Jorg Augustin

Changes in the nutrient composition of potatoes during home preparation: III. Minerals

The retention of water-soluble vitamins by several potato varieties using various home preparation methods was investigated. Retention values in general exceeded the 85 percent level for thiamin, niacin and vitamin B6, and the 70 percent level for ascorbic acid, riboflavin and folic acid. Overall, with but a few exceptions, whole, unpeeled, boiled and microwave cooked potatoes exhibited the highest vitamin retention.ResumenSe investigó la conservacion de vitaminas hidrosolubles en distintas variedades de papas, empleando diferentes métodos de preparation casera. Por lo general, los valores de retención de las vitaminas excedieron el nivel de 85 por ciento para tiamina, niacina, y vitamina B6 y el 70 por ciento para ácido ascórbico, riboflavina y ácido fólico. Con algunas excepciones, las papas enteras con cáscaras y las cocidas por microondas mostraron una mayor retención de vitaminas.

Mineral composition of freshly harvested potatoes

Nine Irish potato varieties from five growing locations were assessed for mineral content to determine the contribution of the potato toward meeting the U.S. recommended daily allowances for man. With the exception of calcium, the potato is a significant source of minerals for which U.S. recommended daily allowances have been established (iron, copper, iodine, magnesium, phosphorus, and zinc).ResumenSe evaluaron nueve variedades de papa cosechadas en cinco localidades, respecto al contenido de minerales, con el fin de determinar la contribucion de la papa para llenar las dosis recomendadas al hombre en los Estados Unidos. Con excepcion del calcio, se encontró que la papa es una fuente significativa de minerales para las necesidades diarias, incluyendo hierro, cobre, iodo, magnesio, fósforo y zinc.

The effect of soil moisture and nitrogen on yield and quality of the Russet Burbank potato

A study was conducted to obtain more information on the effects of soil moisture and nitrogen on yield and quality of the Russet Burbank potato.Total yield of tubers increased with nitrogen rates as a result of more tubers per plant and larger tubers but the percent of malformed tubers also increased. Increased nitrogen rates decreased of dry matter of tubers and increased the total amino-nitrogen content of the tubers.Placing all of the nitrogen in bands on each side of the row produced more tubers having growth cracks, culls and reduced yield of No. 1’s when compared with broadcasting.Applying a moisture stress to potato plants during the early tuber set period increased the percentage of malformed tubers having pointed stem ends, bottlenecks and dumbbell shapes; although total yield and grade of tubers were not significantly affected. Irrigating when available soil moisture was 75 or 85 percent instead of 65 percent during the growing season did not affect total yield, grade or tuber quality at the five percent probability level.ResumenSe realizó un estudio para obtener mayor información sobre los efectos de la humedad el nitrógeno sobre rendimiento y calidad de la papa Russet Burbank.El rendimiento total de tubérculos incrementó las dosis de nitrógeno como resultado de un mayor número de tubéculos por planta y de su mayor tamaño; pero aumentó el porcentaje de tubérculos mal formados. Asimismo, el incremento de las dosis de nitrogeno decreció el porcentaje de materia seca e incrementó el contenido de nitrógeno total y amino de los tubérculos.Colocando todo el nitrógeno en bandas a cada lado de la hilera, se produjo mayor numero de tubérculos con rajaduras, tubérculos sin valor comercial y redujo el rendimiento de tubérculos No. 1 en comparación con la incorporatión del abono esparcido. Sometiendo las plantas de papa a un periodo de deficit hídrico durante el inicio de la tuberización, se incrementó el porcentaje de tubérculos malformados con la zona apical alargada, constricciones y otras deformaciones, aunque el rendimiento total y el grado de los tubérculos no fueron significativamente afectados. Aumentando de 65% a 85% la humedad disponible previa a cada irrigación durante la estación de crecimiento, no afectó el rendimiento total, el grado o calidad de los tubérculos a nivel de 5% de significación estadística.

