MAPLE SIRUP PRODUCERS MANUAL 



69 



to produce the unwanted flavor. The formation 

 of this buddy substance is accompanied by an 

 increase in the free amino acids in the sap. 

 Whether this parallel increase in free amino 

 acids is involved in the foi-mation of buddy 

 flavor remains to be determined. 



Often some trees in a sugar grove "bud" 

 earlier than the rest. These trees should be 

 identified and marked so that their sap will not 

 be collected late in the season. To combine the 

 sap from trees that have budded with that from 

 the other trees would spoil the entire lot of late- 

 season sap. 



The practice of treating the taphole with 

 germicidal wllets will cause the sap to flow late 

 in the season and when the tree is far enough 

 out of dormancy so that the sap is buddy. 

 Test for Buddy Fhivor 



It is essential that sap produced during or 

 following a warm spell or from trees whose 

 buds have swelled be tested for buddiness 



The best and simplest test is easily performed 

 by bringing V4 cup of the sap or sirup to be 

 tested to a boil and sniffing the steam. If the 

 buddy flavor substances are present, they can 

 be detected in the steam. The sap or sirup can 

 be heated with an electric immersion-type 

 heater used for making instant coffee. This test 

 is subjective, and the buddy odor may not be 

 strong enough to be easily recognized by some 

 people. 



Another test that is applicable to sirup and 

 not subjective has therefore been developed. 

 This test involves the chemical test for amino 

 acid groups whose presence in sap parallels 

 buddy flavor formation (115). 



To make the test the following equipment is 

 needed: 



A 1-ounce (30 ml.) screw-cap bottle to hold the 

 standard amino niti'ogen solution. 



A box of wooden toothpicks. 



Test papers — filter paper cut into ^/a- x 4- inch 

 strips. 



The following reagents should be used: 



Standard amino nitrogen solution. This is 

 made by dissolving .5 grams of leucine (an 

 amino acid) in 30 milliliters of water. 

 (Place 1 level teaspoon of leucine in the 1- 

 ounce bottle and fill it to the neck with 

 water.) 



Ninhydrin spray. This is commercially availa- 

 ble as an aerosol spray. 

 The test should be made as follows: 



(1) To a small volume of the sirup to be te.sted, 

 add an equal volume of water and mix thor- 

 oughly. 



(2) With a pencil make three dots 1 inch apart 

 down the center of the test strip, 1 inch from 

 either end. Label X, S, and W. 



(3) Holding a toothpick in a vertical position, 

 dip the broad end into the diluted sirup and 

 transfer a drop to the pencil dot at the top of 

 the paper labeled X. 



(4) Using fresh toothpicks, transfer a drop of 

 the standard amino nitrogen solution to the dot 

 at the center of the paper labeled S, and a drop 

 of water to the dot at the bottom labeled W. The 

 size of the wetted spots should be about the 

 same. 



(5) Lay the paper on a clean, diy surface 

 (piece of filter paper) and allow the spots to dry 

 at room temperature. 



(6) Spray the entire paper strip with the 

 ninhydrin reagent. Wet the paper thoroughly 

 but not enough to cause the reagent to run. 



(7) Dry the sprayed paper at room tempera- 

 ture. 



(8) Heat the paper at a temperatui-e of 175° to 

 195° F. for approximately 1 minute to hasten 

 development of the color. The lid of a boiling 

 kettle or other moderately hot surface will suf- 

 fice. (From 1 to 2 hours will be required for the 

 color to develop at room temperature.) 



(9) Development of a violet color constitutes a 

 positive test and indicates that the sap is 

 buddy. 



The standard amino nitrogen solution is used 

 to indicate that the ninhydi-in reagent is react- 

 ing properly to give violet color with amino 

 compounds. 



Ninhydrin reagent is a very sensitive stain. 

 Care must be taken to keep the paper test 

 strips clean. Handling the test strip with for- 

 ceps, especially after staining, will prevent fin- 

 gerprints which could produce false-colored 

 spots. The papers are best sprayed by hanging 

 them in an open cardboard box to prevent 

 discoloration of other objects by the ninhydrin 

 spray. The ninhydrin i-eagent is not stable and 

 should be replaced at least every 6 months. 



