THE MACADAMLA NUT IX HAWAII 
9 
RELA I ION OF SPECIFIC GB Wi I V TO TOTAL SUGARS 
Figure 3 shows the relationship of specific gravity to total sugars 
iu a series of smooth-shell kernels. There appears to be a definite 
positive correlation of the two where the percentages of sugar are 
high and the kernels are obviously immature. 4 The percentage of 
total sugars in normal, mature kernels varies from about 3 to 5 percent. 
Within this range there is little correlation. 
RELATION OF SPECIFIC GRAVITY TO ROASTING QUALITIES 
If kernels of varying specific gravities are rousted 1 there will be 
noted a marked relationship bet ween specific gravity and the character 
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4 6 8 10 12 \* 
TOTAL SUGARS IN KERNEL (PERCENT) 
Relation of total sugars in inarailanna kernels to specific gravity 
IG 
of the roasted product. Kernels of high specific gravity acquire a 
dark-brov n color, a strong scorched taste, and a, hard or tough con- 
sistency. At. the other extreme, the low specific-gravity kernels 
develop a lighl golden color, a, mild nutty flavor, and a crisp texture. 
Specific gravity may thus be used as a basis for grouping of macadamia 
nuts according to their adaptability t<> a commercial rousted product. 
A study whs conducted to determine the relation of various specific- 
gravity groups of kernels to roasting qualities. Six water solutions 
were made up of the following specific gravities: 1.100, 1.050, 1.025, 
1.000, 0.985, and 0.D70. Sodium chloride was used to make the solu- 
tions of specific gravity greater than unity while ethyl alcohol was 
used for the solutions of less than unity. The increments in specific 
* The terra "mature" is used in this bulletin to mean kernels which are plump in appearance and show- 
little shrinkage during curing. "Immature" kernels are defined as those which are shriveled and show 
considerable shrinkage during curing. 
5 The term "roasted" is used throughout this bulletin to indicate either oven roasting or oil cooking. 
Both methods were used. From the standpoint of evaluating kernel quality, the two arc interchangeable. 
20846°— 38 2 
