascorbic acid (r= -0.7), fructose (r= -0.7), a chlorogenic acid isomer (r= -0.7), glucose (r= -0.7) and glutamine (r= -0.5) with potato chip color. Sucrose, chlorogenic acid and asparagine were poor estimators of chip color quality.