Ora Smith

Potato quality. I. Relation of fertilizers and rotation systems to specific gravity and cooking quality.

P U B L I S H E D B Y THE POTATO ASSOCIATION OF AMERICA S O M E R V I I ~ E , N . J . N E W B R U N S W I C K , N. J. OFFIC]~Bt8 A N D E X E C U T I V E COMMITq[q[gl9 C. H. M]~zGNIr _l~estdent . . . . . . . . . C o l o r a d o S t a t e C o l l e g e , F o r t C o l l i n s , C o l o r a d o l~. M. BLoI~l=rT, V~ee-Prea~lent . . . . . . . . . . . . C o r n e l l U n i v e r s i t y , I t h a c a , N e w Y o r k WM. H. M.~TIN, Bec. .Tre~. , Ba*tor . .Agr . E x p . Sta . , N e w B r u n s w i c k , N e w J e r s e y 0 t ~ SMITH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C o r n e l l U n i v e r s i t y , I t h a c a , N e w Y o r k h. M. W J m l . . . . . . . . . . . . . . . . . . . . . . & l a b a m a A g r . E x p . S t a t i o n , A u b u r n , A l a b a m a R. A. J~HLm . . . . . . . . . . . . . . . . . . U n i v e r s i t y o f M a r y l a n d , C o l l e g e P a r k , M a r y l a n d A. H. ]~-~DINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A g r . E x p . Sta . , G a i n e s v i l l e , F l o r i d a

Potato quality viii. effect of foliar applications of sequestering and chelating agents on after-cooking darkening.

SummarySeveral sequestering and chelating agents were sprayed on potato plants in the field. Observations and Hunter Color Difference Meter readings of boiled potatoes from these treatments indicate that several of these agents prevent or reduce after-cooking darkening. This probably results from the iron in the tubers being sequestered or chelated so that it is held in a non-ionizable form and cannot take part in a reaction with o-diphenols and therefore, prevents the normal formation of the dark colored pigment, a ferric-o-diphenol compound.

Maleic Hydrazide as a Sprout Inhibitor for Potatoes

treated individual seldom turns out to be completely tetraploid. Only some panicles and sometimes only a few grains in each panicle of each individual prove to be truly affected. Panicles with 4x tissues often fail to emerge completely from the sheaths. Besides this striking character, the size and shape of ripe spikelets from 4x tissues are very helpful in distinguishing them from the diploid. Not only are they larger, with coarser hairs, but their awns as a rule, are much longer than those of the original diploid (fig. 3).

Potato quality X. Post harvest treatment to prevent after cooking darkening

SummaryResults of these preliminary experiments indicate that after cooking darkening can be reduced or prevented by treating whole unpeeled potatoes with several chemicals after harvest. Concentrations, length of treatment and temperature during treatment need to be worked out more completely.

Potato quality XIII. Preventing after-cooking discoloration in oil blanched French fries

SummaryTreatment of slices with a 2% solution of Na2H2P2O7 in the blancher will prevent after-cooking darkening in par-fried French-fries. The Na2H2P2O7 seems to act as a sequestering agent in complexing the ferrous iron in a colorless form. The texture of the finished product is improved and uniform quality control of color is made possible. Sodium acid pyrophosphate does not increase the free fatty acids of the frying media and the increase in the per cent of P2O5 in the treated product is negligible. Frozen French-fries held at O F. that are discolored can be transformed into a creamy white product by dipping them for two minutes in a 2% solution of Na2H2P2O7 at 40 F. The pyrophosphate does not cause the detrimental effects on texture that some acids, sequestering, and chelating agents cause in the finished product.Several scvreen sizes of Na2H2P2O7 are manufactured. A fast reacting, fine particle size product is necessary for optimum results.

