Eugene A. Talley

Chemical composition of potatoes. VII Relationship of the free amino acid concentrations to specific gravity and storage time

Prior to storage, Maine-grown Katahdin potatoes were sorted into five specific gravity classes. Samples of three classes (high, intermediate, and low) were stored in individual boxes at 38 F for eight months, 45 F for one month, and 50 F for one month. New York-grown Katahdins were sorted into specific gravity classes periodically after removal from storage. Both lots were analyzed periodically for free amino acids (including the amides). In general, an inverse relationship was found between total solids and free amino acids calculated on a dry weight basis in Maine-grown and New York-grown Katahdin potatoes. In most cases little difference was found on the fresh-weight basis. Changes in the amino acids during storage were quite random. The differences found in the amino acid values between samples due to sorting for specific gravity before and after placing in storage were minor.ResumenAntes del almacenaje, las papas Katahdin provenientes de Maine fueron clasificaadas en cinco clases de gravedad específica. Muestras de tres clases (alta, intermedia y baja) fueron guardadas en cajas individuales a 38 F por ocho meses, 45 F por un mes y 50 F per un mes. Las Katahdins provenientes de Nueva York fueron removidas periodicamente de su almacenaje para su clasificación en grupos de gravedad específice e inmediato análisis.Ambos lotes fueron analizados periódicamente para amino-ácidos libres (incluyendo las amidas). En general se encontró una estrecha relación inversa entre los sólidos totales y amino-ácidos libres, calculados sobre bases de peso seco en las papas de Maine y las de New York. En la mayoría de los casos se encontraron pequeñas diferencias sobre bases de peso fresco. Los cambios en los amino-ácidos durante el almacenaje se efectuaron al azar. Las diferencias encontradas en los valores de los amino-ácidos entre las muestras debidas a la clasificación para gravedad específica antes y después del almacenaje fueron menores.

Studies of the relationship of specific gravity to total solids of potatoes

SummarySpecific gravity and total solids data were studied statistically to test the absolute reliability of the relationship in American potatoes. On a limited number of samples it is strongly indicated that studies should be instituted in the United States to establish a regression curve especially suited to American varieties and growing conditions. The variation in the relationship, due to tissue air space and perhaps other causes, indicates doubt as to the absolute reliability of individual total solids values determined by means of specific gravity. This is amply demonstrated by the 95% confidence limit of ± 1.5% total solids.

Non-nitrogenous ninhydrin-positive compounds in ion-exchange chromatography identification of levulinic in hydrolyzed plant fractions☆

Abstract Ion-exchange chromatography of acid hydrolyzed kidney bean seed fractions revealed two major non-nitrogenous ninhydrin-positive peaks. The larger of the two was isolated and characterized as levulinic acid. Its sensitivity to the ninhydrin reagent at 570 mμ is approximately 1 100 that of leucine while its 570:440 mμ absorption ratio resembles that of some imino acids. Behavior on the ion-exchange column was noted for the isomeric angelicalactones, acetyllevulinic acid, levulinamide, γ-chlorovalerolactone, 2-ketogluconic acid, 5-ketogluconic acid and 2-ketoglutaric acid. Each gave a low order ninhydrin-positive reaction.

Chemical composition of potatoes. VIII. Effect of variety, location, and year of growth on the content of nitrogen compounds

Free amino acid content, total nitrogen, extractable nitrogen, ratio of extractable to total nitrogen, solids content, and specific gravity in Cobbler, Katahdin, Kennebec, Red Pontiac, and Russet Burbank potatoes was studied. Each variety was grown in six different locations (Idaho, Maine, Pennsylvania, Wisconsin, Long Island, and the Red River Valley) during the years 1961 through 1963. The mean values for each factor, with significant differences indicated, are listed along with the high and low range, the coefficient of variation and the overall mean. The percent of total variance contributed by each of the variables and their interactions also are listed. Long Island potatoes had the highest nitrogen and amino acid content. Varietal differences were less significant. Proline was the most variable of the constituents measured. Aspartic and glutamic acids had the highest variability with respect to years grown. The effect of each variable varies from one constituent to another.ResumenSe estudió el contenido libre de amino-ácidos, el nitrógeno total, nitrógeno extractable, proporción de nitrógeno extractable y total, contenido de sólidos y gravedad específica en las varledades de papa, Cobbler, Katahdin, Kennebec, Red Pontiac y Russet Burbank. Cada variedad fue cultivada en seis diferentes localidades (Idaho, Maine, Pennsylvania, Wisconsin, Long Island y en Red River Valley) durante los años de 1961 a 1963. Los promedios para—cada factor, con diferencias significativas, se especificaron de acuerdo con la variación alta y baja, coeficiente de variación y el promedio general. El porcentaje de variación total contribuido por cada una de las variables ysus interacciones también se especificaron. Las papas de Long Island tuvieron más alto contenido de nitrógeno y amino-ácidos. La diferencia varietal fue menos significante. La prolina fue el más variable de los elementos medidos. Los ácidos aspártico y glutámico tuvieron más alta variabilidad con respecto a los años en cultivo. El efecto de cada variable varió de un componente a otro.

