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

Summary

Thresholds 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.

Resumen

El 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.