Average composition of honeys by Lehman and Stadlinger (17 samples). a

DISCUSSION OF RESULTS.

PHYSICAL CHARACTERISTICS OF HONEYS.

The physical properties of the different honeys, color, granulation, aroma, flavor, etc., are indicated in the table only in a very general way. In color the honeys ranged from the pure white of the alfalfa, clovers, and other Leguminosa to the very dark color of the buckwheat. As regards granulation, 80 of the 100 honeys examined were more or less crystalline; the granulation in the honeys of high purity, such as the alfalfa, was sufficient to cause solidification. In fact, this solidifying property of alfalfa and other easily granulating honeys is now utilized by packers, who supply them in the form of briquettes wrapped up in paper packages. The popular preference for a liquid honey, on the ground that it is an indication of purity, is founded upon an entirely false opinion. In many cases the granulation caused only a partial solidification of the honey, with the formation of either a thin crystalline magma or of a compact deposit of dextrose crystals, the latter frequently of some size. The granulation of honey is largely influenced by temperature, being much more pronounced in winter than in summer.

Twenty of the honeys were entirely liquid and showed no indications of granulation. This condition was especially marked in the low-purity honeys, such as those largely derived from honeydew, and in honeys of high levulose content, such as the sage and tupelo. The non-granulating property of the sage is, in fact, utilized by packers for blending in order to prepare honeys which will remain liquid.

In two cases, honeys Nos. 40 and 89, the very fluid condition of the honey was due solely to an excess of water, these honeys containing from 8 to 9 per cent more water than the general average. This large amount of water was probably due to an unripe condition of the honey as a result of insufficient evaporation or reduction of the nectar by the bees. Honeys of high water content are apt to undergo fermentation changes, and the sour taste of sample No. 40 may be ascribed to this cause.

The aroma and flavor of the different honeys were usually typical and well marked for each special class, but these could be indicated only very imperfectly in the table, owing to the difficulty of describing sense perceptions of this character. In many cases the odor of the flower from which the nectar was derived was especially pronounced, as in the pennyroyal and orange. The alfalfa, basswood, buckwheat, cotton, and several other classes of honey had also each a characteristic odor and flavor. The presence of much honeydew in a sample could usually be detected by the very marked molasseslike odor and flavor, as in honeys Nos. 72, 85, 86, 96, 97, and 98.

POLARIZATION DATA.

MULTIROTATION.

In the polarization of the various honeys listed in the table it will be noted first of all that there is a decided difference in every case between the direct polarization made immediately and that made after standing overnight. This is due to the phenomenon of multirotation or birotation, a characteristic very commonly noted in the polarization of all reducing sugars. The individual figures for birotation as given in the table represent the value determined upon the liquefied honey, the average for all the honeys listed being about 3.6. If a heavily granulated honey be dissolved without previous liquefaction, the birotation is much more pronounced. The algarroba honey, No. 35, for example, when liquefied, had a multirotation of 4.2. A sample of this same honey unliquefied gave an immediate polarization of 5.6° V. and a constant of 21.7° V. The multirotation in this case is 16.1, nearly four times that observed in the liquefied honey.

The generally accepted explanation of the phenomenon of multirotation is the formation during solution of molecular aggregates of high specific rotation which gradually break down into simple molecules of lower polarizing power. In a honey which has been liquefied by warming until all crystals of dextrose are dissolved, these molecular aggregates would seem to be largely, though not entirely, broken down. The statement so frequently made that a solution of a sugar on standing will soon attain its normal constant rotation requires, therefore, some modification. No work seems to have been done upon the point of concentration at which sugar solutions begin to show multirotation, but the phenomenon probably obtains for all conditions of supersaturation. Any liquid honey which displays multirotation would probably granulate to a greater or less degree under favorable conditions. The reason that concentrated molasses, sirups, and glucoses do not exhibit multirotation would, therefore, be that the reducing sugars in these products do not. exist in a condition of supersaturation.

b

Frühling in a report upon the birotation of several honeys which he examined states that the change in rotation was the strongest in honeys which contained the largest amount of crystallized dextrose. In such granulated honeys the levorotation increases after solution in consequence of the decrease in the positive rotation of the dextrose. With honeys, on the other hand, which contain no crystals of dextrose the author above cited states that the levorotation decreases a Landolt, Das optische Drehungsvermögen, 2d ed., p. 243. Zts. öffentl. Chem., 1898, 4: 410-412.