Elizabeth F. Murphy

Detection threshold of sensory panels for mealiiness of baked potatoes as related to specific gravity differences

SummaryThresholds of mealiness detection in baked potatoes were demonstrated in three series of tests each representing three specific gavity levels within a broad range of 1.096 to 1.056.Only one of 15 contrasts of 0.002 differences in specific gravity was detected significantly by 29-member panels in three 6-sample tests of stored Russet Burbank potatoes.With comparable potatoes differing by 0.004 (three samples each in three studies), perception by 23- to 28-member panels was significant in five of six contrasts in complete blocks with four tastings, and in all six contrasts by paired comparison presentation, eight tastings.When specific gravity differences were 0.006, four three-sample complete-block tests revealed significant discernment by 28 to 30 judges in all eight contrasts (two in Russet Burbanks and six in Kennebecs, all newly-harvested).Sensitivity of perception in the one Russet Burbank 0.006 test was significantly greater than in three Russet Burbank tests with samples differing by 0.004 and in two of three Kennebec tests differing by 0.006.Panel sensitivity was not related significantly nor consistently to the specific gravity levels tested.Coefficients of correlation, determination, and regression of the 0.002 series showed weak association (r2s of 0.36 to 0.51) between mealiness rankings and three combined physical measurements: specific gravity, total solids, and alcohol insoluble solids. With larger differences, the relationships of mealiness to the measured characteristics were strong and of practical as well as statistical significance. The r2s ranged from 0.76 to 0.88 for the 0.004 samples and 0.84 to 0.95 for those in the 0.006 series.The minimum detectable specific gravity difference of 0.004 was coincident with a mean total solids difference of 1.05 gm/100 gms and an alcohol insoluble solids difference of 1.13 gm/100 gms of cooked riced potato.ResumenEl punto mínimo de revelación de la harinosidad en papas asadas fue demostrado en tres series de experimentos, cado uno representando tres niveles diferentes de gravedad especifica, a saber, de 1.095 a 1.085; de 1.085 a 1.075; y de 1.075 a 1.065.Solamente uno de los 15 contrastes de 0.002 fue significativamente descubierto por un jurado de 29 miembros en tres experimentos de seis muestras cada uno con papas Russet Burbank almacenadas.En papas similares, con variantes de 0.004 (tres estudios con tres muestras cada uno), la percepción de un jurado compuesto de 23 a 28 miembros fue sifnificativa en cinco de los seis contrastes, con cuatro saboreos en bloques completos, y en todos los seis contrastes en una comparación presentada en pares, con ocho saboreos.Cuando las diferencias en gravedad especifica fueron de 0.006, cuatro experimentos de tres muestras en bloque completo, revelaron significativos discernimientos en los 28 a 30 jueces, en todos los ochos contrastes. (Dos en la variedad Russet Burbanks y seis en la Kennebec, todas recién cosechadas.)La sensibilidad de percepción en el experimento de 0.006 con la Russet Burbank fue significativamente mayor que en dos de los tres experimentos comparables con Kennebec, y que en los tres experimentos con la Russet Burbanks con muestras vardiando en los 0.004.La sensibilidad del jurado no pudo ser relacionada significativa ni consistentemente a los niveles de gravedad especifica experimentados.

Effect of pentachloronitrobenzene soil treatment on flavor of potatoes

Pentachloronitrobenzene (PCNB) was applied to the soil prior to planting at the following rates of active ingredient per acre: 50 pounds at Maine and at North Dakota in 1959, 12.5 and 25 pounds at North Dakota and 20 pounds at Maine in 1960, and 50 pounds at New Jersey in 1961. One or more panels evaluated the flavor of the potato samples.No off-flavors were reported when potatoes were grown in soil treated with 12.5 or 25 pounds of active PCNB per acre at the one location. Off-flavors were found with PCNB treatment with 20 pounds active ingredient at one location and with 50 pounds active ingredient per acre at three locations.

Potato flavor quality as affected by two fungicides

In 1964, eleven weekly foliar spray applications of one and two pounds of Difolatan and one and two pounds of Maneb had no significant effect on the flavor quality of the baked Katahdin tubers examined in the study.

The flavor of small immature tubers compared with mature Katahdin tubers

The flavor quality of seven immature potato samples (three varieties, four numbered selections) was found to be ‘equal to’ or ‘poorer than’ the flavor of mature Katahdin tubers stored for 10 months at 45 F (7.2 C). The samples were evaluated by a panel of 21 experienced judges.

The determination of a mid-scale reference standard for baked potato mealiness

Eleven sensory tests (six with Kennebecs and five with Russet Burbank) of five to seven baked potato samples varying in specific gravity by 0.004 were conducted to relate the mid-scale mealiness rating by sensory panels to a characteristic specific gravity (raw) and total solids (cooked).The means for specific gravity values associated with the midpoint mealiness rating as estimated from the regression analyses for each test were 1.077, (S.E. 0.0068) for Kennebecs and 1.080, (S.E. 0.0071) for Russet Burbanks, and the means for total solids were 20.8, (S.E. 0.94) and 21.9, (S.E. 1.91) gms/100 for the two varieties respectively.The differences between the varietal means of specific gravities and total solids associated with “0” mealiness ratings were not statistically significant.The means (both varieties) for specific gravity and total solids for all eleven tests (both varieties) associated with the mid-scale point were 1.078, (S.E. 0.004) and 21.32 gms/100, (S.E. 0.87).There was some indirect evidence that the 5-point scale and/or the descriptive terms were inadequate to classify the mealiness of the potatoes tested.ResumenEn una evaluación por paneles, once ensayos organolépticos (seis de la variedad de papa Kennebecs y cinco de Russet Burbank), de 5, 6 o 7 muestras de papas asadas, cuya gravedad específica variaba cada 0.004, fueron llevados a cabo con el fin de relacionar el punto medio de harinosidad de la escala con una característica de gravedad específica (no cocinado) y sólidos (cocinado); para usar como criterio de muestra control (marcada) de referencia.Análisis de regresión para cada test mostraron que:—La gravedad media específica asociada con el punto medio de harinosidad fue 1.077±0.0068 para Kennebecs y 1.080±0.0071 para Russet Burbank; y la media para sólidos totales fue 20.8±0.94 y 21.9 ±1.91 gms/100, para las dos variedades respectivamente.—Las diferencias varietales entre las medias de gravedad, específica y sólidos totales, asociadas con harinosidad 0, no fueron estadisticamente significativas.Las medias calculadas para gravedad específica y sólidos totales en los 11 engayos (ambas variedades) asociadas con el punto medio de la escala fueron: 1.078 (S.E. 0.004) y 21.32 gms/100 (S.E. 0.87).Se encontró una evidencia indirecta de que una escala de cinco puntos y/o los términos descriptivos son inadecuados para classificar la harinosidad de las papas probadas.