Precolumn phenylisothiocyanate derivatization and liquid chromatography of free amino acids in biological samples

Abstract A method for the analysis of free amino acids using precolumn phenylisothiocyanate derivatization and liquid chromatography was tested on a range of sample matrices: bovine plasma, dry cat food, dry infant milk formula and potatoes. The chromatographic resolution of the phenylthiocarbamyl derivatives of free amino acids was satisfactory, with few unidentified compounds present. Standard deviations for triplicate analyses were generally less than 10% of their means. 5-Sulfosalicylic acid (SSA) and a small pore membrane ultrafilter were tested for the deproteinization of bovine plasma. Recoveries of standards were highest when 1% and 4% SSA were used for deproteinization (98% average recovery), and lower (91%) when the ultrafilter was used. The 4% SSA treatment gave higher average free amino acid contents and protein removal than the other deproteinization techniques. These higher values were not due to protein hydrolysis by SSA. Interaction of free amino acids with plasma protein remaining after deproteinization may account for the lower free amino acid contents measured after 1% SSA and ultrafilter treatment. Deproteinization of plasma with 4% (w/v) (final concentration after mixing with the sample) SSA is recommended.

Influence of fertilizer irrigation and storage treatments on nitrate-N content of potato tubers

A survey was undertaken to investigate the nitrate-nitrogen (NO3-N) content of potatoes grown on different soil types with different fertilizer and irrigation treatments. Tuber nitrate-N contents were determined immediately after harvest and after periods of storage of up to 210 days.Nitrate-N in tubers (dry weight basis) ranged from low values of 82 to 122 ppm for low nitrogen fertility levels to a maximum of 192 to 285 ppm at the highest nitrogen rates, where irrigation was applied at optimum levels. The average nitrate-N in tubers under such conditions was 150 to 160 ppm. Where irrigation management was less than optimum, the nitrate-N content of tubers increased, reaching an average maximum value of 786 ppm at the highest fertilizer rate. The study showed that the nitrate-N level in tubers increased with nitrogen fertilization rates, although there was not a linear relationship between N fertilizer rate and tuber nitrate-N. The highest nitrate-N levels obtained in the tubers under proper irrigation management, even with 800 lb N/A, did not exceed 300 ppm nitrate-N and were usually less than 200 ppm. Data collected from this study suggest that improper irrigation, especially with high nitrogen fertilizer rates, results in a dramatic increase in nitrate-N level in the tubers. Some individual tubers contained over 1200 ppm nitrate-N. There was an apparent slight increase in nitrate-N in the tubers with storage, although this increase was not consistent.ResumenSe realizó un estudio para investigar el contenido nitrógeno-nitrato (N-NO3) de papas desarrollados en diferentes tipos de suelos con diferentes tratamientos de fertilización e irrigación. El contenido de, N-nitrato fue determinado inmediatamente después de la cosecha y después de periodos de almacenaje de hasta 210 días.El N-nitrato en tubérculos (en base a peso seco) estuvo entre valores bajos como 82 a 122 ppm para bajos niveles de fertilidad y máximos de 192 a 285 ppm a los mas altos niveles de nitrógeno, cuando la irrigación fue aplicada a niveles optimos. El promedio de N-nitrato en tubérculos bajo tales condiciones fue de 150a 160 ppm. Cuando la irrigacíon fue menor que el Óptimo, el contenido de N-nitrato de los tubérculos incrementó, alcanzando un valor promedio máximo de 786 ppm al nivel de fertilizante mas elevado. El estudio mostró que el nivel de nitrógeno nitrato en tubérculos incrementó con los niveles de fertilización nitrogenada, si bien no hubo una relatión lineal entre las dosis de fertilización nitrogenado y el N-nitrato de los tubérculos. Los niveles mas altos de N-nitrato obtenidos en los tubérculos bajo apropiadas prácticas de irrigación, aun con 800 libras de nitrógeno por acre, no excedieron de 300 ppm de N-nitrato y fueron usualmente menores que 200 ppm. Datos obtenidos en este estudio sugieren que impropia irrigación, especialmente con altas dosis de ferilizante nitrogenado, resulta en un incremento dramático en el nivel de N-nitrato en los tubérculos. Algunos tubérculos individuales contenían sobre las 1200 ppm de N-nitrato en los tubérculos con el almacenaje, y si bien este incremento no fue consistente.