Amino acid composition of freshly harvested and stored potatoes

Total amino acid contents of several important U.S. potato cultivars grown in Maine, Idaho and The Red River Valley are listed along with nitrogen content. Differences in amino acid content among cultivars were roughly proportional to differences in total nitrogen. The effect of storage on amino acids in two cultivars was minor. The limiting essential amino acids compared to egg were MET and the sulphur amino acids.ResumenSe presentan los contenidos de nitrógeno y del total de amino acidos de varios cultivares de papa importantes para los Estados Unidos, y cultivados en Maine, Idaho y el Red River Valley. Las diferencias en el contendio de amino acidos entre cultivares fue aproximadamente proporcional a las diferencias en el contenido de nitrógeno total. El efecto del almacenamiento sobre el contenido de amino acidos en dos cultivares fue pequeño. Los amino acidos esenciales más limitantes, comparados con los del huevo, fueron la mentionina y los otros aminos acidos asufrados.

Chemical composition of potatoes. III. Relationships between specific gravity and the nitrogenous constituents

SummaryKatahdin potatoes from Maine (1960 crop) were separated into high, intermediate, and low specific gravity levels immediately after harvest, then stored in the cold. Samples were withdrawn periodically for analysis. Concurrently, New York grown Katahdms were placed in cold storage and samples, when withdrawn for analysis, were separated into three specific gravity levels. The pre-separated Maine potatoes permitted more refined analytical data to be compiled. There was a progressive loss of weight during storage which was greatest in potatoes with the lowest solids content. Specific gravity changed very little during storage. The shrinkage therefore is due to a loss of solids and moisture in the ratio of the original composition. With only minor differences in the 1959 and 1960 growing seasons in Maine, there were marked differences in the composition of potatoes grown during these two seasons.

A preparative column for the ion exchange isolation of amino compounds

Abstract A preparative column is described, which gave a resolution equal to that of an analytical column run under the same conditions.

Protein nutritive value of potatoes is improved by fertilization with nitrogen

Dry matter yields and total-N percentages of potato tubers have been reported to increase with increasing application of fertilizers to potato plants. The concentrations of most of the amino acids found, have been reported to decrease, when calculated on the basis of grams of amino acid per 16 g total-N, which assumes that protein and amino acid contents are proportional to nitrogen content. Recalculation on a dry matter or absolute basis, however, shows increases of amino acid content with increasing nitrogen content of the sample. Similar effects are shown for EAAI, chemical scores, and feeding experiments.ResumenLos rendimientos de materia seca y el porcentaje de N-total en los tubérculos de papa, se incrementan aumentado la aplicación de fertilizantes a las plantas de papa. La concentración de la mayoría de los aminoácidos hallados tiende a decrecer cuando se calcula como gramos (g) de aminoácido por 16 g del N-total, procedimiento en el que se asume que los contenidos de proteína y aminoácido son proporcionables al contenido de nitrógeno. Sin embargo, al recalcular sobre materia seca o base absoluta, se observa un incremento en el contenido de aminoácido cuando se aumenta el contenido denitrógeno en la muestra. Se presentan afectos similares para EAAI, análisis químicos, y experimentos alimentarios.

Extraction of free amino acids

A solvent is percolated through the sample of freeze-dried potatoes in a column until no more free amino acids are extracted. The simple method can operate unattended and with other materials. NH3 and ARG are the last to be removed. Maillard intermediates survive.CompendioUn solvente es filtrado a través de una muestra de papas deshidratadas congeladas en columna hasta que no se extraigan más amino ácidos libres. Este método sencillo puede operar sin mayor atención así como tembién con otras materiales. NH3 y ARG son los últimos en ser extraídos. Los intermedios de Maillard sobreviven.