Potato quality IX. Use of sequestering agents in preventing after-cooking darkening in pre-peeled potatoes

SummaryA 60 second dip in a mixture of 1 per cent sodium bisulfite and 1 per cent sequestering agent (the di sodium or tetra sodium salt of ethylenediamine tetraacetic acid) effectively prevented after-cooking darkening of pre-peeled potatoes when there was a time lag of 24 hours or more between time of treatment and time of cooking.The prevention of after-cooking darkening by the use of sequestering agents is compatible with most recent theories as to the cause of darkening. Evidently the effectiveness of the sequestering agents is in the inactivation of the iron or iron and other metallic ions by forming a water soluable complex in which the metal or metals are held in a non-ionizable form which therefore prevents their oxidation after cooking and the resulting discoloration.

Varietal susceptibility of potatoes to internal black spot

Summary1Experiments were conducted to further test the correlation between black spot index and specific gravity, and to show the effect of field location on the relative response of various varieties to black spot and specific gravity.2A highly significant positive corelation of 933 was found between black spot index and specific gravity in 1949, using Long Island-grown Katahdin potatoes. We must conclude that there are other factors influencing blackening, but that there is an association between the specific gravity of the tuber and the black spot index.3The variety trials in 1949-1950 indicate that internal black spot is no longer just a Long Island problem, but is becoming increasingly prevalent throughout New York State.4The fact that location has an important effect on the incidence of black spot was demonstrated in the 1950–1951 trials. Several of the tested varieties reacted differently in blackening susceptibility when grown in certain counties. However, Ontario consistently blackened more than the other varieties in practically every location, whereas Ashworth, Pontiac and Kennebec showed the least susceptibility to discoloration of any of the varieties tested.5The most practical recommendations for the control of internal black spot are: (1) careful handling to avoid bruising, especially after very long storage and (2) the use of less susceptible potato varieties.

Potato research at Cornell University

PUBLISHED BY THE POTATO ASSOCIATION OF AMERICA SOMERVILLE, N . J . N E W BRUNSWICK, N. J. O F F I C E R S A N D E X E C U T I V E C O M M I T T E E C. H. M~rZGER, P r e s ~ d e n

Potato quality XV. Improving texture and measuring textural changes in potato flakes

. . . . . . . . . C o l o r a d o S t a t e Col lege , F o r t Col l ins , C o l o r a d o F. M. BLODGET% V ~ c e P r e s i d s n t . . . . . . . . . . . . Corne] l U n i v e r s i t y , I t h a c a , New Y o r k W•. H. IVIARTTN, 8 e e . T r e a ~ . , E d i t o r . . A g r . Exp. Sta., New B r u n s w i c k , New J e r s e y 0RA S~ITH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corne l l U n i v e r s i t y , I t h a c a , New Y o r k L. M. W ~ E . . . . . . . . . . . . . . . . . . . . . . A l a b a m a Agr . Exp . S ta t ion , Auburn , A l a b a m a R. A. JEHLE . . . . . . . . . . . . . . . . . . U n i v e r s i t y o f M a r y l a n d , Col lege P a r k , M a r y l a n d A. H. EDDINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Agr . Exp. Sta., Ga inesv i l l e , F l o r i d a

Functions of the protein and other nitrogenous fractions of potatoes in chip color development

SummaryMealiness or consistency is the most important textural factor in certain forms of processed potatoes. An objective method of measuring this has been shown using a modified L.E.E.-Kramer shear press. Addition of sodium acid pyrophosphate at various locations in the processing line will increase mealiness and prevent discoloration from after-cooking darkening.To substantiate textural changes, objective methods were used and the influence of moisture and flake ratio in the reconstituted products was shown. Microscopic examinations showed that SAPP-treated cells when ruptured did not lose their contents. As the ratio of water to flakes is increased the shear force is decreased. The temperature of the water also creates shear force differences, although the general slope of the curves are similar.Phosphorus concentrations in potato flakes are shown for various treatments with and without SAPP. Both ortho and pyro forms were analyzed and all treatments showed increased phosphorus concentrations. Total iron content was similar in all treatments but color scores were higher in the SAPP-treated samples.