Butte: A long Russet potato variety with excellent dehydrating quality

Abstract‘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.ResumenEl Servicio de Investigación Agrícola del Departamento de Agricultura de los Estados Unidos y las Estaciones Experimentales Agrícola de Idaho, Oregón y Washington, lanzaron en Abril de 1977 una nueva variedad de papa alargada y casposa denominada BUTTE. Sus tubérculos son similares a aquellos de “Russet Burbank” aunque BUTTE ofrece varias ventajas para los agricultores y procesadores. BUTTE tuvo un 7% de mayor rendimiento y 25% más en el grado U.S. N° 1 que “Russet Burbank” en una combinación de pruebas conducidas en 51 localidades/año en el sur de Idaho, al este de Oregón y en la hoya del rió Columbia. En estos experimentes su gravedad especffica promedio fué de .004 más alta que la de “Russet Burbank”. Su calidad para el deshidratado es también superior y el producto tiene una vida más larga. La calidad de BUTTE para papas fritas es buena a pesar de que acumula, en almacenamiento, ligeramente más azúcar que la “Russet Burbank”. Su contenido de vitamina C y proteinas en promedio ha sido 58% y 20% respectivamente, mayor que aquellos de “Russet Burbank”. BUTTE es hipersensible al virus X y resistente a la necrosis en red. Su reacción a otras enfermedades es similar a aquella de “Russet Burbank”.

Stability and utilization of picloram, vitamins, and sucrose in a tissue culture medium

Nicotinic acid, pyridoxine, and picloram were stable in a liquid MS culture medium (pH 5.5–5.6) during autoclaving and during cell-free incubation in the dark at 5°C or 25°C for up to 6 weeks. Thiamine loss under the same conditions was 16% at 5°C and 18% at 25°C. Five percent of the sucrose in the liquid medium was hydrolyzed during autoclaving. During cell-free incubation in the light (100 μE m−2 s−1) at 25°C, pyridoxine was not detected after 6 days, while 78% of the picloram and 56% of the thiamine were degraded after 6 weeks. All of the niacin and pyridoxine, 13% of the picloram and 42% of the thiamine in a liquid MS culture medium were utilized in 4 days by potato (cv. Lemhi Russet) tuber suspension cultures growing in the dark at 25°C.

CHANGES IN THE NUTRIENT COMPOSITION OF POTATOES DURING HOME PREPARATION: I. PROXIMATE COMPOSITION

The effects of various home cooking methods on the proximate composition of four potato varieties were investigated. The results revealed significant increases in the dry matter content of tubers during oven-baking and microwave cooking. With one exception, cooking unpeeled tubers in boiling water did not significantly alter their proximate composition. Boiling peeled tubers resulted in a significant decrease in the total ash content. Except for one variety, there was a significant decrease in crude fiber in boiled peeled and oven-baked potatoes. Changes in protein values were erratic.ResumenSe investigó el efecto de varios métodos caseros de cocción, en la composición proximal de cuatro variedades de papa. Los resultados demostraron un incremento significativo en el contenido de materia seca durante el horneado y la cocción por microondas. Con solo una exception, los tubérculos sancochados con cáscara no alteraron significativamente su composición proximal. Los tubérculos sancochados sin cáscara, si disminuyeron significativamente su contenido de cenizas totales. Excepto una variedad, hubo una disminución signififcativa de fibra cruda en papas sancochadas y en papas horneadas. Las variaciones en el contenido de proteina no fueron consistentes.

Yields and nutrient composition of the solid and liquid portions of selected canned fruits

Abstract Yields, proximate, vitamin, mineral, and trace mineral composition as well as sugar profiles were determined for the liquid and solid portions of canned peaches, pears, and pineapples which were procured from various commercial processing operations in the United States. In general water-soluble compounds were evenly distributed between the solid and liquid portions. Protein, fat, fiber, folic acid, and carotene were more concentrated in the fruit than in the liquid. Storage resulted in a decrease of folic acid values only. For some unexplainable reason there was an increase of vitamin B6 and carotene during storage. Storage also reduced the sucrose concentrations in all pineapple samples, but increased fructose and glucose only in pineapple chunks and not in sliced pineapples. The use of light syrup or juice reduced the caloric content of a product considerably compared to the heavy syrup counterpart. From a nutritional standpoint, except for sugar contents, little difference exists between the heavy and light syrup packs, nor was there a difference between the different cuts of the fruits.